Intravenous transfusion of endothelial progenitor cells that overexpress vitamin D receptor inhibits atherosclerosis in apoE-deficient mice

Cytomegalovirus results in poor graft function via bone marrow-derived endothelial progenitor cells

Introduction

Poor graft function (PGF), characterized by myelosuppression, represents a significant challenge following allogeneic hematopoietic stem cell transplantation (allo-HSCT) with human cytomegalovirus (HCMV) being established as a risk factor for PGF. However, the underlying mechanism remains unclear. Bone marrow endothelial progenitor cells (BM-EPCs) play an important role in supporting hematopoiesis and their dysfunction contributes to PGF development. We aim to explore the effects of CMV on BM-EPCs and its underlying mechanism.

Methods

We investigated the compromised functionality of EPCs derived from individuals diagnosed with HCMV viremia accompanied by PGF, as well as after infected by HCMV AD 169 strain in vitro, characterized by decreased cell proliferation, tube formation, migration and hematopoietic support, and increased apoptosis and secretion of TGF-β1.

Results

We demonstrated that HCMV-induced TGF-β1 secretion by BM-EPCs played a dominant role in hematopoiesis suppression in vitro experiment. Moreover, HCMV down-regulates Vitamin D receptor (VDR) and subsequently activates p38 MAPK pathway to promote TGF-β1 secretion by BM-EPCs.

Discussion

HCMV could infect BM-EPCs and lead to their dysfunction. The secretion of TGF-β1 by BM-EPCs is enhanced by CMV through the activation of p38 MAPK via a VDR-dependent mechanism, ultimately leading to compromised support for hematopoietic progenitors by BM EPCs, which May significantly contribute to the pathogenesis of PGF following allo-HSCT and provide innovative therapeutic strategies targeting PGF.

Four common vitamin D receptor polymorphisms and coronary artery disease susceptibility: A trial sequential analysis

Background

Studies on the susceptibility of vitamin D receptor (VDR) polymorphisms to coronary artery disease (CAD) reached controversial results. We performed this study for a more accurate evaluation between the VDR polymorphisms and CAD susceptibility.

Methods

PubMed, Embase, CNKI, Wan Fang, and VIP databases were searched. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to evaluate the associations. Trial sequential analysis (TSA) was introduced to estimate the positive associations. The potential functions of the VDR polymorphisms were analyzed based on the SNPinfo and ENSEMBL databases.

Results

Thirteen studies were finally included. In the overall analysis, increased CAD risks were observed in the VDR rs1544410 polymorphism and verified by the TSA; for the rs2228570 and rs731236 polymorphisms, significant associations with high heterogeneity were detected; decreased risk was remarkably observed for the rs7975232 polymorphism. In the subgroup analysis, wide associations with reduced heterogeneity were observed in the rs2228570, rs1544410, and rs731236 polymorphisms. The RNAfold analysis indicated the mutant G allele of the rs1544410 polymorphism was easier to disperse from the DNA double helix structure and may have a potential crucial role in the VDR transcription process.

Conclusions

Our analysis supports the role of the rs1544410 polymorphism in the VDR gene as a risk factor for CAD. The VDR rs2228570 and rs731236 polymorphisms were associated with increased CAD risks in the White population. Restrict decreased CAD risk was firstly discovered in the rs7975232 polymorphism.

Limitations

Firstly, the language was restricted to English and Chinese, which will cause the limited number of studies included; secondly, other unknown polymorphisms in VDR polymorphisms could also be associated the CAD susceptibility, and more case-control studies with comprehensive clinical outcomes and GWAS studies were required; thirdly, the rs1544410, rs7975232 and rs731236 polymorphism are in strong LD, haploid factors with CAD risk need to be considered; fourthly, the mechanisms of the VDR polymorphism on the VDR gene or RNA or protein were not discussed enough, further mechanistic studies are required; at last, genetic factor was the one side for CAD susceptibility, the interaction between environmental risk factors should be considered.

Beneficial Role of Vitamin D on Endothelial Progenitor Cells (EPCs) in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of death in the world. Endothelial progenitor cells (EPCs) are currently being explored in the context of CVD risk. EPCs are bone marrow derived progenitor cells involved in postnatal endothelial repair and neovascularization. A large body of evidence from clinical, animal, and in vitro studies have shown that EPC numbers in circulation and their functionality reflect endogenous vascular regenerative capacity. Traditionally vitamin D is known to be beneficial for bone health and calcium metabolism and in the last two decades, its role in influencing CVD and cancer risk has generated significant interest. Observational studies have shown that low vitamin D levels are associated with an adverse cardiovascular risk profile. Still, Mendelian randomization studies and randomized control trials (RCTs) have not shown significant effects of vitamin D on cardiovascular events. The criticism regarding the RCTs on vitamin D and CVD is that they were not designed to investigate cardiovascular outcomes in vitamin D-deficient individuals. Overall, the association between vitamin D and CVD remains inconclusive. Recent clinical and experimental studies have demonstrated the beneficial role of vitamin D in increasing the circulatory level of EPC as well as their functionality. In this review we present evidence supporting the beneficial role of vitamin D in CVD through its modulation of EPC homeostasis.

Vitamin D (1,25-(OH)2D3) Improves Endothelial Progenitor Cells Function via Enhanced NO Secretion in Systemic Lupus Erythematosus

It has been proven that vitamin D was decreased and function of circulating endothelial progenitor cells (EPCs) was injured in systemic lupus erythematosus (SLE) patients. However, the effect of vitamin D on the function of EPCs in vitro and its mechanism need further study. Therefore, we investigated whether vitamin D improved the function of EPCs in vitro. The peripheral blood mononuclear cells of the participants were isolated from SLE patients and control subjects and cultured to EPCs. After the EPCs were treated with vitamin D (1,25-(OH)₂D₃), we evaluated the number, migratory and proliferative activities, and nitric oxide (NO) production of EPCs in vitro and detected vascular endothelial function by flow-mediated dilatation (FMD). We found that vitamin D in a dose-dependent manner improved number and migratory and proliferative activities of EPCs from SLE patients. Additionally, vitamin D upregulated NO production from EPCs in vitro. A significant correlation between the FMD and plasma NO level was found. There was also a correlation between number, migration, and proliferation of EPCs and NO production. Thus, the present findings indicated that vitamin D improved the function of EPCs from SLE patients via NO secretion.

Vitamin D and Cardiovascular Risk: which Implications in Children?

Vitamin D (25OHD) pleiotropic effects are widely recognized and studied. Recently, vitamin D cardiovascular effects are gaining interest, especially in children, although the studies present conflicting data. Some randomized controlled trials (RCTs) have demonstrated that cardiovascular risk markers, such as lipid parameters, inflammation markers, blood pressure, and arterial stiffness, are unaffected by vitamin D supplementation. By contrast, other studies show that low vitamin D levels are associated with higher risk of cardiovascular disease (CVD) and mortality, and support that increased risk of these diseases occurs primarily in people with vitamin D deficiency. An update on these points in pediatric patients is certainly of interest to focus on possible benefits of its supplementation.

Relationship between plasma levels of 25-hydroxyvitamin D and arterial stiffness in elderly Chinese with non-dipper hypertension: An observational study

Elderly individuals with non-dipper hypertension are at high risk of cardiovascular disease because of increased stiffness of peripheral arteries. Since, vitamin D deficiency is prevalent in elderly Chinese. We examined whether reduced plasma levels of 25-hydroxyvitamin D [25(OH)D] may help promote this stiffness.Hypertensive patients at least 60 years old without history of peripheral arterial disease at our hospital were retrospectively divided into dipper and non-dipper groups according to the results of 24-hour ambulatory blood pressure monitoring. Plasma levels of 25(OH)D were measured by enzyme immunoassay. Peripheral arterial stiffness was measured based on the cardio-ankle vascular index (CAVI).Of the 155 patients enrolled, 95 (61.3%) were diagnosed with non-dipper hypertension and these patients had significantly lower plasma levels of 25(OH)D than the 60 patients with dipper hypertension (19.58 ± 5.97 vs 24.36 ± 6.95 nmol/L, P < .01) as well as significantly higher CAVI (8.46 ± 1.65 vs 7.56 ± 1.08 m/s, P < .01). Vitamin D deficiency was significantly more common among non-dipper patients (57.9% vs 31.7%, P < .01). Multivariate regression showed that age and 25(OH)D were independently related to CAVI, with each 1-ng/ml decrease in 25(OH)D associated with a CAVI increase of +0.04 m/s.Non-dipper hypertension is associated with vitamin D deficiency and reduced plasma levels of 25(OH)D. The latter may contribute to stiffening of peripheral arteries, increasing the risk of cardiovascular disease.

Vitamin D as A Protector of Arterial Health: Potential Role in Peripheral Arterial Disease Formation

Atherosclerotic occlusive diseases and aneurysms that affect large and medium-sized arteries outside the cardiac and cerebral circulation are collectively known as peripheral arterial disease (PAD). With a rise in the rate of aging population worldwide, the number of people diagnosed with PAD is rapidly increasing. The micronutrient vitamin D is an important steroid hormone that acts on many crucial cellular mechanisms. Experimental studies suggest that optimal levels of vitamin D have beneficial effects on the heart and blood vessels; however, high vitamin D concentrations have been implicated in promoting vascular calcification and arterial stiffness. Observations from various clinical studies shows that deficiency of vitamin D has been associated with a greater risk of PAD. Epidemiological studies have often reported an inverse relation between circulating vitamin D status measured in terms of 25-hydroxivitamin D [25(OH)D] levels and increased cardiovascular disease risk; however, randomized controlled trials did not show a consistent positive effect of vitamin D supplementation on cardiovascular disease risk or events. Even though PAD shares all the major risk factors with cardiovascular diseases, the effect of vitamin D deficiency in PAD is not clear. Current evidence suggests a strong role of vitamin D in promoting genomic and epigenomic changes. This review summarises the current literature that supports the notion that vitamin D deficiency may promote PAD formation. A better understanding of underlying pathological mechanisms will open up new therapeutic possibilities which is the main unmet need in PAD management. Furthermore, epigenetic evidence shows that a more holistic approach towards PAD prevention that incorporates a healthy lifestyle, adequate exercise and optimal nutrition may be more effective in protecting the genome and maintaining a healthy vasculature.

Vitamin D protects against diabetic nephropathy: Evidence-based effectiveness and mechanism

Vitamin D has been suggested to harbor multiple biological activities, among them the potential of vitamin D in the protection of diabetic nephropathy (DN) has attracted special attention. Both animal studies and clinical trials have documented an inverse correlation between low vitamin D levels and DN risk, and supplementation with vitamin D or its active derivatives has been demonstrated to improve endothelial cell injury, reduce proteinuria, attenuate renal fibrosis, and resultantly retard DN progression. Vitamin D exerts its pharmacological effects primarily via vitamin D receptor, whose activation inhibits the renin-angiotensin system, a key culprit for DN under hyperglycemia. The anti-DN benefit of vitamin D can be enhanced when administrated in combination with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers. Mechanistic studies reveal that pathways relevant to inflammation participate in the pathogenesis of DN, however, consumption of vitamin D-related products negatively regulates inflammatory response at multiple levels, indicated by inhibiting macrophage infiltration, nuclear factor-kappa B (NF-κB) activation, and production of such inflammatory mediators as transforming growth factor-β(TGF-β), monocyte chemoattractant protein 1(MCP-1), and regulated upon activation normal T cell expressed and secreted protein(RANTES). The robust anti-inflammatory property of vitamin D-related products allows them with a promising renoprotective therapeutic option for DN. This review summarizes new advances in our understanding of vitamin D-related products in the DN management.

Role of Vitamin D in Cardiovascular Diseases

Vitamin D is critical in mineral homeostasis and skeletal health and plays a regulatory role in nonskeletal tissues. Vitamin D deficiency is associated with chronic inflammatory diseases, including diabetes and obesity, both strong risk factors for cardiovascular diseases (CVDs). CVDs, including coronary artery disease, myocardial infarction, hypertrophy, cardiomyopathy, cardiac fibrosis, heart failure, aneurysm, peripheral arterial disease, hypertension, and atherosclerosis, are major causes of morbidity and mortality. The association of these diseases with vitamin D deficiency and improvement with vitamin D supplementation suggest its therapeutic benefit. The authors review the findings on the association of vitamin D deficiency and CVDs.

Reduced Vitamin D Receptor on Circulating Endothelial Progenitor Cells: A New Risk Factor of Coronary Artery Diseases

Aim: Endothelial progenitor cells (EPCs) are shown to participate in the pathological processes of atherosclerosis. While Vitamin D and its receptor axis might exert some effects on EPCs' function. But their exact relationship with clinical patients is still elusive, which inspired us to explore the potential association of vitamin D receptor (VDR) expression on circulating EPCs and serum vitamin D levels among patients with coronary artery disease (CAD).

Methods: Two hundred patients with CAD after their admission to hospital and one hundred healthy controls were enrolled. Medical history data were retrieved and fresh blood samples were collected for flow cytometry analysis. VDR expressions on EPCs were evaluated according to the standardized protocol. Logistic regression analysis was used to investigate the potential risk factor of CAD.

Results: CAD patients were found to have lower log₁₀^VDR-MFIs than those of control group, especially for patients with diabetes (p < 0.001). Log₁₀^VDR-MFIs were inversely correlated with glycated hemoglobin (R = −0.472, p < 0.001), and while EPCs challenged with high glucose had lower VDR expression. Multivariate logistic regression analysis revealed that lower log₁₀^VDR-MFIs were independently associated with the risk of CAD (OR = 0.055, p = 0.008).

Conclusion: A significant decrease of VDR expression on circulating EPCs was observed among CAD patients, particularly among those also with diabetes. VDR expression on EPCs was independently negatively correlated with HbA_1c and high glucose decreased EPCs' VDR expression. Low levels of VDR expression on circulating EPCs might serve as a potential risk factor of CAD.