In research at Washington University School of Medicine in St. Louis, a method of treating diabetes via porcine (pig) embryonic pancreatic cell transplant, followed by adult pancreatic cell transplant, has proven successful in rats (see link).
The method is noteworthy for the fact that it results in normal insulin production without the need for anti-rejection drugs, a chronic stumbling block of cell therapy options for diabetes. The achievement of avoiding anti-rejection drugs is apparently the result of the embryonic state of the pig pancreatic cells, which induce the recipient's immune system to accept the transplanted cells. While the embryonic cells transplanted lead to insulin production, it does not produce high enough insulin levels. The higher insulin-producing adult pancreatic cells (also from pigs) are then transplanted to the patient, achieving normal insulin levels without stimulating an immunogenic response.
The method has yet to be tried on primates as a precursor to human testing.