Tae-Kyung Han

Relationship of PGC-1α Gene Polymorphism With Insulin Resistance Syndrome in Korean Children:

This study aimed to investigate the associations between peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) gene Gly482Ser polymorphism (rs8192678) and parameters of insulin resistance in a sample of Korean children. A total of 286 children aged 10 to 12 years old were recruited from local elementary schools. Measured variables included body fat, blood pressures, blood lipids, glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and accelerometer-based physical activity (PA). Significant differences in percentage body fat (P = .016), insulin (P = .013), and HOMA-IR (P = .007) were found according to Gly482Ser genotype, with no significant genotype differences in the other measured variables. The genotype-specific differences in insulin (P = .136) and HOMA-IR (P = .067) were significantly attenuated when adjusted for age, sex, Tanner stage, body fat, and PA. The findings of the study suggest that the genetic effects of the PGC-1α genotypes on parameters of insulin resistance might be modulated by lifestyle factors, including PA and body fatness.

Aerobic training increases the expression of adiponectin receptor genes in the peripheral blood mononuclear cells of young men

Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis.

Association between serum vitamin D status and metabolic syndrome in Korean young men.

PURPOSE This study examined the relations of serum vitamin D levels to body fatness, cardiorespiratory fitness (CRF), and metabolic risk factors in young adults in Korea. METHODS Between 2007 and 2009, 799 young men completed a health examination. Body fatness, CRF based on a maximal treadmill exercise test, and measurements of metabolic risk factors were measured in study participants. Participants were classified by serum vitamin D levels as deficient (<12.5 ng·mL), insufficient (≥12.5 to <20 ng·mL), and sufficient (>20 ng·mL) and by CRF as unfit (lowest 20%) and fit (remaining 80%) based on age-standardized distribution of V˙O2max values in this study population. Body fatness, CRF, and metabolic risk factors were evaluated according to serum vitamin D classification. A clustered metabolic risk score was computed by summing standardized scores for waist circumference, resting blood pressures, triacylglycerols, the inverse of high-density lipoprotein cholesterol, glucose, and insulin. RESULTS Linear decreases in body fatness and metabolic risk factors were observed, as was a linear increase for CRF across incremental vitamin D categories. A linear decrease was found in the clustered metabolic risk score across incremental vitamin D categories. Compared to the fit group (reference), the unfit group had significantly higher risks for serum vitamin D inadequacy before and after adjusting for age, smoking, and body fatness parameters. CONCLUSIONS The findings of the study suggest that increasing vitamin D intake, eating a healthy diet, and getting enough outdoor physical activity should be promoted as nonpharmacologic means to improve CRF and prevent a clustering of metabolic risk factors in young adults.