Effect of High-Dose Atorvastatin Reload on the Release of Endothelial Progenitor Cells in Patients on Long-Term Statin Treatment Who Underwent Percutaneous Coronary Intervention (from the ARMYDA-EPC Study)

Role of oxidative stress and inflammation-related signaling pathways in doxorubicin-induced cardiomyopathy

Doxorubicin (DOX) is a powerful and commonly used chemotherapeutic drug, used alone or in combination in a variety of cancers, while it has been found to cause serious cardiac side effects in clinical application. More and more researchers are trying to explore the molecular mechanisms of DOX-induced cardiomyopathy (DIC), in which oxidative stress and inflammation are considered to play a significant role. This review summarizes signaling pathways related to oxidative stress and inflammation in DIC and compounds that exert cardioprotective effects by acting on relevant signaling pathways, including the role of Nrf2/Keap1/ARE, Sirt1/p66Shc, Sirt1/PPAR/PGC-1α signaling pathways and NOS, NOX, Fe²⁺ signaling in oxidative stress, as well as the role of NLRP3/caspase-1/GSDMD, HMGB1/TLR4/MAPKs/NF-κB, mTOR/TFEB/NF-κB pathways in DOX-induced inflammation. Hence, we attempt to explain the mechanisms of DIC in terms of oxidative stress and inflammation, and to provide a theoretical basis or new idea for further drug research on reducing DIC. Video Abstract.

The Role of Endothelial Progenitor Cells in Atherosclerosis and Impact of Anti-Lipemic Treatments on Endothelial Repair

Cardiovascular complications are associated with advanced atherosclerosis. Although atherosclerosis is still regarded as an incurable disease, at least in its more advanced stages, the discovery of endothelial progenitor cells (EPCs), with their ability to replace old and injured cells and differentiate into healthy and functional mature endothelial cells, has shifted our view of atherosclerosis as an incurable disease, and merged traditional theories of atherosclerosis pathogenesis with evolving concepts of vascular biology. EPC alterations are involved in the pathogenesis of vascular abnormalities in atherosclerosis, but many questions remain unanswered. Many currently available drugs that impact cardiovascular morbidity and mortality have shown a positive effect on EPC biology. This review examines the role of endothelial progenitor cells in atherosclerosis development, and the impact standard antilipemic drugs, including statins, fibrates, and ezetimibe, as well as more novel treatments such as proprotein convertase subtilisin/kexin type 9 (PCSK9) modulating agents and angiopoietin-like proteins (Angtpl3) inhibitors have on EPC biology.

Effects of Shen-Yuan-Dan on Periprocedural Myocardial Injury and the Number of Peripheral Blood Endothelial Progenitor Cells in Patients with Unstable Angina Pectoris Undergoing Elective Percutaneous Coronary Intervention

OBJECTIVES

We aimed to investigate the effects of Shen-Yuan-Dan (SYD), a Chinese medicine preparation, on periprocedural myocardial injury (PMI) and the number of peripheral blood endothelial progenitor cells (EPCs) in patients with unstable angina pectoris (UA) who underwent elective percutaneous coronary intervention (PCI).

METHODS

Patients were randomly divided into the experimental (group A) and control (group B) groups through the random number table method. In group A, patients concurrently received the conventional western treatment and SYD orally (4 capsules/time, 3 times/d, from 3 d before surgery to 7 d after surgery). In group B, patients received conventional Western medicine treatment. Both groups underwent coronary angiography, and patients undergoing PCI were eventually included in the study. The following patient data were collected: incidence of PMI, serum CK-MB content before PCI, 4 h, 24 h, and 7 d after PCI, number of CD45dim/-CD34+CD309+ peripheral venous EPCs, and number of CD184 coexpressed EPCs. The incidence of adverse reactions and 30-day major adverse cardiovascular events (MACEs) were also recorded.

RESULTS

Sixty-two patients were finally included in this study, with 32 and 30 in groups A and B, respectively. In group A, the number of peripheral blood EPCs and the number of CD184 coexpressed EPCs at 1 h before surgery were higher than those at 3 d before surgery (37.24 ± 25.20 vs. 22.78 ± 9.60/ml; P < 0.001 and 23.38 ± 15.30 vs. 13.54 ± 8.08/ml; P < 0.001, resp.). The number of peripheral blood EPCs and number of CD184 coexpressed EPCs at 4 h after surgery were lower than those at 1 h before surgery (25.30 ± 11.90 vs. 37.24 ± 25.20/ml; P=0.019 and 15.38 ± 8.78 vs. 23.38 ± 15.30/ml; P=0.013, resp.), but there was no difference at 24 h and at 7 d after surgery in comparison with that at 1 h before surgery (P > 0.05). In group B, compared with that at 1 h before surgery, there existed a decline in the number of EPCs in peripheral blood and the number of CD184 coexpressed EPCs at 4 h after surgery, but without a statistical difference (P > 0.05). Comparing both groups, it was found that the incidence of PMI in group A was lower (6.25% vs. 26.67%; P=0.04), and the serum CK-MB content at 4 and 24 h after surgery was also lower than that in group B (17.33 ± 5.83 vs. 20.38 ± 4.32 U/l; P=0.048 and 15.79 ± 5.32 vs. 19.10 ± 4.93 U/l; P=0.030, resp.). The number of EPCs in peripheral blood and the number of CD184 coexpressed EPCs in group A were higher than those in group B at 1 h before surgery (37.24 ± 25.20 vs. 22.36 ± 12.26/ml; P=0.034 and 23.38 ± 15.30 vs. 13.12 ± 14.62/ml; P=0.013, resp.). In addition, there were no obvious adverse reactions and no 30-day MACEs in both groups during the trial.

CONCLUSION

SYD can reduce PMI and promote the mobilization of EPCs in the perioperative period of elective PCI in patients with UA.

Impact of the Polymorphism rs5751876 of the Purinergic Receptor ADORA2A on Periprocedural Myocardial Infarction in Patients Undergoing Percutaneous Coronary Intervention

Aim: Periprocedural myocardial infarction (PMI), a severe complication of Percutaneous Coronary Intervention (PCI) procedures, has a negative prognostic effect, both at short and long-term follow-up. So far, adenosine's role in preventing PMI has shown contrasting results. A genetic variant of ADORA2A receptor, 1976 C > T, has been suggested as a potential determinant of the interindividual response to adenosine, thus conditioning its potential benefits on PMI. In our study, we investigated whether the ADORA2A 1976 C > T polymorphism is associated with PMI occurrence in patients undergoing coronary stenting.

Methods: The study included consecutive patients undergoing PCI at the Azienda Ospedaliera-Universitaria “Maggiore della Carità,” Novara, Italy, between January 2010 and January 2016. Their genetic status was assessed using polymerase chain reaction (PCR) and restriction-fragment-length-polymorphism technique. Myonecrosis biomarkers were measured at intervals from 6 to 48 hours. PMI was defined as CKMB increased 3 times over the Upper Limit of Normal (ULN), or 50% of pre-PCI value; periprocedural myonecrosis was defined as troponin I increased 3 times over the ULN or by 50% of the baseline value.

Results: We included 1,104 patients undergoing PCI, 863 (78.2%) of whom carried the ADORA2A T-allele. No difference was found for the main demographic, clinical features, or biochemistry parameters. However, C-carriers had lower statin therapy use (p = 0.008) and lower HDL-cholesterol levels (p = 0.01). Homozygous C/C patients had more frequent multivessel disease (p = 0.03), longer lesions (p = 0.01) and Type C lesions (p = 0.01), thus requiring more complex procedures. After correction for baseline confounding factors at multivariate analysis, there was no difference in myocardial necrosis according to the ADORA2A genotype (p = 0.40). In contrast, PMI tended to increase in the homozygous C/C population (p = 0.06), but this trend was attenuated at multivariate analysis after correction for baseline confounding factors (C/C: OR[95%CI]= 1.52 [0.88–2.6], p = 0.14).

Conclusions: Our study showed that the polymorphism rs5751876 of the ADORA2A receptor is associated with a higher prevalence of complex coronary lesions and multivessel disease. However, it does not significantly influence the occurrence of periprocedural MI or myonecrosis.

A new method of culturing rat bone marrow endothelial progenitor cells in vitro

Background

Endothelial progenitor cells (EPCs) play an important role in the re-endothelialization of ischemic cerebrovascular disease. However, the current acquisition method has some deficiencies. This study aimed to design a new and practical method for obtaining EPCs.

Methods

Bone marrow was obtained autologously from the right tibia of living rats. Briefly, the right tibia bone was carefully exposed and two holes (1 mm in diameter) were made in the tuberosity and lower one-third of the tibia, respectively. A PE-50 catheter and syringe (5 mL) were inserted through the holes to aspirate the bone marrow. Bone marrow mononuclear cells (BMMCs) were isolated by density-gradient centrifugation with Ficoll and counted. Adherent cell culture continued for 2 weeks, and the medium was replaced every 3 days.

Results

During the first days of culture, adherent cells formed a monolayer, consisting predominantly of small-sized cells. Single large cells with endothelial morphology were observed. On day 4, the nonadherent cells were removed, and the adherent cells were left for further culture. On day 6-7, a proliferating population of round cells formed clusters in the culture chamber, and morphological analysis revealed a homogeneous population of colony-forming units (CFUs). Large, flat cells with endothelial morphology sprouted from the CFUs, which had nearly disappeared by day 14 of culture. The adherent cells were positive for CD133 and vascular endothelial growth factor receptor 2 (VEGFR2), internalized acetylated low-density lipoprotein, and bound ulex europaeus-agglutinin-I, but were negative for CD45, which correlated with the endothelial morphology and ability to form capillaries of EPCs.

Conclusions

Our results are direct evidence that mononuclear cells (MCS) from living rat bone marrow can be used to culture EPCs in vitro under certain culture conditions, providing a new method for the further study of autologous EPC transplantation.

[6]-Gingerol Ameliorates ISO-Induced Myocardial Fibrosis by Reducing Oxidative Stress, Inflammation, and Apoptosis through Inhibition of TLR4/MAPKs/NF-κB Pathway

SCOPE

[6]-Gingerol is one of the primary pungent constituents of ginger. While [6]-gingerol has many pharmacological effects, its benefits for myocardial fibrosis, including its exact role and underlying mechanisms, remain largely unexplored. The present study is designed to characterize the cardio-protective effects of [6]-gingerol in myocardial fibrosis mice and possible underlying mechanisms.

METHODS AND RESULTS

Mice are subcutaneously injected with isoproterenol (ISO, 10 mg kg^-1 ) and gavaged with [6]-gingerol (10, 20 mg kg^-1 day^-1 ) for 14 days. Pathological alterations, fibrosis, oxidative stress, inflammation response, and apoptosis are examined. In ISO-induced myocardial fibrosis, [6]-gingerol treatment decreases the J-point, heart rate, cardiac weight index, left ventricle weight index, creatine kinase (CK), and lactate dehydrogenase serum levels, calcium concentration, reactive oxygen species, malondialdehyde, and glutathione disulfide (GSSG), and increases levels of superoxide dismutase, catalase, glutathione, and GSH/GSSG. Further, [6]-gingerol improved ISO-induced morphological pathologies, inhibited inflammation and apoptosis, and suppressed the toll-like receptor-4 (TLR4)/mitogen-activated protein kinases (MAPKs)/nuclear factor κB (NF-κB) signaling pathways.

CONCLUSION

The protective effect of [6]-gingerol in mice with ISO-induced myocardial fibrosis may be related to the inhibition of oxidative stress, inflammation, and apoptosis, potentially through the TLR4/MAPKs/NF-κB signaling pathway.

Effects of various doses of atorvastatin on vascular endothelial cell apoptosis and autophagy in vitro

Atorvastatin (Lipitor™) is a lipid‑lowering agent that is widely used in the treatment of cardiovascular diseases. Previous research has largely focused on its cholesterol‑lowering effects; however, a limited number of studies have investigated the actions of atorvastatin on vascular endothelial cells. In the present study, the effects of various doses of atorvastatin were investigated on human umbilical vein endothelial cells (HUVECs). HUVECs were treated with various concentrations of atorvastatin in serum‑free or serum‑containing medium, and alterations in HUVEC morphology were observed. Cell survival and necrosis rates were evaluated using sulforhodamine B and lactate dehydrogenase assays, respectively. In addition, the protein expression levels of cellular apoptosis and autophagy markers were detected using western blot analysis. The results revealed that HUVEC morphology was altered following treatment with various concentrations of atorvastatin. In addition, autophagy was demonstrated to be induced by atorvastatin treatment at all concentrations, whereas high concentrations appeared to induce apoptosis and suppress the survival of HUVECs. In conclusion, the results of the present study suggested that various doses of atorvastatin may exert differential effects on HUVECs, and high doses may suppress angiogenesis. Therefore, atorvastatin may present a novel potential anti‑tumor therapeutic strategy. However, further studies are required to fully elucidate the association between the dose of atorvastatin and its clinical outcome.

Recent Advances in Endothelial Progenitor Cells Toward Their Use in Clinical Translation

Since the discovery of Endothelial Progenitor Cells (EPC) by Asahara and colleagues in 1997, an increasing number of preclinical studies have shown that EPC based therapy is feasible, safe, and efficacious in multiple disease states. Subsequently, this has led to several, mainly early phase, clinical trials demonstrating the feasibility and safety profile of EPC therapy, with the suggestion of efficacy in several conditions including ischemic heart disease, pulmonary arterial hypertension and decompensated liver cirrhosis. Despite the use of the common term “EPC,” the characteristics, manufacturing methods and subset of the cell type used in these studies often vary significantly, rendering clinical translation challenging. It has recently been acknowledged that the true EPC is the endothelial colony forming cells (ECFC). The objective of this review was to summarize and critically appraise the registered and published clinical studies using the term “EPC,” which encompasses a heterogeneous cell population, as a therapeutic agent. Furthermore, the preclinical data using ECFC from the PubMed and Web of Science databases were searched and analyzed. We noted that despite the promising effect of ECFC on vascular regeneration, no clinical study has stemmed from these preclinical studies. We showed that there is a lack of information registered on www.clinicaltrials.gov for EPC clinical trials, specifically on cell culture methods. We also highlighted the importance of a detailed definition of the cell type used in EPC clinical trials to facilitate comparisons between trials and better understanding of the potential clinical benefit of EPC based therapy. We concluded our review by discussing the potential and limitations of EPC based therapy in clinical settings.

Endothelial cell senescence in aging-related vascular dysfunction

Increased cardiovascular disease in aging is partly a consequence of the vascular endothelial cell (EC) senescence and associated vascular dysfunction. In this contest, EC senescence is a pathophysiological process of structural and functional changes including dysregulation of vascular tone, increased endothelium permeability, arterial stiffness, impairment of angiogenesis and vascular repair, and a reduction of EC mitochondrial biogenesis. Dysregulation of cell cycle, oxidative stress, altered calcium signaling, hyperuricemia, and vascular inflammation have been implicated in the development and progression of EC senescence and vascular disease in aging. A number of abnormal molecular pathways are associated with these underlying pathophysiological changes including Sirtuin 1, Klotho, fibroblast growth factor 21, and activation of the renin angiotensin-aldosterone system. However, the molecular mechanisms of EC senescence and associated vascular impairment in aging are not completely understood. This review provides a contemporary update on molecular mechanisms, pathophysiological events, as well functional changes in EC senescence and age-associated cardiovascular disease. This article is part of a Special Issue entitled: Genetic and epigenetic regulation of aging and longevity edited by Jun Ren & Megan Yingmei Zhang.

Editor's Highlight: Modifying Role of Endothelial Function Gene Variants on the Association of Long-Term PM2.5 Exposure With Blood DNA Methylation Age: The VA Normative Aging Study

Recent studies have reported robust associations of long-term PM2.5 exposure with DNA methylation-based measures of aging; yet, the molecular implications of these relationships remain poorly understood. We evaluated if genetic variation in 3 biological pathways implicated in PM2.5-related disease-oxidative stress, endothelial function, and metal processing-could modify the effect of PM2.5 on DNAm-age, one prominent DNA methylation-based measure of biological age. This analysis was based on 552 individuals from the Normative Aging Study with at least one visit between 2000 and 2011 (n = 940 visits). A genetic-score approach was used to calculate aging-risk variant scores for endothelial function, oxidative stress, and metal processing pathways. One-year PM2.5 and PM2.5 component (sulfate and ammonium) levels at participants' addresses were estimated using the GEOS-chem transport model. Blood DNAm-age was calculated using CpG sites on the Illumina HumanMethylation450 BeadChip. In fully-adjusted linear mixed-effects models, the effects of sulfate on DNAm-age (in years) were greater in individuals with high aging-risk endothelial function variant scores when compared with individuals with low aging-risk endothelial function variant scores (Pinteraction = 0.0007; βHigh = 1.09, 95% CIHigh: 0.70, 1.48; βLow = 0.40, 95% CILow: 0.14, 0.67). Similar trends were observed in fully adjusted models of ammonium and total PM2.5 alone. No effect modification was observed by oxidative stress and metal processing variant scores. Secondary analyses revealed significant associations of serum endothelial markers, intercellular adhesion molecule-1 (β = 0.01, 95% CI: 0.002, 0.012) and vascular cell adhesion molecule-1 (β = 0.002, 95% CI: 0.0005, 0.0026), with DNAm-age. Our results add novel evidence that endothelial physiology may be important to DNAm-age relationships, but further research is required to establish their generalizability.

Reduction of Vascular Inflammation, LDL-C, or Both for the Protection from Cardiovascular Events?

BACKGROUND

Low density lipoprotein cholesterol (LDL-C) and low grade arterial inflammation are key pathogenic factors for atherosclerosis and its manifestation, cardiovascular disease (CVD).

OBJECTIVE

In this narrative review we assessed if decreasing LDL-C levels or inflammation or both is more effective in reducing CVD events.

RESULTS

In the Scandinavian Simvastatin Survival Study (4S), all statin trials of the 90s' and the Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk (FOURIER) the benefit came from the LDL-C reduction. In the GREak and Atorvastatin Coronary heart disease Evaluation (GREACE), the Treating to New Targets (TNT), and the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trials both mechanisms in combination produced significant benefits. In the Atorvastatin for Reduction of MYocardial Damage during Angioplasty (ARMYDA) trials and the Canakinumab Antiinflammatory Thrombosis Outcome Study (CANTOS) with a human antibody targeting IL-1β with no lipid lowering effect, the reduction in arterial inflammation played the only beneficial role because there was no change in lipids levels.

CONCLUSION

Both LDL-C and inflammation reduction are beneficial to the reduction of CVD risk. However, canakinumab is a very expensive drug that only induced a 15% reduction in CVD events, thus drastically reducing the possibility for it to be used in clinical practice. Besides, canakinumab is associated with increased infections, some fatal. A potent statin with anti-inflammatory effects is probably the best choice for the majority of those needing hypolipidaemic drug therapy.

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

Stem cells have the potential to differentiate into cardiovascular cell lineages and to stimulate tissue regeneration in a paracrine/autocrine manner; thus, they have been extensively studied as candidate cell sources for cardiovascular regeneration. Several preclinical and clinical studies addressing the therapeutic potential of endothelial progenitor cells (EPCs) and cardiac progenitor cells (CPCs) in cardiovascular diseases have been performed. For instance, autologous EPC transplantation and EPC mobilization through pharmacological agents contributed to vascular repair and neovascularization in different animal models of limb ischemia and myocardial infarction. Also, CPC administration and in situ stimulation of resident CPCs have been shown to improve myocardial survival and function in experimental models of ischemic heart disease. However, clinical studies using EPC- and CPC-based therapeutic approaches have produced mixed results. In this regard, intracoronary, intra-myocardial or intramuscular injection of either bone marrow-derived or peripheral blood progenitor cells has improved pathological features of tissue ischemia in humans, despite modest or no clinical benefit has been observed in most cases. Also, the intriguing scientific background surrounding the potential clinical applications of EPC capture stenting is still waiting for a confirmatory proof. Moreover, clinical findings on the efficacy of CPC-based cell therapy in heart diseases are still very preliminary and based on small-size studies. Despite promising evidence, widespread clinical application of both EPCs and CPCs remains delayed due to several unresolved issues. The present review provides a summary of the different applications of EPCs and CPCs for cardiovascular cell therapy and underlies their advantages and limitations.

The acute impact of high-dose lipid-lowering treatment on endothelial progenitor cells in patients with coronary artery disease-The REMEDY-EPC early substudy

RATIONALE AND OBJECTIVE

Endothelial progenitor cells (EPCs) play a role in vascular repair, while circulating endothelial cells (CECs) are biomarkers of vascular damage and regeneration. Statins may promote EPC/CEC mobilization in the peripheral blood. We evaluated whether pre-procedural exposure to different lipid-lowering drugs (statins±ezetimibe) can acutely increase levels/activity of EPCs/CECs in patients with stable coronary artery disease (CAD).

METHODS

In a planned sub-analysis of the Rosuvastatin For REduction Of Myocardial DamagE During Coronary AngioplastY (REMEDY) trial, 38 patients with stable CAD on chronic low-dose statin therapy were randomized, in a double-blind, placebo-controlled design, into 4 groups before PCI: i. placebo (n = 11); ii. atorvastatin (80 mg+40 mg, n = 9); iii. rosuvastatin (40 mg twice, n = 9); and iv. rosuvastatin (5 mg) and ezetimibe (10 mg) twice, (n = 9). At baseline and 24 h after treatment-before PCI-, patients underwent blinded analyses of EPCs [colony forming units-endothelial cells (CFU-ECs), endothelial colony-forming cells (ECFCs) and tubulization activity] and CECs in peripheral blood.

RESULTS

We found no significant treatment effects on parameters investigated such as number of CECs [Median (IQR): i. 0(0), ii. 4.5(27), iii. 1.9(2.3), iv. 1.9(2.3)], CFU-ECs [Median (IQR): i. 27(11), ii. 19(31), iii. 47(36), iv. 30(98)], and ECFCs [Median (IQR): i. 86(84), ii. 7(84), iii. 8/(42.5), iv. 5(2)], as well as tubulization activity [total tubuli (well), Median (IQR): i. 19(7), ii. 5(4), iii. 25(13), iv. 15(24)].

CONCLUSIONS

In this study, we found no evidence of acute changes in levels or activity of EPCs and CECs after high-dose lipid-lowering therapy in stable CAD patients.

Rosuvastatin for Reduction of Myocardial Damage during Coronary Angioplasty - the Remedy Trial

BACKGROUND

Periprocedural myocardial infarction (MI) is a frequent complication of percutaneous coronary intervention (PCI). Statins might reduce its incidence. The aims of the present study are to assess whether such benefit is a class-effect or whether differences exist between various lipid-lowering strategies and whether cardioprotection is exerted by increasing circulating endothelial progenitor cells (EPCs).

METHODS

The REMEDY study will enroll a total of 1080 patients submitted to elective PCI. Eligible patients will be randomized into 4 groups: 1) placebo; 2) atorvastatin (80 mg + 40 mg before PCI); 3) rosuvastatin (40 mg twice before PCI); and 4) rosuvastatin (5 mg) and ezetimibe (10 mg) twice before PCI. Peri-procedural MI is defined as an elevation of markers of cardiac injury (either CK-MB or troponin I or T) values >5x the upper reference limit estimated at the 99th percentile of the normal distribution, or a rise >20 % in case of baseline values already elevated. EPCs will be assessed before, at 24 h and - in a subset of diabetic patients - at 3 months after PCI (EPC-substudies). The primary endpoint of the main REMEDY study is the rate of peri-procedural MI in each of the 4 treatment arms. Secondary endpoints are the combined occurrence of 1-month major adverse events (MACE, including death, MI, or the need for unplanned revascularization); and any post-procedural increase in serum creatinine. Endpoints of the EPC-substudies are the impact of tested regimens on 1) early (24-h) and 3-month EPC levels and functional activity; 2) stent strut re-endothelialization and neointimal hyperplasia; 3) 1-year MACE. REMEDY will add important information on the cardioprotective effects of statins after PCI.

Progenitor Cells for Arterial Repair: Incremental Advancements towards Therapeutic Reality

Coronary revascularization remains the standard treatment for obstructive coronary artery disease and can be accomplished by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery. Considerable advances have rendered PCI the most common form of revascularization and improved clinical outcomes. However, numerous challenges to modern PCI remain, namely, in-stent restenosis and stent thrombosis, underscoring the importance of understanding the vessel wall response to injury to identify targets for intervention. Among recent promising discoveries, endothelial progenitor cells (EPCs) have garnered considerable interest given an increasing appreciation of their role in vascular homeostasis and their ability to promote vascular repair after stent placement. Circulating EPC numbers have been inversely correlated with cardiovascular risk, while administration of EPCs in humans has demonstrated improved clinical outcomes. Despite these encouraging results, however, advancing EPCs as a therapeutic modality has been hampered by a fundamental roadblock: what constitutes an EPC? We review current definitions and sources of EPCs as well as the proposed mechanisms of EPC-mediated vascular repair. Additionally, we discuss the current state of EPCs as therapeutic agents, focusing on endogenous augmentation and transplantation.

Human cells involved in atherosclerosis have a sex

The influence of sex has been largely described in cardiovascular diseases. Atherosclerosis is a complex process that involves many cell types such as vessel cells, immune cells and endothelial progenitor cells; however, many, if not all, studies do not report the sex of the cells. This review focuses on sex differences in human cells involved in the atherosclerotic process, emphasizing the role of sex hormones. Furthermore, we report sex differences and issues related to the processes that determine the fate of the cells such as apoptotic and autophagic mechanisms. The analysis of the data reveals that there are still many gaps in our knowledge regarding sex influences in atherosclerosis, largely for the cell types that have not been well studied, stressing the urgent need for a clear definition of experimental conditions and the inclusion of both sexes in preclinical studies.