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- Title
Calorie Restriction-induced Weight Loss and Exercise Have Differential Effects on Skeletal Muscle Mitochondria Despite Similar Effects on Insulin Sensitivity.
- Authors
Menshikova, Elizaveta V.; Ritov, Vladimir B.; Dube, John J.; Amati, Francesca; Stefanovic-Racic, Maja; Toledo, Frederico G. S.; Coen, Paul M.; Goodpaster, Bret H.
- Abstract
<bold>Background: </bold>Skeletal muscle insulin resistance and reduced mitochondrial capacity have both been reported to be affected by aging. The purpose of this study was to compare the effects of calorie restriction-induced weight loss and exercise on insulin resistance, skeletal muscle mitochondrial content, and mitochondrial enzyme activities in older overweight to obese individuals.<bold>Methods: </bold>Insulin-stimulated rates of glucose disposal (Rd) were determined using the hyperinsulinemic euglycemic clamp before and after completing 16 weeks of either calorie restriction to induce weight loss (N = 7) or moderate exercise (N = 10). Mitochondrial volume density, mitochondria membrane content (cardiolipin), and activities of electron transport chain (rotenone-sensitive NADH-oxidase), tricarboxylic acid (TCA) cycle (citrate synthase) and β-oxidation pathway (β-hydroxyacyl CoA dehydrogenase; β-HAD) were measured in percutaneous biopsies of the vastus lateralis before and after the interventions.<bold>Results: </bold>Rd improved similarly (18.2% ± 9.0%, p < .04) with both weight loss and exercise. Moderate exercise significantly increased mitochondrial volume density (14.5% ± 2.0%, p < .05), cardiolipin content (22.5% ± 13.4%, p < .05), rotenone-sensitive NADH-oxidase (65.7% ± 13.2%, p = .02) and β-HAD (30.7% ± 6.8%, p ≤ .03) activity, but not citrate synthase activity (10.1% ± 4.0%). In contrast, calorie restriction-induced weight loss did not affect mitochondrial content, NADH-oxidase or β-HAD, yet increased citrate synthase activity (44.1% ± 21.1%, p ≤ .04). Exercise (increase) or weight loss (decrease) induced a remodeling of cardiolipin with a small (2%-3%), but significant change in the relative content of tetralinoleoyl cardiolipin.<bold>Conclusion: </bold>Exercise increases both mitochondria content and mitochondrial electron transport chain and fatty acid oxidation enzyme activities within skeletal muscle, while calorie restriction-induced weight loss did not, despite similar improvements in insulin sensitivity in overweight older adults.
- Subjects
LOW-calorie diet; EXERCISE physiology; MUSCLE metabolism; OBESITY; WEIGHT loss; SKELETAL muscle physiology; PHYSIOLOGY; REDUCING diets; DNA metabolism; DIET therapy; EXERCISE; INSULIN; INSULIN resistance; MITOCHONDRIA; SKELETAL muscle; GLUCOSE clamp technique
- Publication
Journals of Gerontology Series A: Biological Sciences & Medical Sciences, 2018, Vol 73, Issue 1, p81
- ISSN
1079-5006
- Publication type
journal article
- DOI
10.1093/gerona/glw328