by Playfuls Staff |
27th February 2006
Islet cell xenotransplantation presents a promising near-term solution to the critically low islet cell supply for humans suffering from type 1 diabetes, according to researchers from the Emory Transplant Center, the Yerkes National Primate Research Center of Emory University and the University of Alberta, Canada. The Emory/Yerkes researchers [more] successfully transplanted and engrafted insulin-producing neonatal porcine islet cells harvested by the University of Alberta researchers into diabetic rhesus macaque monkeys, restoring the monkeys' glucose control and resulting in sustained insulin independence. This research, published in the February 26 advanced online edition of Nature Medicine, also examines the effectiveness of a costimulation blockade-based regimen developed at Emory proven to have fewer toxic side effects than currently used immunosuppressive regimens, and provides essential answers to the possibility of cross-species viral transmission, a common concern of xenotransplantation use in humans.
Islet cell transplantation has been successful in reversing type 1 diabetes in humans, but the limited availability of islet cells greatly diminishes the possibility of meeting the medical needs of more than one million Americans who have the disease. Each year, only 3,000 to 4,000 donor organs are available, and each organ can only produce enough cells for, at most, one transplant.
While the Emory/University of Alberta findings are similar to the recently publicized research conducted by the University of Minnesota, the nonhuman primates in this study exhibited improved glucose control and sustained insulin independence using a simpler, less toxic CD28/CD154 costimulation blockade-based regimen developed by Dr. Larsen and Kenneth Cardona, MD, of the Emory Transplant Center and the Yerkes Research Center. Belatacept, a key ingredient in the costimulation blockade regimen that selectively blocks the second of two cellular signals (costimulatory signals) the body needs to trigger an immune response, was developed between investigators at Bristol Myers-Squibb Pharmaceutical Research Institute and by Dr. Larsen and Thomas Pearson, MD, DPhil, of the Emory Transplant Center. The costimulation blockade regimen used in this study is less complex than the immunosuppressant compounds used in previous research, and its simplicity will prove more applicable in clinical use, according to Dr. Cardona.
The neonatal porcine cells used in this study were harvested using a novel technique developed by Gregory S. Korbutt, MD, and Ray V. Rajotte, MD, of the Surgical-Medical Research Institute at the University of Alberta. "The harvesting method is both simple and reproducible, but the significant advantage of the technique is that the neonatal islet cells retain their growth potential post-transplant," said Dr. Rajotte, founder and director of the University of Alberta's Islet Transplantation Group. "The next steps are to prove porcine islet cells can be a source for human transplantation and to verify the safety of the transplant procedures. It's hoped within the next three to five years, we will begin testing neonatal porcine islet transplants in human patients."
