Finding a better way for diabetics
For diabetics, maintaining near-normal blood sugar levels is crucial. Such control reduces complications -- blindness, amputations, organ damage, heart disease and strokes -- and increases life expectancy.
But managing the disease is difficult, often requiring repeated blood tests, daily insulin injections and, despite patients’ best efforts, attempts to quickly stem or raise sugar levels. An experimental device now being tested in the U.S. and Europe could make these herculean monitoring measures a thing of the past -- and eventually make diabetes an easily managed disease.
“This device would be a real breakthrough and give patients with Type 1 diabetes much tighter control of their insulin levels,” says Dr. Francine R. Kaufman, president of the American Diabetes Assn.
Type 1 diabetes, which is the more severe form of diabetes and afflicts about 1 million Americans, occurs when the pancreas produces little or no insulin, a hormone that metabolizes sugar and supplies energy to the cells. Without an adequate supply of insulin, a person is unable to keep blood sugar levels in balance.
The prototype device, the Long-Term Sensor System, mimics the action of the human pancreas by continuously delivering insulin and maintaining blood sugar, or glucose, at a constant level. It consists of two components: One is an insulin pump, which contains a two- to three-month supply of insulin and which is inserted surgically in the fatty tissue above the abdominal muscles. The other is a glucose sensor, which is implanted in a vein near the heart.
“The accuracy of the sensor and the precision of the pump have been proven,” says Dr. Nancy Rikalo, a diabetes specialist at the Sansum Medical Research Institute in Santa Barbara, where the device is being tested. “The remaining hurdle is showing these devices can work together.”
Early tests have been encouraging. In a 2001 study in France, five patients were given the system. For six months, glucose readings taken by the sensors were compared with the results of at least six daily finger-stick tests. When the sensors were demonstrated to be accurate, the next step was taken: For a two-day period, the sensors and the pumps were hooked up, and patients’ insulin levels were controlled by the sensor.
Glucose levels of the patients were maintained in near-normal ranges 42.3% of the time, as compared with 21.6% for patients whose insulin requirements were determined by finger sticks, says Dr. Eric Renard, the study’s lead investigator and an endocrinologist in Montpellier, France.
The device has been implanted in 14 additional patients in France, and six in Santa Barbara, where scientists are awaiting permission from the U.S. Food and Drug Administration to test the system. “We hope to flip the switch sometime this summer,” says Dr. Lois Jovanovic, an endocrinologist at Sansum.
Still, several more years of testing are needed. Medtronic MiniMed, which makes the system, plans to apply for FDA approval for the pump this year, for the internal sensor within two years, and for the system by 2007.
“It will be phenomenal when they put the two components together,” says Kaufman, who is also a pediatric endocrinologist at Childrens Hospital Los Angeles. “When that day comes, we won’t be a medical center -- we’ll be more like Jiffy Lube.”
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Pancreatic cell transplants
Diabetics may also benefit from another new procedure -- a technique, known as the Edmonton Protocol, to transplant insulin-producing islet cells.
Previous attempts to transplant islet cells, which are cells in the pancreas that secrete insulin, rarely worked, and only 10% to 15% of diabetics benefited.
However, Canadian researchers discovered that using a unique combination of anti-rejection drugs boosted success rates dramatically. About three-quarters of the estimated 200 patients who have received transplants haven’t needed insulin injections for at least a year.
The procedure is being tested at 10 U.S. centers. Still, experts say that because of the shortage of donor pancreases, only a couple of thousand people a year could benefit from this procedure.
“Its application is very limited,” says Dr. Francine Kaufman of the American Diabetes Assn.
