For Diabetics, Insulin Transplants Increasingly an Option
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Diabetes sufferers have reason to take heart. An experimental procedure introduced in clinical trials a few years ago is looking increasingly promising to not only manage the disease, but to cure it. While the availability of the treatment is not widespread in the United States, and is still considered in a testing phase here, in March researchers in Melbourne, Australia successfully performed the procedure, transplanting insulin-producing cells into a 54-year-old patient suffering from type-1 diabetes.

Type-1 diabetes stops the pancreas from producing insulin; patients instead inject the insulin daily. The procedure, known as an islet cell transplant, was conducted at St. Vincent’s Hospital with the patient under local anesthetic, and, using an ultrasound to guide the needle, took insulin-producing cells from a donor pancreas and transfused them into the recipient’s liver.

The 54-year-old woman previously used to inject insulin up to eight times a day. For the first time in 25 years, she is now producing her own insulin. Still, a second transfusion would likely be required before the woman would no longer need insulin injections. Yet the head of the transplant program at St. Vincent’s, Dr. Tom Kay, reported that she is only now taking a very small does of insulin, five units daily. An islet cell transplant may be an option for you if you have complications from type-1 diabetes or severe type-1 diabetes that can't be effectively managed with insulin.

How does the pancreas lose its ability to produce insulin? The pancreas releases enzymes into your small intestine to break down nutrients. It also releases hormones into your bloodstream to help your body use glucose, one of the cells’ main sources of energy. One of these hormones, insulin, lets glucose enter your cells. Throughout the pancreas are clusters of specialized cells that produce insulin. When you have type-1 diabetes, your immune system attacks and kills these cells. This may occur through a combination of factors, including a genetic predisposition or exposure to certain viruses.

Without insulin, glucose can't get into your cells. Lack of insulin can lead to potentially fatal complications. High blood sugar, which can eventually damage your blood vessels and other tissues, is a particular concern. Your eyes, nerves, and kidneys are particularly susceptible to this damage.

The transfusion of insulin-producing cells represents an important breakthrough in the way we treat type-1 diabetes. But researchers admit that two obstacles still need to be overcome to ensure the future success of the program: a diminished supply of pancreas donors and the fact that recipients must take anti-rejection drugs. Until the body accepts the insulin, patients need to take medications that suppress the immune system. Side effects from these drugs may include mouth sores, acne, diarrhea, nausea, vomiting, and fatigue. Patients are more susceptible to viral and bacterial infections. Other serious concerns include increased blood cholesterol levels, high blood pressure, decreased kidney function, and an increased risk of tumors and certain types of cancer.

The procedure, too, only works on type-1 diabetes patients as of now. Type-2 diabetes is far more common, affecting over 19 million people. In type-2 diabetes, the pancreas produces insulin, but the body can't use it very well. An insulin deficiency or resistance characterizes type-2 diabetes. The disease is associated with older age, obesity, family history of diabetes, and physical inactivity. Symptoms develop gradually and are often overlooked. The Centers for Disease Control and Prevention (CDC) estimate that nearly 30% of people with type-2 diabetes are undiagnosed.

If you live in the United States, where islet cell transplants are considered experimental, getting one usually means participating in a clinical trial and waiting for a donor pancreas. An islet cell transplant begins in a lab, where technicians extract and purify islet cells from a donor pancreas. Often, two or more donor organs are needed to accumulate enough islet cells for a single complete transplant. The lack of suitable donor pancreases is a major obstacle in the widespread use of islet cell transplants.

In a study of 36 islet cell transplant recipients published in 2006, more than 40% of participants were off insulin therapy completely within one year of the last infusion of islet cells. In a study of 65 islet cell transplant recipients published in 2005, only 10 percent of participants remained off insulin therapy five years after the last infusion of islet cells. Many participants were able to use less insulin than before the transplant, however, and maintain better control of their blood sugar.

But success can be measured in various ways. Even if an islet cell transplant doesn't lead to long-term blood sugar control, severe insulin reactions are less likely after the procedure. Despite bumps in the road right now, the procedure is clearly a step toward one day finding a cure for diabetes, as opposed to simply managing it.

MayoClinic.com, Sept. 28, 2007, “Islet Cell Transplant: Experimental Treatment for Type-1 Diabetes,” http://www.mayoclinic.com/health/islet-cell-transplant/DA00046;

Herald Sun, Australia, March 19, 2008, “Local Diabetes Breakthrough Hailed,” by Georgie Pilcher, http://www.news.com.au/heraldsun/story/0,21985,23402701-24331,00.html;

Centers for Disease Control and Prevention, 2005, “National Diabetes Fact Sheet,” http://www.cdc.gov/diabetes/pubs/factsheet.htm;

U.S. Dept. Health and Human Services, 2006, “Diabetes Prevention Program” (NIH Publication No. 06-5099), http://diabetes.niddk.nih.gov/dm/pubs/preventionprogram

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