Littérature scientifique sur le sujet « Vascular calcification (VC) »

Vascular calcification (VC) is regarded as a common feature of vascular aging. Klotho deficiency reportedly contributes to VC, which can be ameliorated by restoration of Klotho expression. However, the specific mechanisms involved remain unclear. Here, we investigated the role of autophagy in the process of Klotho-inhibiting VC. The clinical study results indicated that, based on Agatston score, serum Klotho level was negatively associated with aortic calcification. Then, Klotho-deficient mice exhibited aortic VC, which could be alleviated with the supplementation of Klotho protein. Moreover, autophagy increased in the aorta of Klotho-deficient mice and protected against VC. Finally, we found that Klotho ameliorated calcification by promoting autophagy both in the aorta of Klotho-deficient mice and in mouse vascular smooth muscle cells (MOVAS) under calcifying conditions. These findings indicate that Klotho deficiency induces increased autophagy to protect against VC and that Klotho expression further enhances autophagy to ameliorate calcification. This study is beneficial to exploring the underlying mechanisms of Klotho regulating VC, which has important guiding significance for future clinical studies in the treatment of VC.

VC (vascular calcification) is highly prevalent in patients with CKD (chronic kidney disease), but its mechanism is multifactorial and incompletely understood. In addition to increased traditional risk factors, CKD patients also have a number of non-traditional cardiovascular risk factors, which may play a prominent role in the pathogenesis of arterial calcification, such as duration of dialysis and disorders of mineral metabolism. The transformation of vascular smooth muscle cells into chondrocytes or osteoblast-like cells seems to be a key element in VC pathogenesis, in the context of passive calcium and phosphate deposition due to abnormal bone metabolism and impaired renal excretion. The process may be favoured by the low levels of circulating and locally produced VC inhibitors. VC determines increased arterial stiffness, left ventricular hypertrophy, a decrease in coronary artery perfusion, myocardial ischaemia and increased cardiovascular morbidity and mortality. Although current therapeutic strategies focus on the correction of phosphate, calcium, parathyroid hormone or vitamin D, a better understanding of the mechanisms of abnormal tissue calcification may lead to development of new therapeutic agents, which could reduce VC and improve cardiovascular outcome in CKD patients. The present review summarizes the following aspects: (i) the pathophysiological mechanism responsible for VC and its promoters and inhibitors, (ii) the methods for detection of VC in patients with CKD, including evaluation of arterial stiffness, and (iii) the management of VC in CKD patients.

Vascular calcification (VC) is being recognized as a common complication at all stages of chronic kidney disease, particularly in patients on dialysis. Traditional and nontraditional cardiovascular risk factors both appear to be involved in the development of VC in this population. Although few studies focusing exclusively on peritoneal dialysis (PD) patients are available, some data support the view that VC constitutes an independent prognostic marker of morbidity and mortality in the PD population. In this review, we discuss the potential pathophysiologic pathways of VC in PD patients, and we examine the relevant clinical data.

Vascular calcification (VC), which is categorized by intimal and medial calcification, depending on the site(s) involved within the vessel, is closely related to cardiovascular disease. Specifically, medial calcification is prevalent in certain medical situations, including chronic kidney disease and diabetes. The past few decades have seen extensive research into VC, revealing that the mechanism of VC is not merely a consequence of a high-phosphorous and -calcium milieu, but also occurs via delicate and well-organized biologic processes, including an imbalance between osteochondrogenic signaling and anticalcific events. In addition to traditionally established osteogenic signaling, dysfunctional calcium homeostasis is prerequisite in the development of VC. Moreover, loss of defensive mechanisms, by microorganelle dysfunction, including hyper-fragmented mitochondria, mitochondrial oxidative stress, defective autophagy or mitophagy, and endoplasmic reticulum (ER) stress, may all contribute to VC. To facilitate the understanding of vascular calcification, across any number of bioscientific disciplines, we provide this review of a detailed updated molecular mechanism of VC. This encompasses a vascular smooth muscle phenotypic of osteogenic differentiation, and multiple signaling pathways of VC induction, including the roles of inflammation and cellular microorganelle genesis.

The pathogenesis of vascular calcification (VC) in diabetes mellitus (DM) has not been completely elucidated. VC often occur in patients with DM and chronic kidney disease (CKD). The incidence of VC in diabetic patients is more frequent than in nondiabetic patients, which is an important cause of cardiovascular (CV) morbidity and mortality. VC is a progressive transformation of the vascular wall; it results from an active and complex phenomenon affecting particularly the vascular smooth muscle cells (VSMCs). It leads to a change in the phenotype of the VSMCs towards an osteoblastic-like phenotype. DM is associated with specific risk factors in addition to hyperglycemia, such as increased oxidative stress, proinflammatory state, hypertension, and chronic kidney disease (CKD) promoting endothelial dysfunction. This article provides an overview and update of the pathophysiological data on the role of DM in VC progression.

At the early stage of chronic kidney disease (CKD), the systemic mineral metabolism and bone composition start to change. This alteration is known as chronic kidney disease-mineral bone disorder (CKD-MBD). It is well known that the bone turnover disorder is the most common complication of CKD-MBD. Besides, CKD patients usually suffer from vascular calcification (VC), which is highly associated with mortality. Many factors regulate the VC mechanism, which include imbalances in serum calcium and phosphate, systemic inflammation, RANK/RANKL/OPG triad, aldosterone, microRNAs, osteogenic transdifferentiation, and effects of vitamins. These factors have roles in both promoting and inhibiting VC. Patients with CKD usually have bone turnover problems. Patients with high bone turnover have increase of calcium and phosphate release from the bone. By contrast, when bone turnover is low, serum calcium and phosphate levels are frequently maintained at high levels because the reservoir functions of bone decrease. Both of these conditions will increase the possibility of VC. In addition, the calcified vessel may secrete FGF23 and Wnt inhibitors such as sclerostin, DKK-1, and secreted frizzled-related protein to prevent further VC. However, all of them may fight back the inhibition of bone formation resulting in fragile bone. There are several ways to treat VC depending on the bone turnover status of the individual. The main goals of therapy are to maintain normal bone turnover and protect against VC.

Vascular calcification (VC) is a biological phenomenon characterized by an accumulation of calcium and phosphate deposits within the walls of blood vessels causing the loss of elasticity of the arterial walls. VC plays a crucial role in the incidence and progression of chronic kidney disease (CKD), leading to a significant increase in cardiovascular mortality in these patients. Different conditions such as age, sex, dyslipidemia, diabetes, and hypertension are the main risk factors in patients affected by chronic kidney disease. However, VC may occur earlier and faster in these patients if it is associated with new or non-traditional risk factors such as oxidative stress, anemia, and inflammation. In chronic kidney disease, several pathophysiological processes contribute to vascular calcifications, including osteochondrogenic differentiation of vascular cells, hyperphosphatemia and hypercalcemia, and the loss of specific vascular calcification inhibitors including pyrophosphate, fetuin-A, osteoprotegerin, and matrix GLA protein. In this review we discuss the main traditional and non-traditional risk factors that can promote VC in patients with kidney disease. In addition, we provide an overview of the main pathogenetic mechanisms responsible for VC that may be crucial to identify new prevention strategies and possible new therapeutic approaches to reduce cardiovascular risk in patients with kidney disease.

Calcification of the vessel wall contributes to high cardiovascular morbidity and mortality. Vascular calcification (VC) is a systemic disease with multifaceted contributing and inhibiting factors in an actively regulated process. The exact underlying mechanisms are not fully elucidated and reliable treatment options are lacking. Due to the complex pathophysiology, various research models exist evaluating different aspects of VC. This review aims to give an overview of the cell and animal models used so far to study the molecular processes of VC. Here, in vitro cell culture models of different origins, ex vivo settings using aortic tissue and various in vivo disease-induced animal models are summarized. They reflect different aspects and depict the (patho)physiologic mechanisms within the VC process.

Vascular calcification (VC) describes the pathophysiological phenotype of calcium apatite deposition within the vascular wall, leading to vascular stiffening and the loss of compliance. VC is never benign; the presence and severity of VC correlate closely with the risk of myocardial events and cardiovascular mortality in multiple at-risk populations such as patients with diabetes and chronic kidney disease. Mitochondrial dysfunction involving each of vascular wall constituents (endothelia and vascular smooth muscle cells (VSMCs)) aggravates various vascular pathologies, including atherosclerosis and VC. However, few studies address the pathogenic role of mitochondrial dysfunction during the course of VC, and mitochondrial reactive oxygen species (ROS) seem to lie in the pathophysiologic epicenter. Superoxide dismutase 2 (SOD2), through its preferential localization to the mitochondria, stands at the forefront against mitochondrial ROS in VSMCs and thus potentially modifies the probability of VC initiation or progression. In this review, we will provide a literature-based summary regarding the relationship between SOD2 and VC in the context of VSMCs. Apart from the conventional wisdom of attenuating mitochondrial ROS, SOD2 has been found to affect mitophagy and the formation of the autophagosome, suppress JAK/STAT as well as PI3K/Akt signaling, and retard vascular senescence, all of which underlie the beneficial influences on VC exerted by SOD2. More importantly, we outline the therapeutic potential of a novel SOD2-targeted strategy for the treatment of VC, including an ever-expanding list of pharmaceuticals and natural compounds. It is expected that VSMC SOD2 will become an important druggable target for treating VC in the future.

Vascular calcification (VC) is a pathological condition frequently observed in cardiovascular diseases. Primary factors contributing to VC are osteogenic differentiation of vascular smooth muscle and hydroxyapatite deposition. Targeted autophagy (a lysosome-mediated mechanism for degradation/recycling of unnecessary cellular components) is a useful approach for inhibiting VC and promoting vascular cell health. Calycosin has been shown to alleviate atherosclerosis by enhancing macrophage autophagy, but its therapeutic effect on VC has not been demonstrated. Using an in vitro model (rat thoracic aortic smooth muscle cell line A7r5), we demonstrated effective inhibition of VC using calycosin (the primary flavonoid component of astragalus), based on the enhancement of autophagic flux. Calycosin treatment activated AMPK/mTOR signaling to induce initiation of autophagy and restored mTORC1-dependent autophagosome–lysosome fusion in late-stage autophagy by promoting soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex formation, thereby preventing stoppage of autophagy in calcified cells. Calycosin substantially reduced degrees of both osteogenic differentiation and calcium deposition in our VC cell model by enhancing autophagy. The present findings clarify the mechanism whereby calycosin mitigates autophagy stoppage in calcified smooth muscle cells and provide a basis for effective VC treatment via autophagy enhancement.

Le premier objectif de ce travail était d'identifier les miRs associés aux calcifications vasculaires (CV), de caractériser leur implication dans la minéralisation des CMLVs, et de déterminer leurs gènes cibles. Le second objectif était d’étudier les mécanismes de l’hétérogénéité artérielle en comparant le phénotype des CMLVs carotides et fémorales, et leur réponse aux stimuli pro-athérosclérotiques. Premièrement, nous avons utilisé des artères athéromateuses humaines calcifiées et non calcifiées (Biocoll.ECLAGEN) pour identifier les miRs associés aux CV en combinant une analyse miRNomique (puces microfluidiques) et transcriptomique pour sélectionner des miRs candidats et leurs gènes cibles prédits. Nous avons ensuite validé le rôle fonctionnel des miRs candidats dans la minéralisation cellulaire des CMLVs humaines aortiques. Deuxièmement, nous avons extrait des CMLVs d’artères carotides et fémorales saines (Biocoll.ECLA-H) pour étudier les différences phénotypiques (marqueurs contractiles/inflammatoires, migration, contractilité, captation des lipides) à l’état basal et après stimulation par des cytokines pro-inflammatoires (IL1β, IL6) ou pro-fibrosantes (TGFβ et PDGF). Notre étude a d’abord permis l’identification de 12 miRs associés aux CV. Parmi eux, nous avons montré que l'expression des miR136, miR155 et miR183 était régulée pendant la minéralisation des CMLVs, que leur surexpression induisait la minéralisation des CMLVs et des modifications phénotypiques transcriptionnelles. L'analyse croisée a conduit à l'identification des voies CD73 et Smad3 comme gènes cibles prédits responsables de la fonction pro-minéralisante du miR155. Dans un deuxième temps, l’étude phénotypique comparative des CMLVs carotides et fémorales nous a permis de montrer certaines différences transcriptionnelles, l’expression des marqueurs d’activation (ICAM-1, VCAM-1) était supérieure dans le territoire carotidien, l’expression des marqueurs contractiles (ACTA2, SM22α, SMMHC) était supérieure dans le territoire fémoral. Les expériences préliminaires d’analyse de contractilité et de réponse au stress lipidique suggéraient une tendance à une contractilité et une captation de lipides plus importante dans le territoire fémoral. Nous n’avons pas montré de différence lors de l’analyse des switch phénotypiques et de la migration cellulaire. Ces résultats montrent le bénéfice potentiel de l'inhibition du miR155 pour limiter le développement des calcifications vasculaires dans les lésions athéromateuses des artères périphériques
The first objective of this work was to identify the miRs associated with vascular calcification (VC), to characterise their involvement in the mineralisation of VSMCs, and to determine their target genes. The second objective was to study the mechanisms of arterial heterogeneity by comparing the phenotype of carotid and femoral VSMCs and their response to pro-atherosclerotic stimuli. Firstly, we used calcified and non-calcified human atheromatous arteries (Biocoll.ECLAGEN) to identify VC-associated miRs by combining miRNomic (microfluidic arrays) and transcriptomic analysis to select candidate miRs and their predicted target genes. We then validated the functional role of candidate miRs in cell mineralisation of human aortic VSMCs. Secondly, we extracted VSMCs from healthy carotid and femoral arteries (Biocoll.ECLA-H) to study phenotypic differences (contractile/inflammatory markers, migration, contractility, lipid uptake) in the basal state and after stimulation with pro-inflammatory (IL1β, IL6) or pro-fibrotic cytokines (TGFβ and PDGF). In our study, we first identified 12 miRs associated with VC. Among them, we showed that the expression of miR136, miR155 and miR183 was regulated during VSMC mineralisation and that their overexpression induced VSMC mineralisation and phenotypic transcriptional changes. Cross-analysis led to the identification of the CD73 and Smad3 pathways as predicted target genes responsible for the pro-mineralising function of miR155. Secondly, a comparative phenotypic study of carotid and femoral VSMCs allowed us to demonstrate several transcriptional differences, with higher expression of activation markers (ICAM-1, VCAM-1) in the carotid territory and higher expression of contractile markers (ACTA2, SM22α, SMMHC) in the femoral territory. Preliminary experiments analysing contractility and response to lipid stress suggested a trend towards greater contractility and lipid uptake in the femoral territory. No difference was observed when phenotypic switches and cell migration were analysed. These results demonstrate the potential benefit of miR155 inhibition in limiting the development of VC in atheromatous lesions of peripheral arteries

Vascular calcification (VC) is a common feature of patients with advanced CKD and it could be, at least in part, the cause of increased cardiovascular mortality in these patients. From a morphologic point of view, there are at least two types of pathologic calcium phosphate deposition in the arterial wall—namely, intima calcification (mostly associated with atherosclerotic plaques) and media calcification (associated with stiffening of the vasculature, resulting in significantly adverse cardiovascular outcomes). Although VC was viewed initially as a passive phenomenon, it appears to be a cell-mediated, dynamic, and actively regulated process that closely resembles the formation of normal bone tissue, as discovered recently. VC seems to be the result of the dysregulation of the equilibrium between promoters and inhibitors. The determinants are mostly represented by altered calcium and phosphorus metabolism, secondary hyperparathyroidism, vitamin D excess, high fibroblast growth factor 23, and high levels of indoxyl sulphate or leptin; meanwhile, the inhibitors are vitamin K, fetuin A, matrix G1a protein, osteoprotegerin, and pyrophosphate. A number of non-invasive imaging techniques are available to investigate cardiac and vascular calcification: plain X-rays, to identify macroscopic calcifications of the aorta and peripheral arteries; two-dimensional ultrasound for investigating the calcification of carotid arteries, femoral arteries, and aorta; echocardiography, for assessment of valvular calcification; and, of course, computed tomography technologies, which constitute the gold standard for quantification of coronary artery and aorta calcification. All these methods have a series of advantages and limitations. The treatment/ prevention of VC is currently mostly around calcium-mineral bone disease interventions, and unproven. There are interesting hypotheses around vitamin K, Magnesium, sodium thiosulphate and other potential agents.

Cardiovascular disease is the primary cause of morbidity and mortality in chronic kidney disease (CKD) population, particularly in end stage renal disease (ESRD). This could be explained in part due to the presence of traditional cardiovascular risk factors, such as older age, hypertension, dyslipidemia and diabetes, but is also associated with nontraditional cardiovascular risk factors related to CKD, like inflammation, anemia, abnormal calcium and phosphate metabolism and extracellular fluid volume overload, which may contribute to intimal or medial wall arterial calcification. Vascular calcification (VC) is a dynamic process, resulting from the dysregulation of the balance of molecules that promote and those that inhibit this course. It is important for clinicians to both acknowledge and recognize the pathways and risk factors of VC in order to improve cardiovascular health in CKD patients. This chapter will focus on the biology of VC, the association with CKD, risk factor modification, screening and prevention of VC and cardiovascular disease in CKD patients.