Dissertations / Theses: 'Degeneration and regeneration'

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Wernicke, Catrin V. [Verfasser]. "Degeneration, Protektion und Regeneration dopaminerger Neurone / Catrin V. Wernicke." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2011. http://d-nb.info/1025239318/34.

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Charge, Sophie Barbara Pauline. "Skeletal muscle hypertrophy : its regulation and effect on muscle regeneration." Thesis, King's College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340500.

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Saini, Amarjit. "The molecular and cellular aspects of muscle degeneration and regeneration." Thesis, Manchester Metropolitan University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585529.

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The concept of skeletal muscle homeostasis - often viewed as the net balance between two separate processes, namely protein degradation and protein synthesis - are not occurring independently of each other, but are finely co-ordinated by a web of intricate signalling networks (Nader, 2005). Such signalling networks are in charge of executing environmental and cellular cues that ultimately determine whether muscle proteins are synthesised or degraded. Prolonged elevations of proinflammatory cytokines are closely associated with muscle wasting that occurs during the sarcopenia of ageing and in cachectic AIDS and cancer patients (Strle et a/. 2007). These clinical disorders occur along with a decline in IGF-I anabolic activity, which is consistent with in vitro findings in muscle progenitor cells (Strle et a/. 2007). Very low concentrations ofTNF-a (0.01-1 ng.ml") inhibit IGF-I-induced protein synthesis (Broussard et a/. 2003; Strle et al. 2004) and expression of the critical muscle differentiation factors, MyoD (Strle et a/., 2004) and myogenin (Broussard et al. 2003; Strle et a/. 2004). Potential treatments that might overcome TNF-a-induced hormone resistance in myoblasts are unknown. Increased activation of the IGF/insulin pathway is an attractive target for combating many of the cachectic conditions associated with muscle wasting. Using rodent skeletal muscle cell lines we have investigated TNF-a/IGF-I interactions, in an attempt to mimic and understand mechanisms underlying the wasting process. We hypothesised that treatment of mouse myoblasts with TNF-a at specific doses ranging from high (20 ng.ml') to low (1.25 ng.ml") would result in dose-dependent block of differentiation and induction of apoptosis and that subsequent IGF-I co-incubations would stimulate myoblast survival and myotube formation. Objectives were to ascertain signalling pathways underpinning these outcomes. In contrast to our hypothesis, a novel role of IGF-I has been identified whereby eo-incubation of skeletal muscle C2 cells with IGF-I (1.5 ng.ml') and a non- apoptotic dose of TNF-a (1.25 ng.ml"; sufficient to block differentiation) unexpectedly were shown to facilitate a significant four-fold increase in myoblast death (P < 0.05). Specificity of the apoptotic potential of this growth factor was confirmed when neither bFGF-2 nor PDGF-BB (10 or 30 ng.ml' and 1.25 or 5 ng.rnl", respectively) were able to reveal the apoptotic potential of low dose TNF-a. By contrast, but in line with our II hypothesis, dosing with 10 ng.ml" TNF-a resulted in a block of differentiation and initiation of apoptosis, which was rescued by IGF-1. Preliminary signalling studies suggest that MAPK activation rather than the caspases are involved in the induction of death associated with low dose TNF-a (1.25 ng.mrl)/IGF-I incubation and therefore blocking the caspases would be without effect in this circumstance. The PI(3)K pathway is involved in the survival effects of high TNF-a (10 ng.mrl)/IGF co-incubations. Importantly, the rescue of death (regardless of the means required) did not facilitate differentiation and did not rescue the block of expression of IGF-ll or IGFBP-5 (produced by skeletal myoblasts as early events in their terminal differentiation and associated with preventing cell death) in our models. Using array technology we further established potential insulin survival and apoptotic genes that were upregulated in the above conditions and confirmed their expression with qRT-PCR. Of these genes three were selected to conduct gene silencing experiments. The gene silencing studies were effective in reducing expression of Adrald, Birc2 and Sirtl. Our findings suggest that inhibition of Adrald leads to an increase in myoblast death in conditions that are associated with myoblast survival and include basal conditions. This novel finding indicates Adrald expression to be essential for the general maintenance of myoblasts. This may be due to the multiple signalling pathways which the al-ARs regulate which include the PI(3)K-Akt pathway that is associated with growth and anti-apoptosis. Birc2 expression, which is upregulated in our cell model under conditions of myotoxic stress showed no significant effect on myoblast survival when suppressed. Associated with inhibition of apoptosis, it was hypothesised that inhibition of Birc2 would result in an increase in myoblast death however levels of damage were comparable to control myoblasts. Recent articles have stated that Birc, only when overexpressed above physiological levels, is associated with anti-apoptosis and consequently have proposed an alternative nomenclature that names the family after its distinctive structural feature, the BIR, rather than by inhibitor of apoptosis proteins lAPs (Silke & Vaux, 200 l; for review Srinivasula & Ashwell, 2008). Finally Sirtl, similar to Birc2 was highly expressed in conditions that induced the greatest incidence of myoblast death. Subsequent inhibition resulted in further increase in death which was not observed under basal conditions where myoblasts received DM alone. Unlike Adrald, this implicates Sirtl expression as a III survival mechanism which is specific for conditions associated with myotoxic stress. The mammalian Sirtl deacetylase was originally shown to modulate life-span in various species. However, the molecular mechanisms by which Sirtl increases longevity and with regard to the present study, survival, are largely unknown. In mammalian cells, Sirtl appears to control the cellular response to stress by regulating the FOXO family of Forkhead transcription factors. The FOXO family members are negatively regulated by the PI(3)K-Akt signalling pathway. Mammalian FOXOs control various biological functions, including cell cycle arrest, differentiation, repair of damaged DNA and apoptosis. Because the ability to regulate apoptosis and repair damage is correlated with increased organismal longevity and survival in many species these particular functions of FOXO transcription factors may be relevant to Sirtl ability to control longevity These experiments in myoblasts show that IGF-I (Lcng.ml') can facilitate apoptosis in the presence of non-a pop to tic doses ofTNF-a (1.25ng.mr\ which appears to depend not only on the upregulation of specific apoptosis genes (potentially downstream of MAPK) but also on the suppression of survival factors IGF-ll and IGFBP-5 which may also lie downstream of MAPK. These studies highlight the complex regulation of cell survival and cell death at the signalling level, as a consequence of interactions of one cytokine, TNF-a, and one growth factor, IGF-I. More information regarding the pathways involved in regulating their expression and activity will be necessary to fully understand the action of these molecules.

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Lunn, Elizabeth Ruth. "Studies on the degeneration and regeneration of neurons to skeletal muscle." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292675.

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Striedinger, Katharine. "Degeneration and regeneration of the retina after trauma: emphasis on gap junctions." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973201126.

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Vargas, Mauricio Enrique. "Control of axon regeneration and wallerian degeneration by the humoral immune system /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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Colavincenzo, Justin. "Myelin debris clearance along the goldfish visual paths during Wallerian degeneration." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21529.

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This study aimed to better understand the clearance of myelin debris during Wallerian degeneration in the goldfish visual paths. Myelin debris was first examined immunohistochemically in the presence or absence of regenerating axons. From these preliminary experiments it was apparent that the clearance of myelin debris was not affected by regenerating axons and that the debris was removed in a differential pattern along the visual pathway. Specifically, in the distal stump of the nerve as well as in the optic tract, myelin debris had been effectively cleared by one-month postoperative, while in the cranial segment of the nerve debris persisted for at least 6 weeks after injury. The differential pattern of myelin debris in the optic nerve and tract was then analyzed qualitatively and quantitatively using thick and thin plastic sections at various time points during regeneration. The results suggested that highly activated peripheral macrophages were responsible for the effective clearance of myelin in the distal nerve stump. In the optic tract a number of cellular properties, including their unique population of astrocytes may have enhanced the rate of debris clearance. By contrast, in the cranial segment of the nerve persistent debris was found both intracellularly in phagosomes and extracellularly, suggesting that the resident phagocytes were deficient in effecting both phagocytosis and emigration. Deficient phagocytosis may be a result of the production of anti-inflammatory cytokines in this region, while the failure to emigrate is most likely due to the rigid network of astrocytes in the nerve.

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Julian, Victoria L. "TIR-1/SARM1 Inhibits Axon Regeneration." eScholarship@UMMS, 2021. https://escholarship.umassmed.edu/gsbs_diss/1155.

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The inability to repair axonal damage is a feature of neurological impairment after injury and in neurodegenerative diseases. Axonal repair after injury depends in part on intrinsic factors. Several genes cell-autonomously regulate both axon regeneration and degeneration in response to injury. Recently, Sarm1 has emerged as a key regulator of neurodegeneration. Whether Sarm1 plays a role in axon regeneration is unknown. In this thesis, I identified a role for the C. elegans homolog of Sarm1, tir-1, as a negative regulator of axon regeneration. Investigating the genes which regulate axon regeneration and degeneration has been hindered by technical difficulties in visualizing and manipulating both of these processes in vivo simultaneously. To circumvent this challenge, I developed a new model of axon injury, where both axon regeneration and degeneration can be monitored in vivo with single neuron resolution in C. elegans. I found that the C. elegans homolog of Sarm1, tir-1, strongly inhibits axon regeneration in response to injury. I found that TIR-1 functions cell-intrinsically and that its subcellular localization is dynamically regulated in response to injury. To regulate both axon regeneration and degeneration after injury, I found that TIR-1 function is determined by interaction with two distinct genetic pathways. Together, this work reveals a novel role for tir-1/Sarm1 in axon regeneration, increases our understanding of the injury response, provides new avenues of investigation for studies of TIR-1/SARM1, and inspires candidate approaches to repair the injured nervous system.

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Vater, Ruth. "The fate of myofibrillar and cytoskeletal proteins during degeneration and regeneration of skeletal muscle." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334746.

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Acosta-Saltos, F. C. "The effects of inflammation on the regeneration and degeneration of axons in the CNS." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1466480/.

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Microglia have neurotoxic and neuroprotective effects. The aim of the current project was to investigate the effects of perineuronal microglial activation on axonal regeneration in adult rats and the effects of prolonged neuroinflammation on foetal mouse brain. In contrast to the PNS, the CNS only displays limited axonal regeneration after injury and little perineuronal inflammation. Inflammation around the cell bodies of axotomised neurons has been demonstrated to promote CNS regeneration. Polyinosinic:polycytidylic acid (Poly I:C) is an inflammatory agent. Following delivery of Poly I:C into the motor cortex and a concomitant C4 dorsal corticospinal tract (CST) injury, rats exhibited more CST axons in the cervical spinal cord and less retraction from the injury site than controls. Following facial nerve axotomy, Poly I:C injections adjacent to the facial nucleus accelerated functional recovery. Viral vectors carrying Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) were injected into motor cortex. GM-CSF virus reduced retraction of corticospinal axons from a spinal cord injury site. Behavioural studies of forelimb movements showed that C4 injury had a greater impact on fine distal movements, particularly reaching and grasping, which are known to be controlled by the CST. Treating rats with GM-CSF virus showed a trend towards improved forelimb sub-movements and significantly aided the reaching function recovery. Perinatal activation of periventricular phagocytes has been suggested to result in white matter damage, causing persistent motor disabilities. Transuterine injections of control or GM-CSF virus targeting the lateral ventricles of mice at gestational day 14, resulted in a widespread virally-transduced cells. Greater numbers of phagocytic and activated microglia were present in the areas of viral transduction. There was increased inflammation in the periventricular white matter. Although, the level of transduction remained relatively constant with increasing time, inflammation decreased, suggesting that GM-CSF toxicity is high before or around birth.

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Chirco, Kathleen Rose. "Mechanisms of pathophysiology and methods for regeneration of the choriocapillaris in age-related macular degeneration." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5438.

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Age-related macular degeneration (AMD) is a devastating disease causing vision loss in millions of people around the world. Loss of choroidal endothelial cells (CECs) is one of the earliest detectable events in AMD, and, because the outer retina relies on the choriocapillaris for metabolic support, this loss may be the trigger for progression to more advanced stages. A crucial event that occurs in the aging choriocapillaris is accumulation of the membrane attack complex (MAC), which may result in complement-mediated CEC lysis, and may be a primary cause for AMD-associated choriocapillaris degeneration. Previous studies have also shown the accumulation of C-reactive protein (CRP) in the choriocapillaris in eyes with AMD and those with the high-risk CFH genotype. While both CRP and the MAC have been implicated in AMD, the precise contribution of these molecules to disease pathophysiology has not been fully elucidated. Furthermore, there is a critical need to better understand the causes for pathologic changes to CECs during AMD and to establish methods for treatment in cases where CECs have already been lost. Therefore, the goals of this thesis are 1) to investigate the role of CRP and complement activation in AMD pathogenesis, and 2) to develop an in vitro method to study CEC replacement strategies. To address these questions, we first evaluated MAC levels in the choriocapillaris in comparison to 19 other tissues throughout the human body in order to determine in which tissues MAC accumulates with normal aging. Interestingly, we found that the choriocapillaris was the only tissue with high levels of the MAC, which was not detected in any of the other tissues. The restricted accumulation of MAC in the choriocapillaris may, in part, explain the specificity of AMD to the neural retina, RPE and choroid, and the relative absence of systemic pathology in this disease. We then studied genotyped human donor eyes and found that eyes homozygous for the high-risk CFH (Y402H) allele had elevated monomeric CRP (mCRP) within the choriocapillaris and Bruch's membrane, compared to those with the low-risk genotype. In order to assess the physiological effects mCRP has on CECs in vitro, CECs and organ cultures were treated with recombinant mCRP. Treatment of CECs with mCRP increased migration rate and monolayer permeability, while organ cultures treated with mCRP exhibited dramatically altered expression of inflammatory genes. Furthermore, in vitro complement activation assays suggest that complement activation on CECs can lead to the dissociation of pCRP into monomers on CECs. Our data indicate that 1) mCRP levels are elevated in individuals with the high-risk CFH genotype, 2) pro-inflammatory mCRP significantly affects endothelial cell phenotypes directly, both in vitro and ex vivo, and 3) MAC formation may be the driving force for accumulation of mCRP in the choriocapillaris. Altogether, this work suggests a role for mCRP in choroidal vascular dysfunction in AMD. Finally, we aimed to develop a reliable method for the production of human choroidal extracellular matrix (ECM) scaffolds to study CEC replacement strategies in an environment that closely resembles the native tissue. Human RPE/choroid tissue was treated sequentially with Triton X-100, SDS, and DNase to remove all native cells. While all cells were successfully removed from the tissue, collagen IV, elastin, and laminin remained, with preserved architecture of the acellular vascular tubes. The ECM scaffolds were then co-cultured with exogenous ECs to determine if the tissue can support cell growth and allow EC reintegration into the decellularized choroidal vasculature. Both monkey and human ECs took up residence in the choriocapillary tubes of the decellularized tissue. These data suggest that our decellularization methods are sufficient to remove all cellular material yet gentle enough to preserve tissue structure and allow for the optimization of cell replacement strategies. Together, these studies provide insight into the mechanism of AMD pathogenesis, suggest potential targets for drug therapies, and develop methods to study the replacement of CECs in more advanced cases of AMD.

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Ohlsson, Marcus. "On optic nerve injury : experimental studies on axonal regeneration in the adult mammalian CNS /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-656-1.

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Lepka, Klaudia Verfasser], Orhan [Gutachter] Aktas, and Dieter [Gutachter] [Willbold. "Iron-sulfur cluster coordinating Glutaredoxins in neuroinflammatory degeneration and regeneration / Klaudia Lepka ; Gutachter: Orhan Aktas, Dieter Willbold." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/1135724490/34.

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Quint, Elizabeth. "An investigation of hair-cell degeneration and regeneration in the guinea-pig inner ear in vivo and in vitro." Thesis, Keele University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337090.

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Singh, Mandeep S. "Regeneration of the retina by stem cell transplantation therapy." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:e1fdf35f-fb1e-42a0-8a81-9876f0151eea.

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One strategy to restore vision in retinitis pigmentosa and related retinal degenerations is by cell replacement. Typically, patients lose vision when the outer retinal photoreceptor layer is lost, and so the therapeutic ideal would be to restore vision at this stage of disease. It is not currently known if a degenerate retina lacking the outer nuclear layer of photoreceptor cells would allow the survival, maturation and reconnection of replacement photoreceptors, as prior studies used hosts with a pre-existing outer nuclear layer at the time of treatment. Here, using a murine model of severe human retinitis pigmentosa at a stage when no host rod cells remain, transplanted rod precursors are shown to reform an anatomically distinct and appropriately polarised outer nuclear layer. A trilaminar nuclear organisation is returned to the rd1 hosts that had only two retinal layers before treatment. The newly introduced rod precursor cells were able to resume their developmental programme in the degenerate host niche to become mature rods with light- sensitive outer segments, and reconnected with host neurons downstream. Visual function, assayed in the same animals before and after transplantation, was restored in animals with zero rod function at baseline. These observations suggest that a cell therapy approach may reconstitute a light-sensitive cell layer de novo and hence repair a structurally damaged visual circuit. Rather than placing discrete photoreceptors amongst pre-existing host outer retinal cells, total photoreceptor layer reconstruction may provide a clinically relevant model to investigate cell-based strategies for retinal repair.

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Duregotti, Elisa. "Neuronal hydrogen peroxide promotes nerve terminals regeneration at neuromuscular junction." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424296.

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The neuromuscular junction (NMJ) is the site of transmission of the electrical impulses from the motor axon terminal to the muscle; the anatomical organization of this highly dynamic system also includes the perisynaptic Schwann cells (PSCs), and therefore the NMJ has to be considered structurally and functionally as a tripartite system. These non-myelinating SCs are intimately associated with the nerve muscle contact and act as dynamic partners at the synapse: they are involved in many physiological functions including the embryonic development and the maintenance of adult NMJs. Moreover, they are able to detect and reciprocally modulate synaptic activity, through the activation of muscarinin and purinergic receptors present on their surface. In addition, non-traditional roles for PSCs in the recovery after nerve injury are being recognized. Following denervation or reduced synaptic activity, PSCs de-differentiate to an earlier developmental stage, becoming “reactive” PSCs, and start proliferating. These reactive PSCs actively participate in the process of nerve degeneration and regeneration: they undergo changes in their gene expression and acquire macrophagic-like activities, thus contributing to the removal of nerve debris as well as to the recruitment of macrophages, by releasing cytokines and chemokines. Moreover, following nerve terminals degeneration, PSCs at denervated end-plates extend long processes that induce and guide nerve regrowth. Given the increasing incidence of non cell-autonomous and dying-back axonopathies - such as amyotrophic lateral sclerosis (ALS) and autoimmune neuropathies - which affect predominantly motor axons terminals, it becomes very important to characterize the crosstalk between degenerating nerve terminals and adjacent PSCs at the NMJ; in particular, the identification of molecular mediators involved in PSCs activation and in nerve terminals regeneration would be crucial for the improvement of therapeutic strategies. This is the general aim of the present thesis and with this purpose in mind, we have adopted an innovative experimental approach, alternative to the traditional cut/crush surgical model employed till now. To confine the nerve damage to the sole motor axon terminal, thus avoiding the involvement of many cell types and inflammatory mediators, we exploited our knowledge on the mechanism of action of two classes of animal presynaptic neurotoxins: α-Ltx, a pore forming toxin of the venom of black widow spiders, and some snake neurotoxins endowed with phospholipase A2 activity called SPANs. Both kinds of neurotoxins induce an acute and highly reproducible motor axon terminal degeneration, which is followed in few days by complete regeneration: thus, this model represents an appropriate and controlled system to dissect the molecular mechanisms underlying de- and re-generation of peripheral nerve terminals, and to define how PSCs contribute to such processes. We have previously shown that nerve terminals exposed to spider or snake neurotoxins degenerate owing to calcium overload and mitochondrial failure. Here, we found that toxin-treated cultured neurons increase their mitochondrial production of hydrogen peroxide (H2O2), which can easily diffuse across membranes, thus acting as a paracrine signal on neighbouring cellS. Indeed, exposure of cultured SCs to H2O2 leads to ERK phosphorylation and to the activation of downstream pathways. The ERK signalling pathway plays a central role in controlling SCs plasticity during nerve repair in-vivo, but so far the molecular mediators responsible for its activation were unknown: neurons-derived H2O2 represents an ideal candidate for this role. In support of this hypothesis, we observed that ERK phosphorylation is reduced in intoxicated neurons-SCs co-cultures pre-incubated with catalase - which converts H2O2 to oxygen and water -, indicating that H2O2 produced inside neurons diffuses to reach nearby SCs, contributing to ERK activation in their cytosol. ERK phosphorylation takes place also in PSCs at intoxicated NMJs in-vivo. To confirm the involvement of H2O2 in promoting nerve regeneration, we performed electrophysiological recordings and immunohistochemistry on intoxicated muscles, and we found that co-injection of catalase together with neurotoxins delays nerve regeneration, confirming the prominent role of H2O2 in promoting NMJ recovery. Injection of the MAP kinase inhibitor PD98059 also impairs nerve repair in a way similar to that observed with catalase, supporting the finding that H2O2 enhances nerve terminals regeneration through the activation of ERK pathway in PSCs
La giunzione neuromuscolare (GNM) costituisce il sito di trasmissione di un impulso elettrico dal terminale del motoneurone alla fibra muscolare; l’organizzazione strutturale di questo sistema altamente dinamico è stata ulteriormente complicata dall’aggiunta delle cellule di Schwann perisinaptiche (CSPs), dando origine al concetto di sistema tripartito. Le CSPs sono cellule di Schwann non mielinizzanti strettamente adese alla zona di contatto tra nervo e muscolo; esse partecipano attivamente a molte funzioni fisiologiche della GNM, come il suo sviluppo embrionale ma anche il corretto mantenimento di GNMs adulte. Esse sono inoltre in grado di percepire e modulare l’attività sinaptica, mediante l’attivazione di recettori muscarinici e purinergici presenti sulla loro superficie. Studi più recenti hanno dimostrato che le CSPs sono coinvolte nei processi di recupero che hanno luogo in risposta ad un danno nervoso; in seguito a denervazione o a ridotta attività sinaptica, le CSPs de-differenziano, diventando CSPs “reattive”, ed iniziano a proliferare. Queste CSPs reattive partecipano attivamente ai processi di degenerazione e rigenerazione nervosa: esse subiscono variazioni nella loro espressione genica e acquisiscono attività simil-macrofagiche, contribuendo alla rimozione dei detriti neuronali e reclutando fagociti in seguito al rilascio di citochine e chemochine. Inoltre, in seguito alla degenerazione dei terminali nervosi, le CSPs presenti alle placche motrici denervate estendono lunghi processi citosolici in grado di indurre e guidare la ricrescita neuronale. Considerando la crescente incidenza di malattie neurodegenerative che inizialmente interessano in maniera selettiva i terminali dei motoneuroni – quali la SLA e le neuropatie autoimmuni -, sarebbe senz’altro utile caratterizzare in maniera più approfondita il crosstalk tra terminali nervosi in degenerazione e le adiacenti CSPs. In particolare, l’identificazione di mediatori molecolari coinvolti nell’attivazione delle CSPs e nel processo di rigenerazione nervosa potrebbe rivelarsi cruciale per lo sviluppo di nuovi approcci terapeutici. A tale scopo, abbiamo adottato un approccio sperimentale innovativo, alternativo al cut/crush del nervo sciatico tradizionalmente utilizzato fino ad oggi. Al fine di effettuare un danno localizzato ai soli terminali nervosi, evitando il coinvolgimento di molti tipi cellulari e mediatori dell’infiammazione come accade nel corso della degenerazione Walleriana, abbiamo deciso di sfruttare il meccanismo d’azione di due classi di neurotossine presinaptiche animali: α-Latrotoxin, una tossina formante poro presente nel veleno dei ragni del genere Latrodectus, ed alcune neurotossine di serpente dotate di attività fosfolipasica, denominate SPANs. Entrambi i tipi di neurotossine inducono un’acuta e altamente riproducibile degenerazione dei terminali nervosi dei motoneuroni, seguita entro pochi giorni da una rigenerazione completa: l’azione di tali neurotossine rappresenta quindi un sistema appropriato e controllato per esaminare i meccanismi molecolari alla base della degenerazione e rigenerazione nervosa, come anche il contributo delle CSPs a tali processi. Abbiamo precedentemente dimostrato che i terminali nervosi esposti ad α-Ltx e SPANs deegenerano a causa di un eccessivo influsso di calcio nel citosol, che a sua volta induce un danno mitocondriale. In questo lavoro, abbiamo dimostrato che neuroni primari intossicati aumentano la produzione di H2O2 a livello mitocondriale: il perossido di idrogeno è una molecola stabile e diffusibile attraverso membrane lipidiche, e potrebbe perciò agire come segnale paracrino su cellule adiacenti. Infatti, l’esposizione di cellule di Schwann (CSs) primarie in coltura a basse concentrazioni di H2O2 induce la fosforilazione di ERK, con la conseguente attivazione di pathways a valle. È stato recentemente dimostrato che la via di ERK gioca un ruolo fondamentale nel controllo della plasticità delle CSs durante la rigenerazione nervosa in vivo, ma fino ad oggi i mediatori molecolari responsabili per l’attivazione di tale pathway non sono ancora stati identificati: il perossido di idrogeno prodotto dai neuroni in degenerazione costituisce un buon candidato per tale ruolo. In supporto a tale ipotesi, abbiamo osservato che il livello di fosforilazione di ERK è ridotto in co-colture di neuroni e CSs intossicate e pre-incubate con catalasi, che converte rapidamente il perossido di idrogeno in ossigeno ed acqua: ciò conferma che il perossido di idrogeno prodotto dai neuroni diffonde effettivamente nel mezzo extracellulare fino a raggiungere le vicine CSs, nelle quali induce l’attivazione della via di ERK. Tale attivazione è riscontrata anche nelle CSPs alle GNMs intossicate in vivo. Per confermare il coinvolgimento del perossido di idrogeno nell’induzione della rigenerazione nervosa, abbiamo effettuato registrazioni elettrofisiologiche ed esperimenti di immunoistochimica, ed entrambi gli approcci sperimentali hanno dimostrato che in la somministrazione di catalasi in vivo ritarda il processo di rigenerazione nervosa in muscoli intossicati. Inoltre, il pre-trattamento con un inibitore della via di ERK - PD98059 – rallenta la il recupero dall’intossicazione con una cinetica molto simile a quella osservata in presenza di catalasi, supportando l’idea che in effetti il perossido di idrogeno promuova la rigenerazione nervosa attraverso l’attivazione della via di ERK nelle CSPs

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Tedesco, Erik. "Study of the nerve terminal regeneration in neuromuscular junction intoxicated with different presynaptic neurotoxins." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3421595.

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The neuromuscular junction (NMJ) is a fundamental structure in biology and its organization have been complicated by the addiction of perisynaptic Schwann cells (PSCs), leading to the tripartite system concept. PSCs are the glia of the NMJ and they are implicated in its recovery after damage. Indeed, PSCs dedifferentiate upon nerve terminal (NT) damage, remove NT debries and protrude prolongations to guide reinnervation. Some PSCs activation mediators have been found (ATP, ACh) but we hypothesized that also arachidonic acid and its derivates could lead to PSCs activation. Nerve damage models used till now provide a non controllable system since they lead to Wallerian degeneration, a degenerative/inflammatory process. The intramuscular injection of presynaptic neurotoxins (α-LTX and SPANs), provoking damage limited to the NTs, represents our experimental model. Since SPANs leads to NTs degeneration via different action, to unravel Ca2+ influx relative contribution we performed a side-by-side comparison with α-LTX, which provoke degeneration through massive Ca2+ influx. All analyzed parameters are similar for the two neurotoxin classes. This indicates that Ca2+ overloading plays a major role in NTs degeneration induced by SPANs. No differences were observed in NTs degeneration/regeneration kinetic between fast (EDL) and slow muscle (soleus). α-LTX provoke a synchronous degeneration of NTs in agreement with muscle functional assay (DAS assay). NTs degeneration induced by a SPAN such as βBtx present a “patch-like” pattern and DAS score do not parallels immunohistological observations. A difference in PSCs behaviour was observed between α-LTX-injected and denervated EDL. A decrease in signal intensity of S100-labeled PSCs was observed after α-Ltx treatment, indicating their activation, but no prolongations were observed except in denervated sample. To characterize PSCs behavior we extended the analysis to Nestin and Glial Fibrillaric Acidic Protein (GFAP), that label only activated PSCs. No differences between control and intoxicated NTs were observed. Considering that PSCs acquire macrophagic-like activity and possess receptors sensing pathogen-associated molecular patterns we wondered if formylated peptides and mitochondrial DNA, coming from degenerating mitochondria, could activate PSCs. We tried to address this question on Schwann Cells primary culture with different approaches but, up to now, the results are not conclusive due to experimental problems.
La giunzione neuromuscolare (GNM) e’ una struttura fondamentale in biologia e la sua organizzazione e’ stata recentemente complicata dall’ aggiunta delle cellule di Schwann perisinaptiche (CSP), portando al concetto di sistema tripartito. Le CSP rappresentano la glia della GNM e sono coinvolte nel suo recupero in seguito a danno. Infatti, le CSP dedifferenziano in seguito a danno al terminale nervoso (TN), rimuovono i detriti derivanti della sua degenerazione e protrudono una serie di prolungamenti che guidano la reinnervazione. Alcuni mediatori implicati nell’attivazione dell CSP sono stati individuati (es. ATP, ACh) ma noi ipotizziamo che anche l’acido arachidonico e I suoi derivati possano portare all’attivazione dell CSP. I modelli di danno al nervo usati fino ad ora forniscono un sistema non controllabile dal momento che portano alla degenerazione Walleriana, un processo degenerativo e infiammatorio. L’iniezione intramuscolare di tossine presinaptiche (α-LTX and SPANs), provocando un danno limitato al solo TN, rappresenta il nostro sistema sperimentale. Dal momento che le SPANs conducono alla degenerazione del TN mediante differenti azioni, per determinare il contributo relativo dell’influsso di Ca2+ abbiamo effettuato una comparazione con α-LTX, la quale provoca degenerazione del TN attraverso un massiccio ingresso di Ca2+. Tutti I parametri analizzati sono simili per le due classi di neurotossine. Questo indica che il sovraccarico di Ca2+ gioca un ruolo di rilievo nella degenerazione del TN indotta da SPANs. Non sono state osservate differenze nella cinetica di degenerazione/rigenerazione dei TN tra muscoli veloci (EDL) e lenti (soleo). α-LTX provoca una degenerazione sincrona in completo accordo con i dati derivanti dal saggio di funzionalita’ muscolare (saggio DAS). La degenerazione dei TN indotta da SPANs, nel caso specifico βBtx, presentano un motivo a chiazze e i dati derivati dal saggio DAS non correlano con le osservazioni immunoistologiche. Una differenza nel comportamento delle CSP e’ stato osservato tra EDL iniettati con α-LTX e denervati. Una diminuzione dell’intensita’ del segnale delle CSP marcate con S100 e’ stato osservata dopo trattamento con α-Ltx e denervazione, indicandone l’attivazione, ma non e’ stata osservata la protrusione di prolungamenti se non nei muscoli denervati. Al fine di caratterizzare meglio questo peculiare comportamento dell CSP, abbiamo esteso l’analisi ad marker di attivazione delle CSP, quali Nestina and Glial Fibrillaric Acidic Protein (GFAP). Non sono state osservate differenze tra i controlli e i campioni intossicati. Considerando che le CSP acquisiscono un’attivita’ simil-macrofagica in seguito ad attivazione e possiedono recettori in grado di individuare pattern molecolari associati a patogeni, ci siamo chiesti se peptidi formilati e DNA mitocondriale, derivanti dai mitocondri in degenerazione, possano attivare le CSP. Abbiamo provato a testare con diversi approcci la nostra ipotesi su colture primarie di cellule di Schwann ma, a causa di problemi sperimentali, i risultati non sono al momento conclusivi.

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18

Griffith, John Wylie. "Degeneration, atavism, survival, and regeneration : anthropological and zoological doctrines in some works of Joseph Conrad, H.G. Wells and D.H. Lawrence." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316801.

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19

Rodrigues, Pinto Ricardo Pedro Ferreira. "Isolation and phenotypic characterisation of human notochordal cells : implications for the development of cell-based therapies for intervertebral disc degeneration." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/isolation-and-phenotypic-characterisation-of-human-notochordal-cells-implications-for-the-development-of-cellbased-therapies-for-intervertebral-disc-degeneration(8d5cbfdd-edd0-458c-a048-554f6a2c830b).html.

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Back pain is a highly prevalent condition whose pathogenesis is associated with intervertebral disc (IVD) degeneration. Degeneration is driven by abnormal cell biology, particularly within the IVD’s inner core, the nucleus pulposus (NP). In recent years, there has been an ever-increasing search for cell-based therapies aimed at correcting the cell biology and thus repairing/regenerating the degenerate IVD. The success of these novel therapies, however, requires a thorough understanding of IVD development and of the phenotype of its cells. The embryonic, foetal and juvenile NP is populated by large vacuolated notochordal cells that with skeletal maturity are replaced by smaller NP cells. Since notochordal cells have been shown to display protective and anabolic roles in the IVD their loss in humans has often been suggested to initiate the degenerative process. As such, a detailed understanding of notochordal cells and their regulatory pathways may help identify factors involved in IVD homeostasis and aid the development of novel cell-based therapies targeting IVD degeneration. The study of human notochordal cells has, however, been hindered by ethical, logistical and technical difficulties in obtaining suitable samples and, as such, the human notochordal cell phenotype is, to date, unknown, constituting a major limitation in the field. The work presented here was conducted with the objective of developing a methodology to isolate human developing notochordal cells (NP progenitors) from adjacent sclerotomal cells (annulus fibrosus and vertebral body progenitors), to characterise the notochordal cell phenotype and identify potential factors involved in notochordal cell biology. Initially, human embryonic and foetal spines were characterised to assess their suitability as a source of notochordal cells and to identify a notochord-specific marker that could be used to isolate notochordal cells for microarray studies. The human developing spine contained large vacuolated notochordal cells in all stages analysed (3.5-18 weeks post-conception (WPC)) that specifically expressed KRT8, KRT18 and KRT19 at all stages and CD24 between 5.5-18 WPC. KRT18 and CD24 were independently used to label notochordal cells (7.5-14 weeks post-conception) and separate them from sclerotomal cells. Methodologies were developed to allow extraction of RNA of sufficient quality for microarray analysis from fixed, permeabilised (in the case of KRT18) and/or, labelled and sorted cells (CD24). Microarray analysis identified and real-time qPCR and, for some markers, immunohistochemistry, validated GRB14, SLC19A1, FGF10, ADORA3, TBXA2R, CDH6, ANPEP, CD69, CD24, RTN1, PRPH, MAP1B, ISL1 and CLDN1 as human notochordal cell markers. Ingenuity pathway analysis was performed to investigate the pathways/networks and upstream regulators and downstream effectors of notochordal cells. Inhibition of inflammation and angiogenesis were identified as relevant to notochordal cell biology, function and, possibly, to the known protective and anabolic role notochordal cells display in the IVD. Notochordal marker gene expression was identified in adult NP tissue, and negatively correlated with degeneration. Proteins encoded by ADORA3 and MAP1B were expressed by a proportion of adult NP cells, suggesting the presence of notochord-derived cells in the adult NP.Importantly, this is the first study to detail a methodology and successfully isolate human notochordal cells. Such methodology has the potential to be used to culture and investigate the biology of viable human notochordal cells (CD24+ve). Future studies aimed at developing cell-based therapies for IVD degeneration could also use these identified markers to assess appropriate stem cell differentiation to notochordal cells.

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20

周智豪 and Chi-ho Chau. "Neural glycosaminoglycans and their effects on post-traumatic regrowthof sciatic nerves in adult guinea pigs." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31236625.

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21

Khan, Shahnaz. "The effect of the intervertebral disc microenvironment on disc cell and mesenchymal stem cell behaviour : implications for disc degeneration and regeneration." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/the-effect-of-the-intervertebral-disc-microenvironment-on-disc-cell-and-mesenchymal-stem-cell-behaviour-implications-for-disc-degeneration-and-regeneration(b5629a75-4cb0-45d8-affb-2b936d9408e1).html.

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Intervertebral disc (IVD) degeneration is associated with low back pain (LBP). It has been suggested that changes in the IVD physio-chemical microenvironment (i.e. hypoxia, reduced nutrient and acidic conditions) may lead to disc degeneration. Studying the response of human nucleus pulposus (NP) cells to these conditions could establish the causal relationship between IVD microenvironment and aberrant cellular behaviour, characteristic of disc degeneration. Human bone marrow mesenchymal stem cells (BM-MSCs) are a promising cell population for disc regeneration. However, knowledge of their survival and functioning in the microenvironment of the IVD is still lacking. Moreover, in vitro co-culture model studies that are used to study MSC/disc cell interaction, also need to consider the effect of the microenvironment on cellular responses. BM-MSCs and degenerate NP cells were cultured alone or co-cultured in monolayer under hypoxia (2%O2), reduced nutritional (2% serum or/and 5mM glucose) and acidic (moderate pH 6.8 or severe pH 6.5) conditions alone or in combination for 7 days. Cell viability, proliferation, gene and protein expression was assessed. Degenerate NP cells and BM-MSCs maintained good cell viability under all conditions. Both cell types demonstrated overall similar proliferation and gene and protein responses under the majority of the conditions and combinations studied. Hypoxia promoted aggrecan and versican matrix biosynthesis in both cell types. Nutrient deprived and moderate acidic conditions (pH 6.8) inhibited proliferation of both cell types. Interestingly the combination of hypoxia with these conditions showed a protective effect in modulating cell proliferation. These results imply that hypoxia may be beneficial in some instances. Nutrient deprived conditions had a relatively minor effect on degenerate NP cell gene and protein expression but these conditions specifically inhibited VCAN expression in BM-MSCs. The combination of hypoxia with these conditions increased or restored VCAN expression. Interestingly the combination of hypoxia with reduced glucose conditions increased aggrecan and versican matrix biosynthesis in both NP cells and BM-MSCs. The combination of hypoxia and complete nutrient deprived conditions (both reduced serum and reduced glucose) impaired ACAN, VCAN and PAX-1 gene and aggrecan and versican protein expression in degenerate NP cells implicating disc hypoxia and complete nutrient deprived combined microenvironment in accelerating degenerate changes in NP cells. In contrast, these conditions showed no such detrimental effects on BM-MSC gene and protein expression. pH 6.5 was critical for both cell types proliferation and ACAN and VCAN gene expression suggesting that severe acidic conditions may exacerbate degenerative changes and be inhibitory for implanted MSCs. Finally, a combination of hypoxia, complete nutrient deprived and moderate acidic conditions, reduced cell proliferation without affecting the gene expression profile of both cell types. IVD-like physio-chemical microenvironmental conditions also appeared to influence differentiation of BM-MSC and modulation of degenerate NP cell phenotype observed during co-culture. Noticeably hypoxia, reduced serum or reduced glucose conditions stimulated BM-MSC differentiation and modulation of degenerate NP cell phenotype. Hypoxia also increased or recovered changes at gene expression level in both BM-MSCs and degenerate NP cells under nutrient deprived (reduced serum or/and reduced glucose) conditions during co-culture. Degenerate NP cell and BM-MSC co-culture also showed noticeable increase in aggrecan and versican biosynthesis under hypoxia and reduced glucose combine conditions, implicating these in improving the co-culture responses. Severe pH condition alone, pH 6.8 in combination with hypoxia and finally all IVD-like physio-chemical conditions together compromised co-culture responses. Such results imply that IVD-like physio-chemical microenvironmental conditions may influence MSC based regenerative outcomes. This work has increased our understanding about the influence of disc harsh microenvironment on degeneration and regeneration processes.

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22

Caramoy, Albert. "Ultrastruktur der Degeneration und Regeneration des Nervus facialis nach direkter und verzögerter Nervennaht bei der Ratte : eine elektronenmikroskopische Studie des peripheren Nervs /." Köln, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000264349.

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23

陳博文。 and Pok-man Chan. "Cloning of hamster GAP-43 to study the expression and regulation of GAP-43 mRNA in the retina during degeneration and regeneration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31220423.

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24

Chan, Pok-man. "Cloning of hamster GAP-43 to study the expression and regulation of GAP-43 mRNA in the retina during degeneration and regeneration /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2063299X.

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25

Eberle, Dominic. "Cell transplantation and gene therapy approaches for the treatment of retinal degenerative disorders." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-102054.

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Photoreceptors are of prime importance for humans, since vision is one of the most important senses for us. In our daily life, where nearly every action is dependent on visual input, an impairment or a loss of eyesight leads to severe disability. With a non-syndromic prevalence of 1:4000, retinitis pigmentosa, a collective term for a group of inherited retinal eye diseases, represents, together with age-related macula degeneration, one of the main causes for visual impairment and blindness in industrialized countries. The dominant reason for vision loss is, in both cases, the irreversible loss of photoreceptor cells located in the outer nuclear layer of the retina. To date, no effective treatment is available to preserve or regain visual function in affected patients. Recent promising strategies for new retinal therapeutical approaches focus on one hand on the development of gene therapies, where an introduced wild-type allele compensates a mutated gene, and on the other hand on cell therapies, where stem or photoreceptor precursor cells (PPCs) are transplanted to the sub-retinal space to replace degenerated host photoreceptors. The current study is subdivided into three parts, addressing the issue of non-reversible photoreceptor cell loss due to retinal degenerative diseases by investigating in the first two parts new qualitative as well as quantitative approaches in the field of retinal cell therapy, while in the third part an ocular gene therapeutical approach targeting prominin-1, a gene involved in retinal degenerative disorders, was investigated. Briefly, this study shows in the first part, a significant enhancement of the integration rate of PPCs in wild-type host retinas, achieved by pre-transplantational sorting, using the recently discovered PPC - specific cell surface marker CD73. This sets another step further towards retinal cell therapy by increasing the effectiveness of such treatment. Next to this quantitative approach, it is also shown that the quality of transplanted photoreceptor precursor cells is comparable to native photoreceptors by demonstrating, that an indispensable prerequisite of every photoreceptor cell, the outer segment, is developed by transplanted PPCs after proper integration. Importantly, transplanted PPCs develop native outer segments even when not integrated in the host tissue but located in the sub-retinal space, as it is predominantly observed after transplantation into severely degenerated retinas. These results substantiate the feasibility of cell therapeutical treatment of severely degenerated retinas. At the end of this part, it is demonstrated, that outer segments are not formed properly by PPCs transplanted to the vitreal side of the retina. This suggests an influence of signaling molecules, presumably secreted by retinal pigment epithelial cells into the sub-retinal space, on transplanted PPC final differentiation. Since intensive research is done to differentiate stem cells into PPCs for cell therapeutical transplantation, these results may contribute significantly to this research by demonstrating, that factors secreted by the retinal pigment epithelium might play a crucial role for successful stem cell to PPC differentiation. The last part of my work investigates a gene therapeutical approach to cure inherited retinal degenerative diseases. One gene, where reported mutations cause retinal degeneration in humans is prominin-1, a protein expressed at cell membrane evaginations in a variety of cell types. Interestingly, the prominin-1 knock-out mouse is characterized exclusively by disorganized photoreceptor outer segment formation and progressive retinal degeneration. Successful delivery of a wild-type form of mouse prominin-1 using adeno-associated viral vector transfer, into the photoreceptors of prominin-1 - deficient mice is demonstrated. The divergent results show on one hand a rescue of the thickness of the photoreceptor outer nuclear layer on a short time period (3 weeks post treatment), and on the other hand long-term data (8-10 weeks post treatment) suggests histologically as well as functionally a negative effect on treated photoreceptors. This might be due to effects caused by an over-expression of prominin-1 and will be investigated in future studies. In conclusion, distinct and important investigations were made which contribute significant puzzle pieces to new cell- as well as gene therapeutical approaches for the treatment of retinal degenerative disorders.

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26

Leiva, Rodríguez Tatiana. "Investigation of the role and modulation of autophagy for neuroprotection and nerve regeneration using models of peripheral nerve injury." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/667461.

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Lesiones en el nervio periférico causan una disrupción axonal que puede producir una neurodegeneración retrograda. Las neuronas axotomizadas sufren una serie de cambios fenotípicos a nivel molecular y celular, algunos de ellos llamados mecanismos endógenos de neuroprotección, que promueven la supervivencia neuronal. En estos mecanismos se incluyen la respuesta de proteína desplegada (UPR) y la autofagia. La intensidad y el tiempo de respuesta de la neurona vienen influenciados por la severidad de la lesión, la distancia respecto al soma, el tipo de neurona y la edad. Sin embargo, cuando la lesión es muy proximal al soma, como es el caso de la lesión de avulsión de raíz de nervio periférico (RA), los mecanismos endógenos de neuroprotección pueden no ser activados contribuyendo a la neurodegeneración. Por este motivo creemos que la corrección o la potenciación de los mecanismos endógenos podrían ser efectivos para la neuroprotección y la regeneración. Primero caracterizamos el estado de flujo autofágico después de PNI in vivo y encontramos un bloqueo de estas vías, alteraciones en proteínas relacionadas con microtúbulos y proteínas de tráfico vesicular a los 5-7 días posteriores a la lesión. Posteriormente, modelamos algunos eventos concomitantes asociados con las alteraciones de la autofagia y en el citoesqueleto en el modelo in vitro. Además, analizamos la respuesta temporal de la autofagia y el citoesqueleto in vitro. Estos resultados, revelaron que la neurodegeneración podría ocurrir debido a la alteración inicial de los microtúbulos después del bloqueo de la autofagia. Además,estas alteraciones del citoesqueleto aumentan la astrogliosis y la muerte de MN in vivo. Finalmente, exploramos el papel de la potenciación de la autofagia. El análisis del curso temporal de la inducción de autofagia farmacológica usando rapamicina reveló ser neuroprotector solo como un pretratamiento antes de la lesión de RA. Además, la activación de la autofagia mediada por la sobreexpresión de ATG5 dio como resultado una preservación de MN acompañada de una mejora en la vía secretora y el flujo autofagico. Resultados previos demostraron que BiP neuroprotegía frente a RA y que su expresión se veía disminuida en las motoneuronas degeneradas. Considerando su relación con la autofagia, nuestro objetivo fue aclarar los mecanismos de neuroprotección mediante la proteómica. Descubrimos que la sobrexpresión de GRP78/BiP promovía la reducción de proteínas mitocondriales mediante la inducción de la mitofagia. Esta activación era dependiente de IP3R y PINK1 Finalmente, considerando que una terapia efectiva después de la lesión de nervio periférico promueve el crecimiento axonal y la regeneración nerviosa, exploramos si la potenciación de la autofagia podría ser pro-regenerativa. Finalmente, considerando que una terapia efectiva después de la PNI debería promover el rebrote axonal y la regeneración nerviosa, exploramos si la estimulación autofagia también podría ser pro-regenerativa. Descubrimos que la autofagia mediada por SIRT-1/ HIF1α promueve el crecimiento de neuritas in vitro. Además, la potenciación de la autofagia mediante la sobrexpresión de ATG5 o SIRT1 acelera la recuperación funcional y el crecimiento axonal después de la lesión. Estos hallazgos sugieren que la corrección o la potenciación de los mecanismos endógenos como la autofagia, pueden ser una terapia eficaz para aumentar la supervivencia de las motoneuronas desconectadas y mejorar el crecimiento axonal después de las lesiones de nervio periférico.
Severe peripheral nerve injury (PNI) cause axonal disruption and may produce retrograde neurodegeneration. Axotomized neurons undergo a series of phenotypic changes at the molecular and cellular levels, some of them called endogenous mechanisms of neuroprotection, that promote neuronal survival that includes the unfolded protein response (UPR), the heat-shock response, the autophagy pathway, the ubiquitin-proteasome system, chaperone, the endoplasmic reticulum (ER)-associated degradation machinery (ERAD) and the antioxidant defence. The intensity and time course of the neuronal response are mainly influenced by the severity of the injury, distance of the lesion to cell body, type of neuron and age. However, when the injury is proximal to the soma, such in the case of peripheral nerve root avulsion (RA), the endogenous mechanisms of neuroprotection might not be properly activated contributing to neurodegeneration. We reasoned that the correction or potentiation of these mechanisms might be effective for neuroprotection. We first characterize the state of autophagy flux after PNI in vivo and found a blockage of these pathway, alterations in microtubule related proteins and vesicle trafficking proteins at 5-7 days post-injury Subsequently, we modelize some concomitant events associated with autophagy failure such as cytoskeleton abnormalities in in vitro model. Furthermore, we analyse the time course response of autophagy and cytoskeleton in vitro. These revealed that neurodegeneration might occur due to initial microtubule alteration followed autophagy blockage. These cytoskeleton alterations increase astrogliosis and MN death in vivo. Finally, we explored the role of autophagy potentiation. Time-course analysis of pharmacological autophagy induction using rapamycin revealed to be neuroprotective only as a pre-treatment before RA injury. In addition, autophagy activation mediated by ATG5 overexpression resulted in a MN preservation accompanied by improved internal trafficking and autophagy flux. Previous data demonstrated neuroprotective capacities mediated by GRP78/BiP overexpression that it has been found downregulated in degenerated MNs after the lesion. Considering its relationship with autophagy, we aimed to clarify the mechanisms of these neuroprotection by proteomic analysis. We discovered that GRP78/BiP overexpression induces the downregulation of mitochondrial proteins by the induction of mitophagy. In this activation of mitophagy by GRP78/BiP is implicated IP3R and PINK1 Finally, considering that an effective therapy after PNI should promote axonal regrowth and nerve regeneration, we explored if autophagy stimulation might be pro-regenerative as well. We did so by overexpressing ATG5 or by genetic and pharmacological activation of SIRT1. We discovered that autophagy mediated by SIRT-1/HIF1α promotes neurite outgrowth in vitro. In addition, autophagy potentiation by ATG5 or SIRT1 overexpression enhances functional recovery and axonal growth after the lesion. Overall, these findings suggested that correction or potentiation of endogenous mechanisms such as autophagy may be an effective therapy to increase the survival of disconnected MNs and enhanced axonal regrowth after the peripheral nerve injuries.

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27

Zeber, Anne Christine [Verfasser], and Robert-Benjamin [Akademischer Betreuer] Illing. "Lesion-dependent expression and redistribution of neuronal and glial markers in the central auditory system after cochlear ablation: Their compartmental localization and association to degeneration and regeneration in the anteroventral cochlear nucleus = Läsionsabhängige Expression und Umverteilung von neuronalen und glialen Markern im zentralen auditorischen System nach Cochleotomie: Ihre kompartimentelle Lokalisation und Assoziation zu Degeneration und Regeneration im anteroventralen Nucleus cochlearis." Freiburg : Universität, 2011. http://d-nb.info/1123459908/34.

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28

Albuquerque, Tereza Cristina Pessoa de. "Ação de antiinflamatorios não-esteroides na degeneração/regenação de fibras musculares distroficas de camundongos mdx." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317769.

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Orientador: Maria Julia Marques
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Em fibras musculares distróficas de camundongos mdx e na distrofia muscular de Duchenne (DMD), a deficiência da distrofina provoca lesão do sarcolema e degeneração muscular. Esta deficiência está associada a alterações na estabilidade do sarcolema e aumento dos níveis intracelulares de cálcio, que podem provocar mionecrose. O mecanismo exato que provoca a lesão da membrana e a mionecrose são desconhecidos. Uma das hipóteses é que a resposta inflamatória endógena pode aumentar a lesão do sarcolema devido à ausência da distrofina. O processo inflamatório está associado com a regeneração muscular e com o reparo tecidual. Antiinflamatórios não-esteróides (AINE) podem reduzir a inflamação que ocorre como conseqüência de lesão muscular através da inibição das ciclo-oxigenases, provocando redução da síntese de prostaglandinas. Estudos anteriores mostraram que houve atraso da regeneração muscular após a utilização de AINE. Neste estudo, foi verificado se os AINE naproxeno e nimesulida reduzem a mionecrose no camundongo mdx, um dos modelos experimentais da DMD. Camundongos mdx (n= 48) com 21 dias de idade receberam injeções intraperitoneais de naproxeno (10 mg/kg de peso corporal) ou de nimesulida (25 mg/kg de peso corporal) durante 15 ou 30 dias consecutivos. Camundongos mdx não tratados receberam injeção intraperitoneal de solução salina. Para a observação e contagem de fibras em degeneração, três animais de cada grupo receberam injeção intraperitoneal de azul de Evans (AE), marcador que indica alterações de permeabilidade do sarcolema. Secções transversais dos músculos esternomastóide (STN) e tibial anterior (TA) foram coradas com hematoxilina-eosina. A secção total transversa foi dividida em área de infiltrado inflamatório, com fibras em estágios iniciais de regeneração (áreas INFL/REG), e áreas com fibras em estágio avançado de regeneração (áreas REG). Estas áreas foram expressas como porcentagens da área seccional transversa total. O número de fibras regeneradas (fibras com núcleo central), fibras com núcleo periférico e fibras em degeneração (positivas ao corante AE) foram quantificadas. O naproxeno mostrou-se mais efetivo que a nimesulida na diminuição da mionecrose, influenciando de maneira diferenciada os ciclos de degeneração/regeneração de músculos distróficos, principalmente quando utilizado nos estágios iniciais destes ciclos. Concluímos que a utilização de inibidores da produção de prostaglandinas não prejudica a regeneração muscular de camundongos mdx, podendo ser uma alternativa para o tratamento de miopatias, especialmente se associada a outros fármacos de ação mais direta na proteção à mionecrose
Abstract: In dystrophin-deficient fibers of mdx mice and in Duchenne muscular dystrophy (DMD), the lack of dystrophin leads to sarcolemma breakdown and muscle degeneration. The lack of dystrophin is associated with changes in membrane stability and increased levels of calcium in the muscle fiber, which leads to myonecrosis. The exact mechanism determining the sarcolemmal lesion and myonecrosis is unknown. One hypothesis is that the endogenous inflammatory response exacerbates the muscle fiber membrane damage due to the lack of dystrophin. Inflammation has also been associated to muscle regeneration and repair. Non-steroidal anti-inflammatory drugs (NSAID) can reduce inflammation following injury by inhibiting cyclooxygenase and leading to a reduction in prostaglandin synthesis. Previous experimental studies have indicated delayed muscle regeneration after NSAID. In this work, we verified the effects of the cyclooxygenase inhibitors, naproxen and nimesulide, on the extent of myofiber necrosis in the mdx mice model of DMD. Mdx mice (n=48) at 21 days after birth received daily intraperitoneal injections of naproxen (10 mg/kg body weight) or nimesulide (25 mg/kg body weight) for 15 or 30 days. Untreated mdx mice were injected with saline. To measure muscle fiber damage, some mice were injected with Evans blue dye (EBD; n=3), a marker of sarcolemmal lesion. Cryostat cross-sections of the sternomastoid (STN) and tibialis anterior (TA) muscles were stained with hematoxylin and eosin. The whole cross-sectional area of the muscles was divided into areas of inflammatory infiltrate with early regenerating fibers (INFL/REG areas) and areas with late regenerated fibers (REG areas). These areas were expressed as a percentage of the total cross-section area. The number of regenerated fibers (central nucleated fibers), fibers with peripheral cell nuclei and degenerated fibers (positive to EBD) was counted. Naproxen was more effective than nimesulide in decreasing myonecrosis. We concluded that the use of prostaglandin inhibitors does not impair muscle regeneration in the mdx mice. They could be useful therapeutic alternatives in the treatment of DMD, but should be accompanied by other strategies directed against muscle degeneration
Mestrado
Anatomia
Mestre em Biologia Celular e Estrutural

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29

Barbosa-Souza, Valéria. "Mediação da osteopontina na mionecrose e regeneração muscular após envenenamento por Bothrops lanceolatus." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/310755.

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Orientador: Maria Alice da Cruz Hofling, Albetiza Lôbo de Araújo
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Os acidentes por serpentes venenosas podem causar alterações locais graves e de rápido desenvolvimento. O veneno de Bothrops lanceolatus (VBL) contém, dentre outras toxinas, metaloproteinases hemorrágicas e pouco hemorrágicas (SVMPI e SVMPIII) e atividade pró-trombina que causam inflamação (vias das ciclooxigenases-COX e lipoxigenases), alterações hemostáticas e degenerativas. O veneno de Bothrops lanceolatus (100 ?g/100 ?l) foi injetado no gastrocnêmio de ratos para investigar a patogênese da mionecrose (1,3,6,18 horas 1, 2 dias) e regeneração muscular (3,7,14 e 21 dias) ocasionada pelo envenenamento através de análise histológica quantitativa (medida do menor diâmetro 1 hora e 21 dias pós- VBL) e imunohistoquímica para a osteopontina (OPN), citocina inflamatória, quimiotática, com sítios de ligação para integrinas de matriz e células. A medida da expressão dos macrófagos residentes (CD68+) e dos macrófagos migrantes (CD163+), de myoD e miogenina, membros da família de fatores transcricionais miogênicos foi feita com o objetivo de correlacionar com a expressão da OPN nos diferentes estágios patológicos (n=6/período) ao longo do período experimental. Os grupos controles foram injetados com PBS (100 ?l). O envenenamento produziu hemorragia local, edema, infiltrado neutrofílico e macrofágico e desorganização das bainhas perimisiais de tecido conjuntivo, após 48 horas. As fibras mionecróticas apresentavam-se em número moderado. Aos 3 dias, havia focos de deposição de colágeno (tipo I) no meio dos quais se viam mioblastos. O número de macrófagos CD68+ atingiu o máximo às 24 horas, e manteve-se significativamente maior que nos grupos controles até aos sete dias. A expressão de OPN foi significativamente maior das 6 horas aos 3 dias e dos 7 aos 14 dias, sendo expressa em fibras musculares, macrófagos, mioblastos, miotubos e fibroblastos. Não foi obtida marcação para anti-myoD; a expressão de miogenina, que tipicamente é nuclear, foi observada também no citoplasma de mioblastos e miotubos até o 70 dia (pico), sendo sua expressão somente nuclear aos 14 dias. A retenção de miogenina no citoplasma tem sido interpretada como mecanismo de retardo na diferenciação, já que a presença no núcleo é necessária para o seu papel regulador transcricional. Aos 21 dias as fibras regeneradas, com núcleo central, não haviam atingido o tamanho das fibras maduras intactas (VBL) e dos controles. Considerando que as SVMPs e a enzima com atividade tipo trombina de VBL, podem aumentar a capacidade de ligação de sítios da OPN a integrinas de matriz e de superfícies de células, sugerimos que durante a patogênese da regeneração muscular post- VBL a OPN estaria criticamente envolvida no processo inflamatório agudo, e como tal atuaria primordialmente como citocina ativadora de células satélites quiescentes, seguida por atividade quimiotática e adesiva, favorecendo migração, proliferação de mioblastos e a diferenciação de miotubos. Segundo a literatura a OPN é profibrótica em certas doenças. Sugerimos que a fibrose intersticial observada, mais a presença tardia de macrófagos no local, mais a expressão citoplasmática da miogenina podem ter sido fatores relevantes que levaram ao atraso da regeneração das fibras musculares, como constatado pelo tamanho menor diâmetro das fibras. Sugere-se para a OPN um papel dual, isto é, tanto próregenerativo, como anti-regenerativo na patogênese das alterações causadas pelo veneno de B. lanceolatus
Abstract: Accident caused by venomous snakes can lead to local changes of serious and rapid development. Bothrops lanceolatus venom (BLV) contains, among other toxins, hemorrhagic metalloproteinases and non-hemorrhagic (SVMPI and SVMPIII) and prothrombin activity. As result, the venom causes hemostatic and inflammatory (via lipoxygenase and cyclooxygenase) and degenerative alterations. In this study, Bothrops lanceolatus venom (100 ?g/100?l) was injected into the gastrocnemius of rats to investigate the pathogenesis of myonecrosis (one, three, six, 18 hours and two days) and regeneration (three, seven, 14 and 21 days) by quantitative histological analysis (measurement of the small diameter one hour and 21 days post-BLV injection) and immunohistochemistry for osteopontin (OPN) protein, an inflammatory and chemotactic cytokines, with integrin binding sites to matrix proteins and cells. The number of macrophages CD68+ (resident macrophages), and CD163 (migrants macrophages), the expression of myoD and myogenin, members of the myogenic, both transcription factors family were correlated (n = 6/period). Control groups were injected with PBS (100?l). The envenomation produced local hemorrhage (initially massive), acute interstitial edema and myofibers, neutrophil and macrophage infiltration, and disruption of the perimysium sheath of connective tissue. These changes were observed up to 48 hours. The number of myonecrotic fibers was in moderate number. At 3 days, there were foci of collagen (type I) deposition surrounding groups of myoblasts. The number of macrophages (CD68 +) peaked at 24 hours, and remained significantly higher for seven days: there was no expression of CD163 macrophages. The OPN expression showed two steps, a significant increase in, from six hours to three days and seven to 14 days, and it was expressed in muscle fibers, macrophages, myoblasts, myotubes and fibroblasts. There was no MyoD imunolabeling. The myogenin expression, which is known to be typically nuclear, was also observed in the cytoplasm of myoblasts and myotubes until 7 days (peak). At 14 days, the myogenin expression became nuclear. The cytoplasmic retention of myogenin has been interpreted as a mechanism to delay myotube differentiation, since the presence in the nucleus is required for its transcriptional regulatory role. At 21 days, the regenerated fibers with central nucleus had not reached the size of intact fibers (VBL), nor that of controls. Whereas SVMPs and an enzyme with thrombin-like activity are known to increase the capacity of OPN binding to integrin of matrix and cell surfaces, we suggest that, during the pathogenesis of muscle regeneration post-VBL injection, OPN would be critically involved in an acute inflammatory process. OPN would act primarily as a cytokine activator of quiescent satellite cells and later play chemotactic and adhesive activities, promoting migration, proliferation of myoblasts, and formation and differentiation of myotubes. According to the literature, OPN is profibrotic in certain diseases. We suggest that the foci of interstitial fibrosis and the late presence of macrophages at the site of regeneration, as well as the cytoplasmic expression of myogenin may be relevant factors that lead to regeneration delay. It is suggested a pro-regenerative and anti-regenerative roles for OPN in the pathogenesis of alterations caused by B. lanceolatus venom
Mestrado
Farmacologia
Mestre em Farmacologia

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30

Fleming, Fiona. "La figure de l’étranger dans l’œuvre de D. H. Lawrence : la puissance créatrice et transformatrice de l’étrange." Thesis, Paris 10, 2016. http://www.theses.fr/2016PA100083/document.

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S’inspirant des théories de « dégénérescence » avancées par Nordau et Spengler à la fin du XIXe et au début du XXe siècle, Lawrence pose l’hypothèse d’un déclin physique et moral des individus et des formes sociales collectives en Europe. Il se met donc en quête, à travers le voyage et sa narration, de possibilités de « régénération » que pourraient offrir les lieux et les cultures extra-européens. Ce faisant, il analyse la confrontation entre ses personnages voyageurs européens et l’altérité culturelle qu’ils découvrent, une altérité portée à la fois par les individus étrangers et les sociétés auxquelles ils appartiennent, les lieux et les forces sacrées qui peuplent ces derniers. Lawrence postule que la régénération, ou réanimation, du sujet européen dépend de la capacité du voyageur à se laisser altérer par la puissance étrangère. Chaque œuvre examine ainsi le processus d’altération que subit le sujet européen et qui dépend de divers facteurs, tels que la relation à la patrie, la finalité poursuivie à travers le voyage, la condition sociale, l’éducation, et le genre.L’œuvre lawrencienne s’intéresse en effet majoritairement à la réanimation du sujet féminin et la plupart de ses personnages voyageurs sont des voyageuses non-accompagnées, un choix singulier pour l’époque. Pourtant, Lawrence n’envisage pas d’auto-émancipation du sujet féminin, car sa réanimation n’est possible que grâce à la rencontre érotique avec un autre masculin, porteur d’un monde étranger.Lawrence expérimente toutefois avec diverses formes de régénération, individuelle et collective, politique et spirituelle, susceptibles de contribuer au renouveau de la civilisation occidentale
Drawing on Nordau and Spengler’s theories of “degeneration” in the late nineteenth and early twentieth centuries, Lawrence posits the idea of a physical and moral decline of both individuals and collective social forms in Europe. He therefore sets out, through his personal travels and travel narratives, on a quest for the “regenerative” possibilities which he believes non-European places and cultures may have to offer.His travel writings examine the encounter between his European characters and the cultural otherness they experience abroad in the form of foreign individuals and societies, places and the sacred powers that inhabit those places. Lawrence postulates that the “regeneration” or revitalisation of the European subject is determined by the traveller’s ability to let himself or herself be altered by the power of otherness. Each of his works thus analyses the process of alteration undergone by the European subject, which is affected by various factors such as the latter’s relationship to the home country and the end sought through travel, his social status, education and gender.Lawrence’s works are primarily concerned with the revitalisation of the female subject and most of his travelling characters are in fact unaccompanied female travellers – an uncommon choice at the time. Yet Lawrence does not contemplate the possibility of the female subject’s self-emancipation since her revitalisation can only be brought about by the erotic encounter with a male other endowed with the power of otherness.Lawrence nonetheless experiments with several types of regeneration – individual and collective, political and spiritual – which may contribute to the renewal of western civilisation

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31

Negro, Samuele. "Signaling and transcriptomics at the degenerating-regenerating neuromuscular junction." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424427.

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The neuromuscular junction (NMJ) is a specialized tripartite synapse that allows the transmission of an electrical impulse travelling along the axon to the muscle. It is composed of the motor axon terminal (MAT), covered by perisynaptic Schwann cells (PSCs), and the muscle fibre (MF), which are separated by a basal lamina. The NMJ is not protected by anatomical barriers: it can be therefore exposed to traumas, to the attack of many pathogens including neurotoxins, and affected by many neuromuscular diseases such as amyotrophic lateral sclerosis and immune-mediated disorders, such as the Guillain-Barré and Miller Fisher syndromes. For these reasons and for its essential role in life and survival the NMJ has retained throughout vertebrate evolution an intrinsic ability for repair and regeneration, differently from central synapses. After nerve injury the glial cells of the NMJ, the PSCs, acquire a regenerative phenotype and release a series of factors that act on the stump of the MAT, providing several cues to promote neuronal regeneration. Following peripheral nerve injury, many changes taking place at the NMJ have been reported so far, but the inter- and intra-cellular signaling that occur during MAT degeneration and, more importantly, those governing the ensuing regeneration are not completely understood. We have recently established a model to study NMJ degeneration and regeneration in mice based on the specific action of -latrotoxin, a presynaptic neurotoxin isolated from the venom of the black widow spider, which targets specifically the presynaptic terminal causing its complete degeneration. Following intoxication and the subsequent clearing of MAT debris by PSCs, the axon stump regrows in few days in mice allowing complete NMJ recovery. This toxin represents therefore a simple and controlled method to induce an acute, localized and reversible nerve terminal degeneration not blurred by inflammation, and can help to identify molecules involved in the intra- and inter-cellular signalling governing NMJ regeneration. In the search of candidate molecules involved in triggering and sustaining nerve recovery we choose to perform a transcriptomic analysis of the mouse NMJs at different time points after injection of -latrotoxin. This approach has been very challenging: to our knowledge a transcriptomic analysis of the sole NMJ was never reported before. We succeeded in collecting a number of NMJs suitable for RNA isolation and sequencing of both coding and non–coding RNAs. Among the coding transcripts we selected a series of messenger RNAs (mRNAs) that are expressed at low level in controls, at higher levels during regeneration, and then return to basal when substantial regeneration is attained and we selected the mRNA encoding for the chemokine CXCL12. We found that CXCL12 is produced by PSCs during nerve degeneration, and that intraperitoneal injection of a neutralizing antibody for CXCL12 slows down the regeneration process. Moreover, the exposure of primary motor neurons to the recombinant chemokine stimulates neurite growth. These data suggest that CXCL12 is an important factor released by PSCs with a crucial role in the nerve terminal regeneration process. Parallely, we looked for molecules released by injured neurons that could activate SCs and stimulate nerve regeneration. We found that ATP released by intoxicated neurons activates a series of intracellullar signaling pathways in SCs including Ca2+, adenylate cyclase, ERK 1/2 and CREB, that are of fundamental importance for the recovery of nerve function. We propose ATP as an important alarm signal partecipating in the cross-talk between degenerating nerve terminals and adjacent PSCs not only in a model of degeneration by a spider toxin, but also in different forms of neurodegeneration of the presynaptic nerve terminal.
La giunzione neuromuscolare è una regione anatomica altamente specializzata in cui i segnali elettrici che corrono lungo l’assone del motoneurone sono convertiti in segnali chimici, che vengono a loro volta riconosciuti dalle cellule muscolari causandone la contrazione. E’ composta dal terminale assonico del motoneurone, dalle cellule di Schwann perisinaptiche che avvolgono quest’ultimo, dalla fibra muscolare e dalla lamina basale. La giunzione neuromuscolare non è protetta da barriere anatomiche e pertanto può essere bersaglio di differenti patogeni come virus, batteri, tossine. Inoltre la giunzione può essere affetta da diverse patologie quali la sclerosi laterale amiotrofica o la Sindrome di Guillain-Barrè di origine autoimmune. Per questi motivi e per la sua funzione fisiologica essenziale per la vita degli animali, non sorprende dunque la capacità della giunzione neuromuscolare di rigenerare e recuperare la sua funzionalità a seguito di differenti tipi di danno. Questa abilità si è mantenuta durante l’evoluzione animale, e differenzia le sinapsi del sistema nervoso periferico da quelle del centrale, che non hanno invece capacità rigenerativa. In seguito a denervazione le cellule di Schwann perisinaptiche mostrano una grande plasticità, de-differenziando ed iniziando a proliferare. Esse partecipano attivamente ai processi di rigenerazione nervosa, contribuendo al rilascio di diversi fattori in grado di agire sul terminale nervoso degenerato promuovendone la ricrescita ed il pieno recupero della sua funzionalità. Sono ancora poco conosciuti gli eventi intra- ed inter-cellulari che avvengono alla giunzione durante la degenerazione e soprattutto quelli che governano il processo rigenerativo del terminale nervoso. A tale scopo, nel nostro laboratorio è stato messo a punto un approccio sperimentale innovativo che permette di studiare la degenerazione e rigenerazione della giunzione neuromuscolare sfruttando il meccanismo d’azione di una neurotossina presinaptica animale, α-Latrotoxin, presente nel veleno dei ragni del genere Latrodectus. Questa tossina agisce selettivamente a livello della membrana presinaptica del motoneurone, inducendo un danno acuto e localizzato del terminale nervoso. Il terminale degenera rapidamente ma in breve tempo, in seguito alla rimozione dei detriti neuronali da parte delle cellule di Schwann, è in grado di ricrescere e di riacquisire una piena funzionalità. L’azione di tali neurotossine rappresenta quindi un sistema appropriato e controllato per indurre una degenerazione acuta, localizzata e reversibile del terminale nervoso, evitando il coinvolgimento di molti tipi cellulari e mediatori dell’infiammazione come accade nel corso della degenerazione indotta da cut/crush del nervo sciatico, tradizionalmente utilizzato fino ad oggi. Questo approccio può dunque aiutare a definire i meccanismi molecolari ed identificare i segnali intra- ed inter-cellulari alla base della degenerazione e rigenerazione nervosa. Con lo scopo di identificare molecole in grado di promuovere la rigenerazione del terminale nervoso, abbiamo messo a punto un protocollo che ci ha permesso di ottenere per la prima volta un’analisi trascrizionale a livello di giunzione neuromuscolare durante le diverse fasi di degenerazione e rigenerazione del terminale nervoso periferico in seguito ad intossicazione con α-latrotoxin. Abbiamo isolato e sequenziato da un numero adeguato di giunzioni RNA codificanti e non. Tra i diversi trascritti abbiamo selezionato quelli che presentavano un basso valore di espressione nel controllo, un aumento durante le fase rigenerativa per poi tornare ad un livello basale quando la rigenerazione è conclusa. Tra questi abbiamo approfondito lo studio della chemochina CXCL12, dimostrando che viene prodotta dalle cellule di Schwann terminali durante la degenerazione nervosa, e che l’iniezione intraperitoneale di un anticorpo neutralizzante comporta un ritardo nel processo rigenerativo. Inoltre abbiamo dimostrato che questa chemochina è in grado di promuovere la crescita dei neuriti di motoneuroni in coltura. Questi risultati suggeriscono come CXCL12 sia un importante fattore rilasciato dalle cellule di Schwann perisinaptiche con un ruolo cruciale nei processi rigenerativi del terminale nervoso. Parallelamente abbiamo indagato quali potessero essere i segnali di allarme rilasciati dal terminale nervoso in degenerazione in grado di attivare le cellule di Schwann e di promuovere la rigenerazione nervosa. Abbiamo dimostrato che l’ATP viene rilasciato da neuroni in seguito ad intossicazione con α-latrotoxin, ed è in grado di attivare nelle cellule di Schwann diverse vie di segnalazione intracellulari quali il calcio, l’AMP ciclico, ERK1/2, CREB, importanti per il recupero della funzionalità nervosa in seguito a danno. I dati presentati in questa tesi identificano l’ATP come importante molecola segnale nella comunicazione tra il terminale nervoso in degenerazione e le vicine cellule di Schwann perisinaptiche, ed estendono tale ruolo anche ad altre forme di degenerazione del terminale nervoso presinaptico.

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32

Ertürk, Ali. "In vivo imaging of the degenerating and regenerating nervous system." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-81821.

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Saclier, Marielle. "Functional phenotyping of macrophage subsets during skeletal muscle regeneration and in degenerative myopathies." Thesis, Paris 5, 2014. http://www.theses.fr/2014PA05T004/document.

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Le muscle squelettique a la capacité de se régénérer suite à une lésion grâce aux cellules satellites qui sont les cellules souches du muscle. Après dommage musculaire, les cellules satellites s’activent, prolifèrent, se différencient et fusionnent afin de reformer le muscle lésé. Cependant les cellules myogéniques ne sont pas les seules cellules impliquées dans la régénération musculaire. Des études précédentes réalisées au laboratoire ont montré chez la souris que les macrophages sont des cellules essentielles à la régénération musculaire. En effet, peu de temps après un dommage musculaire, les monocytes infiltrent le tissu lésé et se différencient en macrophages pro-inflammatoires Ly6Cpos (M1). Ces macrophages stimulent la prolifération des myoblastes et inhibent leur fusion. Puis les macrophages pro-inflammatoires changent de phénotype et deviennent des macrophages anti-inflammatoires Ly6Cneg (M2) qui stimulent la différenciation des myoblastes et les protègent de l’apoptose. Ainsi, en fonction de leur phénotype, les macrophages exercent des rôles trophiques séquentiels sur les myoblastes tout au long du processus de régénération musculaire. Dans la première partie de notre étude, nous montrons in vitro que les macrophages humains soutiennent les différentes étapes de la myogenèse. Les macrophages M1 sont fortement attirés par les myoblastes. De plus ils stimulent la prolifération des myoblastes et inhibent leur fusion. Les macrophages M2 attirent les myoblastes et stimulent leur différenciation permettant ainsi la formation de larges myotubes. En utilisant des anticorps bloquants spécifiques, nous avons identifié plusieurs molécules sécrétées par les macrophages régulant la myogenèse chez l’homme. Nos analyses in vivo chez l'homme confirment nos résultats obtenus in vitro. En effet, les macrophages M1 sont préférentiellement associés aux aires de régénération contenant des myoblastes non différenciés alors que les macrophages M2 sont associés aux aires de régénération contenant des myoblastes en différenciation. Dans un contexte de myopathie dégénérative, nous avons montré que les macrophages adoptent des phénotypes et des fonctions totalement différents des macrophages présents au cours de la régénération musculaire. Nous avons observé chez la souris et chez l’homme, que les macrophages exprimant des marqueurs M1 sont associés à la fibrose et qu’un traitement anti-inflammatoire réduit leur nombre dans le muscle dystrophique murin. Par isolement spécifique et cocultures ex vivo, nous avons montré qu'au cours de la régénération musculaire, les macrophages Ly6Cneg stimulent la production de collagène par les fibroblastes. A l'inverse au cours des myopathies dégénératives, ce sont les macrophages Ly6Cpos qui stimulent fortement l’établissement de la fibrose en agissant directement sur les fibroblastes. De plus, ces macrophages Ly6Cpos, qui régulent négativement les fibroblastes au cours de la régénération musculaire, stimulent la différenciation des fibroblastes et myofibroblastes dans les myopathies. De plus, ils les protègent de l'apoptose, participant ainsi à la persistance de ces cellules fibrosantes. Ainsi, nous avons confirmé chez l’homme in vitro et in vivo, le rôle de support séquentiel des macrophages au cours de la régénération musculaire. De plus, nous avons identifié différents effecteurs sécrétés par les macrophages M1 et M2 impliqués dans la régulation du processus myogénique chez l'adulte. Nous avons également montré que lors des myopathies dégénératives et au cours de la régénération musculaire, les macrophages adoptent un phénotype et des fonctions totalement différents, avec notamment un rôle profibrotique des macrophages pro-inflammatoires
Skeletal muscle has the ability to regenerate after a chemical or physical injury thanks to satellite cells, the muscle stem cells. After damage, satellite cells proliferate, differentiate and fused to reform muscle. Myogenic cells are not the only on cells involved. Previous studies in the laboratory showed that, in mice, macrophages are crucial for skeletal muscle regeneration. Soon after an injury, macrophages infiltrate damaged muscle and differentiate into Ly6Cpos pro-inflammatory (M1) macrophages. They stimulate proliferation of myoblasts and inhibit their fusion. Then, pro-inflammatory macrophages skew towards a Ly6Cneg anti-inflammatory phenotype (M2). Anti-inflammatory macrophages stimulate differentiation of myoblasts and protect them from apoptosis. Thus, depending on their phenotype, macrophages exert sequential trophic roles on myoblasts throughout muscle regeneration. Here, we showed in vitro that human macrophages also support different steps of myogenesis. M1 macrophages are strongly attracted by mpcs. Moreover, they secrete molecules, which stimulate proliferation of mpcs and inhibit their fusion. M2 macrophages attract mpcs and stimulate differentiation of mpcs in order to form large myotubes. Using specific blocking antibodies, we identified molecules involved in the regulation of myogenesis by M1 and M2 macrophages in a human in vitro system. In vivo analysis of regenerating human muscle sections confirmed our results obtained in vitro. M1 macrophages are preferentially associated with proliferating myogenic cells while M2 macrophages are associated with differentiating myogenic cells. In degenerative myopathies, we showed that macrophages are completely different from those present during skeletal muscle regeneration. We observed in mouse and human that M1 marker-expressing macrophages are associated with fibrosis while anti-inflammatory treatment reduced this population, in association with an improvement of the dystrophic muscle. Isolated Ly6Cneg macrophages exhibit a mixed M1/M2 phenotype. In ex-vivo coculture experiments, we showed that Ly6Cpos macrophages strongly favor establishment of fibrosis by directly acting on fibroblasts while in regenerating muscle, these Ly6Cpos macrophages negatively regulate fibrosis. To resume, we confirm in human the supportive sequential roles of macrophages during skeletal muscle regeneration in vitro and in vivo. Moreover, we identified effectors secreted by M1 and M2 macrophages involved in the regulation of the myogenic process. We also highlight that during muscle regeneration and in degenerative myopathies, macrophages exhibit different phenotype associated with opposite functions, with a pro-fibrotic role for pro-inflammatory macrophages

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Neto, Guilherme Lins de Vasconcelos Chaves. ""Estudo experimental comparativo entre auto-enxerto convencional e pré-degenerado na reconstrução de nervo"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/5/5140/tde-13092006-170317/.

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Para avaliar a eficácia do método de pré-degeneração em nervos ciáticos de ratos durante diferentes intervalos de tempo, foram realizados estudos histomorfométricos de cortes laminares obtidos ao nível do enxerto e no segmento distal do nervo receptor. Os resultados foram comparados com a técnica convencional de enxertia nervosa. Verificou-se que o tempo de pré-degeneração interfere na regeneração de novos axônios e que o período mais adequado para sua utilização situou-se ao redor de 2 semanas no modelo experimental adotado
In order to evaluate the efficacy of a predegeneration method in rat sciatic nerves during different periods of time, histomorphometric studies were performed at the graft and distal segment sites of the recipient nerves. The results were compared with the conventional nerve grafting technique. It was shown that the period of predegeneration interfered in the regeneration of new axons and the most favorable time for its use is around 2 weeks, in this experimental model

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Winterhalder, Ralph Martinelli Michele. "Muscle degenerative and regenerative changes with high altitude exposure in humans /." Bern, 1989. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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Gotlieb, Dinorah Zilbersztajn. "Estudo da expressão da miostatina em modelos murinos para doenças neuromusculares." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-14092011-140119/.

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A proteína miostatina, é um regulador negativo do crescimento muscular e a modulação de sua expressão pode consistir em tratamento para distrofias musculares. Nós estudamos expressão endógena da miostatina no músculos gastrocnêmio e diafragma de 4 modelos murinos de degeneração muscular: os camundongos Dmdmdx, SJL/J, Largemyd e Lama2dy-2J/J. Observamos que a miostatina é menos expressa no músculo gastrocnêmio do que diafragma normal, refletindo um músculo mais sujeito a lesão. Nas quatro linhagens distróficas a miostatina é menos expressa do que em camundongos normais, tanto no músculo gastrocnêmio como diafragma, sem diferença entre os dois. A analise comparativa da degeneração e regeneração muscular mostrou maior correlação da inibição da miostatina com o padrão de degeneração. Nossos resultados sugerem que o processo de degeneração, quando iniciado, e independentemente de seu grau, causa molecular primária, ou músculo afetado, parece atuar de forma similar na inibição da expressão da miostatina, possivelmente como estimulo a regeneração do dano.
Myostatin is a negative regulator of muscle growth, and its inhibition has been considered a therapeutic strategy for muscular dystrophies. We evaluated the endogenous expression of myostatin in the gastrocnemius and diaphragm muscles from 4 mouse dystrophic models including Dmdmdx, SJL/J>, Largemyd and Lama2dy2J/J. In normal mice, we observed that myostatin is less expressed in the gastrocnemius than in the diaphragm, reflecting a muscle most prone to lesions. In the 4 dystrophic models, myostatin expression was reduced, in both gastrocnemius and diaphragm muscles. The comparative analysis of the histopathology of the muscles with the expression of myostatin showed a stronger correlation with the pattern of degeneration then regeneration. Our results suggest that, when started, the process of degeneration of the muscle, independently of the primary molecular defect, or degree, seems to act in a similar pathway leading to the inhibition of the expression of myostatin in the affected muscles, possibly as a stimulus to regeneration of damage.

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Fruttiger, Marcus. "Tenascin-C expression in the degenerating and regenerating peripheral nerve : possible functional implications /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10851.

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Sihlbom, Carina. "Mass spectrometry for comparative proteomics of degenerative and regenerative processes in the brain /." Göteborg : Institute of Biomedicine, Sahlgrenska Academy, Göteborg University, 2006. http://hdl.handle.net/2077/774.

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Williams, Sarah. "The cellular and molecular changes occurring in the degenerating and regenerating olfactory system." Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272844.

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Hohaus, Christian. "Autologe Zelltransplantation bei degenerativen Bandscheibenveränderungen an der Lendenwirbelsäule." Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-109725.

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Degenerative Veränderungen der Lendenwirbelsäule beginnen bereits im Alter von unter 20 Jahren und betreffen vor allem die unteren 3 Bewegungssegmente. Die degenerativen Veränderungen an der Bandscheibe gehen mit einer Kalzifizierung der Grund- und Deckplatten der Wirbelkörper einher, was zu einer Reduktion der Nährstoffversorgung der Bandscheibe und damit zu einem Untergang der matrixbildenden Zellen und konsekutiv zu einem Flüssigkeitsverlust in der Bandscheibe führt. Als Folge nimmt die Belastung der Bandscheibe weiter ab. Die aktuellen Therapieoptionen umfassen sowohl die konservative als auch die operative Therapie, wobei allerdings nur die Folgen der Degeneration behandelt werden. Ziel einer Zelltransplantation ist es, der Bandscheibe wieder matrixbildende Zellen zur Verfügung zu stellen, damit die nutritiven Veränderungen auszugleichen und eventuell reversibel zu machen. Dieser Effekt konnte im Tierversuch nachgewiesen werden, woraufhin eine klinische Studie initiiert wurde. Im Rahmen der publizierten klinischen prospektiven, randomisierten Studie konnte gezeigt werden, dass die Transplantation autologer Chondrozyten, die bei einer notwendigen operativen Therapie eines sequestrierten Bandscheibenvorfalls gewonnen wurden, einen sowohl klinisch als auch bildmorphologisch positiven Effekt auf die degenerierten Bandscheiben hat. Es kam zu einer signifikanten Reduktion der Schmerzsymptomatik und einer Steigerung der Lebensqualität in der Gruppe der transplantierten Patienten. Die Bandscheibenhöhe zeigt sich stabil über den Beobachtungszeitraum von 2 Jahren.

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Badan, Flori-Irina. "Temporal dynamics of degenerative and regenerative events associated with cerebral ischemia in aged rats." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=972333967.

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Campos, Friz Marianella [Verfasser], and Dirk-Rösken [Akademischer Betreuer] Straatmann. "Degenerative und regenerative Reaktionen nach Läsion des Nervus ischiadicus in ICAM-1-defizienten Mäusen." Freiburg : Universität, 2011. http://d-nb.info/1115490532/34.

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Mesquita, Isanio Vasconcelos. "Estudo experimental comparativo entre enxerto de nervo convencional e enxerto de nervo preservado a frio." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/5/5140/tde-12122017-132414/.

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INTRODUÇÃO: A reparação das lesões de nervos periféricos com perda extensa de substância, onde a sutura direta não é viável, ainda apresenta nos dias atuais resultados variáveis e dependentes de diversos fatores. O tratamento mais comumente utilizado nestes casos é a auto-enxertia de nervos, com sacrifício de um nervo de outra região do corpo, procedimento que, entretanto, pode trazer algumas dificuldades e consequências. Desta forma, a busca por novas técnicas, como a possibilidade de utilização de nervos preservados em baixas temperaturas, representa um avanço inestimável no campo da reparação de lesões nervosas. OBJETIVO: O objetivo deste estudo foi realizar avaliações funcionais, eletrofisiológicas e histomorfométricas que permitam comparar a regeneração nervosa autógena em enxerto convencional versus enxerto preservado a frio, em modelo experimental de ratos, após denervação a fresco ou conservação de um segmento do nervo em baixa temperatura por 14 dias e por 50 dias. MÉTODOS: Foram utilizados 20 ratos Wistar de peso e idades aproximadamente iguais, divididos em quatro grupos de cinco animais. Os grupos 1 e 3 serviram de controle respectivamente para os grupos 2 e 4, utilizando enxertia de nervo convencional por 14 dias (grupo 1) e por 50 dias (grupo 3). O grupo 2 utilizou enxertia de nervo preservado a 4 graus Celsius em solução Celsior® por 14 dias, enquanto o grupo 4 foi submetido à preservação a frio na mesma solução por 50 dias. Foram realizadas análises funcionais da marcha, análises de potenciais evocados e análises histomorfométricas dos animais em diversos momentos. As análises funcionais utilizaram uma aparelhagem própria para estudo da marcha em pequenos animais de experimentação, denominada catWalk®, que fornece medidas estáticas e dinâmicas da marcha, com parâmetros como a pressão em relação à pata contralateral e a área máxima da impressão plantar do animal, tendo sido captados os dados antes do procedimento de retirada do enxerto e após a realização da enxertia, neste último caso com avaliações quinzenais até que tenham sido completados 60 dias de pós- operatório. As análises de potenciais evocados motores analisaram a latência e a amplitude dos estímulos nervosos e foram realizadas 60 dias após os procedimentos de enxertia. As análises microscópicas observaram a contagem de axônios mielinizados e a área destas fibras nervosas nas regiões proximal e distal aos reparos, aos 60 dias após os procedimentos, comparando também as relações entre a região distal e proximal de cada um destes parâmetros através dos índices de regeneração e mudança de área. RESULTADOS: A enxertia com nervo preservado a frio por 14 dias apresentou resultado funcional semelhante ao seu grupo controle na análise da área máxima de contato e da pressão máxima de contato da pata operada em todas as avaliações. Já a conservação do enxerto a frio por 50 dias resultou em superioridade funcional em todos as avaliações em relação a seu grupo controle. Os estudos eletrofisiológicos mostraram cada grupo de enxertia preservada a frio com resultados similares a seu grupo controle, tanto em relação à latência, quanto à amplitude nos dois músculos avaliados. As análises histomorfométricas resultaram em índices de regeneração e de mudança de área semelhantes na comparação entre os grupos 60 dias após os procedimentos de enxertia. CONCLUSÕES: A conservação a frio do enxerto de nervo durante 14 dias e durante 50 dias apresentou resultados funcionais da regeneração iguais ou superiores aos enxertos convencionais e resultados eletrofisiológicos e histológicos semelhantes aos respectivos grupos controle de enxertos convencionais, demonstrando um futuro promissor para a utilização clínica de enxertos preservados a frio em um \"banco de nervos\"
INTRODUCTION: The repair of peripheral nerve injuries with extensive loss of substance, where direct suture is not feasible, at the present time still has variable results and dependence on many factors. The treatment most commonly used in these cases is the nerve autograft, with sacrifice of a nerve from another region of the body. This procedure, however, can sometimes lead to some difficulties and consequences. Therefore, the search for new techniques such as the possibility of using cold preserved nerves, is a great advancement in the field of repairing nerve damage. OBJECTIVE: The purpose of this study was to perform functional, electrophysiological and histomorphometric evaluations to compare conventional autografts versus cold-preserved autografts of the sciatic nerves of rats, after fresh denervation or conservation of a nerve segment at low temperature for 14 days and 50 days. METHODS: 20 Wistar rats of approximately equal ages and weight were divided into 4 groups of 5 animals. Groups 1 and 3 were treated with a conventional nerve graft after denervation for 14 days and 50 days, respectively; they served as controls for groups 2 and 4, which were treated with cold-preserved nerve grafts immersed in a Celsior® solution at 4 degrees Celsius for 14 and 50 days, respectively. Functional gait analysis, evoked potential analysis and histomorphometric analysis of the animals were performed at different times. Functional analysis used equipment for gait study in small animal experiments, called catWalk®, which provides static and dynamic measurements, with parameters such as pressure relative to contralateral paw and the maximum area of the footprint of the animal, and these data were captured before the graft withdrawal procedure and after grafting, in this latter case the functional analysis was made every 15 days until they had been completed 60 days after surgery. The motor evoked potential analysis examined the latency and amplitude of nerve stimuli and was made 60 days after the grafting procedures. The microscopic analysis measured myelinated axons and the area of these nerve fibers in the proximal and distal regions to the repair sites at the end of 60 days after the procedures, also comparing the relationship between the distal and proximal regions of each of these parameters through the regeneration and area change rates. RESULTS: Cold preservation of nerve graft for 14 days showed functional results similar to those of its control group for the maximum contact area and for the maximum pressure intensity of the operated paw in all evaluations. Cold preservation of nerve graft for 50 days resulted in functional superiority in all assessments compared with its control group. Cold preservation of nerve graft for 14 days and 50 days showed electrophysiological results similar to those of their respective control groups, both in terms of latency, as to the amplitude in the two muscles evaluated. Histomorphometric analysis showed similar regeneration and area change rates for all the groups 60 days after the grafting procedures. CONCLUSIONS: The cold preservation of nerve grafts for 14 days and 50 days showed similar or superior functional results and similar electrophysiological and histological results compared with their respective conventional graft control groups, indicating a promising future for the clinical utilization of cold preserved grafts in a \"nerve bank\"

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Carpenedo, Richard L. "Microsphere-mediated control of embryoid body microenvironments." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33948.

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Embryonic stem cells (ESCs) hold great promise for treatment of degenerative disorders such as Parkinson's and Alzheimer's disease, diabetes, and cardiovascular disease. The ability of ESCs to differentiate to all somatic cell types suggests that they may serve as a robust cell source for production of differentiated cells for regenerative medicine and other cell-based therapeutics. In order for ESCs to be used effectively in clinical settings, efficient and reproducible differentiation to targeted cell types must be demonstrated. The overall objective of this project was to engineer microenvironmental control over differentiating ESCs through the formation of embryoid bodies (EBs) uniform in size and shape, and through the incorporation of morphogen-containing polymer microspheres within the interior of EBs. The central hypothesis was that morphogen delivery through incorporated polymer microspheres within a uniform population of EBs will induce controlled and uniform differentiation of ESCs. Rotary suspension culture was developed in order to efficiently produce uniform EBs in high yield. Compared to static suspension culture, rotary suspension significantly improved the production of differentiating cells and EBs over the course of 7 days, while simultaneously improving the homogeneity of EB size and shape compared to both hanging drop and static EBs. The diffusive transport properties of EBs formed via rotary suspension were investigated using a fluorescent, cell permeable dye to model the movement of small morphogenic molecules within EBs. Confocal microscopy, cryosections and EB dissociation all demonstrated that the dye was not able to fully penetrate EB, and that the larger EBs at later time points (7 days) retarded dye movement to a greater extent than earlier EBs (days 2 and 4). Polymer microspheres capable of encapsulating morphogenic factors were incorporated into EBs in order to overcome the diffusional limitations of traditional soluble delivery. The size of microspheres, microsphere coating, microsphere to cell ratio, and rotary mixing speed were all observed to influence incorporation within EBs. The use of microsphere-mediated delivery within EBs to direct cell differentiation was examined. Microsphere-mediated delivery of retinoic acid (RA) induced formation of uniquely cystic spheroids with a visceral endoderm layer enveloping a pseudo-stratified columnar epithelium, and with spatial localization of transcriptional profiles similar to the early primitive streak stage of mouse development. Continued differentiation of RA MS EBs in defined media conditions was assessed. Gene expression demonstrated that regular serum enhanced endoderm induction, serum-free media supported ectoderm differentiation, while mesoderm was most prominent in untreated EBs in full serum. In summary, this work has realized a unique approach for stem cell differentiation through modification of the internal microenvironment of ESC spheroids. This novel inside-out method toward engineering EBs demonstrated that the mode of morphogen delivery significantly affected the course of differentiation. These studies provide the basis for ongoing work, which will utilize the choice of microsphere material, coating, and morphogen in order to uniquely study mechanisms of ESC differentiation and achieve unparalleled engineering of the EB microenvironment.

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Yu, Diana Xuan. "Towards functional regeneration of the central nervous system glial calcium signaling in reactive gliosis and the therapeutic potential of bone marrow-derived mesenchymal stem cells for retinal degenerative diseases /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3320122.

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Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed Sept. 11, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 147-180).

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CANZI, LAURA. "Human stem cells for the treatment of motorneuron diseases: regenerative potential, translatability and development of new biotechnologies. Cellule staminali umane per la cura delle malattie degenerative del motoneurone." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2010. http://hdl.handle.net/10281/19217.

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Stem cell therapy is considered one of the most promising approaches against different neurodegenerative disorders, including Amyotorophic Lateral Sclerosis (ALS). The evidence that the systemic injection of human cord blood mononuclear cells (HuCB-MNC) was able to reduce the clinical outcomes and increase the lifespan in a murine model of fALS1, the SOD1G93A mouse, even if localized far from affected motor neurons, opens the way for new possible candidates and alternative ways of administration. Here the effect of human skeletal muscle-derived stem cell (SkmSCs) was investigated by single administration in lateral ventricles in the most characterized model of spontaneous motor neuron degeneration, the Wobbler (Wr) mouse. Before evaluating clinical progression, we found that SkmSCs (previously labeled with the super paramagnetic contrast agent Endorem™ and/or with the fluorescent nuclear dye Hoeschst 33258): 1) spread along the whole ventricular system as far as the ependymal canal at the spinal cord level; 2) remained for a longer time in the Wr than in the healthy mice, and; 3) did not significantly migrate to the parenchyma. Similar to the SOD1G93A mice treated with HuCB-MNCs, the transplantation of SkmSCs: 1) significantly improved the disease progression of ALS-related Wr motorneuropathology; 2) this effect was not associated with a migration of SkmSCs close to the degenerating motor neurons. Very interestingly, we also found that cell grafting in the Wr brain ventricles significantly increased the gene expression of anti-inflammatory cytokines or chemokines activated in the inflammatory response. These results further confirm the consistency of the hypothesis of the bystander effect of stem cells in motor neurodegenerative disorders by a mechanism of action aimed at reducing the neuroinflammatory response.

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Pistarini, Luciana Crepaldi Yazawa. "Avaliação in vivo do potencial regenerativo na Degeneração Walleriana de nervos periféricos - com a utilização de laser de baixa potência e composto polivitamínico 3-NERVE®." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-24082015-083013/.

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Nas áreas médica e odontológica existem situações clínicas e cirúrgicas que podem ter, como consequência, um dano ao tecido conjuntivo nervoso, chamado de neuropatia. O objetivo deste trabalho é avaliar terapias para tratamento das neuropatias causadas por manipulação do feixe nervoso periférico, minimizando ou eliminando sintomas causados pela lesão. O estudo foi feito em 60 ratos machos Wistar, com a avaliação morfológica da degeneração Walleriana e da regeneração do tecido nervoso no 15º e 30º dia após o trauma. A lesão consistiu na exposição e compressão do nervo isquiático da pata direita do animal, através de três nós consecutivos com fio de sutura e distância entre eles de ~ 2mm. Três tratamentos sobre a lesão foram comparados: o uso do biomaterial 3-NERVE®, a laserterapia de baixa potência e a associação dos dois. Os resultados histológicos revelaram que o biomaterial aumentou o processo inflamatório, mas modulou a degeneração inicial, através do surgimento de células de neoformação, favorecendo a regeneração nervosa no decorrer dos trinta dias. A laserterapia foi um tratamento favorável para a parestesia porque modulou os danos do processo de degeneração inicial e estimulou o reparo do tecido desde os 15 primeiros dias. Ao atingir os 30 dias o tecido se apresentou organizado e com uma quantidade menor de tecido neoformado quando comparado com o uso do biomaterial. A associação das terapias associou as propriedades das duas terapias, pois modulou a inflamação inicial, propiciou o aumento do número de células de neoformação do tecido nervoso e favoreceu a regeneração dos feixes nervosos nas amostras de 15 e 30 dias. Conclui-se que o não tratamento dificulta ou impede a regeneração nervosa, pois qualquer uma das terapias citadas modula os eventos desencadeados pela lesão. A associação do uso da laserterapia com o 3-NERVE® mostrou melhores resultados.
In medical and dental areas are clinical and surgical situations that may have, as a result, damage to the nervous tissue. This is called a neuropathy. The objective is to support therapies for treatment of neuropathies caused by manipulation of the peripheral nervous bundle, minimizing or eliminating symptoms caused by injury. The study was conducted in 60 male Wistar rats by morphological analysis of Wallerian degeneration and regeneration of nerve tissue in the 15th and 30th day after the trauma. The lesion consisted of exposure and sciatic nerve compression of the right paw of the animal through three consecutive nodes with suture and the distance between them of ~ 2mm. Three treatments on the injury were compared: the use of -NERVE® biomaterial, the low level laser therapy and their association. Histological findings revealed in samples 15 and 30 days the biomaterial increased inflammation and degeneration of the initial modulated through the cell neogenesis emergence favored nerve regeneration in the course of 30 days. Laser therapy was a favorable treatment for paresthesia because modulates the damage of the initial degeneration process and stimulates tissue repair since the first 15 days. When reaching the 30 days the tissue was organized and presented with a smaller amount of neoformed tissue when compared with the use of the biomaterial. The combination therapies of the modulated the initial inflammation, led to an increase in the number of cells neogenesis and promoted nerve tissue regeneration of nerve bundles in the samples 15 and 30 days. We conclude that no treatment hinders or prevents nerve regeneration, for any of the therapies mentioned modulate the events triggered by the injury. The association between the use of laser therapy with Nerve® proved with better results.

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García-García, Diana. "Müller Cells and Retinal Regeneration : The Role of the Hippo/YAP Signaling Pathway Yap Haploinsufficiency Leads to Müller Cell Dysfunction and Late-Onset Cone Dystrophy Linking YAP to Müller Glia Quiescence Exit in the Degenerative Retina." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL068.

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Les maladies dégénératives de la rétine sont une des causes principales de cécité. Parmi les différentes stratégies thérapeutiques actuellement étudiées, notre équipe s’intéresse au potentiel régénératif de la rétine. Une source cellulaire d'intérêt sont les cellules de Müller, principal type de cellules gliales de la rétine capables de se réactiver en cas de dégénérescence, un processus appelé gliose réactive, et dans certaines espèces d’adopter des caractéristiques de cellules souches. Si un tel processus confère la capacité de régénérer la rétine chez les téléostéens, il est cependant largement inefficace chez les mammifères. Avoir une meilleure connaissance des mécanismes moléculaires sous-jacents pourrait aider à transformer leur potentiel de régénération en nouvelles stratégies thérapeutiques en condition pathologique de dégénérescence rétinienne. Dans ce contexte, mon laboratoire s'est focalisé sur l'effecteur terminal de la voie Hippo, le cofacteur de transcription YAP, dont il a été démontré qu'il stimule la régénération de plusieurs organes en cas de lésion. Dans la rétine, YAP est spécifiquement exprimé dans les cellules de Müller et son niveau d’expression augmente en cas de lésion. Cependant, sa fonction dans l'homéostasie rétinienne, et en particulier son rôle dans la régénération rétinienne, sont encore inconnus. La première partie de ma thèse visait donc à décrypter la fonction de YAP dans les cellules de Müller de souris dans des conditions physiologiques et pathologiques. Nous avons révélé que YAP joue un rôle central dans l'homéostasie des cellules de Müller et en tant que tel, est un acteur clé de la survie des cônes au cours du vieillissement. En cas de lésion rétinienne, nous avons montré que YAP est essentiel pour la réactivation des gènes du cycle cellulaire qui accompagne normalement la gliose réactive. Dans ce contexte, nous avons également trouvé une interaction fonctionnelle entre YAP et la voie de signalisation EGFR, suggérant une fonction de YAP en tant qu’intégrateur des réseaux de signalisation mis en jeu dans le contexte régénératif. J'ai également constaté que la suractivation de YAP est suffisante pour induire la reprogrammation des cellules de Müller de souris en cellules hautement prolifératives […]. Dans l'ensemble, ce travail met en évidence le rôle critique de YAP dans la sortie de quiescence des cellules de Müller chez les mammifères et révèle ainsi une cible potentielle pour la médecine régénérative. La deuxième partie de mon projet de doctorat naît des découvertes émergentes mettant en évidence les voies inflammatoires comme régulateurs du processus de régénération. […] De plus, des découvertes récentes sur le rôle de YAP dans la régulation du processus inflammatoire m’ont conduit à faire l'hypothèse qu'il pourrait jouer un rôle dans la relation entre l'inflammation et la régénération rétinienne. J'ai donc cherché à étudier le rôle joué par l'inflammation sur le comportement des cellules de Müller de souris, et à comprendre comment YAP s'inscrit dans cette interaction. J'ai découvert de manière inattendue qu'un contexte pro-inflammatoire établi par les cellules microgliales stimule la prolifération des cellules de Müller de souris dans des explants rétiniens. De plus, mes résultats ont montré que cet effet mitogène se produit de manière dépendante de YAP. Par ailleurs, j'ai découvert que l'effet de la surexpression de YAP sur la prolifération des cellules de Müller peut être potentialisé par un environnement pro-inflammatoire et aboli en cas d’ablation des microglies. Enfin, nous avons constaté que, à son tour, YAP régule des cytokines inflammatoires clés. Dans l'ensemble, cette partie de mon projet permet non seulement d’approfondir nos connaissances concernant l'impact de l'inflammation sur le comportement des cellules de Müller de la souris, mais met également en évidence YAP en tant qu'acteur clé dans la connexion entre l'inflammation et la régénération rétinienne
Degenerative diseases of the retina are one of the main causes of blindness. Among the various therapeutic strategies currently being studied, our team is focusing on the regenerative potential of the retina. One cellular source of interest are Müller cells, the main type of glial cells in the retina capable of reactivating in case of degeneration, a process called reactive gliosis, and in some species adopting certain characteristics of stem cells. If such a process sustains powerful regeneration abilities in teleosts, it is however largely inefficient in mammals. Hence, increasing our knowledge of the molecular mechanisms underlying the behaviour of these cells under pathological conditions may help turning their regenerative properties into new therapeutic strategies. In this context, my laboratory focused on the terminal effector of the Hippo pathway, the co-transcriptional factor YAP, which has been shown to stimulate regeneration of several injured organs. In the retina, YAP is specifically expressed in Müller cells and upregulated in case of damage. However, its function in retinal homeostasis, and its role in retinal regeneration remained unknown.The first part of my PhD aimed at deciphering YAP function in mouse Müller cells in both physiological and pathological conditions. In essence, we revealed a central role of YAP in Müller cell-dependent retinal homeostasis and as such, as a key player for cone survival during aging. In case of retinal damage, we showed that YAP upregulation is critical for cell-cycle gene reactivation that normally accompanies reactive gliosis. In this context, we also found a functional interaction between YAP and the EGFR signaling pathway, supporting a function of YAP as a hub within the complex signaling network of key regenerative signaling pathways. I also found that YAP overactivation is sufficient to induce mouse Müller cell reprogramming into highly proliferative cells, mimicking a fish or amphibian condition, when Müller cells spontaneously proliferate upon injury. As a whole, this work highlights the critical role of YAP in driving mammalian Müller cells to exit quiescence and thus reveals a potential target for regenerative medicine.The second part of my PhD project stemmed from the emerging discoveries highlighting inflammatory pathways as regulators of the regenerative process. Although inflammation is considered to hamper retinal regeneration in mammals, there are no studies regarding the influence of inflammation on mouse Müller cell-dependent regenerative process. In addition, recent discoveries on the role of YAP in the regulation of the inflammatory process lead to the hypothesis that it could play a role in the relationship between inflammation and retinal regeneration. I thus aimed at investigating the role played by the injury-induced inflammation on mouse Müller cell behavior and how YAP fits in this interplay. I unexpectedly discovered that a microglial-dependent pro-inflammatory context stimulates mouse Müller cell proliferation in retinal explants. Importantly, my results showed that this mitogenic effect occurs in a YAP-dependent manner. Moreover, I uncovered that the effect of YAP overexpression on Müller cell proliferation can be potentiated by a pro-inflammatory environment, and abolished upon microglia depletion. Finally, we found that, in turn, YAP regulates key inflammatory cytokines. Altogether, this part of my project not only deepen our knowledge regarding the impact of inflammation on mouse Müller cell behavior, it also highlights YAP as a key player in the crosstalk between inflammation and retinal regeneration

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Lok, Peter Yin Cheung. "Development of a novel minimally invasive scaffold system for spinal disc repair." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12583.

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Debilitating chronic back pain caused by severe spinal disc degeneration leads to loss of mobility, affecting quality of life, a significant loss of productivity for the employee and the employer. Currently available surgical intervention options, such as spinal fusion and total disc replacement, seeking only to alleviate pain, are not only invasive, but fail to address the underlying biological causes of spinal disc degeneration, or restore normal physiological spinal motion. Recently proposed tissue engineering approaches focus on stopping and reversing the degenerative cascade, which has a promising regenerative effect, though not without significant challenges before a clinical application is made available, including tumourigenesis risks and proof of efficacy. A minimally invasive nucleus pulposus replacement option, which preserves the competent annulus fibrosis, while replacing the removed degenerated nucleus tissue with a prosthesis, provides an alternative for early disc degeneration, though most commercially available types are at clinical trial stages. There is an opportunity for developing a minimally invasive nucleus pulposus replacement type spinal implant system that restores disc biomechanics and addresses biological degenerative causes. This body of work details the design, development, fabrication, prototyping, verification and validation of this novel implant system. The implant system consisted of a configuration of scaffold and hydrogel interpenetrating polymer network composite delivered minimally invasively via a cannula system, after the nucleus pulposus is removed in a nucleotomy with a set of specialised tools. Implantation of the novel prosthesis was shown to be successful in various spinal disc models, in meeting identified design and functional requirements, including biomechanical loading, resistance to expulsion and radiopacity.

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Chiang, Hao Yu, and 江皓郁. "Degeneration and Regeneration of Cutaneous Nerves in Mice." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/50978690214935931509.

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碩士
國立臺灣大學
解剖學研究所
85
The documentation of epidermal nerves("free nerve endings") have had a long and controversial history. By applying immunohistochemistry, these fibers can be demonstrated by various axonal markers, including protein gene product 9.5 (PGP).This sensitive marker can label all the nerves, in particular, unmyelinated ones. We have showed the axonal nature of PGP-immunoreactive profiles by sciatic nerve transection in rats, and found a series changes in the epidermis, including changes in the phenotype of Langerhans cells and in the thickness of epidermis.These results raised several issues: (1)How the degeneration of epidermal nerves is related to Wallerian degeneration?(2)Whether the changes after denervation are species-specific or not? Thus, we tried to set up an experimental system to study the pattern of cutaneous denervation. To address the above issues, we extended our observation to mice by transecting the sciatic nerve on one side with the other side as control. The footpads in the hindpaws were analyzed immunohistochemically and ultrastructurally at various time points. The ultrastructural results showed that dermal nerves began to degenerate within 24 hrs and were still recognizable on the 2nd day while epidermal nerves disappeared at the same time. The results suggested that, degeneration of the terminal part ( epidermal nerves)occurred earlier than that of their parent axons(dermal nerves). No changes in PGP- immunoreactivity was observed in Langerhans cells after denervation in mice. Reinnervating axons appeared at the epidermis-dermis junction on one side of the pad within 14 days, and these axons appeared to sprout from the neighboring saphenous nerve. We applied the same approach on the hairy skins in the hindpaws to define the spatial patterns of cutaneous innervation, and demonstrated the innervation territories of sciatic and saphenous nerves. These results are useful as a fundation to study sensory neuropathy in the human and various mutant mice with defects in sensory innervation.

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Dissertations / Theses on the topic 'Degeneration and regeneration'

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