Aim. Our aim was (1) to determine the frequency of insulin resistance (IR) in patients with Duchenne/Becker muscular dystrophy (DMD/BMD), (2) to identify deleted exons of DMD gene associated with obesity and IR, and (3) to explore some likely molecular mechanisms leading to IR. Materials and Methods. In 66 patients with DMD/BMD without corticosteroids treatment, IR, obesity, and body fat mass were evaluated. Molecules involved in glucose metabolism were analyzed in muscle biopsies. Results show that 18.3%, 22.7%, and 68% were underweight, overweight, or obese, and with high adiposity, respectively; 48.5% and 36.4% presented hyperinsulinemia and IR, respectively. Underweight patients (27.3%) exhibited hyperinsulinemia and IR. Carriers of deletions in exons 45 (OR = 9.32; 95% CI = 1.16–74.69) and 50 (OR = 8.73; 95% CI = 1.17–65.10) from DMD gene presented higher risk for IR than noncarriers. We observed a greater staining of cytoplasmic aggregates for GLUT4 in muscle biopsies than healthy muscle tissue. Conclusion. Obesity, hyperinsulinemia, and IR were observed in DMD/BMD patients and are independent of corticosteroids treatment. Carriers of deletion in exons 45 or 50 from DMD gene are at risk for developing IR. It is suggested that alteration in GLUT4 in muscle fibers from DMD patients could be involved in IR.
Inflammation described in patients with Duchenne muscular dystrophy (DMD) may be related to loss of muscle function or to obesity. It is unknown if circulating proinflammatory cytokines (IL-6, IL-1, and TNF-α) levels are associated with muscle function. The purpose was to evaluate whether an association exists between systemic inflammation with muscle function and nutritional status in DMD patients. In 66 DMD patients without corticosteroid treatment, the following were evaluated in serum: cytokines (IL-1, IL-6, and TNF-α), C-reactive protein (CRP), leptin, adiponectin, and creatine kinase (CK). Muscle function was evaluated using Vignos Scale. Patients with better muscle function had the highest concentration of CK, IL-1, and TNF-α compared with less muscle function. No differences in IL-6 and adiponectin concentration were identified among groups with different levels of muscle function. Also, no differences were observed in the concentration of cytokines among groups with different nutritional status levels (underweight, normal weight, and overweight/obese). However, CRP and leptin were increased in the obese group compared with normal and underweight subjects. Systemic inflammation is increased in patients with better muscle function and decreases in DMD patients with poorer muscle function; nevertheless, systemic inflammation is similar among different levels of nutritional status in DMD patients.
Age dependent changes in BD in boys with DMD may be due to endogenous metabolic factors related to the underlying disease process and to disease-related mobility impairments. This article is protected by copyright. All rights reserved.
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