Type 1 Diabetes Progenitor Caught In The Act

Immune cells long thought to be the progenitor of type 1 diabetes have been isolated and analyzed, and shown to indeed be key in causing this serious disease. This finding could very well lay the foundations for a preventative technique for type 1 diabetes.

The immune cells are known as dendritic cells, and reside in the “islets of Langerhans,” an isolated insulin-producing region of the pancreas. According to the study, these dendritic cells were caught “red-handed,” seen “carrying insulin and fragments of insulin-producing cells known as beta cells.”

Type 1 diabetes, which is also known as juvenile diabetes, develops because “the immune system has destroyed the islets of Langerhans, which contain the body’s only beta cells.” Without these beta cells, pancreatic insulin, which regulates blood sugar levels, is depleted, and insulin injections are required. In America, it’s believed that between one and two million individuals suffer from type 1 diabetes.

Dendritic cells have long been thought to contribute to type 1 diabetes, but isolating them had been a major challenge. “They’re very tiny and there are only about 5 to 10 of them per islet, each of which contains approximately a thousand cells,” says senior study author Dr. Emil R. Unanue.

Dr. Boris Calderon, a researcher and one of the study authors, developed a sophisticated technique to isolate the dendritic cells. After isolating the cells, Dr. Calderon “found indications that the cells were carrying granules of insulin and pieces of proteins from beta cells on their cell surfaces.”

To show that an attack was being made on the actual insulin producing beta cells, subsequently leading to type 1 diabetes, Dr. Calderon “exposed the dendritic cells to lymphocytes taken from diabetic mice. The lymphocytes were activated by the dendritic cells of the islets and switched into attack mode.” Lymphocytes are immune cells responsible for destroying foreign invaders, like viruses and bacteria, but can sometimes be falsely triggered, like in this case where they destroy valuable insulin-producing beta cells.

Finding and observing the likely cause of type 1 diabetes is a huge step in finding ways to treat and prevent the disease. A further understanding of how these dendritic cells function and why they falsely trigger the destruction of pancreatic beta cells is the next step. A further understanding “may allow us to find ways to inhibit dendritic cell function in order to block the disorder [type 1 diabetes],” says Dr. Unanue.

Source: Defeat Diabetes Foundation: Calderon, Boris. Suri, Anish. Miller, Mark. Unanue, Emil. PNAS online. “Dendritic cells in islets of Langerhans constitutively present â cell-derived peptides bound to their class II MHC molecules.” May 2008. Purdy, Michael. Washington University in St. Louis School of Medicine news release. May 2008.