Endothelial Progenitor Cells as Biomarkers of Cardiovascular Pathologies: A Narrative Review

Mechanism of disturbed endothelial cell function on angiogenesis following ischemic brain stroke (Review)

The present study focused on the mechanisms of post-ischemic stroke (IS) angiogenesis from the perspective of endothelial cells (ECs) dysfunction. First, it emphasized the importance of hypoxia-inducible factor-1α in the function of ECs under hypoxic conditions, particularly in promoting angiogenesis and improving cerebral blood supply. Secondly, inflammatory cytokines and adhesion factors (for example, selectins, the immunoglobulin superfamily and integrins) influence the function and angiogenesis of ECs through various mechanisms and signaling pathways following IS. In addition, the effects of oxidative stress on ECs function and angiogenesis were explored, along with the potential of antioxidant strategies to improve EC function and promote angiogenesis. Based on these insights, the present study proposed new therapeutic strategies to ameliorate endothelial dysfunction and promote angiogenesis following IS, including small-molecule drugs targeting specific molecules, gene therapy and traditional Chinese medicine treatments. Finally, the importance of translating these laboratory findings into clinical applications was emphasized, alongside the need for advanced imaging techniques to monitor the dynamic processes of post-IS angiogenesis and evaluate the efficacy of novel therapeutic interventions. These explorations aimed at providing a more comprehensive understanding of EC function and the regulatory mechanisms of a deeper understanding of angiogenesis following IS, offering new intervention strategies for IS treatment.

Endothelial progenitor cell-derived conditioned medium mitigates chronic cerebral ischemic injury through macrophage migration inhibitory factor-activated AKT pathway

BACKGROUND

Chronic cerebral ischemia (CCI) is a significant health issue characterized by hypoperfusion due to damage or occlusion of the cerebral or carotid arteries. CCI may lead to progressive cognitive impairment that is considered as a prelude to neurodegenerative diseases, including dementia and Alzheimer's disease (AD). Endothelial progenitor cells (EPCs) have been implicated in vascular repair in ischemic cerebrovascular diseases, primarily by differentiating into endothelial cells (ECs) or through paracrine effects. However, the clinical transplantation of stem cell therapies remains limited. In this study, we investigated the effects of EPC-derived conditioned medium (EPC-CM) on the impaired vasculature and neurological function in a rodent model of CCI and the mechanism involved.

METHODS

EPC-CM was analyzed by cytokine array to identify key factors involved in angiogenesis and cellular senescence. The effects and mechanism of the candidate factors in the EPC-CM were validated in vitro using oxygen-glucose deprivation (OGD)-injured ECs and EPCs. The therapeutic effects of EPC-CM and the identified key factor were further examined in a rat model of CCI, which was induced by bilateral internal carotid artery ligation (BICAL). EPC-CM was administered via intracisternal injection one week post BICAL. The cerebral microvasculature and neurobehavior of the rats were examined three weeks after BICAL.

RESULTS

Macrophage migration inhibitory factor (MIF) was identified as a key factor in the EPC-CM. Recombinant MIF protein promoted angiogenesis and prevented senescence in the injured EPCs and ECs. The effect was similar to that of the EPC-CM. These therapeutic effects were diminished when the EPC-CM was co-treated with MIF-specific antibody (Ab). Additionally, the vascular, motor, and cognitive improvements observed in the BICAL rats treated with EPC-CM were abolished by co-treated with MIF Ab. Furthermore, we found MIF promoted angiogenesis and anti-senescence via activating the AKT pathway. Inhibition of the AKT pathway diminished the protective effects of MIF in the in vitro study.

CONCLUSIONS

We demonstrated that EPC-CM protected the brain from chronic ischemic injury and promoted functional recovery through MIF-mediated AKT pathway. These findings suggest EPC-CM holds potential as a novel cell-free therapeutic approach for treating CCI through the actions of MIF.

Circulating endothelial progenitor cells and inflammatory markers in type 1 diabetes after an acute session of aerobic exercise

Objective

To determine circulating endothelial progenitor cells (EPC) counts and levels of inflammatory markers in individuals with and without type 1 diabetes mellitus (T1DM) in response to an intense aerobic exercise session.

Subjects and methods

In total, 15 adult men with T1DM and 15 healthy individuals underwent a 30-minute aerobic exercise session on a cycle ergometer at 60% of the peak heart rate. The EPC count (CD45dim/CD34+/KDR+), tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) levels were measured before and 60 minutes after the session.

Results

We found no difference within or between groups regarding EPC counts before and after the aerobic exercise: healthy individuals, 0.02% change (95% confidence interval [CI] -0.04%-0.08%); individuals with T1DM, 0.00% (95%CI -0.01%-0.01%). We also found no difference in TNF-α levels before and after exercise in healthy individuals (210.2, interquartile range [IQR] 142.1-401.2 pg/mL and 191.3, IQR 136.4-350.5 pg/mL, respectively) and in patients with T1DM (463.8, IQR 201.4-4306.0 pg/mL and 482.7, IQR 143.8-4304.3 pg/mL, respectively). Similarly, no difference in IL-6 levels was observed before and after exercise in healthy individuals (148.2, IQR 147.5-148.6 pg/mL and 148.2, IQR 147.7-148.6 pg/mL, respectively) and individuals with T1DM (147.2, IQR 145.9-147.7 pg/mL and 147.2, IQR 146.8-147.8 pg/mL, respectively).

Conclusions

Patients with T1DM and healthy controls had comparable EPC responses to aerobic exercise, most likely due to the absence of a chronic inflammatory state.

The effect of empagliflozin on circulating endothelial progenitor cells in patients with diabetes and stable coronary artery disease

BACKGROUND

Diabetes mellitus (DM) is associated with premature atherosclerotic disease, coronary artery disease (CAD) and chronic heart failure (HF), leading to increased morbidity and mortality. Sodium-Glucose Co-transporter 2 Inhibitors (SGLT2i) exhibit cardioprotective benefits beyond glucose lowering, reducing the risk of major cardiovascular events (MACE) and HF hospitalizations in patients with DM and CAD. Endothelial progenitor cells (EPCs) are bone marrow-derived cells involved in vascular repair, mobilized in response to vascular injury. The number and function of circulating EPCs (cEPCs) are negatively affected by cardiovascular risk factors, including DM. This study aimed to examine the response of cEPCs to SGLT2i treatment in DM patients with stable CAD.

METHODS

A prospective single-center study included patients with DM and stable CAD who were started on an SGLT2i (empagliflozin). Peripheral blood samples were collected at baseline, 1 month, and 3 months to evaluate cEPC levels and function by flow cytometry, immunohistochemistry and MTT assays.

RESULTS

Eighteen patients were included in the study (median age 73, (IQR 69, 77) years, 67% male). After 1 month of treatment with empagliflozin, there was no significant change in cEPCs level or function. However, following 3 months of treatment, a significant increase was observed both in cell levels (CD34(+)/VEGFR-2(+): from 0.49% (IQR 0.32, 0.64) to 1.58% (IQR 0.93, 1.82), p = 0.0006; CD133(+)/VEGFR-2(+): from 0.38% (IQR 0.27, 0.6) to 0.82% (IQR 0.7, 1.95), p = 0.0001) and in cell function (from 0.25 CFUs (IQR 0, 0.5) at baseline, to 2 CFUs (IQR 1, 2) at 3 months, p = 0.0012).

CONCLUSIONS

Empagliflozin treatment in patients with DM and stable CAD increases cEPC levels and function, implying a cardioprotective mechanism. These findings highlight the potential of SGLT2i in treating cardiovascular diseases, warranting further research to explore these effects and their long-term implications.

Diagnostic use of circulating cells and sub-cellular bio-particles

In the bloodstream or other physiological fluids, "circulating cells and sub-cellular bio-particles" include many microscopic biological elements such as circulating tumor cells (CTCs), cell-free DNA (cfDNA), exosomes, microRNAs, platelets, immune cells, and proteins are the most well-known and investigated. These structures are crucial biomarkers in healthcare and medical research for the early detection of cancer and other disorders, enabling treatment to commence before the onset of clinical symptoms and enhancing the efficacy of treatments. As the size of these biomarkers to be detected decreases and their numbers in body fluids diminishes, the detection materials, ranging from visual inspection to advanced microscopy techniques, begin to become smaller, more sensitive, faster, and more effective, thanks to developing nanotechnology. This review first defines the circulating cells and subcellular bio-particles with their biological, physical, and mechanical properties and second focuses on their diagnostic importance, including their most recent applications as biomarkers, the biosensors that are utilized to detect them, the present obstacles that must be surmounted, and prospective developments in the domain. As technology advances and biomolecular pathways are deepens, diagnostic tests will become more sensitive, specific, and thorough. Finally, integrating recent advances in the diagnostic use of circulating cells and bioparticles into clinical practice is promising for precision medicine and patient outcomes.

Novel endothelial progenitor cells populations as biomarkers of damage and remission in systemic lupus erythematosus

INTRODUCTION

Endothelial progenitor cells (EPCs) are essential for maintenance of vascular homeostasis and stability, key processes in the pathogenesis of systemic lupus erythematosus (SLE). However, the role and phenotypic characterization of EPCs populations in SLE have not been completely elucidated.

OBJECTIVE

To identify EPCs specific subpopulations in patients with SLE using a novel flow cytometry tool.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SLE and healthy controls (HC). mRNA and surface protein expression were determined by quantitative PCR (qPCR) and flow cytometry. Clusters identification and characterization were performed using tSNE-CUDA dimensionality reduction algorithms.

RESULTS

tSNE-CUDA analysis identified eight different clusters in PBMCs from HC and patients with SLE. Three of these clusters had EPC-like phenotype and the expression was elevated in patients with SLE. Moreover, four SLE-associated subclusters were found mainly expressed in patients with SLE, being only present in patients in remission with SLE and significantly associated with the 2021 Definition of Remission in SLE. Importantly, we also identified specific clusters in SLE patients with organ damage, according to the Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology damage index (SDI). These clusters showed an EPC-like phenotype, but the expression of angiogenic markers was lower compared to HC or patients without organ damage, suggesting an impaired angiogenic function.

CONCLUSION

Our novel approach identified clusters of EPCs in patients with SLE that are associated with remission and damage. Therefore, these clusters might be useful biomarkers to predict disease progression and severity in SLE pathogenesis.

Endothelial progenitor cells for fabrication of engineered vascular units and angiogenesis induction

The promotion of vascularization and angiogenesis in the grafts is a crucial phenomenon in the healing process and tissue engineering. It has been shown that stem cells, especially endothelial progenitor cells (EPCs), can stimulate blood vessel formation inside the engineered hydrogels after being transplanted into the target sites. The incorporation of EPCs into the hydrogel can last the retention time, long-term survival, on-target delivery effects, migration and differentiation into mature endothelial cells. Despite these advantages, further modifications are mandatory to increase the dynamic growth and angiogenesis potential of EPCs in in vitro and in vivo conditions. Chemical modifications of distinct composites with distinct physical properties can yield better regenerative potential and angiogenesis during several pathologies. Here, we aimed to collect recent findings related to the application of EPCs in engineered vascular grafts and/or hydrogels for improving vascularization in the grafts. Data from the present article can help us in the application of EPCs as valid cell sources in the tissue engineering of several ischemic tissues.

OxLDL enhances procoagulant activity of endothelial cells by TMEM16F-mediated phosphatidylserine exposure

Oxidized low-density lipoprotein (oxLDL), a key component in atherosclerosis and hyperlipidemia, is a risk factor for atherothrombosis in dyslipidemia, yet its mechanism is poorly understood. In this study, we used oxLDL-induced human aortic endothelial cells (HAECs) and high-fat diet (HFD)-fed mice as a hyperlipidemia model. Phosphatidylserine (PS) exposure, cytosolic Ca2+, reactive oxygen species (ROS), and lipid peroxidation were measured by flow cytometer. TMEM16F expression was detected by immunofluorescence, western blot, and reverse transcription polymerase chain reaction. Procoagulant activity (PCA) was measured by coagulation time, intrinsic/extrinsic factor Xase, and thrombin generation. We found that oxLDL-induced PS exposure and the corresponding PCA of HAECs were increased significantly compared with control, which could be inhibited over 90% by lactadherin. Importantly, TMEM16F expression in oxLDL-induced HAECs was upregulated by enhanced intracellular Ca2+ concentration, ROS, and lipid peroxidation, which led to PS exposure. Meanwhile, the knockdown of TMEM16F by short hairpin RNA significantly inhibited PS exposure in oxLDL-induced HAECs. Moreover, we observed that HFD-fed mice dramatically increased the progress of thrombus formation and accompanied upregulated TMEM16F expression by thromboelastography analysis, FeCl3-induced carotid artery thrombosis model, and western blot. Collectively, these results demonstrate that TMEM16F-mediated PS exposure may contribute to prothrombotic status under hyperlipidemic conditions, which may serve as a novel therapeutic target for the prevention of thrombosis in hyperlipidemia.

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.

Single-cell transcriptome analysis reveals tumoral microenvironment heterogenicity and hypervascularization in human carotid body tumor

Carotid body tumor (CBT) is a rare neck tumor located at the adventitia of the common carotid artery bifurcation. The prominent pathological features of CBT are high vascularization and abnormal proliferation. However, single-cell transcriptome analysis of the microenvironment composition and molecular complexity in CBT has yet to be performed. In this study, we performed single-cell RNA sequencing (scRNA-seq) analysis on human CBT to define the cells that contribute to hypervascularization and chronic hyperplasia. Unbiased clustering analysis of transcriptional profiles identified 16 distinct cell populations including endothelial cells (ECs), smooth muscle cells (SMCs), neuron cells, macrophage cells, neutrophil cells, and T cells. Within the ECs population, we defined subsets with angiogenic capacity plus clear signs of later endothelial progenitor cells (EPCs) to normal ECs. Two populations of macrophages were detectable in CBT, macrophage1 showed enrichment in hypoxia-inducible factor-1 (HIF-1) and as well as an early EPCs cell-like population expressing CD14 and vascular endothelial growth factor. In addition to HIF-1-related transcriptional protein expression, macrophages1 also display a neovasculogenesis-promoting phenotype. SMCs included three populations showing platelet-derived growth factor receptor beta and vimentin expression, indicative of a cancer-associated fibroblast phenotype. Finally, we identified three types of neuronal cells, including chief cells and sustentacular cells, and elucidated their distinct roles in the pathogenesis of CBT and abnormal proliferation of tumors. Overall, our study provided the first comprehensive characterization of the transcriptional landscape of CBT at scRNA-seq profiles, providing novel insights into the mechanisms underlying its formation.

The effect of exercise on flow-mediated dilation in people with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

Introduction

An increasing number of studies have investigated the effect of exercise on flow-mediated dilation (FMD) in people with type 2 diabetes mellitus (T2DM), while the findings were controversial. The primary aim of this systematic review and meta-analysis was to investigate the effect of exercise on FMD in T2DM patients, and the secondary aim was to investigate the optimal type, frequency, session duration, and weekly time of exercise for T2DM patients.

Methods

Searches were conducted in PubMed, Cochrane Library, Scopus, Web of Science, Embase and EBSCO databases. The Cochrane risk of bias tool (RoB2) in randomized trial and Physiotherapy Evidence Database (PEDro) scale were used to assess the methodological quality of the included studies.

Results

From the 3636 search records initially retrieved, 13 studies met the inclusion criteria. Our meta-analysis revealed that exercise had a significant effect on improving FMD in T2DM patients [WMD, 2.18 (95% CI, 1.78-2.58), p < 0.00001, I2 = 38%], with high-intensity interval training (HIIT) being the most effective intervention type [HIIT, 2.62 (1.42-3.82); p < 0.0001; aerobic exercise, 2.20 (1.29-3.11), p < 0.00001; resistance exercise, 1.91 (0.01-3.82), p = 0.05; multicomponent training, 1.49 (0.15-2.83), p = 0.03]. In addition, a higher frequency [> 3 times, 3.06 (1.94-4.19), p < 0.00001; ≤ 3 times, 2.02 (1.59-2.45), p < 0.00001], a shorter session duration [< 60 min, 3.39 (2.07-4.71), p < 0.00001; ≥ 60 min, 1.86 (1.32-2.40), p < 0.00001], and a shorter weekly time [≤ 180 min, 2.40 (1.63-3.17), p < 0.00001; > 180 min, 2.11 (0.82-3.40), p = 0.001] were associated with larger improvements in FMD.

Conclusion

This meta-analysis provides clinicians with evidence to recommended that T2DM patients participate in exercise, especially HIIT, more than 3 times per week for less than 60 min, with a target of 180 min per week being reached by increasing the frequency of exercise.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023466575.

Upregulation of Anti-Angiogenic miR-106b-3p Correlates Negatively with IGF-1 and Vascular Health Parameters in a Model of Subclinical Cardiovascular Disease: Study with Metformin Therapy

Well-controlled type 1 diabetes mellitus (T1DM) is regarded as a model of subclinical cardiovascular disease (CVD), characterized by inflammation and adverse vascular health. However, the underlying mechanisms are not fully understood. We investigated insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) levels, their correlation to miR-106b-3p expression in a subclinical CVD model, and the cardioprotective effect of metformin. A total of 20 controls and 29 well-controlled T1DM subjects were studied. Plasma IGF-1, IGFBP-3 levels, and miR-106b-3p expression in colony-forming unit-Hills were analyzed and compared with vascular markers. miR-106b-3p was upregulated in T1DM (p < 0.05) and negatively correlated with pro-angiogenic markers CD34+/100-lymphocytes (p < 0.05) and IGF-1 (p < 0.05). IGF-1 was downregulated in T1DM (p < 0.01), which was associated with increased inflammatory markers TNF-α, CRP, and IL-10 and reduced CD34+/100-lymphocytes. IGFBP-3 had no significant results. Metformin had no effect on IGF-1 but significantly reduced miR-106b-3p (p < 0.0001). An Ingenuity Pathway analysis predicted miR-106b-3p to inhibit PDGFA, PIK3CG, GDNF, and ADAMTS13, which activated CVD. Metformin was predicted to be cardioprotective by inhibiting miR-106b-3p. In conclusion: Subclinical CVD is characterized by a cardio-adverse profile of low IGF-1 and upregulated miR-106b-3p. We demonstrated that the cardioprotective effect of metformin may be via downregulation of upregulated miR-106b-3p and its effect on downstream targets.

Endothelial progenitor cells in pregnancy-related diseases

Placental neovascularization plays a crucial role in fetomaternal circulation throughout pregnancy and is dysregulated in several pregnancy-related diseases, including preeclampsia, gestational diabetes mellitus, and fetal growth restriction. Endothelial progenitor cells (EPCs) are a heterogeneous population of cells that differentiate into mature endothelial cells, which influence vascular homeostasis, neovascularization, and endothelial repair. Since their discovery in 1997 by Asahara et al., the role of EPCs in vascular biology has garnered a lot of interest. However, although pregnancy-related conditions are associated with changes in the number and function of EPCs, the reported findings are conflicting. This review discusses the discovery, isolation, and classification of EPCs and highlights discrepancies between current studies. Overviews of how various diseases affect the numbers and functions of EPCs, the role of EPCs as biomarkers of pregnancy disorders, and the potential therapeutic applications involving EPCs are also provided.

The Impact of Modern Anti-Diabetic Treatment on Endothelial Progenitor Cells

Diabetes is one of the leading chronic diseases globally with a significant impact on mortality. This condition is associated with chronic microvascular and macrovascular complications caused by vascular damage. Recently, endothelial progenitor cells (EPCs) raised interest due to their regenerative properties. EPCs are mononuclear cells that are derived from different tissues. Circulating EPCs contribute to regenerating the vessel's intima and restoring vascular function. The ability of EPCs to repair vascular damage depends on their number and functionality. Diabetic patients have a decreased circulating EPC count and impaired EPC function. This may at least partially explain the increased risk of diabetic complications, including the increased cardiovascular risk in these patients. Recent studies have confirmed that many currently available drugs with proven cardiovascular benefits have beneficial effects on EPC count and function. Among these drugs are also medications used to treat different types of diabetes. This manuscript aims to critically review currently available evidence about the ways anti-diabetic treatment affects EPC biology and to provide a broader context considering cardiovascular complications. The therapies that will be discussed include lifestyle adjustments, metformin, sulphonylureas, gut glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor analogs, sodium-glucose transporter 2 inhibitors, and insulin.

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.

Endothelial Progenitor Cells in Autoimmune Disorders

Circulating endothelial progenitor cells (EPCs) were first described in 1997 by Asahara et al. as "putative endothelial cells" from human peripheral blood. The study of endothelial progenitors is also intensifying in several pathologies associated with endothelial damage, including diabetes, myocardial infarction, sepsis, pulmonary arterial hypertension, obstructive bronchopneumopathy and transplantation. EPCs have been studied in several autoimmune diseases with endothelial involvement such as systemic lupus erythematosus, thrombotic thrombocytopenic purpura, antineutrophil cytoplasmic antibodies, vasculitis, rheumatoid arthritis, Goujerot-Sjögren and antiphospholipid syndrome. Factors involved in endothelial damage are due to overexpression of pro-inflammatory cytokines and/or autoantibodies. Management of these pathologies, particularly the long-term use of glucocorticoids and methotrexate, promote atherosclerosis. A lack of standardized assessment of the number and function of EPCs represents a serious challenge for the use of EPCs as prognostic markers of cardiovascular diseases (CVD). The objective of this review was to describe EPCs, their properties and their involvement in several autoimmune diseases.

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.

Carvacrol Improves Vascular Function in Hypertensive Animals by Modulating Endothelial Progenitor Cells

Carvacrol, a phenolic monoterpene, has diverse biological activities, highlighting its antioxidant and antihypertensive capacity. However, there is little evidence demonstrating its influence on vascular regeneration. Therefore, we evaluated the modulation of carvacrol on endothelial repair induced by endothelial progenitor cells (EPC) in hypertension. Twelve-week-old spontaneously hypertensive rats (SHR) were treated with a vehicle, carvacrol (50 or 100 mg/kg/day), or resveratrol (10 mg/kg/day) orally for four weeks. Wistar Kyoto (WKY) rats were used as the normotensive controls. Their systolic blood pressure (SBP) was measured weekly through the tail cuff. The EPCs were isolated from the bone marrow and peripherical circulation and were quantified by flow cytometry. The functionality of the EPC was evaluated after cultivation through the quantification of colony-forming units (CFU), evaluation of eNOS, intracellular detection of reactive oxygen species (ROS), and evaluation of senescence. The superior mesenteric artery was isolated to evaluate the quantification of ROS, CD34, and CD31. Treatment with carvacrol induced EPC migration, increased CFU formation and eNOS expression and activity, and reduced ROS and senescence. In addition, carvacrol reduced vascular ROS and increased CD31 and CD34 expression. This study showed that treatment with carvacrol improved the functionality of EPC, contributing to the reduction of endothelial dysfunction.

Maximal Exercise Improves the Levels of Endothelial Progenitor Cells in Heart Failure Patients

The impact of exercise on the levels of endothelial progenitor cells (EPCs), a marker of endothelial repair and angiogenesis, and circulating endothelial cells (CECs), an indicator of endothelial damage, in heart failure patients is largely unknown. This study aims to evaluate the effects of a single exercise bout on the circulating levels of EPCs and CECs in heart failure patients. Thirteen patients with heart failure underwent a symptom-limited maximal cardiopulmonary exercise test to assess exercise capacity. Before and after exercise testing, blood samples were collected to quantify EPCs and CECs by flow cytometry. The circulating levels of both cells were also compared to the resting levels of 13 volunteers (age-matched group). The maximal exercise bout increased the levels of EPCs by 0.5% [95% Confidence Interval, 0.07 to 0.93%], from 4.2 × 10−3 ± 1.5 × 10−3% to 4.7 × 10−3 ± 1.8 × 10−3% (p = 0.02). No changes were observed in the levels of CECs. At baseline, HF patients presented reduced levels of EPCs compared to the age-matched group (p = 0.03), but the exercise bout enhanced circulating EPCs to a level comparable to the age-matched group (4.7 × 10−3 ± 1.8 × 10−3% vs. 5.4 × 10−3 ± 1.7 × 10−3%, respectively, p = 0.14). An acute bout of exercise improves the potential of endothelial repair and angiogenesis capacity by increasing the circulating levels of EPCs in patients with heart failure.

Statins Show Anti-Atherosclerotic Effects by Improving Endothelial Cell Function in a Kawasaki Disease-like Vasculitis Mouse Model

Kawasaki disease (KD) is an acute inflammatory syndrome of unknown etiology that is complicated by cardiovascular sequelae. Chronic inflammation (vasculitis) due to KD might cause vascular cellular senescence and vascular endothelial cell damage, and is a potential cause of atherosclerosis in young adults. This study examined the effect of KD and HMG-CoA inhibitors (statins) on vascular cellular senescence and vascular endothelial cells. Candida albicans water-soluble fraction (CAWS) was administered intraperitoneally to 5-week-old male apolipoprotein E-deficient (ApoE-) mice to induce KD-like vasculitis. The mice were then divided into three groups: control, CAWS, and CAWS+statin groups. Ten weeks after injection, the mice were sacrificed and whole aortic tissue specimens were collected. Endothelial nitric oxide synthase (eNOS) expression in the ascending aortic intima epithelium was evaluated using immunostaining. In addition, eNOS expression and levels of cellular senescence markers were measured in RNA and proteins extracted from whole aortic tissue. KD-like vasculitis impaired vascular endothelial cells that produce eNOS, which maintains vascular homeostasis, and promoted macrophage infiltration into the tissue. Statins also restored vascular endothelial cell function by promoting eNOS expression. Statins may be used to prevent secondary cardiovascular events during the chronic phase of KD.

RTA-dh404 decreased oxidative stress in mice ischemic limbs and augmented efficacy of therapeutic angiogenesis by intramuscular injection of adipose-derived regenerative cells in the limbs

Although an intramuscular injection of angiogenic cells to ischemic limbs with peripheral artery disease is a therapeutic option to rescue patients by augmenting neovascularization in the limbs, oxidative stress in the limbs may accelerate apoptosis of the injected cells and thereby reduce the therapeutic effect. In this study involving mice with ischemic lower limbs, whether daily oral administration of RTA-dh404, which is an activator of nuclear factor erythroid 2-related factor 2 (Nrf2) with antioxidant activity, could reduce oxidative stress in the limbs and suppress apoptosis of adipose-derived regenerative cells (ADRCs) injected in the limbs, eventually augmenting neovascularization in the limbs, was evaluated. The tissue expression of Nrf2 and concentrations of total antioxidant capacity and superoxide dismutase in the mice ischemic limbs were higher in the RTA-dh404-treated mice than in the control treated mice, and oxidative stress in the limbs of the RTA-dh404 treated mice was decreased. The day after an intramuscular injection of human ADRCs into ischemic lower limbs of immunodeficient mice, the number of apoptotic ADRCs in the ischemic limbs was decreased by approximately 25% in the RTA-dh404-treated mice compared to the control mice. Fourteen days after cell injection, neovascularization and the salvage ratio were increased by approximately 10% and 63%, respectively, in the ischemic limbs in the RTA-dh404-treated mice compared to the control mice. Pretreatment of ischemic limbs by daily oral administration of RTA-dh404 may augment the effect of therapeutic angiogenesis using an intramuscular injection of ADRCs into the ischemic limbs.

Reticulated Platelets and Their Relationship with Endothelial Progenitor Cells during the Acute Phase of ST-Elevation Myocardial Infarction

Introduction: Endothelial progenitor cells (EPC) and reticulated platelets (RP) have central roles in the thrombotic and angiogenetic interactions during ST-elevation myocardial infarction (STEMI). The EPC and RP response in patients with STEMI treated by primary percutaneous intervention (PPCI) has not yet been investigated. Methods: We assessed EPC quantification by the expression of CD133+ and CD34+, and EPC function by the capacity of the cells to form colony-forming units (CFU) and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) during the acute phase of STEMI. These measurements were correlated with RP at baseline and after 24 h following PPCI. Results: Our cohort included 89 consecutive STEMI-diagnosed patients enrolled between December 2018 and July 2021. At baseline, there was a strong positive correlation between reticulated platelet quantity and MTT levels (R = 0.766 and R2 = 0.586, p < 0.001), CD34+ levels (R = 0.602, and R2 = 0.362, p < 0.001); CD133+ levels (R = 0.666 and R2 = 0.443, p < 0.001) and CFU levels (R = 0.437, R2 = 0.191, p < 0.001). The multiple linear regression showed that levels of MTT (adjusted R2 = 0.793; p < 0.001), CD34+ and CD133+ (adjusted R2 = 0.654; p < 0.001 and adjusted R2 = 0.627; p < 0.001, respectively) had strong independent correlations with RP response. At 24 h after PPCI, the correlation between RP quantity and EPC markers was not significant, except for MTT levels (R = 0.465, R2 = 0.216, p < 0.001). Conclusions: In patients with STEMI, higher levels of RP at baseline are significantly correlated with a more potent EPC response. The translational significance of these findings needs further investigation.