Endothelial Progenitor Cell Number and Colony-forming Capacity in Overweight and Obese Adults

OBJECTIVE: To investigate whether adiposity influences endothelial progenitor cell (EPC) number and colony-forming capacity.DESIGN: Cross-sectional study of normal weight, overweight and obese adult humans.PARTICIPANTS: Sixty-seven sedentary adults (aged 45-65 years): 25 normal weight (body mass index (BMI) or=30 kg/m(2); 18 males/6 females). All participants were non-smokers and free of overt cardiometabolic disease.MEASUREMENTS: Peripheral blood samples were collected and circulating EPC number was assessed by flow cytometry. Putative EPCs were defined as CD45(-)/CD34(+)/VEGFR-2(+)/CD133(+) or CD45(-)/CD34(+) cells. EPC colony-forming capacity was measured in vitro using a colony-forming unit (CFU) assay.RESULTS: Number of circulating putative EPCs (either CD45(-)/CD34(+)/VEGFR-2(+)/CD133(+) or CD45(-)/CD34(+) cells) was lower (P\u3c0.05) in obese (0.0007±0.0001%; 0.050±0.006%) compared with overweight (0.0016±0.0004%; 0.089±0.019%) and normal weight (0.0015±0.0003%; 0.082±0.008%) adults. There were no differences in EPC number between the overweight and normal weight groups. EPC colony-formation was significantly less in the obese (6±1) and overweight (4±1) compared with normal weight (9±2) adults.CONCLUSION: These results indicate that: (1) the number of circulating EPCs is lower in obese compared with overweight and normal weight adults; and (2) EPC colony-forming capacity is blunted in overweight and obese adults compared with normal weight adults. Impairments in EPC number and function may contribute to adiposity-related cardiovascular risk

Role of Histone Acetylation in the Stimulatory Effect of Valproic Acid on Vascular Endothelial Tissue-Type Plasminogen Activator Expression

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Interleukin-1 Receptor-Associated Kinase-3 Is a Key Inhibitor of Inflammation in Obesity and Metabolic Syndrome

BACKGROUND: Visceral obesity is associated with the rising incidence of type 2 diabetes and metabolic syndrome. Low-grade chronic inflammation and oxidative stress synergize in obesity and obesity-induced disorders. OBJECTIVE: We searched a cluster of molecules that support interactions between these stress conditions in monocytes. METHODS: RNA expressions in blood monocytes of two independent cohorts comprising 21 and 102 obese persons and 46 age-matched controls were determined by microarray and independently validated by quantitative RT-PCR analysis. The effect of three-month weight loss after bariatric surgery was determined. The effect of RNA silencing on inflammation and oxidative stress was studied in human monocytic THP-1 cells. RESULTS: Interleukin-1 receptor-associated kinase-3 (IRAK3), key inhibitor of IRAK/NFκB-mediated chronic inflammation, is downregulated in monocytes of obese persons. Low IRAK3 was associated with high superoxide dismutase-2 (SOD2), a marker of mitochondrial oxidative stress. A comparable expression profile was also detected in visceral adipose tissue of the same obese subjects. Low IRAK3 and high SOD2 was associated with a high prevalence of metabolic syndrome (odds ratio: 9.3; sensitivity: 91%; specificity: 77%). By comparison, the odds ratio of high-sensitivity C-reactive protein, a widely used marker of systemic inflammation, was 4.3 (sensitivity: 69%; specificity: 66%). Weight loss was associated with an increase in IRAK3 and a decrease in SOD2, in association with a lowering of systemic inflammation and a decreasing number of metabolic syndrome components. We identified the increase in reactive oxygen species in combination with obesity-associated low adiponectin and high glucose and interleukin-6 as cause of the decrease in IRAK3 in THP-1 cells in vitro. CONCLUSION: IRAK3 is a key inhibitor of inflammation in association with obesity and metabolic syndrome. Our data warrant further evaluation of IRAK3 as a diagnostic and prognostic marker, and as a target for intervention

Perivascular Fat and the Microcirculation: Relevance to Insulin Resistance, Diabetes, and Cardiovascular Disease

Type 2 diabetes and its major risk factor, obesity, are a growing burden for public health. The mechanisms that connect obesity and its related disorders, such as insulin resistance, type 2 diabetes, and hypertension, are still undefined. Microvascular dysfunction may be a pathophysiologic link between insulin resistance and hypertension in obesity. Many studies have shown that adipose tissue-derived substances (adipokines) interact with (micro)vascular function and influence insulin sensitivity. In the past, research focused on adipokines from perivascular adipose tissue (PVAT). In this review, we focus on the interactions between adipokines, predominantly from PVAT, and microvascular function in relation to the development of insulin resistance, diabetes, and cardiovascular disease

Impact of inactivity and exercise on the vasculature in humans

The effects of inactivity and exercise training on established and novel cardiovascular risk factors are relatively modest and do not account for the impact of inactivity and exercise on vascular risk. We examine evidence that inactivity and exercise have direct effects on both vasculature function and structure in humans. Physical deconditioning is associated with enhanced vasoconstrictor tone and has profound and rapid effects on arterial remodelling in both large and smaller arteries. Evidence for an effect of deconditioning on vasodilator function is less consistent. Studies of the impact of exercise training suggest that both functional and structural remodelling adaptations occur and that the magnitude and time-course of these changes depends upon training duration and intensity and the vessel beds involved. Inactivity and exercise have direct “vascular deconditioning and conditioning” effects which likely modify cardiovascular risk

The prevalence of adverse cardiometabolic responses to exercise training with evidence-based practice is low

Lance C Dalleck,1 Gary P Van Guilder,2 Tara B Richardson,1 Chantal A Vella3 1Recreation, Exercise, and Sport Science Department, Western State Colorado University, Gunnison, CO, USA; 2Department of Health and Nutritional Sciences, South Dakota State University, Brookings, SD, USA; 3Department of Movement Sciences, WWAMI Medical Education Program, University of Idaho, Moscow, ID, USA Background: The purpose of this study was to determine the prevalence of individuals who experienced exercise-induced adverse cardiometabolic response (ACR), following an evidence-based, individualized, community exercise program. Methods: Prevalence of ACR was retrospectively analyzed in 332 adults (190 women, 142 men) before and after a 14-week supervised community exercise program. ACR included an exercise training-induced increase in systolic blood pressure of 10 mmHg, increase in plasma triglycerides (TG) of >37.0 mg/dL (0.42 mmol/L), or decrease in high-density lipoprotein cholesterol (HDL-C) of >4.0 mg/dL (0.12 mmol/L). A second category of ACR was also defined – this was ACR that resulted in a metabolic syndrome component (ACR-risk) as a consequence of the adverse response. Results: According to the above criteria, prevalence of ACR between baseline and post-program was systolic blood pressure (6.0%), TG (3.6%), and HDL-C (5.1%). The prevalence of ACR-risk was elevated TG (3.2%), impaired fasting blood glucose (2.7%), low HDL-C (2.2%), elevated waist circumference (1.3%), and elevated blood pressure (0.6%). Conclusion: Evidence-based practice exercise programming may attenuate the prevalence of exercise training-induced ACR. Our findings provide important preliminary evidence needed for the vision of exercise prescription as a personalized form of preventative medicine to become a reality. Keywords: evidence-based research, cardiovascular health, community-based research, metabolic healt

A community-based exercise intervention transitions metabolically abnormal obese adults to a metabolically healthy obese phenotype

Lance C Dalleck,1,3 Gary P Van Guilder,2,3 Tara B Richardson,1 Donald L Bredle,3 Jeffrey M Janot31Recreation, Exercise, and Sport Science Department, Western State Colorado University, Gunnison, CO, USA; 2Department of Health and Nutritional Sciences, South Dakota State University, Brookings, SD, USA; 3Department of Kinesiology, University of Wisconsin-Eau Claire, Eau Claire, WI, USABackground: Lower habitual physical activity and poor cardiorespiratory fitness are common features of the metabolically abnormal obese (MAO) phenotype that contribute to increased cardiovascular disease risk. The aims of the present study were to determine 1) whether community-based exercise training transitions MAO adults to metabolically healthy, and 2) whether the odds of transition to metabolically healthy were larger for obese individuals who performed higher volumes of exercise and/or experienced greater increases in fitness.Methods and results: Metabolic syndrome components were measured in 332 adults (190 women, 142 men) before and after a supervised 14-week community-based exercise program designed to reduce cardiometabolic risk factors. Obese (body mass index ≥30 kg · m2) adults with two to four metabolic syndrome components were classified as MAO, whereas those with no or one component were classified as metabolically healthy but obese (MHO). After community exercise, 27/68 (40%) MAO individuals (P<0.05) transitioned to metabolically healthy, increasing the total number of MHO persons by 73% (from 37 to 64). Compared with the lowest quartiles of relative energy expenditure and change in fitness, participants in the highest quartiles were 11.6 (95% confidence interval: 2.1–65.4; P<0.05) and 7.5 (95% confidence interval: 1.5–37.5; P<0.05) times more likely to transition from MAO to MHO, respectively.Conclusion: Community-based exercise transitions MAO adults to metabolically healthy. MAO adults who engaged in higher volumes of exercise and experienced the greatest increase in fitness were significantly more likely to become metabolically healthy. Community exercise may be an effective model for primary prevention of cardiovascular disease.Keywords: exercise, obesity, prevention, risk factor

INFLUENCE OF ISCHEMIC PRECONDITIONING ON RUNNING ECONOMY

M. A. Brace, G. Kaur, C. Evans, T. Trachte, S. Seidel, & G. P. Van Guilder South Dakota State University, Brookings, SD Purpose: Ischemic preconditioning (IPC) of the skeletal muscle - induced by brief episodes of sublethal ischemia followed by reperfusion – improves exercise performance, particularly maximum oxygen uptake, lactate metabolism, and time trial performance. However, to date it is not clear if the performance benefits of IPC also affect exercise economy. The purpose of this study was to test the hypothesis that leg IPC improves running economy. Methods: Currently ongoing, a randomized single-blind crossover study was employed in which 5 young healthy adult men and women (age: 25±1 yr; BMI: 21.5±3 kg/m2) completed two, 3x5 min submaximal treadmill running protocols (ranging from 107–188 meters/min) to assess running economy (Parvo Medics, TrueOne 2400) in the absence and presence of IPC. The independent variable was conditioning group (IPC versus a sham control). IPC was induced using bilateral high pressure cuffs placed on the upper thighs and inflated to 220 mmHg (EC20 rapid cuff inflator, DE Hokanson, Inc.) for 5 min, followed by 5 min of reperfusion. The sham control was identical to the IPC trial except the pressure cuffs were inflated to 20 mmHg to avoid preconditioning. The trials were separated by at least one week. Statistical Analysis: A two-tailed paired t-test was used to assess differences in running economy (i.e., steady-state oxygen consumption, respiratory exchange ratio, and heart rate) in the absence and presence of IPC. Results: Oxygen uptake at each running velocity was, on average, 1 ml/kg/min lower following IPC (stage 3 IPC: 35.5±1.8 ml/kg/min) compared with the sham control (36.5±2.8 ml/kg/min). Similarly, although not statistical significant given the small sample size, running economy was generally better following IPC. At the highest velocity, IPC running economy was 204±1 ml/kg/km compared with sham (210±8.4 ml/kg/km), a difference of approximately 6 ml of oxygen for every kilometer ran (P=0.18). Moreover, respiratory exchange ratio was significantly lower (P=0.036) in the IPC trial (0.93±0.03) compared with the sham control (0.95±0.03). Lastly, heart rate was 2-7 bpm less with the IPC trials. Conclusions: Our preliminary data shows potential for leg IPC to enhance running economy. However, we are currently increasing the sample size from 5 to 20 subjects before any firm conclusions are drawn. NACSM Professional Sponsor: Gary P. Van Guilde

Effect of physical activity on heart rate variability in normal weight, overweight and obese subjects: results from the SAPALDIA study

Many studies have demonstrated an association of both a sedentary lifestyle and a high body mass index (BMI) with greater risk for cardiovascular disease. Within the prospective SAPALDIA cohort (Swiss cohort Study on Air Pollution and Lung Diseases in Adults), we investigated whether regular exercise was protective against reduced heart rate variability (HRV), a clinically relevant predictor of cardiovascular morbidity and mortality, and whether adverse effects of obesity and weight gain on HRV were modified by regular exercise. Twenty-four-hour electrocardiograms were recorded in 1,712 randomly selected SAPALDIA participants aged >or=50, for whom BMI was assessed in the years 1991 and 2001-2003. Other examinations included an interview investigating health status (especially respiratory and cardiovascular health and health relevant behaviours including physical activity) and measurements of blood pressure, body height and weight. The association between regular physical activity and HRV and interactions with BMI and BMI change was assessed in multivariable linear regression analyses. Compared to sedentary obese subjects, SDNN (standard deviation of all RR intervals) was 14% (95% CI: 8-20%) higher in sedentary normal weight subjects; 19% (CI: 12-27%) higher in normal weight subjects exercising regularly >or=2 h/week; and 19% (CI: 11-28%) higher in obese subjects exercising regularly >or=2 h/week. Compared with sedentary subjects who gained weight, those who gained weight but did exercise regularly had a 13% higher SDNN (CI: 7-20%). Regular physical exercise has strong beneficial effects on cardiac autonomic nervous function and thus appears to offset the negative effect of obesity on HRV