Promising Advances in Islet Cell Transplants for Diabetes
[Writer] This is Research News from U-I-C, the University of Illinois at Chicago.
Today, Dr. Jose Oberholzer, Director of Cell and Pancreas Transplantation talks about promising research that allows severe type 1 diabetes patients to stop taking insulin after a single islet cell transplant.
Here’s Dr. Oberholzer:
[Oberholzer] I have the pleasure to report on our research conducted in juvenile diabetic patients who have received islet transplants to restore their endocrine function and allow them to have a life without insulin. Now diabetes, as you know, is a tremendous problem in the United States. Over 20 million patients affected, and treatment options today are numerous but they are all limited by the inability to control the glucose levels as a normal pancreas would usually do. Now the worst case diabetic patients have what we call juvenile diabetes. It is a diabetes form that occurs very early in childhood or in adolescence and it’s marked by a complete loss of insulin-producing cells in the body of the affected patients.
What we can do today is replace the insulin-producing cells by a transplant, what we call a pancreatic islet transplant, and in successful cases, this allows to take the patients off insulin and allows them to have near-normal glucose levels. Now the major limitation of this today is the limited amount of tissue available and the requirement for using multiple donors to achieve a sufficiently large number of cells that can replace the lost organ function.
Since the year 2000, the so-called Edmonton Protocol, published by Dr. Shapiro from the University of Alberta in Canada has allowed to reproducibly achieve insulin in dependents after an islet transplant so those patients get two, three, sometimes four islet transplants and then can eventually stop taking any insulin shots. Here at the University of Illinois, we were asking the question how we could improve those outcomes and how could we make it possible that patients would receive a single transplant and have the same benefits as after receiving several organs. We investigated the effect of a new drug, exenatide, which is a naturally occurring substance in lizards, and in humans it has the effect of lowering blood sugar levels and allowing the insulin-secreting cells to work just a little bit more efficiently.
This drug was recently approved for clinical use in what we call type 2 diabetic patients, patients who still produce their own insulin, and we thought why not try this in our islet transplant patients and see whether it can make those cells work better. Well the results are certainly encouraging. Since we can show that by using this drug through the classical protocol proposed by the Edmonton Group, we can now achieve insulin independence with one transplant as opposed to two, three or four as before. So we could achieve this in six patients consecutively. Every single patient could stop taking any insulin after a single transplant. This is not so trivial and since we had a transplant in our control group, four patients receiving the classical Edmonton Protocol, we had a transplant up to 1.5 million islets coming from two or three organs.
In the experimental group where we used the exenatide, we could achieve insulin independence with less than half a million islets. Now, unfortunately this drug is not a magic bullet. We had hoped that this drug may allow, over the long term, to increase the functional mass of insulin producing cells and unfortunately, it could not confirm this. Two of the six patients required later on a second transplant to maintain their good islet function and not to have to go back to insulin shots. So if I can summarize the new protocol here at the University of Illinois, using the exenatide allows consistently to achieve insulin independence with only one transplant although at the price that maybe some patients later on will need to have more islet cells. This may seem like a small step but I think it’s an important improvement since it will allow to provide transplants to more patients with the available number of transplants.
Where are we going from there? Currently the National Institute of Health is sponsoring a multi-institutional trial in the United States and we are proud to be part of this and much information can be found on the website of NIH, which is very simple. It’s islet-study-dot-org. A lot of patients can be enrolled there. Again it’s sponsored by the National Institute of Health and strategies such as the use of exenatide is going to be further investigated in larger numbers of patients.
[Writer] Dr. Jose Oberholzer is an associate professor of surgery, endocrinology and bioengineering.
For more information about this research, go to www.today.uic.edu, click on news releases and look for the release dated June 9, 2008.
This has been research news from UIC – the University of Illinois at Chicago.
