Gene therapy for diabetes: reinventing the islet.

A cure for type 1 (insulin dependent) diabetes might be found in generating surrogate insulin-producing cells to replace beta cells. A gene therapy strategy using constructs designed to allow glucose-regulated insulin transcription when delivered to non-pancreatic tissues has not fully recreated the stringent control of blood glucose provided by the beta cell. A more promising gene therapy approach has been to express pancreatic endocrine developmental factors, such as PDX-1, NeuroD/BETA2 and Neurogenin 3, to promote differentiation of non-endocrine cells towards a beta cell or islet phenotype, enabling these cells to synthesize and secrete insulin in a glucose-regulated manner. Further research is necessary, however, to better define the most effective pro-endocrine factors and the most amenable cell types to achieve transdifferentiation for beta cell replacement.