The US National Institutes of Health has started an international study of the use of oral insulin to prevent or delay type 1 diabetes.
Type 1 Diabetes TrialNet, an NIH-funded network of researchers dedicated to the understanding, prevention, and early treatment of type 1 diabetes, is conducting the study in more than 100 medical centers across the United States, Canada, Europe, and Australia.
?Our goal is to prevent type 1 diabetes or to delay it as long as possible. If diabetes can be delayed, even for several years, those at risk will be spared the difficult challenges of controlling glucose and the development of complications for that much longer,? said TrialNet study chair Jay Skyler, M.D., of the University of Miami.
In the study, researchers are testing whether an insulin capsule taken by mouth once a day can prevent or delay diabetes in a specific group of people at risk for type 1 diabetes. An earlier trial suggested that oral insulin might delay type 1 diabetes for about four years in some people with autoantibodies to insulin in their blood. Animal studies have also suggested that insulin taken orally may prevent type 1 diabetes. Some scientists think that introducing insulin via the digestive tract induces tolerance, or a quieting of the immune system. Insulin taken orally has no side effects because the digestive system breaks it down quickly. To lower blood glucose, insulin must be injected or administered by an insulin pump.
In type 1 diabetes, a person?s own immune cells destroy the beta cells of the pancreas. Beta cells sense blood glucose and produce the hormone insulin, which regulates glucose and converts it to energy. The immune attack on beta cells begins well before a person develops diabetes and continues long after the disease is diagnosed. In the early stages of autoimmunity, up to 10 years before diabetes is diagnosed, autoantibodies may appear in the blood. These autoantibodies to glutamate decarboxylase (GAD), IA-2, and to insulin itself indicate a greater risk for developing type 1 diabetes. For a person with high-risk genes and all three antibodies, the risk of developing diabetes in the next 5 years is greater than 50 percent.
First- and second-degree relatives of people with type 1 diabetes who may be at risk are being screened through TrialNet?s natural history study, which is examining the immune and metabolic events that precede diabetes symptoms. Screening involves a simple blood test for the autoantibodies that signify diabetes risk. Individuals enrolled in the natural history study are closely monitored for diabetes development and may be eligible to participate in the oral insulin trial or future studies that try to arrest the autoimmune process.