Levels of leptin, insulin, IGF-I, IGFBP-3, IL-6 and IL-8 in sera of patients with muscular dystrophy and mitochondrial encephalomyopathy

There is evidence that muscle forms part of endocrine networks, secreting/or responding to circulating agents such as leptin and interleukin-6 as well as the classical hormone insulin. To gain further insight into the possible role of these hormones and cytokines in muscle degenerative diseases, we investigate their concentrations in sera from patients with muscular dystrophy and mitochondrial encephalomyopathy. In 13 patients with muscular dystrophy, in eight patients with mitochondrial encephalomyopathy, and in 8 age-matched healthy control subjects, the concentrations of leptin, insulin, insulin-like growth factor I, insulin-like growth factor binding protein-3 (IGFBP-3), interleukin 6 and interleukin 8 in sera were determined. The only statistically significant difference between patient groups and controls was lower IGFBP-3 levels in patients with mitochondrial encephalomyopathy. Save the IGFBP-3, the other hormones and cytokines measured do not appear to be involved in the pathophysiology of these myopathies, at least in an endocrine, as opposed to a para-or autocrine, role.