Exercise training attenuates pulmonary inflammation and mitochondrial dysfunction in a mouse model of high-fat high-carbohydrate-induced NAFLD.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) can lead to pulmonary dysfunction that is associated with pulmonary inflammation. Moreover, little is known regarding the therapeutic role of exercise training on pulmonary pathophysiology in NAFLD. The present study aimed to investigate the effect of exercise training on high-fat high-carbohydrate (HFHC)-induced pulmonary dysfunction in C57BL/6 mice. METHODS: Male C57BL/6 mice (N = 40) were fed a standard Chow (n = 20) or an HFHC (n = 20) diet for 15 weeks. After 8 weeks of dietary treatment, they were further assigned to 4 subgroups for the remaining 7 weeks: Chow (n = 10), Chow plus exercise (Chow+EX, n = 10), HFHC (n = 10), or HFHC plus exercise (HFHC+EX, n = 10). Both Chow+EX and HFHC+EX mice were subjected to treadmill running. RESULTS: Chronic exposure to the HFHC diet resulted in obesity with hepatic steatosis, impaired glucose tolerance, and elevated liver enzymes. The HFHC significantly increased fibrotic area (p < 0.001), increased the mRNA expression of TNF-α (4.1-fold, p < 0.001), IL-1ß (5.0-fold, p < 0.001), col1a1 (8.1-fold, p < 0.001), and Timp1 (6.0-fold, p < 0.001) in the lung tissue. In addition, the HFHC significantly altered mitochondrial function (p < 0.05) along with decreased Mfn1 protein levels (1.8-fold, p < 0.01) and increased Fis1 protein levels (1.9-fold, p < 0.001). However, aerobic exercise training significantly attenuated these pathophysiologies in the lungs in terms of ameliorating inflammatory and fibrogenic effects by enhancing mitochondrial function in lung tissue (p < 0.001). CONCLUSIONS: The current findings suggest that exercise training has a beneficial effect against pulmonary abnormalities in HFHC-induced NAFLD through improved mitochondrial function.

Moderate aerobic exercise training ameliorates impairment of mitochondrial function and dynamics in skeletal muscle of high-fat diet-induced obese mice.

The purpose of this study is to determine whether moderate aerobic exercise training improves high-fat diet-induced alterations in mitochondrial function and structure in the skeletal muscle. Male 4-week-old C57BL/6 mice were randomly divided into four groups: control (CON), control plus exercise (CON + EX), high-fat diet (HFD), and high-fat diet plus exercise (HFD + EX). After obesity was induced by 20 weeks of 60% HFD, treadmill exercise training was performed at 13-16 m/min, 40-50 min/day, and 6 days/week for 12 weeks. Mitochondrial structure, function, and dynamics, and mitophagy were analyzed in the skeletal muscle fibers from the red gastrocnemius. Exercise training increased mitochondrial number and area and reduced high-fat diet-induced obesity and hyperglycemia. In addition, exercise training attenuated mitochondrial dysfunction in the permeabilized myofibers, indicating that HFD-induced decrease of mitochondrial O2 respiration and Ca2+ retention capacity and increase of mitochondrial H2 O2 emission were attenuated in the HFD + EX group compared to the HFD group. Exercise also ameliorated HFD-induced imbalance of mitochondrial fusion and fission, demonstrating that HFD-induced decrease in fusion protein levels was elevated, and increase in fission protein levels was reduced in the HFD + EX groups compared with the HFD group. Moreover, dysregulation of mitophagy induced by HFD was mitigated in the HFD + EX group, indicating a decrease in PINK1 protein level. Our findings demonstrated that moderate aerobic exercise training mitigated obesity-induced insulin resistance by improving mitochondrial function, and reversed obesity-induced mitochondrial structural damage by improving mitochondrial dynamics and mitophagy, suggesting that moderate aerobic exercise training may play a therapeutic role in protecting the skeletal muscle against mitochondrial impairments and insulin resistance induced by obesity.

Re-Setting the Circadian Clock Using Exercise against Sarcopenia.

Sarcopenia is defined as the involuntary loss of skeletal muscle mass and function with aging and is associated with several adverse health outcomes. Recently, the disruption of regular circadian rhythms, due to shift work or nocturnal lifestyle, is emerging as a novel deleterious factor for the development of sarcopenia. The underlying mechanisms responsible for circadian disruption-induced sarcopenia include molecular circadian clock and mitochondrial function associated with the regulation of circadian rhythms. Exercise is a potent modulator of skeletal muscle metabolism and is considered to be a crucial preventative and therapeutic intervention strategy for sarcopenia. Moreover, emerging evidence shows that exercise, acting as a zeitgeber (time cue) of the skeletal muscle clock, can be an efficacious tool for re-setting the clock in sarcopenia. In this review, we provide the evidence of the impact of circadian disruption on skeletal muscle loss resulting in sarcopenia. Furthermore, we highlight the importance of exercise timing (i.e., scheduled physical activity) as a novel therapeutic strategy to target circadian disruption in skeletal muscle.

Handgrip strength, depression, and all-cause mortality in Korean older adults.

BACKGROUND: Decreased muscle strength and/or depression with aging are emerging as important public health concerns in both developed and developing countries. This study investigated the effects of low handgrip strength (HGS) and depression on the risk of all-cause mortality in Korean older adults. METHODS: Data from 13,901 Korean adults (57% women) who participated in the 2008 baseline survey and completed the 2011 follow-up assessments were used. RESULTS: In total, the current findings showed that individuals with depression only and individuals with low HGS plus depression had significantly higher risks of all-cause mortality (hazard ratio (HR) = 1.366, 95% confidence interval (CI) = 1.033-1.807, p = 0.029 and HR = 1.961, 95% CI = 1.409-2.736, p < 0.001, respectively) even after adjustments for all the measured covariates, compared with individuals with high HGS plus no depression (HR = 1). Gender-stratified analysis showed that men with depression only and men with depression plus low HGS had significantly higher risks of all-cause mortality (HR = 1.376, 95% CI =1.029-1.841, p = 0.031 and HR = 1.861, 95% CI = 1.306-2.651, p = 0.001, respectively) even after adjustments for all the measured covariates, compared with individuals with no depression plus high HGS (HR = 1). In women, however, the joint effect of depression and low HGS only remained significant at borderline (HR = 2.603, 95% CI = 0.981-6.908, p = 0.055) when adjusted for all the confounders. CONCLUSION: The current finding suggested that depression and low HGS were significantly and synergistically associated with the increased risk of premature death from all causes in the Korean geriatric population.

Weight Status, Physical Activity, and Depression in Korean Older Adults.

BACKGROUND: This study aimed to explore the associations between weight status, physical activity, and depression in Korean older adults. METHODS: We used the baseline data drawn from the 2008 baseline survey utilized in the Living Profiles of Older People Survey, comprised of 15,146 community-dwelling older people (42.6% men and 57.4% women) aged 60 years and older residing in the Republic of Korea. After excluding respondents with missing data on height, weight, and physical activity (PA), data on 10,197 samples (43.3% men and 56.7% women) were analyzed in this study. RESULTS: Underweight and completely inactive individuals had poorer sociodemographic and health behavioral characteristics and increased risks of late-life depression compared with normal weight and sufficiently active individuals, respectively. In terms of the aerobic PA guidelines, completely inactive individuals had a significantly higher risk of late-life depression (odds ratio 1.730; 95% confidence interval, 1.412-2.120) compared with sufficiently active individuals, even after adjustments for age, education, household income, night sleeping, living status, marital status, smoking, number of comorbidities, nutritional status, self-reported health status, and cognitive performance as covariates. In addition, those who did not meet the PA guidelines and were underweight or overweight/obese were more likely to have late-life depression compared to those who were active and normal weight. CONCLUSIONS: The current findings of the study suggest that modifiable, lifestyle risk factors, such as physical inactivity, underweight, and overweight/obesity, are positively associated with late-life depression in Korean older adults.

Physical activity and all-cause mortality in Korean older adults.

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.

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

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.

Body Fat and Physical Activity Modulate the Association Between Sarcopenia and Osteoporosis in Elderly Korean Women.

This study examined whether modifiable lifestyle factors, such as body fatness and physical activity, modulate the association between sarcopenia and osteoporosis. In a cross-sectional design, 269 postmenopausal women, aged 65 years and older, underwent dual-energy X-ray absorptiometry (DEXA) scans to measure their body fat percentage, total fat mass, total fat-free mass, appendicular lean mass, bone mineral density (BMD) and bone mineral content. The participants wore a uniaxial accelerometer for seven consecutive days to quantify daily physical activity. The collected data were analyzed using descriptive statistics, Pearson correlation, and a binary logistic regression. Pearson correlation analyses showed that total neck/femur BMD was positively associated with weight-adjusted appendicular skeletal muscle mass (ASM) and objectively-measured physical activities. ASM was positively associated with body fatness. Binary logistic regression analyses showed that the odds ratio (OR) of sarcopenia for osteopenia and/or osteoporosis was substantially attenuated but remained marginally significant when adjusted for age and postmenopausal period (OR = 2.370 and p = 0.050). However, the OR was no longer significant when additionally adjusted for body fatness (OR = 2.218 and p = 0.117) and physical activity (OR = 1.240 and p = 0.448). The findings of the study showed that, in this sample of elderly Korean women, modifiable lifestyle risk factors such as body fatness and physical inactivity played an important role in determining the association between sarcopenia and osteopenia/osteoporosis.

Impact of Exercise Training on Survival Rate and Neural Cell Death in Sepsis Through the Maintenance of Redox Equilibrium.

PURPOSE: Sepsis-related deaths occur during both the early proinflammatory and the late immunosuppressive phases of the condition. The balance of pro- and anti-inflammatory responses is influenced by damaged cells that die via either proinflammatory necroptosis or anti-inflammatory apoptosis. Both forms of cell death may be mediated by reactive oxygen species (ROS) generated during the proinflammatory response. Recent evidence suggests that exercise training boosts antioxidative capacity and could offer protection against sepsis. Given these findings, we aimed to examine the impact of exercise training on neural cell death in the context of sepsis. METHODS: We assessed the effectiveness of exercise in reducing ROS production and the inflammatory response using a cecal ligation and puncture (CLP)-induced sepsis model. Forty C57BL/6N male mice were randomly divided into 2 groups: control (CLP-Con; n=20) and experimental (CLP-Ex; n=20). Before the induction of sepsis by CLP, the CLP-Ex mice underwent interval training on a treadmill 3 days per week for 8 weeks. Each day involved 10 cycles of 2 minutes at 8 m/min and 2 minutes at 15 m/min. After the CLP procedure, we monitored the survival of 10 mice from each group over a 30-hour period. RESULTS: The findings indicated that exercise training increased the survival rate among mice with CLP-induced sepsis by enhancing antioxidative capacity and delaying the transition from a hyperdynamic to an immunosuppressive state. CONCLUSION: Exercise training may delay the progression from the hyperdynamic state to the hypodynamic phase of sepsis by increasing antioxidant capacity and reducing apoptotic cell death.

Alterations in pulmonary vasomotor modulators post aerobic exercise training in non-alcoholic fatty liver disease.

This study investigated the impact of exercise training on major pulmonary vasomotor mediators and receptors including endothelial nitric oxide synthase (eNOS) inducible NOS (iNOS), endothelin-1 (ET-1), ET-1 receptors A (ETA) and-B (ETB) in high-fat-high-carbohydrate (HFHC) induced non-alcoholic fatty liver disease (NAFLD). NAFLD increased iNOS, ET-1 and ETA (p < 0.05), but not ETB (p > 0.05). Exercise attenuated iNOS, ET-1 and ETA (p < 0.05)., but not ETB (p > 0.05) and eNOS (p > 0.05). Exercise training is beneficial for pulmonary vasculature in NAFLD.

Position Statement: Exercise Guidelines for Osteoporosis Management and Fall Prevention in Osteoporosis Patients.

BACKGROUND: The effectiveness of exercise for improving osteoporosis and fall prevention in patients diagnosed with osteoporosis or osteopenia has not been fully summarized. The Korean Society for Bone and Mineral Research and the Korean Society of Exercise Physiology has developed exercise guidelines for patients with osteoporosis or osteopenia and provide evidence-based recommendations. METHODS: A systematic review identified randomized controlled trials (RCT) assessing the effect of resistance, impact, balance, aerobic training, and physical activity in osteoporosis and osteopenia on bone quality, physical performance, quality of life, and fall prevention. PubMed, Embase, KoreaMed, and RISS were searched from January 2000 to August 2022. Ten key questions were established to review the evidence and formulate recommendations. RESULTS: The 50 RCTs reported that even with osteoporosis and osteopenia, resistance and impact training consistently maximized bone strength, improved body strength and balance, and eventually reduced fall incidences. Resistance exercise combining 3 to 10 types of free weight and mechanical exercise of major muscle groups performed with an intensity of 50% to 85% 1-repetition maximum, 5 to 12 repetitions/set, 2 to 3 days/week, for 3 to 12 months is recommended. Impact exercises such as jumping chin-ups with drop landings and jump rope performed 50 jumps/session for at least 6 months with 3 or more days/week are recommended. CONCLUSIONS: A multi-component exercise mainly comprised of resistance and impact exercise seems to be an effective strategy to attenuate the risk factors of osteoporosis and osteopenia. The integration of exercise guidelines and individualized exercise plans has significant potential to reduce the morbidity and mortality of osteoporosis.

Genetic effects of adiponectin single nucleotide polymorphisms on the clustering of metabolic risk factors in young Korean adults.

Little is known if lifestyle-related risk factors modulate the adiponectin genetic effects on its outcome phenotypes. The aims of the study were to investigate whether the association between the adiponectin gene two SNPs (+45T>G, rs2241766 and +276G>T, rs1501299) and a clustering of metabolic risk factors is modified by both cardiorespiratory fitness (CRF) and insulin resistance in a study sample of 1,622 young Korean adults (941 men and 681 women, mean age 22.9 ± 2.4 years). The clustering of metabolic risk factors was defined as a sum of Z scores for waist circumference (WC), blood pressure (BP), triacylglycerols (TAG), high-density lipoprotein cholesterol, and fasting glucose. With respect to SNP +45T>G, the TT genotype had significantly higher values for BMI, WC, systolic BP, TAG, insulin, and a clustered risk score than did the TG+GG genotype. The genetic effect of SNP +45 on the clustered risk score remained significant even after controlling for age, sex, and smoking (P = 0.019). However, the genetic impact was no longer significant when additionally controlling for CRF (P = 0.097) and fasting insulin (P = 0.181), respectively. With respect to SNP +276G>T, the GT+TT genotypes had significantly higher values for BMI and TAG than did the TT genotype. In summary, the present findings suggest that the SNPs at position +45 and +276 are associated with several of metabolic risk factors; however, the genetic effect of SNP +45T/G variant on the clustered risk score is modulated by both CRF and insulin resistance.

Greater Muscular Strength Is Associated with a Lower Risk of Pulmonary Dysfunction in Individuals with Non-Alcoholic Fatty Liver Disease.

This study investigated the combined effect of handgrip strength (HGS) and non-alcoholic fatty liver disease (NAFLD) on pulmonary function using the Korea National Health and Nutrition Examination Survey (KNHANES) from 2016 to 2018. For the present study, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), the FEV1/FVC ratio, handgrip strength (HGS) and the hepatic steatosis index (HSI) to estimate NAFLD were obtained from nationwide cross-sectional surveys. For HGS, subjects were divided into higher HGS (upper 50%) and lower HGS (lower 50%). For NAFLD, subjects were divided into the NAFLD cohort (HSI > 36) and the normal cohort (HSI ≤ 36). Of 1651 subjects (men, n = 601), 25.5% of subjects (n = 421) met the HSI > 36. Based on the normal cohort with high HGS, the normal cohort with low HGS showed an increased risk of reduced FVC (OR = 3.062, 95% CI = 2.46−4.83, p < 0.001) and the NAFLD cohort with low HGS showed a further increased risk of reduced FVC (OR = 4.489, 95% CI = 3.43−7.09, p < 0.001). However, the risk of reduced FVC was not significantly increased in NAFLD with high HGS (OR = 1.297, 95% CI = 0.67−2.50, p = 0.436). After adjusted for covariates such as age, sex, smoking, FBG, HDL-C, TG, SBP, DBP, CRP and alcohol consumption, the results remained similar. More importantly, these results were consistent in the obesity-stratified analysis. The current findings of the study suggest that higher muscle strength is associated with a lower risk of reduced pulmonary function in individuals with NAFLD.

Moderate-Intensity Exercise Preserves Bone Mineral Density and Improves Femoral Trabecular Bone Microarchitecture in Middle-Aged Mice.

BACKGROUND: Aging leads to significant bone loss and elevated osteoporosis risk. Exercise slows age-related bone loss; however, the effects of various moderate-intensity exercise training volumes on bone metabolism remain unclear. This study aimed to determine the degree to which different volumes of moderate-intensity aerobic exercise training influence bone mineral density (BMD), bone mineral content (BMC), femoral trabecular bone microarchitecture, and cortical bone in middle-aged mice. METHODS: Twenty middle-aged male C57BL/6 mice were randomly assigned 8 weeks of either (1) non-exercise (CON); (2) moderate-intensity with high-volume exercise (EX_MHV); or (3) moderate-intensity with low-volume exercise (EX_MLV) (N=6-7, respectively). Femoral BMD and BMC were evaluated using dual energy X-ray absorptiometry, and trabecular and cortical bone were measured using micro-computed tomography. RESULTS: Femoral BMD in EX_MHV but not EX_MLV was significantly higher (P<0.05) than in CON. The distal femoral fractional trabecular bone volume/tissue volume (BV/TV, %) was significantly higher (P<0.05) in both EX_MHV and EX_MLV than in CON mice. Increased BV/TV was induced by significantly increased trabecular thickness (mm) and tended to be higher (P<0.10) in BV (mm3) and lower in trabecular separation (mm) in EX_MHV and EX_MLV than in CON. The femoral mid-diaphysis cortical bone was stronger in EX_MLV than EX_MHV. CONCLUSIONS: Long-term moderate-intensity aerobic exercise with low to high volumes can be thought to have a positive effect on hindlimb BMD and attenuate age-associated trabecular bone loss in the femur. Moderate-intensity aerobic exercise may be an effective and applicable exercise regimen to prevent age-related loss of BMD and BV.

Dynapenic-abdominal obesity as an independent risk factor for chronic kidney disease in postmenopausal women: a population-based cohort study.

OBJECTIVE: Low muscle strength and obesity lead to a higher risk of chronic kidney disease (CKD). Perimenopause is associated with a natural decline in muscle strength and an increase in visceral adiposity. Dynapenic obesity, which is the coexistence of low muscle strength and obesity, is expected to synergistically increase the prevalence of CKD in postmenopausal women. The aim of this study was to determine combined associations of dynapenia and obesity with CKD in postmenopausal women. METHODS: This study used data from the Korean National Health and Nutrition Examination Survey, 2016 to 2019. The study included 4,525 postmenopausal women aged 42 to 80 years that were classified into four groups based on waist circumference (≥85 cm) and hand grip strength (<18 kg): normal, dynapenic, obese, or dynapenic-obese. According to the Kidney Disease: Improving Global Outcomes, we defined CKD as an estimated glomerular filtration rate <60 mL/min per 1.73 m2. Complex sample logistic regression models were conducted to determine the relationships among coexistence of dynapenia, abdominal obesity, and the risk of CKD. RESULTS: Dynapenic-abdominal obese group displayed lower estimated glomerular filtration rate levels than other groups (P < 0.05 for all data). The prevalence rates of CKD were 15.5%, 7.8%, 6.2%, and 2.4% in the dynapenic-abdominal obese, dynapenic, abdominal obese, and normal groups, respectively (P < 0.001). Complex sample logistic regression analyses, after adjusting for age, height, health behaviors, and comorbidities, showed that the odds ratio for CKD with respect to dynapenic-abdominal obesity was 1.82 (95% confidence interval, 1.19-2.79) and to abdominal obesity was 1.54 (95% confidence interval, 1.07-2.22) than in the normal group. CONCLUSIONS: This study demonstrated that dynapenic-abdominal obesity, as determined by low handgrip strength and high waist circumference values, was associated with increased risk of CKD in postmenopausal women.

Clustering of metabolic syndrome risk factors associated with lifestyle factors and serum leptin in Korean children.

The present study investigated the relationships among metabolic risk factors, major lifestyle factors, and serum cytokines in a sample of Korean children. In a cross-sectional design, we studied a total of 275 children (130 boys and 145 girls) aged 12-13 years. Measured variables included anthropometrics, blood pressures (BP), VO2max, physical activity (PA), dietary intakes, lipids, glucose, and insulin. We explored the extent to which dietary intakes, VO2max, PA, and serum cytokines explained variance in a clustered risk score, which is a sum of Z scores for waist circumference, BP, TG, HDLC, and HOMA-IR, using a stepwise linear regression by blocks. VO2max, vigorous PA (VPA), and leptin were independent predictors for the clustered risk score while adjusting for age and Tanner stage. Our findings suggest that the clustered risk score is associated not only with low levels of VO2max and VPA, but also with elevated serum leptin in Korean children.

Trabecular Bone Microarchitecture Improvement Is Associated With Skeletal Nerve Increase Following Aerobic Exercise Training in Middle-Aged Mice.

Advancing age is associated with bone loss and an increased risk of osteoporosis. Exercise training improves bone metabolism and peripheral nerve regeneration, and may play a critical role in osteogenesis and increase in skeletal nerve fiber density. In this study, the potential positive role of aerobic exercise training in bone metabolism and skeletal nerve regeneration was comprehensively evaluated in 14-month-old male C57BL/6 mice. The mice were divided into two groups: no exercise (non-exercise group) and 8-weeks of aerobic exercise training (exercise group), with six mice in each group. Dual-energy X-ray absorptiometry and micro-computed tomography showed that femoral and tibial bone parameters improved after aerobic exercise training. Greater skeletal nerve fiber density was also observed in the distal femoral and proximal tibial periostea, measured and analyzed by immunofluorescence staining and confocal microscopy. Pearson correlation analysis revealed a significant association between skeletal nerve densities and trabecular bone volume/total volume ratios (distal femur; R 2 = 0.82, p < 0.05, proximal tibia; R 2 = 0.59, p = 0.07) in the exercise group; while in the non-exercise group no significant correlation was found (distal femur; R 2 = 0.10, p = 0.54, proximal tibia; R 2 = 0.12, p = 0.51). Analysis of archival microarray database confirmed that aerobic exercise training changed the microRNA profiles in the mice femora. The differentially expressed microRNAs reinforce the role of aerobic exercise training in the osteogenic and neurogenic potential of femora and tibiae. In conclusion, 8-weeks of aerobic exercise training positively regulate bone metabolism, an effect that paralleled a significant increase in skeletal nerve fiber density. These findings suggest that aerobic exercise training may have dual utility, both as a direct stimulator of bone remodeling and a positive regulator of skeletal nerve regeneration.

Relationships between Socioeconomic Status, Handgrip Strength, and Non-Alcoholic Fatty Liver Disease in Middle-Aged Adults.

Although low socioeconomic status (SES) and decreased muscle strength have been found to be associated with the risk factors of non-alcoholic fatty liver disease (NAFLD), including insulin resistance, obesity, and metabolic syndrome, the associations among SES, muscle strength, and NAFLD are still unclear. We aimed to investigate the combined effect of SES and relative handgrip strength (HGS) on the risk of NAFLD in middle-aged adults. Data from 5272 middle-aged adults who participated in the Korea National Health and Nutrition Examination Surveys (KNHANES) from 2014-2018 were analyzed. NAFLD was defined using the hepatic steatosis index (HSI) > 36 and the comprehensive NAFLD score (CNS) ≥ 40 in the absence of other causes of liver disease. SES was based on a self-reported questionnaire. Overall, individuals with low SES (odds ratio (OR) = 1.703, 95% confidence interval (CI): 1.424-2.037, p < 0.001) or low HGS (OR = 12.161, 95% CI: 9.548-15.488, p < 0.001) had a significantly higher risk of NAFLD. The joint association analysis showed that a low SES combined with a low HGS (OR = 2.479, 95% CI: 1.351-4.549, p = 0.003) further significantly increased the risk of NAFLD when adjusted for all the covariates, compared with individuals with a high SES and a high HGS (OR = 1). The current findings suggest that both low SES and low HGS were independently and synergistically associated with an increased risk of NAFLD in middle-aged Korean adults.

Exercise Training Attenuates Ovariectomy-Induced Alterations in Skeletal Muscle Remodeling, Apoptotic Signaling, and Atrophy Signaling in Rat Skeletal Muscle.

PURPOSE: The effects of aerobic exercise training on soleus muscle morphology, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in ovariectomized rat skeletal muscle were investigated. METHODS: Female Sprague-Dawley rats were divided into control (CON), ovariectomy (OVX), and ovariectomy plus exercise (OVX+EX) groups. After ovarian excision, exercise training was performed using a rat treadmill at 20 m/min, 50 min/day, 5 days/week for 12 weeks. Protein levels of mitochondria-mediated apoptotic signaling and atrophy/hypertrophy signaling in the skeletal muscle (soleus) were examined through western immunoblot analysis. RESULTS: The number of myocytes and myocyte cross-sectional area (CSA) were increased and the extramyocyte space was decreased in the OVX group compared to those in the CON group. However, aerobic exercise training significantly increased myocyte CSA and decreased extramyocyte space in the OVX+EX group compared to those in the OVX group. The protein levels of proapoptotic signaling and muscle atrophy signaling were significantly increased, whereas the protein levels of muscle hypertrophy signaling were significantly decreased in the OVX group compared to that in the CON group. Aerobic exercise training significantly decreased the protein levels of proapoptotic signaling and increased the protein level of antiapoptotic protein in the OVX+EX group compared to that in the OVX group. Aerobic exercise training significantly increased the protein levels of hypertrophy signaling and decreased protein levels of atrophy signaling in the OVX+EX group compared to those in the OVX group. CONCLUSION: Treadmill exercise improved estrogen deficiency-induced impairment in skeletal muscle remodeling, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in skeletal muscle.

Combined effects of body mass index and cardio/respiratory fitness on serum vaspin concentrations in Korean young men.

Little information is available regarding how body fatness and cardio/respiratory fitness (CRF) are associated with serum vaspin. The purpose of the study was to investigate the combined effect of body mass index (BMI) and CRF on serum vaspin in Korean young men. In a cross-sectional study, we examined 490 Korean young men (mean age 23.8 +/- 2.5 years) who were voluntarily recruited. Body fatness and fasting levels of serum insulin, adiponectin, and vaspin were measured. CRF was quantified as the minute volume of oxygen consumption (VO(2)) measured during a graded treadmill test. We assigned individuals to either low or middle or high third CRF tertiles based on age-adjusted VO(2max). We also assigned individuals to either a lean weight (LN) or obese (OB) group based on body fatness levels, in which a BMI value >/=25 kg/m(2) was used as an indicator of Pacific-Asian obesity. Group analyses showed significant interaction effects between fatness and CRF on fasting insulin and serum vaspin such that the OB group with low CRF levels had significantly higher insulin and vaspin concentrations than the OB counterparts with moderate to high CRF levels, and no such CRF-based sub-group differences in insulin and vaspin were found in the LN groups. Regression analyses show that BMI, waist circumference, VO(2), and fasting insulin explain approximately 18% of the individual variations in serum vaspin concentration in this study population. This is the first study to show that high body fatness along with low CRF might contribute to increased vaspin concentrations in Korean young men.