Role of endothelial progenitor cells in the beneficial effects of physical exercise on atherosclerosis and 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.

Endothelial progenitor cell mobilization based on exercise volume in patients with cardiovascular disease and healthy individuals: a systematic review and meta-analysis

Endothelial progenitor cells (EPCs) play a vital role in protecting endothelial dysfunction and cardiovascular disease (CVD). Physical exercise stimulates the mobilization of EPCs, and along with vascular endothelial growth factor (VEGF), promotes EPC differentiation, and contributes to vasculogenesis. The present meta-analysis examines the exercise-induced EPC mobilization and has an impact on VEGF in patients with CVD and healthy individuals. Database research was conducted (PubMed, EMBASE, Cochrane Library of Controlled Trials) by using an appropriate algorithm to indicate the exercise-induced EPC mobilization studies. Eligibility criteria included EPC measurements following exercise in patients with CVD and healthy individuals. A continuous random effect model meta-analysis (PROSPERO-CRD42019128122) was used to calculate mean differences in EPCs (between baseline and post-exercise values or between an experimental and control group). A total of 1460 participants (36 studies) were identified. Data are presented as standard mean difference (Std.MD) and 95% confidence interval (95% CI). Aerobic training stimulates the mobilization of EPCs and increases VEGF in patients with CVD (EPCs: Std.MD: 1.23, 95% CI: 0.70-1.76; VEGF: Std.MD: 0.76, 95% CI:0.16-1.35) and healthy individuals (EPCs: Std.MD: 1.11, 95% CI:0.53-1.69; VEGF: Std.MD: 0.75, 95% CI: 0.01-1.48). Acute aerobic exercise (Std.MD: 1.40, 95% CI: 1.00-1.80) and resistance exercise (Std.MD: 0.46, 95%CI: 0.10-0.82) enhance EPC numbers in healthy individuals. Combined aerobic and resistance training increases EPC mobilization (Std.MD:1.84, 95% CI: 1.03-2.64) in patients with CVD. Adequate exercise volume (>60%VO_2max >30 min; P = 0.00001) yields desirable results. Our meta-analysis supports the findings of the literature. Exercise volume is required to obtain clinically significant results. Continuous exercise training of high-to-moderate intensity with adequate duration as well as combined training with aerobic and resistance exercise stimulates EPC mobilization and increases VEGF in patients with CVD and healthy individuals.

Effect of traditional Chinese exercise on abnormal lipid metabolism in patients with atherosclerosis: a protocol for meta-analysis of randomised controlled trials

INTRODUCTION

Atherosclerosis (AS) is an abnormal response within the vessel wall to endothelial dysfunction and inflammatory cellular processes. Taijiquan exercise as a moderate-intensity aerobic exercise can control or reverse AS by gradually reducing the deposition of cholesterol on the walls of blood vessels. Similarly, performing Baduanjin exercise, Liuzijue Qigong, Wuqinxi exercise and Yijinjing exercise has been found to have a positive effect on lipid metabolism in patients with AS. However, these studies focused only on middle-aged and older populations over 50 years of age and had short intervention periods, poor quality control and patient compliance, and no stratification by age and gender to observe the effects of traditional Chinese exercise (TCE) on patients with AS. Therefore, this meta-analysis will explore the specific effects of different TCE interventions on lipid metabolism in patients with AS through subgroup analysis of factors such as age, gender, intervention cycle and training method and lay the foundation of evidence-based medicine for the promotion of TCE in both clinical practice and the community.

METHODS AND ANALYSIS

A systematic approach will be completed to search the literature published up to 30 September 2021 in the following databases: Web of Science, PubMed, Embase, Cochrane Library, EBSCO and CNKI. Other databases will also be searched manually. Lipid metabolism is the primary outcome indicator. Data synthesis, sensitivity analysis, regression analysis, subgroup analysis and risk bias evaluation will be performed using RevMan V.5.3 software. In addition, funnel plots generated by Begg's and Egger's tests will be used to assess reporting bias.

ETHICS AND DISSEMINATION

Ethical approval and consent are not necessary as no primary data will be collected. The results of the study will be disseminated through carefully reviewed publications.

PROSPERO REGISTRATION NUMBER

CRD42022304283.

Cardiac Rehabilitation Improves Endothelial Function in Coronary Artery Disease Patients

Exercise-based cardiac rehabilitation may be an effective non-pharmacological intervention for improving endothelial function in coronary artery disease patients. Therefore, this systematic review with meta-analysis aimed to (a) estimate the training-induced effect on endothelial and vascular smooth muscle function, assessed by flow-mediated dilation and nitroglycerin-mediated dilation, respectively, in coronary artery disease patients; and to (b) study the influence of potential trial-level variables (i. e. study and intervention characteristics) on the training-induced effect on endothelial and vascular smooth muscle function. Electronic searches were performed in Pubmed, Scopus, and Embase up to February 2021. Random-effects models of standardised mean change were estimated. Heterogeneity analyses were performed by using the Chi ² test and I ² index. Our results showed that exercise-based cardiac rehabilitation significantly enhanced flow-mediated dilation (1.04 [95% confidence interval=0.76 to 1.31]) but did not significantly change nitroglycerin-mediated dilation (0.05 [95% confidence interval=-0.03 to 0.13]). Heterogeneity testing reached statistical significance (p<.001) with high inconsistency for flow-mediated dilation (I ² =92%). Nevertheless, none of the analysed variables influenced the training-induced effect on flow-mediated dilation. Exercise-based cardiac rehabilitation seems to be an effective therapeutic strategy for improving endothelial-dependent dilation in coronary artery disease patients, which may aid in the prevention of cardiovascular events.

Exercise and Cardiovascular Progenitor Cells

Autologous stem/progenitor cell-based methods to restore blood flow and function to ischemic tissues are clinically appealing for the substantial proportion of the population with cardiovascular diseases. Early preclinical and case studies established the therapeutic potential of autologous cell therapies for neovascularization in ischemic tissues. However, trials over the past ∼15 years reveal the benefits of such therapies to be much smaller than originally estimated and a definitive clinical benefit is yet to be established. Recently, there has been an emphasis on improving the number and function of cells [herein generally referred to as circulating angiogenic cells (CACs)] used for autologous cell therapies. CACs include of several subsets of circulating cells, including endothelial progenitor cells, with proangiogenic potential that is largely exerted through paracrine functions. As exercise is known to improve CV outcomes such as angiogenesis and endothelial function, much attention is being given to exercise to improve the number and function of CACs. Accordingly, there is a growing body of evidence that acute, short-term, and chronic exercise have beneficial effects on the number and function of different subsets of CACs. In particular, recent studies show that aerobic exercise training can increase the number of CACs in circulation and enhance the function of isolated CACs as assessed in ex vivo assays. This review summarizes the roles of different subsets of CACs and the effects of acute and chronic exercise on CAC number and function, with a focus on the number and paracrine function of circulating CD34+ cells, CD31+ cells, and CD62E+ cells. © 2019 American Physiological Society. Compr Physiol 9:767-797, 2019.

The Relationship Between Cardiorespiratory Fitness and Arterial Stiffness in Middle-Aged Men with Abdominal Obesity

BACKGROUND

Abdominal obesity increases rapidly after middle age in Korean men, and there is an associated trend toward increasing levels of cardiovascular disease (CVD). The purpose of this study was to examine the effect of cardiorespiratory fitness (CRF) on arterial stiffness in men with abdominal obesity.

METHODS

A total of 387 middle-aged men (ages 42-59 years) with abdominal obesity participated in this cross-sectional study. Abdominal obesity was defined as a waist circumference ≥90 cm. Arterial stiffness was derived from brachial/ankle pulse wave velocity (baPWV). A treadmill exercise test was conducted to directly assess CRF using the peak oxygen uptake. Blood glucose, blood pressure, lipids, C-related protein (CRP), and baPWV were measured at rest.

RESULTS

CRF was inversely associated with baPWV (r = -0.340, P = 0.014) and CRP level (r = -0.325, P = 0.026). In addition, high CRF was associated with a lower triglyceride level (r = -0.219, P = 0.030) and a higher high-density lipoprotein cholesterol level (r = 0.317, P = 0.019).

CONCLUSIONS

These results demonstrated that high CRF was inversely associated with arterial stiffness in men with abdominal obesity. These results suggest that maintaining a high level of CRF can help middle-aged men with abdominal obesity to improve blood factors related to CVD.

Adult Stem Cells in Vascular Remodeling

Understanding the contribution of vascular cells to blood vessel remodeling is critical for the development of new therapeutic approaches to cure cardiovascular diseases (CVDs) and regenerate blood vessels. Recent findings suggest that neointimal formation and atherosclerotic lesions involve not only inflammatory cells, endothelial cells, and smooth muscle cells, but also several types of stem cells or progenitors in arterial walls and the circulation. Some of these stem cells also participate in the remodeling of vascular grafts, microvessel regeneration, and formation of fibrotic tissue around biomaterial implants. Here we review the recent findings on how adult stem cells participate in CVD development and regeneration as well as the current state of clinical trials in the field, which may lead to new approaches for cardiovascular therapies and tissue engineering.

Effects of resistance exercise on endothelial progenitor cell mobilization in women

This study aimed to determine the effect of a single bout of resistance exercise at different intensities on the mobilization of circulating EPCs over 24 hours in women. In addition, the angiogenic factors stromal cell-derived factor 1 (SDF-1α), vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1-alpha (HIF-1α) and erythropoietin (EPO) were measured as potential mechanisms for exercise-induced EPCs mobilization. Thirty-eight women performed a resistance exercise session at an intensity of 60% (n = 13), 70% (n = 12) or 80% (n = 13) of one repetition maximum. Each session was comprised of three sets of 12 repetitions of four exercises: bench press, dumbbell curl, dumbbell squat, and standing dumbbell upright row. Blood was sampled at baseline and immediately, 6 hours, and 24 hours post-exercise. Circulating EPC and levels of VEGF, HIF-1α and EPO were significantly higher after exercise (P < 0.05). The change in EPCs from baseline was greatest in the 80% group (P < 0.05), reaching the highest at 6 hours post-exercise. The change in EPCs from baseline to 6 hours post-exercise was correlated with the change in VEGF (r = 0.492, P = 0.002) and HIF-1α (r = 0.388, P = 0.016). In general, a dose-response relationship was observed, with the highest exercise intensities promoting the highest increases in EPCs and angiogenic factors.

Leisure-time physical activity across adulthood and biomarkers of cardiovascular disease at age 60-64: A prospective cohort study

Background and aims

This study examined associations between leisure-time physical activity (LTPA) across adulthood (from age 36) and cardiovascular disease (CVD) biomarkers at age 60–64.

Methods

LTPA was reported by study participants from the MRC National Survey of Health and Development at ages 36, 43, 53 and 60–64 (n = 1754) and categorised as inactive, moderately active (1–4/month) or most active (5+/month) at each age. Linear regression was used to examine associations between a cumulative adulthood LTPA score (range = 0–8), and change in LTPA between ages 36 and 60–64 (i.e. always inactive, became inactive, became active, always active) and inflammatory [C-reactive protein (CRP), interleukin-6 (IL-6)], endothelial [tissue-Plasminogen Activator (t-PA), E-selectin] and adipokine [leptin, adiponectin] measures extracted from overnight fasting blood samples at age 60–64.

Results

The more active a participant was over adulthood, the better their biomarker profile, e.g. fully-adjusted difference in t-PA (both sexes) and adiponectin (women) per unit increase in the LTPA score (95% confidence interval) = −2.2% (−3.6; −0.8) and 2.0% (0.2; 3.8). Those that became active at age 60–64 showed slightly healthier biomarker profiles than those that became inactive [e.g. fully-adjusted difference in IL-6 = −9.9% (−23.9; 4.1) vs. −3.8% (−12.4; 4.8)], although the best profiles were seen for those always active [IL-6: −15.0% (−24.2; −5.7)], when compared with the always inactive group.

Conclusions

Greater accumulation of LTPA across adulthood was associated with a more favourable CVD biomarker profile in early old age. Earlier uptake and long-term maintenance of LTPA may provide the greatest benefits for CVD prevention.

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Greater LTPA over 28 years related to healthier atherosclerotic biomarker profiles.

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Taking up LTPA related to better biomarker levels than staying inactive over life.

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Differences in biomarker levels by LTPA were only partly mediated by body size.

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Earlier uptake and long-term maintenance of LTPA may provide greatest benefits.

Epigenetic effects of physical activity in elderly patients with cardiovascular disease

Cardiovascular disease (CVD) is an important public health problem affecting especially the elderly. Over the past 20years, an increasing number of studies have examined its underlying pathophysiological mechanisms and new therapies are continually being discovered. However, despite considerable progress in CVD management, mortality and morbidity remain a major healthcare concern, and frequent hospital admissions compromise the daily life and social activities of these patients. Physical activity has emerged as an important non-pharmacological adjunctive therapy for CVD in older patients, especially for heart failure patients, exerting its beneficial effects on mortality, morbidity, and functional capacity. The mechanisms underlying the cardiovascular benefits of exercise are not wholly clear. Mounting evidence suggest that epigenetic modifications, such as DNA methylation, histone post-translational modifications (hPTMs) and non-coding RNA, especially microRNAs (miRNAs), may be induced by physical activity. Recently, a number of miRNAs have been identified as key players in gene expression modulation by exercise. MiRNAs are synthesized by living cells and actively released into the bloodstream through different shuttles. The epigenetic information, thus carried and delivered, is involved in the interplay between environmental factors, including physical activity, and individual genetic make-up. We review and discuss the effects of exercise on age-related CVDs, focusing on circulating miRNA (c-miRNAs) modulation. Epigenetic mechanisms may have clinical relevance in CVD prevention and management; since they can be modified, insights into the implications of lifestyle-related epigenetic changes in CVD etiology may help develop therapeutic protocols of exercise training that can be suitable and effective for elderly patients.

Modulation of Local and Systemic Heterocellular Communication by Mechanical Forces: A Role of Endothelial Nitric Oxide Synthase

In this review, we discuss the role of nitric oxide (NO) as a key physiological mechanotransducer modulating both local and systemic heterocellular communication and contributing to the integrated (patho)physiology of the cardiovascular system. A deeper understanding of mechanotransduction-mediated local and systemic nodes controlling heterocellular communication between the endothelium, blood cells, and other cell types (e.g., cardiomyocytes) may suggest novel therapeutic strategies for endothelial dysfunction and cardiovascular disease. Recent Advances: Mechanical forces acting on mechanoreceptors on endothelial cells activate the endothelial NO synthase (eNOS) to produce NO. NO participates in (i) abluminal heterocellular communication, inducing vasorelaxation, and thereby regulating vascular tone and blood pressure; (ii) luminal heterocellular communication, inhibiting platelet aggregation, and controlling hemostasis; and (iii) systemic heterocellular communication, contributing to adaptive physiological processes in response to exercise and remote ischemic preconditioning. Interestingly, shear-induced eNOS-dependent activation of vascular heterocellular communication constitutes the molecular basis of all methods applied in the clinical routine for evaluation of endothelial function. Critical Issues and Future Directions: The integrated physiology of heterocellular communication is still not fully understood. Dedicated experimental models are needed to analyze messengers and mechanisms underpinning heterocellular communication in response to physical forces in the cardiovascular system (and elsewhere). Antioxid. Redox Signal. 26, 917-935.

Physical activity in primary and secondary prevention of cardiovascular disease: Overview updated

Although the observed progress in the cardiovascular disease treatment, the incidence of new and recurrent coronary artery disease remains elevated and constitutes the leading cause of death in the developed countries. Three-quarters of deaths due to cardiovascular diseases could be prevented with adequate changes in lifestyle, including increased daily physical activity. New evidence confirms that there is an inverse dose-response relationship between physical activity and cardiovascular disease and mortality risk. However, participation in moderate to vigorous physical activity may not fully attenuate the independent effect of sedentary activities on increased risk for cardiovascular diseases. Physical activity also plays an important role in secondary prevention of cardiovascular diseases by reducing the impact of the disease, slowing its progress and preventing recurrence. Nonetheless, most of eligible cardiovascular patients still do not benefit from secondary prevention/cardiac rehabilitation programs. The present review draws attention to the importance of physical activity in the primary and secondary prevention of cardiovascular diseases. It also addresses the mechanisms by which physical activity and regular exercise can improve cardiovascular health and reduce the burden of the disease.

High-intensity Interval training enhances mobilization/functionality of endothelial progenitor cells and depressed shedding of vascular endothelial cells undergoing hypoxia

PURPOSE

Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte-derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate-intensity continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition.

METHODS

Sixty healthy sedentary males were randomized to engage in either HIT (3-min intervals at 40 and 80 % VO_2max for five repetitions, n = 20) or MCT (sustained 60 % VO_2max, n = 20) for 30 min/day, 5 days/week for 6 weeks, or to a control group (CTL) that did not received exercise intervention (n = 20). Mon-EPC characteristics and EPC functionality under hypoxic exercise (HE, 100 W under 12 % O₂) were determined before and after HIT, MCT, and CTL.

RESULTS

The results demonstrated that after the intervention, the HIT group exhibited larger improvements in VO_2peak, estimated peak cardiac output (Q_C), and estimated peak perfusions of frontal cerebral lobe (Q_FC) and vastus lateralis (Q_VL) than the MCT group. Furthermore, HIT (a) increased circulating CD14⁺⁺/CD16^-/CD34⁺/KDR⁺ (Mon-1 EPC) and CD14⁺⁺/CD16⁺/CD34⁺/KDR⁺ (Mon-2 EPC) cell counts, (b) promoted the migration and tube formation of EPCs, (c) diminished the shedding of endothelial (CD34^-/KDR⁺/phosphatidylserine⁺) cells, and (d) elevated plasma nitrite plus nitrate, stromal cell-derived factor-1, matrix metalloproteinase-9, and vascular endothelial growth factor-A concentrations at rest or following HE, compared to those of MCT. In addition, Mon-1 and -2 EPC counts were directly related to VO_2peak and estimated peak Q_C, Q_FC, and Q_VL.

CONCLUSIONS

HIT is superior to MCT for improving hemodynamic adaptation and Mon-EPC production. Moreover, HIT effectively enhances EPC functionality and suppresses endothelial injury undergoing hypoxia.

Statins, HMG-CoA Reductase Inhibitors, Improve Neovascularization by Increasing the Expression Density of CXCR4 in Endothelial Progenitor Cells

Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, are used to reduce cholesterol biosynthesis in the liver. Accordingly, statins regulate nitric oxide (NO) and glutamate metabolism, inflammation, angiogenesis, immunity and endothelial progenitor cells (EPCs) functions. The function of EPCs are regulated by stromal cell-derived factor 1 (SDF-1), vascular endothelial growth factor (VEGF), and transforming growth factor β (TGF-β), etc. Even though the pharmacologic mechanisms by which statins affect the neovasculogenesis of circulating EPCs, it is still unknown whether statins affect the EPCs function through the regulation of CXCR4, a SDF-1 receptor expression. Therefore, we desired to explore the effects of statins on CXCR4 expression in EPC-mediated neovascularization by in vitro and in vivo analyses. In animal studies, we analyzed the effects of atorvastatin or rosuvastatin treatments in recovery of capillary density and blood flow, the expression of vWF and CXCR4 at ischemia sites in hindlimb ischemia ICR mice. Additionally, we analyzed whether the atorvastatin or rosuvastatin treatments increased the mobilization, homing, and CXCR4 expression of EPCs in hindlimb ischemia ICR mice that underwent bone marrow transplantation. The results indicated that statins treatment led to significantly more CXCR4-positive endothelial progenitor cells incorporated into ischemic sites and in the blood compared with control mice. In vivo, we isolated human EPCs and analyzed the effect of statins treatment on the vasculogenic ability of EPCs and the expression of CXCR4. Compared with the control groups, the neovascularization ability of EPCs was significantly improved in the atorvastatin or rosuvastatin group; this improvement was dependent on CXCR4 up-regulation. The efficacy of statins on improving EPC neovascularization was related to the SDF-1α/CXCR4 axis and might be regulated by the NO. In conclusion, atorvastatin and rosuvastatin improved neovascularization in hindlimb ischemia mice; this effect may have been mediated by increased CXCR4 expression in EPCs.

Circulating endothelial cells in children: role of fitness, activity, and adiposity

PURPOSE

Circulating endothelial cells (CEC) are thought to be useful biomarkers of endothelial dysfunction and overall cardiovascular health. The extent to which CEC are influenced by fitness, physical activity, and adiposity in youth remains unknown, as they have seldom been examined in the pediatric population. This study assessed resting levels of CEC in boys and girls of different chronological and biological age and explored the relationship between these cells and aerobic fitness, physical activity, and adiposity.

METHODS

Seventy-five children (39 males; median [interquartile range], age = 14.4 [5.8]) completed two study visits. During the first visit, basic anthropometric data were collected and biological age was calculated. Peak mechanical power (Wpeak) was determined using the McMaster All-Out Continuous cycling test. Participants then wore an accelerometer over a 7-d period to assess habitual levels of moderate-to-vigorous physical activity. During visit 2, percent body fat (%BF) was assessed by dual-energy x-ray absorptiometry. A fasted blood sample was also collected from which concentrations of CEC, identified as CD31CD34CD45CD133, were quantified by flow cytometry.

RESULTS

No differences were seen in CEC by sex, chronological age, or biological age. The median (interquartile range) CEC concentration was 32.3 × 10 (63.0 × 10), representing 1.3% (2.7%) of collected peripheral blood mononuclear cells. CEC concentration was associated with Wpeak normalized to lean body mass (r = 0.36, P < 0.01) and time spent in moderate-to-vigorous physical activity (r = -0.27, P = 0.02). No relationship was observed between CEC and %BF.

CONCLUSION

Healthy children demonstrate relatively low concentrations of CECs. Because CEC represent a population of mature endothelial cells shed from the intima after irreversible damage, they may be more reflective of recent physical activity levels rather than fitness or level of adiposity.

Effects of acute exercise on markers of inflammation in pediatric chronic kidney disease: a pilot study

BACKGROUND

Children and adolescents with chronic kidney disease (CKD) are chronically exposed to high levels of inflammation, placing them at an increased risk of secondary health complications. Regular exercise may represent an effective therapy to reduce inflammation. The aims of this pilot study were to determine the effects of acute exercise on inflammation and immune cell counts in CKD.

METHODS

Nine children and adolescents (4 males) with CKD stages III-V performed a graded exercise test to determine peak oxygen uptake (VO2peak). Following a 10-min break, participants cycled for 20 min at 50 % of VO2peak. Blood samples were collected before and after the exercise period for the determination of complete blood counts, natural killer cells (NK(bright), NK(dim)) and circulating progenitor cell (CPC) counts, as well as interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) concentrations.

RESULTS

Complete blood counts and NK(dim) cell and CPC counts were unchanged with exercise. Following exercise, NK(bright) cell counts increased (7.4 ± 4.3 vs. 12.2 ± 8.3 × 10(6) cells/L; p = 0.02), while trends were observed for an increase in IL-6 (2.1 ± 2.2 vs. 2.7 ± 2.6 pg/mL; p = 0.08), decrease in TNF-α (4.5 ± 1.2 vs. 4.2 ± 1.0 pg/mL; p = 0.08) and an increase in the IL-6:TNF-α ratio (0.6 ± 0.7 vs. 0.8 ± 0.8; p = 0.07).

CONCLUSIONS

Our findings suggest that acute exercise may create an anti-inflammatory environment in children and adolescents with CKD stages III-V.

The number of circulating endothelial progenitor cells in healthy individuals--effect of some anthropometric and environmental factors (a pilot study)

PURPOSE

The aim of the study was the evaluation of the number of circulating endothelial progenitor cells (CEPCs) in healthy people and the assessment of the variability of quantitative of CEPCs after 6 weeks.

MATERIAL AND METHODS

The study involved 48 healthy individuals; the group consisted of 24 men and 24 women; the mean age of 34. The criterion for the patients' eligibility for the study was the absence of diabetes, thrombosis and cardiovascular diseases such as atherosclerosis, hypertension, and heart failure. Neither did the respondents take any medication that could clearly affect the value of the results. In the whole blood samples the number of circulating endothelial progenitor cells was determined using flow cytometry. During the analysis the fluorescence of 100,000 cells was measured. CEPCs were identified with immunophenotype CD45-, CD31+, CD34+, CD133+.

RESULTS

In the study, the median of the number of circulating endothelial progenitor cells in the whole group was 0.41/μL. There was also recorded an increased number of CEPCs after 6 weeks, as compared to the baseline; the difference was significant. There were no differences in the number of CEPCs between the women and the men. There was found no effect on the number of CEPCs factors such as: smoking, physical activity and alcohol consumption.

CONCLUSIONS

The study showed that in healthy individuals the gender had no essential effect on the number of endothelial progenitor cells. Based on the demographic and lifestyle data acquired, it is difficult to explain the increase number of CEPCs after 6 weeks.

Benefits of exercise training on coronary blood flow in coronary artery disease patients

Every 34 seconds an American experiences a myocardial infarction or cardiac death. Approximately 80% of these coronary artery disease (CAD)-related deaths are attributable to modifiable behaviors, such as a lack of physical exercise training (ET). Regular ET decreases CAD morbidity and mortality through systemic and cardiac-specific adaptations. ET increases myocardial oxygen demand acting as a stimulus to increase coronary blood flow and thus myocardial oxygen supply, which reduces myocardial infarction and angina. ET augments coronary blood flow through direct actions on the vasculature that improve endothelial and coronary smooth muscle function, enhancing coronary vasodilation. Additionally, ET promotes collateralization, thereby, increasing blood flow to ischemic myocardium and also treats macrovascular CAD by attenuating the progression of coronary atherosclerosis and restenosis, potentially through stabilization of atherosclerotic lesions. In summary, ET can be used as a relatively safe and inexpensive way to prevent and treat CAD.

Regular exercise training increases the number of endothelial progenitor cells and decreases homocysteine levels in healthy peripheral blood

Endothelial progenitor cells (EPCs) are known to play an important role in the repair of damaged blood vessels. We used an endothelial progenitor cell colony-forming assay (EPC-CFA) to determine whether EPC numbers could be increased in healthy individuals through regular exercise training. The number of functional EPCs obtained from human peripheral blood-derived AC133 stem cells was measured after a 28-day regular exercise training program. The number of total endothelial progenitor cell colony-forming units (EPC-CFU) was significantly increased compared to that in the control group (p=0.02, n=5). In addition, we observed a significant decrease in homocysteine levels followed by an increase in the number of EPC-CFUs (p=0.04, n=5), indicating that the 28-day regular exercise training could increase the number of EPC colonies and decrease homocysteine levels. Moreover, an inverse correlation was observed between small-endothelial progenitor cell colony-forming units (small-EPC-CFUs) and plasma homocysteine levels in healthy men (r=-0.8125, p=0.047). We found that regular exercise training could increase the number of EPC-CFUs and decrease homocysteine levels, thus decreasing the cardiovascular disease risk in men.

Hypoxic exercise training improves cardiac/muscular hemodynamics and is associated with modulated circulating progenitor cells in sedentary men

BACKGROUND

Circulating progenitor cells (CPCs) improve cardiovascular function and organ perfusion by enhancing the capacities of endothelial repair and neovasculogenesis. This study investigates whether exercise regimens with/without hypoxia affect cardiac and muscular hemodynamics by modulating CPCs and angiogenic factors.

METHODS

Forty sedentary males were randomly divided into hypoxic (HT, n=20) and normoxic (NT, n=20) training groups. The subjects were trained on a bicycle ergometer at 60%VO(2max) under 15% (HT) or 21% (NT) O2 conditions for 30 min daily, five days weekly for five weeks.

RESULTS

After the five-week interventions, the HT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the HT regimen (i) enhanced cardiac output (Q(H)) and perfusion (Q(M))/oxygenation of vastus lateralis during exercise; (ii) increased levels of CD34(+)/KDR(+)/CD117(+), CD34(+)/KDR(+)/CD133(+), and CD34(+)/KDR(+)/CD31(+) cells in blood; (iii) promoted the proliferative capacity of these CPC subsets, and (iv) elevated plasma nitrite/nitrate, stromal cell-derived factor-1 (SDF-1), matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor-A (VEGF-A) concentrations. Despite the lack of changes in Q(H) and the number or proliferative capacity of CD34(+)/KDR(+)/CD117(+) or CD34(+)/KDR(+)/CD31(+) cells, the NT regimen elevated both Q(M) and plasma nitrite/nitrate levels and suppressed the shedding of endothelial cells (CD34(-)/KDR(+)/phosphatidylserine(+) cells).

CONCLUSIONS

The HT regimen improves cardiac and muscular hemodynamic adaptations, possibly by promoting the mobilization/function of CPCs and the production of angiogenic factors.

Correlations of non-exercise activity thermogenesis to metabolic parameters in Japanese patients with type 2 diabetes

BACKGROUND

Non-exercise activity thermogenesis (NEAT) is the energy expenditure due to physical activities besides active sports-like exercise and resistance training in daily life.

METHODS

We studied 45 subjects (22 women and 23 men) with type 2 diabetes who did not take any hypoglycemic, anti-hypertensive, or cholesterol-lowering agents and asked them about physical activity concerned with NEAT using an original questionnaire modified from a compendium of physical activities. We studied the association of the NEAT score to body weight, waist circumference, blood pressure, glucose and lipid metabolism, and arterial stiffness.

RESULTS

The NEAT score was negatively correlated with serum insulin levels (r = -0.42, P < 0.05) in all subjects. The NEAT score was also negatively correlated with waist circumference (r = -0.509, P < 0.05) and positively correlated with high-density lipoprotein-cholesterol levels (r = 0.494, P < 0.05) in women, and negatively associated with serum insulin levels (r = -0.732, p < 0.005), systolic (r = -0.482, P < 0.05) and diastolic blood pressure (r = -0.538, P < 0.05) in patients with abdominal obesity. Furthermore, the NEAT score was negatively associated with pulse wave velocity (r = -0.719, P < 0.005) in smokers.

CONCLUSION

The study demonstrated that NEAT is associated with amelioration in insulin sensitivity, waist circumference, high-density lipoprotein-cholesterol, blood pressure and the marker for atherosclerosis in patients with type 2 diabetes.

Role of exercise in the prevention of cardiovascular disease: results, mechanisms, and new perspectives

On an empirical basis, exercise has been regarded as a fundamental pre-requisite for human well-being and physical integrity since classical times. Only in the last decades, however, scientific evidence has accumulated proving its role in the prevention and treatment of multiple chronic diseases beyond any reasonable doubt. Few treatment strategies in medicine have been tested so rigorously in large cohorts of patients as regular physical exercise. With the advent of molecular biology, the underlying mechanisms, such as NO bioavailability and mobilization of progenitor cells, could be identified. This enhances our understanding of this therapeutic tool. Unfortunately, the low compliance rate of the patients is the major drawback of the intervention exercise training (ET). The objective of this manuscript is to summarize the current knowledge with respect to ET on cardiovascular disease (CVD) and the molecular changes elicited by ET. Finally, we will critically assess reasons why ET as therapeutic option is not as effective at the population level in preventing CVD and what we may change in the future to make ET the most effective intervention to fight the development of CVD.

A randomized trial of exercise for blood pressure reduction in type 2 diabetes: effect on flow-mediated dilation and circulating biomarkers of endothelial function

OBJECTIVE

To investigate the effect of an exercise intervention on flow-mediated dilation (FMD) and circulating endothelial biomarkers in adults with type 2 diabetes (T2DM).

METHODS

Sedentary adults (n = 140), aged 40-65, with T2DM and untreated pre or Stage I hypertension or treated hypertension were randomized to a 6-month, supervised, exercise program (3× week) or a sedentary control. Assessments included BMI, body and visceral fat, blood pressure, lipids, HbA1c, insulin sensitivity (QUICKI), fitness, FMD, E-selectin, P-selectin, intracellular and vascular cellular adhesion molecules (ICAM, VCAM), and tissue plasminogen activator (tPA). Intervention effects were compared by t-tests. Pearson's correlations were calculated between changes in cardiovascular risk factors and endothelial outcomes.

RESULTS

Exercisers significantly improved BMI (-0.6 kg/m(2)), body fat % (-1.4%), HbA1c (-0.5%), and fitness (2.9 mL/kg min) vs. controls (p < 0.05). However, there were no differences between groups in changes in FMD, E-selectin, P-selectin, ICAM, VCAM, or tPA. Among exercisers, changes in cardiovascular risk factors correlated with several biomarkers. Decreased P-selectin correlated with decreased BMI (r = 0.29, p = 0.04) and increased HDL cholesterol (r = -0.36, p = 0.01). Decreased ICAM correlated with decreased triglycerides and HbA1c (r = 0.30, p = 0.04; r = 0.31, p = 0.03) and increased QUICKI (r = - 0.28, p = 0.05). Decreased tPA correlated with decreased total body and visceral fat (r = 0.28, p = 0.05; r = 0.38, p = 0.008) and increased QUICKI (r = -0.38, p = 0.007).

CONCLUSIONS

While exercise resulted in improved fitness, body composition, and glycemic control, there were no changes in FMD or circulating endothelial biomarkers. The associations of changes in cardiovascular risk factors and endothelial biomarkers suggest that improvement in risk factors could mediate the exercise-induced improvements in endothelial function seen in prior studies.

Heartache and heartbreak--the link between depression and cardiovascular disease

The close, bidirectional relationship between depression and cardiovascular disease is well established. Major depression is associated with an increased risk of coronary artery disease and acute cardiovascular sequelae, such as myocardial infarction, congestive heart failure, and isolated systolic hypertension. Morbidity and mortality in patients with cardiovascular disease and depression are significantly higher than in patients with cardiovascular disease who are not depressed. Various pathophysiological mechanisms might underlie the risk of cardiovascular disease in patients with depression: increased inflammation; increased susceptibility to blood clotting (owing to alterations in multiple steps of the clotting cascade, including platelet activation and aggregation); oxidative stress; subclinical hypothyroidism; hyperactivity of the sympatho-adrenomedullary system and the hypothalamic-pituitary-adrenal axis; reductions in numbers of circulating endothelial progenitor cells and associated arterial repair processes; decreased heart rate variability; and the presence of genetic factors. Early identification of patients with depression who are at risk of cardiovascular disease, as well as prevention and appropriate treatment of cardiovascular disease in these patients, is an important and attainable goal. However, adequately powered studies are required to determine the optimal treatment regimen for patients with both depression and cardiovascular disorders.

Endothelial progenitor cells: a new player in lupus?

Patients with systemic lupus erythematosus (SLE) have a greatly increased risk of cardiovascular disease. There is growing interest in the link between vascular damage and lupus-specific inflammatory factors. Impaired endothelial repair could account for the endothelial dysfunction in this patient group. This review describes the contribution that endothelial progenitor cells could play in the pathogenesis of premature vascular damage in this disease. The methods of isolation, detection, and characterization of endothelial progenitor cells, together with their potential role in repair of the endothelium and as a therapeutic target in SLE, are discussed.

Effects of exercise training on coronary collateralization and control of collateral resistance

Coronary collateral vessels serve as a natural protective mechanism to provide coronary flow to ischemic myocardium secondary to critical coronary artery stenosis. The innate collateral circulation of the normal human heart is typically minimal and considerable variability occurs in extent of collateralization in coronary artery disease patients. A well-developed collateral circulation has been documented to exert protective effects upon myocardial perfusion, contractile function, infarct size, and electrocardiographic abnormalities. Thus therapeutic augmentation of collateral vessel development and/or functional adaptations in collateral and collateral-dependent arteries to reduce resistance into the ischemic myocardium represent a desirable goal in the management of coronary artery disease. Tremendous evidence has provided documentation for the therapeutic benefits of exercise training programs in patients with coronary artery disease (and collateralization); mechanisms that underlie these benefits are numerous and multifaceted, and currently under investigation in multiple laboratories worldwide. The role of enhanced collateralization as a major beneficial contributor has not been fully resolved. This topical review highlights literature that examines the effects of exercise training on collateralization in the diseased heart, as well as effects of exercise training on vascular endothelial and smooth muscle control of regional coronary tone in the collateralized heart. Future directions for research in this area involve further delineation of cellular/molecular mechanisms involved in effects of exercise training on collateralized myocardium, as well as development of novel therapies based on emerging concepts regarding exercise training and coronary artery disease.

Effects of exercise on endothelium and endothelium/smooth muscle cross talk: role of exercise-induced hemodynamics

Physical activity, exercise training, and fitness are associated with decreased cardiovascular risk. In the context that a risk factor "gap" exists in the explanation for the beneficial effects of exercise on cardiovascular disease, it has recently been proposed that exercise generates hemodynamic stimuli which exert direct effects on the vasculature that are antiatherogenic. In this review we briefly introduce some of the in vitro and in vivo evidence relating exercise hemodynamic modulation and vascular adaptation. In vitro data clearly demonstrate the importance of shear stress as a potential mechanism underlying vascular adaptations associated with exercise. Supporting this is in vivo human data demonstrating that exercise-mediated shear stress induces localized impacts on arterial function and diameter. Emerging evidence suggests that exercise-related changes in hemodynamic stimuli other than shear stress may also be associated with arterial remodeling. Taken together, in vitro and in vivo data strongly imply that hemodynamic influences combine to orchestrate a response to exercise and training that regulates wall stress and peripheral vascular resistance and contributes to the antiatherogenic impacts of physical activity, fitness, and training.