F Seebacher1, J Tallis2, K McShea1, R S James2. 1. School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia. 2. Centre for Applied Biological and Exercise Sciences, Coventry University, Coventry, UK.
Abstract
BACKGROUND/ OBJECTIVES: Obesity can affect muscle phenotypes, and may thereby constrain movement and energy expenditure. Weight loss is a common and intuitive intervention for obesity, but it is not known whether the effects of obesity on muscle function are reversible by weight loss. Here we tested whether obesity-induced changes in muscle metabolic and contractile phenotypes are reversible by weight loss. SUBJECTS/ METHODS: We used zebrafish (Danio rerio) in a factorial design to compare energy metabolism, locomotor capacity, muscle isometric force and work-loop power output, and myosin heavy chain (MHC) composition between lean fish, diet-induced obese fish, and fish that were obese and then returned to lean body mass following diet restriction. RESULTS: Obesity increased resting metabolic rates (P<0.001) and decreased maximal metabolic rates (P=0.030), but these changes were reversible by weight loss, and were not associated with changes in muscle citrate synthase activity. In contrast, obesity-induced decreases in locomotor performance (P=0.0034), and isolated muscle isometric stress (P=0.01), work-loop power output (P<0.001) and relaxation rates (P=0.012) were not reversed by weight loss. Similarly, obesity-induced decreases in concentrations of fast and slow MHCs, and a shift toward fast MHCs were not reversed by weight loss. CONCLUSION: Obesity-induced changes in locomotor performance and muscle contractile function were not reversible by weight loss. These results show that weight loss alone may not be a sufficient intervention.
BACKGROUND/ OBJECTIVES:Obesity can affect muscle phenotypes, and may thereby constrain movement and energy expenditure. Weight loss is a common and intuitive intervention for obesity, but it is not known whether the effects of obesity on muscle function are reversible by weight loss. Here we tested whether obesity-induced changes in muscle metabolic and contractile phenotypes are reversible by weight loss. SUBJECTS/ METHODS: We used zebrafish (Danio rerio) in a factorial design to compare energy metabolism, locomotor capacity, muscle isometric force and work-loop power output, and myosin heavy chain (MHC) composition between lean fish, diet-induced obese fish, and fish that were obese and then returned to lean body mass following diet restriction. RESULTS:Obesity increased resting metabolic rates (P<0.001) and decreased maximal metabolic rates (P=0.030), but these changes were reversible by weight loss, and were not associated with changes in muscle citrate synthase activity. In contrast, obesity-induced decreases in locomotor performance (P=0.0034), and isolated muscle isometric stress (P=0.01), work-loop power output (P<0.001) and relaxation rates (P=0.012) were not reversed by weight loss. Similarly, obesity-induced decreases in concentrations of fast and slow MHCs, and a shift toward fast MHCs were not reversed by weight loss. CONCLUSION:Obesity-induced changes in locomotor performance and muscle contractile function were not reversible by weight loss. These results show that weight loss alone may not be a sufficient intervention.
Authors: Huei-Fen Jheng; Shin-Han Huang; Hsueh-Maio Kuo; Michael W Hughes; Yau-Sheng Tsai Journal: Ann N Y Acad Sci Date: 2015-08-24 Impact factor: 5.691
Authors: Theodore Garland; Heidi Schutz; Mark A Chappell; Brooke K Keeney; Thomas H Meek; Lynn E Copes; Wendy Acosta; Clemens Drenowatz; Robert C Maciel; Gertjan van Dijk; Catherine M Kotz; Joey C Eisenmann Journal: J Exp Biol Date: 2011-01-15 Impact factor: 3.312
Authors: Maxwell S Denies; Jordan Johnson; Amanda B Maliphol; Michael Bruno; Annabelle Kim; Abbas Rizvi; Kevyn Rustici; Scott Medler Journal: Physiol Rep Date: 2014-01-28
Authors: Kelsey H Collins; Walter Herzog; Graham Z MacDonald; Raylene A Reimer; Jaqueline L Rios; Ian C Smith; Ronald F Zernicke; David A Hart Journal: Front Physiol Date: 2018-02-23 Impact factor: 4.566
Authors: Takuji Usui; Daniel W A Noble; Rose E O'Dea; Melissa L Fangmeier; Malgorzata Lagisz; Daniel Hesselson; Shinichi Nakagawa Journal: PeerJ Date: 2018-01-17 Impact factor: 2.984