Sang Hoon Suh

Improved Insulin Sensitivity and Adiponectin Level after Exercise Training in Obese Korean Youth

Objective: The objective of this study was to investigate the association among adiposity, insulin resistance, and inflammatory markers [high‐sensitivity C‐reactive protein (hs‐CRP), interleukin (IL)‐6, and tumor necrosis factor (TNF)‐α] and adiponectin and to study the effects of exercise training on adiposity, insulin resistance, and inflammatory markers among obese male Korean adolescents.

2014 clinical practice guidelines for overweight and obesity in Korea.

The dramatic increase in the prevalence of obesity and its accompanying comorbidities are major health concerns in Korea. Obesity is defined as a body mass index ≥25 kg/m2 in Korea. Current estimates are that 32.8% of adults are obese: 36.1% of men and 29.7% of women. The prevalence of being overweight and obese in national surveys is increasing steadily. Early detection and the proper management of obesity are urgently needed. Weight loss of 5% to 10% is the standard goal. In obese patients, control of cardiovascular risk factors deserves the same emphasis as weight-loss therapy. Since obesity is multifactorial, proper care of obesity requires a coordinated multidisciplinary treatment team, as a single intervention is unlikely to modify the incidence or natural history of obesity.

Integrative Physiology: Defined Novel Metabolic Roles of Osteocalcin

The prevailing model of osteology is that bones constantly undergo a remodeling process, and that the differentiation and functions of osteoblasts are partially regulated by leptin through different central hypothalamic pathways. The finding that bone remodeling is regulated by leptin suggested possible endocrinal effects of bones on energy metabolism. Recently, a reciprocal relationship between bones and energy metabolism was determined whereby leptin influences osteoblast functions and, in turn, the osteoblast-derived protein osteocalcin influences energy metabolism. The metabolic effects of bones are caused by the release of osteocalcin into the circulation in an uncarboxylated form due to incomplete γ-carboxylation. In this regard, the Esp gene encoding osteotesticular protein tyrosine phosphatase is particularly interesting because it may regulate γ-carboxylation of osteocalcin. Novel metabolic roles of osteocalcin have been identified, including increased insulin secretion and sensitivity, increased energy expenditure, fat mass reduction, and mitochondrial proliferation and functional enhancement. To date, only a positive correlation between osteocalcin and energy metabolism in humans has been detected, leaving causal effects unresolved. Further research topics include: identification of the osteocalcin receptor; the nature of osteocalcin regulation in other pathways regulating metabolism; crosstalk between nutrition, osteocalcin, and energy metabolism; and potential applications in the treatment of metabolic diseases.

The effects of aerobic exercise training on serum osteocalcin, adipocytokines and insulin resistance on obese young males

Osteocalcin has been proposed to be a novel link between bone and energy metabolism. Previous studies showed its relations to exercise, body fat and glucose metabolism, but their interrelationship remains inconslusive. We evaluated the changes in osteocalcin level following 8‐week exercise programme and assessed how they are related to concomitant changes in body fat composition, insulin resistance and various adipocytokines in a single centre, randomized and prospective design.

Effects of Exercise on Insulin, IGF-axis, Adipocytokines, and Inflammatory Markers in Breast Cancer Survivors: A Systematic Review and Meta-Analysis.

Background: Insulin, IGF axis, adiponectin, and inflammatory markers are associated with breast cancer. Given that physical activity improves prognosis of breast cancer survivors, we investigated the effects of exercise on these markers as potential mediators between physical activity and breast cancer. Methods: PubMed, EMBASE, CENTRAL, CINAHL, and SportDiscus were searched up to December 3, 2015, to identify randomized controlled trials (RCT) that investigated the effect of exercise on insulin, IGF axis, and cytokines in breast cancer survivors. Weighted mean difference (WMD) was calculated using either fixed- or random-effects models on the basis of the heterogeneity of the studies. Results: A total of 18 studies involving 681 breast cancer survivors were included, and these numbers were reduced for individual biomarker analyses. We found that exercise significantly reduced fasting insulin levels [WMD, −3.46 μU/mL; 95% confidence interval (CI), −5.97 to −0.95; P = 0.007]. Furthermore, potentially meaningful but statistically nonsignificant changes were observed in insulin resistance (WMD, −0.73; 95% CI, −0.54 to 0.13; P = 0.23), adiponectin (WMD, 1.17 μg/mL; 95% CI, −0.87 to 3.20; P = 0.26), and C-reactive protein (WMD, −1.10 mg/L; 95% CI, −2.39 to 0.20; P = 0.10). Subgroup analyses showed that fasting insulin levels were significantly more impacted in studies in which intervention participants experienced a weight reduction (WMD, −7.10 μU/mL; 95% CI, −10.31 to −3.90; P < 0.001). Conclusions: Exercise reduces fasting insulin levels in breast cancer survivors. This may be due to exercise-induced reductions in body weight. Impact: Practitioners and clinicians may better help breast cancer prognosis be improved through exercise, anticipating physiological effects on cancer. Cancer Epidemiol Biomarkers Prev; 26(3); 355–65. ©2016 AACR.

Association between cardiorespiratory fitness and the prevalence of metabolic syndrome among Korean adults: a cross sectional study

BackgroundThe purpose of the current study was to investigate the association between cardiorespiratory fitness (CRF), measured by a simple step test, and the prevalence of metabolic syndrome among Korean adults, in a cross sectional design.MethodsA total of 1,007 Korean adults (488 men and 519 women) who underwent routine health checkups were recruited. CRF was measured by Tecumseh step test. The National Cholesterol Education Program’s Adult Treatment Panel III guideline was used to determine the prevalence of metabolic syndrome. A logistic regression was performed to reveal possible associations.ResultsThe results of the study showed that a lower level of CRF was significantly associated with a higher prevalence of metabolic syndrome in men, but not in women. On the other hand, higher BMI was associated with a higher prevalence of metabolic syndrome in both men and women. However, BMI was not associated with fasting glucose nor hemoglobinA1c in men. When the combined impact of BMI and CRF on the prevalence of metabolic syndrome was analyzed, a significantly increased prevalence of metabolic syndrome was found in both men (odds ratio [OR]: 18.8, 95% Confidence Interval [CI]: 5.0 - 70.5) and women (OR: 8.1, 95% CI: 2.8 - 23.9) who had high BMI and low cardiorespiratory fitness. On the other hand, the prevalence of metabolic syndrome was only increased 7.9 times (95% CI: 2.0 - 31.2) in men and 5.4 times (95% CI: 1.9 - 15.9) in women who had high level of CRF and high BMI.ConclusionIn conclusion, the current study demonstrated the low CRF and obesity was a predictor for metabolic syndrome in Korean adults.

Effects of Fluid Ingestion on Brain-Derived Neurotrophic Factor and Cognition During Exercise in the Heat

Abstract We investigated the effects of fluid ingestion during exercise in different environments on the serum brain-derived neurotrophic factor and cognition among athletes. Ten collegiate male athletes (soccer, n = 5; rugby, n = 5) were enrolled, and they completed running tests in the following four conditions (60 min each): 1) thermoneutral temperature at 18°C (group 18); 2) high ambient temperature at 32°C without fluid ingestion (group 32); 3) high ambient temperature at 32°C with water ingestion (group 32+W); and 4) high ambient temperature at 32°C with sports drink ingestion (group 32+S). Serum brain-derived neurotrophic factor levels significantly increased in group 18 immediately after exercise when compared with those at rest and were significantly higher than those in group 32 immediately and 60 min after exercise (p < 0.05). In the Stroop Color and Word Test, significantly increased Word, Color, and Color-Word scores were observed in group 18 immediately after exercise compared to those at rest (p < 0.05). However, the Color-Word score appeared to be significantly lower in group 32 immediately after exercise compared to the other groups (p < 0.05) and at 60 min post-exercise compared to group 18 (p < 0.05). We found that the exercise performed in a thermoneutral environment improved cognitive function, but the exercise performed in a hot environment did not. The differences according to the exercise environment would be largely affected by brain-derived neurotrophic factor, and fluid ingestion regardless of the type of drink (water or sports beverage) was assumed to have contributed to the improvement in cognitive function caused by exercising in a hot environment.

Effects of different fluid replacements on serum HSP70 and lymphocyte DNA damage in college athletes during exercise at high ambient temperatures

Purpose The aim of this study was to investigate the effects of fluid replacement by water or sports drinks on serum heat shock protein 70 (HSP70) levels and DNA damage during exercise at a high ambient temperature. Methods Ten male college athletes with an athletic career ranging from 6 to 11 years were recruited from Yonsei University. The subjects ran on a treadmill at 75% of heart rate reserve during 4 different trials: thermoneutral temperature at 18°C (T), high ambient temperature at 32°C without fluid replacement (H), high ambient temperature at 32°C with water replacement (HW), and high ambient temperature at 32°C with sports drink replacement (HS). During each condition, blood samples were collected at the pre-exercise baseline (PEB), immediately after exercise (IAE), and 60 min post-exercise. Results Skin temperature significantly increased during exercise and was significantly higher in H compared to T and HS at IAE. Meanwhile, serum HSP70 was significantly increased in all conditions at IAE compared to PEB and was higher in H compared to T at the former time point. Significantly increased lymphocyte DNA damage (DNA in the tail, tail length, tail moment) was observed in all trials at IAE compared to PEB, and attenuated DNA damage (tail moment) was observed in HS compared to H at IAE. Conclusion Acute exercise elevates serum HSP70 and induces lymphocyte DNA damage. Fluid replacement by sports drink during exercise at high ambient temperature can attenuate HSP response and DNA damage by preventing dehydration and reducing thermal stress.