Pancreatic islet regeneration is a major highly competitive research field in regenerative medicine. One reason why the field is so competitive is that the target cells, the pancreatic islet cells that secrete insulin, are easy to experimentally evaluate for a sophisticated model of transplantation.
Induced pluripotent stem (iPS) cells are strong candidates for pancreatic islet cell regeneration. However, the theoretically regenerated islets induced from type 1 diabetes patients may have persisting unsolved pathogenesis such as autoimmune reactivity. As for present clinical options, the severe "type 1 diabetic" patients, whose levels of endocrine insulin, which induces life-threatening hypoglycemia, are negative, have few choices for replacement therapies.
Pancreatic organ and islet transplantations are final options for these T1D patients. Islet transplantations have never been covered by medical insurance in Japan, but pancreatic organ transplantation have. Basically, islet transplantation is a cell therapy that could expand applications to such methods as porcine xenografts. To solve the problem of a shortage of donors, the usage for porcine islets is an extremely attractive challenge. Furthermore, bioartificial islets consisting of porcine islets with encapsulation would arise as an additional option for clinical transplantation. Lastly, as one approach to chronic pancreatitis, islet autotransplantations have been carried out in Japan without coverage by medical insurance. Because alcohol-induced patients are dominant in Japan, the backgrounds of patients suffering with pancreatitis here are entirely different from other countries.
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