và tuyến tụy trưởng thành có khả năng tái sinh sau khi pancreatectomy một phần (92) và viêm (93) ít nhất là ở loài gặm nhấm, từ lâu đã được đầu cơ như sự tồn tại của một tế bào trong tuyến tụy (gần đây đã xem xét trong refs 75 và 94). Trong buổi hòa nhạc với những phát hiện cơ thể sống | Chapter 1 Embryonic Stem Cells 15 91 and the adult pancreas has regenerative capacity after partial pancreatectomy 92 and inflammation 93 at least in rodents there has long been speculation as to the existence of a progenitor cell within the pancreas recently reviewed in refs. 75 and 94 . In concert with these in vivo findings several groups have demonstrated that culture of pancreatic ductal tissue can result in growth of islet-like tissues from both mice 95 and humans 96 97 . In each case an expansion of p cell-like tissue was observed as demonstrated by expression of pdxl and insulin as well as insulin secretion in response to glucose. Ramiya and colleagues showed that their in vitro generated islets could reverse insulindependent diabetes in an NOD mouse model 95 . Most evidence suggests ductal or acinar tissue as the source of putative islet stem cells unfortunately however the characterization and isolation of an islet stem cell has been hindered by the absence of specific cell surface markers. Thus none of these studies were able to identify a stem cell population that is responsible for the regenerative growth of islet tissues. Much of the impetus to isolate a pancreatic islet stem cell is for the development of a therapy for patients with type I diabetes whose insulin-secreting p cells are destroyed by a poorly understood autoimmune response. Today some of these patients are eligible for whole organ or islet cell transplantation but the number of cadaver organs available is limiting. If islet stem cells could be isolated from cadaver organs that were capable of unrestricted growth and differentiation in vitro it would facilitate the treatment of many more patients than is currently possible. One might envision a scenario in which a bank of pancreatic islet stem cells derived from nondiabetic cadaver donors was created each line with a different histocompatibility. Similar to the current situation with human ES cell lines there are ethical and scientific .
