Structural changes in skeletal muscles of Ossabaw miniature swine with metabolic syndrome

Abstract

Ossabaw swine fed excess kcal and atherogenic diets develop metabolic syndrome (MetS) characterized by obesity, dyslipidemia, hypertension, insulin resistance, and glucose intolerance. The purpose of this study was to test the hypothesis that MetS could have a detrimental effect on skeletal muscle structure and function. Adult Ossabaw swine were fed Control (C), high fructose (F) or high fat/cholesterol/fructose (H) diets for 28 weeks. Biceps femoris and plantaris muscles were analyzed. F swine showed mild MetS, lacking increase in LDL and total cholesterol, both of which were highly up‐regulated in H swine. There were no significant differences in cross sectional areas of muscle fibers of swine on C and F diets. Ossabaw swine fed H diet showed a 20% decrease in size of Type 2B fibers in biceps femoris muscles and a 30% increase in plantaris muscles. Physiological differences between these two muscles might explain these disparate findings. H diet caused increased accumulation of intramyocellular lipid droplets. This finding correlates well with a 5‐fold increase in total plasma cholesterol of H fed Ossabaw swine and suggests a role of dyslipidemia in structural defects in MetS. Support: NIH HL013223 (MS), HL062552 (MS) and IUSM‐Northwest (TK).