Type 1 Diabetes May Be Caused By Disruption of Link Between Nerve Cells and Beta Cells

New York, NY, December 15, 2006 — Researchers in Canada have found evidence in mice that the autoimmune attack causing type 1 diabetes may be triggered by abnormal nerve endings in the pancreatic beta cells. The scientists found that in mice that usually develop type 1 diabetes spontaneously, removing these defective nerve endings prevented the mice from contracting the disease. The study was led by Hans Michael Dosch, a scientist at the Hospital for Sick Children in Toronto, and published in the latest issue of the journal Cell.The researchers identified a “control circuit” between islet cells and the sensory nerves surrounding them. The nerve cells normally produce a neuron-peptide that keeps this circuit functioning. But since defective neurons can’t produce the substance, the circuit is disrupted. This led to inflammation around the islets and eventually to their destruction—and type 1 diabetes in the mice. Conversely, the researchers found that infusing the animals with the neuron-peptide actually reversed early diabetes.This is an intriguing finding that could lead to increased focus on the role nerve cells play in the initiation of type 1 diabetes. It has long been assumed that the misguided autoimmune attack that causes type 1 diabetes is aimed at pancreatic beta cells from the very beginning. But the new findings suggest that the connection between nerve cells and beta cells is where the disease process begins. (The new research is preliminary and was conducted in mice, so it is far from certain whether human type 1 diabetes is triggered by the same events.)If research in humans supports these findings, it could provide a possible new therapeutic target for diabetes prevention and a strategy for diagnostic tests to detect diabetes risk earlier. It also could offer a way to produce conditions that allow beta cell regeneration. And it would shed light on a possible link between type 1 diabetes and autoimmune attacks on nervous tissue.Although JDRF did not fund the new study in Cell, it supported earlier research by Dr. Dosch into a possible connection between nerve cells and type 1 diabetes. In 2003, Dr. Dosch and colleagues found that the autoimmune destruction in type 1 diabetes was not limited to beta cells, but destroyed nerve cells as well. JDRF funded that research, which was published in Nature Medicine, and the human islets used were provided by a JDRF research center in Pittsburgh.