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Symposia Speakers

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In Kyu Lee
Date
June 16, 2016 17:00
Speaker
In Kyu Lee   CV
Affiliation
Kyungpook National University
Title
Role of PDK (Pyruvate Dehydrogenase Kinase) in muscle insulin resistance
Abstract

Obesity is associated with reduced insulin sensitivity which plays a major role in development of type 2 diabetes. Overnutrition induces drastic change in the cellular metabolism that affects normal function of Endoplasmic-reticulum (ER) and mitochondria which exacerbates the cellular response to insulin. Although, ER and mitochondria have its own distinct role in regulating cellular homeostasis but these organelles also physically interact with each other to exchange calcium, lipids and other metabolites to maintain cellular bioenergetics. This juxtaposition of ER and mitochondrial is known as Mitochondria associated ER membrane (MAM). MAM localized proteins IP3R1, GRP75 and VDAC form a protein complex and regulates calcium transfer from ER to mitochondria. Previously, calcium accumulation in mitochondria due to abnormal induction of MAM formation was observed in hepatic tissue of diet induced and genetically obese mice whereas suppression of MAM formation improved hepatic insulin sensitivity in those mice. On the other hand, Pyruvate dehydrogenase kinase 4(PDK4) which regulate conversion of pyruvate to acetyl CoA by inactivating pyruvate dehydrogenase activity is highly upregulated in skeletal muscle during obesity and diabetes.
In this study, we examine the role of PDK4 in regulating MAM formation and its contribution in development of insulin resistance in skeletal muscle. Interestingly, we found that PDK4 is localized in MAM and stimulated MAM formation by physically interacting with IP3R1, GRP75 and VDAC at mitochondria-ER interface. Induction of insulin resistance by high fat feeding upregulated PDK4 protein level and stimulated MAM formation in mice skeletal muscle. Finally, PDK4 deficiency suppressed MAM formation and improved insulin sensitivity in diet induced obese mice skeletal muscle. These findings revealed new insights of PDK4 and its role in triggering obesity induced insulin resistance.

 

Yanh Ha Kim
Date
June 16, 2016 17:15
Speaker
Yanh Ha Kim   CV
Affiliation
Ewha Women University
Title
Phytonutrient increases mitochondrial biogenesis with AMPK activation in high-fat diet-induced obese rats
Abstract

Obesity comes from a long-term positive energy imbalance. It is often accompanied with high blood pressure, high blood cholesterol, type 2 diabetes, coronary heart disease, and other metabolic diseases. Decreased mitochondrial number and dysfunction in skeletal muscle are associated with obesity and the progression of obesity-associated metabolic disorders. Rutin is a flavonoid glycoside which is mainly distributed in buckwheat. Beneficial effects of rutin in inflammation, atherosclerosis, and oxidative stress have been reported. The specific aim of the current study was to investigate the effects of rutin on mitochondrial biogenesis and AMPK activity in skeletal muscles of high-fat diet-induced obese rats. A total of 24 male Sprague-Dawley rats (3-week-old) were randomly divided into three groups (n = 8/group) and fed a normal diet (NOR), a high-fat diet (HFD) or a 0.1% (wt:wt) rutin-supplemented high-fat diet (HFD + Rutin) for 12 weeks. Rutin reduced body weight and adipose tissue mass. Rutin significantly increased mirochondrial size and mitochondrial DNA content as well as gene expression related to mitochondrial biogenesis, such as peroxisome proliferator-activated receptor coactivator-1α (PGC-1α), nuclear respiratory factor-1 (NRF-1), transcription factor A (Tfam), and nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, sirtulin1 (SIRT1) in skeletal muscle (p < 0.05). Specifically, AMPK activity in muscle of rats supplemented with rutin was higher by 40%, compared to that of HF group (p < 0.05). These results suggest that the rutin might be a promising agent protecting against high-fat diet-induced obesity and mitochondrial dysfunction in skeletal muscle.

Key words: rutin, obesity, mitochondrial function, AMPK, skeletal muscle

 

Sung Joon Kim
Date
June 16, 2016 17:25
Speaker
Sung Joon Kim   CV
Affiliation
Seoul National University
Title
Loss of myogenic response and changes in the ion channel currents in hind limb paralyzed skeletal arteries and their recovery by exercise training
Abstract

K+ channel currents such as voltage-gated K+ current (IKv) and inwardly rectifying K+ current (IKir) set the negative membrane potential of arterial myocytes, counterbalances the voltage-operated Ca2+ currents (ICa,L). In the rats underwent endurance exercise training (ET, rodent treadmill running) for two weeks, both IKv and IKir in skeletal arterial smooth muscle cells (SkASMC) are significantly increased. When unilateral sciatic nerve was severed to induce lower hindlimb paralysis and atrophy, both IKir and IKv were decreased in the side-specific manner. When two to four weeks of ET was combined with the sciatic nerve injury model, both IKv and IKir were recovered. We also found that the myogenic response (pressure-induced vasoconstriction) of deep femoral arteries were impaired in the paralyzed hindlimb while intact in the contralateral hindlimb. Consistently, ICa,L was decreased in the paralyzed SkASMCs. The ET recovered both the myogenic response and ICa,L. Our present study showed multiple beneficial effects of ET on the physiology of skeletal arteries even in the paralyzed limbs. The recovery of MR in skeletal arteries would be helpful for the regulation of blood pressure as well as the regional blood flow control.

 

Chang Keun Kim
Date
June 16, 2016 17:35
Speaker
Chang Keun Kim   CV
Affiliation
Korea National Sport University
Title
Effects of ice application on nutritive blood flow and local metabolic response in skeletal muscle after resistance exercise
Abstract

1Ageing Research Institute, Korean National Sport University, Seoul, Korea. 2Human Performance Laboratory, Department of Kinesiology, College of Health and Human Performance, 3Department of Physiology, Brody School of Medicine, 4Center for Health Disparities, East Carolina University, Greenville, NC, USA, 5School of Health Sciences, University of KwaZulu-Natal, Durban, S. Africa

Icing of a limb for therapeutic relief from pain due to strenuous exercise or muscle injury is commonly practiced by the layperson and professionals in medical, sport and recreation fields. The assumptions made as to the therapeutic effect, some supported by research and others not, are that icing results in pain relief, reduced edema, quicker recovery and lower blood flow in the iced area. Most previous studies of cooling effects in humans have been performed on resting limbs that have not recently performed exercise. Therefore, we tried to determine if icing the thigh after a strenuous bout of resistance exercise lowers nutritive blood flow and alters fat and carbohydrate metabolism in the underlying muscle tissue. Microdialysis probes were inserted bilaterally into the vastus lateralis muscles of nine active college-aged men after an exercise bout (10 sets of knee extension exercise at 10-RM max) to monitor microvascular blood flow and metabolism before (40 min), during (30 min) and after (50 min) local cooling. Following the icing period, there was a significantly decrease in both dialysate glucose and dialysate glycerol in the cooled leg. There were no changes from baseline in microvascular blood flow. Icing of the thigh one hour after resistance exercise is completed does not alter nutritive blood flow. However, there is a beta-adrenoceptor-mediated reduction in dialysate glucose and a non-adrenergically-mediated reduction in dialysate glycerol (lipolysis) following the cooling period.


Key words: adrenergic, cooling, exercise, glucose, glycerol, microdialysis

 

Sae Young Jae
Date
June 16, 2016 17:45
Speaker
Sae Young Jae   CV
Affiliation
University of Seoul
Title
Exercise heart rate reserve and recovery as predictors of incident type 2 diabetes
Abstract

1Department of Sport Science, University of Seoul, Seoul, South Korea. 2Department of Medicine, Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland. 3 Diabetes Research Centre, Leicester General Hospital, Leicester, UK. 4Center for Health Promotion, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea. 5Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL, USA. 6Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. 7Preventive Cardiology and Cardiac Rehabilitation, William Beaumont Hospital, Royal Oak, MI, USA.


We tested the hypothesis that selected exercise heart rate responses, specifically those providing indices of autonomic dysfunction, are associated with incident type 2 diabetes in 2231 healthy men with normal baseline fasting glucose levels. Heart rate reserve was calculated as the difference between the maximal attained heart rate and the supine resting heart rate, while heart rate recovery was defined as the maximal heart rate minus 2-min heart rate recovery after exercise testing. Type 2 diabetes was defined as HbA1c>6.5% and/or fasting plasma glucose >126mg/dl at follow-up examination. During a median follow-up interval of 5 years, 90 (4.0%) men developed type 2 diabetes. The relative risks (RRs) of incident type 2 diabetes in men within the lowest quartiles of heart rate reserve and heart rate recovery versus men comprising the highest quartiles of heart rate reserve and heart rate recovery were 2.91 (95% CI, 1.30-6.53) and 2.42 (95% CI, 1.20-4.85) after adjusting for potential confounding variables. Each unit increment (1 beat/min) in heart rate reserve and heart rate recovery was associated with a 2~3% decreased incidence of type 2 diabetes. Exercise heart rate reserve and recovery predicted incidence of type 2 diabetes, suggesting that autonomic dysfunction may be associated with an increased risk for the development of type 2 diabetes


Key words: Exercise, heart rate reserve, heart rate recovery, type 2 diabetes

 

Wang lok Lee
Date
June 16, 2016 17:55
Speaker
Wang lok Lee   CV
Affiliation
Chungnam National University
Title
Moderate exercise training alleviates obese-induced metabolic complication by inhibition of macrophage infiltration and inflammation production in adipocytes
Abstract

This study was investigated to determine the effect of moderate exercise training on obese-induced metabolic complication by inhibition of macrophage infiltration and inflammation production in adipocytes. C57BL/6 mice were separated into 5 groups: normal diet (ND; n = 6), high-fat diet (HD; n = 6), high-fat diet with resveratrol (HR; n = 6), high-fat diet with exercise (HE; n = 6) or high-fat diet with resveratrol and exercise (HRE; n = 6). Resveratrol supplementation mice were orally gavaged with resveratrol (25mg/kg of body weight) dissolved in 50% propylene glycol. Exercise mice ran on a treadmill at 12-20 m/min for 30-60 min/day, 5 times/week for 12 weeks. After 12 weeks of intervention, the liver was analyzed. F4/80 expression was evaluated by western blot while CD11c and CD163 mRNA expressions were evaluated by RT-PCR. The weights of the body and liver were significantly increased in the HD and HR group compared to the ND group (p < 0.01). However, the weights were most effectively reduced in the HE and HRE groups compared to the HD group (p < 0.05). The macrophage marker, F4/80 expression was significantly lower in the HE and HRE groups compared to the HD group (p < 0.05). mRNA expression of the M1 macrophage marker, CD11c, in the HD group was significantly increased compared to the ND group (p < 0.01). mRNA expression of the M2 macrophage specific marker, CD163, in the HE and HRE groups were significantly increased compared to the HD group (p < 0.05). The mRNA expressions of TLR4, ICAM-1 and VCAM-1, which induce pro-inflammatory cytokine production, were strongly decreased in the HR, HE, and HRE groups compared to the HD group. These findings suggest that moderate exercise training has beneficial effects to inhibit adipose tissue remodeling and macrophage infiltration in high fat diet-induced obese mice.
Key words : high-fat diet, moderate exercise, adipocyte, macrophage infiltration, inflammation.

 

Yoon Suk Jekal
Date
June 16, 2016 18:05
Speaker
Yoon Suk Jekal   CV
Affiliation
Jeju National University
Title
Correlates of children obesity
Abstract

Key words: children, correlates, obesity

Children and adolescents obesity has more than doubled and quadrupled in the last decades. Since childhood obesity has both immediate and long-term effects on health and well-being across lifetime, preventing childhood obesity is one of the most priorities in public health field.
Jeju Special Self-Governing Province has been suffering from increasing prevalence of children and adolescents’ obesity, and the determinants or correlates of childhood obesity were investigated in 2015. Date in Korean Youth Risk Behavior On-Line Survey ware analyzed, and an analysis on primary factor and case-control investigation were conducted.
In results, youth in Jeju were more likely to consume ramens, fast-foods or meats (three or more time per week), however, they were less likely to consume vegetables and fruits. In addition, there were numerous children and adolescents who have meats every day. Youth at risk of overweight or obesity were less likely to engage in enough sleeping hours and physical activity time. Youth with parents who engaged in unhealthy behaviors such as binge drinking, smoking, sedentary were more likely to be at risk of overweight or obesity. The level of children obesity was significantly related to the level of parents’ obesity, in particular, mother’s.
The current investigation suggests a family-based model for childhood obesity intervention rather than an individual-approach model