Mid Sweden University

Introduction: Skeletal muscle is changed after stroke, but conflicting data exist concerning muscle morphology and oxidative enzyme capacity. Methods: In 36 chronic stroke patients bilateral rectus femoris muscle biopsies were analyzed, and fiber type proportions and cross-sectional areas were determined by ATPase histochemistry. Enzymatic concentrations of citrate synthase (CS) and 3-Hydroxyacyl-coenzymeA-dehydrogenase (HAD) were determined using freeze-dried muscle tissue. Findings were correlated with clinical outcomes. Results: In the paretic muscles the mean fiber area was smaller (P=0.0004), and a lower proportion of type 1 fibers (P=0.0016) and a higher proportion of type 2X fibers (P=0.0002) were observed. The paretic muscle had lower CS (P=0.013) and HAD concentrations (P=0.037). Mean fiber area correlated with muscle strength (r=0.43; P=0.041), and CS concentration correlated with aerobic capacity (r=0.47; P=0.01). Conclusions: In stroke survivors there is a phenotypic shift toward more fatigable muscle fibers with reduced oxidative enzymatic capacity that relates to clinical outcomes. Muscle Nerve53: 748-754, 2016