Protection of human pancreatic islets using a lentiviral vector expressing two genes: cFLIP and GFP

Pancreatic islet transplantation can provide insulin independence to diabetic patients. However, apoptosis of islets often leads to early graft failure. Genetic engineering with protective gene(s) can improve the viability of these cells. Here we show successful transduction of human islets with a feline immunodeficiency virus (FIV) vector expressing both a cytoprotective (cFLIP) gene and the green fluorescent protein (GFP). Despite using low virus titers to maximize safety, transduced islets expressed both genes, resulting in improved beta-cell metabolic activity and viability. Although only approximately 10% of total islet cells were transduced, the significant viability advantages suggest a "barrier" effect in which protecting the periphery of the islet shields the core. These results provide the first demonstration that a lentiviral vector can express two genes in islets. Furthermore, the engineered islets are resistant to a variety of apoptotic stimuli, suggesting the potential of this approach in enhancing the viability of transplanted cells.