Faculty Collaboration Database

Strength, skeletal muscle composition, and enzyme activity in multiple sclerosis. J Appl Physiol (1985) 1997 Dec;83(6):1998-2004

Date

02/14/1998

Pubmed ID

9390973

DOI

10.1152/jappl.1997.83.6.1998

Scopus ID

2-s2.0-0031457041 (requires institutional sign-in at Scopus site)   213 Citations

Abstract

This study examined functional, biochemical, and morphological characteristics of skeletal muscle in nine multiple sclerosis (MS) patients and eight healthy controls in an effort to ascertain whether intramuscular adaptations could account for excessive fatigue in this disease. Analyses of biopsies of the tibialis anterior muscle showed that there were fewer type I fibers (66 +/- 6 vs. 76 +/- 6%), and that fibers of all types were smaller (average downward arrow26%) and had lower succinic dehydrogenase (SDH; average downward arrow40%) and SDH/alpha-glycerol-phosphate dehydrogenase (GPDH) but not GPDH activities in MS vs. control subjects, suggesting that muscle in this disease is smaller and relies more on anaerobic than aerobic-oxidative energy supply than does muscle of healthy individuals. Maximal voluntary isometric force for dorsiflexion was associated with both average fiber cross-sectional area (r = 0.71, P = 0.005) and muscle fat-free cross-sectional area by magnetic resonance imaging (r = 0.80, P < 0. 001). Physical activity, assessed by accelerometer, was associated with average fiber SDH/GPDH (r = 0.78, P = 0.008). There was a tendency for symptomatic fatigue to be inversely associated with average fiber SDH activity (r = -0.57, P = 0.068). The results of this study suggest that the inherent characteristics of skeletal muscle fibers per se and of skeletal muscle as a whole are altered in the direction of disuse in MS. They also suggest that changes in skeletal muscle in MS may significantly affect function.

Author List

Kent-Braun JA, Ng AV, Castro M, Weiner MW, Gelinas D, Dudley GA, Miller RG

Author

Alexander V. Ng PhD Associate Professor in the Exercise Science department at Marquette University

MESH terms used to index this publication - Major topics in bold

Adult
Body Composition
Female
Glycerolphosphate Dehydrogenase
Humans
Isometric Contraction
Magnetic Resonance Imaging
Male
Middle Aged
Multiple Sclerosis
Muscle, Skeletal
Nerve Fibers
Succinate Dehydrogenase