Frontiers in transplantation of insulin-secreting tissue for diabetes mellitus

Transplantation of insulin-secreting tissue represents a physiologic approa ch to reverse diabetes mellitus. Pancreas transplants yield a remarkable en hancement in quality of life and appear to modify the devastating neurovasc ular complications of diabetes. A more attractive approach is transplantati on of insulin-secreting cells,a procedure of low invasiveness with the exci ting prospect of modulating graft immunogenicity be fore transplantation, s o as to minimize requirements for toxic immunosuppressive drugs. The Surgic al-Medical Research Institute at the University of Alberta in Edmonton, and several others centres throughout the world, has demonstrated that islet c ell transplants can reverse insulin dependence and induce remarkable glycem ic stability for several years. However, widespread success has been denied because of insufficient donor tissue, early failures to reverse insulin de pendence and the loss of graft function with time. Promising new research a pproaches to these problems are reviewed, including xenogeneic sources of c ells, engineering islet cells with genes that induce expression of immunopr otective molecules, and neogenesis factors that may sustain populations of transplanted beta cells.