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Background: Angiogenesis is essential for repairing critical-sized bone defects. Although adipose-derived stem cell (ADSC)-derived exosomes have been shown to enhance the angiogenesis of endothelial progenitor cells (EPCs), the underlying mechanisms remain unclear. This study aims to explore the effects and mechanisms of ADSC-derived exosomes in enhancing bone repair by promoting EPC angiogenesis. Methods: Transmission electron microscopy, nanoparticle tracking analysis, and Dil reagent kit were employed to identify ADSC-derived exosomes and their internalization by EPCs. Micro-CT analysis, H&E staining, and Masson staining were used to assess bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N), as well as the pathological changes and fibrosis at defect sites. Cell viability, migration, invasion, and tube formation of EPCs were evaluated using CCK-8, wound healing, Transwell, and tube formation assays. Immunohistochemical staining, RT-PCR, and Western blotting were utilized to measure the gene and protein expression of markers such as CD31, VEGFA, OCN, RUNX2, NOTCH1, and DLL4. Gene sequencing and bioinformatics analyses were conducted to identify the most highly expressed miRNA in exosomes, while miRDB and dual-luciferase reporter assays were used to explore the interaction between miR-21-5p and NOTCH1. Results: The ADSC-derived exosomes, averaging 126 nm in diameter, were internalized by EPCs. In vivo, these exosomes promoted new bone formation, increased BMD, BV/TV, Tb.Th, and Tb.N, reduced pathological damage to cranial defect tissues, enhanced vascular and bone tissue regeneration, and upregulated OCN and RUNX2 expression. In vitro, ADSC-derived exosomes enhanced EPC viability, migration, invasion, and tube formation. Both in vivo and in vitro experiments demonstrated that ADSC-derived exosomes upregulated CD31 and VEGFA expression. miR-21-5p, the most highly expressed miRNA in ADSC-derived exosomes, was found to target NOTCH1. Overexpression of miR-21-5p in these exosomes facilitated EPC migration, tube formation, and VEGFA expression while downregulating NOTCH1 and DLL4 expression. Inhibition of miR-21-5p produced opposite effects on EPCs. Conclusions: These findings indicate that miR-21-5p in ADSC-derived exosomes promotes angiogenesis in EPCs to accelerate bone repair by targeting the NOTCH1/DLL4/VEGFA signaling pathway, offering a potential therapeutic strategy for bone defect treatment. [ABSTRACT FROM AUTHOR]

Endothelial progenitor cells (EPCs) are stem cells that can repair injured blood vessels through neovascularisation. This is achieved through secretion of growth factors and endothelial maturation. EPC numbers and function have been studied to determine their diagnostic, prognostic and therapeutic potential in many ischaemic diseases such as stroke. However their activation homing and migration is not definitively understood in stroke patients. In this study, we profiled the non-stroke control group recruited into the Dunhill Medical Trust Endothelial Progenitor Cell Study. Demographic, clinical and plasma levels of angiogenic regulators of participants were analysed to determine if there was any correlation with EPC numbers, subtypes and function. Participants with diabetes had significantly supressed EPC numbers (CD45-CD34 + CD133 + KDR+) and CD34 + KDR + and KDR + EPC subtypes. Male participants had significantly lower EPC numbers compared to female participants and the proliferative capacity of endothelial colony forming cells significantly decreased with increasing participant age. Pro-angiogenic proteins such as granulocyte colony-stimulating factor and stromal cell-derived factor were positively correlated with both undifferentiated and endothelial-committed EPC subtype numbers (CD133+, KDR+, CD34 + CD133+, CD34 + KDR+), whereas anti-angiogenic proteins such as thrombospondin-1 showed a negative correlation with undifferentiated EPC subtypes (CD133+, CD34 + CD133+) but a positive correlation with endothelial-committed EPC subtype numbers (KDR+, CD34 + KDR+). These results show that EPC numbers and subtypes are affected by many factors and larger studies which can analyse and deconvolute the interactions between comorbidities, plasma biomarker levels and EPC are needed. [ABSTRACT FROM AUTHOR]

Antioxidants are essential for mitigating oxidative stress and maintaining vascular health. Endothelial colony-forming cells (ECFCs) are pivotal in endothelial regeneration and angiogenesis and serve as a model to study the diversity of endothelial cells across various organs. This study evaluated the effects of peel, pulp, and seed extracts from Diospyros digyna Jacq. fruit (black persimmon) on human cord blood-derived ECFCs (CB-ECFCs) to determine how the distinct antioxidant profiles of the fruit's different parts influence cellular functions. The extracts did not affect endothelial marker expression, cell proliferation, or nitric oxide production, indicating no cytotoxic or inflammatory effects. However, functional assays revealed that the seed extract significantly enhanced tube formation, increasing closed tubular networks by 1.5-fold. All extracts promoted cell migration, with the seed extract demonstrating the most substantial effect, surpassing even vascular endothelial growth factor (VEGF). Additionally, the seed extract exhibited the strongest reduction in cellular senescence, both before and after oxidative stress induction with H2O2. These findings underscore the potential of black persimmon extracts, especially from the seed, to enhance the regenerative capabilities of CB-ECFCs and reduce cellular senescence without affecting the normal endothelial phenotype. This positions them as promising candidates for developing endothelial cell therapies and advancing vascular regeneration. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Stem cell transplantation has been regarded as a promising therapeutic strategy for myocardial regeneration after myocardial infarction (MI). However, the survival and differentiation of the transplanted stem cells in the hostile ischaemic and inflammatory microenvironment are poor. Recent studies have focused on enhancing the survival and differentiation of the stem cells, while strategies to suppress the senescence of the transplanted stem cells is unknown. Therefore, we investigated the effect of growth differentiation factor 11 (GDF11) on attenuating oxidative stress-induced senescence in the engrafted endothelial progenitor cells (EPCs). Methods: Rat models of oxidative stress were established by hydrogen peroxide conditioning. Oxidative stress-induced senescence was assessed through senescence-associated β-galactosidase expression and lipofuscin accumulation. The effects of GDF11 treatment on senescence and autophagy of EPCs were evaluated 345, while improvement of myocardial regeneration, neovascularization and cardiac function were examined following transplantation of the self-assembling peptide (SAP) loaded EPCs and GDF11 in the rat MI models. Results: Following hydrogen peroxide conditioning, the level of ROS in EPCs decreased significantly upon treatment with GDF11. This resulted in reduction in the senescent cells and lipofuscin particles, as well as the damaged mitochondria and rough endoplasmic reticula. Concurrently, there was a significant increase in LC3-II expression, LC3-positive puncta and the presence of autophagic ultrastructures were increased significantly. The formulated SAP effectively adhered to EPCs and sustained the release of GDF11. Transplantation of SAP-loaded EPCs and GDF11 into the ischaemic abdominal pouch or myocardium resulted in a decreased number of the senescent EPCs. At four weeks after transplantation into the myocardium, neovascularization and myocardial regeneration were enhanced, reverse myocardial remodeling was attenuated, and cardiac function was improved effectively. Conclusions: This study provides novel evidence suggesting that oxidative stress could induce senescence of the transplanted EPCs in the ischemic myocardium. GDF11 demonstrates the ability to mitigate oxidative stress-induced senescence in the transplanted EPCs within the myocardium by activating autophagy. [ABSTRACT FROM AUTHOR]

Endothelial cells (ECs) are a multifaceted component of the vascular system with roles in immunity, maintaining tissue fluid balance, and vascular tone. Dysregulation or dysfunction of ECs can have far-reaching implications, leading pathologies ranging from cardiovascular diseases, such as hypertension and atherosclerosis, ischemia, chronic kidney disease, blood–brain barrier integrity, dementia, and tumor metastasis. Recent advancements in regenerative medicine have highlighted the potential of stem cell-derived ECs, particularly from induced pluripotent stem cells, to treat ischemic tissues, as well as models of vascular integrity. This review summarizes what is known in the generation of ECs with an emphasis on tissue-specific ECs and EC subphenotypes important in the development of targeted cell-based therapies for patient treatment. [ABSTRACT FROM AUTHOR]

Introduction: Poor graft function (PGF), characterized by myelosuppression, represents a significant challenge following allogeneic hematopoietic stem cell transplantation (allo-HSCT) with human cytomegalovirus (HCMV) being established as a risk factor for PGF. However, the underlying mechanism remains unclear. Bone marrow endothelial progenitor cells (BM-EPCs) play an important role in supporting hematopoiesis and their dysfunction contributes to PGF development. We aim to explore the effects of CMV on BM-EPCs and its underlying mechanism. Methods: We investigated the compromised functionality of EPCs derived from individuals diagnosed with HCMV viremia accompanied by PGF, as well as after infected by HCMV AD 169 strain in vitro, characterized by decreased cell proliferation, tube formation, migration and hematopoietic support, and increased apoptosis and secretion of TGF-β1. Results: We demonstrated that HCMV-induced TGF-β1 secretion by BM-EPCs played a dominant role in hematopoiesis suppression in vitro experiment. Moreover, HCMV down-regulates Vitamin D receptor (VDR) and subsequently activates p38 MAPK pathway to promote TGF-β1 secretion by BM-EPCs. Discussion: HCMV could infect BM-EPCs and lead to their dysfunction. The secretion of TGF-β1 by BM-EPCs is enhanced by CMV through the activation of p38 MAPK via a VDR-dependent mechanism, ultimately leading to compromised support for hematopoietic progenitors by BM EPCs, which May significantly contribute to the pathogenesis of PGF following allo-HSCT and provide innovative therapeutic strategies targeting PGF. [ABSTRACT FROM AUTHOR]

Background: Premature infants requiring mechanical ventilation and supplemental oxygen for respiratory support are at increased risk for bronchopulmonary dysplasia (BPD), wherein inflammation have been proposed as a driver of hyperoxia-induced injuries, including persistent loss of endothelial progenitor cells (EPCs), impaired vascularization and eventual alveolar simplification in BPD lungs. However, the underlying mechanisms linking these phenomena remain poorly defined. Methods: We used clodronate liposomes to deplete macrophages in a mouse model of neonatal hyperoxia-induced lung injury to evaluate if EPC loss in BPD lungs could be an effect of macrophage infiltration. We further generated in vitro culture systems initiated with cord blood (CB)-derived CD34+ EPCs and neonatal macrophages either polarized from CB-derived monocytes or isolated from tracheal aspirates of human preterm infants requiring mechanical ventilation and oxygen supplementation, to identify EV-transmitted molecular mechanism that is critical for inhibitory actions of hyperoxic macrophages on EPCs. Results: Initial experiments using mouse model identified the crucial role of macrophage infiltration in eliciting significant reduction of c-Kit+ EPCs in BPD lungs. Further examination of this concept in human system, we found that hyperoxia-exposed neonatal macrophages hamper human CD34+ EPC maintenance and impair endothelial function in the differentiated progeny via the EV transmission of miR-23a-3p. Notably, treatment with antagomiR-23a-3p to silence miR-23a-3p in vivo enhances c-Kit+ EPC maintenance, and increases capillary density, and consequently mitigates simplified alveolarization in BPD lungs. Conclusion: Our findings highlight the importance of pulmonary intercellular communication in the pathophysiology of BPD, by identifying a linkage through vesicle transfer of miR-23a-3p from hyperoxic macrophages to EPCs, and thus demonstrating potential for novel therapeutic target in BPD. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a prevalent yet incurable hematologic malignancy. Despite the proven efficacy of proteasome inhibitors in treating MM, resistance to Bortezomib-based treatments persists in a subset of patients. This case control study explores the potential of circulating endothelial progenitor cells (EPCs) as biomarkers for predicting response to Proteasome Inhibitor based therapy combined with Dexamethasone in MM patients. This study was conducted on 105 MM patients receiving bortezomib plus dexamethasone therapy and 90 healthy individuals as a control group. Utilizing 8-color multi-parameter flow cytometry, we assessed the levels of circulating EPCs, identified through CD34 FITC and CD309 PE markers at diagnosis and after one treatment cycle (4 weeks). Our findings revealed that patients exhibiting poor response to therapy showed significantly higher CD34/CD309 values than those with a good response (p < 0.001). The delineation of response based on CD34/CD309 expression was established with a cutoff ≤ 0.9 for percentage (yielding 100% sensitivity and 94.1% specificity) and ≤ 12.5 for absolute value (also with 100% sensitivity and 94.1% specificity). These results underscore the potential of EPC population levels, as quantified by CD34/CD309, to serve as a predictive biomarker for immunomodulatory treatment in MM patients undergoing Proteasome Inhibitor and Dexamethasone therapy. [ABSTRACT FROM AUTHOR]

Abstract Background Angiogenesis is essential for repairing critical-sized bone defects. Although adipose-derived stem cell (ADSC)-derived exosomes have been shown to enhance the angiogenesis of endothelial progenitor cells (EPCs), the underlying mechanisms remain unclear. This study aims to explore the effects and mechanisms of ADSC-derived exosomes in enhancing bone repair by promoting EPC angiogenesis. Methods Transmission electron microscopy, nanoparticle tracking analysis, and Dil reagent kit were employed to identify ADSC-derived exosomes and their internalization by EPCs. Micro-CT analysis, H&E staining, and Masson staining were used to assess bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N), as well as the pathological changes and fibrosis at defect sites. Cell viability, migration, invasion, and tube formation of EPCs were evaluated using CCK-8, wound healing, Transwell, and tube formation assays. Immunohistochemical staining, RT-PCR, and Western blotting were utilized to measure the gene and protein expression of markers such as CD31, VEGFA, OCN, RUNX2, NOTCH1, and DLL4. Gene sequencing and bioinformatics analyses were conducted to identify the most highly expressed miRNA in exosomes, while miRDB and dual-luciferase reporter assays were used to explore the interaction between miR-21-5p and NOTCH1. Results The ADSC-derived exosomes, averaging 126 nm in diameter, were internalized by EPCs. In vivo, these exosomes promoted new bone formation, increased BMD, BV/TV, Tb.Th, and Tb.N, reduced pathological damage to cranial defect tissues, enhanced vascular and bone tissue regeneration, and upregulated OCN and RUNX2 expression. In vitro, ADSC-derived exosomes enhanced EPC viability, migration, invasion, and tube formation. Both in vivo and in vitro experiments demonstrated that ADSC-derived exosomes upregulated CD31 and VEGFA expression. miR-21-5p, the most highly expressed miRNA in ADSC-derived exosomes, was found to target NOTCH1. Overexpression of miR-21-5p in these exosomes facilitated EPC migration, tube formation, and VEGFA expression while downregulating NOTCH1 and DLL4 expression. Inhibition of miR-21-5p produced opposite effects on EPCs. Conclusions These findings indicate that miR-21-5p in ADSC-derived exosomes promotes angiogenesis in EPCs to accelerate bone repair by targeting the NOTCH1/DLL4/VEGFA signaling pathway, offering a potential therapeutic strategy for bone defect treatment. Graphical Abstract

Abstract 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. Graphical Abstract

Abstract Background Stem cell transplantation has been regarded as a promising therapeutic strategy for myocardial regeneration after myocardial infarction (MI). However, the survival and differentiation of the transplanted stem cells in the hostile ischaemic and inflammatory microenvironment are poor. Recent studies have focused on enhancing the survival and differentiation of the stem cells, while strategies to suppress the senescence of the transplanted stem cells is unknown. Therefore, we investigated the effect of growth differentiation factor 11 (GDF11) on attenuating oxidative stress-induced senescence in the engrafted endothelial progenitor cells (EPCs). Methods Rat models of oxidative stress were established by hydrogen peroxide conditioning. Oxidative stress-induced senescence was assessed through senescence-associated β-galactosidase expression and lipofuscin accumulation. The effects of GDF11 treatment on senescence and autophagy of EPCs were evaluated 345, while improvement of myocardial regeneration, neovascularization and cardiac function were examined following transplantation of the self-assembling peptide (SAP) loaded EPCs and GDF11 in the rat MI models. Results Following hydrogen peroxide conditioning, the level of ROS in EPCs decreased significantly upon treatment with GDF11. This resulted in reduction in the senescent cells and lipofuscin particles, as well as the damaged mitochondria and rough endoplasmic reticula. Concurrently, there was a significant increase in LC3-II expression, LC3-positive puncta and the presence of autophagic ultrastructures were increased significantly. The formulated SAP effectively adhered to EPCs and sustained the release of GDF11. Transplantation of SAP-loaded EPCs and GDF11 into the ischaemic abdominal pouch or myocardium resulted in a decreased number of the senescent EPCs. At four weeks after transplantation into the myocardium, neovascularization and myocardial regeneration were enhanced, reverse myocardial remodeling was attenuated, and cardiac function was improved effectively. Conclusions This study provides novel evidence suggesting that oxidative stress could induce senescence of the transplanted EPCs in the ischemic myocardium. GDF11 demonstrates the ability to mitigate oxidative stress-induced senescence in the transplanted EPCs within the myocardium by activating autophagy.

Abstract 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.

It is relevant to study of angiogenesis mediators and the mobilization of early endothelial progenitor cells (EPС) from bone marrow into the blood in patients with coronary heart disease (CHD), suffering and not suffering from ischemic cardiomyopathy (ICMP).СHD patients: 30 people with ICMP and 22 people without ICMP, 15 healthy donors. The content of early EPС (VEGFR2+CD34+CD14+) was determined in the blood and bone marrow by flow cytofluorometry, the concentration of MSP-1, SDF-1, VEGF-A – by multiplex analysis, of HIF-1α – by ELISA.Тhe content of SDF-1 and HIF-1α in peripheral blood in patients with CHD without cardiomyopathy was higher than in healthy individuals (respectively 60.00 (50.00-80.00) pg/mL and 6.00 (5.00-6.20) ng/mL versus 30.00 (5.00-45.00) pg/mL, p = 0.049 and 4.60 (3.28-5.11) ng/mL, p = 0.049), with ICMP corresponded to the norm. Тhe concentration of SDF-1 in the bone marrow was higher, and the level of HIF-1α was less than their content in the bloodstream, regardless of the presence of ICMP (respectively 130.0 (90.0-170.0) pg/mL, p = 0.005 and 0.97 (0.80-1.11) ng/mL, p < 0.001). The level of MCP-1 in the blood varied within the normal range in patients with CHD of both study groups (190.0 (168.0-215.0) pg/mL), and in the bone marrow was higher only in patients with ICMP (406.5 (265.0-583.0) pg/mL, p = 0.028). Regardless of ICMP presence, the content of VEGF-A in the blood of patients with CHD corresponded to the norm (3.80 (1.00-6.50) pg/mL) and in myeloid tissue. The number of EPC was increased in the blood of patients with CHD without cardiomyopathy (0.70 (0.46-1.23) and 0.19 (0.13-0.32) %, p < 0.001) and corresponded to their number in the bone marrow. And in patients with ICMP, normal values of the indicator were recorded in the blood with the accumulation of EPC in myeloid tissue (0.57 (0.45-0.98) %, p = 0.019).The development of ICMP is associated with the accumulation of early EPC in myeloid tissue due to their increased retention by an excess of MCP-1 in the bone marrow with weak involvement in the bloodstream due to the lack of a surplus of SDF-1 and HIF-1a in the blood.

Abstract Background Premature infants requiring mechanical ventilation and supplemental oxygen for respiratory support are at increased risk for bronchopulmonary dysplasia (BPD), wherein inflammation have been proposed as a driver of hyperoxia-induced injuries, including persistent loss of endothelial progenitor cells (EPCs), impaired vascularization and eventual alveolar simplification in BPD lungs. However, the underlying mechanisms linking these phenomena remain poorly defined. Methods We used clodronate liposomes to deplete macrophages in a mouse model of neonatal hyperoxia-induced lung injury to evaluate if EPC loss in BPD lungs could be an effect of macrophage infiltration. We further generated in vitro culture systems initiated with cord blood (CB)-derived CD34+ EPCs and neonatal macrophages either polarized from CB-derived monocytes or isolated from tracheal aspirates of human preterm infants requiring mechanical ventilation and oxygen supplementation, to identify EV-transmitted molecular mechanism that is critical for inhibitory actions of hyperoxic macrophages on EPCs. Results Initial experiments using mouse model identified the crucial role of macrophage infiltration in eliciting significant reduction of c-Kit+ EPCs in BPD lungs. Further examination of this concept in human system, we found that hyperoxia-exposed neonatal macrophages hamper human CD34+ EPC maintenance and impair endothelial function in the differentiated progeny via the EV transmission of miR-23a-3p. Notably, treatment with antagomiR-23a-3p to silence miR-23a-3p in vivo enhances c-Kit+ EPC maintenance, and increases capillary density, and consequently mitigates simplified alveolarization in BPD lungs. Conclusion Our findings highlight the importance of pulmonary intercellular communication in the pathophysiology of BPD, by identifying a linkage through vesicle transfer of miR-23a-3p from hyperoxic macrophages to EPCs, and thus demonstrating potential for novel therapeutic target in BPD.

Indirect revascularization is one of the main techniques for the treatment of Moyamoya disease. The formation of good collateral circulation is a key measure to improve cerebral blood perfusion and reduce the risk of secondary stroke, and is the main method for evaluating the effect of indirect revascularization. Therefore, how to predict and promote the formation of collateral circulation before and after surgery is important for improving the success rate of indirect revascularization in Moyamoya disease. Previous studies have shown that vascular endothelial growth factor, endothelial progenitor cells, Caveolin-1, and other factors observed in patients with Moyamoya disease may play a key role in the generation of collateral vessels after indirect revascularization through endothelial hyperplasia and smooth muscle migration. In addition, mutations in the genetic factor RNF213 have also been associated with this process. This study summarizes the factors and mechanisms influencing collateral circulation formation after indirect revascularization in Moyamoya disease. [ABSTRACT FROM AUTHOR]

Abstract Endothelial progenitor cells (EPCs) play a crucial role in maintaining vascular health and aiding in the repair of damaged blood vessels. However, the specific impact of EPCs-derived exosomes on vascular endothelial cell injury caused by lipopolysaccharide (LPS) remains inadequately understood. This study aims to explore the potential benefits of EPC-exosomes in mitigating LPS-induced vascular injury and to elucidate the underlying mechanism. Initially, EPCs were isolated from mouse peripheral blood, and their identity was confirmed through flow cytometry and immunocytochemistry. Subsequently, the exosomes derived from EPCs were identified using transmission electron microscopy (TEM) and western blot analysis. A sepsis model was induced by subjecting brain microvascular endothelial cells (BMECs) to LPS-induced injury. Both EPC and their exosomes demonstrated a significant increase in BMECs proliferation, reduced apoptosis, decreased levels of pro-inflammatory factors (TNF-α, IL-6, and caspase-3), and enhanced sprouting and angiogenesis of BMECs. Notable, the Exosomes demonstrated a more pronounced impact on these parameters. Furthermore, both EPCs and Exosomes exhibited significantly increased levels of miR-126a-5p, with the Exosomes showing a more substantial enhancement. These findings suggest that supplementing exosomal miR-126a-5p from EPCs can provide protective effects on BMECs, offering a potential therapeutic option for treating sepsis-induced microvascular endothelial cell injury.

Purpose: Venous leg ulcers (VLUs) are prevalent chronic wounds with limited treatment options. This study aimed to investigate the potential of berberine to enhance endothelial progenitor cell (EPC) function in VLU healing. Methods: Histopathological changes and inflammatory cytokine levels in a deep venous thrombosis (DVT) mouse model were assessed using HE staining and ELISA assays. A luciferase reporter assay was employed to identify the miR-21-3p and RRAGB targeting relationship. EPC proliferation, migration, and tube formation were evaluated through CCK-8, Transwell, and tubule formation assays, while the mTOR pathway and autophagy-related proteins were analyzed by immunofluorescence staining and western blotting. Results: Berberine significantly improved EPC functions, such as proliferation, migration, and tube formation in vitro, and enhanced in vivo EPC-mediated wound healing in a DVT mouse model. Furthermore, miR-21-3p was downregulated in EPCs from VLU patients, and its overexpression improved model EPC functions. Mechanistically, RRAGB, which regulates the mTOR pathway, was identified as a potential miR-21-3p target in EPCs. Overexpression of RRAGB inhibited autophagic activity and impaired EPC function. Conclusion: Berberine shows promise in ameliorating EPC function and promoting wound healing in VLUs. The regulation of the miR-21-3p/RRAGB axis by berberine could offer a promising therapeutic approach for managing VLUs.

Abstract Background Deep vein thrombosis (DVT) is a common vascular surgical disease caused by the coagulation of blood in the deep veins, and predominantly occur in the lower limbs. Endothelial progenitor cells (EPCs) are multi-functional stem cells, which are precursors of vascular endothelial cells. EPCs have gradually evolved into a promising treatment strategy for promoting deep vein thrombus dissolution and recanalization through the stimulation of various physical and chemical factors. Methods In this study, we utilized a mouse DVT model and performed several experiments including qRT-PCR, Western blot, tube formation, wound healing, Transwell assay, immunofluorescence, flow cytometry analysis, and immunoprecipitation to investigate the role of HOXD9 in the function of EPCs cells. The therapeutic effect of EPCs overexpressing HOXD9 on the DVT model and its mechanism were also explored. Results Overexpression of HOXD9 significantly enhanced the angiogenesis and migration abilities of EPCs, while inhibiting cell apoptosis. Additionally, results indicated that HOXD9 specifically targeted the HRD1 promoter region and regulated the downstream PINK1-mediated mitophagy. Interestingly, intravenous injection of EPCs overexpressing HOXD9 into mice promoted thrombus dissolution and recanalization, significantly decreasing venous thrombosis. Conclusions The findings of this study reveal that HOXD9 plays a pivotal role in stimulating vascular formation in endothelial progenitor cells, indicating its potential as a therapeutic target for DVT management. Graphical Abstract

Abstract Cardiovascular diseases (CVDs) have emerged as a predominant threat to human health, surpassing the incidence and mortality rates of neoplastic diseases. Extracellular vesicles (EVs) serve as vital mediators in intercellular communication and material exchange. Endothelial progenitor cells (EPCs), recognized as precursors of vascular endothelial cells (ECs), have garnered considerable attention in recent years due to the potential therapeutic value of their derived extracellular vesicles (EPC-EVs) in the context of CVDs. This comprehensive review systematically explores the origins, characteristics, and functions of EPCs, alongside the classification, properties, biogenesis, and extraction techniques of EVs, with particular emphasis on their protective roles in CVDs. Additionally, we delve into the essential bioactive components of EPC-EVs, including microRNAs, long non-coding RNAs, and proteins, analyzing their beneficial effects in promoting angiogenesis, anti-inflammatory and anti-oxidant activities, anti-fibrosis, anti-apoptosis, and myocardial regeneration. Furthermore, this review comprehensively investigates the therapeutic potential of EPC-EVs across various CVDs, encompassing acute myocardial infarction, myocardial ischemia–reperfusion injury, atherosclerosis, non-ischemic cardiomyopathies, and diabetic cardiovascular disease. Lastly, we summarize the potential challenges associated with the clinical application of EPC-EVs and outline future directions, aiming to offer a valuable resource for both theoretical insights and practical applications of EPC-EVs in managing CVDs.

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

Congenital heart disease (CHD) can be complicated by pulmonary arterial hypertension (PAH). Cardiopulmonary bypass (CPB) for corrective surgery may cause endothelial dysfunction, involving endothelin-1 (ET-1), circulating endothelial cells (CECs), and endothelial progenitor cells (EPCs). These markers can gauge disease severity, but their levels in children's peripheral blood still lack consensus for prognostic value. The aim of our study was to investigate changes in ET-1, cytokines, and the absolute numbers (Ɲ) of CECs and EPCs in children 24 h before and 48 h after CPB surgery to identify high-risk patients of complications. A cohort of 56 children was included: 41 cases with CHD-PAH (22 with high pulmonary flow and 19 with low pulmonary flow) and 15 control cases. We observed that Ɲ-CECs increased in both CHD groups and that Ɲ-EPCs decreased in the immediate post-surgical period, and there was a strong negative correlation between ET-1 and CEC before surgery, along with significant changes in ET-1, IL8, IL6, and CEC levels. Our findings support the understanding of endothelial cell precursors' role in endogenous repair and contribute to knowledge about endothelial dysfunction in CHD. [ABSTRACT FROM AUTHOR]

Endothelial progenitor cells (EPCs) play a crucial role in maintaining vascular health and aiding in the repair of damaged blood vessels. However, the specific impact of EPCs-derived exosomes on vascular endothelial cell injury caused by lipopolysaccharide (LPS) remains inadequately understood. This study aims to explore the potential benefits of EPC-exosomes in mitigating LPS-induced vascular injury and to elucidate the underlying mechanism. Initially, EPCs were isolated from mouse peripheral blood, and their identity was confirmed through flow cytometry and immunocytochemistry. Subsequently, the exosomes derived from EPCs were identified using transmission electron microscopy (TEM) and western blot analysis. A sepsis model was induced by subjecting brain microvascular endothelial cells (BMECs) to LPS-induced injury. Both EPC and their exosomes demonstrated a significant increase in BMECs proliferation, reduced apoptosis, decreased levels of pro-inflammatory factors (TNF-α, IL-6, and caspase-3), and enhanced sprouting and angiogenesis of BMECs. Notable, the Exosomes demonstrated a more pronounced impact on these parameters. Furthermore, both EPCs and Exosomes exhibited significantly increased levels of miR-126a-5p, with the Exosomes showing a more substantial enhancement. These findings suggest that supplementing exosomal miR-126a-5p from EPCs can provide protective effects on BMECs, offering a potential therapeutic option for treating sepsis-induced microvascular endothelial cell injury. [ABSTRACT FROM AUTHOR]

AIM: To explore the effect of microRNA-296-5p (miR-296-5p) on neurological damage after cerebral infarction (CI) and its regulatory relationship with angiotensin-converting enzyme 2 (ACE2) signaling pathway mediated proliferation of endothelial progenitor cell (EPC). METHODS: Serum samples from 70 patients diagnosed with CI and accompanied by neurological damage in our hospital (CI group) and 70 healthy volunteers (healthy group) were selected. The mRNA expression of miR-296-5p, ACE2, and Mas in the serum of both groups were detected by RT-qPCR. The rat model of CI was constructed and SD rats were randomly divided into healthy control group, model control group, sh-miR-296-5p group, and ACE2 overexpression group (OE-ACE2 group). Neurological severity scores (NSS) score was evaluated. The CI status of rats in each group was observed by TTC staining. The mRNA expression of miR-296-5p, ACE2, and Mas in serum of rat was detected by RT-qPCR. EPC were isolated and cultured routinely, and were randomly divided into control group, sh-miR-296-5p group, OE-ACE2 group, OE-miR-296-5p+OE-ACE2 group, and sh-miR-296- 5p+sh-ACE2 group. The viability of EPC was detected by CCK-8. Apoptosis of EPC was detected by flow cytometry. The mRNA expression of miR-296-5p, ACE2, and Mas in EPC was detected by RT-qPCR. The relationship between miR-296-5p and ACE2 was verified by dual luciferase reporter gene assay. RESULTS: (1) Clinical trial: compared with the healthy group, the level of miR-296-5p in serum of CI patients was obviously increased (P<0.05), while the mRNA expression levels of ACE2 and Mas were obviously reduced (P<0.05). (2) Animal experiments: compared with the healthy control group, the NSS score, CI area, the level of miR-296-5p in serum, and the mRNA expression level of Mas in the model control group were obviously increased (P<0.05), while the mRNA expression level of ACE2 was obviously decreased (P<0.05). Compared with the model control group, the NSS score, CI area, the level of miR-296-5p in serum, and the mRNA expression level of Mas in the sh-miR-296-5p group and OE-ACE2 group were obviously reduced (P< 0.05), while the mRNA expression level of the ACE2 was obviously increased (P<0.05). (3) Cell experiment: Com‑ pared with the control group, the A450 and the level of miR-296-5p of EPC cells in the sh-miR-296-5p group and OE-ACE2 group were obviously reduced (P<0.05), the apoptosis rate, the mRNA expression level of ACE2, and Mas were obviously increased (P<0.05). Compared with the sh-miR-296-5p group, the A450 and the level of miR-296-5p in the sh-miR-296-5p+sh-ACE2 group were obviously increased (P<0.05), the apoptosis rate, the mRNA expression level of ACE2, and Mas were obviously reduced (P<0.05). Compared with the OE-ACE2 group, the level of A450 and miR-296-5p in OE-miR-296-5p+OE-ACE2 group were obviously increased (P<0.05), the apoptosis rate, the mRNA expression level of ACE2, and Mas were obviously reduced (P<0.05). CONCLUSION: Knockdown of miR-296-5p may inhibit EPC proliferation by mediating the ACE2 signaling pathway, and alleviate neurological damage after CI. [ABSTRACT FROM AUTHOR]

Sepsis is a potentially fatal syndrome related to severe systemic inflammation developed by infection. Despite different antimicrobial therapies, morbidity and mortality rates remain high. Herbs along with cell therapy have been introduced as a promising option to improve the symptoms of sepsis. The present study aimed to evaluate the therapeutic effect of simultaneous administration of thyme essential oil (TEO) and endothelial progenitor stem cells (EPCs) on lipopolysaccharide (LPS)‐induced sepsis in C57BL/6 mice. Sepsis was induced in C57Bl/6J mice by intraperitoneal injection of LPS, followed 2 h later by an intravenous injection of EPCs or oral administration of TEO or simultaneous administration of TEO and EPCs. After 10 days, the complete blood cell, renal and liver factors, serum levels of inflammatory cytokines, and angiogenic factors were measured. Simultaneous treatment with EPCs and TEO significantly increased the survival of mice with sepsis and modulated the inflammatory response by reducing the serum levels of pro‐inflammatory cytokines. Moreover, this treatment significantly reduced the level of white blood cells and neutrophils and increased the number of red blood cells, the percentage of hematocrit, and hemoglobin. The combination of TEO with EPCs decreased organ injuries and was assessed by lower levels of the liver enzymes alanine aminotransferase and aspartate aminotransferase compared to the sepsis group. Administration of EPCs and TEO also significantly improved angiogenic factors, lung function, and toll‐like receptor 4 expression. EPCs in combination with TEO increase survival in the LPS‐induced sepsis mice model by acting on several targets. Thus, the combination of TEO with EPCs can be a feasible approach for the future clinical treatment and control of sepsis. [ABSTRACT FROM AUTHOR]

Hyperlipidemia is a risk factor for stroke, and worsens neurological outcome after stroke. Endothelial progenitor cells (EPCs), which become dysfunctional in cerebral ischemia, hold capacity to promote revascularization. We investigated the role of dyslipidemia in impairment of EPC-mediated angiogenesis in cerebral ischemic mice. The high fat diet (HFD)-fed mice following by ischemic stroke exhibited increased infarct volumes and neurological severity scores, and poorer angiogenesis. Bone marrow-EPCs treated with palmitic acid (PA) showed impaired functions and inhibited activity of AMP-activated protein kinase (AMPK). Notably, AMPK deficiency aggravated EPC dysfunction, further decreased mitochondrial membrane potential, and increased reactive oxygen species level in EPCs with PA treatment. Furthermore, the expression of fatty acid oxidation (FAO)-related genes was remarkably reduced, and carnitine palmitoyltransferase 1A (CPT1A) protein expression was downregulated in AMPK-deficient EPCs. AMPK deficiency aggravated neurological severity scores and angiogenesis in ischemic brain of HFD-fed mice, accompanied by suppressed protein level of CPT1A. EPC transplantation corrected impaired neurological severity scores and angiogenesis in AMPK-deficient mice. Our findings suggest that AMPK deficiency aggravates poor angiogenesis in ischemic brain by mediating FAO and oxidative stress thereby inducing EPC dysfunction in hyperlipidemic mice. [ABSTRACT FROM AUTHOR]

Chronic diabetes mellitus compromises the vascular system, which causes organ injury, including in the lung. Due to the strong compensatory ability of the lung, patients always exhibit subclinical symptoms. Once sepsis occurs, the degree of lung injury is more severe under hyperglycemic conditions. The α7 nicotinic acetylcholine receptor (α7nAChR) plays an important role in regulating inflammation and metabolism and can improve endothelial progenitor cell (EPC) functions. In the present study, lung injury caused by sepsis was compared between diabetic rats and normal rats. We also examined whether α7nAChR activation combined with EPC transplantation could ameliorate lung injury in diabetic sepsis rats. A type 2 diabetic model was induced in rats via a high-fat diet and streptozotocin. Then, a rat model of septic lung injury was established by intraperitoneal injection combined with endotracheal instillation of LPS. The oxygenation indices, wet-to-dry ratios, and histopathological scores of the lungs were tested after PNU282987 treatment and EPC transplantation. IL-6, IL-8, TNF-α, and IL-10 levels were measured. Caspase-3, Bax, Bcl-2, and phosphorylated NF-κB (p-NF-κB) levels were determined by blotting. Sepsis causes obvious lung injury, which is exacerbated by diabetic conditions. α7nAChR activation and endothelial progenitor cell transplantation reduced lung injury in diabetic sepsis rats, alleviating inflammation and decreasing apoptosis. This treatment was more effective when PNU282987 and endothelial progenitor cells were administered together. p-NF-κB levels decreased following treatment with PNU282987 and EPCs. In conclusion, α7nAChR activation combined with EPC transplantation can alleviate lung injury in diabetic sepsis rats through the NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]

The endothelial-mesenchymal transition (EndMT) of endothelial progenitor cells (EPCs) plays a notable role in pathological vascular remodeling. Emerging evidence indicated that long noncoding RNA-regulator of reprogramming (linc-ROR) can promote epithelial-mesenchymal transition (EMT) in a variety of cancer cells. Nevertheless, the function of linc-ROR in EPC EndMT has not been well elucidated. The present study investigated the effect and possible mechanisms of function of linc-ROR on the EndMT of EPCs. A linc-ROR overexpression lentiviral vector (LV-linc-ROR) or a linc-ROR short hairpin RNA lentiviral vector (LV-shlinc-ROR) was used to up or downregulate linc-ROR expression in EPCs isolated from human umbilical cord blood. Functional experiments demonstrated that LV-linc-ROR promoted the proliferation and migration of EPCs, but inhibited EPC angiogenesis in vitro. In the meantime, reverse transcriptionquantitative PCR and western blotting results showed that the expression of the endothelial cell markers vascular endothelialcadherin and CD31 was decreased, while the expression of the mesenchymal cell markers α-smooth muscle actin and SM22α was increased at both mRNA and protein levels in LV-linc-RORtreated EPCs, indicating that linc-ROR induced EPC EndMT. Mechanistically, the dual-luciferase reporter assay demonstrated that microRNA (miR/miRNA)-145 was a direct target of linc-ROR, and miR-145 binds to the 3'-untranslated region of Smad3. Moreover, LV-shlinc-ROR increased the expression of miR-145, but decreased the expression of Smad3. In conclusion, linc-ROR promotes EPC EndMT, which may be associated with the miR- 145/Smad3 signaling pathway. [ABSTRACT FROM AUTHOR]

Objective To select the cell isolation method, seeding number, and coating conditions for culture flasks to induce and amplify rat bone marrow mononuclear cells （BMMNCs） into endothelial progenitor cells （BM-EPCs）, aiming to establish an efficient, high-yield, and high-purity method for the separation, culture, induction, and amplification of BMEPCs derived from bone marrow. Methods Two-week-old male SD rats were used and euthanized by cervical dislocation, then we isolated the tibia and femur bilaterally to collect bone marrow cell suspensions. We prepared Percoll cell separation solutions at concentrations of 30%, 50%, 60%, and 70%, and separated rat BMMNCs seed cells using the Percoll density gradient centrifugation method, and calculated the ratio of viable cells. The obtained BMMNCs were divided into six groups （1×105, 5×105, 1×106, 2. 5×106, 5×106, and 1×107 cells） and were inoculated in the 25 cm² sterile culture flasks. After 7 days of culture, we observed the number of cell colonies formed in each group under a microscope and calculated the number of colonies formed per 106 cells. Logistic fitting curves were plotted using GraphPad Prism 9. 5 software to determine correla‑ tion based on the R² coefficient, and the P-values were used to include statistically significant seeding numbers. We then used R language to define calculation functions and iteratively found the optimal BMMNCs seeding number based on the known total number of seed cells and the correlation function limitations. Fibronectin （FN） solutions at concentrations of 20 nmol/L, 50 nmol/L, and 100 nmol/L were prepared, and culture flasks were coated for 2, 6, 12, and 24 h with blank solu‑ tions without FN as controls. We inoculated BMMNCs that did not adhere after 48 h into FN-coated culture flasks and cul‑ tured them for 3 days to calculate the number of colonies formed in each group, and determined the optimal FN concentration and coating time. BMMNCs that did not adhere after 48 h were inoculated in the 25 cm² culture flasks, and were induced with EGM-2 complete medium, and we observed the colony formation and induction expansion process under a microscope. BM-EPCs cultured for 14 days were identified for purity using dual-positive staining and flow cytometry. Results The Per‑ coll separation method clearly separated BMMNCs into five layers, with the highest ratio of viable cells between the 30% and 50% Percoll layers. The optimal seeding number for BMMNCs was 2. 5×106 cells. FN solutions at 50 nmol/L for 24 h or 100 nmol/L for 6 h effectively promoted colony formation. After 7 days of cell culture, well-formed cobblestone-like cells were observed, indicating that BMMNCs had been successfully induced into well-formed BM-EPCs. The percentage of Dil-AcLDL/FITC-UEA-1 dual-positive cells was 91. 89%±5. 77%, with CD31+KDR positive rate of 90. 73%±0. 61%, CD14 posi‑ tive rate of 0. 53%±0. 17%, and CD45 positive rate of 0. 77%±0. 34%, indicating that the obtained BM-EPCs were of high purity. Conclusions In the process of inducing and amplifying rat BMMNCs into BM-EPCs, Percoll density gradient cen‑ trifugation can be used to isolate BMMNCs. The optimal cell seeding number for BMMNCs is 2. 5×106 cells, and the culture flask coating conditions are 50 nmol/L FN solution for 24 h or 100 nmol/L FN solution for 6 h. The obtained BM-EPCs through separation, culture, induction, and amplification methods are of good morphology and of high purity. [ABSTRACT FROM AUTHOR]

This research explores the role of microRNA in senescence of human endothelial progenitor cells (EPCs) induced by replication. Hsa‐miR‐134‐5p was found up‐regulated in senescent EPCs where overexpression improved angiogenic activity. Hsa‐miR‐134‐5p, which targeted transforming growth factor β‐activated kinase 1‐binding protein 1 (TAB1) gene, down‐regulated TAB1 protein, and inhibited phosphorylation of p38 mitogen‐activated protein kinase (p38) in hsa‐miR‐134‐5p‐overexpressed senescent EPCs. Treatment with siRNA specific to TAB1 (TAB1si) down‐regulated TAB1 protein and subsequently inhibited p38 activation in senescent EPCs. Treatment with TAB1si and p38 inhibitor, respectively, showed angiogenic improvement. In parallel, transforming growth factor Beta 1 (TGF‐β1) was down‐regulated in hsa‐miR‐134‐5p‐overexpressed senescent EPCs and addition of TGF‐β1 suppressed the angiogenic improvement. Analysis of peripheral blood mononuclear cells (PBMCs) disclosed expression levels of hsa‐miR‐134‐5p altered in adult life, reaching a peak before 65 years, and then falling in advanced age. Calculation of the Framingham risk score showed the score inversely correlates with the hsa‐miR‐134‐5p expression level. In summary, hsa‐miR‐134‐5p is involved in the regulation of senescence‐related change of angiogenic activity via TAB1‐p38 signalling and via TGF‐β1 reduction. Hsa‐miR‐134‐5p has a potential cellular rejuvenation effect in human senescent EPCs. Detection of human PBMC‐derived hsa‐miR‐134‐5p predicts cardiovascular risk. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a metabolic disease with multiple complications, including diabetic cutaneous wounds, which lacks effective treating strategies and severely influences the patients' life. Endothelial progenitor cells (EPCs) are reported to participate in maintaining the normal function of blood vessels, which plays a critical role in diabetic wound healing. TLQP-21 is a VGF-derived peptide with promising therapeutic functions on DM. Herein, the protective effects of TLQP-21 on diabetic cutaneous wound and the underlying mechanism will be investigated. Cutaneous wound model was established in T2DM mice, followed by administering 120 nmol/kg and 240 nmol/kg TLQP-21 once a day for 12 days. Decreased wound closure, reduced number of capillaries and EPCs, declined tube formation function of EPCs, and inactivated PI3K/AKT/eNOS signaling in EPCs were observed in T2DM mice, which were sharply alleviated by TLQP-21. Normal EPCs were extracted from mice and stimulated by high glucose (HG), followed by incubated with TLQP-21 in the presence or absence of LY294002, an inhibitor of PI3K. The declined cell viability, increased apoptotic rate, reduced number of migrated cells, declined migration distance, repressed tube formation function, and inactivated PI3K/AKT/eNOS signaling observed in HG-treated EPCs were markedly reversed by TLQP-21, which were dramatically abolished by the co-culture of LY294002. Collectively, TLQP-21 facilitated diabetic wound healing by inducing angiogenesis through alleviating HG-induced injuries on EPCs. [ABSTRACT FROM AUTHOR]

This comprehensive review explores the multifaceted role of endothelial progenitor cells (EPCs) in vascular diseases, focusing on their involvement in the pathogenesis and their contributions to enhancing the efficacy of endovascular treatments for intracranial aneurysms (IAs). Initially discovered as CD34+ bone marrow-derived cells implicated in angiogenesis, EPCs have been linked to vascular repair, vasculogenesis, and angiogenic microenvironments. The origin and differentiation of EPCs have been subject to debate, challenging the conventional notion of bone marrow origin. Quantification methods, including CD34+ , CD133+ , and various assays, reveal the influence of factors, like age, gender, and comorbidities on EPC levels. Cellular mechanisms highlight the interplay between bone marrow and angiogenic microenvironments, involving growth factors, matrix metalloproteinases, and signaling pathways, such as phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK). In the context of the pathogenesis of IAs, EPCs play a role in maintaining vascular integrity by replacing injured and dysfunctional endothelial cells. Recent research has also suggested the therapeutic potential of EPCs after coil embolization and flow diversion, and this has led the development of device surface modifications aimed to enhance endothelialization. The comprehensive insights underscore the importance of further research on EPCs as both therapeutic targets and biomarkers in IAs. [ABSTRACT FROM AUTHOR]

This study explores the impact of senescence on autocrine C‐C motif chemokine ligand 5 (CCL5) in human endothelial progenitor cell (EPCs), addressing the poorly understood decline in number and function of EPCs during ageing. We examined the effects of replication‐induced senescence on CCL5/CCL5 receptor (CCR5) signalling and angiogenic activity of EPCs in vitro and in vivo. We also explored microRNAs controlling CCL5 secretion in senescent EPCs, its impact on EPC angiogenic activity, and validated our findings in humans. CCL5 secretion and CCR5 levels in senescent EPCs were reduced, leading to attenuated angiogenic activity. CCL5 enhanced EPC proliferation via the CCR5/AKT/P70S6K axis and increased vascular endothelial growth factor (VEGF) secretion. Up‐regulation of miR‐409 in senescent EPCs resulted in decreased CCL5 secretion, inhibiting the angiogenic activity, though these negative effects were counteracted by the addition of CCL5 and VEGF. In a mouse hind limb ischemia model, CCL5 improved the angiogenic activity of senescent EPCs. Analysis involving 62 healthy donors revealed a negative association between CCL5 levels, age and Framingham Risk Score. These findings propose CCL5 as a potential biomarker for detection of EPC senescence and cardiovascular risk assessment, suggesting its therapeutic potential for age‐related cardiovascular disorders. [ABSTRACT FROM AUTHOR]

Background: Deep vein thrombosis (DVT) is a common vascular surgical disease caused by the coagulation of blood in the deep veins, and predominantly occur in the lower limbs. Endothelial progenitor cells (EPCs) are multi-functional stem cells, which are precursors of vascular endothelial cells. EPCs have gradually evolved into a promising treatment strategy for promoting deep vein thrombus dissolution and recanalization through the stimulation of various physical and chemical factors. Methods: In this study, we utilized a mouse DVT model and performed several experiments including qRT-PCR, Western blot, tube formation, wound healing, Transwell assay, immunofluorescence, flow cytometry analysis, and immunoprecipitation to investigate the role of HOXD9 in the function of EPCs cells. The therapeutic effect of EPCs overexpressing HOXD9 on the DVT model and its mechanism were also explored. Results: Overexpression of HOXD9 significantly enhanced the angiogenesis and migration abilities of EPCs, while inhibiting cell apoptosis. Additionally, results indicated that HOXD9 specifically targeted the HRD1 promoter region and regulated the downstream PINK1-mediated mitophagy. Interestingly, intravenous injection of EPCs overexpressing HOXD9 into mice promoted thrombus dissolution and recanalization, significantly decreasing venous thrombosis. Conclusions: The findings of this study reveal that HOXD9 plays a pivotal role in stimulating vascular formation in endothelial progenitor cells, indicating its potential as a therapeutic target for DVT management. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases (CVDs) have emerged as a predominant threat to human health, surpassing the incidence and mortality rates of neoplastic diseases. Extracellular vesicles (EVs) serve as vital mediators in intercellular communication and material exchange. Endothelial progenitor cells (EPCs), recognized as precursors of vascular endothelial cells (ECs), have garnered considerable attention in recent years due to the potential therapeutic value of their derived extracellular vesicles (EPC-EVs) in the context of CVDs. This comprehensive review systematically explores the origins, characteristics, and functions of EPCs, alongside the classification, properties, biogenesis, and extraction techniques of EVs, with particular emphasis on their protective roles in CVDs. Additionally, we delve into the essential bioactive components of EPC-EVs, including microRNAs, long non-coding RNAs, and proteins, analyzing their beneficial effects in promoting angiogenesis, anti-inflammatory and anti-oxidant activities, anti-fibrosis, anti-apoptosis, and myocardial regeneration. Furthermore, this review comprehensively investigates the therapeutic potential of EPC-EVs across various CVDs, encompassing acute myocardial infarction, myocardial ischemia–reperfusion injury, atherosclerosis, non-ischemic cardiomyopathies, and diabetic cardiovascular disease. Lastly, we summarize the potential challenges associated with the clinical application of EPC-EVs and outline future directions, aiming to offer a valuable resource for both theoretical insights and practical applications of EPC-EVs in managing CVDs. [ABSTRACT FROM AUTHOR]

Objectives: Despite mounting evidence demonstrates circulating endothelial progenitor cells (cEPCs) quantitative changes in depression, no study has investigated cEPC functions in major depressive disorder (MDD). We investigated the role of cEPC adhesive and apoptotic functions in MDD. Methods: We recruited 68 patients with MDD and 56 healthy controls (HCs). The depression symptoms, anxiety, psychosomatic symptoms, subjective cognitive dysfunction, quality of life, and functional disability were evaluated using the Hamilton Depression Rating Scale and Montgomery–Åsberg Depression Rating Scale, Hamilton Anxiety Rating Scale, Depression and Somatic Symptoms Scale (DSSS), Perceived Deficits Questionnaire-Depression, 12-Item Short Form Health Survey (SF-12), and Sheehan Disability Scale (SDS), respectively. Working memory and executive function were assessed using a 2-back task and Wisconsin Card Sorting Test (WCST). Inflammatory marker (soluble interleukin-6 receptor, C-reactive protein, and tumor necrosis factor-α receptor-1), cEPC adhesive, and apoptotic levels were measured using in vitro assays. Results: The MDD patients showed significantly lower cEPC adhesive levels than the HCs, and this difference in adhesive function remained statistically significant even after adjusting for inflammatory marker levels. The cEPC adhesion levels were in inverse correlations with commission and omission errors in 2-back task, the percent perseverative response and percent perseverative errors in WCST, and the DSSS and SDS scores, but in positive correlations with SF-12 physical and mental component scores. cEPC apoptotic levels did not differ significantly between the groups. Conclusion: The findings indicate that cEPC adhesive function is diminished in MDD and impacts various aspects of cognitive and psychosocial functions associated with the disorder. [ABSTRACT FROM AUTHOR]

One of cardiovascular diseases that accounts for a high global death rate is atherosclerosis. Apart from the known risk factors, the cause of this disease is uncertain. This disease is triggered by the rupture of atheroma. This condition is associated with oxidative stress, which can trigger endothelial progenitor cells (EPC) dysfunction. One of the causes of oxidative stress is hydrogen peroxide, which triggers deoxyribose nucleotide acid (DNA) damage, which will later trigger ageing in EPC. Sirtuin-1 (SIRT1) is known to be involved in EPC repair, but currently, no studies have attempted to increase SIRT1 expression in vitro. This study aimed to determine the effect of nanoparticles-SIRT1 (NPS1) on the expression of nitric-oxide (NO) and poly (ADP-ribose)-polymerase (PARP) in EPC cell cultures induced by hydrogen peroxide (H2O2). Tests were carried out in vitro using EPC cell cultures to determine the potential of SIRT1 (NPS1) nanoparticles as an ageing inhibitor. The research method used was pure quantitative experimental with a post-test-only control group. The expression of NO and PARP was studied using the flow cytometry method. The data obtained were analysed using parametric one-way ANOVA and post-hoc Tukey-HSD tests with a 95 % confidence interval (p = 0.05). The results showed that administration of SIRT1 nanoparticles was able to increase NO expression in EPC culture cells that induced H2O2 by 14.61 % and could also increase NO levels in normal EPC cells that were only given NPS1 by 38.51 % and was able to reduce PARP expression when compared with the normal group. The NPS1 given was 9.03 % for the NPS1 group and 19.78 % for the NPS1+ H2O2 group. This study concludes that NPS1 added to EPC cells further helps increase cell repair to prevent senescence, through increasing NO and also increasing the performance of PARP. [ABSTRACT FROM AUTHOR]

Articular cartilage regeneration is a major challenge in orthopedic medicine. Endothelial progenitor cells (EPCs) are a promising cell source for regenerative medicine applications. However, their roles and functions in cartilage regeneration are not well understood. Additionally, thermosensitive chitosan hydrogels have been widely used in tissue engineering, but further development of these hydrogels incorporating vascular lineage cells for cartilage repair is insufficient. Thus, this study aimed to characterize the ability of EPCs to undergo endothelial–mesenchymal stem cell transdifferentiation and chondrogenic differentiation and investigate the ability of chondrogenic EPC-seeded thermosensitive chitosan-graft-poly (N-isopropylacrylamide) (CEPC-CSPN) scaffolds to improve healing in a rabbit osteochondral defect (OCD) model. EPCs were isolated and endothelial-to-mesenchymal transition (EndMT) was induced by transforming growth factor-β1 (TGF-β1); these EPCs are subsequently termed transdifferentiated EPCs (tEPCs). The stem cell-like properties and chondrogenic potential of tEPCs were evaluated by a series of in vitro assays. Furthermore, the effect of CEPC-CSPN scaffolds on OCD repair was evaluated. Our in vitro results confirmed that treatment of EPC with TGF-β1 induced EndMT and the acquisition of stem cell-like properties, producing tEPCs. Upon inducing chondrogenic differentiation of tEPCs (CEPCs), the cells exhibited significantly enhanced chondrogenesis and chondrocyte surface markers after 25 days. The TGF-β1-induced differentiation of EPCs is mediated by both the TGF-β/Smad and extracellular signal-regulated kinase (Erk) pathways. The CEPC-CSPN scaffold reconstructed well-integrated translucent cartilage and repaired subchondral bone in vivo, exhibiting regenerative capacity. Collectively, our results suggest that the CEPC-CSPN scaffold induces OCD repair, representing a promising approach to articular cartilage regeneration.

Background Diabetic foot ulcers (DFUs) are a common and serious complication of diabetes, often leading to amputation and decreased quality of life. Current treatment methods have limited success rates, highlighting the need for new approaches. This study investigates the potential of tibial transverse transport (TTT) to promote wound healing in DFUs.Methods To test this hypothesis, the study used New Zealand White rabbits to establish a diabetic model and simulate foot ulcers, followed by the treatment of unilateral TTT or bilateral TTT. The study employed histological analysis, flow cytometry, ELISA, and qPCR to assess the impact of TTT on tissue repair and endothelial progenitor cell (EPC) mobilization and homing, aiming to understand the underlying biological processes in wound healing.Results TTT significantly enhanced wound healing in diabetic rabbit foot ulcers. Specifically, bilateral TTT led to complete wound healing by day 19, faster than the unilateral TTT group, which healed by day 26, and the sham operation group, which nearly healed by day 37. Histological analysis showed improved tissue architecture, collagen deposition, and neovascularization in TTT-treated groups. Furthermore, TTT treatment resulted in a significant increase in VEGFR2 expression and VEGFR2/Tie-2 positive cells, particularly in the bilateral group. These findings were corroborated by qPCR results, which showed increased expression of VEGFA and CXCL12 by TTT. Conclusions: TTT may be a promising treatment for DFUs, significantly enhancing wound healing by stimulating EPC mobilization and homing mediated angiogenesis. This novel approach could substantially improve treatment outcomes for diabetic patients with chronic foot ulcers.

Vasculogenesis, which refers to the development of blood vessels from precursor cells, is a process that occurs predominantly during early embryonic life. It plays a crucial role in the establishment of the primitive vascular network. Vasculogenesis diminishes throughout the fetal vascular remodeling process, giving way to angiogenesis, which becomes the predominant mechanism after birth. At first, the development of the kidney's blood vessels depends on vasculogenesis, and then both vasculogenesis and angiogenesis happen simultaneously. Both processes are necessary for the normal development of the renal vasculature. Although the kidneys are highly vascularized, our understanding of normal kidney vasculogenesis is still incomplete. This lack of knowledge may explain the limited data available on the role of vasculogenesis in the progression and spread of renal cancers. In other types of cancer, researchers have well documented the phenomenon of tumor vasculogenesis. However, there is currently limited and fragmented information about the occurrence of clear-cell renal cell carcinomas (cc-RCC). In this article, we provide a comprehensive review of the current understanding of normal kidney vasculogenesis and vasculogenic pathways in clear cell renal cell carcinoma (cc- RCC).We specifically focus on cellular precursors, growth factors, and the influence of the normal and tumor environments on these processes. It will carefully look at how tumor vasculogenesis might affect the growth andmetastasis of clear cell renal cell carcinoma (cc-RCC), as well as how itmight affect the effectiveness of drugs and the development of therapy resistance. [ABSTRACT FROM AUTHOR]

Background: Indoleamine 2,3-dioxygenase (IDO1) and tryptophan-2,3-dioxygenase (TDO) are the two principals enzymes involved in the catabolization of tryptophan (Trp) into kynurenine (Kyn). Despite their well-established role in the immune escape, their involvement in angiogenesis remains uncertain. We aimed to characterize TDO and IDO1 in human umbilical venular endothelial cells (HUVECs) and human endothelial colony-forming cells (ECFCs). Methods: qRT-PCR and immunofluorescence were used for TDO and IDO1 expression while their activity was measured using ELISA assays. Cell proliferation was examined via MTT tests and in in vitro angiogenesis by capillary morphogenesis. Results: HUVECs and ECFCs expressed TDO and IDO1. Treatment with the selective TDO inhibitor 680C91 significantly impaired HUVEC proliferation and 3D-tube formation in response to VEGF-A, while IDO1 inhibition showed no effect. VEGF-induced mTor phosphorylation and Kyn production were hindered by 680C91. ECFC morphogenesis was also inhibited by 680C91. Co-culturing HUVECs with A375 induced TDO up-regulation in both cell types, whose inhibition reduced MMP9 activity and prevented c-Myc and E2f1 upregulation. Conclusions: HUVECs and ECFCs express the key enzymes of the kynurenine pathway. Significantly, TDO emerges as a pivotal player in in vitro proliferation and capillary morphogenesis, suggesting a potential pathophysiological role in angiogenesis beyond its well-known immunomodulatory effects. [ABSTRACT FROM AUTHOR]

Objective To study changes and correlation of peripheral bold endothelial progenitor cells (EPCs) and serum bFGF, VEGF and MMP-9 in rats with peripheral nerve injury (PNI). Methods Forty-two SD rats were divided into the control group, the PNI 1 d group, the PNI 3 d group, the PNI 5 d group, the PNI 7 d group and the PNI 14 d group according to random number table method, with 7 rats in each group. The sciatic nerve injury model was established in all groups except the control group. In each group, blood samples were collected by living heart puncture at a predetermined time point. Mononuclear cells were extracted by Ficoll density gradient centrifugation. CD34 and CD133 double positive cells were labeled with EPCs, and the number of EPCs in each group was detected by flow cytometry. The contents of bFGF, VEGF and MMP-9 in peripheral blood of each group were detected by enzyme-linked immunosorbent assay, and the correlation between the number of EPCs and bFGF, VEGF and MMP-9 was analyzed. Results Compared with the control group, EPCs in peripheral blood were increased in the PNI 3 d group, the PNI 5 d group and PNI 7 d group. bFGF contents in peripheral blood were increased in the PNI 3 d group, the PNI 5 d group, the PNI 7 d group and the PNI 14 d group, and VEGF contents in peripheral blood were increased in the other groups. The content of MMP-9 in peripheral blood was increased in the PNI 5 d group, the PNI 7 d group and the PNI 14 d group (P＜0.05). The number of EPCs in peripheral blood in the PNI 5 d group and the PNI 7 d group was positively correlated with serum bFGF level (r=0.784 and 0.788, P＜ 0.05) and serum VEGF level (r=0.889 and 0.852, P＜0.05). The number of EPCs in peripheral blood of the PNI 5 d group, the PNI 7 d group and the PNI 14 d group was positively correlated with serum MMP-9 level (r=0.788, 0.852 and 0.873, P＜ 0.05), and it was positively correlated with serum VEGF level (r=0.889 and 0.852, P＜0.05). The number of EPCs in peripheral blood was positively correlated with serum MMP-9 level in the PNI 5 d group, the PNI 7 d group and the PNI 14 d group (r=0.788, 0.852 and 0.873, P＜0.05). Conclusion EPCs, bFGF, VEGF and MMP-9 are involved in the pathophysiological process of blood supply repair after PNI. [ABSTRACT FROM AUTHOR]

Endothelial progenitor cells (EPCs) play a critical role in cardiovascular regeneration. Enhancement of their native properties would be highly beneficial to ensuring the proper functioning of the cardiovascular system. As androgens have a positive effect on the cardiovascular system, we hypothesized that dihydrotestosterone (DHT) could also influence EPC-mediated repair processes. To evaluate this hypothesis, we investigated the effects of DHT on cultured human EPCs' proliferation, viability, morphology, migration, angiogenesis, gene and protein expression, and ability to integrate into cardiac tissue. The results showed that DHT at different concentrations had no cytotoxic effect on EPCs, significantly enhanced the cell proliferation and viability and induces fast, androgen-receptor-dependent formation of capillary-like structures. DHT treatment of EPCs regulated gene expression of androgen receptors and the genes and proteins involved in cell migration and angiogenesis. Importantly, DHT stimulation promoted EPC migration and the cells' ability to adhere and integrate into murine cardiac slices, suggesting it has a role in promoting tissue regeneration. Mass spectrometry analysis further highlighted the impact of DHT on EPCs' functioning. In conclusion, DHT increases the proliferation, migration, and androgen-receptor-dependent angiogenesis of EPCs; enhances the cells' secretion of key factors involved in angiogenesis; and significantly potentiates cellular integration into heart tissue. The data offer support for potential therapeutic applications of DHT in cardiovascular regeneration and repair processes. [ABSTRACT FROM AUTHOR]

Early increase in the level of endothelial progenitor cells (EPCs) in the systemic circulation occurs in patients with septic infection/sepsis. The significance and underlying mechanisms of this response remain unclear. This study investigated the bone marrow EPC response in adult mice with septic infection induced by intravenous injection (i.v.) of Escherichia coli. For in vitro experiments, sorted marrow stem/progenitor cells (SPCs) including lineage(lin)-stem cell factor receptor (c-kit)+stem cell antigen-1 (Sca-1)-, lin-c-kit+, and lin- cells were cultured with or without lipopolysaccharides (LPSs) and recombinant murine vascular endothelial growth factor (VEGF) in the absence and presence of anti-Sca-1 crosslinking antibodies. In a separate set of experiments, marrow lin-c-kit+ cells from green fluorescence protein (GFP)+ mice, i.v. challenged with heatinactivated E. coli or saline for 24 h, were subcutaneously implanted in Matrigel plugs for 5 weeks. Marrow lin-c-kit+ cells from Sca-1 knockout (KO) mice challenged with heat-inactivated E. coli for 24 h were cultured in the Matrigel medium for 8 weeks. The marrow pool of EPCs bearing the lin-c-kit+Sca-1+VEGF receptor 2 (VEGFR2)+ (LKS VEGFR2+) and LKS CD133+VEGFR2+ surface markers expanded rapidly following septic infection, which was supported by both proliferative activation and phenotypic conversion of marrow stem/progenitor cells. Increase in marrow EPCs and their reprogramming for enhancing angiogenic activity correlated with cell-marked upregulation of Sca-1 expression. Sca-1 was coupled with Ras-related C3 botulinum toxin substrate 2 (Rac2) in signaling the marrow EPC response. Septic infection caused a substantial increase in plasma levels of IFN-γ VEGF, G-CSF, and SDF-1. The early increase in circulating EPCs was accompanied by their active homing and incorporation into pulmonary microvasculature. These results demonstrate that the marrow EPC response is a critical component of the host defense system. Sca-1 signaling plays a pivotal role in the regulation of EPC response in mice with septic infection. [ABSTRACT FROM AUTHOR]

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare—through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence—the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development. [ABSTRACT FROM AUTHOR]

Background: CD34 is a transmembrane phosphoglycoprotein and a marker of hematopoietic and nonhematopoietic stem/progenitor cells. In experimental studies, CD34+ cells are rich sources of endothelial progenitor cells and can promote neovascularization and endothelial repair. The potential role of CD34+ cells in stroke patients remains unclear. Aims: We aimed to assess the prognostic effect of circulating CD34+ cell levels on the risk of vascular events and functional prognosis in stroke patients. Patients and methods: In this prospective observational study, patients with ischemic stroke were consecutively enrolled within 1 week of onset and followed up for 1 year. Patients were divided into three groups according to tertiles of the level of circulating CD34+ cells (Tertile 1, <0.51/µL; Tertile 2, 0.51–0.96/µL; and Tertile 3, >0.96/µL). The primary outcome was a composite of major adverse cardiovascular events (MACEs), including nonfatal stroke, nonfatal acute coronary syndrome, major peripheral artery disease, and vascular death. The secondary outcomes included the modified Rankin scale (mRS) scores. Results: A total of 524 patients (mean age, 71.3 years; male, 60.1%) were included. High CD34+ cell levels were associated with younger age (p < 0.001) and low National Institutes of Health Stroke Scale scores at admission (p = 0.010). No significant differences were found in the risk of MACEs among the three groups (annual rates: 15.0%, 13.4%, and 12.6% in Tertiles 1, 2, and 3, respectively; log-rank p = 0.70). However, there were significant differences in the mRS scores at 3 months (median (interquartile range); 2 (1–4), 1 (1–3), and 1 (0–2) in Tertiles 1, 2, and 3, respectively; p = 0.010) and 1 year (3 (1–4), 2 (1–4), and 1 (0–3); p < 0.001) among these groups. After multivariable adjustments, a higher CD34+ cell level was independently associated with good functional outcomes (mRS score of 0–2) at 3 months (adjusted odds ratio (OR), 1.43; 95% confidence interval (CI), 1.01–2.05) and 1 year (adjusted OR, 1.53; 95% CI, 1.09–2.16). Conclusion: Although no correlations were found between circulating CD34+ cell levels and vascular event risk, elevated CD34+ cell levels were associated with favorable functional recovery in stroke patients. Data access statement: Data supporting the findings of this study are available from the corresponding author on reasonable request. Clinical trial registration: The TWMU Stroke Registry is registered at https://upload.umin.ac.jp as UMIN000031913. [ABSTRACT FROM AUTHOR]

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Bone marrow-derived endothelial progenitor cells (EPCs) play a dynamic role in maintaining the structure and function of blood vessels. But how these cells maintain their growth and angiogenic capacity under bone marrow hypoxic niche is still unclear. This study aims to explore the mechanisms from a perspective of cellular metabolism. XFe96 Extracellular Flux Analyzer was used to analyze the metabolic status of EPCs. Gas Chromatography-Mass Spectrometry (GC-MS) was used to trace the carbon movement of 13C-labeled glucose and glutamine under 1 % O 2 (hypoxia) and ∼20 % O 2 (normoxia). Moreover, RNA interference, targeting isocitrate dehydrogenase-1 (IDH1) and IDH2, was used to inhibit the reverse tricarboxylic acid (TCA) cycle and analyze metabolic changes via isotope tracing as well as changes in cell growth and angiogenic potential under hypoxia. The therapeutic potential of EPCs under hypoxia was investigated in the ischemic hindlimb model. Compared with normoxic cells, hypoxic cells showed increased glycolysis and decreased mitochondrial respiration. Isotope metabolic tracing revealed that under hypoxia, the forward TCA cycle was decreased and the reverse TCA cycle was enhanced, mediating the conversion of α-ketoglutarate (α-KG) into isocitrate/citrate, and de novo lipid synthesis was promoted. Downregulation of IDH1 or IDH2 under hypoxia suppressed the reverse TCA cycle, attenuated de novo lipid synthesis (DNL), elevated α-KG levels, and decreased the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor A (VEGFA), eventually inhibiting the growth and angiogenic capacity of EPCs. Importantly, the transplantation of hypoxia-cultured EPCs in a mouse model of limb ischemia promoted new blood vessel regeneration and blood supply recovery in the ischemic area better than the transplantation of normoxia-cultured EPCs. Under hypoxia, the IDH1- and IDH2-mediated reverse TCA cycle promotes glutamine-derived de novo lipogenesis and stabilizes the expression of α-KG and HIF-1α, thereby enhancing the growth and angiogenic capacity of EPCs. [Display omitted] • Hypoxia-induced reverse TCA cycle promotes de novo lipogenesis of bone marrow-derived EPCs. • IDH1 and IDH2 mediate the reverse TCA cycle. • The reverse TCA cycle stabilizes α-KG and sustains HIF-1α levels. • The EPCs cultured under hypoxia have better therapeutic effect on limb ischemia than that under normoxia. [ABSTRACT FROM AUTHOR]

Oxidized low‐density lipoprotein (ox‐LDL) causes dysfunction of endothelial progenitor cells (EPCs), and we recently reported that 14‐3‐3‐η can attenuate the damage triggered by ox‐LDL in EPCs. However, the molecular mechanisms by which 14‐3‐3‐η protects EPCs from the damage caused by ox‐LDL are not fully understood. In this study, we observed that the expression of 14‐3‐3‐η and BCL‐2 were downregulated in ox‐LDL‐treated EPCs. Overexpression of 14‐3‐3‐η in ox‐LDL‐treated EPC significantly increased BCL‐2 level, while knockdown of BCL‐2 reduced 14‐3‐3‐η expression and mitigated the protective effect of 14‐3‐3‐η on EPCs. In addition, we discovered that 14‐3‐3‐η colocalizes and interacts with BCL‐2 in EPCs. Taken together, these data suggest that 14‐3‐3‐η protects EPCs from ox‐LDL‐induced damage by its interaction with BCL‐2. [ABSTRACT FROM AUTHOR]