| Abstract: |
Role of Stem Cells in Treatment of Diabetes MellitusType 1 and type 2 diabetes, though different diseases, both involve inadequate cell mass of insulin-producing β cells, the most abundant cell type of pancreatic islets of Langerhans. Insulin injections alleviate hyperglycemia in the majority of diabetic patients. However, insulin therapy cannot provide the finely tuned control of glucose homeostasis afforded by native pancreatic islets. As a result, diabetic patients commonly develop multiple life-threatening complications, such as cardiovascular and kidney disease, neuropathy, and blindness. Recent successes in pancreatic islet transplantation fueled new hope that this procedure could significantly improve the quality of life for diabetic patients. Unfortunately, because the islets needed for transplantation are obtained from cadaveric donors only, few patients can receive this therapy. The shortage of islets could potentially be overcome by deriving them from alternative sources stem cells. An effective cell-replacement strategy depends on the development of an abundant supply of beta cells and their protection from recurring immune destruction. Stem/progenitor cells, which can be expanded in tissue culture and induced to differentiate into multiple cell types, represent an attractive source for generation of cells with beta-cell properties: insulin biosynthesis, storage, and regulated secretion in response to physiologic signals. Embryonic stem cells have been shown to spontaneously differentiate into insulin-producing cells at a low frequency, and this capacity could be further enhanced by tissue culture conditions, soluble agents, and expression of dominant transcription factor genes. Progenitor cells from fetal and adult tissues, such as liver and bone marrow, have also been shown capable of differentiation towards the beta-cell phenotype.
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