For nearly a century, insulin has been a life-saving diabetes treatment. Now scientists are testing a tantalising question: what if pills containing the same medicine patients inject every day could also prevent the disease?
More than 400 children and adults are participating in U.S. government-funded international research investigating whether experimental insulin capsules can prevent or at least delay Type 1 diabetes. Hospitals in the United States and eight other countries are involved, and recruitment is ongoing.
To enroll, participants must first get bad news: results of a blood test showing their chances for developing the disease are high.
A small, preliminary study by different researchers, published recently in the Journal of the American Medical Association, suggests the approach might work. Children who took insulin pills showed immune system changes that the researchers said might help prevent diabetes. The study was too small and didn't last long enough to know for sure.
The ongoing larger study is more rigorous, randomly assigning participants to get experimental insulin capsules or dummy pills, and should provide a clearer answer.
"Does it prevent indefinitely? Does it slow it down, does it delay diabetes? That also would be a pretty big win," said Dr. Louis Philipson, a University of Chicago diabetes specialist involved in the study.
About 1.25 million Americans have Type 1 diabetes. Type 2 disease is more common, affecting nearly 30 million nationwide and most of the more than 300 million worldwide with diabetes. Besides short-term complications from poorly controlled blood sugar, both types raise long-term risks for damage to the kidneys, heart and eyes.
Both types are increasing, and for Type 2, experts think that's because of rising obesity and inactivity. But the upward trend in Type 1 diabetes, increasing worldwide by at least 3 percent each year, is more perplexing.
In Type 1 diabetes, the pancreas stops making insulin, a blood sugar-regulating hormone that helps the body convert sugar in food into energy. Treatment is lifetime replacement insulin, usually via injections or a small pump. In Type 2, the body can't make proper use of insulin. It can sometimes be treated with a healthy diet and exercise.
Genes are thought to increase risks for Type 1 diabetes. Viruses and other infections are among factors suggested as possible triggers the disease, which causes the body's immune system to attack insulin-producing cells.
Dr. Wendy Brickman, a diabetes specialist at Chicago's Lurie Children's Hospital who's involved in the study, explained that researchers think taking insulin by mouth so that it's digested like food might somehow trick the faulty immune system into not attacking insulin-making cells.
A branch of the National Institutes of Health is funding the prevention research.