Inhwan Lee

Effect of aerobic exercise training on non-alcoholic fatty liver disease induced by a high fat diet in C57BL/6 mice

[Purpose] The aim of this study was to investigate the effects of aerobic exercise training on a high fat diet (HFD)-induced fatty liver and its metabolic complications in C57BL/6 mice. [Methods] Mice at 5-month old (n = 30) were randomly assigned to standard chow (SC + CON, n = 10) and high-fat diet (HFD, n = 20), and they were subjected to SC and HFD, respectively, for 23-week. After 15-week of HFD, mice in the HFD group were further assigned to HFD (HFD + CON, n = 10) or exercise training (HFD + EX, n = 10) groups. The HFD + EX mice were subjected to aerobic treadmill running during the last 8-week of the 23-week HFD course. Outcomes included hepatic steatosis, insulin resistance, and expression of genes involved in mitochondrial function and/or fatty oxidation as well as de novo lipogenesis and/or triacylglycerol (TAG) synthesis. [Results] Treadmill running ameliorated impaired glucose tolerance and insulin resistance secondary to the HFD. The beneficial effects of treadmill running were associated with enhanced molecular markers of mitochondrial function and/or fatty acids oxidation (i.e., PPARα and CPT1a mRNAs, pAMPK/AMPK, pACC, and SIRT1 protein) as well as suppressed expression of de novo lipogenesis and/or TAG synthesis (i.e., SREBP1c, lipin1 and FAS mRNAs) in the liver. [Conclusion] The current findings suggest that aerobic exercise training is an effective and non-pharmacological means to combat fatty liver and its metabolic complications in HFD-induced obese mice.

Treadmill Running Reverses Cognitive Declines due to Alzheimer Disease.

PURPOSE This study investigated the effect of treadmill running on cognitive declines in the early and advanced stages of Alzheimer disease (AD) in 3xTg-AD mice. METHODS At 4 months of age, 3xTg-AD mice (N = 24) were assigned to control (AD + CON, n = 12) or exercise (AD + EX, n = 12) group. At 24 months of age, 3xTg-AD mice (N = 16) were assigned to AD + CON (n = 8) or AD + EX (n = 8) group. The AD + EX mice were subjected to treadmill running for 12 wk. At each pathological stage, the background strain mice were included as wild-type control (WT + CON, n = 8-12). RESULTS At the early stage of AD, 3xTg-AD mice had impaired short- and long-term memory based on Morris water maze along with higher cortical Aβ deposition, higher hippocampal and cortical tau pathology, and lower hippocampal and cortical PSD-95 and synaptophysin. A 12-wk treadmill running reversed the impaired cognitive declines and significantly improved the tau pathology along with suppression of the decreased PSD-95 and synaptophysin in the hippocampus and cortex. At the advanced stage of AD, 3xTg-AD mice had impaired short- and long-term memory along with higher levels of Aβ deposition, soluble Aβ1-40 and Aβ1-42, tau pathology, and lower levels of brain-derived neurotrophic factor, PSD-95, and synaptophysin in the hippocampus and cortex. A 12-wk treadmill running reversed the impaired cognitive declines and significantly improved the Aβ and tau pathology along with suppression of the decreased synaptic proteins and brain-derived neurotrophic factor in the hippocampus and cortex. CONCLUSIONS The current findings suggest that treadmill running provides a nonpharmacological means to combat cognitive declines due to AD pathology.

ACTN3 Gene and Susceptibility to Sarcopenia and Osteoporotic Status in Older Korean Adults

Background Little information is available about molecular markers for sarcopenia and osteoporosis in Asian populations. Objective This study investigated the association of the ACTN3 polymorphism with sarcopenia and osteoporotic status in older Korean adults. Methods Older Korean 62 men and 270 women (mean age 73.7 ± 6.6 years) participated in this study. Body mass index, percent body fatness, appendicular skeletal muscle mass, and bone mineral density of the lumbar spine, femur, and total body were analyzed with dual-energy X-ray absorptiometry. ACTN3 R/X genotyping was determined using TaqMan probes. Results Determination of odds ratios (ORs) and 95% confidence intervals (CIs) using binary logistic regression analyses showed that XX homozygotes were at a significantly higher risk of sarcopenia (OR = 2.056, 95%  CI = 1.024–4.127, p = 0.043) and osteoporosis (OR = 2.794, 95%  CI = 1.208–5.461, p = 0.016) than RR homozygotes (reference group, OR = 1). The OR of XX homozygotes for having sarcopenia remained significant (OR = 2.237, 95%  CI = 1.044–4.836, p = 0.038) after adjustments for age, gender, body fatness, and serum vitamin D. The OR of XX homozygotes for having osteoporosis was no longer significant (OR = 2.682, 95%  CI = 0.960–7.942, p = 0.075) after adjustments for the covariates. Conclusion Our findings suggest that the ACTN3 R577X genotype may influence decline in muscle and bone health phenotypes in older Korean adults.

Socioeconomic Status, Frailty, and All-Cause Mortality in Korean Older Adults: A 3-Year Population-Based Prospective Study

Background Little is known regarding the effects of socioeconomic status (SES) and frailty on mortality in Korea. Objective This study investigated the combined impact of low SES and frailty on all-cause mortality in Korean older adults. Methods Study sample at baseline comprised 7,960 community-dwelling adults (56.8% women) aged 65 years and older. The Cox proportional hazards model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) of low SES and frailty for all-cause mortality. Results Overall, low SES plus frailty resulted in an increased risk of all-cause mortality (HR = 1.56, 95% CI = 1.09–2.23, P = 0.015) even after adjustments for all the measured covariates, as compared with high SES plus nonfrailty (HR = 1). Among older adults aged 65–75 years, the increased mortality risk of either low SES plus nonfrailty (HR = 1.37, 95% CI = 1.02–1.84, P = 0.038) or high SES plus frailty (HR = 2.09, 95% CI = 1.12–3.91, P = 0.021) remained significant even after adjustments for all the covariates, as compared with high SES plus nonfrailty (HR = 1). Conclusion The current findings suggest that either low SES or frailty is significantly associated with increased all-cause mortality in Korean older adults.

Physical inactivity and cognitive impairment in Korean older adults: gender differences in potential covariates

Abstract Background: Physical inactivity is one major lifestyle risk factor of mild cognitive impairment with ageing. Aim: To investigate whether or not potential covariates modulate the association between physical activity (PA) and cognitive impairment in older adults. Subjects and methods: Data from 10 245 Korean older adults (5817 women) were used. Results: High PA older adults were younger and longer educated and had lower comorbidity and depression than low PA older adults. Compared with low PA men, moderate PA men only had a significantly lower odds-ratio (OR) and 95% confidence interval (95% CI) (OR = 0.795, 95% CI = 0.654 ∼ 0.965, p = 0.021) for having cognitive impairment, even after adjusting for measured covariates, which was no longer significant when additionally adjusted for comorbidity (OR = 0.862, 95% CI = 0.707 ∼ 1.051, p = 0.143). Compared with low PA women, moderate and high PA women had significantly lower risks of cognitive impairment (OR = 0.830, 95% CI = 0.712 ∼ 0.969, p = 0.018 and OR = 0.784, 95% CI = 0.651 ∼ 0.943, p = 0.010, respectively), even after adjusting for the measured covariates including comorbidity, which was no longer significant when additionally adjusted for depression (OR = 0.897, 95% CI = 0.776 ∼ 1.049, p = 0.173 and OR = 0.919, 95% CI = 0.761 ∼ 1.111, p = 0.385, respectively). Conclusion: These findings suggest that gender differences in the covariates modulate the relationship between physical activity and cognitive decline in older Korean adults.

Depressive symptoms and all-cause mortality in Korean older adults: A 3-year population-based prospective study: Mental health and mortality

To examine the association between depressive symptoms and all‐cause mortality in a population‐based prospective study.

Association between Obesity and Carotid Intima-Media Thickness in Korean Office Workers: The Mediating Effect of Physical Activity

Background Obesity and physical inactivity are associated with higher prevalence of cardiovascular disease (CVD). Objective This study investigated the association between obesity and carotid intima-media thickness (CIMT) stratified by physical activity (PA) in Korean office workers. Methods Data obtained from 914 office workers aged 21-60 years (347 women) were used. Resting blood pressures, body mass index (BMI), and waist-to-height ratio (WHtR) were measured. PA was assessed using the international physical activity questionnaire. CIMT was assessed with a carotid artery ultrasonography. Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) of obesity stratified by weekly PA for an abnormally increased CIMT. Results Logistic regression analyses showed that those who were overall obese (OR=2.50, 95% CI=1.60-3.91, P<0.001) or central obese (OR=2.08, 95% CI=1.29-3.40, P=0.003) had significantly higher estimated risks of having an abnormally increased CIMT even after adjustments for age, sex, smoking, alcohol consumption, resting blood pressures, and history of hypertension, diabetes, and hyperlipidemia, as compared with those who were not overall or central obese (OR=1). A multivariate linear regression suggested that age (P<0.001), sex (P=0.002), hypertension (P=0.014), smoking (P=0.054), BMI (P<0.001), and physical activity (P=0.011) were important determinants of abnormally elevated CIMT in this study population. Conclusion The current findings suggest that the risk of obesity for an abnormally increased CIMT is significantly modulated by demographics as well as lifestyle-related risk factors including smoking and physical inactivity in Korean office workers.

Physical activity and all-cause mortality in Korean older adults

Abstract Background: The association between physical activity (PA) and all-cause mortality may be modulated by potential confounders. Aim: To investigate the association between weekly PA and all-cause mortality in a population-based prospective study. Subjects and methods: The study sample included Korean older adults aged 60 years and older who participated in baseline assessments (n = 15 416) in 2008 and completed follow-up visits in 2011 (n = 14,976). Primary outcome was 3-year all-cause mortality. Results: Compared with sufficiently active individuals (with Hazard Ratio (HR) = 1), completely inactive and insufficiently active individuals had a significantly higher risk of all-cause mortality (HR = 2.086, 95% CI = 1.639–2.655, p < 0.00 and HR = 1.644, 95% CI = 1.013–2.668, p = 0.044, respectively), even after adjustments for age and sex, health-related behaviour factors (i.e. smoking, alcohol intake and nutritional risk), cognitive impairment and components of frailty phenotype (i.e. involuntary weight loss, exhaustion and slowness). In addition, the inverse association between PA and all-cause mortality is differently modulated by potential confounders, including age, sex, smoking, depressive symptoms, cognitive impairment and involuntary weight loss. Conclusion: PA was inversely and independently associated with all-cause mortality in Korean older adults.

Exercise Attenuates High-Fat Diet–induced Disease Progression in 3xTg-AD Mice

Purpose Little is known regarding the therapeutic role of exercise against the risk of a high-fat diet (HFD) for Alzheimers disease (AD) and AD-like cognitive deficits. This study aimed to investigate the therapeutic effect of treadmill running against HFD-induced progression in AD neuropathology and cognitive impairments in the triple-transgenic AD (3xTg-AD) mice. Methods The 3xTg-AD mice were assigned to a chow diet (control, n = 10), an HFD (n = 10), or an HFD combined with exercise (HFD + EX, n = 10) group. Mice in the HFD were fed with a 60% fat diet for 20 wk. The HFD + EX mice were additionally subjected to treadmill running. Results Compared with the control mice, the HFD mice had impaired brain insulin signaling, exacerbated AD neuropathology, defects in synaptic stability/plasticity, and apoptotic neuronal cell death in conjunction with exacerbated cognitive deficits in the affected brain regions, which were all significantly alleviated in the HFD + EX mice. Conclusion The current findings suggest that treadmill running protects against AD-like disease progression and cognitive deficits caused by an HFD in the 3xTg-AD mice.