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

Circulating Endothelial Progenitor Cells and Metabolic Factors in Childhood Cancer Survivors

BACKGROUND

Circulating endothelial progenitor cells (cEPCs) are known to have an active role in maintaining healthy vessel anatomy and function. The purpose of the present study was to quantify cEPCs in childhood cancer survivors after treatment completion and evaluate possible associations of their levels with metabolic disorders.

METHODS

Circulating EPCs isolated from peripheral blood samples from 383 children and adolescent cancer survivors diagnosed with acute lymphoblastic leukemia (ALL), lymphomas, or solid tumors (ST) were quantified 1, 3, and more than 3 years after treatment completion using flow cytometry. Their levels were compared to 200 healthy controls, and multivariate logistic regression analysis was applied to seek correlations with metabolic disorders, including hypertension, obesity, hyperglycemia, and dyslipidemia.

RESULTS

The levels of CD34+/CD133+/VEGFR+ and CD34+/VEGFR+ cEPCs were significantly higher in children treated for solid tumors and lymphomas compared to the ALL group. Compared to controls, both cEPCs populations were found to be increased in patients treated for ST (CD34+/CD133+/VEGFR+, p = 0.0049; CD34+/VEGFR+, p = 0.0001). Declining trends of CD34+/VEGFR+ and CD34+/CD133+/VEGFR+ levels were observed in patients treated for solid tumors and lymphomas during the first 3 years after treatment, while an increasing trend was observed in ALL patients (p = 0.01). Three years after treatment completion, all groups had cEPC levels comparable to the control group. By multivariate regression analysis, no significant differences were observed in children with metabolic disorders, including hypertension, obesity, hyperglycemia, and dyslipidemia.

CONCLUSION

Significant differences in cEPC levels were observed in childhood cancer survivors during the first year after treatment completion, which were comparable to healthy controls after 3 years post-treatment.

Progenitor cells and circulating endothelial cells are associated with disease activity and damage in systemic lupus erythematosus patients

BackgroundDespite advancements in treatment, patients with Systemic Lupus Erythematosus (SLE) frequently experience disease flares, which contribute to organ damage and increase the risk of premature death. Assessing disease activity is essential for optimizing treatment and preventing further organ damage. This study aimed to investigate the relationship between levels of progenitor and circulating endothelial cells and SLE disease activity, as well as accumulated organ damage.MethodsWe conducted a case-control study measuring levels of CD34+CD45low/- progenitor cells, CD34+CD45low/-CD133+ progenitor cells, Endothelial Progenitor Cells (EPC), and Circulating Endothelial Cells (CEC) in peripheral blood using flow cytometry.ResultsThe study included 32 SLE patients and 28 matched controls. SLE patients exhibited significantly lower levels of CD34+CD45low/- progenitor cells (p = .001), CD34+CD45low/-CD133+ progenitor cells (p = .016), EPC (p = .018), and CEC (p < .001) compared to controls. Additionally, the cell subpopulations correlated with SLE activity biomarkers, with CD34+CD45low/- progenitor cells showing a moderate negative correlation with C3 and C4 levels. Notably, patients with an SDI score ≥1 had significantly higher levels of CD34+CD45low/- progenitor cells, CD34+CD45low/- CD133+ progenitor cells, EPC, and CEC compared to those without organ damage (p = .0073, p = .018, p = .018, and p = .020, respectively).ConclusionOur findings reveal that CD34+CD45low/- progenitor cells, CD34+CD45low/-CD133+ progenitor cells, EPC, and CEC are significantly reduced in SLE patients and are associated with disease activity and organ damage. These results suggest that CD34+CD45low/- progenitor cells, in particular, could serve as potential biomarkers for monitoring disease activity and organ damage in SLE patients. Prospective studies are warranted to confirm these findings.

Decreased Endothelial Progenitor Cells Are Associated with Severe Coronary Artery Disease: Insights from a Clinical Study

Endothelial progenitor cells (EPCs) play a crucial role in vascular repair, and their depletion has been involved in coronary artery disease (CAD) severity. This study examines the relationship between circulating EPC levels and CAD complexity, as quantified by the Syntax Score I. A total of 85 patients undergoing coronary angiography were enrolled, with EPCs quantified using flow cytometry. EPC proportion showed a significant inverse relationship with CAD severity, measured by Syntax Score I. Additionally, we investigated EPC levels in patients presenting with acute coronary syndrome (ACS) and found that EPC depletion was more pronounced in this group compared to non-ACS patients (median EPC count: 0.35 vs. 0.61, p = 0.027). These findings suggest that lower EPC levels are indicative of more severe CAD and ACS, reinforcing their potential as biomarkers for cardiovascular risk stratification, monitoring disease advancement, and identifying patients at risk of adverse events.

Endothelial Homeostasis Under the Influence of Alcohol-Relevance to Atherosclerotic Cardiovascular Disease

Alcohol, in the form of ethyl alcohol or ethanol, is a widely consumed substance with significant implications for human health. Research studies indicate multifaceted effects of alcohol on the cardiovascular system with both protective and harmful effects on atherosclerotic cardiovascular disease (ASCVD), depending on the amount involved and the pattern of consumption. Among the critical components of the cardiovascular system are endothelial cells which line blood vessels. These cells are pivotal in maintaining vessel homeostasis, regulating blood flow, and preventing thrombosis. Their compromised function correlates with arterial disease progression and is predictive of cardiovascular events. Here we review research investigating how alcohol exposure affects the endothelium to gain insight into potential mechanisms mediating alcohol's influence on ASCVD underlying heart attacks and strokes. Studies highlight opposite effects of low versus high levels of alcohol on many endothelial functions. In general, low-to-moderate levels of alcohol (~5-25 mM) maintain the endothelium in a non-activated state supporting vascular homeostasis, while higher alcohol levels (≥50 mM) lead to endothelial dysfunction and promotes atherosclerosis. These biphasic endothelial effects of alcohol might underlie the varying impacts of different alcohol consumption patterns on ASCVD.

Endothelialization of coronary stents after intra-luminal adenoviral VEGF-A gene transfer in a preclinical porcine restenosis model - Studies with optical coherence tomography, angioscopy, multiphoton and scanning electron microscopy

BACKGROUND

Coronary stenting operations have become the main option for the treatment of coronary heart disease. Vessel recovery after stenting has emerged as a critical factor in reducing possible complications. In this study, we evaluated the feasibility, safety and efficacy of locally administered intraluminal gene therapy delivered using a specialized infusion balloon catheter.

METHODS

Sixteen pigs received bare metal stents (BMS) in the left circumflex coronary artery and drug-eluting stents (DES) in the right coronary artery. Adenoviral (Ad) gene transfers (dose 1,5e10 pfu) of VEGF-A and LacZ were performed with a ClearWay™ RX infusion balloon catheter on both stents. In vivo imaging included angiography, OCT and angioscopy. Tissue samples were collected for analyses at day 14 and studied using scanning electron microscopy and multiphoton microscopy.

RESULTS

AdVEGF-A accelerated re-endothelialization in the BMS compared to the other groups. The highest restenosis was in the BMS AdLacZ group. DES groups had statistically significant reduced maximum stenosis compared to BMS AdLacZ. No major in-stent thrombosis events were detected. Ex vivo imaging showed that intraarterial imaging is not very accurate in the detection of endothelial layer. Biodistribution of the Ad vector and measured safety parameters (off-target tissues and blood tests) did not show any major safety concerns.

CONCLUSION

Adenoviral gene transfer using the ClearWay™ RX catheter was feasible and safe. AdVEGF-A accelerated re-endothelization in BMS. However, DES showed better outcomes in the short-term regarding restenosis and do not benefit from intraluminal AdVEGF-A gene transfer.

Stent strategies: Endothelial progenitor cell coated stents vs sirolimus eluting stents in a pairwise meta-analysis

BACKGROUND

Endothelial progenitor cells (EPCs) capturing stents were developed to enhance endothelial repair and reduce the risk of stent thrombosis, addressing limitations of Sirolimus-Eluting Stents (SES). This study aims to compare the safety and efficacy of EPC stents versus SES in patients undergoing percutaneous coronary intervention (PCI).

METHODS

We performed a meta-analysis following PRISMA guidelines in patients undergoing PCI treated with Sirolimus eluting stent (SES) vs the use of EPC stents and recognized 8 clinical trials with patients undergoing PCI and reporting outcomes such as Target Lesion Failure (TLF), stent thrombosis, and revascularisation. Relative risks were calculated using a random effects model and heterogeneity was assessed with I^2 statistics.

RESULTS

The EPC group showed higher incidence of TLF (RR ​= ​1.28), MI(RR ​= ​1.10), and cardiac death (RR ​= ​1.19) compared to SES, though these differences were not statistically significant. Revascularisation rates were significantly higher in EPC group with TVR (RR ​= ​1.60) and TLR(RR ​= ​2.20) while stent thrombosis was lower (RR ​= ​0.93).

CONCLUSION

The results of this EPC study reveals that while EPC stents show promise in revascularisation and lowering stent thrombosis, they are also associated with higher incidence of adverse events. The utility of EPC, especially vast reendothelialization, may have niche applications but their full potential can be realized with more rigorous trials as a clear advantage over SES remains lacking.

ANRIL's Epigenetic Regulation and Its Implications for Cardiovascular Disorders

Cardiovascular disorders (CVDs) are a major global health concern, but their underlying molecular mechanisms are not fully understood. Recent research highlights the role of long noncoding RNAs (lncRNAs), particularly ANRIL, in cardiovascular development and disease. ANRIL, located in the human genome's 9p21 region, significantly regulates cardiovascular pathogenesis. It controls nearby tumor suppressor genes CDKN2A/B through epigenetic pathways, influencing cell growth and senescence. ANRIL interacts with epigenetic modifiers, leading to altered histone modifications and gene expression changes. It also acts as a transcriptional regulator, impacting key genes in CVD development. ANRIL's involvement in cardiovascular epigenetic regulation suggests potential therapeutic strategies. Manipulating ANRIL and its associated epigenetic modifiers could offer new approaches to managing CVDs and preventing their progression. Dysregulation of ANRIL has been linked to various cardiovascular conditions, including coronary artery disease, atherosclerosis, ischemic stroke, and myocardial infarction. This abstract provides insights from recent research, emphasizing ANRIL's significance in the epigenetic landscape of cardiovascular disorders. By shedding light on ANRIL's role in cellular processes and disease development, the abstract highlights its potential as a therapeutic target for addressing CVDs.

Recent Insights into Endogenous Mammalian Cardiac Regeneration Post-Myocardial Infarction

Myocardial infarction (MI) is a critical global health issue and a leading cause of heart failure. Indeed, while neonatal mammals can regenerate cardiac tissue mainly through cardiomyocyte proliferation, this ability is lost shortly after birth, resulting in the adult heart's inability to regenerate after injury effectively. In adult mammals, the adverse cardiac remodelling, which compensates for the loss of cardiac cells, impairs cardiac function due to the non-contractile nature of fibrotic tissue. Moreover, the neovascularisation after MI is inadequate to restore blood flow to the infarcted myocardium. This review aims to synthesise the most recent insights into the molecular and cellular players involved in endogenous myocardial and vascular regeneration, facilitating the identification of mechanisms that could be targeted to trigger cardiac regeneration, reduce fibrosis, and improve functional recovery post-MI. Reprogramming adult cardiomyocytes to regain their proliferative potential, along with the modulation of target cells responsible for neovascularisation, represents promising therapeutic strategies. An updated overview of endogenous mechanisms that regulate both myocardial and coronary vasculature regeneration-including stem and progenitor cells, growth factors, cell cycle regulators, and key signalling pathways-could help identify new critical intervention points for therapeutic applications.

Biomechanical factors and atherosclerosis localization: insights and clinical applications

Although the entire vascular bed is constantly exposed to the same risk factors, atherosclerosis manifests a distinct intra-individual pattern in localization and progression within the arterial vascular bed. Despite shared risk factors, the development of atherosclerotic plaques is influenced by physical principles, anatomic variations, metabolic functions, and genetic pathways. Biomechanical factors, particularly wall shear stress (WSS), play a crucial role in atherosclerosis and both low and high WSS are associated with plaque progression and heightened vulnerability. Low and oscillatory WSS contribute to plaque growth and arterial remodeling, while high WSS promotes vulnerable changes in obstructive coronary plaques. Axial plaque stress and plaque structural stress are proposed as biomechanical indicators of plaque vulnerability, representing hemodynamic stress on stenotic lesions and localized stress within growing plaques, respectively. Advancements in imaging and computational fluid dynamics techniques enable a comprehensive analysis of morphological and hemodynamic properties of atherosclerotic lesions and their role in plaque localization, evolution, and vulnerability. Understanding the impact of mechanical forces on blood vessels holds the potential for developing shear-regulated drugs, improving diagnostics, and informing clinical decision-making in coronary atherosclerosis management. Additionally, Computation Fluid Dynamic (CFD) finds clinical applications in comprehending stent-vessel dynamics, complexities of coronary bifurcations, and guiding assessments of coronary lesion severity. This review underscores the clinical significance of an integrated approach, concentrating on systemic, hemodynamic, and biomechanical factors in atherosclerosis and plaque vulnerability among patients with coronary artery disease.

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

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

Isolation of circulating endothelial cells provides tool to determine endothelial cell senescence in blood samples

Circulating endothelial cells (CEC) are arising as biomarkers for vascular diseases. However, whether they can be utilized as markers of endothelial cell (EC) senescence in vivo remains unknown. Here, we present a protocol to isolate circulating endothelial cells for a characterization of their senescent signature. Further, we characterize different models of EC senescence induction in vitro and show similar patterns of senescence being upregulated in CECs of aged patients as compared to young volunteers. Replication-(ageing), etoposide-(DNA damage) and angiotensin II-(ROS) induced senescence models showed the expected cell morphology and proliferation-reduction effects. Expression of senescence-associated secretory phenotype markers was specifically upregulated in replication-induced EC senescence. All models showed reduced telomere lengths and induction of the INK4a/ARF locus. Additional p14ARF-p21 pathway activation was observed in replication- and etoposide-induced EC senescence. Next, we established a combined magnetic activated- and fluorescence activated cell sorting (MACS-FACS) based protocol for CEC isolation. Interestingly, CECs isolated from aged volunteers showed similar senescence marker patterns as replication- and etoposide-induced senescence models. Here, we provide first proof of senescence in human blood derived circulating endothelial cells. These results hint towards an exciting future of using CECs as mirror cells for in vivo endothelial cell senescence, of particular interest in the context of endothelial dysfunction and cardiovascular diseases.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

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

Intermediate Monocytes and Circulating Endothelial Cells: Interplay with Severity of Atherosclerosis in Patients with Coronary Artery Disease and Type 2 Diabetes Mellitus

The aim was to investigate the association of monocyte heterogeneity and presence of circulating endothelial cells with the severity of coronary atherosclerosis in patients with coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). We recruited 62 patients with CAD, including 22 patients with DM2. The severity of atherosclerosis was evaluated using Gensini Score. Numbers of classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14+CD16++) monocyte subsets; circulating endothelial progenitor cells; and the presence of circulating endothelial cells were evaluated. Counts and frequencies of intermediate monocytes, but not glycaemia parameters, were associated with the severity of atherosclerosis in diabetic CAD patients (rs = 0.689; p = 0.001 and rs = 0.632; p = 0.002, respectively). Frequency of Tie2+ cells was lower in classical than in non-classical monocytes in CAD patients (p = 0.007), while in patients with association of CAD and T2DM, differences between Tie2+ monocytes subsets disappeared (p = 0.080). Circulating endothelial cells were determined in 100% of CAD+T2DM patients, and counts of CD14++CD16+ monocytes and concentration of TGF-β predicted the presence of circulating endothelial cells (sensitivity 92.3%; specificity 90.9%; AUC = 0.930). Thus, intermediate monocytes represent one of the key determinants of the appearance of circulating endothelial cells in all the patients with CAD, but are associated with the severity of atherosclerosis only in patients with association of CAD and T2DM.

In-stent restenosis after percutaneous coronary intervention: emerging knowledge on biological pathways

Percutaneous coronary intervention (PCI) has evolved significantly over the past four decades. Since its inception, in-stent restenosis (ISR)-the progressive reduction in vessel lumen diameter after PCI-has emerged as the main complication of the procedure. Although the incidence of ISR has reduced from 30% at 6 months with bare-metal stents to 7% at 4 years with drug-eluting stents (DESs), its occurrence is relevant in absolute terms because of the dimensions of the population treated with PCI. The aim of this review is to summarize the emerging understanding of the biological pathways that underlie ISR. In-stent restenosis is associated with several factors, including patient-related, genetic, anatomic, stent, lesion, and procedural characteristics. Regardless of associated factors, there are common pathophysiological pathways involving molecular phenomena triggered by the mechanical trauma caused by PCI. Such biological pathways are responses to the denudation of the intima during balloon angioplasty and involve inflammation, hypersensitivity reactions, and stem cell mobilization particularly of endothelial progenitor cells (EPCs). The results of these processes are either vessel wall healing or neointimal hyperplasia and/or neo-atherosclerosis. Unravelling the key molecular and signal pathways involved in ISR is crucial to identify appropriate therapeutic strategies aimed at abolishing the 'Achille's heel' of PCI. In this regard, we discuss novel approaches to prevent DES restenosis. Indeed, available evidence suggests that EPC-capturing stents promote rapid stent re-endothelization, which, in turn, has the potential to decrease the risk of stent thrombosis and allow the use of a shorter-duration dual antiplatelet therapy.

Targeting Rho kinase to restore endothelial barrier function following vascular scaffold implantation

Vascular scaffold implantation induces injury to the intimal layer and causes discontinuity of the regenerated endothelial monolayer, compromising barrier integrity, increasing permeability, and allowing the transmigration of leukocytes and lipoproteins into the subendothelial space. Mechanical vascular wall stretching triggers Ras homolog family member A (RhoA)/Rho kinase-mediated actomyosin contractility and destabilization of adherens junctions, leading to endothelial barrier dysfunction. Assembly of intercellular adhesion and actin cytoskeletal organization of interendothelial junctions are controlled by downregulation of RhoA guanosine triphosphatase (GTPase)-mediated barrier-disruptive activity and upregulation of repressor-activator protein 1 (Rap1) and Ras-related C3 botulinum toxin substrate 1 (Rac1) GTPase-mediated cytoskeletal reorganization, leading to endothelial barrier stabilization. This review highlights the involvement of Rho GTPases in the disruption of endothelial barrier integrity following vascular scaffold implantation and the targeting of downstream Rho-associated protein kinases, which signal the network to restore endothelial barrier integrity and stability.

In Search of the Holy Grail: Stem Cell Therapy as a Novel Treatment of Heart Failure with Preserved Ejection Fraction

Heart failure, a leading cause of hospitalizations and deaths, is a major clinical problem. In recent years, the increasing incidence of heart failure with preserved ejection fraction (HFpEF) has been observed. Despite extensive research, there is no efficient treatment for HFpEF available. However, a growing body of evidence suggests stem cell transplantation, due to its immunomodulatory effect, may decrease fibrosis and improve microcirculation and therefore, could be the first etiology-based therapy of the disease. In this review, we explain the complex pathogenesis of HFpEF, delineate the beneficial effects of stem cells in cardiovascular therapy, and summarize the current knowledge concerning cell therapy in diastolic dysfunction. Furthermore, we identify outstanding knowledge gaps that may indicate directions for future clinical studies.

Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes

Stent thrombosis remains one of the main causes that lead to vascular stent failure in patients undergoing percutaneous coronary intervention (PCI). Type 2 diabetes mellitus is accompanied by endothelial dysfunction and platelet hyperactivity and is associated with suboptimal outcomes following PCI, and an increase in the incidence of late stent thrombosis. Evidence suggests that late stent thrombosis is caused by the delayed and impaired endothelialization of the lumen of the stent. The endothelium has a key role in modulating inflammation and thrombosis and maintaining homeostasis, thus restoring a functional endothelial cell layer is an important target for the prevention of stent thrombosis. Modifications using specific molecules to induce endothelial cell adhesion, proliferation and function can improve stents endothelialization and prevent thrombosis. Blood endothelial progenitor cells (EPCs) represent a potential cell source for the in situ-endothelialization of vascular conduits and stents. We aim in this review to summarize the main biofunctionalization strategies to induce the in-situ endothelialization of coronary artery stents using circulating endothelial stem cells.