Endothelial and cardiac progenitor cells for cardiovascular repair: A controversial paradigm in cell therapy

LncRNA H19/miR-107 regulates endothelial progenitor cell pyroptosis and promotes flow recovery of lower extremity ischemia through targeting FADD

BACKGROUND

Peripheral artery disease (PAD) is an ischemic disease with a rising incidence worldwide. The lncRNA H19 (H19) is enriched in endothelial progenitor cells (EPCs), and transplantation of pyroptosis-resistant H19-overexpressed EPCs (oe-H19-EPCs) may promote vasculogenesis and blood flow recovery in PAD, especially with critical limb ischemia (CLI).

METHODS

EPCs isolated from human peripheral blood was characterized using immunofluorescence and flow cytometry. Cell proliferation was determined with CCK8 and EdU assays. Cell migration was assessed by Transwell and wound healing assays. The angiogenic potential was evaluated using tube formation assay. The pyroptosis pathway-related protein in EPCs was detected by western blot. The binding sites of H19 and FADD on miR-107 were analyzed using Luciferase assays. In vivo, oe-H19-EPCs were transplanted into a mouse ischemic limb model, and blood flow was detected by laser Doppler imaging. The transcriptional landscape behind the therapeutic effects of oe-H19-EPCs on ischemic limbs were examined with whole transcriptome sequencing.

RESULTS

Overexpression of H19 in EPCs led to an increase in proliferation, migration, and tube formation abilities. These effects were mediated through pyroptosis pathway, which is regulated by the H19/miR-107/FADD axis. Transplantation of oe-H19-EPCs in a mouse ischemic limb model promoted vasculogenesis and blood flow recovery. Whole transcriptome sequencing indicated significant activation of vasculogenesis pathway in the ischemic limbs following treatment with oe-H19-EPCs.

CONCLUSIONS

Overexpression of H19 increases FADD level by competitively binding to miR-107, leading to enhanced proliferation, migration, vasculogenesis, and inhibition of pyroptosis in EPCs. These effects ultimately promote the recovery of blood flow in CLI.

Endothelial progenitor cell-derived extracellular vesicles: the world of potential prospects for the treatment of cardiovascular diseases

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.

Advancements in tissue engineering for cardiovascular health: a biomedical engineering perspective

Myocardial infarction (MI) stands as a prominent contributor to global cardiovascular disease (CVD) mortality rates. Acute MI (AMI) can result in the loss of a large number of cardiomyocytes (CMs), which the adult heart struggles to replenish due to its limited regenerative capacity. Consequently, this deficit in CMs often precipitates severe complications such as heart failure (HF), with whole heart transplantation remaining the sole definitive treatment option, albeit constrained by inherent limitations. In response to these challenges, the integration of bio-functional materials within cardiac tissue engineering has emerged as a groundbreaking approach with significant potential for cardiac tissue replacement. Bioengineering strategies entail fortifying or substituting biological tissues through the orchestrated interplay of cells, engineering methodologies, and innovative materials. Biomaterial scaffolds, crucial in this paradigm, provide the essential microenvironment conducive to the assembly of functional cardiac tissue by encapsulating contracting cells. Indeed, the field of cardiac tissue engineering has witnessed remarkable strides, largely owing to the application of biomaterial scaffolds. However, inherent complexities persist, necessitating further exploration and innovation. This review delves into the pivotal role of biomaterial scaffolds in cardiac tissue engineering, shedding light on their utilization, challenges encountered, and promising avenues for future advancement. By critically examining the current landscape, we aim to catalyze progress toward more effective solutions for cardiac tissue regeneration and ultimately, improved outcomes for patients grappling with cardiovascular ailments.

Exosomal hsa_circ_0093884 derived from endothelial progenitor cells promotes therapeutic neovascularization via miR-145/SIRT1 pathway

Therapeutic neovascularization is a strategy to promote blood vessel growth and improve blood flow, which is critical to tissue repair and regeneration in ischemic diseases. Here, we investigated the role of endothelial progenitor cell - derived exosomes (EPC-Exos) in therapeutic neovascularization and clarified the mechanism of hsa_circ_0093884 in EPC-Exos mediated neovascularization. Injection of EPC-Exos improved mouse ischemic hindlimb perfusion, promoted angiogenesis in Matrigel plugs and mouse skin wound healing. In vitro coculture with EPC-Exos improved HUVEC proliferation, angiogenic and migration ability, while alleviated hypoxia-induced apoptosis. hsa_circ_0093884 was identified from eleven types of circRNA derived from SIRT1 and proved to be enriched in EPC-Exos. Overexpression of hsa_circ_0093884 in EPC-Exos further enhanced the angiogenic capacity, while knockdown of hsa_circ_0093884 abolished the benefits. Mechanistically, EPC-Exos mediated shuttling of hsa_circ_0093884 induced cytoplasmic sponge of miR-145, thereby releasing repression of SIRT1. In vitro co-transfection indicated silence of miR-145 further strengthened the angiogenic effect of hsa_circ_0093884, while overexpression of miR-145 inhibited hsa_circ_0093884 mediated angiogenesis and abolished the beneficial effect of EPC-Exos. Furthermore, in vivo experiments using endothelial specific SIRT1 conditional knockout mice indicated hsa_circ_0093884 overexpressing EPC-Exos failed to promote therapeutic neovascularization in SIRT1cKO mice. Collectively, our results demonstrated that EPC-Exos promoted therapeutic neovascularization through hsa_circ_0093884/miR-145/SIRT1 axis.

Understanding the intricacies of cellular senescence in atherosclerosis: Mechanisms and therapeutic implications

Cardiovascular disease is currently the largest cause of mortality and disability globally, surpassing communicable diseases, and atherosclerosis is the main contributor to this epidemic. Aging is intimately linked to atherosclerosis development and progression, however, the mechanism of aging in atherosclerosis is not well known. To emphasize the significant research on the involvement of senescent cells in atherosclerosis, we begin by outlining compelling evidence that indicates various types of senescent cells and SASP factors linked to atherosclerotic phenotypes. We subsequently provide a comprehensive summary of the existing knowledge, shedding light on the intricate mechanisms through which cellular senescence contributes to the pathogenesis of atherosclerosis. Further, we cover that senescence can be identified by both structural changes and several senescence-associated biomarkers. Finally, we discuss that preventing accelerated cellular senescence represents an important therapeutic potential, as permanent changes may occur in advanced atherosclerosis. Together, the review summarizes the relationship between cellular senescence and atherosclerosis, and inspects the molecular knowledge, and potential clinical significance of senescent cells in developing senescent-based therapy, thus providing crucial insights into their biology and potential therapeutic exploration.

Therapeutic effect and study of human umbilical cord blood mononuclear cells in patients with ischaemic bowel disease

Ischaemic bowel disease (ICBD) is a group of intestinal ischaemia syndromes caused by various aetiologies of reduced intestinal blood flow or vascular occlusion. ICBD can present as abdominal pain, bloody stool, and diarrhoea. This disease often occurs in middle-aged and elderly individuals with cardiovascular and cerebrovascular diseases. The incidence of ischaemic bowel disease has been increasing for decades, and it is difficult to diagnose, resulting in rapid disease progression and a high mortality rate. Therefore, fully understanding this disease, improving the diagnosis rate of this disease, and finding appropriate treatment methods are urgently needed to improve the condition and prognosis of patients. Umbilical cord blood stem cells are accessible, have weak immunogenicity, and have various biological functions, such as angiogenesis, inflammation and immune regulation. Many studies have confirmed that cord blood stem cells can relieve ischaemia, and these cells have attracted tremendous amounts of attention in regenerative medicine in recent years. In this paper, we discuss the clinical characteristics of ICBD, analyse the characteristics of human umbilical cord blood mononuclear cells (HUCB-MNCs), and use its to treat ischaemic bowel disease. Additionally, we compare the clinical manifestations and related indicators before and after treatment to evaluate the efficacy and safety of these methods.

Efficacy and underlying mechanisms of berberine against lipid metabolic diseases: a review

Lipid-lowering therapy is an important tool for the treatment of lipid metabolic diseases, which are increasing in prevalence. However, the failure of conventional lipid-lowering drugs to achieve the desired efficacy in some patients, and the side-effects of these drug regimens, highlight the urgent need for novel lipid-lowering drugs. The liver and intestine are important in the production and removal of endogenous and exogenous lipids, respectively, and have an important impact on circulating lipid levels. Elevated circulating lipids predisposes an individual to lipid deposition in the vascular wall, affecting vascular function. Berberine (BBR) modulates liver lipid production and clearance by regulating cellular targets such as cluster of differentiation 36 (CD36), acetyl-CoA carboxylase (ACC), microsomal triglyceride transfer protein (MTTP), scavenger receptor class B type 1 (SR-BI), low-density lipoprotein receptor (LDLR), and ATP-binding cassette transporter A1 (ABCA1). It influences intestinal lipid synthesis and metabolism by modulating gut microbiota composition and metabolism. Finally, BBR maintains vascular function by targeting proteins such as endothelial nitric oxide synthase (eNOS) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). This paper elucidates and summarizes the pharmacological mechanisms of berberine in lipid metabolic diseases from a multi-organ (liver, intestine, and vascular system) and multi-target perspective.

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

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

The origin, progress, and application of cell-based cardiac regeneration therapy

Cardiovascular disease (CVD) has become a severe threat to human health, with morbidity and mortality increasing yearly and gradually becoming younger. When the disease progresses to the middle and late stages, the loss of a large number of cardiomyocytes is irreparable to the body itself, and clinical drug therapy and mechanical support therapy cannot reverse the development of the disease. To explore the source of regenerated myocardium in model animals with the ability of heart regeneration through lineage tracing and other methods, and develop a new alternative therapy for CVDs, namely cell therapy. It directly compensates for cardiomyocyte proliferation through adult stem cell differentiation or cell reprogramming, which indirectly promotes cardiomyocyte proliferation through non-cardiomyocyte paracrine, to play a role in heart repair and regeneration. This review comprehensively summarizes the origin of newly generated cardiomyocytes, the research progress of cardiac regeneration based on cell therapy, the opportunity and development of cardiac regeneration in the context of bioengineering, and the clinical application of cell therapy in ischemic diseases.

A tryptophan metabolite prevents depletion of circulating endothelial progenitor cells in systemic low-grade inflammation

Background

Chronic systemic inflammation reduces the bioavailability of circulating endothelial progenitor cells (EPCs). Indoleamine 2,3-dioxygenase 1 (IDO1), a key enzyme of immune tolerance catalyzing the initial step of tryptophan degradation along the so-called l-kynurenine (l-kyn) pathway, that is induced by inflammatory stimuli and exerts anti-inflammatory effects. A specific relationship between IDO1 activity and circulating EPC numbers has not yet been investigated.

Methods

In this study, circulating EPCs were examined in mice treated with low doses of lipopolysaccharide (LPS) to mimic low-grade inflammation. Moreover, the association between IDO1 activity and circulating EPCs was studied in a cohort of 277 patients with variable systemic low-grade inflammation.

Results

Repeated low doses of LPS caused a decrease in circulating EPCs and l-kyn supplementation, mimicking IDO1 activation, significantly increased EPC numbers under homeostatic conditions preventing EPC decline in low-grade endotoxemia. Accordingly, in patients with variable systemic low-grade inflammation, there was a significant interaction between IDO1 activity and high-sensitivity C-reactive protein (hs-CRP) in predicting circulating EPCs, with high hs-CRP associated with significantly lower EPCs at low IDO1 activity but not at high IDO1 activity.

Interpretation

Overall, these findings demonstrate that systemic low-grade inflammation reduces circulating EPCs. However, high IDO1 activity and l-kyn supplementation limit circulating EPC loss in low-grade inflammation.

Advances in lncRNAs from stem cell-derived exosome for the treatment of cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of mortality globally. Benefiting from the advantages of early diagnosis and precision medicine, stem cell-based therapies have emerged as promising treatment options for CVDs. However, autologous or allogeneic stem cell transplantation imposes a potential risk of immunological rejection, infusion toxicity, and oncogenesis. Fortunately, exosome can override these limitations. Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) in exosome from stem cell paracrine factors play critical roles in stem cell therapy and participate in numerous regulatory processes, including transcriptional silencing, transcriptional activation, chromosome modification, and intranuclear transport. Accordingly, lncRNAs can treat CVDs by directly acting on specific signaling pathways. This mini review systematically summarizes the key regulatory actions of lncRNAs from different stem cells on myocardial aging and apoptosis, ischemia-reperfusion injury, retinopathy, atherosclerosis, and hypertension. In addition, the current challenges and future prospects of lncRNAs treatment for CVDs are discussed.

Human umbilical cord blood mononuclear cells transplantation for perinatal brain injury

Perinatal brain injury is a leading cause of death and disability in children. Hypoxic-ischemic encephalopathy in full term infants, and white matter injury in premature infants are most known brain injury in perinatal period. Human umbilical cord blood mononuclear cells contain hematopoietic stem cells, mesenchymal stem cells, endothelial progenitor cells, lymphocytes, monocytes, and so on. Human umbilical cord blood mononuclear cells have many biological functions, such as nerve and vascular regeneration, anti-apoptosis, anti-inflammation, and immune regulation. Human umbilical cord blood mononuclear cells transplantation has achieved significant efficacy and safety in animal and clinical trials for the treatment of perinatal brain injury. We will review human umbilical cord blood mononuclear cells transplantation for perinatal brain injury in this review.

Recent advances of natural and bioengineered extracellular vesicles and their application in vascular regeneration

The progression of cardiovascular diseases such as atherosclerosis and myocardial infarction leads to serious vascular injury, highlighting the urgent need for targeted regenerative therapy. Extracellular vesicles (EVs) composed of a lipid bilayer containing nuclear and cytosolic materials are relevant to the progression of cardiovascular diseases. Moreover, EVs can deliver bioactive cargo in pathological cardiovascular and regulate the biological function of recipient cells, such as inflammation, proliferation, angiogenesis and polarization. However, because the targeting and bioactivity of natural EVs are subject to several limitations, bioengineered EVs have achieved wide advancements in biomedicine. Bioengineered EVs involve three main ways to acquire including (i) modification of the EVs after isolation; (ii) modification of producer cells before EVs’ isolation; (iii) synthesize EVs using natural or modified cell membranes, and encapsulating drugs or bioactive molecules into EVs. In this review, we first summarize the cardiovascular injury-related disease and describe the role of different cells and EVs in vascular regeneration. We also discuss the application of bioengineered EVs from different producer cells to cardiovascular diseases. Finally, we summarize the surface modification on EVs which can specifically target abnormal cells in injured vascular.

Endothelial progenitor cells overexpressing Grb2-associated binder 1 for in vitro-constructed tissue-engineered heart valves

Aim    Endothelial progenitor cells (EPCs) play important roles in heart valve replacement surgery. Up-regulation of Grb2‑associated binder 1 (Gab1) promotes hepatocyte growth factor (HGF) - induced endothelial progenitor cell proliferation and migration. This study aimed to investigate the effects of up-regulation of Gab1 in hepatocyte growth factor-induced EPCs in tissue-engineered heart valves (TEHV).Material and methods    Fresh porcine aortic valves were placed in 1 % Triton X-100 and trypsin buffer for decellularization. EPCs in the control group were cultured normally, whereas those in the experimental group were both HGF stimulated and transfected with adenovirus containing the Gab1 gene. Cells in the two groups were seeded onto the decellularized valve scaffolds and cultured for 3 or 7 days. TEHV were analyzed by HE and AB-PAS staining.Results    By day 3, the experimental group had formed confluent endothelial monolayers on top of the decellularized valves, on the basis of by HE staining and AB-PAS staining. One week later, the control group showed a imperfect endothelial layer.Conclusion    HGF-induced EPCs overexpressing Gab1 can endothelialize the decellularized matrix and create functional TEHV, which may then be preconditioned in a bioreactor before clinical implantation.

The potential role of circulating exosomes in protecting myocardial injury in acute myocardial infarction via regulating miR-190a-3p/CXCR4/CXCL12 pathway

Exosomes of different origins have been found to be protective against ischemic-induced myocardial injury. This study examined the protective effects of circulating exosomes in the mice model of acute myocardial infarction (AMI) and explored the underlying molecular mechanisms. The effects of exosomes on myocardial injury were assessed in the AMI mice model. The in vivo studies showed that circulating exosomes reduced the infarcted size, improved the morphology of heart tissues and also reduced apoptosis of the heart tissues. In addition, the model mice showed an increase in the CD34 + /VEGFR2 + cell population and CD31, CXCR4 and CXCL12 expression after exosomes treatment. MiR-190a-3p was significantly down-regulated in the exosomes derived from the culture medium of hypoxia-treated human cardiomyocytes (HCMs). Further analysis revealed that miR-190a-3p could physically interact with CXCR4/CXCL12 by targeting the respective 3'UTRs. These exosomes could up-regulated CXCR4 and CXCL12 expression in the EPCs; in addition, miR-190a-3p mimics repressed CXCR4/CXCL12 expression in EPCs, while its inhibitor had opposite effects. The in vitro functional assays showed that miR-190a-3p overexpression suppressed the cell viability, proliferation, migration, adhesion and tube formation of EPCs; while miR-190a-3p inhibitor had the opposite effects; exosomes derived from the culture medium of hypoxia-treated HCMs exhibited similar actions of miR-190a-3p inhibitor. Moreover, miR-190a-3p was down-regulated in exosomes from serum in the AMI group when compared to that from sham group. Treatment with exosomes from serum in the AMI group promoted cell proliferation, migration, adhesion and tube formation of EPCs when compared to that in the sham group. More importantly, IT1t attenuated the enhanced effects of miR-190a-3p inhibition on EPC proliferation, migration, adhesion and tube formation. In conclusion, circulating exosomes exerted protective effects on myocardial injury in the AMI mice model, and down-regulation of miR-190a-3p in the circulating exosomes may exert protective effects against myocardial injury. Hypoxia induced the downregulation of miR-190a-3p in the culture medium of HCMs, and the mechanistic investigations indicated that exosomes of hypoxia-conditioned HCM culture medium promoted the cell viability, proliferation, migration, adhesion and tube formation of EPCs via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

TLR4-SIRT3 Mechanism Modulates Mitochondrial and Redox Homeostasis and Promotes EPCs Recruitment and Survival

The low survival rate of endothelial progenitor cells (EPCs) in vivo which are susceptible to adverse microenvironments including inflammation and oxidative stress has become one primary challenge of EPCs transplantation for regenerative therapy. Recent studies reported functional expression of toll-like receptor (TLR) 4 on EPCs and dose-dependent effects of lipopolysaccharide (LPS) on cellular oxidative stress and angiogenic properties. However, the involved mechanism has not yet been elucidated well, and the influence of TLR4 signaling on EPCs survival and function in vivo is unknown. In the present study, we observed the effects of LPS and TLR4/SIRT3 on EPCs mitochondrial permeability and intracellular mitochondrial superoxide. We employed the monocrotaline-induced pulmonary arteriolar injury model to observe the effects of TLR4/SIRT3 on the recruitment and survival of transplanted EPCs. We found the destructive effects of 10 μg/mL LPS on mitochondrial homeostasis, and cellular viability was mediated by TLR4/SIRT3 signals at least partially, and the TLR4 mediates the early-stage recruitment of transplanted EPCs in pulmonary arteriolar inflammation injury; however, SIRT3 has more contribution to the survival of incorporated EPCs and ameliorated arteriolar remodeling in lung vascular tissue. The study provides insights for the critical role of TLR4/SIRT3 in LPS-induced oxidative stress and mitochondrial disorder in EPCs in vitro and in vivo. The TLR4/SIRT3 signaling is important for EPCs resistance against inflammation and oxidative stress and may represent a new manipulating target for developing efficient cell therapy strategy.

Targeted trapping of endogenous endothelial progenitor cells for myocardial ischemic injury repair through neutrophil-mediated SPIO nanoparticle-conjugated CD34 antibody delivery and imaging

Endothelia progenitor cell (EPC)-based revascularization therapies have shown promise for the treatment of myocardial ischemic injury. However, applications and efficacy are limited by the relatively inefficient recruitment of endogenous EPCs to the ischemic area, while implantation of exogenous EPCs carries the risk of tumorigenicity. In this study, we developed a therapeutic protocol that relies on the capacity of neutrophils (NEs) to target lesions and release preloaded EPC-binding molecules for high efficiency capture. Neutrophils were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface marker CD34 (SPIO-antiCD34/NEs), and the therapeutic efficacy in ischemic mouse heart following SPIO-antiCD34/NEs injection was monitored by SPIO-enhanced magnetic resonance imaging (MRI). These SPIO-antiCD34/NEs exhibited unimpaired cell viability, superoxide generation, and chemotaxis in vitro as well as satisfactory biocompatibility in vivo. In a mouse model of acute myocardial infarction (MI), SPIO-antiCD34 accumulation could be observed 0.5 h after intravenous injection of SPIO-antiCD34/NEs. Moreover, the degree of CD133⁺ EPC accumulation at MI sites was three-fold higher than in control MI model mice, while ensuing microvessel density was roughly two-fold higher than controls and left ventricular ejection fraction was > 50%. Therapeutic cell biodistribution, MI site targeting, and treatment effects were confirmed by SPIO-enhanced MRI. This study offers a new strategy to improve the endogenous EPC-based myocardial ischemic injury repair through NEs mediated SPIO nanoparticle conjugated CD34 antibody delivery and imaging. STATEMENT OF SIGNIFICANCE: The efficacy of endogenous endothelial progenitor cell (EPC)-based cardiovascular repair therapy for ischemic heart damage is limited by relatively low EPC accumulation at the target site. We have developed a method to improve EPC capture by exploiting the strong targeting ability of neutrophils (NEs) to ischemic inflammatory foci and the capacity of these treated cells to release of preloaded cargo with EPC-binding affinity. Briefly, NEs were loaded with superparamagnetic iron oxide nanoparticles conjugated to an antibody against the EPC surface protein CD34 (SPIO-antiCD34). Thus, we explored sites targeting with nanocomposites cargo for non-invasive EPCs interception and therapy tracking. We demonstrate that SPIO-antiCD34 released from NEs can effectively capture endogenous EPCs and thereby promote heart revascularization and functional recovery in mice. Moreover, the entire process can be monitored by SPIO-enhanced magnetic resonance imaging including therapeutic cell biodistribution, myocardial infarction site targeting, and tissue repair.

Circulating biomarkers for management of cancer therapeutics related cardiac dysfunction

Cancer therapeutics related cardiac dysfunction (CTRCD) has emerged as a major cause of morbidity and mortality in cancer survivors. Effective clinical management of CTRCD is impeded by a lack of sensitive diagnostic and prognostic strategies. Circulating molecular markers could potentially address this need as they are often indicative of cardiac stress before cardiac damage can be detected clinically. A growing understanding of the underlying physiological mechanisms for CTRCD has inspired research efforts to identify novel pathophysiologically-relevant biomarkers that may also guide development of cardio-protective therapeutic approaches. The purpose of this review is to evaluate current circulating biomarkers of cardiac stress and their potential role in diagnosis and management of CTRCD. We also discuss some emerging avenues for CTRCD-focused biomarker investigations.

Endothelial Progenitor Cells in Coronary Artery Disease: From Bench to Bedside

Endothelial progenitor cells (EPCs) are a heterogeneous group of cells present in peripheral blood at various stages of endothelial differentiation. EPCs have been extensively investigated in patients with coronary artery disease (CAD), with controversial findings both on their role in atherosclerosis progression and in the process of neointimal growth after a percutaneous coronary intervention (PCI). Despite nearly 2 decades of experimental and clinical investigations, however, the significance of EPCs in clinical practice remains unclear and poorly understood. This review provides an update on the role of EPCs in the most common clinical scenarios that are experienced by cardiologists managing patients with CAD. We here summarize the main findings on the association of EPCs with cardiovascular risk factors, coronary atherosclerosis, and myocardial ischemia. We then discuss the potential effects of EPCs in post-PCI in-stent restenosis, as well as most recent findings with EPC-coated stents. Based on the mounting evidence of the relationship between levels of EPCs and several different adverse cardiovascular events, EPCs are emerging as novel predictive biomarkers of long-term outcomes in patients with CAD.

Endothelial colony-forming cell-derived exosomal miR-21-5p regulates autophagic flux to promote vascular endothelial repair by inhibiting SIPL1A2 in atherosclerosis

Background

Percutaneous transluminal coronary angioplasty (PTCA) represents an efficient therapeutic method for atherosclerosis but conveys a risk of causing restenosis. Endothelial colony-forming cell-derived exosomes (ECFC-exosomes) are important mediators during vascular repair. This study aimed to investigate the therapeutic effects of ECFC-exosomes in a rat model of atherosclerosis and to explore the molecular mechanisms underlying the ECFC-exosome-mediated effects on ox-LDL-induced endothelial injury.

Methods

The effect of ECFC-exosome-mediated autophagy on ox-LDL-induced human microvascular endothelial cell (HMEC) injury was examined by cell counting kit-8 assay, scratch wound assay, tube formation assay, western blot and the Ad-mCherry-GFP-LC3B system. RNA-sequencing assays, bioinformatic analysis and dual-luciferase reporter assays were performed to confirm the interaction between the miR-21-5p abundance of ECFC-exosomes and SIPA1L2 in HMECs. The role and underlying mechanism of ECFC-exosomes in endothelial repair were explored using a high-fat diet combined with balloon injury to establish an atherosclerotic rat model of vascular injury. Evans blue staining, haematoxylin and eosin staining and western blotting were used to evaluate vascular injury.

Results

ECFC-exosomes were incorporated into HMECs and promoted HMEC proliferation, migration and tube formation by repairing autophagic flux and enhancing autophagic activity. Subsequently, we demonstrated that miR-21-5p, which is abundant in ECFC-exosomes, binds to the 3’ untranslated region of SIPA1L2 to inhibit its expression, and knockout of miR-21-5p in ECFC-exosomes reversed ECFC-exosome-decreased SIPA1L2 expression in ox-LDL-induced HMEC injury. Knockdown of SIPA1L2 repaired autophagic flux and enhanced autophagic activity to promote cell proliferation in ox-LDL-treated HMECs. ECFC-exosome treatment attenuated vascular endothelial injury, regulated lipid balance and activated autophagy in an atherogenic rat model of vascular injury, whereas these effects were eliminated with ECFC-exosomes with knockdown of miR-21-5p.

Conclusions

Our study demonstrated that ECFC-exosomes protect against atherosclerosis- or PTCA-induced vascular injury by rescuing autophagic flux and inhibiting SIAP1L2 expression through delivery of miR-21-5p.

Vascular Stem/Progenitor Cells in Vessel Injury and Repair

Vascular repair upon vessel injury is essential for the maintenance of arterial homeostasis and function. Stem/progenitor cells were demonstrated to play a crucial role in regeneration and replenishment of damaged vascular cells during vascular repair. Previous studies revealed that myeloid stem/progenitor cells were the main sources of tissue regeneration after vascular injury. However, accumulating evidences from developing lineage tracing studies indicate that various populations of vessel-resident stem/progenitor cells play specific roles in different process of vessel injury and repair. In response to shear stress, inflammation, or other risk factors-induced vascular injury, these vascular stem/progenitor cells can be activated and consequently differentiate into different types of vascular wall cells to participate in vascular repair. In this review, mechanisms that contribute to stem/progenitor cell differentiation and vascular repair are described. Targeting these mechanisms has potential to improve outcome of diseases that are characterized by vascular injury, such as atherosclerosis, hypertension, restenosis, and aortic aneurysm/dissection. Future studies on potential stem cell-based therapy are also highlighted.

Tempol Preserves Endothelial Progenitor Cells in Male Mice with Ambient Fine Particulate Matter Exposure

Ambient fine particulate matter (PM) exposure associates with an increased risk of cardiovascular diseases (CVDs). Major sex differences between males and females exist in epidemiology, pathophysiology, and outcome of CVDs. Endothelial progenitor cells (EPCs) play a vital role in the development and progression of CVDs. PM exposure-induced reduction of EPCs is observed in male, not female, mice with increased reactive oxygen species (ROS) production and oxidative stress. The lung is considered an important source of ROS in mice with PM exposure. The aim of the present study was to investigate the sex differences in pulmonary superoxide dismutase (SOD) expression and ROS production, and to test the effect of SOD mimic Tempol on the populations of EPCs in mice with PM exposure. Both male and female C57BL/6 mice (8–10 weeks) were exposed to intranasal PM or vehicle for 6 weeks. Flow cytometry analysis demonstrated that PM exposure significantly decreased the levels of EPCs (CD34⁺/CD133⁺) in both blood and bone marrow with increased ROS production in males, but not in females. ELISA analysis showed higher levels of serum IL-6 and IL-1βin males than in females. Pulmonary expression of the antioxidant enzyme SOD1 was significantly decreased in males after PM exposure, but not in females. Administration of the SOD mimic Tempol in male mice with PM exposure attenuated the production of ROS and inflammatory cytokines, and preserved EPC levels. These data indicated that PM exposure-induced reduction of EPC population in male mice may be due to decreased expression of pulmonary SOD1 in male mice.

Paracrine mechanisms of endothelial progenitor cells in vascular repair

Endothelial progenitor cells (EPCs) play an important role in repairing damaged blood vessels and promoting neovascularization. However, the specific mechanism of EPCs promoting vascular repair is still unclear. Currently, there are two different views on the repair of damaged vessels by EPCs, one is that EPCs can directly differentiate into endothelial cells (ECs) and integrate into injured vessels, the other is that EPCs act on cells and blood vessels by releasing paracrine substances. But more evidence now supports the latter. Therefore, the paracrine mechanisms of EPCs are worth further study. This review describes the substances secreted by EPCs, some applications based on paracrine effects of EPCs, and the studies of paracrine mechanisms in cardiovascular diseases--all of these are to support the view that EPCs repair blood vessels through paracrine effects rather than integrating directly into damaged vessels.

Effects of Berberine on Atherosclerosis

Atherosclerosis is an epidemic across the globe[A1], and its morbidity and mortality remain high, involving various complications and poor prognoses. In atherosclerosis, endothelial cells (ECs) dysfunction, vascular smooth muscle cells (VSMCs) migration and proliferation, foam cell formation, and inflammatory cell recruitment contribute to disease progression. Vascular stem cells (VSCs) also play a critical role in the cardiovascular system. Important data showed that the simultaneous increase of proliferation and apoptosis of VSMCs is the main cause of graft vein stenosis, suggesting that inhibition of VSMCs proliferation and apoptosis simultaneously is an important strategy for the treatment of atherosclerotic stenosis. Complementary and alternative medicine use among patients with cardiovascular disease (CVD) is growing. Berberine is an extract of Chinese traditional herbs that is known for its antimicrobial and anti-inflammatory effects in the digestive system. Its underlying anti-CVD mechanisms are currently attracting interest, and its pharmacological actions, such as antioxidation, regulation of neurotransmitters and enzymes, and cholesterol-lowering effects, have been substantiated. Recent studying found that berberine could inhibit both the proliferation and apoptosis of VSMCs induced by mechanical stretch stress simultaneously, which suggests that berberine might be an excellent drug to treat atherosclerosis. This review will focus on the recent progress of the effect of berberine on vascular cells, especially VSMCs, to provide important data and a new perspective for the application of berberine in anti-atherosclerosis.

Identification of Hub Genes Associated with Abnormal Endothelial Function in Early Coronary Atherosclerosis

Abnormal coronary endothelial function is an important step in the development of atherosclerosis. Coronary atherosclerosis is one of the main causes of death worldwide. We constructed a co-expression network to identify hub genes associated with abnormal coronary endothelial function in early coronary atherosclerosis. In brief, we used the GSE132651 dataset from the gene expression omnibus database. The top 5000 genes with greatest variances were used for weighted gene co-expression network analysis, and the module most strongly correlated with abnormal coronary endothelial function was chosen as key module. Functional enrichment analysis was performed for genes in the key module, a protein-protein interaction network was constructed to find hub genes, and gene set enrichment analysis (GSEA) was also performed. Genes were classified into 7 modules, with the midnightblue module being the one that was most related to abnormal coronary endothelial function and containing genes enriched in DNA replication, cell cycle, nucleotide excision repair, and Human T-cell leukemia virus 1 infection. We identified nine hub genes (HOXC5, PRND, PADI3, RC3H1, DAPP1, SIT1, DRICH1, GPRIN2, and RHO), which differently expressed in abnormal and normal coronary endothelial function samples. GSEA suggested that samples associated with abnormal coronary endothelial function and highly expressed hub genes were linked with immune, coagulation, hypoxia, and angiogenesis processes. These hub genes, their expression pattern, and pathways may be involved in the development of abnormal coronary endothelial function and promotion of early coronary atherosclerosis.

CXCR4 protects bone marrow-derived endothelial progenitor cells against hypoxia through the PI3K/Akt signaling pathway

The present study aimed to investigate the regulatory mechanism of chemokine (C-X-C motif) receptor 4 (CXCR4) on endothelial progenitor cells (EPCs) through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway under hypoxic conditions. Mononuclear cells were isolated from the bone marrow (BM) of young Sprague-Dawley (SD) rats. Bone marrow-derived endothelial progenitor cells (BM-EPCs) were characterized by using Dil-labeled acetylated low-density lipoprotein (Dil-ac-LDL) and fluorescein isothiocyanate-labeled UEA (FITC-UEA-1). Phenotype identification of BM-EPCs was based on red cytoplasm and green cytomembrane. Flow cytometry was employed to examine the markers CD14, CD34, and KDR. Expression level of the EPC-specific surface marker CD14 was found to be negative, while the expression level of CD34 and KDR was positive. In addition, CXCR4 was stably overexpressed in BM-EPCs after transfection with adenovirus-CXCR4. Cell proliferation, migration and apoptosis abilities were measured through the application of CCK-8, followed by Transwell and flow cytometry assays. The expression level of CXCR4, PI3K and Akt was determined by reverse transcription-quantitative PCR and western blotting assays. Functional experiments demonstrated that hypoxia inhibited BM-EPC proliferation and migration, while accelerating BM-EPC apoptosis. Additionally, CXCR4 was found to promote proliferation and migration, and suppress apoptosis in BM-EPCs with or without hypoxia treatment. Evidence also demonstrated that CXCR4 markedly upregulated the expression levels of PI3K and Akt. Furthermore, PI3K inhibitor (LY294002) and CXCR4 inhibitor (AMD3100) effectively inhibited the proliferation, migration and resistance to apoptosis of CXCR4-mediated BM-EPCs under hypoxic conditions.

Role of Stromal Cell-Derived Factor-1 in Endothelial Progenitor Cell-Mediated Vascular Repair and Regeneration

Endothelial progenitor cells (EPCs) are immature endothelial cells that participate in vascular repair and postnatal neovascularization and provide a novel and promising therapy for the treatment of vascular disease. Studies in different animal models have shown that EPC mobilization through pharmacological agents and autologous EPC transplantation contribute to restoring blood supply and tissue regeneration after ischemic injury. However, these effects of the progenitor cells in clinical studies exhibit mixed results. The therapeutic efficacy of EPCs is closely associated with the number of the progenitor cells recruited into ischemic regions and their functional abilities and survival in injury tissues. In this review, we discussed the regulating role of stromal cell-derived factor-1 (also known CXCL12, SDF-1) in EPC mobilization, recruitment, homing, vascular repair and neovascularization, and analyzed the underlying machemisms of these functions. Application of SDF-1 to improve the regenerative function of EPCs following vascular injury was also discussed. SDF-1 plays a crucial role in mobilizing EPC from bone marrow into peripheral circulation, recruiting the progenitor cells to target tissue and protecting against cell death under pathological conditions; thus improve EPC regenerative capacity. SDF-1 are crucial for regulating EPC regenerative function, and provide a potential target for improve therapeutic efficacy of the progenitor cells in treatment of vascular disease.

Advances of Endothelial Progenitor Cells in the Development of Depression

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

Irisin in atherosclerosis

Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.

Ultrasound and Magnetic Responsive Drug Delivery Systems for Cardiovascular Application

With the increasing insight into molecular mechanisms of cardiovascular disease, a promising solution involves directly delivering genes, cells, and chemicals to the infarcted myocardium or impaired endothelium. However, the limited delivery efficiency after administration fails to reach the therapeutic dose and the adverse off-target effect even causes serious safety concerns. Controlled drug release via external stimuli seems to be a promising method to overcome the drawbacks of conventional drug delivery systems (DDSs). Microbubbles and magnetic nanoparticles responding to ultrasound and magnetic fields respectively have been developed as an important component of novel DDSs. In particular, several attempts have also been made for the design and fabrication of dual-responsive DDS. This review presents the recent advances in the ultrasound and magnetic fields responsive DDSs in cardiovascular application, followed by their current problems and future reformation.

miR-25-5p regulates endothelial progenitor cell differentiation in response to shear stress through targeting ABCA1

The importance of flow shear stress (SS) on the differentiation of endothelial progenitor cells (EPCs) has been demonstrated in various studies. Cholesterol retention and microRNA regulation have been also proposed as relevant factors involved in this process, though evidence regarding their regulatory roles in the differentiation of EPCs is currently lacking. In the present study on high shear stress (HSS)-induced differentiation of EPCs, we investigated the importance of ATP-binding cassette transporter 1 (ABCA1), an important regulator in cholesterol efflux, and miR-25-5p, a potential regulator of endothelial reconstruction. We first revealed an inverse correlation between miR-25-5p and ABCA1 expression levels in EPCs under HSS treatment; their direct interaction was subsequently validated by a dual-luciferase reporter assay. Further studies using flow cytometry and quantitative polymerase chain reaction demonstrated that both miR-25-5p overexpression and ABCA1 inhibition led to elevated levels of specific markers of endothelial cells, with concomitant downregulation of smooth muscle cell markers. Finally, knockdown of ABCA1 in EPCs significantly promoted tube formation, which confirmed our conjecture. Our current results suggest that miR-25-5p might regulate the differentiation of EPCs partially through targeting ABCA1, and such a mechanism might account for HSS-induced differentiation of EPCs.

Stem cell therapies and benefaction of somatic cell nuclear transfer cloning in COVID-19 era

BACKGROUND

The global health emergency of COVID-19 has necessitated the development of multiple therapeutic modalities including vaccinations, antivirals, anti-inflammatory, and cytoimmunotherapies, etc. COVID-19 patients suffer from damage to various organs and vascular structures, so they present multiple health crises. Mesenchymal stem cells (MSCs) are of interest to treat acute respiratory distress syndrome (ARDS) caused by SARS-CoV-2 infection.

MAIN BODY

Stem cell-based therapies have been verified for prospective benefits in copious preclinical and clinical studies. MSCs confer potential benefits to develop various cell types and organoids for studying virus-human interaction, drug testing, regenerative medicine, and immunomodulatory effects in COVID-19 patients. Apart from paving the ways to augment stem cell research and therapies, somatic cell nuclear transfer (SCNT) holds unique ability for a wide range of health applications such as patient-specific or isogenic cells for regenerative medicine and breeding transgenic animals for biomedical applications. Being a potent cell genome-reprogramming tool, the SCNT has increased prominence of recombinant therapeutics and cellular medicine in the current era of COVID-19. As SCNT is used to generate patient-specific stem cells, it avoids dependence on embryos to obtain stem cells.

CONCLUSIONS

The nuclear transfer cloning, being an ideal tool to generate cloned embryos, and the embryonic stem cells will boost drug testing and cellular medicine in COVID-19.

Mobilization of endothelial progenitor cells promotes angiogenesis after full thickness excision by AMD3100 combined with G-CSF in diabetic mice by SDF-1/CXCR4 axis

AIM

The aim of the present study was to investigate the effect of the mobilization of EPCs by AMD3100 combined with G-CSF on wound healing in diabetic mice.

METHODS

The full-thickness excisional wounds model of diabetic mice (db/db) was examined by hematoxylin and eosin staining, immunohistochemical staining, and western blotting to compare the wound healing and neovascularization among the combination, AMD3100 alone, G-CSF alone, and control groups.

RESULTS

The wounds reached the complete closure in the combination, AMD3100 alone, G-CSF alone, and control groups on days 17, 20, 21, 21 after surgery, respectively. In addition, the combination group promoted the inflammatory cell recruitment and glandular formation. On day 10 from injury, the protein expression of CD31 in the combination group was significantly higher compared with the other three groups (p < 0.001). The level of SDF-1 protein remained high in the combined group until on day 10 after surgery (p < 0.001).

CONCLUSION

The mobilization of endogenous EPCs by AMD3100 combine with G-CSF is able to enhance the complete healing of full-thickness wounds and neovascularization in db/db mice may by SDF-1/CXCR4 axis. These findings provided a novel method and indication of duration of mobilization on diabetic wound healing and tissue regeneration.

External Counterpulsation Attenuates Hypertensive Vascular Injury Through Enhancing the Function of Endothelial Progenitor Cells

Background

Vascular injury is a landmark of hypertension and enhanced external counterpulsation (EECP) has been identified as a noninvasive treatment to restore the capacity of endothelial cells. However, the effect of EECP on blood pressure lowering in hypertension and the potential mechanism remain unknown.

Methods

We measured the ambulatory blood pressure (AMBP) and flow-mediated endothelial dilation (FMD) in the essential hypertensive patients who were randomly assigned to the EECP group (n = 20) or control group (n = 20). We also evaluated in vitro function of endothelial progenitor cells (EPCs). Furthermore, multivariate analysis was performed to determine the actual correlation between EPC function and FMD.

Results

Compared with the control, EECP group exhibited decreased systolic [(133.2 ± 4.9) mmHg vs. (139.3 ± 6.4) mmHg, P < 0.05] and diastolic [(83.4 ± 4.5) mmHg vs. (89.5 ± 7.6) mmHg, P < 0.05] blood pressure and increased FMD value [(8.87 ± 2.46%) vs. (7.51 ± 2.32%), P < 0.01]. In addition, the migration [(47.3 ± 6.4)/hpf vs. (33.4 ± 5.1) hpf, P < 0.05] and adhesion [(45.1 ± 5.5)/hpf vs. (28.4 ± 3.9) hpf, P < 0.05] functions of EPCs in the EECP group were improved significantly, whereas no change was observed in the control. Both migration [odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.27–0.64, P < 0.05] and adhesion (OR = 0.44, 95% CI = −0.0034 to 0.0012, P < 0.05) of EPCs correlated with FMD. After multivariate analysis, the migration (β = 3.37, 95% CI = 1.67–5.33, P < 0.05) and adhesion (β = 3.98, 95% CI = 1.12–6.43, P < 0.05) functions still independently correlated to FMD.

Conclusion

The present study demonstrates for the first time that EECP decreases both systolic and diastolic blood pressure and increases FMD value in hypertension. The fall in endogenous EPCs repair capacity might be an important mechanism of hypertensive vascular injury and could be restored by EECP.

Targeting the Endothelium to Achieve Cardioprotection

Despite considerable improvements in the treatment of myocardial infarction, it is still a highly prevalent disease worldwide. Novel therapeutic strategies to limit infarct size are required to protect myocardial function and thus, avoid heart failure progression. Cardioprotection is a research topic with significant achievements in the context of basic science. However, translation of the beneficial effects of protective approaches from bench to bedside has proven difficult. Therefore, there is still an unmet need to study new avenues leading to protecting the myocardium against infarction. In line with this, the endothelium is an essential component of the cardiovascular system with multiple therapeutic targets with cardioprotective potential. Endothelial cells are the most abundant non-myocyte cell type in the heart and are key players in cardiovascular physiology and pathophysiology. These cells can regulate vascular tone, angiogenesis, hemostasis, and inflammation. Accordingly, endothelial dysfunction plays a fundamental role in cardiovascular diseases, which may ultimately lead to myocardial infarction. The endothelium is of paramount importance to protect the myocardium from ischemia/reperfusion injury via conditioning strategies or cardioprotective drugs. This review will provide updated information on the most promising therapeutic agents and protective approaches targeting endothelial cells in the context of myocardial infarction.

Experimental Study on the Effect of Allogeneic Endothelial Progenitor Cells on Wound Healing in Diabetic Mice

Endothelial progenitor cells (EPCs) are involved in the neovascularization in traumatic and ischemic sites, but EPCs are "detained" in bone marrow under diabetic conditions, which results in reduction of the number of EPCs and their biological activity in peripheral blood. Based on our previous study to mobilize autologous bone marrow EPCs by administering AMD3100+G-CSF to realize the optimal effect, our present study is aimed at exploring the effects of transplanting EPCs locally in a wound model of diabetic mice. First, we prepared and identified EPCs, and the biological functions and molecular characteristics were compared between EPCs from DB/+ and DB/DB mice. Then, we performed full-thickness skin resection in DB/DB mice and tested the effect of local transplantation of EPCs on skin wound healing. The wound healing process was recorded using digital photographs. The animals were sacrificed on postoperative days 7, 14, and 17 for histological and molecular analysis. Our results showed that DB/+ EPCs were biologically more active than those of DB/DB EPCs. When compared with the control group, local transplantation of EPCs accelerated wound healing in DB/DB mice by promoting wound granulation tissue formation, angiogenesis, and collagen fiber deposition, but there was no significant difference in wound healing between DB/+ EPCs and DB/DB EPCs transplanted into the wound. Furthermore, local transplantation of EPCs promoted the expression of SDF-1, CXCR4, and VEGF. We speculated that EPC transplantation may promote wound healing through the SDF-1/CXCR4 axis. This point is worth exploring further. Present data are of considerable significance because they raise the possibility of promoting wound healing by isolating autologous EPCs from the patient, which provides a new approach for the clinical treatment of diabetic wounds in the future.

IFN-I Mediates Dysfunction of Endothelial Progenitor Cells in Atherosclerosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease including the cardiovascular system. Atherosclerosis is the most common cardiovascular complication of SLE and a significant risk factor for morbidity and mortality. Vascular damage/protection mechanism in SLE patients is out of balance, caused by the cascade reaction among oxidative stress, proinflammatory cytokines, Neutrophil Extracellular Traps, activation of B cells and autoantibodies and abnormal T cells. As a precursor cell repairing vascular endothelium, endothelial progenitor cells (EPCs) belong to the protective mechanism and show the reduced number and impaired function in SLE. However, the pathological mechanism of EPCs dysfunction in SLE remains ill-defined. This paper reviews the latest SLE epidemiology and pathogenesis, discusses the changes in the number and function of EPCs in SLE, expounds the role of EPCs in SLE atherosclerosis, and provides new guidance and theoretical basis for exploring novel targets for SLE treatment.

Rab27a deletion impairs the therapeutic potential of endothelial progenitor cells for myocardial infarction

Endothelial progenitor cell (EPC) transplantation has shown advantages in the treatment of myocardial infarction (MI) in animal models and clinical trials through mechanisms of direct intercellular contacts, autocrine, and paracrine. However, the effects of EPC transplantation for MI treatment remain controversial and the underlying mechanisms have not been fully elucidated. Here, we explored the role of Rab27a in the therapeutic potential of EPC transplantation in MI. We found that Rab27a knockout impaired the viability, and reduced the proliferation and tube formation function of ECPs. The recovery of cardiac function and improvement of ventricular remodeling from EPCs transplantation were significantly damaged by Rab27a deletion in vivo. Rab27a deletion inhibited the protein expression of phosphoinositide 3-kinase (PI3K) and cyclin D1 and the phosphorylation levels of Akt and FoxO3a. Therefore, Rab27a knockout suppressed the PI3K-Akt-FoxO3a/cyclin D1 signaling pathway. Furthermore, Rab27a ablation dramatically reduced exosome release in EPCs. These results demonstrated that Rab27a plays an essential role in EPC functions. The elucidation of this mechanism provides novel insights into EPC transplantation as a promising treatment for post-MI injuries.

Circulating endothelial progenitor cells during pregnancy in multiple sclerosis

Background

Endothelial progenitor cells (EPCs) have been shown to increase during physiological pregnancy and are believed to play a fundamental role in the process of placentation. Reduced levels of EPCs during pregnancy have been associated with preeclampsia and miscarriage. Women with multiple sclerosis (MS) are not at increased risk of preeclampsia nor of general adverse obstetric outcome, in contrast with some other autoimmune diseases.

Objective

The aim of this study was to evaluate circulating EPCs levels in pregnant patients with MS.

Methods

CD34+ and CD133+ were longitudinally detected by flow cytometry in the maternal plasma of 29 healthy controls and 9 MS patients and in the cord blood of their newborns.

Results

EPCs were affected by pregnancy with the same trend in both groups (CD34+ p = 0.0342; CD133+ p = 0.0347). EPCs during pregnancy were increased in MS (mean ± SD: CD34+ cells 0.038 ± 0.010; CD133+ 0.024 ± 0.009) with respect to healthy controls (mean ± SD: CD34+ cells 0.022 ± 0.006; CD133+ 0.016 ± 0.004), CD34+ p = 0.0004; CD133+ p = 0.0109. EPCs levels of the cord blood of MS patients' newborns mild correlated with maternal EPC levels at delivery (CD34+: spearman’s Rho 0.658, p = 0.054; CD133+: spearman’s Rho 0.758, p = 0.018).

Conclusions

This work identified increased circulating EPC levels during pregnancy, following the same trend both in MS patients and healthy controls. Despite the similar trend, the levels of circulating EPCs were significantly higher in MS patients with respect to the control population. A correlation was also found in MS patients between cord blood EPCs and circulating EPCs at delivery.

Electronic supplementary material

The online version of this article (10.1007/s10072-020-04648-3) contains supplementary material, which is available to authorized users.

Blood pressure control is not enough to normalize endothelial repair by progenitor cells

Patients presenting with classical cardiovascular risk factors within acceptable or average value ranges often develop cardiovascular disease, suggesting that other risk factors need to be considered. Considering that endothelial progenitor cells (EPCs) contribute to endothelial repair, we investigated whether EPCs might be such a factor. We compared the ability of peripheral blood EPCs to attach to extracellular matrix proteins and to grow and function in culture, between controlled hypertensive patients exhibiting a Framingham score (FS) of <10% while showing severe vascular impairment (intima-media thickness/diameter, carotid-femoral pulse wave velocity, brachial artery flow-mediated dilation, carotid and femoral atherosclerotic plaque presence; vulnerable group, N = 30) and those with an FS of ≥10% and scarce vascular changes (protected group, N = 30). When compared with vulnerable patients, protected patients had significantly higher early and late-EPC and early and late-tunneling nanotube (TNT) numbers. Significant negative associations were found between vascular damage severity and early EPC, late-EPC, or late-TNT numbers, whereas EPC or TNT numbers and patient characteristics or cardiovascular risk factors were not associated. Except for protected patients, in all controlled hypertensive patients, early and late-EPC and early and late-TNT counts were significantly lower than those in the normotensive subjects studied (N = 30). We found that the disparity in vascular status between patients presenting with both an FS of ≥10% and scarce vascular changes and those presenting with both an FS of <10% and severe vascular impairment is related to differences in peripheral blood EPC and TNT numbers. These observations support the role of EPCs as contributors to vascular injury repair and suggest that EPC numbers may be a potential cardiovascular risk factor to be included in the FS calculation.NEW & NOTEWORTHY As individuals who present with risk factors within acceptable or average value ranges often develop cardiovascular (CV) disease, it has been suggested that other CV risk factors need to be considered in addition to those that are commonly combined in the Framingham score (FS) to estimate the risk of general CV disease. We investigated whether peripheral endothelial progenitor cells (EPCs) and tunneling nanotubes (TNTs) deserve to be considered. Here we report that EPCs and TNTs are significantly lower in controlled hypertensive patients versus normotensive subjects and that the disparity in vascular status between patients presenting with an FS of ≥10% with scarce vascular changes and those presenting with an FS of <10% with severe vascular impairment is related to differences in EPC and TNT numbers. These data point to EPC and TNT numbers as potential CV risk factors to be included in the FS calculation.

Basic and Therapeutic Aspects of Angiogenesis Updated

All organisms growing beyond the oxygen diffusion limit critically depend on a functional vasculature for survival. Yet blood vessels are far more than passive, uniform conduits for oxygen and nutrient supply. A remarkable organotypic heterogeneity is brought about by tissue-specific differentiated endothelial cells (lining the blood vessels' lumen) and allows blood vessels to deal with organ-specific demands for homeostasis. On the flip side, when blood vessels go awry, they promote life-threatening diseases characterized by endothelial cells inappropriately adopting an angiogenic state (eg, tumor vascularization) or becoming dysfunctional (eg, diabetic microvasculopathies), calling respectively for antiangiogenic therapies and proangiogenic/vascular regenerative strategies. In solid tumors, despite initial enthusiasm, growth factor-based (mostly anti-VEGF [vascular endothelial growth factor]) antiangiogenic therapies do not sufficiently live up to the expectations in terms of efficiency and patient survival, in part, due to intrinsic and acquired therapy resistance. Tumors cunningly deploy alternative growth factors than the ones targeted by the antiangiogenic therapies to reinstigate angiogenesis or revert to other ways of securing blood flow, independently of the targeted growth factors. In trying to alleviate tissue ischemia and to repair dysfunctional or damaged endothelium, local in-tissue administration of (genes encoding) proangiogenic factors or endothelial (stem) cells harnessing regenerative potential have been explored. Notwithstanding evaluation in clinical trials, these approaches are often hampered by dosing issues and limited half-life or local retention of the administered agents. Here, without intending to provide an all-encompassing historical overview, we focus on some recent advances in understanding endothelial cell behavior in health and disease and identify novel molecular players and concepts that could eventually be considered for therapeutic targeting.

MicroRNA and ROS Crosstalk in Cardiac and Pulmonary Diseases

Reactive oxygen species (ROS) affect many cellular functions and the proper redox balance between ROS and antioxidants contributes substantially to the physiological welfare of the cell. During pathological conditions, an altered redox equilibrium leads to increased production of ROS that in turn may cause oxidative damage. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level contributing to all major cellular processes, including oxidative stress and cell death. Several miRNAs are expressed in response to ROS to mediate oxidative stress. Conversely, oxidative stress may lead to the upregulation of miRNAs that control mechanisms to buffer the damage induced by ROS. This review focuses on the complex crosstalk between miRNAs and ROS in diseases of the cardiac (i.e., cardiac hypertrophy, heart failure, myocardial infarction, ischemia/reperfusion injury, diabetic cardiomyopathy) and pulmonary (i.e., idiopathic pulmonary fibrosis, acute lung injury/acute respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, lung cancer) compartments. Of note, miR-34a, miR-144, miR-421, miR-129, miR-181c, miR-16, miR-31, miR-155, miR-21, and miR-1/206 were found to play a role during oxidative stress in both heart and lung pathologies. This review comprehensively summarizes current knowledge in the field.

Adjunctive Cilostazol to Dual Antiplatelet Therapy to Enhance Mobilization of Endothelial Progenitor Cell in Patients with Acute Myocardial Infarction: A Randomized, Placebo-Controlled EPISODE Trial

Background: Endothelial progenitor cells (EPCs) have the potential to protect against atherothrombotic event occurrences. There are no data to evaluate the impact of cilostazol on EPC levels in high-risk patients. Methods: We conducted a randomized, double-blind, placebo-controlled trial to assess the effect of adjunctive cilostazol on EPC mobilization and platelet reactivity in patients with acute myocardial infarction (AMI). Before discharge, patients undergoing percutaneous coronary intervention (PCI) were randomly assigned to receive cilostazol SR capsule (200-mg) a day (n = 30) or placebo (n = 30) on top of dual antiplatelet therapy (DAPT) with clopidogrel and aspirin. Before randomization (baseline) and at 30-day follow-up, circulating EPC levels were analyzed using flow cytometry and hemostatic measurements were evaluated by VerifyNow and thromboelastography assays. The primary endpoint was the relative change in EPC levels between baseline and 30-day. Results: At baseline, there were similar levels of EPC counts between treatments, whereas patients with cilostazol showed higher levels of EPC counts compared with placebo after 30 days. Cilostazol versus placebo treatment displayed significantly higher changes in EPC levels between baseline and follow-up (ΔCD133⁺/KDR⁺: difference 216%, 95% confidence interval (CI) 44~388%, p = 0.015; ΔCD34⁺/KDR⁺: difference 183%, 95% CI 25~342%, p = 0.024). At 30-day follow-up, platelet reactivity was lower in the cilostazol group compared with the placebo group (130 ± 45 versus 169 ± 62 P2Y12 Reaction Unit, p = 0.009). However, there were no significant correlations between the changes of EPC levels and platelet reactivity. Conclusion: Adjunctive cilostazol on top of clopidogrel and aspirin versus DAPT alone is associated with increased EPC mobilization and decreased platelet reactivity in AMI patients, suggesting its pleiotropic effects against atherothrombotic events (NCT04407312).

N-acetylcysteine differentially regulates the populations of bone marrow and circulating endothelial progenitor cells in mice with limb ischemia

Endothelial progenitor cells (EPCs) are important to tissue repair and regeneration especially after ischemic injury, and very heterogeneous in phenotypes and biological features. Reactive oxygen species are involved in regulating EPC number and function. N-acetylcysteine (NAC) inhibits ischemia-induced reactive oxygen species formation and promotes ischemic limb recovery. This study was to evaluate the effect of NAC on EPC subpopulations in bone marrow (BM) and blood in mice with limb ischemia. Limb ischemia was induced by femoral artery ligation in male C57BL/6 mice with or without NAC treatment. EPC subpopulations, intracellular reactive oxygen species production, cell proliferation and apoptosis in BM and blood cells were analyzed at baseline, day 3 (acute ischemia) and 21 (chronic) after ligation. c-Kit+/CD31+, Sca-1+/Flk-1+, CD34+/CD133+, and CD34+/Flk-1+ were used to define EPC subpopulations. Limb blood flow, function, muscle structure, and capillary density were evaluated with laser Doppler perfusion imaging, treadmill test, and immunohistochemistry, respectively, at day 3, 7, 14 and 21 post ischemia. Reactive oxygen species production in circulating and BM mononuclear cells and EPCs populations were significantly increased in BM and blood in mice with acute and chronic ischemia. NAC treatment effectively blocked ischemia-induced reactive oxygen species production in circulating and BM mononuclear cells, and selectively increased EPC population in circulation, not BM, with preserved proliferation in mice with chronic ischemia, and enhanced limb blood flow and function recovery, while preventing acute ischemia-induced increase in BM and circulating EPCs. These data demonstrated that NAC selectively enhanced circulating EPC population in mice with chronic limb ischemia.