Myostatin Inhibition as an Adjuvant Therapy in Type 1 Diabetes Mellitus

While Type 1 Diabetes Mellitus (T1DM) is characterized by hypoinsulinemia and hyperglycemia, persons with T1DM also develop insulin resistance and recent studies have demonstrated that insulin resistance is a primary mediator of the micro and macrovascular complications that invariably develop in this chronic disease. Therefore, we hypothesized that a reduction in circulating myostatin (a TGF‐beta family member known to regulate muscle mass) in a T1DM mouse model would improve skeletal muscle health, resulting in an increased insulin sensitivity and a reduction in blood glucose. To that end, we crossed Akita diabetic mice with the Myostatin Ln/Ln mouse line (which displays a ~60% reduction in myostatin levels) to generate a novel mouse line (Myostatin Ln/Ln ; Akita +/− ). Our data support the hypothesis that reducing circulating myostatin levels prevented the loss of skeletal muscle mass observed in T1DM, as well as significantly increasing Glut1 and Glut4 transporter densities with the end result being an increased glucose uptake in response to an insulin tolerance test (ITT). These positive changes in T1DM skeletal muscle health resulted in significant reductions in resting blood glucose levels and other diabetic symptoms (hyperphagia, polydypsia), even in the absence of exogenous insulin. Taken together, these studies provide a foundation for considering pharmacological myostatin inhibitors as an adjuvant therapy in T1DM as a means to delay the development of diabetic complications. Support or Funding Information This work is funded by a grant from Natural Sciences and Engineering Research Council of Canada to TJH