U researcher Bernhard Hering has successfully reversed diabetes for up to six months in monkeys, using transplanted insulin-producing islet cells from pig pancreases.
U researcher reverses diabetes in monkeys
Work using pig islet cells is a critical step in making transplants available on an unlimited basis
By Deane Morrison
February 21, 2006
In a medical first, University researchers have reversed diabetes for up to six months in monkeys, using transplanted insulin-producing islet cells from the pancreases of pigs. Led by associate professor Bernhard Hering of the surgery department's Diabetes Institute for Immunology and Transplantation, the team used new methods to suppress rejection of the transplants. The islets survived without the necessity of genetically modifying the pig donors to make them more compatible with the monkeys' immune systems or of coating or encapsulating the islets for protection. The work is published online in the journal Nature Medicine . It was already known that transplanted islets could reverse type 1 diabetes, but the demand from the tens of thousands of patients with hard-to-manage diabetes far outweighs the supply of human islets. "These results suggest it is feasible to use pig islet cells as a path to a far-reaching cure for diabetes," said Hering in a news release. "Now that we have identified critical pathways involved in immune recognition and rejection of pig islet transplants, we can begin working on better and safer immunosuppressant therapies with the eventual goal of bringing the treatment to people."
"These results suggest it is feasible to use pig islet cells as a path to a far-reaching cure for diabetes," said Hering.In the study, 12 monkeys with experimentally induced diabetes were treated with pig islets. The islets were injected into the portal vein, which carries nutrient-laded blood from the intestines to the liver. The islets took up residence in their livers, where they did what islets do: They monitored blood glucose levels and produced insulin as needed to maintain normal levels. All the monkeys achieved normal blood glucose levels and independence from insulin injections. The researchers' central achievement was identifying a protocol for suppressing rejection of the transplants that allowed monkeys to survive for at least three months. As he continues the research, Hering says it may be possible to begin clinical trials in humans in three years. To help make that happen, Spring Point Project, a nonprofit corporation, is taking serious steps to build and operate facilities to raise healthy donor pigs free from contamination by harmful bacteria, viruses, or other pathogens. At this point, the techniques used to suppress rejection of the islets are too severe for use in patients; however, the goal is to refine the techniques sufficiently by the time suitable donor pigs become available. If successful, a one-time transplant would eliminate the need for insulin injections and reduce the risk of developing such diabetic complications as damage to the heart, blood vessels, eyes, nerves, and kidneys.