Pig-to-monkey transplants may herald cure for diabetes

Researchers have suppressed diabetes in laboratory monkeys by transplanting pancreatic tissue from pigs, meaning pig transplants could eventually cure childhood diabetes in humans. The monkeys have survived for more than two months without the insulin that had kept them alive.

Tissue rejection - far more violent in transplants between species - was controlled by drugs, which prevented the monkey immune system from attacking the alien pig tissue.

Professor Bernhard Hering, who led the study at the University of Minnesota, said the pig's islets of Langerhans, the insulin-producing cells of the pancreas, had kept making insulin for more than 70 days. "We have been able to reverse diabetes in past islet studies, [but] we had only seen two to three- week survival times before the graft was lost due to the overwhelming rejection response," Professor Hering told the American Transplant Con-gress in Washington DC yesterday. "The survival times we are reporting on today should only increase as we further optimise the immunosuppressive regimens."

Eleanor Kennedy, research manager for the charity Diabetes UK, said: "Anything that overcomes the need for human islets is a big advance."

Childhood or type-1 diabetes affects 400,000 people in Britain alone and typically is caused by the pancreas's inability to produce enough insulin, the vital hormone controlling glucose sugar levels in the blood. Regular injections of insulin can control the disorder but, apart from the inconvenience and pain of using needles, there is always a risk of using too much or too little of the hormone.

One per cent of diabetics overreact to the smallest change in levels of glucose in the blood and insulin injections do not work well for them. They would probably be the first candidates for pig-to-human transplants.

Scientists had proposed that pigs could be genetically engineered to produce organs and tissues more compatible with the human immune system, and pancreatic transplants are candidates for such research.

Professor Hering's research was sponsored by Immerge BioTherapeutics, a company investigating ways of making xenotransplantation - the transfer of organs and tissues from animals to humans - safe and effective

Julia Greenstein, president of BioTherapeutics, said experiments on genetically modified pigs had already demonstrated the possibility of producing porcine tissue and organs that in principle were well tolerated by other animals, such as primates,