Stem-cell therapy for diabetes cure : how close are we?

Transplantation of insulin-producing cells offers a promising therapy to treat diabetes. However, due to the limited number of donor islet cells available, researchers are looking for different sources of pancreatic islet progenitor or stem cells. A stem cell with extensive proliferative ability may provide a valuable source of islet progenitor cells. Several studies have demonstrated that a progenitor/stem-cell population can be expanded in vitro to generate large numbers of islet progenitor cells. However, efficient and directed differentiation of these cells to an endocrine pancreatic lineage has been difficult to achieve. We discuss here various pancreatic islet stem cells that we and others have obtained from embryonic, fetal or adult human tissues. We review the progress that has been achieved with pancreatic islet progenitor cell differentiation in the last 2 decades and discuss how close we are to translate this research to the clinics.