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Pushing Forward With Islet Transplants

Pancreatic islets can be transplanted into a diabetic patient's liver and help them begin producing their own insulin.

Pancreatic islets can be transplanted into a diabetic patient’s liver and help them begin producing their own insulin.

Like every person with type 1 diabetes, Joey Knoop’s life was a balancing act. She was constantly thinking about her blood sugar, calculating how much insulin she needed to give herself to cover the food she had eaten, and testing and retesting her glucose levels. But despite her best efforts, Joey, who is 49, spent the first 25 years of her life with diabetes experiencing severe blood sugar spikes and crashes.

“My doctors kept thinking I was cheating. I could not convince anybody how hard I was trying,” she said in an article for Medicine on the Midway in 2011. “Even on an insulin pump, I was having a terrible time.”

An islet transplant helped get Joey Knoop’s severe diabetes under control, and she no longer needs insulin injections.

Until recently, the only option left for patients like Joey was a full pancreas transplant. But the University of Chicago is testing an experimental but promising alternative: islet transplantation.

Type 1 diabetes is an autoimmune disease caused when the body destroys its own pancreatic beta cells, which produce insulin, a hormone crucial for regulating blood glucose. Usually type 1 diabetics can manage the disease by injecting insulin and carefully managing their diets.

Joey had what’s known as labile, or brittle diabetes. Her body was extremely sensitive to insulin, so that just one extra unit could cause her to black out, faint, or even have a seizure with little warning. Even patients on the strictest diets, with established exercise routines and testing regimens, find it difficult to manage their blood glucose levels with this condition. And it has a huge impact on quality of life. It’s difficult to work, and they’re afraid to drive or be alone for fear of suddenly losing consciousness.

A whole pancreas transplant offers the best chance of a normal lifestyle for patients like Joey, but it’s major surgery with substantial risk for problems. The donor pancreas might be lost immediately after transplant due to complications, or the patient may develop a severe infection after the operation.

Islet transplants offer a second, much less-invasive option to accomplish the same thing: getting the body to produce its own insulin again. The University of Chicago has been performing islet transplants as part of clinical studies since 2004, and has successfully transplanted nine patients, including Joey.

During the procedure, doctors separate the islets, which are like mini-organs containing hundreds of thousands of cells, from a deceased donor’s pancreas. The islets need a good blood supply in order to thrive after implantation, so they are injected into the patient’s liver, which has a robust enough blood supply to handle the additional tissue. Since the islets are from another person, recipients still need to take immunosuppressive medications to prevent rejection, as with a whole organ transplant.

Piotr Witkowski, MD, PhD

Piotr Witkowski, MD, PhD, director of pancreas and islet cell transplant, said the goal is for the new islets to begin producing insulin so that the recipient no longer needs injections, effectively curing them of diabetes.

“Overall the quality of life of the patient after islet transplant is much better than when they’re having so many episodes of hypoglycemia. And we’re able to adjust the dose of the immunosuppression medication so they don’t have side effects that compromise their daily life,” he said.

The process can take up to three infusions. Witkowski said the first procedure usually cuts the amount of insulin patients need in half, and a second infusion two months later usually gets them off insulin completely. Sometimes they require a third infusion a few years later as their bodies adjust. After 5 years, most of the patients are still protected from the debilitating hypoglycemic attacks they suffered prior to transplant; and 50 to 60 percent of patients are still off insulin completely. Joey has been off insulin for eight years.

Witkowski is currently working on a new clinical trial protocol to improve the results of the procedure by using a new medication that may help newly transplanted islets survive after infusion. He has already transplanted three patients under this new protocol, and hopes to recruit more.

While islet transplantation is still experimental and only offered in the most severe cases, Witkowski hopes this can become an option for all patients with type 1 diabetes.

“The ultimate goal is to get rid of the immunosuppression and still have a way to protect the islets from rejection,” he said. “We’re trying to improve this process of transplantation and immuno-protection so it can be offered to every type 1 diabetic one day.”

To find out more about islet transplant clinical trials at the University of Chicago, including selection criteria, please visit: http://www.uchospitals.edu/specialties/transplant/pancreas-islet.html.

About Matt Wood (336 Articles)
Matt Wood is the editor of the Science Life blog and the social media specialist for the University of Chicago Medicine.
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