Endothelial Progenitor Cells for Diagnosis and Prognosis in Cardiovascular Disease

The Role of Stem Cells as Therapeutics for Ischaemic Stroke

Stroke remains one of the leading causes of death and disability worldwide. Current reperfusion treatments for ischaemic stroke are limited due to their narrow therapeutic window in rescuing ischaemic penumbra. Stem cell therapy offers a promising alternative. As a regenerative medicine, stem cells offer a wider range of treatment strategies, including long-term intervention for chronic patients, through the reparation and replacement of injured cells via mechanisms of differentiation and proliferation. The purpose of this review is to evaluate the therapeutic role of stem cells for ischaemic stroke. This paper discusses the pathology during acute, subacute, and chronic phases of cerebral ischaemic injury, highlights the mechanisms involved in mesenchymal, endothelial, haematopoietic, and neural stem cell-mediated cerebrovascular regeneration, and evaluates the pre-clinical and clinical data concerning the safety and efficacy of stem cell-based treatments. The treatment of stroke patients with different types of stem cells appears to be safe and efficacious even at relatively higher concentrations irrespective of the route and timing of administration. The priming or pre-conditioning of cells prior to administration appears to help augment their therapeutic impact. However, larger patient cohorts and later-phase trials are required to consolidate these findings.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Effects of Sacubitril/Valsartan on cardiac function, blood biochemistry and clinical efficacy in early ventricular remodeling after acute myocardial infarction

Ventricular remodeling (VR) after acute ST-elevation myocardial infarction (STEMI) is an important predictor for medium- and long-term prognosis. This study focuses on the relevant indexes of VR in patients with AMI, in which, the intervention effects of sacubitril/valsartan and enalapril were compared, guiding the clinical treatment. 58 patients with acute STEMI treated with PCI were divided into research group and control group. UCG was performed at 1 week, 1 month and 3 months after MI, and the patients' indexes were collected to compare VR and adverse reactions in the two groups. The test results showed that there was no statistical difference in the baseline data of patients in the two groups, which were comparable. In the blood biochemical index examination, no statistical difference was found in cTnI and NT-proBNP between the two groups. At 1 week after operation, the levels of cTnI and NT-proBNP in research group were lower than those in the control group. In ECG examination, there was no statistical significance in the levels of LVEF, LVEDD and LVESD at admission between the two groups. After 1 week, the results of LVEF, LVEDD, LVESD in the research group were higher than those in the control group. The results of this study show that sacubitril/valsartan can be used in patients with AMI instead of enalapril. Sacubitril/valsartan improves cardiac function in patients with emergency percutaneous coronary intervention (PCI) for AMI, inhibits ventricular remodeling, and has a low incidence of adverse cardiac events and adverse drug reactions.

Culture of leukocyte-derived cells from human peripheral blood: Increased expression of pluripotent genes OCT4, NANOG, SOX2, self-renewal gene TERT and plasticity

There are few stem cells in human peripheral blood (PB). Increasing the population and plasticity of stem cells in PB and applying it to regenerative medicine require suitable culture methods. In this study, leukocyte populations 250 mL of PB were collected using a blood separator before that were cultured in optimal cell culture medium for 4 to 7 days. After culturing, stemness characteristics were analyzed, and red blood cells were removed from the cultured cells. In our results, stemness markers of the leukocyte populations Sca-1+ CD45+, CD117+ CD45+, and very small embryonic-like stem cells CD34+ Lin- CD45- and CXCR4+ Lin- CD45- were significantly increased. Furthermore, the expression of stem cell genes OCT4 (POU5F1), NANOG, SOX2, and the self-renewal gene TERT was analyzed by quantitative real-time polymerase chain reaction in these cells, and it showed a significant increase. These cells could be candidates for multi-potential cells and were further induced using trans-differentiation culture methods. These cells showed multiple differentiation potentials for osteocytes, nerve cells, cardiomyocytes, and hepatocytes. These results indicate that appropriate culture methods can be applied to increase expression of pluripotent genes and plasticity. Leukocytes of human PB can be induced to trans-differentiate into pluripotent potential cells, which will be an important breakthrough in regenerative medicine.

The Long Telling Story of "Endothelial Progenitor Cells": Where Are We at Now?

Endothelial progenitor cells (EPCs): The name embodies years of research and clinical expectations, but where are we now? Do these cells really represent the El Dorado of regenerative medicine? Here, past and recent literature about this eclectic, still unknown and therefore fascinating cell population will be discussed. This review will take the reader through a temporal journey that, from the first discovery, will pass through years of research devoted to attempts at their definition and understanding their biology in health and disease, ending with the most recent evidence about their pathobiological role in cardiovascular disease and their recent applications in regenerative medicine.

Exploring Endothelial Colony-Forming Cells to Better Understand the Pathophysiology of Disease: An Updated Review

Endothelial cell (EC) dysfunction has been implicated in a variety of pathological conditions. The collection of ECs from patients is typically conducted postmortem or through invasive procedures, such as surgery and interventional procedures, hampering efforts to clarify the role of ECs in disease onset and progression. In contrast, endothelial colony-forming cells (ECFCs), also termed late endothelial progenitor cells, late outgrowth endothelial cells, blood outgrowth endothelial cells, or endothelial outgrowth cells, are obtained in a minimally invasive manner, namely, by the culture of human peripheral blood mononuclear cells in endothelial growth medium. ECFCs resemble mature ECs phenotypically, genetically, and functionally, making them excellent surrogates for ECs. Numerous studies have been performed that examined ECFC function in conditions such as coronary artery disease, diabetes mellitus, hereditary hemorrhagic telangiectasia, congenital bicuspid aortic valve disease, pulmonary arterial hypertension, venous thromboembolic disease, and von Willebrand disease. Here, we provide an updated review of studies using ECFCs that were performed to better understand the pathophysiology of disease. We also discuss the potential of ECFCs as disease biomarkers and the standardized methods to culture, quantify, and evaluate ECFCs and suggest the future direction of research in this field.

Endothelial Progenitor Cell Response to Acute Multicomponent Exercise Sessions with Different Durations

It is widely accepted that exercise training has beneficial effects on vascular health. Although a dose-dependent relation has been suggested, little is known about the effects of different exercise durations on endothelial markers. This study aimed to assess the effect of single exercise sessions with different durations in the circulating levels of endothelial progenitor cells (EPCs) and endothelial cells (CECs) among adults with cardiovascular risk factors. Ten participants performed two multicomponent exercise sessions, one week apart, lasting 30 and 45 min (main exercise phase). Before and after each exercise session, blood samples were collected to quantify EPCs and CECs by flow cytometry. The change in EPCs was significantly different between sessions by 3.0% (95% CI: 1.3 to 4.7), being increased by 1.8 ± 1.7% (p = 0.009) in the 30 min session vs. −1.2 ± 2.0% (p > 0.05) in the 45 min session. No significant change was observed in CECs [−2.0%, 95%CI: (−4.1 to 0.2)] between the sessions. In conclusion, a multicomponent exercise session of 30 min promotes an acute increase in the circulating levels of EPCs without increasing endothelial damage (measured by the levels of CECs) among adults with cardiovascular risk factors.

Empagliflozin does not reverse lipotoxicity-induced impairment in human myeloid angiogenic cell bioenergetics

Background

Empagliflozin can curb inflammation and oxidative stress, through sodium-proton exchanger (NHE) inhibition, in a model of lipotoxicity in human myeloid angiogenic cells (MAC), which mediate endothelial repairing processes. Aim of this study is to assess in human MAC whether: (1) Stearic acid (SA) induced inflammation and increase in oxidant stress is accompanied by bioenergetic alterations; (2) empagliflozin anti-lipotoxic action is concomitant with coherent changes in bioenergetic metabolism, possibly via NHE blockade.

Methods

MAC were isolated from peripheral blood of healthy volunteers and incubated in the presence/absence of SA (100 μM for 3 h) with/without empagliflozin (EMPA 100 μM) or amiloride (Ami 100 μM) for 1 h. Cell respiration (oxygen consumption rate OCR) and anaerobic glycolysis (measured as proton production rate) were recorded in real-time by Seahorse technology, and ATP production (anaerobic glycolysis- and oxphos-derived) rates were calculated.

Results

SA, at the concentration causing inflammation and increased oxidant stress, altered cell bioenergetics of human MAC, with overall reductions in basal OCR and oxphos-derived ATP production (all p < 0.05), pointing to mitochondrial alterations. EMPA, at the concentration counteracting SA-induced lipotoxicity, both alone and in the presence of SA, caused NHE-independent extensive bioenergetic alterations (from p < 0.05 to p < 0.01), greater than those induced by SA alone.

Conclusions

In human MAC: (1) SA altered cell bioenergetics, concomitantly with inflammation and oxidant stress; (2) EMPA possibly inhibited mitochondrial respiration, (3) the protective effect of EMPA against SA-induced lipotoxicity was unlikely to be mediated through bioenergetic metabolism.

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.

Assessment of the Relationship Between CD34 Antigen and Vitamin D Level and Insulin Resistance in Patients With Type 2 Diabetes

Diabetes causes disorders in the performance of endothelial progenitor cells, and obesity and vitamin D deficiency are associated with endothelial dysfunction and cardiovascular disease. This case-control study investigated the relationship between serum CD34 antigen and vitamin D levels and insulin resistance in type 2 diabetes. The results showed that CD34 has a significant inverse relationship with BMI, A1C, fasting blood glucose, insulin resistance, and insulin levels and has a significant direct relationship with vitamin D levels. Both CD34 and vitamin D were found to be significantly associated with type 2 diabetes. The association between reduced CD34 and vitamin D levels with type 2 diabetes and increased insulin resistance suggests that these parameters may be helpful in assessing diabetes and predicting its complications.

Endothelial progenitor cells predict vascular damage progression in naive hypertensive patients according to sex

Low levels of endothelial progenitor cells (EPCs) are associated with cardiovascular (CV) morbidity and mortality. Early indicators of vascular damage represent independent predictors of CV prognosis. The aim of this study was to evaluate the possible association of EPCs and circulating cytokine levels with vascular damage markers in naive hypertensive patients according to sex and to evaluate the role of EPCs in vascular damage progression. We enrolled 60 subjects; circulating EPCs were determined by cytometric analysis, and serum cytokines were determined by chemiluminescence microarray technology. Endothelial function was estimated with the measurement of the reactive hyperemia index (RHI), arterial stiffness (AS) was evaluated with the measurement of carotid-femoral pulse wave velocity (PWV) and carotid intima-media thickness (IMT) was determined by a high-resolution ultrasound B-mode system. Patients were evaluated at baseline and after an average follow-up of 3.0 ± 0.6 years. RHI was correlated with EPCs and inversely related to HOMA, TNF-α, IL-6, hs-CRP, and IL-1β. PWV was positively correlated with HOMA, TNF-α, IL-6, IL-1β, and hs-CRP, and it was inversely related to EPCs. An inverse relationship was observed between c-IMT and EPCs and e-GFR. EPCs were the major predictor of the RHI and PWV. After adjustment for vascular index basal values and the other covariates, EPCs explained 17.0%, 27.7%, and 10.6% of the variability in ΔRHI, ΔPWV, and Δc-IMT at follow-up, respectively. Our study results support the hypothesis of an etiological link between circulating EPCs and morphofunctional vascular parameters in hypertensive subjects. Of interest, circulating EPCs, after adjusting for possible confounding factors, may indicate vascular damage progression.

A Novel Silicon Platform for Selective Isolation, Quantification, and Molecular Analysis of Small Extracellular Vesicles

Introduction

Small extracellular vesicles (sEVs), thanks to their cargo, are involved in cellular communication and play important roles in cell proliferation, growth, differentiation, apoptosis, stemness and embryo development. Their contribution to human pathology has been widely demonstrated and they are emerging as strategic biomarkers of cancer, neurodegenerative and cardiovascular diseases, and as potential targets for therapeutic intervention. However, the use of sEVs for medical applications is still limited due to the selectivity and sensitivity limits of the commonly applied approaches.

Methods

Novel sensing solutions based on nanomaterials are arising as strategic tools able to surpass traditional sensor limits. Among these, Si nanowires (Si NWs), realized with cost-effective industrially compatible metal-assisted chemical etching, are perfect candidates for sEV detection.

Results

In this paper, the realization of a selective sensor able to isolate, concentrate and quantify specific vesicle populations, from minimal volumes of biofluid, is presented. In particular, this Si NW platform has a detection limit of about 2×10⁵ sEVs/mL and was tested with follicular fluid and blastocoel samples. Moreover, the possibility to detach the selectively isolated sEVs allowing further analyses with other approaches was demonstrated by SEM analysis and several PCRs performed on the RNA content of the detached sEVs.

Discussion

This platform overcomes the limit of detection of traditional methods and, most importantly, preserves the biological content of sEVs, opening the route toward a reliable liquid biopsy analysis.

Advances of Endothelial Progenitor Cells in the Development of Depression

Depression is a major psychological disease of human beings. With the severity of depression, it elevates the risk of cardiovascular disease (CVD), especially acute coronary syndrome (ACS), resulting in serious harm to human health. The number of endothelial progenitor cells (EPCs) is closely related to the development of depression. It has been reported that the number of peripheral blood EPCs in patients with depression was reduced. However, effects on the function of EPCs in depression are still unclear. This paper aims to analyze and summarize the research of EPCs in depression, and we envision that EPCs might act as a new target for evaluating the severity of depression and its complications.

Macrophage phenotype and function are dependent upon the composition and biomechanics of the local cardiac tissue microenvironment

Macrophage accumulation and nitrosative stress are known mechanisms underlying age-related cardiovascular pathology and functional decline. The cardiac muscle microenvironment is known to change with age, yet the direct effects of these changes have yet to be studied in-depth. The present study sought to better elucidate the role that biochemical and biomechanical alterations in cardiac tissue have in the altered phenotype and functionality of cardiac resident macrophages observed with increasing age. To accomplish this, naïve bone marrow derived macrophages from young mice were seeded onto either functionalized poly-dimethyl-siloxane hydrogels ranging in stiffness from 2kPA to 64kPA or onto tissue culture plastic, both of which were coated with either young or aged solubilized mouse cardiac extracellular matrix (cECM). Both biomechanical and biochemical alterations were found to have a significant effect on macrophage polarization and function. Increased substrate stiffness was found to promote macrophage morphologies associated with pro-inflammatory macrophage activation, increased expression of pro-inflammatory inducible nitric oxide synthase protein with increased nitric oxide secretion, and attenuated arginase activity and protein expression. Additionally, exposure to aged cECM promoted attenuated responsivity to both canonical pro-inflammatory and anti-inflammatory cytokine signaling cues when compared to young cECM treated cells. These results suggest that both biomechanical and biochemical changes in the cardiovascular system play a role in promoting the age-related shift towards pro-inflammatory macrophage populations associated with cardiovascular disease development.

Endocan and Circulating Progenitor Cells in Women with Systemic Sclerosis: Association with Inflammation and Pulmonary Hypertension

Background: Systemic sclerosis (SSc) is characterized by early vasculopathy and fibrosis in the skin, lungs, and other tissues. Vascular manifestations of SSc include Raynaud’s phenomenon, digital ulcers, and pulmonary artery hypertension (PAH). PAH is the second most common cause of mortality in SSc. Circulating CD34+ cells associated with cardiovascular health status in several conditions, including chronic immune-inflammatory disease. CD34+ cell numbers have been found inconstantly reduced in SSc. Endocan, a proteoglycan expressed by endothelial cells, was recently suggested as a marker of vascular stress. We tested the relationships among CD34+ cells, endocan, inflammatory markers, vitamin D levels, and clinical parameters in SSc patients with PAH. METHODS: Standard echocardiography was performed. Vitamin D levels, CD34+ cells, inflammatory markers, endocan plasma levels were determined in 36 female SSc patients (24 diffuse/12 limited) and 36 matched controls (HC). RESULTS: We found no difference in CD34+ and vitamin D levels in SSc as compared to controls; ESR, CRP, fibrinogen, endocan, sPAP were higher in SSc with respect to controls. We found a correlation between endocan and: CD34+ cells (r: −0.540, p = 0.002), pulmonary arterial pressure (sPAP) (r: 0.565, p < 0.001), tricuspid annular plane excursion (TAPSE) (r: −0.311, p < 0.01), and E/A ratio (r: −0.487, p < 0.001), but not with ejection fraction (r: −0.057, p = 0.785) in SSc. CD34+ cells correlate with fibrinogen (r: −0.619, p < 0.001), sPAP (r: −0.404, p = 0.011), E/A (r: 0.470, p < 0.005 in SSc. CONCLUSION: CD34+ cell number was significantly correlated with endocan levels and with sPAP in SSc; endocan and CD34+ progenitor cells might be suggested as a potential marker of disease status.

Endothelial Progenitor Cells as a Potential Biomarker in Interstitial Lung Disease Associated with Rheumatoid Arthritis

Interstitial lung disease (ILD) increases morbidity and mortality in patients with rheumatoid arthritis (RA). Although the pathogenesis of ILD associated with RA (RA-ILD⁺) remains poorly defined, vascular tissue is crucial in lung physiology. In this context, endothelial progenitor cells (EPC) are involved in endothelial tissue repair. However, little is known about their implication in RA-ILD⁺. Accordingly, we aimed to investigate the potential role of EPC related to endothelial damage in RA-ILD⁺. EPC quantification in peripheral blood from 80 individuals (20 RA-ILD⁺ patients, 25 RA-ILD^- patients, 21 idiopathic pulmonary fibrosis (IPF) patients, and 14 healthy controls) was performed by flow cytometry. EPC were considered as CD34⁺, CD45^low, CD309⁺ and CD133⁺. A significant increase in EPC frequency in RA-ILD⁺ patients, as well as in RA-ILD^- and IPF patients, was found when compared with controls (p < 0.001, p = 0.02 and p < 0.001, respectively). RA-ILD⁺ patients exhibited a higher EPC frequency than the RA-ILD^- ones (p = 0.003), but lower than IPF patients (p < 0.001). Our results suggest that EPC increase may represent a reparative compensatory mechanism in patients with RA-ILD⁺. The degree of EPC frequency may help to identify the presence of ILD in RA patients and to discriminate RA-ILD⁺ from IPF.

Mediterranean diet and endothelial function in patients with coronary heart disease: An analysis of the CORDIOPREV randomized controlled trial

BACKGROUND

Endothelial dysfunction is a crucial step in atherosclerosis development, and its severity is determinant for the risk of cardiovascular recurrence. Diet may be an effective strategy to protect the endothelium, although there is no consensus about the best dietary model. The CORonary Diet Intervention with Olive oil and cardiovascular PREVention (CORDIOPREV) study is an ongoing prospective, randomized, single-blind, controlled trial in 1,002 coronary heart disease (CHD) patients, whose primary objective is to compare the effect of 2 healthy dietary patterns (low-fat versus Mediterranean diet) on the incidence of cardiovascular events. Here, we report the results of one secondary outcome of the CORDIOPREV study: to evaluate the effect of these diets on endothelial function, assessed by flow-mediated dilation (FMD) of the brachial artery.

METHODS AND FINDINGS

From the total participants taking part in the CORDIOPREV study, 805 completed endothelial function study at baseline and were randomized to follow a Mediterranean diet (35% fat, 22% monounsaturated fatty acids [MUFAs], and <50% carbohydrates) or a low-fat diet (28% fat, 12% MUFAs, and >55% carbohydrates), with endothelial function measurement repeated after 1 year. As secondary objectives and to explore different underlying mechanisms in the modulation of endothelial function, we quantified endothelial microparticles (EMPs) and endothelial progenitor cells (EPCs) and evaluated, in 24 preselected patients, in vitro cellular processes related to endothelial damage (reactive oxygen species, apoptosis, and senescence) and endothelial repair (cell proliferation and angiogenesis), as well as other modulators (micro-RNAs [miRNAs] and proteins). Patients who followed the Mediterranean diet had higher FMD (3.83%; 95% confidence interval [CI]: 2.91-4.23) compared with those in the low-fat diet (1.16%; 95% CI: 0.80 to 1.98) with a difference between diets of 2.63% (95% CI: 1.89-3.40, p = 0.011), even in those patients with severe endothelial dysfunction. We observed higher EPC levels (group difference: 1.64%; 95% CI: 0.79-2.13, p = 0.028) and lower EMPs (group difference: -755 EMPs/μl; 95% CI: -1,010 to -567, p = 0.015) after the Mediterranean diet compared with the low-fat diet in all patients. We also observed lower intracellular reactive oxygen species (ROS) production (group difference: 11.1; 95% CI: 2.5 to 19.6, p = 0.010), cellular apoptosis (group difference: -20.2; 95% CI: -26.7 to -5.11, p = 0.013) and senescence (18.0; 95% CI: 3.57 to 25.1, p = 0.031), and higher cellular proliferation (group difference: 11.3; 95% CI: 4.51 to 13.5, p = 0.011) and angiogenesis (total master segments length, group difference: 549; 95% CI: 110 to 670, p = 0.022) after the Mediterranean diet than the low-fat diet. Each dietary intervention was associated with distinct changes in the epigenetic and proteomic factors that modulate biological process associated with endothelial dysfunction. The evaluation of endothelial function is a substudy of the CORDIOPREV study. As in any substudy, these results should be treated with caution, such as the potential for false positives because of the exploratory nature of the analyses.

CONCLUSIONS

Our results suggest that the Mediterranean diet better modulates endothelial function compared with a low-fat diet and is associated with a better balance of vascular homeostasis in CHD patients, even in those with severe endothelial dysfunction.

CLINICAL TRIAL REGISTRATION

URL, http://www.cordioprev.es/index.php/en. clinicaltrials.gov number NCT00924937.

Intrinsic Vascular Repair by Endothelial Progenitor Cells in Acute Coronary Syndromes: an Update Overview

Bone marrow-derived endothelial progenitor cells (EPCs) play a key role in the maintenance of endothelial homeostasis and endothelial repair at areas of vascular damage. The quantification of EPCs in peripheral blood by flow cytometry is a strategy to assess this reparative capacity. The number of circulating EPCs is inversely correlated with the number of cardiovascular risk factors and to the occurrence of cardiovascular events. Therefore, monitoring EPCs levels may provide an accurate assessment of susceptibility to cardiovascular injury, greatly improving risk stratification of patients with high cardiovascular risk, such as those with an acute myocardial infarction. However, there are many issues in the field of EPC identification and quantification that remain unsolved. In fact, there have been conflicting protocols used to the phenotypic identification of EPCs and there is still no consensual immunophenotypical profile that corresponds exactly to EPCs. In this paper we aim to give an overview on EPCs-mediated vascular repair with special focus on acute coronary syndromes and to discuss the different phenotypic profiles that have been used to identify and quantify circulating EPCs in several clinical studies. Finally, we will synthesize evidence on the prognostic role of EPCs in patients with high cardiovascular risk.

Sodium-glucose cotransporter 2 inhibitors antagonize lipotoxicity in human myeloid angiogenic cells and ADP-dependent activation in human platelets: potential relevance to prevention of cardiovascular events

BACKGROUND

The clear evidence of cardiovascular benefits in cardiovascular outcome trials of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in type 2 diabetes might suggest an effect on atherosclerotic plaque vulnerability and/or thrombosis, in which myeloid angiogenic cells (MAC) and platelets (PLT) are implicated. We tested the effects of SGLT2i on inflammation and oxidant stress in a model of stearic acid (SA)-induced lipotoxicity in MAC and on PLT activation. The possible involvement of the Na⁺/H⁺ exchanger (NHE) was also explored.

METHOD

MAC and PLT were isolated from peripheral blood of healthy subjects and incubated with/without SGLT2i [empagliflozin (EMPA) and dapagliflozin (DAPA) 1-100 μM] to assess their effects on SA (100 μM)-induced readouts of inflammation, oxidant stress and apoptosis in MAC and on expression of PLT activation markers by flow-cytometry after ADP-stimulation. Potential NHE involvement was tested with amiloride (aspecific NHE inhibitor) or cariporide (NHE1 inhibitor). Differences among culture conditions were identified using one-way ANOVA or Friedman test.

RESULTS

NHE isoforms (1,5-9), but not SGLT2 expression, were expressed in MAC and PLT. EMPA and DAPA (100 μM) significantly reduced SA-induced inflammation (IL1β, TNFα, MCP1), oxidant stress (SOD2, TXN, HO1), but not apoptosis in MAC. EMPA and DAPA (both 1 μM) reduced PLT activation (CD62p and PAC1 expression). SGLT2i effects were mimicked by amiloride, and only partially by cariporide, in MAC, and by both inhibitors in PLT.

CONCLUSIONS

EMPA and DAPA ameliorated lipotoxic damage in stearate-treated MAC, and reduced ADP-stimulated PLT activation, potentially via NHE-inhibition, thereby pointing to plaque stabilization and/or thrombosis inhibition as potential mechanism(s) involved in SGLT2i-mediated cardiovascular protection.

Circulating angiogenic cells in glioblastoma: toward defining crucial functional differences in CAC-induced neoplastic versus reactive neovascularization

Background

In order to identify suitable therapeutic targets for glioma anti-angiogenic therapy, the process of neovascularization mediated by circulating angiogenic cells (CACs) needs to be scrutinized.

Methods

In the present study, we compared the expression of neovascularization-related genes by 3 circulating CAC subsets (hematopoietic progenitor cells [HPCs], CD34⁺, and KDR⁺ cells; internal controls: peripheral blood mononuclear cells and circulating endothelial cells) of treatment-naïve patients with glioblastoma (GBM) to those of patients undergoing reactive neovascularization (myocardial infarction (MI). CACs from umbilical cord (representing developmental neovascularization) and healthy subjects served as controls. Fluorescent-activated cell sorting was used to isolate CACs, RT-PCR to determine the expression levels of a panel of 48 neovascularization-related genes, and Luminex assays to measure plasma levels of 21 CAC-related circulating molecules.

Results

We found essential differences in gene expression between GBM and MI CACs. GBM CACs had a higher expression of proangiogenic factors (especially, KITL, CXCL12, and JAG1), growth factor and chemotactic receptors (IGF1R, TGFBR2, CXCR4, and CCR2), adhesion receptor monomers (ITGA5 and ITGA6), and matricellular factor POSTN. In addition, we found major differences in the levels of neovascularization-related plasma factors. A strong positive correlation between plasma MMP9 levels and expression of CXCR4 in the CAC subset of HPCs was found in GBM patients.

Conclusions

Our findings indicate that CAC-mediated neovascularization in GBM is characterized by more efficient CAC homing to target tissue and a more potent proangiogenic response than in physiologic tissue repair in MI. Our findings can aid in selecting targets for therapeutic strategies acting against GBM-specific CACs.

TERT assists GDF11 to rejuvenate senescent VEGFR2+/CD133+ cells in elderly patients with myocardial infarction

Growth differentiation factor 11 (GDF11) is a transforming growth factor β superfamily member with a controversial role in rejuvenating old stem cells after acute injury in the elderly population. This study aimed to evaluate the effects of telomerase reverse transcriptase (TERT) on GDF11-mediated rejuvenation of senescent late-outgrowth endothelial progenitor cells (EPCs), defined as VEGFR2⁺/CD133⁺ cells, in elderly patients with acute myocardial infarction (AMI). We compared the quantity and capabilities of VEGFR2⁺/CD133⁺ cells from old (>60 years), middle-aged (45-60 years), and young (<45 years) AMI patients. The decline in circulating count and survival of VEGFR2⁺/CD133⁺ cells with age was accompanied by decrease in their TERT and GDF11 expression levels in patients with AMI. Further, upregulation of TERT could trigger GDF11-mediated rejuvenation of old VEGFR2⁺/CD133⁺ cells by renewing their survival and angiogenic abilities through activation of canonical (Smad2/3) and noncanonical (eNOS) signaling pathways. Depletion of GDF11 or TERT caused senescence of young VEGFR2⁺/CD133⁺ cells leading to impaired vascular function and angiogenesis in vitro and in vivo, whereas adTERT and rhGDF11 rescued this senescence. TERT cooperates with GDF11 to enhance regenerative capabilities of old VEGFR2⁺/CD133⁺ cells. When combined with TERT, GDF11 may represent a potential therapeutic target for the treatment of elderly patients with MI.

Resveratrol Induces Endothelial Progenitor Cells Angiogenesis via MiR-542-3p by Targeting Angiopoietin-2 and Involves in Recanalization of Venous Thrombosis

Background

Endothelial progenitor cells (EPCs) play an important role in therapeutic angiogenesis. Besides, resveratrol (RSV) exerts many pharmacological functions in regulation of cell function. Furthermore, microRNAs (miRNAs) have been considered to be of great significance in biological process. In this study, we aimed to investigate the effect of RSV on EPCs and its potential mechanism that involved in recanalization of venous thrombosis.

Material/Methods

EPCs were treated with RSV, and angiogenic functions was evaluated by tube formation and migration assays. miR-542-3p expression level in EPCs was assessed and exogenously modified. Bioinformatic analysis was applied to detect the potential target of miR-542-3p. Effects of RSV treatment in vivo venous thrombosis rat model were evaluated.

Results

RSV enhanced angiogenic function of EPCs and decreased expression of miR-542-3p. Dual luciferase reporter gene and western blot results confirmed angiopoietin-2 (ANGPT2) was a direct target of miR-542-3p. It was found that inhibition of miR-542-3p contributed to angiogenesis of EPCs and elevated ANGPT2 protein level. Finally, in a rat model of venous thrombosis, RSV-treated EPCs promoted recanalization of thrombi.

Conclusions

We demonstrated that RSV can contribute to progenitor cells angiogenesis via miR-542-3p by targeting ANGPT2, subsequently enhanced recanalization of thrombi.

Circulating levels of CD34+ cells predict long-term cardiovascular outcomes in patients on maintenance hemodialysis

CD34+ cells maintain vascular homeostasis and predict cardiovascular outcomes. We previously evaluated the association of CD34+ cells with cardiovascular disease (CVD) events over 23 months, but long-term CVD outcomes in relation to levels of CD34+ cells in patients on maintenance hemodialysis are unclear. Herein, we analyzed the long-term predictive potential levels of CD34+ cells for CVD outcomes and all-cause mortality. Between March 2005 and May 2005, we enrolled 215 patients on maintenance hemodialysis at Nagoya Kyoritsu Hospital and followed them up to 12.8 years. According to the CD34+ cell counts, patients were classified into the lowest, medium, and highest tertiles. Levels of CD34+ cells were analyzed in association with four-point major adverse CV events (MACEs), CVD death, and all-cause mortality. In univariate analysis age, smoking habit, lower geriatric nutrition risk index, lower calcium × phosphate product, and lower intact parathyroid hormone were significantly associated with the lowest tertile. Whereas, in multivariate analysis, age and smoking habit were significantly associated with the lowest tertile. Among 139 (64.7%) patients who died during a mean follow-up period of 8.0 years, 39 (28.1%) patients died from CVD. Patients in the lowest tertile had a significantly lower survival rate than those in the medium and highest tertiles (p ≤ 0.001). Using multivariable analyses, the lowest tertile was significantly associated with four-point MACEs (hazard ratio 1.80, p = 0.023) and CVD death (hazard ratio 2.50, p = 0.011). In conclusion, our long-term observational study revealed that a low level of CD34+ cells in the circulation predicts CVD outcomes among patients on maintenance hemodialysis.

Increased expression of Sonic hedgehog restores diabetic endothelial progenitor cells and improves cardiac repair after acute myocardial infarction in diabetic mice

Damaged endothelial progenitor cells (EPCs) are associated with poor prognosis in diabetic myocardial infarction (DMI). Our previous studies revealed that an impaired Sonic hedgehog (Shh) pathway contributes to insufficient function in diabetic EPCs; however, the roles of the Shh pathway in diabetic EPC apoptosis under basal and hypoxic/ischemic conditions remain unknown. Therefore, the present study investigated whether Shh revitalized diabetic EPCs and consequently improved the deteriorative status of DMI. For this purpose, streptozotocin injection was used in male C57/BL6 mice to induce type-1 diabetes, and diabetic EPCs were isolated from the bone marrow. Apoptosis, cell function, and protein expression were investigated in EPCs in vitro. Mouse hearts were injected with adenovirus Shh-modified diabetic EPCs (DM-EPC^Shh) or control DM-EPC^Null immediately after coronary artery ligation in vivo. Cardiac function, capillary numbers, fibrosis, and cell apoptosis were then detected. First, the in vitro results demonstrated that the apoptosis of diabetic EPCs was reduced following treatment with Shh protein for 24 h, under normal or hypoxic conditions. BMI1 proto-oncogene (Bmi1), an antiapoptotic protein found in several cells, was reduced in diabetic EPCs under normal or hypoxic conditions, but was upregulated after Shh protein stimulation. When Bmi1-siRNA was administered, the antiapoptotic effect of Shh protein was significantly reversed. In addition, p53, a Bmi1-targeted gene, was demonstrated to mediate the antiapoptotic effect of the Shh/Bmi1 pathway in diabetic EPCs. The Shh/Bmi1/p53 axis also enhanced the diabetic EPC function. In vivo, Shh-modified diabetic EPCs exhibited increased EPC retention and decreased apoptosis at 3 days post-DMI. At 14 days post-DMI, these cells presented enhanced capillary density, reduced myocardial fibrosis and improved cardiac function. In conclusion, the present results demonstrated that the Shh pathway restored diabetic EPCs through the Shh/Bmi1/p53 axis, suppressed myocardial apoptosis and improved myocardial angiogenesis, thus reducing cardiac fibrosis and finally restoring myocardial repair and cardiac function in DMI. Thus, the Shh pathway may serve as a potential target for autologous cell therapy in diabetic myocardial ischemia.

Hyperhomocysteinemia induced endothelial progenitor cells dysfunction through hyper-methylation of CBS promoter

Bone marrow (BM)-derived endothelial progenitor cells (EPCs) are the key players in angiogenesis and vascular function. Cystathionine-β-synthase (CBS), an H₂S-generating enzyme in methionine metabolism, regulates the function of these EPCs. This study aims to examine whether CBS hyper-methylation contributes to the bone marrow endothelial progenitor cell (BM-EPCs) function and subsequent bone blood flow in mice fed with a high methionine diet (HMD). Bone marrow (BM) cells were collected from HMD and control mice, differentiated into BM-EPCs, and were characterized by acLDL-DiI labeling. CBS mRNA expression was analyzed by real-time PCR, and the global methylation status and methylation of the CBS promoter were detected by nuclear 5-mC assay and methylation-specific PCR (qMSP) respectively. The result reveals that CBS promoter in BM-EPCs from HMD mice was hyper-methylated and the methylation level was, indeed, negatively correlated with CBS mRNA and angiogenic function of BM-EPCs. In addition, global methylation (5-mC) and DNA methyltransferase-1 (DNMT1) expression were increased in HMD condition. In vitro study also shows that HMD induced hyperhomocysteinemia (HHcy) impaired both adhesion and angiogenesis properties of BM-EPCs, accompanied by higher methylation level of CBS promoter that compared to control. Furthermore, bone blood flow was found to be decreased in HMD mice as compared to wild-type mice. To dissect the epigenetic mechanism, we also administrated DNMT inhibitor, 5-azacytidine (5-Aza) to HMD mice. The administration of 5-Aza in HMD mice restored the CBS expression, EPC mediated angiogenesis and blood flow by reducing abnormal DNA hyper-methylation. In conclusion, HHcy dismantles BM-EPCs function and bone blood flow through the hyper-methylation of the CBS promoter in HMD fed mice.

17β-estradiol promotes recovery after myocardial infarction by enhancing homing and angiogenic capacity of bone marrow-derived endothelial progenitor cells through ERα-SDF-1/CXCR4 crosstalking

17β-estradiol (E2) has been shown to mediate endothelial progenitor cells (EPCs) to repair infarcted myocardium. Both estrogen receptor α (ERα) and stromal derived factor-1 (SDF-1)/CXCR4 signaling pathways may play a critical role in regulating homing and angiogenesis of EPCs in this process. However, the interaction between ERα and SDF-1/CXCR4 signaling pathways remains unclear. In response to E2, the expression of SDF-1 and CXCR4 in EPCs from ovariectomized BALB/C mice was obviously up-regulated, in addition, the migration and tube formation of EPCs in vitro were also significantly enhanced. However, ERα antagonist (MMP) and CXCR4 inhibitor (AMD3100) significantly decreased the migration and tube length of EPCs, even if mediated by E2. The combined treatment of MMP and AMD3100 exerted more inhibitory effects on migration and tube formation of EPCs induced by E2. In in vivo studies, ovariectomized mice were induced acute myocardial infarction (AMI), and divided into four groups (n = 6): non-preconditioned EPCs (3 × 106) group, E2-preconditioned EPCs group, MMP + AMD3100 preconditioned EPCs group, and EPCs pretreated with E2 + MMP + AMD3100 group. E2 group displayed a greater number of homing EPCs, increased capillary density in infarcted myocardium, decreased left ventricular (LV) fibrosis. Nevertheless, these effects of E2 were almost completely blocked by the combined treatment of MMP and AMD3100. E2 can produce cardiovascular protective effects in AMI setting by enhancing homing and angiogenic capacity of EPCs through ERα and CXCR4 signaling pathways, which means that ERα and CXCR4 pathways are effective targets for the development of treatment strategies for AMI.

Salvianolic Acid B-Alleviated Angiotensin II Induces Cardiac Fibrosis by Suppressing NF-κB Pathway In Vitro

BACKGROUND Salvianolic acid B (SalB) is the representative component of phenolic acids derived from the roots and rhizomes of Salvia miltiorrhiza Bge (Labiatae), which has been used widely in Asian countries for clinical therapy of various cardiovascular dysfunction-related diseases. However, cardiac protection effects and the underlying mechanism for clinical application are still poorly understood. Here, we investigated the potential anti-myocardial fibrosis effect and mechanism of SalB on Angiotensin II (Ang II)-induced cardiac fibrosis in vitro. MATERIAL AND METHODS The proliferation and migration capacity of cardiac fibroblasts (CFBs) were measured by MTT assay and scratch analysis, respectively. The colorimetric assay determined the hydroxyproline content in medium. Western blotting detected the protein expressions of nuclear transcription factor-kappa B (NF-κB) pathway-associated proteins, fibronectin (FN), collagen type I (Coll I), α-smooth muscle actin (α-SMA), and connective tissue growth factor (CTGF). The expression of α-SMA protein was observed by immunofluorescence staining. qRT-PCR detected the mRNA expression of NF-κB. RESULTS SalB attenuated Ang II-induced the proliferation and the migration ability of CFBs. Ang II-induced the extracellular matrix protein Coll I, FN, and α-SMA, the pro-fibrotic cytokine CTGF protein expression was inhibited, and the nuclear translocation of NF-κB p65 subunit was reduced by SalB. Western blotting and qRT-PCR confirmed that SalB blocked the activation of NF-κB induced by Ang II. PDTC (the NF-κB inhibitor) also inhibited proliferation of CFBs and reduced α-SMA and Coll I expression induced by Ang II. CONCLUSIONS SalB can alleviate Ang II-induced cardiac fibrosis via suppressing the NF-κB pathway in vitro.

Simultaneous isolation of mesenchymal stem cells and endothelial progenitor cells derived from murine bone marrow

Mesenchymal stem or stromal cells (MSCs) are identified as sources of pluripotent stem cells with varying degrees of plasticity. Endothelial progenitor cells (EPCs) originate from either bone marrow (BM) or peripheral blood and can mature into cells that line the lumen of blood vessels. MSC and EPC therapies exhibit promising results in a variety of diseases. The current study described the simultaneous isolation of EPCs and MSCs from murine BM using a straightforward approach. The method is based on differences in attachment time and trypsin sensitivity of MSCs and EPCs. The proposed method revealed characteristics of isolated cells. Isolated MSCs were positive for cell surface markers, cluster of differentiation (CD)29, CD44 and stem cell antigen-1 (Sca-1), and negative for hematopoietic surface markers, CD45 and CD11b. Isolated EPCs were positive for Sca-1 and vascular endothelial growth factor receptor 2 and CD133. The results indicate that the proposed method ensured simultaneous isolation of homogenous populations of MSCs and EPCs from murine BM.

Endothelial progenitor cells and rheumatic disease modifying therapy

Rheumatic diseases are associated with accelerated atherosclerosis and with increased risk of cardiovascular morbidity and mortality. The mechanisms underlying the higher prevalence of cardiovascular disease are not completely clarified, but it is likely that a pivotal role is played by vascular inflammation and consequently to altered vascular endothelium homeostasis. Also, high prevalence of traditional risk factors, proatherogenic activation and endothelial dysfunction further contribute to vascular damage. Circulating endothelial progenitor cells (EPCs) can restore dysfunctional endothelium and protect against atherosclerotic vascular disease. However, abnormalities in number and function of these cells in patients with rheumatic condition have been extensively reported. During the last years, growing interest in the mechanisms of endothelial renewal and its potential as a therapy for CVD has been shown; in addition, pioneering studies show that EPC dysfunction might be improved with pharmacological strategies. However, how to restore EPC function, and whether achieving this aim may be effective in preventing cardiovascular complications in rheumatic disease, remain to be established. In this review we report an overview on the current stand of knowledge on the effect of pharmaceutical and lifestyle intervention in improving EPCs number and function in rheumatic disease.

S-allylcysteine Improves Blood Flow Recovery and Prevents Ischemic Injury by Augmenting Neovasculogenesis

Studies suggest that a low level of circulating human endothelial progenitor cells (EPCs) is a risk factor for ischemic injury and coronary artery disease (CAD). Consumption of S-allylcysteine (SAC) is known to prevent CAD. However, the protective effects of SAC on the ischemic injury are not yet clear. In this study, we examined whether SAC could improve blood flow recovery in ischemic tissues through EPC-mediated neovasculogenesis. The results demonstrate that SAC significantly enhances the neovasculogenesis of EPCs in vitro. The molecular mechanisms for SAC enhancement of neovasculogenesis include the activation of Akt/endothelial nitric oxide synthase signaling cascades. SAC increased the expression of c-kit, β-catenin, cyclin D1, and Cyclin-dependent kinase 4 (CDK4) proteins in EPCs. Daily intake of SAC at dosages of 0.2 and 2 mg/kg body weight significantly enhanced c-kit protein levels in vivo. We conclude that dietary consumption of SAC improves blood flow recovery and prevents ischemic injury by inducing neovasculogenesis in experimental models.

Human circular RNA‑0054633 regulates high glucose‑induced vascular endothelial cell dysfunction through the microRNA‑218/roundabout 1 and microRNA‑218/heme oxygenase‑1 axes

The aim of the present study was to investigate the relative regulation of human circular RNA‑0054633 (hsa_circ_0054633), microRNA‑218 (miR‑218), roundabout 1 (ROBO1) and heme oxygenase‑1 (HO‑1) in human umbilical vein endothelial cells (HUVECs) in high glucose conditions. Initially, the expression of hsa_circ_0054633 in HUVECs was detected in high glucose conditions by reverse transcription‑quantitative polymerase chain reaction. Next, a small interfering RNA against hsa_circ_0054633 was constructed to investigate the function of jsa_circ_0054633 in HUVECs by transwell migration, cell counting kit‑8, flow cytometry and tube formation assays. In addition, the effect of hsa_circ_0054633 on the expression levels of ROBO1, HO‑1 and vascular endothelial growth factor were examined. The regulation effects of hsa_circ_0054633 on high glucose‑induced HUVEC proliferation, migration, and angiopoiesis were also analyzed. Bioinformatics analysis and dual‑luciferase assay were then used to confirm the direct or specific regulation of hsa_circ_0054633, miR‑218, ROBO1 and HO‑1. It was observed that high glucose levels increased the expression of hsa_circ_0054633, while downregulation of hsa_circRNA‑0054633 increased the high glucose‑induced endothelial cell dysfunction, including proliferation, migration and angiopoiesis suppression. Bioinformatics analysis revealed that the expression of circRNA‑0054633 was able to inhibit miR‑218 expression, which was clarified by the dual‑luciferase assay. It was also demonstrated that downregulating the expression of miR‑218 inhibited the high glucose‑induced endothelial cell dysfunction by promoting the expression of ROBO1 and HO‑1. These results suggest that the expression of hsa_circRNA‑0054633 has a protective effect against high glucose‑induced endothelial cell dysfunction by targeting ROBO1 and HO‑1.

Adiponectin enhances biological functions of vascular endothelial progenitor cells through the mTOR-STAT3 signaling pathway

Adiponectin (APN), an adipose tissue-excreted adipokine, plays protective roles in metabolic and cardiovascular diseases. In this study, the effects and mechanisms of APN on biological functions of rat vascular endothelial progenitor cells (VEPCs) were investigated in vitro. After administrating APN in rat VEPCs, the proliferation was measured by methyl thiazolyl tetrazolium (MTT) method, the apoptotic rate was test by Flow cytometry assay, mRNA expression of B-cell lymphoma-2 (Bcl-2) and vascular endothelial growth factor (VEGF) was determined by real-time reverse transcriptase polymerase chain reaction (RT-PCR), and protein expression of mechanistic target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3) and phospho-STAT3 (pSTAT3) was analyzed by Western blot. It was suggested that APN promoted the optical density (OD) value of VEPCs, enhanced mRNA expression of Bcl-2 and VEGF, and inhibited cell apoptotic rate. Furthermore, protein expression of pSTAT3 was also increased in the presence of APN. Moreover, APN changed-proliferation, apoptosis and VEGF expression of VEPCs were partially suppressed after blocking the mTOR-STAT3 signaling pathway by the mTOR inhibitor XL388. It was indicated that APN promoted biological functions of VEPCs through targeting the mTOR-STAT3 signaling pathway.

Salvia miltiorrhiza: A Potential Red Light to the Development of Cardiovascular Diseases

Salvia miltiorrhiza Bunge, also known as Danshen in Chinese, has been widely used to treat cardiovascular diseases (CVD) in China and other Asia countries. Here, we summarize literatures of the historical traditional Chinese medicine (TCM) interpretation of the action of Salvia miltiorrhiza, its use in current clinical trials, its main phytochemical constituents and its pharmacological findings by consulting Pubmed, China Knowledge Resource Integrated, China Science and Technology Journal, and the Web of Science Databases. Since 2000, 39 clinical trials have been identified that used S. miltiorrhiza in TCM prescriptions alone or with other herbs for the treatment of patients with CVD. More than 200 individual compounds have been isolated and characterized from S. miltiorrhiza, which exhibited various pharmacological activities targeting different pathways for the treatment of CVD in various animal and cell models. The isolated compounds may provide new perspectives in alternative treatment regimes and reveal novel chemical scaffolds for the development of anti-CVD drugs. Meanwhile, there are also some rising concerns of the potential side effects and drug-drug interactions of this plant. The insights gained from this study will help us to better understanding of the actions of this herb for management of cardiovascular disorders. As an herb of red root, S. miltiorrhiza will act as a potential red light to prevent the development of CVD.

Effect of intensive multifactorial treatment on vascular progenitor cells in hypertensive patients

Background

Most hypertensive patients, despite a proper control of their cardiovascular risk factors, have cardiovascular complications, evidencing the importance of controlling and/or reversing target-organ damage. In this sense, endothelial dysfunction has been associated with the presence of cardiovascular risk factors and related cardiovascular outcomes. Since hypertension often clusters with other risk factors such as dyslipemia, diabetes and obesity, in this study we have investigated the effect of intensive multifactorial treatment on circulating vascular progenitor cell levels on high-risk hypertensive patients.

Design

We included108 hypertensive patients receiving intensive multifactorial pharmacologic treatment and dietary recommendations targeting blood pressure, dyslipemia, hyperglycemia and weight for 12 months. After the treatment period, blood samples were collected and circulating levels of endothelial (CD34+/KDR+, CD34+/VE-cadherin+) and smooth muscle (CD14+/endoglin+) progenitor cells were identified by flow cytometry. Additionally, plasma concentration of vascular endothelial growth factor (VEGF) was determined by ELISA.

Results

Most hypertensive patients (61±12 years, 47% men) showed cardiovascular parameters within normal ranges at baseline. Moreover, body mass index and the majority of the biochemical parameters (systolic and diastolic blood pressure, fasting glucose, total cholesterol, HDL-c, LDL-c, creatinine and hs-CRP) significantly decreased overtime. After 12 months of intensive treatment, CD34+/KDR+ and CD14+/endoglin+ levels did not change, but CD34+/VE-cadherin+ cells increased significantly at month 12 [0.9(0.05–0.14)% vs 0.05(0.02–0.09)% P<0.05]. However, VEGF plasma concentration decreased significantly overtime [89.1(53.9–218.7) vs [66.2(47.5–104.6) pg/mL, P<0.05].

Conclusions

Long-term intensive treatment in hypertensive patients further improves cardiovascular risk and increases circulating EPCs, suggesting that these cells could be a therapeutic target.

Aging process, adherence to Mediterranean diet and nutritional status in a large cohort of nonagenarians: Effects on endothelial progenitor cells

BACKGROUND AND AIM

Adherence to the Mediterranean Diet (MD) has been associated with a longer and better life. The aim of this study was to examine the effects of adherence to the MD, and of nutritional habits on endothelial progenitor (EPCs) and circulating progenitor (CPCs) cells in a cohort of nonagenarians enrolled within the Mugello Study, an epidemiological study aimed at investigating both clinically relevant geriatric items and various health issues, including those related to nutritional status.

METHODS AND RESULTS

Four hundred twenty-one nonagenarians (306 F, 115 M, mean age: 93.1 ± 3.2 years) were evaluated. Adherence to MD was assessed through the Mediterranean Diet Score. Elderly subjects who were in the fourth quartile of the Mediterranean diet score showed significantly higher EPCs than subjects grouped into the other three quartiles. After adjustment for confounders, elderly subjects who were in the highest quartile of adherence to the MD score reported to have EPCs' levels significantly higher than those who reported lower values of adherence to the MD. Furthermore, by analyzing different food categories, it was reported that daily consumption of olive oil and a higher consumption of fruit and vegetables showed higher CPCs CD34⁺ and EPCs CD34⁺/KDR⁺ than subjects with not daily or lower consumption.

CONCLUSION

Our results support the hypothesis that the adherence to MD, as well as a daily consumption of olive oil and fruit and vegetables, characteristics of MD, may protect against the development of endothelial dysfunction through increasing EPCs and CPCs in older age.

Active Stromal Cell-Derived Factor 1α and Endothelial Progenitor Cells are Equally Increased by Alogliptin in Good and Poor Diabetes Control

Background:

It is postulated that the ability of dipeptidyl peptidase-4 inhibitors (DPP-4-i) to increase circulating endothelial progenitor cells (EPCs) may be at least partly mediated by active stromal cell–derived factor 1α (SDF-1α) (a pivotal mediator of stem cell mobilization from the bone marrow). As other DPP-4-i were demonstrated to increase EPC concentrations, in this study, we sought to investigate the ability of the DPP-4-i alogliptin in modifying EPCs and SDF-1α, in patients with good and poor diabetes control.

Methods:

Two groups of diabetic patients on metformin were divided by hemoglobin A_1c (HbA_1c): Group A—those with HbA_1c ≤6.5% (28 patients) and Group B—those with HbA_1c 7.5% to 8.5% (31 patients). Both groups received alogliptin 25 mg/daily for 4 months. At baseline and 4 months later, clinical, laboratory parameters, EPCs, and active SDF-1α were determined.

Results:

After 4-month treatment with alogliptin, either Group A or Group B showed reduced HbA_1c levels and concomitant similar increase in EPCs and active SDF-1α.

Conclusions:

Alogliptin showed significant benefits in increasing EPCs and active SDF-1α either in good or poor diabetes control. The study demonstrated that similar to other DPP-4-i, also alogliptin is able to increase EPC concentrations, suggesting the existence of a class effect mediated by SDF-1α. The extent of increase in EPCs is independent from baseline diabetes control.

Hematopoietic stem/progenitor involvement in retinal microvascular repair during diabetes: Implications for bone marrow rejuvenation

The widespread nature of diabetes affects all organ systems of an individual including the bone marrow. Long-term damage to the cellular and extracellular components of the bone marrow leads to a rapid decline in the bone marrow-hematopoietic stem/progenitor cells (HS/PCs) compartment. This review will highlight the importance of bone marrow microenvironment in maintaining bone marrow HS/PC populations and the contribution of these key populations in microvascular repair during the natural history of diabetes. The autonomic nervous system can initiate and propagate bone marrow dysfunction in diabetes. Systemic pharmacological strategies designed to protect the bone marrow-HS/PC population from diabetes induced-oxidative stress and advanced glycation end product accumulation represent a new approach to target diabetic retinopathy progression. Protecting HS/PCs ensures their participation in vascular repair and reduces the risk of vasogdegeneration occurring in the retina.

Isolation and characterization of human umbilical cord-derived endothelial colony-forming cells

Endothelial colony-forming cells (ECFCs) are a population of endothelial progenitor cells (EPCs) that display robust proliferative potential and vessel-forming capability. Previous studies have demonstrated that a limited number of ECFCs may be obtained from adult bone marrow, peripheral blood and umbilical cord (UC) blood. The present study describes an effective method for isolating ECFCs from human UC. The ECFCs derived from human UC displayed the full properties of EPCs. Analysis of the growth kinetics, cell cycle and colony-forming ability of the isolated human UC-ECFCs indicated that the cells demonstrated properties of stem cells, including relative stability and rapid proliferation in vitro. Gene expression of Fms related tyrosine kinase 1, kinase insert domain receptor, vascular endothelial cadherin, cluster of differentiation (CD)31, CD34, epidermal growth factor homology domains-2, von Willebrand factor and endothelial nitric oxide synthase was assessed by reverse transcription-polymerase chain reaction. The cells were positive for CD34, CD31, CD73, CD105 and vascular endothelial growth factor receptor-2, and negative for CD45, CD90 and human leukocyte antigen-antigen D related protein according to flow cytometry. 1,1'-dioctadecyl-3,3,3',3'-tetra-methyl-indocarbocyanine perchlorate-labeled acetylated low-density lipoprotein and fluorescein isothiocyanate-Ulex europaeus-l were used to verify the identity of the UC-ECFCs. Matrigel was used to investigate tube formation capability. The results demonstrated that the reported technique is a valuable method for isolating human UC-ECFCs, which have potential for use in vascular regeneration.

Interval exercise increases angiogenic cell function in postmenopausal women

INTRODUCTION

Exercise can help to negate the increased cardiovascular disease risk observed in women after the menopausal transition. This study sought to determine whether interval or continuous exercise has differential effects on endothelial function and circulating angiogenic cell (CAC) number and function in postmenopausal women.

METHODS

Fifteen healthy postmenopausal women completed a 30 min acute moderate-intensity continuous (CON) and interval exercise (MOD-INT) session on a cycle ergometer on separate days. Nine participants completed a further single 30 min acute heavy-intensity interval (HEAVY-INT) exercise session. Brachial artery flow-mediated dilation (FMD) was assessed pre-exercise and 15 min post-exercise session. CAC number and colony-forming capacity in vitro were assessed post exercise and compared with resting levels.

RESULTS

FMD and CAC number did not change post exercise regardless of exercise type (p>0.05). However, the number (mean±SD) of colony-forming units (CFUs) increased from visit 1 (12±10 CFUs/well) to post MOD-INT (32±30 CFUs/well) and post HEAVY-INT (38±23 CFUs/well) but not post CON (13±14 CFUs/well).

CONCLUSION

A single session of interval exercise is more effective than a continuous exercise session for increasing the intercellular communication of CACs, regardless of exercise intensity. The enhanced ability of CACs to form colonies may reflect an increased number and/or function of angiogenic T-cells. The repeated exertions to higher work rates during interval exercise may explain this response. Repeated exercise sessions might be required to improve FMD in postmenopausal women.

CD34+ cell count predicts long lasting life in the oldest old

Circulating progenitor cells (CPCs) represent a pool of cells capable of differentiating into mature cells of different organs and systems, promoting tissue maintenance and repair. Among CPCs, CD34+cells (CD34+CPCs) seem to predict outcome in CV disease, also in elderly people. A decline in CD34+CPCs was reported with advancing age. Moreover, aging is associated with a state of chronic inflammation, influencing life expectancy. Our purpose was to investigate a 10-year predictive ability of CD34+CPCs, inflammatory marker levels, classic CV risk factors (CVRFs), and Framingham Risk Score (FRS) in a population of healthy, self-sufficient octogenarians. We found that baseline CD34+CPCs was strongly associated with mortality, showing a significant difference in CD34+CPC numbers between deceased and living patients. Moreover, by dividing our patients into tertiles based on age reached, this difference was more remarkable the higher the age reached. Regressive analyses suggested that the chances of reaching an older age depend on higher CD34+CPCs at baseline and are not significantly affected by inflammatory markers levels, FRS, CVFRs, or HDL-C levels. We found that higher CD34+CPCs predict longer life also in the oldest old, providing additional insights on the predictive role of CD34+CPCs in subjects aged 80 years or more.

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.