Mitochondrial Uncoupling Reverses Sarcopenic Obesity while Enhancing Glucose Homeostasis and Muscle Function in Aged C57BL/6J Mice

Background: Sarcopenic obesity (SO) is associated with poorer physical performance in the elderly and will increase in relevance with population ageing and the obesity epidemic. The lack of a consensus definition for SO has resulted in variability in its reported prevalence, poor inter-definitional agreement, and disagreement on its impact on physical performance, impeding further development in the field. While sarcopenia definitions have been compared, the impact of obesity definitions in SO has been less well-studied. Objectives: To compare 3 widely-adopted definitions of obesity in terms of SO prevalence, inter-definitional agreement, and association with muscle function. Design: Cross-sectional. Setting: GERILABS study, Singapore Participants: 200 community-dwelling, functionally-independent older adults. Measurements: We utilized three commonly-used definitions of obesity: body mass index (BMI), waist circumference (WC) and DXA-derived fat mass percentage (FM%). Sarcopenia was defined using Asian Working Group for Sarcopenia criteria. For muscle function, we assessed handgrip strength, gait speed and Short Physical Performance Battery (SPPB). Subjects were classified into 4 body composition phenotypes (normal, obese, sarcopenic and SO), and outcomes were compared between groups. Results: The prevalence rate for SO was lowest for BMI (0.5%) compared to FM% (10.0%) and WC (10.5%). Inter-definitional agreement was lowest between BMI and WC (κ=0.364), and at best moderate between FM% and WC (κ=0.583). SO performed the worst amongst body composition phenotypes in handgrip strength, gait speed and SPPB (all p<0.01) only when defined using WC. In regression analyses, SO was associated with decreased SPPB scores (β=-0.261, p=0.001) only for the WC definition. Conclusion: There is large variation in the prevalence of SO across different obesity definitions, with low-to-moderate agreement between them. Our results corroborate recent evidence that WC, and thus central obesity, is best associated with poorer muscle function in SO. Thus, WC should be further explored in defining obesity for accurate and early characterization of SO among older adults in Asian populations.

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Abstract #862211: Muscle Mass and Muscle Function Determinants in Elderly Patients with Type 2 Diabetes: A Cross-Sectional Study

Endocrine Practice ◽

10.1016/s1530-891x(20)39867-0 ◽

2020 ◽

Vol 26 ◽

pp. 158-159

Author(s):

Bagher Larijani

Keyword(s):

Type 2 Diabetes ◽

Elderly Patients ◽

Muscle Mass ◽

Muscle Function ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional

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798 Sarcolemma depolarization eliminates mitochondrial uncoupling by an ATP-sensitive potassium channel opener, P-1075, in rat hearts

European Journal of Heart Failure Supplements ◽

10.1016/s1567-4215(03)90530-3 ◽

2003 ◽

Vol 2 (1) ◽

pp. 174

Author(s):

O JILKINA ◽

B KUZIO ◽

G GROVER ◽

V KUPRIYANOV

Keyword(s):

Potassium Channel ◽

Potassium Channel Opener ◽

Mitochondrial Uncoupling ◽

Channel Opener ◽

Rat Hearts

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Supplementation with beta-hydroxy-beta-methylbutyrate impacts glucose homeostasis and increases liver size in trained mice

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000445 ◽

2020 ◽

Vol 90 (1-2) ◽

pp. 113-123

Author(s):

Ines Schadock ◽

Barbara G. Freitas ◽

Irae L. Moreira ◽

Joao A. Rincon ◽

Marcio Nunes Correa ◽

...

Keyword(s):

Strength Training ◽

Muscle Mass ◽

Glucose Homeostasis ◽

Fasting Blood Glucose ◽

Hepatic Metabolism ◽

Mass Gain ◽

Trained Group ◽

Tissue Mass ◽

Liver Size ◽

Intensive Training

Abstract. β-hydroxy-β-methyl butyrate (HMB) is a bioactive metabolite derived from the amino acid leucine, usually applied for muscle mass increase during physical training, as well as for muscle mass maintenance in debilitating chronic diseases. The hypothesis of the present study is that HMB is a safe supplement for muscle mass gain by strength training. Based on this, the objective was to measure changes in body composition, glucose homeostasis and hepatic metabolism of HMB supplemented mice during strength training. Two of four groups of male mice (n = 6/group) underwent an 8-week training period session (climbing stairs) with or without HMB supplementation (190 mg/kgBW per day). We observed lower body mass gain (4.9 ± 0.43% versus 1.2 ± 0.43, p < 0.001) and increased liver mass (40.9 ± 0.9 mg/gBW versus 44.8 ± 1.3, p < 0.001) in the supplemented trained group compared with the non-supplemented groups. The supplemented trained group had an increase in relative adipose tissue mass (12.4 ± 0.63 mg/gBW versus 16.1 ± 0.88, P < 0.01) compared to the non-supplemented untrained group, and an increase in fasting blood glucose (111 ± 4.58 mg/dL versus 122 ± 3.70, P < 0.05) and insulin resistance (3.79 ± 0.19 % glucose decay/min versus 2.45 ± 0.28, P < 0.05) comparing with non-supplemented trained group. Adaptive heart hypertrophy was observed only in the non-supplemented trained group (4.82 ± 0.05 mg/gBW versus 5.12 ± 0.13, P < 0.05). There was a higher hepatic insulin-like growth factor-1 expression (P = 0.002) in supplemented untrained comparing with non-supplemented untrained group. Gene expression of gluconeogenesis regulatory factors was increased by training and reduced by HMB supplementation. These results confirm that HMB supplementation associated with intensive training protocol drives changes in glucose homeostasis and liver metabolism in mice.

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