Successive bouts of cycling stimulates genes associated with mitochondrial biogenesis.

Exercise increases mRNA for genes involved in mitochondrial biogenesis and oxidative enzyme capacity. However, little is known about how these genes respond to consecutive bouts of prolonged exercise. We examined the effects of 3 h of intensive cycling performed on three consecutive days on the mRNA associated with mitochondrial biogenesis in trained human subjects. Forty trained cyclists were tested for VO(2max) (54.7 +/- 1.1 ml kg(-1) min(-1)). The subjects cycled at 57% watts(max) for 3 h using their own bicycles on CompuTrainer Pro Model trainers (RacerMate, Seattle, WA) on three consecutive days. Muscle biopsies were obtained from the vastus lateralis pre- and post-exercise on days one and three. Muscle samples were analyzed for mRNA content of peroxisome proliferator receptor gamma coactivator-1 alpha (PGC-1alpha), sirtuin 1 (Sirt-1), cytochrome c, and citrate synthase. Data were analyzed using a 2 (time) x 2 (day) repeated measures ANOVA. Of the mRNA analyzed, the following increased from pre to post 3 h rides: cytochrome c (P = 0.006), citrate synthase (P = 0.03), PGC-1alpha (P < 0.001), and Sirt-1 (P = 0.005). The following mRNA showed significant effects from days one to three: cytochrome c (P < 0.001) and citrate synthase (P = 0.01). These data show that exhaustive cycling performed on three consecutive days resulted in both acute and chronic stimuli for mRNA associated with mitochondrial biogenesis in already trained subjects. This is the first study to illustrate an increase in sirtuin-1 mRNA with acute and chronic exercise. These data contribute to the understanding of mRNA expression during both acute and successive bouts of prolonged exercise.

Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA.

Trained male cyclists (n = 40) ingested quercetin (Q; n = 20) (1,000 mg/day) or placebo (P; n = 20) supplements under randomized, double-blinded methods for 3 wk before and during a 3-day period in which subjects cycled for 3 h/day at approximately 57% maximal work rate. Blood samples were collected before and after each exercise session and assayed for plasma IL-6, IL-10, IL-1ra, IL-8, TNF-alpha, and monocyte chemoattractant protein 1, and leukocyte IL-10, IL-8, and IL-1ra mRNA. Muscle biopsies were obtained before and after the first and third exercise sessions and assayed for NF-kappaB and cyclooxygenase-2 (COX-2), IL-6, IL-8, IL-1beta, and TNF-alpha mRNA. Postexercise increases in plasma cytokines did not differ between groups, but the pattern of change over the 3-day exercise period tended to be lower in Q vs. P for IL-8 and TNF-alpha (P = 0.094 for both). mRNA increased significantly postexercise for each cytokine measured in blood leukocyte and muscle samples. Leukocyte IL-8 and IL-10 mRNA were significantly reduced in Q vs. P (interaction effects, P = 0.019 and 0.012, respectively) with no other leukocyte or muscle mRNA group differences. Muscle NF-kappaB did not increase postexercise and did not differ between Q and P. Muscle COX-2 mRNA increased significantly postexercise but did not differ between Q and P. In summary, 1 g/day quercetin supplementation by trained cyclists over a 24-day period diminished postexercise expression of leukocyte IL-8 and IL-10 mRNA, indicating that elevated plasma quercetin levels exerted some effects within the blood compartment. Quercetin did not, however, influence any of the muscle measures, including NF-kappaB content, cytokine mRNA, or COX-2 mRNA expression across a 3-day intensified exercise period.

C-reactive protein levels in African Americans: a diet and lifestyle randomized community trial.

BACKGROUND: Chronic inflammation is linked to poor lifestyle behaviors and a variety of chronic diseases that are prevalent among African Americans, especially in the southeastern U.S. PURPOSE: The goal of the study was to test the effect of a community-based diet, physical activity, and stress reduction intervention conducted in 2009-2012 on reducing serum C-reactive protein (CRP) in overweight and obese African-American adults. METHODS: An RCT intervention was designed jointly by members of African-American churches and academic researchers. In late 2012, regression (i.e., mixed) models were fit that included both intention-to-treat and post hoc analyses conducted to identify important predictors of intervention success. Outcomes were assessed at 3 months and 1 year. RESULTS: At baseline, the 159 individuals who were recruited in 13 churches and had evaluable outcome data were, on average, obese (BMI=33.1 [±7.1]) and had a mean CRP level of 3.7 (±3.9) mg/L. Reductions were observed in waist-to-hip ratio at 3 months (2%, p=0.03) and 1 year (5%, p<0.01). In female participants attending ≥60% of intervention classes, there was a significant decrease in CRP at 3 months of 0.8 mg/L (p=0.05), but no change after 1 year. No differences were noted in BMI or interleukin-6. CONCLUSIONS: In overweight/obese, but otherwise "healthy," African-American church members with very high baseline CRP levels, this intervention produced significant reductions in CRP at 3 and 12 months, and in waist-to-hip ratio, which is an important anthropometric predictor of overall risk of inflammation and downstream health effects. TRIAL REGISTRATION: This study is registered at www.clinicaltrials.gov NCT01760902.