Academic literature on the topic 'Tunique intime'

Objective: To study topographical variations of the healthy human long saphenous vein structure and its age-related changes. Methods: One hundred and forty-four specimens taken at different levels from 36 long saphenous veins were studied by correlated light microscopy and scanning electron microscopy. Results: Continuous remodelling occurs in the wall of the long saphenous vein during the progress of life. In young subjects, the intima was narrow, circular muscular cells were present only in the media, and a rich elastic framework was evident in all the three tunicae. A progressive increase in collagen content and longitudinal musculature accompanied by a reduction in elastic tissue was observed in relation to ageing. Furthermore, at all ages, the saphenous vein wall thickened in its caudal portion due to a greater cellular proliferation and deposit of extracellular matrix. Conclusions: The topographical variations in saphenous wall structure as well as its age-related remodelling likely represent the parietal reaction to the physiological hydrostatic load related to the vertical pasture.

Background: In the last decades, Tunisia has undergone major demographic, socio-economic and lifestyle (including diet) changes, with drastic increases in excess adiposity and nutrition related non-communicable diseases (NCDs). This review provides an update of the nutritional situation in Tunisia. Methods: Several Tunisian datasets or international databases were used to assess availability and consumption of foods and health outcomes. Results: Both from national aggregated availability data and individual food consumption data, there was a trend both of increasing food intake and modernization/westernization of the diet (especially in urban areas), towards more consumption of dairy and meat products, sugar, fat and salt. But consumption of fruits and vegetables was still above WHO recommendations. Except for iodine, micronutrients deficiency (iron, vitamin A and D) was markedly, but unevenly, present among specific groups (e.g., a third of adult women had anemia). Among infants, both exclusive and predominant breastfeeding were low, while the minimum diet diversification rate was 63%. Among children, stunting was residual but increase of overweight was a concern. In 2016 17.6% of men and 34.6 % of women over 15 y. were obese and 15.5% had diabetes, a twofold increase in the last decades. These prevalence were much higher in urban and more developed areas. Also, 86% of the mortality rate was attributable to NCDs. Conclusion: Addressing the double burden of malnutrition and NCDs is a priority and should be based on a sustainability framework, involve a diversity of stakeholders and emphasize double duty actions and reduction of nutrition and health inequalities. Keywords: Tunisia, diet, food insecurity, micronutrient deficiencies, nutritional status, obesity, non-communicable diseases.

Various in vitro methods have been used for biological and synthetic scaffold fabrication. Some use polymers such as expanded polytetrafluoroethylene (ePTFE), polytetrafluoroethylene (PTFE), and polyethylene terephthalate (PET), while others use allogeneic or xenogeneic biological materials (e.g. blood vessels). While fabricating a biological scaffold, the first step is complete decellularization by enzymes (e.g. trypsin, collagenase, etc.) or chemicals (e.g. SDS, Triton-X, etc.), and the scaffolds should maintain its extracellular matrix (ECM). The second step involves re-endothelization so as to get fully biomimetic graft. In this study, we focused (concentrated) on the fabrication of a human saphenous vein scaffold by using various chemicals. We observed that cationic 1% SDS solution (Group B) performed excellent decellularization without altering the extracellular matrix as compared to the other chemicals like 0.25% trypsin and 70% ethanol (Groups C and D). Decellularization percentage and intactness of ECM (in all tunicae – intima, media, and adventitia) were confirmed based on histology. The PicoGreen assay showed that Group B (1% SDS decellularized scaffold, n = 3) had no detectable residual DNA. Re-endothelization on the complete decellularized scaffold (Group B) was done in both ways, without initial fibrin glue application (Group E) and with prior fibrin glue application (Group F). The vWF and lectin expressions suggested that endothelial cells did not alter their phenotype on human saphenous vein scaffolds. Uniaxial tensile testing revealed no significant differences in strain characteristics and modulus between native tissue and decellularized scaffolds. The live-dead (FDA/PI) and MTT assays confirmed the endothelial cell proliferation and viability, and the scanning electron microscope (SEM) data showed that the cells adhered to the scaffold matrix (Group F). We concluded that an allogeneic human saphenous vein scaffold with desirable properties can be fabricated and re-endothelialized to form a non-thrombogenic intimal surface in vitro using this protocol.

Le remodelage artériel, définit comme une modification de taille de l'artère, et l'activation de la coagulation dépendant du Facteur Tissulaire (FT) sont deux déterminants importants des manifestations ischémiques au cours de la pathologie athéroscléreuse et après angioplastie artérielle. Le remodelage artériel sous la forme d'un élargissement compensateur à la phase précoce de l'athérosclérose est un processus adaptatif retardant la constitution d'une sténose hémodynamiquement significative. Cet élargissement s'accompagne de phénomènes inflammatoires pariétaux favorisant la rupture de plaque, et l'exposition au sang circulant du FT très thombogène. L'angioplastie entraîne une rupture de plaque athéroscléreuse qui expose également le FT au sang circulant. Après angioplastie, le remodelage artériel est le principal déterminant de la resténose. La rupture spontanée de plaque athéroscléreuse ou induite par l'angioplastie entraîne une activation des monocytes circulants se traduisant en particulier par une augmentation d'expression du FT monocytaire. Après induction d'une athérosclérose, l'angioplastie iliaque chez le lapin hypercholestérolémique entraîne le développement d'une hyperplasie intimale et d'un remodelage artériel sous forme d'élargissement compensateur adapté ou insuffisant. La modulation de la voie de l'oxyde nitrique (NO) par apport de L-arginine ou par inhibition des NO synthétases n'a pas eu d'effet bénéfique sur le remodelage artériel et la resténose post-angioplastie. De plus la fonction endothéliale n'était pas améliorée in vitro par la L-arginine. L'inhibition du système rénine-angiotensine par un inhibiteur de l'enzyme de conversion de l'angiotensine, le périndopril, a permis de réduire l'hyperplasie intimale, avec un effet favorable sur le remodelage artériel et la resténose. Le périndopril n'a pas eu d'effet sur la réendothélialisation après angioplastie. L'étude du FT dans le même modèle montre que l'angioplastie augmente l'expression du FT par les monocytes circulants. La L-arginine s'est opposée à l'augmentation d'expression du FT monocytaire après angioplastie ce qui pourrait avoir un effet bénéfique sur l'activation de la coagulation induite par la rupture de plaque. Le périndopril a augmenté l'expression du FT par les monocytes, peut-être par une amélioration de la fonctionnalité des monocytes, ou par une diminution de pénétration des monocytes activés dans la paroi artérielle. L'angioplastie a également augmenté l'expression du FT dans la paroi artérielle iliaque et aortique, mais de façon beaucoup plus importante en cas de régime à 2 % de cholestérol par rapport à un régime à 0,2% de cholestérol, suggérant un effet bénéfique des régimes hypolipémiant au cours de l'athérosclérose passant par une diminution du FT pariétal. Par contre l'expression du FT par les monocytes s'est avérée moins importante sous régime à 2% de cholestérol que sous 0,2%, en faveur d'un effet délétère du régime à 2% sur la fonctionnalité monocytaire. Enfin, l'expression du FT par les monocytes circulants est augmentée en cas de remodelage artériel défavorable et de resténose après angioplastie dans ce modèle suggérant un lien entre FT et remodelage en l'absence de modulation pharmacologique indirecte de la voie du FT. Le FT pourrait ainsi constituer un lien entre inflammation pariétale, thrombose locale, et remodelage vasculaire.