Genes and engineered cells as drugs for type I and type II diabetes mellitus therapy and prevention

Despite the manageability of diabetes mellitus, complications associated with the disorder necessitate novel approaches to prevent immune-mediated impairment and destruction in type 1 diabetes, as well as the pancreatic insufficiency and peripheral resistance to insulin in type 2 diabetes. Islet transplantation is evolving into a clinical reality to treat type 1 diabetics and novel uses of gene engineering technology promise to result in tolerance to auto-, allo- and xenoantigens as well as microenvironment-specific immunosuppression. Through the use of a variety of gene delivery vehides, an increasing number of studies demonstrate the feasibility of shielding islet transplants and surrogate beta cells from immune rejection by the local secretion of immunosuppressive soluble molecules and anti-apoptotic factors. Although the achievements of gene and cell therapy in type 2 diabetes mellitus are less clear, seminal studies demonstrate the relevance of this approach to the treatment and perhaps prevention of the underlying causes of the disease, including obesity and insulin resistance. In this review, we attempt to illustrate pivotal studies demonstrating the suitability of genes and cells as drugs in type 1 and type 2 diabetes mellitus, and also provide some other targets that may be suitable for clinical utility.