Therapeutic potential of endothelial progenitor cells in cardiovascular diseases

Potential role of endothelial progenitor cells in the pathogenesis and treatment of cerebral aneurysm

Cerebral aneurysm (CA) is a significant health concern that results from pathological dilations of blood vessels in the brain and can lead to severe and potentially life-threatening conditions. While the pathogenesis of CA is complex, emerging studies suggest that endothelial progenitor cells (EPCs) play a crucial role. In this paper, we conducted a comprehensive literature review to investigate the potential role of EPCs in the pathogenesis and treatment of CA. Current research indicates that a decreased count and dysfunction of EPCs disrupt the balance between endothelial dysfunction and repair, thus increasing the risk of CA formation. Reversing these EPCs abnormalities may reduce the progression of vascular degeneration after aneurysm induction, indicating EPCs as a promising target for developing new therapeutic strategies to facilitate CA repair. This has motivated researchers to develop novel treatment options, including drug applications, endovascular-combined and tissue engineering therapies. Although preclinical studies have shown promising results, there is still a considerable way to go before clinical translation and eventual benefits for patients. Nonetheless, these findings offer hope for improving the treatment and management of this condition.

Responses of Endothelial Progenitor Cells to Chronic and Acute Physical Activity in Healthy Individuals

Endothelial progenitor cells (EPCs) are circulating cells of various origins that possess the capacity for renewing and regenerating the endothelial lining of blood vessels. During physical activity, in response to factors such as hypoxia, changes in osmotic pressure, and mechanical forces, endothelial cells undergo intense physiological stress that results in endothelial damage. Circulating EPCs participate in blood vessel repair and vascular healing mainly through paracrine signalling. Furthermore, physical activity may play an important role in mobilising this important cell population. In this narrative review, we summarise the current knowledge on the biology of EPCs, including their characteristics, assessment, and mobilisation in response to both chronic and acute physical activity in healthy individuals.

Combination human umbilical cord perivascular and endothelial colony forming cell therapy for ischemic cardiac injury

Cell-based therapeutics are promising interventions to repair ischemic cardiac tissue. However, no single cell type has yet been found to be both specialized and versatile enough to heal the heart. The synergistic effects of two regenerative cell types including endothelial colony forming cells (ECFC) and first-trimester human umbilical cord perivascular cells (FTM HUCPVC) with endothelial cell and pericyte properties respectively, on angiogenic and regenerative properties were tested in a rat model of myocardial infarction (MI), in vitro tube formation and Matrigel plug assay. The combination of FTM HUCPVCs and ECFCs synergistically reduced fibrosis and cardiomyocyte apoptosis, while promoting favorable cardiac remodeling and contractility. These effects were in part mediated by ANGPT2, PDGF-β, and VEGF-C. PDGF-β signaling-dependent synergistic effects on angiogenesis were also observed in vitro and in vivo. FTM HUCPVCs and ECFCs represent a cell combination therapy for promoting and sustaining vascularization following ischemic cardiac injury.

The Long and Winding Road to Cardiac Regeneration

Cardiac regeneration is a critical endeavor in the treatment of heart diseases, aimed at repairing and enhancing the structure and function of damaged myocardium. This review offers a comprehensive overview of current advancements and strategies in cardiac regeneration, with a specific focus on regenerative medicine and tissue engineering-based approaches. Stem cell-based therapies, which involve the utilization of adult stem cells and pluripotent stem cells hold immense potential for replenishing lost cardiomyocytes and facilitating cardiac tissue repair and regeneration. Tissue engineering also plays a prominent role employing synthetic or natural biomaterials, engineering cardiac patches and grafts with suitable properties, and fabricating upscale bioreactors to create functional constructs for cardiac recovery. These constructs can be transplanted into the heart to provide mechanical support and facilitate tissue healing. Additionally, the production of organoids and chips that accurately replicate the structure and function of the whole organ is an area of extensive research. Despite significant progress, several challenges persist in the field of cardiac regeneration. These include enhancing cell survival and engraftment, achieving proper vascularization, and ensuring the long-term functionality of engineered constructs. Overcoming these obstacles and offering effective therapies to restore cardiac function could improve the quality of life for individuals with heart diseases.

Stem Cell-Derived Exosomes Potential Therapeutic Roles in Cardiovascular Diseases

Owing to myocardial abnormalities, cardiac ailments are considered to be the major cause of morbidity and mortality worldwide. According to a recent study, membranous vesicles that are produced naturally, termed as "exosomes", have emerged as the potential candidate in the field of cardiac regenerative medicine. A wide spectrum of stem cells has also been investigated in the treatment of cardiovascular diseases (CVD). Exosomes obtained from the stem cells are found to be cardioprotective and offer great hope in the treatment of CVD. The basic nature of exosomes is to deal with the intracellular delivery of both proteins and nucleic acids. This activity of exosomes helps us to rely on them as the attractive pharmaceutical delivery agents. Most importantly, exosomes derived from microRNAs (miRNAs) hold great promise in assessing the risk of CVD, as they serve as notable biomarkers of the disease. Exosomes are small, less immunogenic, and lack toxicity. These nanovesicles harbor immense potential as a therapeutic entity and would provide fruitful benefits if consequential research were focused on their upbringing and development as a useful diagnostic and therapeutic tool in the field of medicine.

MRI tracing of ultrasmall superparamagnetic iron oxide nanoparticle‑labeled endothelial progenitor cells for repairing atherosclerotic vessels in rabbits

Endothelial progenitor cells (EPCs) have been discovered to be relevant to the prognosis of cardiovascular diseases. Previous research has demonstrated that EPCs serve vital roles in the occurrence and development of atherosclerosis. Significant improvements have been made in MRI technology and in the experimental use of EPCs for therapeutic angiogenesis and vascular repair. Nevertheless, the migratory, adhesive, proliferative and angiogenic properties of EPCs remain unknown. The aims of the present study were to investigate the potential of using non-invasive monitoring with ultrasmall superparamagnetic iron oxide nanoparticle (USPION)-labeled endothelial progenitor cells (EPCs) after transplantation, and to assess the treatment outcomes in an atherosclerotic rabbit model. EPCs derived from rabbit peripheral blood samples were labeled with USPION-poly-l-lysine (USPION-PLL). The morphology, proliferation, adhesive ability and labeling efficiency of the EPCs were determined by optical and electron microscopy. Moreover, biological activity was assessed by flow cytometry. In addition, T2-weighted image fast spin-echo MRI was used to detect cell labeling. USPION content in the labeled EPCs was determined by Prussian blue staining and scanning electron microscopy. Rabbit atherosclerosis model was established using a high-fat diet. USPION-labeled EPCs were transplanted into rabbits, and in vivo MRI was performed 1 and 7 days after transplantation. It was found that EPCs cultured on Matrigel formed capillary-like structures, and expressed the surface markers CD133, CD31, CD34 and vascular endothelial growth factor receptor 2 (VEGFR2). The optimal USPION concentration was 32 µg/ml, as determined by adhesion and proliferation assays. It was identified that USPION-PLL nanoparticles were 10–20 nm in diameter. Histopathological analysis results indicated that 1 day after transplantation of the labeled EPCs, blue-stained granules were observed in the intima of vascular lesions in rabbit models after Prussian blue staining. Therefore, the present results suggest that USPION-labeled EPCs may play a role in repairing endothelial injury and preventing atherosclerosis in vivo.

miR-324-5p protects against oxidative stress-induced endothelial progenitor cell injury by targeting Mtfr1

Endothelial progenitor cells (EPCs) belong to bone marrow-derived myeloid progenitor cells that have strong proliferative ability. Dysregulation of miRNAs after acute myocardial infarction (AMI) can result in EPCs injury, thus we hypothesize that correction of miRNA expression may contribute to the tolerance of EPCs against oxidative stress. The peripheral blood of healthy volunteers and patients with ST-segment elevation myocardial infarction (STEMI) was clinically collected. EPCs derived from peripheral blood were transfected by miR-324-5p mimic and simultaneously handled with hydrogen peroxide (H₂ O₂ ) to inducing EPCs injury. At 24 hrs after the H₂ O₂ treatment, cell viability, the uptake capacity on DiI-Ac-LDL, and carrying ability on FITC-UEA-l and multiplication capacity were analyzed. The mechanism process was carefully researched by valued the characteristics of the mitochondrion morphology, membrane potential, ATP levels, and the expressing of apoptosis pathways. Small RNA sequencing indicated that the expression level of miR-324-5p in peripheral blood EPCs of patients with STEMI was significantly lower compared with the healthy volunteers. The Mtfr1 has been confirmed as a targeted gene of miR-324-5p through miRTarBase software and western blot. The miR-324-5p mimic units could be contributed for the improvement of viability, the uptake capacity on DiI-Ac-LDL and carrying ability on FITC-UEA-l and multiplication capacity on oxidative stress-injured EPCs. miR-324-5p could suppress mitochondrial fragmentation, promote membrane potential, and ATP levels, as well as protect against oxidative stress-induced EPCs apoptosis. Our results suggested that miR-324-5p protects against oxidative stress-induced EPCs injury by regulating Mtfr1.

Endothelial Cell Metabolism

Endothelial cells (ECs) are more than inert blood vessel lining material. Instead, they are active players in the formation of new blood vessels (angiogenesis) both in health and (life-threatening) diseases. Recently, a new concept arose by which EC metabolism drives angiogenesis in parallel to well-established angiogenic growth factors (e.g., vascular endothelial growth factor). 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3-driven glycolysis generates energy to sustain competitive behavior of the ECs at the tip of a growing vessel sprout, whereas carnitine palmitoyltransferase 1a-controlled fatty acid oxidation regulates nucleotide synthesis and proliferation of ECs in the stalk of the sprout. To maintain vascular homeostasis, ECs rely on an intricate metabolic wiring characterized by intracellular compartmentalization, use metabolites for epigenetic regulation of EC subtype differentiation, crosstalk through metabolite release with other cell types, and exhibit EC subtype-specific metabolic traits. Importantly, maladaptation of EC metabolism contributes to vascular disorders, through EC dysfunction or excess angiogenesis, and presents new opportunities for anti-angiogenic strategies. Here we provide a comprehensive overview of established as well as newly uncovered aspects of EC metabolism.

Constitutive Expression of Adiponectin in Endothelial Progenitor Cells Protects a Rat Model of Cerebral Ischemia

Endothelial progenitor cells (EPCs), as precursors to endothelial cells, play a significant part in the process of endogenous blood vessel repair and maintenance of endothelial integrity. Adiponectin (APN) is an adipocyte-specific adipocytokine. In this study, we aim to test whether we transplant a combined graft of EPCs transfected with the adiponectin gene into a rat model of cerebral ischemia could improve functional recovery after middle cerebral artery occlusion (MCAO). Sprague-Dawley (SD) rats were randomly divided into a MCAO control group, a MCAO EPC treatment group, and a MCAO LV-APN-EPC treatment group. A focal cerebral ischemia and reperfusion model was induced by the intraluminal suture method. After 2 h of reperfusion, EPCs were transplanted by injection through the tail vein. A rotarod test was conducted to assess behavioral function before MCAO and on days 1, 7, and 14 after MCAO. After 14 d, TTC staining, CD31 immunofluorescence, and TUNEL staining were used to evaluate infarct volume, microvessel density, and cell apoptosis. Results revealed that behavioral function, infarct area percentage, microvessel density, and cell apoptosis rates were more favorable in the LV-APN-EPC treatment group than in the EPC treatment group. These data suggested that gene-modified cell therapy may be a useful approach for the treatment of ischemic stroke.

Estrogen-mediated hemangioma-derived stem cells through estrogen receptor-α for infantile hemangioma

Background

Infantile hemangiomas (IHs) are the most common benign vascular tumor of infancy. They occur more frequently in female infants. The cause of hemangioma is currently unknown; however, current studies suggested the importance of estrogen (E2) signaling in hemangioma proliferation.

Methods

Hemangioma-derived stem cells (HemSCs) were cultured with estrogen for 48–72 h; the cell viability and proliferation were evaluated with the messenger RNA (mRNA) and protein expression levels of fibroblast growth factor 2 (FGF2), vascular endothelial growth factor-A (VEGF-A) and estrogen receptor-α (ER-α), by application of several in vitro assays, such as methyl thiazolyl tetrazolium (MTT), reverse transcriptase–polymerase chain reaction (RT-PCR), real-time PCR, enzyme-linked immunosorbent assay (ELISA) and Western blotting. Also, the cell population’s response to external estrogen was investigated by in vivo experiments. HemSCs and human umbilical vein endothelial cells (HUVECs) were mixed and injected subcutaneously into 20 flank of BALB/c-nu mice, which were randomly divided into 5 groups based on different E2 treatment doses (0, 0.01, 0.1 and 1 mg, respectively), 0.1 mg dimethyl sulfoxide (DMSO) as control. Each group of mice were treated intramuscularly every week, then 2 and 4 weeks later, the subcutaneous implants were harvested and evaluated the tumor tissues with microvessel density (MVD) assay and immunohistochemistry.

Results

The study demonstrated that application of E2 increased the expression of FGF2, VEGF-A, and ER-α in HemSCs with the optimal concentration from 10⁻⁹ to 10⁻⁵ M. Two-week treatment of E2 promoted expression of VEGF-A and FGF2 in HemSCs culture. Morphological, histological and immunohistological improvements were observed in vivo using murine IH model in which HemSCs and HUVECs were implanted into BALB/c-nu mice that were post-injected with E2. In the grafts, mean MVD was markedly increased.

Conclusion

The results suggested that E2 promotes angiogenesis via combination with ER-α to up-regulate the expression of VEGF-A in HemSCs, promoting proliferation of IHs. These findings provide critical insight into the potential mechanisms of E2 action on IHs.

HMGB1 induces endothelial progenitor cells apoptosis via RAGE-dependent PERK/eIF2α pathway

Studies have demonstrated that the high-mobility group 1B protein (HMGB1) could regulate endothelial progenitor cell (EPC) homing, but the effect of HMGB1 on EPC apoptosis and associated mechanisms are still unclear. The aim of this study was to investigate the effects of HMGB1 on EPC apoptosis and the possible involvement of the endoplasmic reticulum (ER) stress pathway. EPC apoptosis was determined by flow cytometry. The expressions of PERK, eIF2α, and CHOP were detected by western blotting. Additionally, the effects of PERK shRNA on the biological behaviors of EPCs were assessed. Our results showed that incubation of EPCs with HMGB1 (0.1-1 μg/ml) for 12-48 h induced apoptosis as well as activated ER stress transducers, as assessed by up-regulating PERK protein expression and eIF2α phosphorylation in a dose or time-dependent manner. Moreover, HMGB1-mediated EPC apoptosis and CHOP expression were dramatically suppressed by PERK shRNA or a specific eIF2α inhibitor (salubrinal). Importantly, a blocking antibody specifically targeted against RAGE (anti-RAGE antibody) markedly inhibited HMGB1-induced EPC apoptosis and ER stress marker protein (PERK, eIF2α, and CHOP) expression levels. Our novel findings suggest that HMGB1 triggered EPC apoptosis in a manner of RAGE-mediated activation of the PERK/eIF2α pathway.

Progenitor Cells for Arterial Repair: Incremental Advancements towards Therapeutic Reality

Coronary revascularization remains the standard treatment for obstructive coronary artery disease and can be accomplished by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery. Considerable advances have rendered PCI the most common form of revascularization and improved clinical outcomes. However, numerous challenges to modern PCI remain, namely, in-stent restenosis and stent thrombosis, underscoring the importance of understanding the vessel wall response to injury to identify targets for intervention. Among recent promising discoveries, endothelial progenitor cells (EPCs) have garnered considerable interest given an increasing appreciation of their role in vascular homeostasis and their ability to promote vascular repair after stent placement. Circulating EPC numbers have been inversely correlated with cardiovascular risk, while administration of EPCs in humans has demonstrated improved clinical outcomes. Despite these encouraging results, however, advancing EPCs as a therapeutic modality has been hampered by a fundamental roadblock: what constitutes an EPC? We review current definitions and sources of EPCs as well as the proposed mechanisms of EPC-mediated vascular repair. Additionally, we discuss the current state of EPCs as therapeutic agents, focusing on endogenous augmentation and transplantation.

Mesenchymal Stem Cells Combined with Hepatocyte Growth Factor Therapy for Attenuating Ischaemic Myocardial Fibrosis: Assessment using Multimodal Molecular Imaging

Clinically, myocardial fibrosis is increasingly being recognized as a new therapeutic target for ischaemic heart diseases. The aim of this study was to investigate whether noninvasive multimodal molecular imaging could be used to dynamically assess whether the combination of bone marrow mesenchymal stem cells (BMSCs) and hepatocyte growth factor (HGF) therapy can synergistically attenuate myocardial fibrosis after myocardial infarction (MI). MI was induced in 28 rats by coronary ligation with subsequent injection of BMSCs/HGF, BMSCs, HGF, or saline into the border zone under echocardiography guidance. The therapeutic procedure and treatment effects were tracked and assessed using bioluminescence imaging (BLI) and cardiac magnetic resonance (MR) imaging. Four weeks after transplantation therapy, cardiac MR imaging demonstrated that BMSC/HGF-treated animals showed better ejection fractions (p < 0.001) and smaller scar sizes (p < 0.001) than those treated with BMSCs or HGF alone. Histopathological and immunohistochemical results showed less collagen deposition, increased microvessel densities and more regenerative cardiomyocytes in the BMSC/HGF-treated animals than in those receiving HGF or BMSCs alone (all p < 0.05). Multimodal molecular imaging allows a specific and timely strategy to be established for dynamically tracking treatment and noninvasively assessing the therapeutic effects. Under echocardiography guidance, intramyocardial injection of transfected HGF with BMSCs can enhance cell survival, improve cardiac function, stimulate angiogenesis, and reduce myocardial fibrosis in a post-MI rat model.

CXCR7/p-ERK-Signaling Is a Novel Target for Therapeutic Vasculogenesis in Patients with Coronary Artery Disease

Coronary artery disease (CAD) is characterized by insufficient vasculogenic response to ischemia, which is typically accompanied by dysfunction of endothelial outgrowth cells (EOCs). CXC chemokine receptor 7 (CXCR7) is a key modulator of the neovascularization of EOCs to perfusion defect area. However, the mechanism underlying the role of EOCs in CAD-related abnormal vasculogenesis is still not clear. Here, we investigated the alteration of EOCs-related vasculogenic capacity in patients with CAD and its potential mechanism. Compared with EOCs isolated from healthy subjects, EOCs from CAD patients showed an impaired vasculogenic function in vitro. CXCR7 expression of EOCs from CAD patients was downregulated. Meanwhile, the phosphorylation of extracellular signal-regulated kinase (ERK), downstream of CXCR7 signaling, was also reduced. CXCR7 expression introduced by adenovirus increased the phosphorylation of ERK, which was parallel to improved function of EOCs. The enhanced adhesion and vasculogenesis of EOCs can be blocked by short interfering RNA (siRNA) against CXCR7 and ERK inhibitor PD098059. Therefore, our study demonstrates that the upregulation of CXCR7 signaling contributes to increased vasculogenic capacity of EOCs from CAD patients, indicating that CXCR7 signaling may be a novel therapeutic vasculogenic target for CAD.

Scaffolds and Cell-Based Tissue Engineering for Blood Vessel Therapy

The increasing morbidity of cardiovascular diseases in modern society has made it crucial to develop a small-caliber blood vessel. In the absence of appropriate autologous vascular grafts, an alternative prosthesis must be constructed for cardiovascular disease patients. The aim of this article is to describe the advances in making cell-seeded cardiovascular prostheses. It also discusses the combinations of types of scaffolds and cells, especially autologous stem cells, which are suitable for application in tissue-engineered vessels with the favorable properties of mechanical strength, antithrombogenicity, biocompliance, anti-inflammation, fatigue resistance and long-term durability. This article highlights the advancements in cellular tissue-engineered vessels in recent years.

Development of a Tissue-Engineered Bypass Graft Seeded with Stem Cells

The gold standard conduit for bypass of diseased small-diameter arteries remains autologous vascular tissue. In the absence of such tissue, patients are offered bypass with prosthetic material, with far less durable results. Vascular tissue engineering, the creation of a vascular conduit by seeding a tubular scaffold with various cells, may offer an alternative approach to this difficult situation. Herein we review some of the significant challenges that remain in designing an ideal vascular conduit and outline potential solutions offered by a graft created by seeding natural vascular tissue (decellularized vein allograft) with readily available autologous cells (adipose-derived stem cells).

Emerging Concepts in Paracrine Mechanisms in Regenerative Cardiovascular Medicine and Biology

In the past decade, substantial evidence supports the paradigm that stem cells exert their reparative and regenerative effects, in large part, through the release of biologically active molecules acting in a paracrine fashion on resident cells. The data suggest the existence of a tissue microenvironment where stem cell factors influence cell survival, inflammation, angiogenesis, repair, and regeneration in a temporal and spatial manner.

Aliskiren directly improves endothelial progenitor cell function from Type II diabetic patients

BACKGROUND

Endothelial progenitor cell (EPC) functions are impaired in the presence of diabetes mellitus. Aliskiren is a direct renin inhibitor, which is expected to modify proangiogenic cells. This study aimed to investigate whether and how aliskiren could improve the function of EPCs from patients with type II diabetes (T2DM).

MATERIALS AND METHODS

Endothelial progenitor cells fibronectin adhesion assay, chamber assay and in vitro tube formation assay were used to estimate the degree of EPC adhesion, migration and tube formation abilities. EPC protein and mRNA expressions were evaluated by Western blot and quantitative RT-PCR, respectively. EPC vascular endothelial growth factor (VEGF) and (pro)renin receptor ((P)RR) expression was knocked down by VEGF and (P)RR siRNA.

RESULTS

Aliskiren (0·1 or 10 μM) dose-dependently improved functions and increased both VEGF and stromal cell-derived factor-1α (SDF-1α) expression of EPCs from patients with T2DM or EPCs from healthy volunteers and treated with high glucose. Transfection with VEGF siRNA significantly reduced the aliskiren-induced SDF-1α expression. Furthermore, (P)RR siRNA transfection impaired the aliskiren-induced VEGF and SDF-1 expression.

CONCLUSIONS

The results show that aliskiren improved EPC function from patients with T2DM in a dose-dependent manner probably via the (P)RR and VEGF/SDF-1α-related mechanisms.

Endothelial progenitor cells (EPCs) in ageing and age-related diseases: How currently available treatment modalities affect EPC biology, atherosclerosis, and cardiovascular outcomes

Endothelial progenitor cells (EPCs) are mononuclear cells that circulate in the blood and are derived from different tissues, expressing cell surface markers that are similar to mature endothelial cells. The discovery of EPCs has lead to new insights in vascular repair and atherosclerosis and also a new theory for ageing. EPCs from the bone marrow and some other organs aid in vascular repair by migrating to distant vessels where they differentiate into mature endothelial cells and replace old and injured endothelial cells. The ability of EPCs to repair vascular damage depends on their number and functionality. Currently marketed drugs used in a variety of diseases can modulate these characteristics. In this review, the effect of currently available treatment options for cardiovascular and metabolic disorders on EPC biology will be discussed. The various EPC-based therapies that will be discussed include lipid-lowering agents, antihypertensive agents, antidiabetic drugs, phosphodiesteraze inhibitors, hormones, as well as EPC capturing stents.

Icaritin Inhibits Collagen Degradation-Related Factors and Facilitates Collagen Accumulation in Atherosclerotic Lesions: A Potential Action for Plaque Stabilization

Most acute coronary syndromes result from rupture of vulnerable atherosclerotic plaques. The collagen content of plaques may critically affect plaque stability. This study tested whether Icaritin (ICT), an intestinal metabolite of Epimedium-derived flavonoids, could alter the collagen synthesis/degradation balance in atherosclerotic lesions. Rabbits were fed with an atherogenic diet for four months. Oral administration of ICT (10 mg·kg(-1)·day(-1)) was started after two months of an atherogenic diet and lasted for two months. The collagen degradation-related parameters, including macrophages accumulation, content and activity of interstitial collagenase-1 (MMP-1), and the collagen synthesis-related parameters, including amount and distribution of smooth muscle cells (SMC) and collagen mRNA/protein levels, were evaluated in the aorta. ICT reduced plasma lipid levels, inhibited macrophage accumulation, lowered MMP-1 mRNA and protein expression, and suppressed proteolytic activity of pro-MMP-1 and MMP-1 in the aorta. ICT changed the distribution of the SMCs towards the fibrous cap of lesions without increasing the amount of SMCs. Higher collagen protein content in lesions and aorta homogenates was observed with ICT treatment compared with the atherogenic diet only, without altered collagen mRNA level. These results suggest that ICT could inhibit the collagen degradation-related factors and facilitate collagen accumulation in atherosclerotic lesions, indicating a new potential of ICT in atherosclerotic plaques.

Concise review: tissue-specific microvascular endothelial cells derived from human pluripotent stem cells

Accumulating evidence suggests that endothelial cells (ECs) display significant heterogeneity across tissue types, playing an important role in tissue regeneration and homeostasis. Recent work demonstrating the derivation of tissue-specific microvascular endothelial cells (TS-MVECs) from human pluripotent stem cells (hPSCs) has ignited the potential to generate tissue-specific models which may be applied to regenerative medicine and in vitro modeling applications. Here, we review techniques by which hPSC-derived TS-MVECs have been made to date and discuss how current hPSC-EC differentiation protocols may be directed toward tissue-specific fates. We begin by discussing the nature of EC tissue specificity in vivo and review general hPSC-EC differentiation protocols generated over the last decade. Finally, we describe how specificity can be integrated into hPSC-EC protocols to generate hPSC-derived TS-MVECs in vitro, including EC and parenchymal cell coculture, directed differentiation, and direct reprogramming strategies.

Endothelial Progenitor Cells Predict Cardiovascular Events after Atherothrombotic Stroke and Acute Myocardial Infarction. A PROCELL Substudy

Introduction

The aim of this study was to determine prognostic factors for the risk of new vascular events during the first 6 months after acute myocardial infarction (AMI) or atherothrombotic stroke (AS). We were interested in the prognostic role of endothelial progenitor cells (EPC) and circulating endothelial cells (CEC)

Methods

Between February 2009 and July 2012, 100 AMI and 50 AS patients were consecutively studied in three Spanish centres. Patients with previously documented coronary artery disease or ischemic strokes were excluded. Samples were collected within 24h of onset of symptoms. EPC and CEC were studied using flow cytometry and categorized by quartiles. Patients were followed for up to 6 months. NVE was defined as new acute coronary syndrome, transient ischemic attack (TIA), stroke, or any hospitalization or death from cardiovascular causes. The variables included in the analysis included: vascular risk factors, carotid intima-media thickness (IMT), atherosclerotic burden and basal EPC and CEC count. Multivariate survival analysis was performed using Cox regression analysis.

Results

During follow-up, 19 patients (12.66%) had a new vascular event (5 strokes; 3 TIAs; 4 AMI; 6 hospitalizations; 1 death). Vascular events were associated with age (P = 0.039), carotid IMT≥0.9 (P = 0.044), and EPC count (P = 0.041) in the univariate analysis. Multivariate Cox regression analysis showed an independent association with EPC in the lowest quartile (HR: 10.33, 95%CI (1.22–87.34), P = 0.032] and IMT≥0.9 [HR: 4.12, 95%CI (1.21–13.95), P = 0.023].

Conclusions

Basal EPC and IMT≥0.9 can predict future vascular events in patients with AMI and AS, but CEC count does not affect cardiovascular risk.

Icariin regulates PRMT/ADMA/DDAH pathway to improve endothelial function

BACKGROUND

Oxidative stress may affect PRMT/ADMA/DDAH (protein arginine methyltransferases/asymmetric dimethylarginine/dimethylarginine dimethylaminohydrolase) pathway to impair endothelial dysfunction. The present study was carried out to test the effect of icariin on endothelial function and the mechanisms responsible for this.

METHODS

Eighty mice at 12 weeks of age were separated randomly into four groups (n = 20): C57BL/6J control, untreated apolipoprotein E-deficient (ApoE(-/-)), two groups of icariin-treated (10 or 30 mg/kg body wt/day, intragastrically) ApoE(-/-). Primary human umbilical vein endothelial cells (HUVECs) were randomly divided into 7 groups: control group, vehicle of icariin (10 μmol/L) group, icariin (10 μmol/L) group, lysophosphatidylcholine (LPC) (10 μg/mL) group, LPC plus icariin (1 μmol/L) group, LPC plus icariin (3 μmol/L) group, and LPC plus icariin (10 μmol/L) group.

RESULTS

In ApoE(-/-) mice and primary HUVECs, icariin treatment decreased reactive oxygen species production, PRMT I expression, ADMA level, half-maximum effective concentration of ApoE(-/-) mice aortic rings. Icariin increased DDAH II expression, DDAH activity, maximal relaxation value and endothelium-dependent vasorelaxation in aortic rings from ApoE(-/-) mice (p < 0.05 or p < 0.01).

CONCLUSIONS

The present results suggest that icariin regulates PRMT/ADMA/DDAH pathway to improve endothelial function.

Longer-term outcomes of darbepoetin alfa versus epoetin alfa in patients with ESRD initiating hemodialysis: a quasi-experimental cohort study

BACKGROUND

Adequately powered studies directly comparing hard clinical outcomes of darbepoetin alfa (DPO) versus epoetin alfa (EPO) in patients undergoing dialysis are lacking.

STUDY DESIGN

Observational, registry-based, retrospective cohort study; we mimicked a cluster-randomized trial by comparing mortality and cardiovascular events in US patients initiating hemodialysis therapy in facilities (almost) exclusively using DPO versus EPO.

SETTING & PARTICIPANTS

Nonchain US hemodialysis facilities; each facility switching from EPO to DPO (2003-2010) was matched for location, profit status, and facility type with one EPO facility. Patients subsequently initiating hemodialysis therapy in these facilities were assigned their facility-level exposure.

INTERVENTION

DPO versus EPO.

OUTCOMES

All-cause mortality, cardiovascular mortality; composite of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal stroke.

MEASUREMENTS

Unadjusted and adjusted HRs from Cox proportional hazards regression models.

RESULTS

Of 508 dialysis facilities that switched to DPO, 492 were matched with a similar EPO facility; 19,932 (DPO: 9,465 [47.5%]; EPO: 10,467 [52.5%]) incident hemodialysis patients were followed up for 21,918 person-years during which 5,550 deaths occurred. Almost all baseline characteristics were tightly balanced. The demographics-adjusted mortality HR for DPO (vs EPO) was 1.06 (95% CI, 1.00-1.13) and was materially unchanged after adjustment for all other baseline characteristics (HR, 1.05; 95% CI, 0.99-1.12). Cardiovascular mortality did not differ between groups (HR, 1.05; 95% CI, 0.94-1.16). Nonfatal outcomes were evaluated among 9,455 patients with fee-for-service Medicare: 4,542 (48.0%) in DPO and 4,913 (52.0%) in EPO facilities. During 10,457 and 10,363 person-years, 248 and 372 events were recorded, respectively, for strokes and MIs. We found no differences in adjusted stroke or MI rates or their composite with cardiovascular death (HR, 1.10; 95% CI, 0.96-1.25).

LIMITATIONS

Nonrandom treatment assignment, potential residual confounding.

CONCLUSIONS

In incident hemodialysis patients, mortality and cardiovascular event rates did not differ between patients treated at facilities predominantly using DPO versus EPO.

Administration of erythropoietin in patients with myocardial infarction: does it make sense? An updated and comprehensive meta-analysis and systematic review

This systematic review with meta-analysis sought to determine protective effects of erythropoietin on clinical outcomes following percutaneous coronary intervention (PCI). Medline, Embase, Elsevier and Sciences online database as well as Google scholar literature were used for selecting appropriate studies with randomized controlled design. The effect sizes measured were odds ratio (OR) for categorical variables and weighted mean difference (WMD) with 95% confidence interval for calculating differences between mean values of duration of hospitalization in intervention and control groups. Values of P<0.1 for Q test or I(2)>50% indicated significant heterogeneity between the studies. The literature searches of all major databases retrieved 973 studies. After screening, a total of 15 trials that reported outcomes were identified. Pooled analysis was performed on left ventricular ejection fraction (WMD of -0.047; 95% CI: -0.912 to 0.819; P=0.9), left ventricular end diastolic volume (WMD of -0.363; 95% CI: -3.902 to 3.175; P=0.8), left ventricular end systolic volume (WMD of 0.346; 95% CI: -2.533 to 3.226; P=0.8), infarct size (WMD of -0.446; 95% CI: -2.352 to -1.460; P=0.6), stroke (OR of 2.1; 95% CI: 0.58 to 7.54; P=0.2), re-myocardial infarction (OR of 1.06; 95% CI: 0.52 to 2.185; P=0.8), heart failure (OR of 0.53; 95% CI: 0.259 to 1.105; P=0.09), mortality (OR of 0.56; 95% CI: 0.27 to 1.19; P=0.13), thrombosis (OR of 0.774; 95% CI: 0.41 to 1.45; P=0.4), major adverse cardiovascular events (OR of 0.926; 95% CI: 0.63 to 1.35; P=0.6). Short-term administration of EPO in patients with myocardial infarction (MI) undergoing PCI does not result in improvement in cardiac function, reduction of infarct size and all-cause mortality. Low dose EPO therapy may not be the choice of treatment for the patients with MI, while higher doses might be more effective.

Mortality risk of darbepoetin alfa versus epoetin alfa in patients with CKD: systematic review and meta-analysis

BACKGROUND

Epoetin alfa (EPO) and darbepoetin alfa (DPO) are erythropoiesis-stimulating agents that are widely and interchangeably used for the treatment of anemia in patients with advanced chronic kidney disease and end-stage renal disease. No study has specifically compared the risks of hard study outcomes between EPO and DPO, including mortality.

STUDY DESIGN

Systematic review of the literature and meta-analysis.

SETTING & POPULATION

Patients enrolled in randomized trials comparing EPO versus DPO for the treatment of anemia in adults with chronic kidney disease, including those requiring dialysis.

SELECTION CRITERIA FOR STUDIES

We conducted a systematic search of the literature (PubMed, CENTRAL, SCOPUS, and EMBASE, all years) and industry resources, using predefined search terms and data abstraction tools. We then summarized key characteristics and findings of these trials and performed a random-effects meta-analysis of trials with at least 3 months' duration to identify the summary OR of mortality between patients randomly assigned to DPO versus EPO.

INTERVENTION

DPO versus EPO.

OUTCOME

All-cause mortality.

RESULTS

We identified 9 trials that met the stated inclusion criteria. Overall, 2,024 patients were included in the meta-analysis, of whom 126 died during follow-up, which ranged from 20 to 52 weeks. We found no significant difference in mortality between patients randomly assigned to DPO versus EPO (OR, 1.33; 95% CI, 0.88-2.01). No treatment heterogeneity across studies was detected (Q statistic=4.60; P=0.8).

LIMITATIONS

Generalizability to nontrial populations is uncertain.

CONCLUSIONS

Few trials directly comparing DPO and EPO have been conducted and follow-up was limited. In aggregate, no effect of specific erythropoiesis-stimulating agent on mortality was identified, but the confidence limits were wide and remained compatible with considerable harm from DPO. Absent adequately powered randomized trials, observational postmarketing comparative effectiveness studies comparing these erythropoiesis-stimulating agents are required to better characterize the long-term safety profiles of these agents.

Fundamentals and application of magnetic particles in cell isolation and enrichment: a review

Magnetic sorting using magnetic beads has become a routine methodology for the separation of key cell populations from biological suspensions. Due to the inherent ability of magnets to provide forces at a distance, magnetic cell manipulation is now a standardized process step in numerous processes in tissue engineering, medicine, and in fundamental biological research. Herein we review the current status of magnetic particles to enable isolation and separation of cells, with a strong focus on the fundamental governing physical phenomena, properties and syntheses of magnetic particles and on current applications of magnet-based cell separation in laboratory and clinical settings. We highlight the contribution of cell separation to biomedical research and medicine and detail modern cell-separation methods (both magnetic and non-magnetic). In addition to a review of the current state-of-the-art in magnet-based cell sorting, we discuss current challenges and available opportunities for further research, development and commercialization of magnetic particle-based cell-separation systems.

Diabetes, Endothelial Dysfunction, and Vascular Repair: What Should a Diabetologist Keep His Eye on?

Cardiovascular complications are the most common complications of diabetes mellitus. A prominent attribute of diabetic cardiovascular complications is accelerated atherosclerosis, considered as a still incurable disease, at least at more advanced stages. The discovery of endothelial progenitor cells (EPCs), able to replace old and injured mature endothelial cells and capable of differentiating into healthy and functional endothelial cells, has offered the prospect of merging the traditional theories on the pathogenesis of atherosclerosis with evolving concepts of vascular biology. The literature supports the notion that EPC alterations are involved in the pathogenesis of vascular diseases in diabetics, but at present many questions remain unanswered. In this review the aspects linking endothelial progenitor cells to the altered vascular biology in diabetes mellitus are discussed.

Molecular pathways of arterial aging

The incidence of stroke and myocardial infarction increases in aged patients and it is associated with an adverse outcome. Considering the aging population and the increasing incidence of cardiovascular disease, the prediction for population well-being and health economics is daunting. Accordingly, there is an unmet need to focus on fundamental processes underlying vascular aging. A better understanding of the pathways leading to arterial aging may contribute to design mechanism-based therapeutic approaches to prevent or attenuate features of vascular senescence. In the present review, we discuss advances in the pathophysiology of age-related vascular dysfunction including nitric oxide signalling, dysregulation of oxidant/inflammatory genes, epigenetic modifications and mechanisms of vascular calcification as well as insights into vascular repair. Such an overview highlights attractive molecular targets for the prevention of age-driven vascular disease.

Hydroxybutyl Chitosan Polymer-Mediated CD133 Antibody Coating of Metallic Stents to Reduce Restenosis in a Porcine Model of Atherosclerosis

Antibody-coated stents to capture circulating endothelial progenitor cells (EPCs) for re-endothelialization appear to be a novel therapeutic option for the treatment of atherosclerotic disease. Hydroxybutyl chitosan (HBC), a linear polysaccharide made from shrimps and other crustacean shells, is biocompatible, nontoxic, and hydrophilic, making it ideal for biomedical applications. In this study, HBC was explored for the immobilization of anti-CD133 antibodies. We demonstrated that CD133 antibodies mediated by HBC were successfully coated on cobalt-chromium alloy discs and metal stents. The coating was homogeneous and smooth as shown by electronic microscopy analysis. Balloon expansion of coated stents did not cause cracking or peeling. The HBC discs promoted CD133+ EPCs and human umbilical vein endothelial cell growth in vitro. The CD133 antibody-coated but not bare discs bound CD133+ EPCs in vitro. Implantation of CD133 antibody-coated stents significantly inhibited intimal hyperplasia and reduced restenosis compared with implantation of bare stents in a porcine model of atherosclerosis. These findings suggest HBC is a valuable anchoring agent that can be applied for bioactive coating of stents and that CD133 antibody-coated stents might be a potential therapeutic alternative for the treatment of atherosclerotic disease.

N-Acetylcysteine Ameliorates Experimental Autoimmune Myocarditis in Rats via Nitric Oxide

BACKGROUND

Oxidative stress may play an important role in the development of myocarditis. We investigated the effects of N-acetylcysteine (NAC), a potent antioxidant, on experimental autoimmune myocarditis (EAM) in rats.

METHODS AND RESULTS

A rat model of porcine myosin-induced EAM was used. After the immunization with myosin, NAC (20 mg/kg/d) or saline was injected intraperitoneally on days 1 to 21. Additional myosin-immunized rats treated with NAC were orally given 25 mg/kg/d of N(G)-nitro-l-arginine methylester (l-NAME), an inhibitor of nitric oxide (NO) synthase, and N(G)-nitro-d-arginine methylester (d-NAME), an inactive enantiomer. The NAC treatment improved cardiac pathology associated with reduced superoxide production. In the EAM rats treated with NAC associated with oral l-NAME, but not with oral d-NAME, the severity of myocarditis was not reduced. Expression of intercellular adhesion molecule 1 was reduced by NAC treatment. Myocardial c-kit(+) cells were demonstrated only in the NAC-treated group. Hemodynamic study showed that the increased left ventricular mass produced by myocardial inflammation tended to be reduced by NAC treatment.

CONCLUSION

Treatment with NAC ameliorated myocardial injury via NO system in a rat model of myocarditis.

Endothelial progenitor cells in cardiovascular diseases

Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells (EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vasculogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk factors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardiovascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evaluate the challenges facing EPC research and how these may be overcome.

Study of bilineage differentiation of human-bone-marrow-derived mesenchymal stem cells in oxidized sodium alginate/N-succinyl chitosan hydrogels and synergistic effects of RGD modification and low-intensity pulsed ultrasound

The level of formation of new bone and vascularization in bone tissue engineering scaffold implants is considered as a critical factor for clinical application. In this study, an approach using an RGD-grafted oxidized sodium alginate/N-succinyl chitosan (RGD-OSA/NSC) hydrogel as a scaffold and low-intensity pulsed ultrasound (LIPUS) as mechanical stimulation was proposed to achieve a high level of formation of new bone and vascularization. An in vitro study of endothelial and osteogenic differentiations of human-bone-marrow-derived mesenchymal stem cells (hMSCs) was conducted to evaluate it. The results showed that RGD-OSA/NSC composite hydrogels presented good biological properties in attachment, proliferation and differentiation of cells. The MTT cell viability assay showed that the total number of cells increased more significantly in the LIPUS-stimulated groups with RGD than that in the control ones; similar results were obtained for alkaline phosphatase activity/staining and mineralized nodule formation assay of osteogenic induction and immunohistochemical test of endothelial induction. The positive synergistic effect of LIPUS and RGD on the enhancement of proliferation and differentiation of hMSCs was observed. These findings suggest that the hybrid use of RGD modification and LIPUS might provide one approach to achieve a high level of formation of new bone and vascularization in bone tissue engineering scaffold implants.

Effects of physical activity on endothelial progenitor cells (EPCs)

Physical activity has a therapeutic role in cardiovascular disease (CVD), through its beneficial effects on endothelial function and cardiovascular system. Circulating endothelial progenitor cells (EPCs) are bone marrow (BM) derived cells that represent a novel therapeutic target in CVD patients, because of their ability to home to sites of ischemic injury and repair the damaged vessels. Several studies show that physical activity results in a significant increase in circulating EPCs, and, in particular, there are some evidence of the beneficial exercise-induced effects on EPCs activity in CVD settings, including coronary artery disease (CAD), heart failure (HF), and peripheral artery disease (PAD). The aim of this paper is to review the current evidence about the beneficial effects of physical exercise on endothelial function and EPCs levels and activity in both healthy subjects and patients with CVD.

Regulation of smooth muscle cells in development and vascular disease: current therapeutic strategies

Vascular smooth muscle cells (SMCs) exhibit extensive phenotypic diversity and rapid growth during embryonic development, but maintain a quiescent, differentiated state in adult. The pathogenesis of vascular proliferative diseases involves the proliferation and migration of medial vascular SMCs into the vessel intima, possibly reinstating their embryonic gene expression programs. Multiple mitogenic stimuli induce vascular SMC proliferation through cell cycle progression. Therapeutic strategies targeting cell cycle progression and mitogenic stimuli have been developed and evaluated in animal models of atherosclerosis and vascular injury, and several clinical studies. Recent discoveries on the recruitment of vascular progenitor cells to the sites of vascular injury suggest new therapeutic potentials of progenitor cell-based therapies to accelerate re-endothelialization and prevent engraftment of SMC-lineage progenitor cells. Owing to the complex and multifactorial nature of SMC regulation, combinatorial antiproliferative approaches are likely to be used in the future in order to achieve maximal efficacy and reduce toxicity.

Old World hantaviruses: aspects of pathogenesis and clinical course of acute renal failure

Hantavirus-associated diseases represent emerging infections that are ranked in the highest priority group of communicable diseases for surveillance and epidemiological research. In the last years, several novel hantavirus species were described and the number of host reservoir species harboring hantaviruses is also increasing. Reports of cases with severe or atypical clinical courses become also more frequent. These facts raise more and more questions concerning host reservoir specificity, pathogenicity and molecular mechanism of pathogenesis. Hantavirus disease is characterized by vascular leakage due to increased capillary permeability. The infection manifests often in the lung (hantaviral cardiopulmonary syndrome; HCPS) or in the kidney (hemorrhagic fever with renal syndrome, HFRS). The underlying mechanisms of both syndromes are probably similar despite the difference in organ tropism. Characterization of hantaviral replication cycle and of patient-specific determinants will help to identify factors responsible for the clinical symptoms and course.

Long-term Angiogenesis Efficacy Using a Heparin-Conjugated Fibrin (HCF) Delivery System with HBM-MSCs

BACKGROUND AND OBJECTIVES

Heparin-conjugated fibrin (HCF) is suitable for the release and localization of bFGF. We analyzed the effects of a bFGF delivery system using HCF with human bone marrow-derived mesenchymal stem cells (HBM- MSCs) in a dog ischemic limb model.

METHODS AND RESULTS

Animals were divided into HBM-MSCs, HBM-MSCs＋HCF, bFGF-HCF, and HBM-MSCs＋ bFGF-HCF groups. A total of 1×10(7) HBM-MSCs were injected per animal, and the amount of bFGF was 1 mg per dog. Ischemic muscles were harvested at eight weeks and six months after injection of cells. The HBM-MSCs＋ bFGF-HCF group exhibited decreased proportions of capillaries and arterioles six months after transplantation. However, there were more cells positive for the angiogenic factors, VEGF and PDGF, in the eight-week specimens compared with those harvested six months after transplantation.

CONCLUSIONS

Our results demonstrated that a single injection of HBM-MSCs did not have significant long-term angiogenic effects; however, a bFGF delivery system using HCF exerted prolonged angiogenic effects when combined with HBM-MSCs.

Mobilization of circulating endothelial progenitor cells correlates with the clinical course of hantavirus disease

Infections with hemorrhagic fever viruses are characterized by increased permeability leading to capillary leakage. Hantavirus infection is associated with endothelial dysfunction, and the clinical course is related to the degree of vascular injury. Circulating endothelial progenitor cells (cEPCs) play a pivotal role in the repair of the damaged endothelium. Therefore, we analyzed the number of cEPCs and their mobilizing growth factors in patients suffering from hantavirus disease induced by infection with Puumala virus. The numbers of EPCs of 36 hantavirus-infected patients and age- and gender-matched healthy controls were analyzed by flow cytometry. Concentrations of cEPC-mobilizing growth factors in plasma were determined by enzyme-linked immunosorbent assay. Laboratory parameters were correlated with the number of cEPCs. In patients infected with hantavirus, the number of cEPCs was significantly higher than that in healthy controls. Levels of mobilizing cytokines were upregulated in patients, and the mobilization of cEPCs is paralleled with the normalization of clinical parameters. Moreover, higher levels of cEPCs correlated with higher serum albumin levels and platelet concentrations. Our data indicate that cEPCs may play a role in the repair of hantavirus-induced endothelial damage, thereby influencing the clinical course and the severity of symptoms.

Lacidipine improves endothelial repair capacity of endothelial progenitor cells from patients with essential hypertension

BACKGROUND

Endothelial progenitor cells (EPCs) play a critical role in maintaining the integrity of vascular endothelium following arterial injury. Lacidipine has a beneficial effect on endothelium of hypertensive patients, but limited data are available on EPCs-mediated endothelial protection. This study tests the hypothesis that lacidipine treatment can improve endothelial repair capacity of EPCs from hypertensive patients through increasing CXC chemokine receptor four (CXCR4) signaling.

METHODS

In vivo reendothelialization capacity of EPCs from hypertensive patients with or without in vitro lacidipine treatment was examined in a nude mouse model of carotid artery injury. Expression of CXCR4 and alteration in migration and adhesion functions of EPCs were evaluated.

RESULTS

Basal CXCR4 expression was markedly reduced in EPCs from hypertensive patients compared with normal subjects. In parallel, the phosphorylation of Janus kinase-2 (JAK-2) of EPCs, a CXCR4 downstream signaling, was also significantly decreased. Lacidipine promoted CXCR4/JAK-2 signaling expression of in vitro EPCs. Transplantation of EPCs pretreated with lacidipine significantly accelerated in vivo reendothelialization. The enhanced in vitro function and in vivo reendothelialization capacity of EPCs were inhibited by shRNA-mediated knockdown of CXCR4 expression or pretreatment with JAK-2 inhibitor AG490, respectively. In hypertensive patients, lacidipine treatment for 4 weeks also resulted in an upregulation of CXCR4/JAK-2 signaling of EPCs, which was associated with augmented EPCs-mediated reendothelialization and improved endothelial function.

CONCLUSION

Deterioration of CXCR4 signaling may lead to impaired EPCs-mediated reendothelialization of hypertensive patients. Lacidipine-modified EPCs via a partially CXCR4 signaling contribute to enhanced endothelial repair capacity in hypertension.