Skeletal muscle of females and males with constitutional thinness: a low intramuscular lipid content and oxidative profile
Year: 2020
Type: article
Abstract: Constitutional thinness (CT) is a nonpathological state of underweight. The current study aimed to explore skeletal muscle energy storage in individuals with CT and to further characterize muscle phenotype at baseline and in response to overfeeding. Thirty subjects with CT (15 females, 15 males) and 31 normal-weight control subjects (16 females, 15 males) participated in the study. Histological and enzymological analyses were performed on muscle biopsy specimens before and after overfeeding. In the skeletal muscle of CT participants compared with controls, we observed a lower content of intramuscular triglycerides for type I (−17%, p < 0.01) and type IIA (−14%, p < 0.05) muscle fibers, a lower glycogen content for type I (−6%, p < 0.01) and type IIA (−5%, p < 0.05) muscle fibers, a specific fiber-type distribution, a marked muscle hypotrophy (−20%, p < 0.001), a low capillary-to-fiber ratio (−19%, p < 0.001), and low citrate synthase activity (−18%, p < 0.05). In response to overfeeding, CT participants increased their intramuscular triglycerides content in type I (+10%, p < 0.01) and type IIA (+9%, p < 0.01) muscle fibers. CT individuals seem to present an unusual muscle phenotype and different adaptations to overfeeding compared with normal-weight individuals, suggesting a specific energy metabolism and muscle adaptations. ClinicalTrials.gov registration no. NCT02004821. Novelty Low intramuscular triglycerides and glycogen content in skeletal muscle of constitutionally thin individuals. Low oxidative capacity, low capillary supply, and fiber hypotrophy in skeletal muscle of constitutionally thin individuals. Increase in intramuscular triglycerides in constitutional thinness in response to overfeeding.
Institutions: Université Clermont Auvergne, Centre de Recherche en Nutrition Humaine d'Auvergne, Troubles du comportement Alimentaire, Addictions et Poids Extrêmes, Adaptations Métaboliques à l'Exercice en conditions Physiologiques et Pathologiques, Université Jean Monnet, Centre Hospitalier Universitaire de Saint-Étienne, Laboratoire Interuniversitaire de Biologie de la Motricité, Centre Hospitalier Universitaire de Clermont-Ferrand, Université Savoie Mont Blanc, Inserm, École Polytechnique Fédérale de Lausanne
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3030739730