"To meet the needs of the millions suffering from type 1 diabetes, we must find new donor sources to allow large-scale application of islet cell transplantation in humans," said Dr. Larsen. "While there is much work to be done these studies suggest that the rejection response to porcine islets can be surmounted."
"The next step is to prove that these neonatal porcine islet cells could become a source for human transplantation," said Dr. Rajotte. "It's hoped that within the next three to five years, we will be transplanting patients with pig islets once we prove that it is safe."
Using a relatively simple and reproducible method of obtaining large numbers of islets from neonatal pig pancreata developed at the U of A, the researchers then transplanted islets comprised of endocrine and endocrine precursor cells into the monkeys. In vivo, these cells have been shown to proliferate, differentiate and reverse hyperglycemia in immunodeficient diabetic mice and allogeneic out-bred pigs.
However, humans and Old World primates have naturally occurring antibodies that are directed against antigens that can cause hyperacute or acute humoral rejection. To combat that, the researchers administered an anti-IL-2 receptor and anti-CD154 (H106) antibody, while maintaining immunosuppression using sirolimus and belatacept (a second-generation high affinity derivative of CTLA4-Ig)9-11 on diabetic rhesus macaques transplanted with neonatal porcine islets.