Changes in PPARδ Protein Content following Acute Aerobic Exercise in Human Vastus Lateralis Muscle.

PPARδ is a transcription factor which functions in the regulation of lipid and glucose metabolism, and may be implicated as a therapeutic target for several metabolic diseases. Exercise training has previously been shown to increase PPARδ protein content, but the response of PPARδ to acute exercise is not yet understood. PURPOSE: To explore changes in PPARδ protein content following an acute bout of aerobic exercise in untrained obese adults. METHODS: 8 men and 4 women participated in the study. Subjects’ mean age, weight, VO2MAX (Bruce treadmill GXT), and body composition (DEXA) were 44 yr, 93.2 kg, 28.2 mL/kg/min, and 40.5% body fat, respectively. Subjects were asked to refrain from exercise for 1 week prior to the experiment and to maintain normal dietary habits during the study. Muscle biopsies were obtained from the vastus lateralis 3 days prior to acute exercise and again 24 hours after exercise. Subjects were exercised on a motorized treadmill at 70% VO2MAX for a target duration of 400kcal energy expenditure during the exercise session. PPARδ protein content in biopsied tissue was determined by Western blot analysis. Data were analyzed by repeated measures ANOVA and expressed as means ± standard error. RESULTS: PPARδ content was enhanced 24 hours following acute exercise in previously untrained, obese adults (unexercised 1.54±0.38 vs. exercised 2.30±0.39 arbitrary units, P\u3c0.05). Gel mobility shift indicated no difference in activity of PPARδ (phosphorylated: total) following exercise (unexercised 0.36±0.03 vs. exercised 0.34±0.04). CONCLUSION: Our study shows that PPARδ expression is enhanced in untrained, obese adults following a single bout of aerobic exercise with no relative change in phosphorylation of PPARδ. These data indicate that acute exercise plays a role in the expression of PPARδ. Funding for this research was provided by HydroWorx International, Inc., the Sydney & J.L. Huffines Institute for Sports Medicine and Human Performance at Texas A&M University and The Texas Chapter of The American College of Sports Medicin

Aquatic Treadmill Training Reduces Blood Pressure Reactivity to Acute Graded Exercise in Previously Sedentary Adults

Endurance exercise may reduce blood pressure and improve vasodilatory capacity thereby blunting the hypertensive response to stress. To test the efficacy of a novel model of low-impact endurance training, the aquatic-based treadmill (ATM), to improve blood pressure parameters, we recruited 60 sedentary adults and randomized to 12-weeks of either ATM (n = 36 [19 men, 17 women] , 41±2 yr, 173.58 ±1.58cm, 93.19 ±3.15kg) or land-based treadmill (LTM, n = 24 [11 men, 13 women], 42 ±2yr, 170.39 ±1.94cm, 88.14 ±3.6kg) training; 3sessions·wk-1, progressing to 500 kcal·session-1, 85% VO2max. The maximal Bruce treadmill test protocol was performed before and after training with blood pressures measured prior to, at the end of each stage, and for 5 minutes following exercise testing. Twelve subjects (5 ATM, 7 LTM) volunteered for biopsies of the vastus lateralis before and after training, and muscle samples were assessed for eNOS content. Blood pressure data were analyzed using group by training ANCOVA repeated across training, α = 0.05. Data obtained from muscle sample analysis were analyzed using group by training ANOVA repeated across training α = 0.05. Training reduced systolic blood pressure (9- 18.2mmHg), diastolic blood pressure (3.2-8.1 mmHg), mean arterial pressure (4.8-8.3mmHg), pulse pressure (7.5-15mmHg), and rate pressure product (1.8-3.9 bpm·mm Hg·103) during exercise stress and recovery in the ATM group, but not in the LTM group. Additionally, the ATM group, but not the LTM group, displayed a 31% increase in skeletal muscle eNOS content following training. Both groups improved VO2max (+3.6mL O2·kg-1·min-1), but resting blood pressure was not changed following training. These data support the use of ATM training as a novel therapeutic modality to combat hypertension

Lipid Profiles of American Collegiate Football Athletes in Response to Fall Preseason Camp

Recent studies show former football athletes, especially football linemen, to be at increased cardiovascular disease risk. However, the lipid profiles of American NCAA Football Bowl Subdivision (FBS) players in response to sport participation are currently unknown. PURPOSE: To quantify the effects of participation in fall preseason football training camp on the blood lipid profiles in NCAA FBS athletes. METHODS: Seated venous blood samples were drawn in the morning after an overnight fast from 51 football players (age = 20 ± 2 yr, weight = 232.8 ± 40.8 lb, height = 73.9 ± 2.6 in) and analyzed for total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HLD-C), and triglyceride (TG). Samples were obtained on two separate occasions corresponding to the beginning of fall preseason football camp, and again 16 days later near the end. Data were analyzed by paired t-test. RESULTS: See table, values are means ± SD, * = p ≤ 0.001. Measurement Time Lipid and Lipoprotein Concentrations (mg/dL) TC LDL-C HDL-C TG TC:HDL Ratio Beginning 158 ± 34 90 ± 24 54 ± 15 117 ± 50 3.02 ± 0.70 End 151 ± 35 92 ± 28 47 ± 11* 86 ± 41* 3.32 ± 0.84* CONCLUSION: Participation in fall preseason training camp significantly alters the traditional lipid profiles of Collegiate FBS athletes. These lipid changes suggest a proinflammatory state with high energy utilization, and are consistent with the hypothesis that LDL-C is necessary for the structural repair of damaged tissue

Variable number of tandem repeat polymorphisms of the interleukin-1 receptor antagonist gene IL-1RN: a novel association with the athlete status

<p>Abstract</p> <p>Background</p> <p>The interleukin-1 (IL-1) family of cytokines is involved in the inflammatory and repair reactions of skeletal muscle during and after exercise. Specifically, plasma levels of the IL-1 receptor antagonist (IL-1ra) increase dramatically after intense exercise, and accumulating evidence points to an effect of genetic polymorphisms on athletic phenotypes. Therefore, the IL-1 family cytokine genes are plausible candidate genes for athleticism. We explored whether IL-1 polymorphisms are associated with athlete status in European subjects.</p> <p>Methods</p> <p>Genomic DNA was obtained from 205 (53 professional and 152 competitive non-professional) Italian athletes and 458 non-athlete controls. Two diallelic polymorphisms in the IL-1β gene (<it>IL-1B</it>) at -511 and +3954 positions, and a variable number tandem repeats (VNTR) in intron 2 of the IL-1ra gene (<it>IL-1RN</it>) were assessed.</p> <p>Results</p> <p>We found a 2-fold higher frequency of the <it>IL-1RN </it>1/2 genotype in athletes compared to non-athlete controls (OR = 1.93, 95% CI = 1.37-2.74, 41.0% vs. 26.4%), and a lower frequency of the 1/1 genotype (OR = 0.55, 95% CI = 0.40-0.77, 43.9% vs. 58.5%). Frequency of the <it>IL-1RN </it>2/2 genotype did not differ between groups. No significant differences between athletes and controls were found for either -511 or +3954 <it>IL-1B </it>polymorphisms. However, the haplotype (-511)C-(+3954)T-(VNTR)2 was 3-fold more frequent in athletes than in non-athletes (OR = 3.02, 95% CI = 1.16-7.87). Interestingly, the <it>IL-1RN </it>1/2 genotype was more frequent in professional than in non-professional athletes (OR = 1.92, 95% CI = 1.02-3.61, 52.8% vs. 36.8%).</p> <p>Conclusions</p> <p>Our study found that variants at the IL-1ra gene associate with athletic status. This confirms the crucial role that cytokine IL-1ra plays in human physical exercise. The VNTR <it>IL-1RN </it>polymorphism may have implications for muscle health, performance, and/or recovery capacities. Further studies are needed to assess these specific issues. As VNTR <it>IL-1RN </it>polymorphism is implicated in several disease conditions, athlete status may constitute a confounding variable that will need to be accounted for when examining associations of this polymorphism with disease risk.</p

Acute and chronic safety and efficacy of dose dependent creatine nitrate supplementation and exercise performance

BACKGROUND: Creatine monohydrate (CrM) and nitrate are popular supplements for improving exercise performance; yet have not been investigated in combination. We performed two studies to determine the safety and exercise performance-characteristics of creatine nitrate (CrN) supplementation. METHODS: Study 1 participants (N = 13) ingested 1.5 g CrN (CrN-Low), 3 g CrN (CrN-High), 5 g CrM or a placebo in a randomized, crossover study (7d washout) to determine supplement safety (hepatorenal and muscle enzymes, heart rate, blood pressure and side effects) measured at time-0 (unsupplemented), 30-min, and then hourly for 5-h post-ingestion. Study 2 participants (N = 48) received the same CrN treatments vs. 3 g CrM in a randomized, double-blind, 28d trial inclusive of a 7-d interim testing period and loading sequence (4 servings/d). Day-7 and d-28 measured Tendo™ bench press performance, Wingate testing and a 6x6-s bicycle ergometer sprint. Data were analyzed using a GLM and results are reported as mean ± SD or mean change ± 95 % CI. RESULTS: In both studies we observed several significant, yet stochastic changes in blood markers that were not indicative of potential harm or consistent for any treatment group. Equally, all treatment groups reported a similar number of minimal side effects. In Study 2, there was a significant increase in plasma nitrates for both CrN groups by d-7, subsequently abating by d-28. Muscle creatine increased significantly by d-7 in the CrM and CrN-High groups, but then decreased by d-28 for CrN-High. By d-28, there were significant increases in bench press lifting volume (kg) for all groups (PLA, 126.6, 95 % CI 26.3, 226.8; CrM, 194.1, 95 % CI 89.0, 299.2; CrN-Low, 118.3, 95 % CI 26.1, 210.5; CrN-High, 267.2, 95 % CI 175.0, 359.4, kg). Only the CrN-High group was significantly greater than PLA (p < 0.05). Similar findings were observed for bench press peak power (PLA, 59.0, 95 % CI 4.5, 113.4; CrM, 68.6, 95 % CI 11.4, 125.8; CrN-Low, 40.9, 95 % CI −9.2, 91.0; CrN-High, 60.9, 95 % CI 10.8, 111.1, W) and average power. CONCLUSIONS: Creatine nitrate delivered at 3 g was well-tolerated, demonstrated similar performance benefits to 3 g CrM, in addition, within the confines of this study, there were no safety concerns

The Acute Satellite Cell Response and Skeletal Muscle Hypertrophy following Resistance Training

The extent of skeletal muscle hypertrophy in response to resistance training is highly variable in humans. The main objective of this study was to explain the nature of this variability. More specifically, we focused on the myogenic stem cell population, the satellite cell (SC) as a potential mediator of hypertrophy. Twenty-three males (aged 18–35 yrs) participated in 16 wk of progressive, whole body resistance training, resulting in changes of 7.9±1.6% (range of −1.9–24.7%) and 21.0±4.0% (range of −7.0 to 51.7%) in quadriceps volume and myofibre cross-sectional area (CSA), respectively. The SC response to a single bout of resistance exercise (80% 1RM), analyzed via immunofluorescent staining resulted in an expansion of type II fibre associated SC 72 h following exercise (pre: 11.3±0.9; 72 h: 14.8±1.4 SC/type II fibre; p<0.05). Training resulted in an expansion of the SC pool associated with type I (pre: 10.7±1.1; post: 12.1±1.2 SC/type I fibre; p<0.05) and type II fibres (pre: 11.3±0.9; post: 13.0±1.2 SC/type II fibre; p<0.05). Analysis of individual SC responses revealed a correlation between the relative change in type I associated SC 24 to 72 hours following an acute bout of resistance exercise and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.566, p = 0.012) and the relative change in type II associated SC following 16 weeks of resistance training and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.493, p = 0.027). Our results suggest that the SC response to resistance exercise is related to the extent of muscular hypertrophy induced by training

Relationship of ethnicity and CD4 Count with glucose metabolism among HIV patients on Highly-Active Antiretroviral Therapy (HAART)

Background: HIV patients on HAART are prone to metabolic abnormalities, including insulin resistance, lipodystrophy and diabetes. This study purports to investigate the relationship of ethnicity and CD4+ T cell count attained after stable highly-active antiretroviral treatment (HAART) with glucose metabolism in hyperrtriglyceridemic HIV patients without a history of diabetes. Methods: Demographic, anthropometric, clinical, endocrinologic, energy expenditure and metabolic measures were obtained in 199 multiethnic, healthy but hypertriglyceridemic HIV-infected patients [46% Hispanic, 17% African-American, 37% Non-Hispanic White (NHW)] on stable HAART without a history of diabetes. The relationship of glucose and insulin responses to ethnicity, CD4 strata (low (\u3c 0.05) and HbA1c levels (P \u3c .001) than either Hispanics or NHWs. In multivariate models, after adjusting for confounders (age, sex, HIV/ HAART duration, smoking, obesity, glucose, insulin and lipids), African-Americans and Hispanics had significantly higher HbA1c and 2-hour glucose levels than NHW’s. Demonstrating a significant interaction between ethnicity and CD4 count (P = 0.023), African Americans with CD