Drug Reverses Diabetes in Animals
By Daniel DeNoon
Jan. 18, 2002 — A drug that cures diabetes in lab animals finally has begun human tests. The radical idea behind the drug — still unproven — is that a person’s body can rebuild its own broken-down insulin factories.
The drug doesn’t even have a catchy name yet. Its inventors — Lawrence Rosenberg, MD, PhD, of Canada’s McGill University and Aaron I. Vinik, MD, of East Virginia Medical School, Norfolk — call it INGAP peptide. It stands for islets neogenesis-associated protein. Its exact meaning is still unclear.
People with diabetes need insulin when their own insulin-making cells die off. These cells, called beta cells or islet cells, live in the pancreas. The new drug is a chemical messenger that tells normal pancreas cells to turn into islet cells.
“If we could regenerate insulin-producing cells, in theory it would mean that patients would not have to take insulin,” Rosenberg tells Web. “We need to know if these cells, too, will die off. We don’t have any hard evidence that this will or will not happen.”
The discovery of INGAP began accidentally. Working to develop a laboratory model of pancreas disease, Rosenberg and Vinik wrapped an animal pancreas in cellophane. To their surprise, the isolated pancreas began to grow new islet cells. Further research showed that this happened because the pancreas was making INGAP. Later studies showed that only a small portion of INGAP — INGAP peptide — was needed to stimulate growth of new islet cells. Eventually, the researchers discovered the INGAP gene and learned how to make large quantities of the INGAP peptide.
What appears to happen is that the pancreas has a large reservoir of cells that act like stem cells. When they get the right signal, they turn into insulin-making islet cells.
“This is an area of active and potentially very fruitful investigation,” diabetes expert Leann Olansky, MD, tells WebMD. Olansky, an endocrinologist at the University of Oklahoma, says that several different research teams are working to develop agents that stimulate the growth of new islet cells.
Just making new islet cells might not be enough. The cells still have to act right. They must make insulin when — and only when — the powerful hormone is needed.
This seems to happen. Animals with diabetes-like disease had increased insulin production and lower sugar levels in the blood after a single dose of INGAP peptide.
Even if the new islet cells work, they have to survive. The worry is that whatever killed off the original islet cells will kill the new cells, too. But this doesn’t seem to happen in the case of islet cells transplanted from an organ donor.
Currently, a major clinical study is exploring the use of islet-cell transplants to treat diabetes. Such transplants could result in a cure — but there’s a big problem. It takes two donors to provide enough islet cells for a single transplant. Only 3,000 donor organs become available each year. There are some 800,000 people with type 1 diabetes.
“The issues surrounding islet transplant are very complex, and the downside is there just aren’t enough donors and never will be,” Rosenberg says. “The next generation approach will be stem cells, where you could grow your own islets outside the body. The problem is you have to have a source of stem cells. For the foreseeable future, that is not a viable alternative either. The advantage of our approach is that we can generate stem cells so that everything happens in the person’s body. We only kick start the process and the body takes care of the rest. That is the beauty of it.”
The initial human study will test the safety of INGAP peptide. A planned 62 patients with type 1 or type 2 diabetes will receive increasing doses. The trial is taking place at three medical centers: the University of Texas Health Science Center, San Antonio; the University of North Carolina, Chapel Hill; and the MedStar Research Institute, Washington, D.C.
INGAP peptide is patented by the two universities and licensed to GMP Companies Inc., Ft. Lauderdale, Fla. An earlier licensing agreement with Eli Lilly and Company expired, Rosenberg says.
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