Pig cells reverse diabetes in monkeys

Feb 21 2006

A team of researchers in the U.S. have successfully reversed diabetes in monkeys using transplanted islet cells from pigs.

The researchers at the University of Minnesota's Diabetes Institute for Immunology and Transplantation, say they hope to increase islet supply to cure type 1 diabetes; they believe such transplants could provide a diabetes cure within a decade.

The team were able to reverse the condition in monkeys by transplanting cell clusters, known as islets, from pig pancreases. Islets are groups of cells located in the pancreas that make hormones that help the body break down and use food.

They worked to perfect a combination of drugs and the survival of the pig islet transplants was made possible with this new immunosuppressive protocol.

This meant the genetic modification of donor pigs or the coating or encapsulation of the donor islets, was not needed.

Researchers have already had success reversing type 1 diabetes in humans through islet transplantation, but the demand for islet cells considerably outweighs the supply.

So in order to make islet transplantation a viable solution for the tens of thousands of people with difficult-to-manage diabetes, a safe and reliable source of islet cells needed to be found.

Working towards the goal of using this technology to help people, Spring Point Project, a non-profit corporation, has taken concrete steps to build and operate biosecure barrier facilities to raise high-health pigs for planned pig islet transplant trials in humans.

As it will take time to build such biosecure facilities for using animal tissues in humans, the Spring Point Project will proceed on a parallel track with the research at the University.

The aim is to have suitable donor pigs available by the time the University has refined the immunosuppressive treatment to a such a point that makes it safe for clinical trials to begin.

Associate professor of surgery and lead investigator Bernhard Hering says if the research continues to be successful, he believes it may be possible to start clinical trials in humans in the next three years.

Professor Hering says however that the drugs used to suppress cell rejection have severe side-effects in humans and need to be refined.

He says that now they have identified the critical pathways involved in immune recognition and rejection of pig islet transplants, they can begin working on better and safer therapies.

The process is performed by isolating islet cells from a donor pancreas and transplanting them into the portal vein of the liver in people with diabetes.

If successful, transplanted islets will sense blood glucose levels on a minute-to-minute basis and release the appropriate amount of insulin to achieve tight blood glucose control.

Insulin injections are no longer needed in recipients of successful transplants.

Transplantation also offers hope in reducing the risk of developing debilitating secondary complications of diabetes, such as damage to the heart and blood vessels, eyes, nerves, and kidneys.

The advantage of islet transplantation is that it stops patients from having to have the regular insulin injections.

The heart valves of pigs have been used in hundreds of thousands of heart transplants, and pig cells are widely used in the treatment of Parkinson's disease.

The research is published in Nature Medicine.