Issue 151 Item 1 Protein in Wheat Plays A Role in Promoting Type 1Diabetes

Researchers have identified a protein in wheat called Glb1 which may play a role in the development of type 1 diabetes. Researchers investigating type 1 diabetes agree that the disease develops through the interaction of genes and one or more environment triggers. Although many theories have been proposed suggesting that exposure to dietary proteins may trigger the immune system attack leading to type 1 diabetes, studies attempting to establish such links until now have produced negative or contradictory results

The research, funded partly by JDRF, sheds light on autoimmune responses set into motion by certain dietary components. It also raises the possibility that exposing children to Glb1 at a young age could teach the immune system not to overreact when exposed to the protein at a later time.

The gastrointestinal tract is lined with large numbers of immune cells that defend against potentially harmful microbes.In animal models of type 1 diabetes, researchers have found inflammation in this tissue that resembles inflammation found in the pancreas of animals (and people) developing type 1 diabetes. In addition, patients with type 1 diabetes are at

an increased risk for another autoimmune affliction involving the gastrointestinal tract:

Celiac disease occurs when immune cells in the gut react to a certain protein, called gluten, proteins found in wheat, rye, and barley. Once aroused, the immune cells attack and damage the lining of the intestine making it difficult to absorb nutrients from foods. Although rare in the general population, celiac disease occurs more frequently in people with type 1 diabetes (with estimates ranging from 2 – 16 percent). The fact that people with type 1 diabetes have celiac disease at a much higher rate than the general population suggests that some people that share common risk genes may be particularly sensitive to wheat and could develop a misguided immune response to certain foods.

Dr. Scott began testing various diets in diabetes-prone rodents. His goal was to identify specific food proteins that promoted development of diabetes and to understand the mechanisms by which this occurs.

Dr. Scott identified wheat proteins as a prime candidate because wheat-based diets resulted in high diabetes incidence in animal models of diabetes. Scott and his colleagues proposed that one or more wheat proteins were spurring the gastrointestinal immune cells into action, and once aroused, the cells were targeting pancreatic islets and causing type 1 diabetes.

Dr. Scott and his colleagues scanned through one million candidate proteins from wheat, eventually narrowing the field to three that cause reaction in the immune system, and then finally to Glb1, which is associated with damage in the pancreatic islets. The researchers took blood from people with type 1 diabetes and a rat model for the disease and exposed it to Glb1. Antibodies in the blood reacted strongly to Glb1, suggesting it plays some role in triggering the autoimmune attack that causes diabetes. The results from the study were selected as the cover illustration for the January 3 issue of the Journal of Biological Chemistry.

The researchers have also shown that exposing diabetes-prone animals to wheat proteins in infancy can delay and protect some diabetes-prone animals from the disease possibly by teaching the developing immune system not to overreact if it encounters these proteins later in life. This work was published in the January 2002 issue of More Information