Stem Cell Therapies for Type I Diabetes

Diabetes mellitus is a chronic metabolic disease that results in high levels of glucose in the blood. Normally, glucose is transported into cells from the blood for energy, and this transport is initiated in response to the hormone, insulin. In diabetic patients, cellular glucose uptake is defective, in part due to the inability of cells to respond to insulin, or the inability of the body to produce the insulin itself. According to the International Diabetes Foundation, 366 million people worldwide had been diagnosed with diabetes in 2011, and this number is continuing to increase in every country (http://www.idf.org/). It is an especially challenging health problem, as treatments to both control hyperglycemia as well as the debilitating side effects of diabetes, such as injury to the blood vessels and nerves, must be addressed. Amongst the three types of diabetes (Type I autoimmune, gestational and Type II – adult onset), Type II diabetes is the most prevalent, in which hyperglycemia is uncontrolled due to the body’s inability to produce enough insulin or due to the body’s inability to respond appropriately to lower the blood glucose level. In contrast, in patients with Type I diabetes (TID), insulin-producing beta (β) cells are destroyed by the immune system. Studies of TID by many groups have provided extensive insight to the fields of immunological tolerance and pancreatic developmental biology. In this chapter, we will briefly describe TID, provide a synopsis of pancreatic β cell development in mice as compared to humans, review of some of the medical treatments currently available for TID, and discuss current studies that have explored the use of stem cells as alternative possible therapies for TID.