In the first trial studies of their kind in the United States, diabetes specialists from UC Irvine and Johns Hopkins University have been given approval by the U.S. Food and Drug Administration to surgically implant insulin pumps, UCI officials said Tuesday.
The battery-powered pumps, which can be programmed with a remote-controlled device to emit varying amounts of insulin to control blood sugar, will be implanted in 40 diabetics, said Carol Holleman, nurse practitioner with UCI's diabetes program. Twenty of the pumps are to be implanted by UCI doctors; the other 20 by physicians from Johns Hopkins, of Baltimore, Md.
While three similar kinds of internal pumps are used in Europe, until now only external pumps have been available to American diabetics, she said.
The external pump, usually strapped to the waist, feeds insulin into the body through a tube attached to a needle inserted into the skin. The pump emits a continuous dose of insulin and can be programmed to feed extra amounts to stabilize blood sugar.
The implantable pump is expected to control blood sugar better because it will more closely mimic nature's way of delivering insulin to the body, Holleman said.
"Having a working, implantable pump that is programmable from the outside is at the moment the closest thing to an artificial pancreas," Holleman said.
Diabetes is a disease in which the pancreas does not properly produce insulin, which is necessary to metabolize sugar and other foods. As a result, digested sugars build up in the blood at high levels unless the diabetic takes daily insulin injections.
Even with insulin injections, diabetes can lead to blindness, heart disease, kidney disease and other complications.
About 1.5 million Americans have diabetes and are dependent on insulin injections. The external pump is used by about 12,000 of them, according to Cliff Hague, spokesman for MiniMed Technologies (formerly Pacesetter Systems) of Sylmar, manufacturer of the internal pump to be used in the UCI-Johns Hopkins study.
The internal pump, about the size of a hockey puck, will be implanted under the skin of the lower abdomen, Holleman said. A catheter from the pump will feed insulin to the peritoneum, the membrane that lines the abdomen, where the circulatory system most effectively carries the hormone to the liver. In non-diabetics, insulin is manufactured in the pancreas and then goes to the liver before it is distributed throughout the body.
The internal pump is "more efficient" than the external one, Holleman said. "It mimics normal physiology," which, researchers hope, will lead to better blood-sugar control and fewer complications. It is also more convenient than the external pump, which requires the diabetic to change the tubing and needle every few days, she said.
Implanting the pump is a minor surgical procedure, she said. Once inserted, its outline produces a "lump" under the skin but will not be visible under clothing, she said.
Like the external pump, the internal pump will emit a steady dose to stabilize blood sugar. By holding the remote control device over the abdomen, the dosage can be changed when needed, such as before meals, Holleman said.
It will hold about a two-month supply of insulin, and when it runs dry the diabetic can refill it with a syringe, she said.
During the trial studies, the diabetics will have to test their blood-sugar levels four times a day, she said.
UCI's share of the project will be headed by Dr. Arthur Charles, professor of medicine. He will be assisted by Dr. Jean-Louis Selam, assistant professor of medicine, who arrived in February from Montpelier, France.
Both Charles and Selam were in Europe Tuesday and unavailable for comment.
Until now, one of the major obstacles in the United States to implanting insulin pumps has been that "the people with the most experience are in Europe," Holleman said. Charles recruited Selam because of his reputation as an expert on implantable insulin pumps, she said.
UCI will implant its first pump in December, but the Johns Hopkins team will begin its share about a month earlier, officials said. Holleman said UCI will recruit the first volunteers from among patients currently under treatment in the university's diabetes program. "We would prefer people already using external pumps," she said.
Holleman said two internal insulin devices of a different kind have been implanted in New Mexico and Massachusetts but with limited success. The devices were insulin reservoirs that slowly released insulin, not pumps programmed to feed varying amounts as needed, she said.