Hydrogen Peroxide Production Is Not Primarily Increased in Human Myotubes Established from Type 2 Diabetic Subjects

• Published in: The journal of clinical endocrinology and metabolism 2011-09, Vol.96 (9), p.E1486-E1490
• Main Authors: Minet, A. D, Gaster, M
• Format: Article
• Language: English
• Subjects: Cell Differentiation; Cells, Cultured; Diabetes Mellitus, Type 2 - metabolism; Humans; Hydrogen Peroxide - metabolism; Membrane Potential, Mitochondrial - physiology; Middle Aged; Mitochondria, Muscle - metabolism; Muscle Fibers, Skeletal - metabolism; Muscle, Skeletal - metabolism; Obesity - metabolism; Oxidative Stress - physiology; Reactive Oxygen Species - metabolism; Superoxides - metabolism
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2011-1384

Context: Increased oxidative stress and mitochondrial dysfunction have been implicated in the development of insulin resistance in type 2 diabetes. To date, it is unknown whether increased mitochondrial reactive oxygen species (ROS) production in skeletal muscle from patients with type 2 diabetes is primarily increased or a secondary adaptation to environmental, lifestyle, and hormonal factors. Objective: This study investigates whether ROS production is primarily increased in isolated diabetic myotubes. Setting: Mitochondrial membrane potential, hydrogen peroxide (H2O2), superoxide, and mitochondrial mass were determined in human myotubes precultured under normophysiological conditions. Furthermore, the corresponding ATP synthesis was measured in isolated mitochondria. Patients: Muscle biopsies were taken from 10 lean subjects, 10 obese subjects, and 10 subjects with type 2 diabetes; satellite cells were isolated, cultured, and differentiated to myotubes. Results: Mitochondrial mass, membrane potential/mitochondrial mass, and superoxide-production/mitochondrial mass were not different between groups. In contrast, H2O2 production/mitochondrial mass and ATP production were significantly reduced in diabetic myotubes compared to lean controls (P < 0.05). The ATP/H2O2 ratios were not significantly different between groups. Conclusions: Our result indicates that the ROS production is not primarily increased in diabetic myotubes but rather is reduced. Moreover, the comparable ATP/H2O2 ratios indicate that the reduced ROS production in diabetic myotubes parallels the reduced ATP production because ROS production in diabetic myotubes must be considered to be in a proportion comparable to lean. Thus, the increased ROS production seen in skeletal muscle of type 2 diabetic patients is an adaptation to the in vivo conditions.