Mechanisms Of Vascular Calcification Research Articles

HDAC2 counteracts vascular calcification by activating autophagy in chronic kidney disease.

Vascular calcification is a major risk factor for cardiovascular disease mortality, with a significant prevalence in chronic kidney disease (CKD). Pharmacological inhibition of histone acetyltransferase has been proven to protect against from vascular calcification. However, the role of Histone Deacetylase 2 (HDAC2) and molecular mechanisms in vascular calcification of CKD remains unknown. An invivo model of CKD was established using mouse fed with a high adenine and phosphate diet, and an invitro model was produced using human aortic vascular smooth muscle cells (VSMCs) stimulated with β-glycerophosphate (β-GP). HDAC2 expression was found to be reduced in medial artery of CKD mice and β-GP-induced VSMCs. Overexpression of HDAC2 attenuated OPN and OCN upregulation, α-SMA and SM22α downregulation, and calcium deposition in aortas of CKD. The invitro results also demonstrated that β-GP-induced osteogenic differentiation was inhibited by HDAC2. Furthermore, we found that HDAC2 overexpression caused an increase in LC3II/I, a decrease in p62, and an induction of autophagic flux. Inhibition of autophagy using its specific inhibitor 3-MA blocked HDAC2's protective effect on osteogenic differentiation in β-GP-treated VSMCs. Taken together, these results suggest that HDAC2 may protect against vascular calcification by the activation of autophagy, laying out a novel insight for the molecular mechanism in vascular calcification of CKD.

Plaque‐Specific Adhesive Balloons Coated with Calcium Phosphate Nanoparticles Loaded with Rapamycin for Atherosclerosis Therapy

AbstractDrug‐coated balloons (DCBs), serving as a superior alternative to stents, are at the cutting edge of clinical innovations in atherosclerosis management. Nevertheless, the prevalent high flow rates in arterial vascular result in short drug residence times, significantly compromising DCBs’ therapeutic effectiveness. Drawing inspiration from the mechanisms of vascular calcification, a rapamycin‐loaded calcium phosphate nanoparticle (CaP@Rapa) coating for balloons is pioneered. This coating functions as a potent drug anchor in arteries, facilitating the adhesion of rapamycin to plaques and thereby enhancing the local concentration of the rapamycin. To evaluate its therapeutic efficacy in vivo, the rabbit iliac artery atherosclerosis model is innovatively developed, which authentically mirrors the pathological progression of atherosclerosis in humans. The enhanced localized rapamycin retention, along with its pH‐sensitive sustained release characteristics, culminate in substantial reductions in plaque volume, a decrease in intimal hyperplasia, and mitigation of local inflammation in model rabbits. To further substantiate the translational potential of CaP@Rapa balloons, the research on the pig coronary atherosclerosis model is expanded, which yielded results solidifying the clinical promise of CaP@Rapa balloons. In summary, this research not only offers a more effective and reliable alternative to traditional DCB but also paves the way for further clinical trials.

Relationship between vascular calcification, osteoporosis and systemic inflammation

A lot of patients with coronary heart disease often suffer from vascular calcification. In many cases it is accompanied by harmful cardiovascular events. The modern ideas of the relationship between osteoporosis, vascular calcification and inflammation, the general mechanisms of development of vascular calcification and low bone mineral density are discussed. Despite a growing number of studies concerning the combined pathology of the cardiovascular and skeletal systems, a causal relationship between vascular calcification and a decrease in bone mass has not yet been established. Moreover, there is insufficient data on the effect of inflammation on ectopic calcification. Based on the analysis of available clinical and experimental studies, this review describes the main pathogenetic mechanisms of vascular calcification in coronary atherosclerosis. The influence of calcium and vitamin D medicines on the development of vascular calcification is discussed in this article. The author’s attention is focused on early and long-term consequences of percutaneous coronary intervention and coronary bypass surgery in patients with vascular calcification.

Antihypertensive treatment with hydrochlorothiazide-hydralazine combination aggravates medial vascular calcification in CKD rats with mineral bone disorder.

Arterial stiffness and medial vascular calcification, leading to isolated systolic blood pressure (BP), are major cardiovascular risk factors in patients with chronic kidney disease (CKD) and mineral bone disorders (MBD). The impact of BP on MBD-induced medial vascular calcification in CKD remains uncertain. We investigated whether BP reduction improves arterial stiffness and medial vascular calcification in a rat model of CKD-MBD. CKD was induced in Wistar rats by subtotal nephrectomy. Then, MBD was generated by a Ca/P-rich diet with calcitriol supplementation to induce medial vascular calcification. Two antihypertensive treatments were evaluated: (1) the angiotensin AT1 receptor antagonist losartan, and (2) the combination of the thiazide diuretic hydrochlorothiazide and the direct vasodilator hydralazine (HCTZ/HY). After 5 weeks, mean BP (MBP), pulse pressure (PP), and pulse wave velocity (PWV) were determined. Vascular calcification was assessed in the thoracic aorta. While MBP was similar in CKD-MBD and control CKD rats, PP and PWV were increased in CKD-MBD rats. The heightened arterial stiffness in CKD-MBD rats was associated with diffused medial calcification along the thoracic aorta. Although both losartan and HCTZ/HY reduced MBP in CKD-MBD rats, losartan did not affect PP and PWV nor medial vascular calcification, whereas HCTZ/HY, unexpectedly, further increased arterial stiffness and medial vascular calcification. In the rat model of CKD-MBD, antihypertensive treatment with losartan did not affect arterial stiffness or medial vascular calcification. However, HCTZ/HY treatment aggravated arterial stiffness and vascular calcification despite a similar reduction of MBP, suggesting a blood pressure-independent mechanism for vascular calcification.

Pathophysiology and Clinical Impacts of Chronic Kidney Disease on Coronary Artery Calcification

The global prevalence of chronic kidney disease (CKD) has increased in recent years. Adverse cardiovascular events have become the main cause of life-threatening events in patients with CKD, and vascular calcification is a risk factor for cardiovascular disease. Vascular calcification, especially coronary artery calcification, is more prevalent, severe, rapidly progressive, and harmful in patients with CKD. Some features and risk factors are unique to vascular calcification in patients with CKD; the formation of vascular calcification is not only influenced by the phenotypic transformation of vascular smooth muscle cells, but also by electrolyte and endocrine dysfunction, uremic toxin accumulation, and other novel factors. The study on the mechanism of vascular calcification in patients with renal insufficiency can provide a basis and new target for the prevention and treatment of this disease. This review aims to illustrate the impact of CKD on vascular calcification and to discuss the recent research data on the pathogenesis and factors involved in vascular calcification, mainly focusing on coronary artery calcification, in patients with CKD.

Meet the First Authors

HomeCirculation ResearchVol. 132, No. 4Meet the First Authors Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBMeet the First Authors Originally published16 Feb 2023https://doi.org/10.1161/RES.0000000000000596Circulation Research. 2023;132:398–399is related toADAR1 Non-Editing Function in Macrophage Activation and Abdominal Aortic AneurysmApolipoprotein Proteomics for Residual Lipid-Related Risk in Coronary Heart DiseaseCirculating Extracellular Vesicle-Propagated microRNA Signature as a Vascular Calcification Factor in Chronic Kidney DiseaseCNP Promotes Antiarrhythmic Effects via Phosphodiesterase 2CNP Activates PDE2 to Reduce Arrhythmia (p 400)Download figureDownload PowerPointEleder Cachorro is a PhD student at the Institute of Pharmacology and Toxicology (TU Dresden, Germany) under the supervision of Dr Ali El-Armouche and Dr Susanne Kämmerer, where he studies the role of PDE2 in cardiovascular disease. He studied Biochemistry and Molecular Biology at the University of the Basque Country (EHU, Basque Country), where he obtained his BS. He then earned his MS in the Medical Biotechnology department of the Jagiellonian University of Krakow (UJ, Poland). In the laboratory of Dr Jozef Dulak, he collaborated in the generation of isogenic human pluripotent cell lines for in vitro modelling of HNF1A-MODY monogenic diabetes.Macrophage ADAR1 in AAA (p e78)Download figureDownload PowerPointDr Dunpeng Cai is a postdoctoral fellow in the Department of Surgery at the University of Missouri. After graduating from Southern Medical University, he joined Dr Shi-you Chen’s Lab and earned his PhD in 2021 from the Department of Medical Pharmacology and Physiology at the University of Missouri. Dr Cai’s main research interest is the molecular mechanisms underlying the development of cardiovascular diseases, including aortic aneurysm, atherosclerosis and stroke. Through innovation and hardwork, he wishes to establish landmark discoveries which can provide cures for patients. To achieve this goal, he has been developing his skills and capabilities in molecular and cell biology, mouse microsurgery, computer-aided drug design and bioinformatics. Outside of work, he enjoys spending time with family.sEVs Accelerate Vascular Calcification in CKD (p 415)Download figureDownload PowerPointDr Takaaki Koide was born and raised in Tokyo, Japan. He earned his MD from Asahikawa Medical University. He is currently a PhD student in the Department of Nephrology at Tokyo Medical and Dental University (his mentors: Prof. Shinichi Uchida and Shintaro Mandai). His research focuses on the mechanism of vascular calcification caused by chronic kidney disease. He is interested in utilizing non-coding RNAs as a therapeutic modality to treat extra-renal complications of chronic kidney disease. In his leisure time, he enjoys sports, traveling and craft beer.Apolipoprotein Proteomics for Heart Disease Risk (p 452)Download figureDownload PowerPointDr Robert Clarke is a Professor of Epidemiology and Public Health Medicine at the Clinical Trial Service Unit (CTSU), Nuffield Department of Population Health, University of Oxford. He qualified in medicine at the National University of Ireland in 1979. He worked in internal medicine and cardiology in Ireland for 10 years and clinical pharmacology at Vanderbilt University, Nashville, USA for 2 years. He joined University of Oxford in 1991 and specialized in Cardiovascular Epidemiology. Robert leads a research program on observational and genetic analyses assessing the importance of lifestyle factors, blood pressure, blood lipids, genes and proteomic biomarkers for cardiovascular diseases. Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesADAR1 Non-Editing Function in Macrophage Activation and Abdominal Aortic AneurysmDunpeng Cai, et al. Circulation Research. 2023;132:e78-e93Apolipoprotein Proteomics for Residual Lipid-Related Risk in Coronary Heart DiseaseRobert Clarke, et al. Circulation Research. 2023;132:452-464Circulating Extracellular Vesicle-Propagated microRNA Signature as a Vascular Calcification Factor in Chronic Kidney DiseaseTakaaki Koide, et al. Circulation Research. 2023;132:415-431CNP Promotes Antiarrhythmic Effects via Phosphodiesterase 2Eleder Cachorro, et al. Circulation Research. 2023;132:400-414 February 17, 2023Vol 132, Issue 4 Advertisement Article InformationMetrics © 2023 American Heart Association, Inc.https://doi.org/10.1161/RES.0000000000000596PMID: 36795849 Originally publishedFebruary 16, 2023 PDF download Advertisement

Oleoylethanolamide alleviates hyperlipidaemia-mediated vascular calcification via attenuating mitochondrial DNA stress triggered autophagy-dependent ferroptosis by activating PPARα

Vascular calcification, a prevalent pathological alteration in metabolic syndromes, is tightly related with cardiometabolic risk events. Ferroptosis, a newly iron-dependent programmed cell death, induced by palmitic acid (PA), the major saturated free fatty acid in hyperlipidemia, is a vital mechanism of vascular calcification. Recent studies reported that ferroptosis is a distinctive type of cell death dependent on autophagy, with the lipotoxicity of PA on cell viability being closely linked with autophagy. Oleoylethanolamide (OEA), an endogenous bioactive mediator of lipid homeostasis, exerts vascular protection against intimal calcification, atherosclerosis; however, its beneficial effect on vascular smooth muscle cell (VSMC)-associated medial calcification has not been investigated. Our aim was to characterize the effect of OEA on vascular calcification and ferroptosis of VSMCs under hyperlipidaemia/PA exposure. In vivo, vascular calcification model was induced in rats by high-fat diet and vitamin D3 plus nicotine; in vitro, VSMCs ferroptosis was induced by PA or plus β-glycerophosphate mimicking vascular calcification. The calcium deposition in hyperlipidaemia-mediated rat thoracic aortas, the PA-induced ferroptosis and subsequent calcium deposition in VSMCs, were suppressed by OEA treatment. Additionally, CGAS-STING1-induced ferritinophagy, the main molecular mechanism of PA-triggered ferroptosis of VSMCs, was activated by mitochondrial DNA damage; however, early administration of OEA alleviated these phenomena. Intriguingly, overexpression of peroxisome proliferator activated receptor alpha (PPARα) contributed to a decrease in PA-induced ferroptosis, whereas PPARɑ knockdown inhibited the OEA-mediated anti-ferroptotic effects. Collectively, our study demonstrated that OEA serves as a prospective candidate for the prevention and treatment of vascular calcification in metabolic abnormality syndromes.

Serum Carboxylated and Undercarboxylated Osteocalcin association with Coronary Atherosclerosis Disease and Cardiovascular Risk Markers in: Analysis of a Syrian Male Cohort

Background: New assumption concerning association of osteocalcin and Vascular calcification has emerged in reaction to observations that the mechanism of vascular calcification resembles that of bone mineralization, thus linking bone and the vasculature. However, studies reported contrasting results about the association between osteocalcin and atherosclerosis. This study was designed to evaluate capacity relationships among different forms of circulating osteocalcin and cardiovascular risk markers in male with coronary atherosclerosis. Methods: A cross-sectional study was conducted on 58 male patients, divided into two groups according to the severity of coronary artery disease (CAD), as determined by coronary angiography assessment: Early coronary atherosclerosis (ECA), n=20, patients with mild CAD (<50% stenosis in any major epicardial arteries), and late coronary atherosclerosis (LCA), n=38, patients with severe, multivessel CAD (>50% stenosis in at least one or more major epicardial arteries). The healthy control (HC) group included 26 healthy male subjects. Carboxylated (cOC) and ucOC were measured using ELISA technique. Results: We observed significantly lower ucOC levels in both stages of cardiovascular disease (CVD) (ECA and LCA) compared to the HC group (2.34±2.23 and 2.48±1.60 vs 6.65±1.78ng/mL, P<0.01). ucOC was inversely correlated with an increasing number of cardiovascular risk factors (CVRFs). Moreover, ucOC levels were markedly reduced in high-fasting plasma glucose (FPG) groups (IFG and T2DM-threshold level), compared to the normal FPG group (NG). cOC levels were higher in the IFG group, compared to the normal FPG group (8.50±4.76 vs 7.13±3.13ng/mL, p=0.008) possibly predicting such condition. Conclusions: In the present study, patients with coronary atherosclerosis, regardless of the onset of stenosis, showed lower ucOC levels which were inversely correlated with an increasing number of CVRFs. Moreover, ucOC levels were markedly reduced in high-FPG groups. Serum ucOC may be considered as a potential biomarker for coronary atherosclerosis disease and therefore its measurement may help to establish preventive and therapeutic approaches. Moreover, cOC may be associated with a high alert for diabetes at the IFG stage, but not when the disease progresses to diabetes.

MiR-708-5p/Pit-1 axis mediates high phosphate-induced calcification in vascular smooth muscle cells via Wnt8b/β-catenin pathway.

Recently, the underlying mechanism of vascular calcification (VC) has been partially elucidated. However, it is still high incidence, and no effective treatment has been found. This study aims at figuring out the underlying mechanisms of microRNA-708-5p (miR-708-5p)/sodium-phosphate transporter 1 (Pit-1) axis in high phosphate (HP)-induced VC of T/G HA-VSMCs. Alizarin Red S staining was used to evaluate calcium salt deposition, and the activity of alkaline phosphatase (ALP) was determined by measuring the absorbance at 405 nm. RT-qPCR and Western blot were performed to assess the levels of miR-708-5p and Pit-1, the levels of ALP, Pit-1, β-catenin, glycogen synthesis kinase 3 β (GSK3β), and p-GSK3β proteins, respectively. The interaction between miR-708-5p and Pit-1 was validated by luciferase reporter assay. Our findings illustrated that miR-708-5p was downregulated and Pit-1was upregulated in HP-induced VC. MiR-708-5p mimics inhibited HP-induced VC. Further experiments demonstrated that miR-708-5p targets Pit-1. In addition, miR-708-5p inactivates the Wnt8b/β-catenin pathway via targeting Pit-1 to reduce HP-induced VC. MiR-708-5p has a crucial effect on VC via targeting Pit-1 and inhibiting Wnt8b/β-catenin pathway, it may serve as a new target for VC treatment.

Vascular Calcification in Chronic Kidney Disease: An Update and Perspective.

Chronic kidney disease is a devastating condition resulting from irreversible loss of nephron numbers and function and leading to end-stage renal disease and mineral disorders. Vascular calcification, an ectopic deposition of calcium-phosphate salts in blood vessel walls and heart valves, is an independent risk factor of cardiovascular morbidity and mortality in chronic kidney disease. Moreover, aging and related metabolic disorders are essential risk factors for chronic kidney disease and vascular calcification. Marked progress has been recently made in understanding and treating vascular calcification in chronic kidney disease. However, there is a paucity of systematic reviews summarizing this progress, and investigating unresolved issues is warranted. In this systematic review, we aimed to overview the underlying mechanisms of vascular calcification in chronic kidney diseases and discuss the impact of chronic kidney disease on the pathophysiology of vascular calcification. Additionally, we summarized potential clinical diagnostic biomarkers and therapeutic applications for vascular calcification with chronic kidney disease. This review may offer new insights into the pathogenesis, diagnosis, and therapeutic intervention of vascular calcification.

Biomarkers of vascular calcification: their relationship with diseases of the cardiovascular system and their importance in clinical practice

The literature review highlights the results of the most recent foreign and Russian studies on topical problems of vascular calcification with an emphasis on the relationship between some biochemical markers of vascular calcification (in priority osteoprotegerin and osteopontin) with cardiovascular disease and other associated conditions. Including some provisions of the reviewed studies help to clarify the pathophysiology mechanisms of vascular calcification. And it should also be noted that many aspects of the reviewed studies are directly related to a clinical practice. The purpose of this review is to generalize and systematize current knowledge about the contribution of vascular calcification biochemical markers to vascular tunic pathology, which finally leads to cardiovascular events. To prepare it, the databases PubMed, Google Scholar, ScienceDirect, MDPI, Hindawi, Oxford Academic were used.

Vascular Calcification Mechanisms: Updates and Renewed Insight into Signaling Pathways Involved in High Phosphate-Mediated Vascular Smooth Muscle Cell Calcification.

Vascular calcification (VC) is associated with aging, cardiovascular and renal diseases and results in poor morbidity and increased mortality. VC occurs in patients with chronic kidney disease (CKD), a condition that is associated with high serum phosphate (Pi) and severe cardiovascular consequences. High serum Pi level is related to some pathologies which affect the behaviour of vascular cells, including platelets, endothelial cells (ECs) and smooth muscle cells (SMCs), and plays a central role in promoting VC. VC is a complex, active and cell-mediated process involving the transdifferentiation of vascular SMCs to a bone-like phenotype, systemic inflammation, decreased anti-calcific events (loss of calcification inhibitors), loss in SMC lineage markers and enhanced pro-calcific microRNAs (miRs), an increased intracellular calcium level, apoptosis, aberrant DNA damage response (DDR) and senescence of vascular SMCs. This review gives a brief overview of the current knowledge of VC mechanisms with a particular focus on Pi-induced changes in the vascular wall important in promoting calcification. In addition to reviewing the main findings, this review also sheds light on directions for future research in this area and discusses emerging pathways such as Pi-regulated intracellular calcium signaling, epigenetics, oxidative DNA damage and senescence-mediated mechanisms that may play critical, yet to be explored, regulatory and druggable roles in limiting VC.

Plasma Exosomes Derived From Patients With End-Stage Renal Disease and Renal Transplant Recipients Have Different Effects on Vascular Calcification.

End-stage renal disease (ESRD) patients usually develop extensive and progressive vascular calcification, and lots of calcification inhibitors as well as procalcifying factors are involved in the process. However, the mechanisms of vascular calcification in ESRD patients are still ill-defined. In the present study, we found that the plasma exosomes derived from ESRD patients (ESRD-Ex) promoted calcification of vascular smooth muscle cells (VSMCs) significantly, while plasma exosomes from renal transplant recipients (RTR-Ex) could partially attenuate VSMCs calcification. Moreover, the protein concentration of ESRD-Ex was significantly higher than plasma exosomes from the normal health control group (Nor-Ex) and RTR-Ex, and the content of both matrix gla protein (MGP) and Fetuin-A, the calcification inhibitors, were prominently lower in ESRD-Ex than those in Nor-Ex. The content of Annexin-A2, one of the calcification promoters, was significantly higher in ESRD-Ex and RTR-Ex than that in Nor-Ex. However, bone morphogenetic protein (BMP-2) and receptor activator for nuclear factor-κB ligand (Rankl) had no significant difference among the three groups. In addition, the content of Fetuin-A in RTR-Ex was higher than that in ESRD-Ex, although it was still lower than that in Nor-Ex. Furthermore, the levels of both Fetuin-A and MGP in plasma exosomes were negatively while the levels of Annexin-A2 in plasma exosomes was positively correlated to coronary artery calcification scores (CACS). These results indicated that ESRD-Ex significantly promoted VSMCs calcification, while renal transplantation could partially attenuate the procalcification effect of exosomes. Fetuin-A and MGP were decreased, but Annexin-A2 was increased in ESRD-Ex, and renal transplantation could increase the level of Fetuin-A rather than MGP.

An update on vascular calcification and potential therapeutics.

Pathological calcification is a major cause of cardiovascular morbidities primarily in population with chronic kidney disease (CKD), end stage renal diseases (ERSD) and metabolic disorders. Investigators have accepted the fact that vascular calcification is not a passive process but a highly complex, cell mediated, active process in patients with cardiovascular disease (CVD) resulting from, metabolic insults of bone fragility, diabetes, hypertension, dyslipidemia and atherosclerosis. Over the years, studies have revealed various mechanisms of vascular calcification like induction of bone formation, apoptosis, alteration in Ca-P balance and loss of inhibition. Novel clinical studies targeting cellular mechanisms of calcification provide promising and potential avenues for drug development. The interventions include phosphate binders, sodium thiosulphate, vitamin K, calcimimetics, vitamin D, bisphosphonates, Myoinositol hexaphosphate (IP6), Denosumab and TNAP inhibitors. Concurrently investigators are also working towards reversing or curing pathological calcification. This review focuses on the relationship of vascular calcification to clinical diseases, regulators and factors causing calcification including genetics which have been identified. At present, there is lack of any significant preventive measures for calcifications and hence this review explores further possibilities for drug development and treatment modalities.

Inhibition of extracellular matrix integrity attenuates the early phase of aortic medial calcification in a rodent model

Background and aimsThe mechanism of vascular calcification (VC) resembles that of bone metabolism, and a correlation has frequently been reported between calcification and vascular extracellular matrix (ECM) regulating its integrity; however, the detailed mechanisms remain unclear. In this study, we examined how the vascular ECM, especially collagen metabolism, is involved in the process of VC. MethodsVC was modeled using 5-week-old male Sprague–Dawley rats fed a diet containing warfarin and vitamin K1 (WVK). Additionally, β-aminopropionitrile (BAPN) was administered to inhibit lysyl oxidase (LOX), which is an enzyme that mediates collagen cross-linking. Harvested aortic samples were analyzed by staining with alizarin red (AR), immunohistochemistry (IHC), transmission electron microscopy (TEM), and ex vivo microcomputed tomography (μCT). ResultsRats fed WVK developed increasing numbers of aortic medial calcifications (AMCs) over time. TEM images indicated punctate calcification within collagen fibers in the early phase of AMC. AR staining of translucent samples revealed the distribution and severity of calcification, and these lesions were significantly decreased in the BAPN group. Three-dimensional reconstructed μCT images that allowed the quantification of calcified volumes revealed that BAPN significantly reduced the bulk of calcification. Moreover, IHC showed that both LOX and collagen I were present around the sites of AMC, and thus the IHC-positive area was reduced in the BAPN group compared to the WVK group. ConclusionsThe results indicated that inhibition of LOX by BAPN attenuated AMC, and that collagen metabolism plays a significant role in the early pathogenesis of VC.

The Crosstalk between Calcium Ions and Aldosterone Contributes to Inflammation, Apoptosis, and Calcification of VSMC via the AIF-1/NF-κB Pathway in Uremia.

Vascular calcification is a major complication of maintenance hemodialysis patients. Studies have confirmed that calcification mainly occurs in the vascular smooth muscle cells (VSMC) of the vascular media. However, the exact pathogenesis of VSMC calcification is still unknown. This study shows that the crosstalk between calcium and aldosterone via the allograft inflammatory factor 1 (AIF-1) pathway contributes to calcium homeostasis and VSMC calcification, which is a novel mechanism of vascular calcification in uremia. In vivo results showed that the level of aldosterone and inflammatory factors increased in calcified arteries, whereas no significant changes were observed in peripheral blood. However, the expression of inflammatory factors markedly increased in the peripheral blood of uremic rats without aortic calcification and gradually returned to normal levels with aggravation of aortic calcification. In vitro results showed that there was an interaction between calcium ions and aldosterone in macrophages or VSMC. Calcium induced aldosterone synthesis, and in turn, aldosterone also triggered intracellular calcium content upregulation in macrophages or VSMC. Furthermore, activated macrophages induced inflammation, apoptosis, and calcification of VSMC. Activated VSMC also imparted a similar effect on untreated VSMC. Finally, AIF-1 enhanced aldosterone- or calcium-induced VSMC calcification, and NF-κB inhibitors inhibited the effect of AIF-1 on VSMC. These in vivo and in vitro results suggest that the crosstalk between calcium ions and aldosterone plays an important role in VSMC calcification in uremia via the AIF-1/NF-κB pathway. Local calcified VSMC induced the same pathological process in surrounding VSMC, thereby contributing to calcium homeostasis and accelerating vascular calcification.

MicroRNAs are critical in regulating smooth muscle cell mineralization and apoptosis during vascular calcification.

Vascular calcification refers to the pathological deposition of calcium and phosphate minerals into the vasculature. It is prevalent in atherosclerosis, ageing, type 2 diabetes mellitus and chronic kidney disease, thus, increasing morbidity and mortality from these conditions. Vascular calcification shares similar mechanisms with bone mineralization, with smooth muscle cells playing a critical role in both processes. In the last decade, a variety of microRNAs have been identified as key regulators for the differentiation, phenotypic switch, proliferation, apoptosis, cytokine production and matrix deposition in vascular smooth muscle cells during vascular calcification. Therefore, this review mainly discusses the roles of microRNAs in the pathophysiological mechanisms of vascular calcification in smooth muscle cells and describes several interventions against vascular calcification by regulating microRNAs. As the exact mechanisms of calcification remain not fully elucidated, having a better understanding of microRNA involvement in vascular calcification may give impetus to development of novel therapeutics for the control and treatment of vascular calcification.

SLC37A2, a phosphorus-related molecule, increases in smooth muscle cells in the calcified aorta.

Vascular calcification is major source of cardiovascular disease in patients with chronic kidney disease. Hyperphosphatemia leads to increased intracellular phosphorus influx, which leads to an increase in osteoblast-like cells in vascular smooth muscle cell. PiT-1 transports phosphate in vascular smooth muscle cell. However, the mechanism of vascular calcification is not completely understood. This study investigated candidate phosphorus-related molecules other than PiT-1. We hypothesized that phosphorus-related molecules belonging to the solute-carrier (SLC) superfamily would be involved in vascular calcification. As a result of DNA microarray analysis, we focused on SLC37A2 and showed that mRNA expression of these cells increased on calcified aotic smooth muscle cells (AoSMC). SLC37A2 has been reported to transport both glucose-6-phosphate/phosphate and phosphate/phosphate exchanges. In vitro analysis showed that SLC37A2 expression was not affected by inflammation on AoSMC. The expression of SLC37A2 mRNA and protein increased in calcified AoSMC. In vivo analysis showed that SLC37A2 mRNA expression in the aorta of chronic kidney disease rats was correlated with osteogenic marker genes. Furthermore, SLC37A2 was expressed at the vascular calcification area in chronic kidney disease rats. As a result, we showed that SLC37A2 is one of the molecules that increase with vascular calcification in vitro and in vivo.

Induced osteogenic differentiation of human smooth muscle cells as a model of vascular calcification

Vascular calcification is a severe pathological event in the manifestation of atherosclerosis. Pathogenic triggers mediating osteogenic differentiation of arterial smooth muscle cells (SMC) in humans remain insufficiently understood and are to a large extent investigated in animal models or cells derived thereof. Here, we describe an in vitro model based on SMC derived from healthy and diseased humans that allows to comprehensively investigate vascular calcification mechanisms. Comparing the impact of the commonly used SMC culture media VascuLife, DMEM, and M199, cells were characterised by immunofluorescence, flow cytometry, qPCR, and regarding their contractility and proliferative capacity. Irrespective of the arterial origin, the clinical background and the expansion medium used, all cells expressed typical molecular SMC marker while contractility varied between donors. Interestingly, the ability to induce an osteogenic differentiation strongly depended on the culture medium, with only SMC cultured in DMEM depositing calcified matrix upon osteogenic stimulation, which correlated with increased alkaline phosphatase activity, increased inorganic phosphate level and upregulation of osteogenic gene markers. Our optimized model is suitable for donor-oriented as well as broader screening of potential pathogenic mediators triggering vascular calcification. Translational studies aiming to identify and to evaluate therapeutic targets in a personalized fashion would be feasible.

The Role of Vitamin D in Modulating Mesenchymal Stem Cells and Endothelial Progenitor Cells for Vascular Calcification.

Vascular calcification, which involves the deposition of calcifying particles within the arterial wall, is mediated by atherosclerosis, vascular smooth muscle cell osteoblastic changes, adventitial mesenchymal stem cell osteoblastic differentiation, and insufficiency of the calcification inhibitors. Recent observations implied a role for mesenchymal stem cells and endothelial progenitor cells in vascular calcification. Mesenchymal stem cells reside in the bone marrow and the adventitial layer of arteries. Endothelial progenitor cells that originate from the bone marrow are an important mechanism for repairing injured endothelial cells. Mesenchymal stem cells may differentiate osteogenically by inflammation or by specific stimuli, which can activate calcification. However, the bioactive substances secreted from mesenchymal stem cells have been shown to mitigate vascular calcification by suppressing inflammation, bone morphogenetic protein 2, and the Wingless-INT signal. Vitamin D deficiency may contribute to vascular calcification. Vitamin D supplement has been used to modulate the osteoblastic differentiation of mesenchymal stem cells and to lessen vascular injury by stimulating adhesion and migration of endothelial progenitor cells. This narrative review clarifies the role of mesenchymal stem cells and the possible role of vitamin D in the mechanisms of vascular calcification.