Nitric oxide synthase in skeletal muscle fibers of patients with type 2 diabetes

There is increasing interest in the role of nitric oxide (NO) in common metabolic disorders such as type 2 diabetes (T2D) however, fiber-type specific changes in NO synthase (NOS) expression in skeletal muscle of T2D patients remain to be elucidated. Here we investigated fiber-type related NOS expression in the Vastus lateralis muscle of T2D patients compared with healthy individuals with normal glucose tolerance (NGT). Cytophotometrical assay did not reveal any quantitative differences between NOS expression in muscles from NGT and T2D subjects. Positive NOS immunoreactivity in the V. lateralis of T2D patients was found to be associated with fast-oxidative glycolytic (FOG) muscle phenotype. This indicates that NOS expression in T2D patients correlates both with skeletal muscle fiber type distribution and the activity of oxidative and glycolytic enzymes.