Atorvastatin treatment improves endothelial function through endothelial progenitor cells mobilization in ischemic heart failure patients

Endothelial progenitor cells for cellular angiogenesis and repair: lessons learned from experimental animal models

Stem/progenitor cell-based therapy has been extensively studied for angiomyogenic repair of the ischemic heart by regeneration of the damaged myocytes and neovascularization of the ischemic tissue through biological bypassing. Given their inherent ability to assume functionally competent endothelial phenotype and release of broad array of proangiogenic cytokines, endothelial progenitor cells (EPCs)-based therapy is deemed as most appropriate for vaculogenesis in the ischemic heart. Emulating the natural repair process that encompasses mobilization and homing-in of the bone marrow and peripheral blood EPCs, their reparability has been extensively studied in the animal models of myocardial ischemia with encouraging results. Our literature review is a compilation of the lessons learned from the use of EPCs in experimental animal models with emphasis on the in vitro manipulation and delivery strategies to enhance their retention, survival and functioning post-engraftment in the heart.

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.

Intrauterine growth restriction-induced deleterious adaptations in endothelial progenitor cells: possible mechanism to impair endothelial function

Intrauterine growth restriction (IUGR) can induce deleterious changes in the modulatory ability of the vascular endothelium, contributing to an increased risk of developing cardiovascular diseases in the long term. However, the mechanisms involved are not fully understood. Emerging evidence has suggested the potential role of endothelial progenitor cells (EPCs) in vascular health and repair. Therefore, we aimed to evaluate the effects of IUGR on vascular reactivity and EPCs derived from the peripheral blood (PB) and bone marrow (BM) in vitro. Pregnant Wistar rats were fed an ad libitum diet (control group) or 50% of the ad libitum diet (restricted group) throughout gestation. We determined vascular reactivity, nitric oxide (NO) concentration, and endothelial nitric oxide synthase (eNOS) protein expression by evaluating the thoracic aorta of adult male offspring from both groups (aged: 19-20 weeks). Moreover, the amount, functional capacity, and senescence of EPCs were assessed in vitro. Our results indicated that IUGR reduced vasodilation via acetylcholine in aorta rings, decreased NO levels, and increased eNOS phosphorylation at Thr495. The amount of EPCs was similar between both groups; however, IUGR decreased the functional capacity of EPCs from the PB and BM. Furthermore, the senescence process was accelerated in BM-derived EPCs from IUGR rats. In summary, our findings demonstrated the deleterious changes in EPCs from IUGR rats, such as reduced EPC function and accelerated senescence in vitro. These findings may contribute towards elucidating the possible mechanisms involved in endothelial dysfunction induced by fetal programming.

Moderate-dose atorvastatin improves arterial endothelial function in patients with angina pectoris and normal coronary angiogram: a pilot study

INTRODUCTION

Endothelial dysfunction could contribute to the pathophysiology of angina pectoris (AP) in patients with normal coronary angiograms. Besides lipid-lowering effects, statins exert pleiotropic effects including improving endothelial function.

MATERIAL AND METHODS

Our double-blind study included 58 patients with AP, noninvasively confirmed myocardial ischemia and a normal coronary angiogram. The effect of once-daily 20 mg atorvastatin (A) was compared with placebo (P) for 6 months. Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery, and microcirculation by peripheral arterial tonometry (EndoPAT) measuring the reactive hyperemia index (RHI), indicating microcirculatory endothelial function, and the augmentation index (AI), an indicator of arterial stiffness. The impact of AP on the quality of life was monitored using the Seattle Angina Questionnaire (SAQ).

RESULTS

Brachial artery endothelial dysfunction was found in 91.4% of patients at study entry, and subnormal RHI in 41%. Group A showed an improvement of FMD compared with group P, both at 3 and 6 months (+120.8% vs. -21.2%, and +70.8% vs. -1.9%, respectively, p < 0.001). No difference was detected in the RHI. Rate-normalized AI showed an improvement (-114.49% group A vs. -30.77% group P, p = 0.077), although the differences between the groups were not significant. According to the SAQ, an improvement was found in almost all observed variables with the exception of the issue of quality of life (QoL), where patients in both groups assessed their QoL at the control study visits as poorer compared with baseline.

CONCLUSIONS

Moderate-dose atorvastatin therapy improves endothelial function of large conduit arteries in patients with AP and a normal coronary angiogram, which probably reflects positive effects on coronary artery endothelial function. No effect was found with vascular effects at the level of the peripheral microcirculation.

Rationale for the use of statins in liver disease

The evolution of chronic liver injuries from benign and manageable dysfunction to life threatening end-stage liver disease with severe complications renders chronic liver disease a global health burden. Because of the lack of effective medication, transplantation remains the only and final curative option for end-stage liver disease. Since the demand for organ transplants by far exceeds the supply, other treatment options are urgently required to prevent progression and improve end-stage liver disease. Statins are primarily cholesterol-lowering drugs used for primary or secondary prevention of cardiovascular diseases. In addition to the primary effect, statins act beneficially through different pleiotropic mechanisms on inflammation, fibrosis, endothelial function, thrombosis, and coagulation to improve chronic liver diseases. However, concerns remain about the efficacy and safety of statin treatment because of their potential hepatotoxic risks, and as of now, these risks impede broader use of statins in the treatment of chronic liver diseases. The aim of this review is to comprehensively describe the mechanisms by which statins improve prospects for different chronic liver diseases with special focus on the pathophysiological rationale and the clinical experience of statin use in the treatment of liver diseases.

The future of pleiotropic therapy in heart failure. Lessons from the benefits of exercise training on endothelial function

A novel generation of drugs is introduced in the treatment of heart failure (HF). These drugs, including phosphodiesterase-5 inhibitors, guanylate cyclase stimulators and activators, share the feature that their action is either endothelial-mediated or substitutes for endothelial pathways, in particular the nitric oxide-cyclic guanosine monophosphate pathway, thereby influencing homeostatic balances in virtually each organ system in a pleiotropic fashion. Unfortunately, recent clinical trials with some of these drugs have shown disappointing results, at least in the setting of HF with a preserved ejection fraction. This suggests that their clinical use may require approaches that diverge from traditional pharmacological approaches, the latter often titrated on the effects of drugs on haemodynamic parameters or single biomarkers. In this paper we preconize that HF drugs with an endothelial profile should be applied conform to principles of endothelial physiology and systems pharmacology. This type of drug therapy should be viewed as a systems physio-pharmacological intervention and its clinical use accustomed to systems pharmacological principles, comparable to the systemic endothelial-mediated benefits induced by exercise training in HF. We will review the actions of these drugs and define criteria to which trials with these drugs should comply in order to increase chances of success.

Atorvastatin enhances endothelial cell function in posttransplant poor graft function

Dysfunctional BM EPCs were found in subjects with PGF postallotransplant. BM EPCs from subjects with PGF were enhanced by atorvastatin through downregulation of the p38 MAPK pathway.

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.

Therapeutic Potential of Stem Cells Strategy for Cardiovascular Diseases

Despite development of medicine, cardiovascular diseases (CVDs) are still the leading cause of mortality and morbidity worldwide. Over the past 10 years, various stem cells have been utilized in therapeutic strategies for the treatment of CVDs. CVDs are characterized by a broad range of pathological reactions including inflammation, necrosis, hyperplasia, and hypertrophy. However, the causes of CVDs are still unclear. While there is a limit to the currently available target-dependent treatments, the therapeutic potential of stem cells is very attractive for the treatment of CVDs because of their paracrine effects, anti-inflammatory activity, and immunomodulatory capacity. Various studies have recently reported increased therapeutic potential of transplantation of microRNA- (miRNA-) overexpressing stem cells or small-molecule-treated cells. In addition to treatment with drugs or overexpressed miRNA in stem cells, stem cell-derived extracellular vesicles also have therapeutic potential because they can deliver the stem cell-specific RNA and protein into the host cell, thereby improving cell viability. Here, we reported the state of stem cell-based therapy for the treatment of CVDs and the potential for cell-free based therapy.

Atorvastatin alleviates cardiomyocyte apoptosis by suppressing TRB3 induced by acute myocardial infarction and hypoxia

BACKGROUND/PURPOSE

TRB3 (tribbles 3), an apoptosis-regulated gene, increases during endoplasmic reticulum stress. Hypoxia can induce inflammatory mediators and apoptosis in cardiomyocytes. However, the expression of TRB3 in cardiomyocyte apoptosis under hypoxia is not thoroughly known. We investigated the regulation mechanism of TRB3 expression and apoptosis induced by hypoxia in cardiomyocytes.

METHODS

An in vivo model of acute myocardial infarction (AMI) was applied in adult Wistar rats to induce myocardial hypoxia. Rat neonatal cardiomyocytes were subjected to 2.5% O₂ to induce hypoxia.

RESULTS

The expression of TRB3 was evaluated in cultured rat neonatal cardiomyocytes subjected to hypoxia. Hypoxia significantly enhanced TRB3 protein and mRNA expression. Adding c-jun N-terminal kinase (JNK) inhibitor SP600125, JNK small interfering RNA (siRNA), tumor necrosis factor-α (TNF-α) antibody, and atorvastatin 30 minutes before hypoxia reversed the induction of TRB3 protein. A gel-shift assay showed the DNA-binding activity of growth arrest and DNA damage-inducible gene 153 (GADD153), which increased after hypoxia. Hypoxia increased, whereas the TRB3-mut plasmid, SP600125, and TNF-α antibody abolished the hypoxia-induced TRB3 promoter activity. Hypoxia increased the secretion of TNF-α from cardiomyocytes. Exogenous administration of TNF-α recombinant protein to the cardiomyocytes without hypoxia increased TRB3 protein expression, similar to that observed after hypoxia. Hypoxia-induced cardiomyocyte apoptosis is inhibited by TRB3 siRNA, the TNF-α antibody, and atorvastatin. Atorvastatin reduced the TRB3 expression and cardiomyocyte apoptosis induced by AMI. Hypoxia induces TRB3 through TNF-α, JNK, and the GADD153 pathway.

CONCLUSION

Treatment of atorvastatin inhibits the expression of TRB3 and cardiomyocyte apoptosis induced by AMI and hypoxia.

The Acute Impact of Different Types of Aerobic Exercise on Arterial Wave Reflections and Inflammation

Objectives: Whilst physical activity is linked to cardiovascular health, it has lately been recognized that different types of exercise exert diverse effects on the cardiovascular system. Therefore, we investigated the acute effects of continuous moderate-intensity aerobic exercise (CAE) and high-intensity interval aerobic exercise (hIAE) on arterial function and inflammation. Methods: Twenty healthy men (mean age 22.6 ± 3.3 years) were recruited in this crossover study. Each of the 20 volunteers participated in two separate sessions (hIAE and CAE). The augmentation index (AIx) of aortic pressure waveforms and serum levels of interleukin-17 (IL-17) were measured before and after each exercise session. Results: There were no significant differences in baseline hemodynamic and inflammatory measurements before CAE and hIAE. Compared to baseline, AIx was significantly improved after CAE (p = 0.04), while there was no significant change after hIAE (p = 0.65). Serum levels of IL-17 were significantly elevated after CAE (p = 0.042), while hIAE had no significant effect on IL-17 levels (p = 0.47). Interestingly, there was an inverse association between the elevation of IL-17 levels and the AIx improvement after CAE (p = 0.05). Conclusion: These findings provide additional evidence concerning the cardiovascular effects of different types of exercise training through modification of peripheral hemodynamics and the inflammatory process.

Towards a biofunctionalized vascular prosthesis: immune cell trapping via a growth factor receptor

To improve the clinical performance of vascular prostheses, which is inacceptably low for implants with small diameters (< 6 mm), biofunctionalization of synthetic implants by endothelialization has become a major, although still unreached, aim. In order to be able to recruit native endothelial progenitor cells (EPCs) to luminal implant surfaces from the blood stream, we generated monoclonal antibodies against the EPC-specific vascular endothelial growth factor receptor 2 (VEGFR-2). Employing the very efficient genetic immunization strategy, > 10 000 hybridoma clones were generated. Screening with various deletion mutants of VEGFR-2, 49 highly-specific monoclonal antibodies (mAbs) covering all seven Ig domains of VEGFR-2 were selected. mAb 9H10 was characterized in detail. Once immobilized on synthetic surfaces, mAb 9H10 allowed, within min, nearly 100-fold enrichment of VEGFR-2-expressing cells under continuous flow conditions. Cell trapping was cell-type specific and essentially not affected by competing VEGFR-2-negative cells. To exclude that the antibody would adversely modify receptor responses, four different in vitro assays were employed. Cell proliferation, angiogenic tube formation, acetylated low-density lipoprotein uptake and VEGFR-2 phosphorylation remained unaffected, suggesting that the antibody did not interfere with the receptor functioning of human umbilical vascular endothelial cells. The molecular and cellular characteristics make the selected monoclonal antibody a very promising tool for the biofunctionalization of vascular implants. Copyright © 2016 John Wiley & Sons, Ltd.

Modulation of microRNA Expression in Subjects with Metabolic Syndrome and Decrease of Cholesterol Efflux from Macrophages via microRNA-33-Mediated Attenuation of ATP-Binding Cassette Transporter A1 Expression by Statins

Metabolic syndrome (MetS) is a complicated health problem that encompasses a variety of metabolic disorders. In this study, we analyzed the relationship between the major biochemical parameters associated with MetS and circulating levels of microRNA (miR)-33, miR-103, and miR-155. We found that miRNA-33 levels were positively correlated with levels of fasting blood glucose, glycosylated hemoglobin A1c, total cholesterol, LDL-cholesterol, and triacylglycerol, but negatively correlated with HDL-cholesterol levels. In the cellular study, miR-33 levels were increased in macrophages treated with high glucose and cholesterol-lowering drugs atorvastatin and pitavastatin. miR-33 has been reported to play an essential role in cholesterol homeostasis through ATP-binding cassette transporter A1 (ABCA1) regulation and reverse cholesterol transport. However, the molecular mechanism underlying the linkage between miR-33 and statin treatment remains unclear. In the present study, we investigated whether atorvastatin and pitavastatin exert their functions through the modulation of miR-33 and ABCA1-mediated cholesterol efflux from macrophages. The results showed that treatment of the statins up-regulated miR-33 expression, but down-regulated ABCA1 mRNA levels in RAW264.7 cells and bone marrow-derived macrophages. Statin-mediated ABCA1 regulation occurs at the post-transcriptional level through targeting of the 3′-UTR of the ABCA1 transcript by miR-33. Additionally, we found significant down-regulation of ABCA1 protein expression in macrophages treated with statins. Finally, we showed that high glucose and statin treatment significantly suppressed cholesterol efflux from macrophages. These findings have highlighted the complexity of statins, which may exert detrimental effects on metabolic abnormalities through regulation of miR-33 target genes.

Concise Review: Endothelial Progenitor Cells in Regenerative Medicine: Applications and Challenges

Endothelial progenitor cells (EPCs) are currently being studied as candidate cell sources for revascularization strategies. Significant advances have been made in understanding the biology of EPCs, and preclinical studies have demonstrated the vasculogenic, angiogenic, and beneficial paracrine effects of transplanted EPCs in the treatment of ischemic diseases. Despite these promising results, widespread clinical acceptance of EPCs for clinical therapies remains hampered by several challenges. The present study provides a concise summary of the different EPC populations being studied for ischemic therapies and their known roles in the healing of ischemic tissues. The challenges and issues surrounding the use of EPCs and the current strategies being developed to improve the harvest efficiency and functionality of EPCs for application in regenerative medicine are discussed.

SIGNIFICANCE

Endothelial progenitor cells (EPCs) have immense clinical value for cardiovascular therapies. The present study provides a concise description of the EPC subpopulations being evaluated for clinical applications. The current major lines of investigation involving preclinical and clinical evaluations of EPCs are discussed, and significant gaps limiting the translation of EPCs are highlighted. The present report could be useful for clinicians and clinical researchers with interests in ischemic therapy and for basic scientists working in the related fields of tissue engineering and regenerative medicine.

Endothelial progenitor cells (EPCs) in ageing and age-related diseases: How currently available treatment modalities affect EPC biology, atherosclerosis, and cardiovascular outcomes

Endothelial progenitor cells (EPCs) are mononuclear cells that circulate in the blood and are derived from different tissues, expressing cell surface markers that are similar to mature endothelial cells. The discovery of EPCs has lead to new insights in vascular repair and atherosclerosis and also a new theory for ageing. EPCs from the bone marrow and some other organs aid in vascular repair by migrating to distant vessels where they differentiate into mature endothelial cells and replace old and injured endothelial cells. The ability of EPCs to repair vascular damage depends on their number and functionality. Currently marketed drugs used in a variety of diseases can modulate these characteristics. In this review, the effect of currently available treatment options for cardiovascular and metabolic disorders on EPC biology will be discussed. The various EPC-based therapies that will be discussed include lipid-lowering agents, antihypertensive agents, antidiabetic drugs, phosphodiesteraze inhibitors, hormones, as well as EPC capturing stents.

Inflammatory cytokines in atherosclerosis: current therapeutic approaches

The notion of atherosclerosis as a chronic inflammatory disease has intensified research on the role of cytokines and the way these molecules act and interact to initiate and sustain inflammation in the microenvironment of an atherosclerotic plaque. Cytokines are expressed by all types of cells involved in the pathogenesis of atherosclerosis, act on a variety of targets exerting multiple effects, and are largely responsible for the crosstalk among endothelial, smooth muscle cells, leucocytes, and other vascular residing cells. It is now understood that widely used drugs such as statins, aspirin, methotrexate, and colchicine act in an immunomodulatory way that may beneficially affect atherogenesis and/or cardiovascular disease progression. Moreover, advancement in pharmaceutical design has enabled the production of highly specific antibodies against key molecules involved in the perpetuation of the inflammatory cascade, raising hope for advances in the treatment of atherosclerosis. This review describes the actions and effects of these agents, their potential clinical significance, and future prospects.

Involvement of NADPH oxidases and non-muscle myosin light chain in senescence of endothelial progenitor cells in hyperlipidemia

NADPH oxidase (NOX)-derived reactive oxygen species (ROS) is involved in endothelial dysfunction of hyperlipidemia, and non-muscle myosin regulatory light chain (nmMLC20) is reported to have a transcriptional function in regulation of gene expression. The purposes of this study are to determine whether NOX-derived ROS can promote endothelial progenitor cell (EPC) senescence and whether nmMLC20 can regulate NOX expression through a phosphorylation-dependent manner. The rats were subjected to 8 weeks of high-fat diet feeding to establish a hyperlipidemic model, which showed an increase in plasma lipids and the accelerated senescence and reduced number of circulating EPCs, accompanied by an increase in myosin light chain kinase (MLCK) and NOX activities, p-nmMLC20 level, NOX (NOX2, NOX4) expression, and H2O2 content. Next, EPCs isolated from normal rats were incubated with ox-LDL (100 μg/mL) for 24 h to establish a senescent model in vitro. Consistent with our in vivo findings, ox-LDL treatment increased the senescence of EPCs concomitant with an increase in MLCK and NOX activities, p-nmMLC20 level (in total or nuclear proteins), NOX expression, and H2O2 content; these phenomena were reversed by MLCK inhibitor. NOX inhibitor achieved similar results to that of MLCK inhibitor except that there is no effect on MLCK activity and p-nmMLC20 level. Furthermore, knockdown of nmMLC20, NOX2, or NOX4 led to a down-regulation in NOX and a reduction in ox-LDL-induced EPC senescence. These results suggest that NOX-derived ROS promotes the senescence of circulating EPCs in hyperlipidemia and nmMLC20 may play a transcriptional role in the upregulation of NOX through a phosphorylation-dependent manner.

Vascular Ageing and Exercise: Focus on Cellular Reparative Processes

Ageing is associated with an increased risk of developing noncommunicable diseases (NCDs), such as diabetes and cardiovascular disease (CVD). The increased risk can be attributable to increased prolonged exposure to oxidative stress. Often, CVD is preceded by endothelial dysfunction, which carries with it a proatherothrombotic phenotype. Endothelial senescence and reduced production and release of nitric oxide (NO) are associated with “vascular ageing” and are often accompanied by a reduced ability for the body to repair vascular damage, termed “reendothelialization.” Exercise has been repeatedly shown to confer protection against CVD and diabetes risk and incidence. Regular exercise promotes endothelial function and can prevent endothelial senescence, often through a reduction in oxidative stress. Recently, endothelial precursors, endothelial progenitor cells (EPC), have been shown to repair damaged endothelium, and reduced circulating number and/or function of these cells is associated with ageing. Exercise can modulate both number and function of these cells to promote endothelial homeostasis. In this review we look at the effects of advancing age on the endothelium and these endothelial precursors and how exercise appears to offset this “vascular ageing” process.

Enhancing endothelial progenitor cell for clinical use

Circulating endothelial progenitor cells (EPCs) have been demonstrated to correlate negatively with vascular endothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

Exercise intolerance in heart failure with preserved ejection fraction: more than a heart problem

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF in older adults, and is increasing in prevalence as the population ages. Furthermore, HFpEF is increasing out of proportion to HF with reduced EF (HFrEF), and its prognosis is worsening while that of HFrEF is improving. Despite the importance of HFpEF, our understanding of its pathophysiology is incomplete, and optimal treatment remains largely undefined. A cardinal feature of HFpEF is reduced exercise tolerance, which correlates with symptoms as well as reduced quality of life. The traditional concepts of exercise limitations have focused on central dysfunction related to poor cardiac pump function. However, the mechanisms are not exclusive to the heart and lungs, and the understanding of the pathophysiology of this disease has evolved. Substantial attention has focused on defining the central versus peripheral mechanisms underlying the reduced functional capacity and exercise tolerance among patients with HF. In fact, physical training can improve exercise tolerance via peripheral adaptive mechanisms even in the absence of favorable central hemodynamic function. In addition, the drug trials performed to date in HFpEF that have focused on influencing cardiovascular function have not improved exercise capacity. This suggests that peripheral limitations may play a significant role in HF limiting exercise tolerance, a hallmark feature of HFpEF.