Cholesterol absorption blocker ezetimibe prevents muscle wasting in severe dysferlin‐deficient and mdx mice

Background Muscular dystrophy (MD) causes muscle wasting and is often lethal in patients due to a lack of proven therapies. In contrast, mouse models of MD are notoriously mild. We have previously shown severe human‐like muscle pathology in mdx [Duchenne MD (DMD)] and dysferlin‐deficient limb‐girdle MD type 2B (LGMD2B) mice by inactivating the gene encoding for apolipoprotein E (ApoE), a lipid transporter synthesized by the liver, brain and adipocytes to regulate lipid and fat metabolism. Having recently established that human DMD is a novel type of primary genetic dyslipidaemia with elevated cholesterol, we sought to determine whether cholesterol could exacerbate the muscle wasting process observed in severe rodent MD. Methods Severe mdx and dysferlin knock‐out mice lacking ApoE were treated with ezetimibe (15 mg/kg/day), a clinically approved drug exhibiting few pleiotropic effects. In separate studies, dietary cholesterol was raised (from 0.2% to 2% cholesterol) in combination with experimental micro‐injury and direct cholesterol injection assays. Muscles were assessed histologically for changes in collagen and adipocyte infiltration and both transcriptomic and cellular changes by RNA‐seq and fluorescence‐activated cell sorting analysis. Results Treatment of severe DMD and LGMD2B mice with ezetimibe completely prevented clinical signs of ambulatory dysfunction (0% incidence vs. 33% for vehicle treatment; P