Skeletal muscle metabolism in the pathology and treatment of type 1 diabetes

Type 1 diabetes is characterised by the absence of circulating insulin due to the autoimmune destruction of beta-cells in the pancreas. Patients are traditionally treated with multiple daily injections of exogenous insulin analogues. However, although these therapies improve quality of life, they are associated with the risk of hypoglycemic episodes and do not prevent the development of debilitating secondary complications. For these reasons, there is increasing demand for new therapies and preventions. One approach is the use of viral or non-viral gene therapy to modify skeletal muscle to produce and secrete insulin into the circulation and/or to increase muscle glucose uptake. Skeletal muscle is a desirable target tissue for the treatment of diabetes not only for its central role in whole body metabolism and glucose homeostasis, but also for its accessibility and amenability to many potential gene therapy technologies. Here, we review the basic metabolic principles of skeletal muscle in the absorptive and post-absorptive states at rest and during exercise and discuss how these processes are affected in type 1 diabetes. Finally, current viral and non-viral strategies for modification of skeletal muscle and their application to the treatment of type 1 diabetes are also presented.