Impact of physical training on resistance to insulin action, lipid content, angiogenesis and fibrogenesis of skeletal muscle in patients with idiopathic inflammatory myopathies

Abstract

Idiopathic inflammatory myopathies (MII) are rare systemic autoimmune diseases associated with high morbidity and functional disability. They can be classified as dermatomyositis (DM), polymyositis (PM), immune-mediated necrotizing myopathy (IMNM), inclusion body myositis (IBM), among others. Patients have primarilt skeletal muscle involvement, accompanied by decreased muscle strength, muscle function, quality of life and aerobic capacity. In addition, they present muscle atrophy/hypotrophy, associated with increased fibrogenesis and lipogenesis, and decreased angiogenesis and oxidative capacity of lipids in muscle tissues. Moreover, our group showed for the first time in the literature that patients with MII have a high prevalence of metabolic syndrome and a peripheral increase of insulin resistance (IR). Increased IR in skeletal muscle further impairs oxidation of lipids in this territory, culminating in the accumulation of this metabolite. In this context, physical training could improve and favor oxidative capacity and angiogenesis. On the other hand, it could attenuate IR, as well as the mechanism of lipogenesis and fibrogenesis in muscle tissues. Clinically, there would be improvement of aerobic capacity, muscle strength and function, quality of life, and decrease of morbimortality. (AU)