In vivo and in vitro approaches to induce beta cells from stem and progenitor cells

Diabetes or diabetes mellitus which is the correct medical term is a medical condition were the affected person lack the ability to regulate his or her blood glucose levels. This inability is directly due to the fact that the insulin producing cells, residing in the pancreas, can’t meet the body’s demand for insulin. It is estimated that close to 200 million people are suffering from diabetes today and this number is predicted to double within 20 years. Of the approximately 200 million people suffering from diabetes today approximately 20 million are in dependent on daily injections of insulin. Being dependent on exogenous insulin is not only an inconvenience it also increase the risk for several medical complications such as stroke, heart disorders, kidney failure, retinopathy, atherosclerosis and impaired wound healing. The major risk factor for all these complications is long periods of high blood sugar levels that is damaging to thin blood vessels and nerves. Even in the best of situations the blood sugar levels of a diabetic with need for daily insulin injections can never be as well controlled as in a healthy individual. Increased understanding in the developmental processes behind the formation of the pancreas, and more specifically the insulin producing β-cells could result in new treatments for diabetics. By imitating the in vivo conditions generating pancreatic development scientist are now able to induce embryonic stem cells to differentiate into pancreatic progenitors as well as insulin producing β-cells in vitro. These in vitro generated pancreatic cells might in the future serve as a donor source for transplantations, thereby restoring the insulin producing capability of diabetic patients. An alternative approach to restore insulin production in diabetics is to influence cells in the pancreas to generate more insulin producing cells. To successfully achieve this, what cell types have the capacity to generate β-cells needs to be appreciated. In this thesis papers concerning in vitro differentiating of embryonic stem cells towards a pancreatic fate as well as in vivo studies in basic pancreas development are presented and discussed