February 15, 2005
St. Paul, Minn. — It's been two and a half years since surgeons at the U of M inserted a tiny cluster of islet cells into Lynn Hopperstad's liver. Islet cells come from the portion of the pancreas that produces insulin. Once surgeons transplanted those cells into Hopperstad, her body immediately started producing insulin.
The process is remarkable, considering people with Type 1 diabetes, like Hopperstad, produce little or no insulin at all.
"I am no longer considered diabetic, and the change in my life has been huge," says Hopperstad.
Hopperstad was one of eight patients who enrolled in a University of Minnesota study to see if an islet transplant from a single pancreas would work.
At first, all eight were able to stop using insulin. Two years later, Five of the eight are still insulin-independent. The findings were reported in the latest edition of the Journal of American Medical Association.
Hopperstad says she was the perfect candidate for the experimental procedure, because her body couldn't tell her when her blood sugar was low.
Diabetics like Hopperstad must take insulin shots and monitor their blood sugar to prevent swings in blood sugar levels. If they don't regulate their blood sugar, diabetics increase their chances for kidney failure, stroke and heart failure.
In some cases, patients can't effectively regulate their blood sugar even with insulin. Without warning, those people could go into a coma or die. Hopperstad says she had to test her blood sugar at least seven times a day.
"Every time I got in the car I tested my blood sugar. I had to test my blood sugar if I was doing yard work. If I was doing any strenuous activity I would have to stop after an hour, just to make sure my blood sugar was doing OK," says Hopperstad.
Islet transplants have been performed successfully since 2000. The procedure is safer and easier than transplanting an entire pancreas, which is not as common a procedure.
In order for an islet transplant to be successful, surgeons needed to take islet cells from several donated pancreases. By better matching the cells from donated organs with patients, and improving technology, the U of M's Bernhard Hering says his team can now do the procedure with one pancreas.
"What this study shows is not a cure of diabetes. But it shows very clearly that with higher efficiency -- comparable to the efficiency of a pancreas transplant at least in a select group of recipients -- we can achieve very favorable outcomes," says Hering.
Hering says the findings are important because there aren't enough organs for people who need them. He says showing that the procedure can be successful with one pancreas increases the likelihood that it will be done more often.
The Mayo Clinic's Robert Rizza, president-elect of the American Diabetes Association, says the research is promising. But Izza still worries there won't be enough donated organs to do a high number of transplants. Izza also says researchers need to learn how long the transplanted cells will be effective.
"The concern is having enough organs. And the second concern is being sure that once the islets or organs are transplanted, that they function over the long term," says Rizza.
Other researchers say about half of the patients who received islet transplants are still insulin-dependent, which raises questions about whether the procedure should be done at all.
That's because patients who receive a transplant still won't lead perfectly healthy lives. They'll have to take anti-rejection medicine for the rest of their lives. They're also more likely to get sick, since they'll have a weaker immune system.
About one million people in the United States have Type 1 diabetes, which usually is diagnosed at an early age. The procedure is not considered effective for treatment of Type 2 diabetes, which affects 16 million people in the U.S, since people with Type 2 diabetes produce some insulin.
Nevertheless, Richard Bergenstal with the International Diabetes Center at Park Nicollet Hospitals says the procedure should give hope to people with Type 1 diabetes.
"This is going to be a limited process initially, but at least it's hopeful that it can succeed," says Bergenstal. "We need to overcome a few more hurdles on the immune-suppressing medications you take, and the need for more islet cells. But at least it gives people hope that it is possible."
The U of M's Hering says he hopes to do another clinical trial with a larger number of patients.