In a discovery that has stunned even those behind it, scientists at a Toronto hospital say they have proof the body’s nervous system helps trigger diabetes, opening the door to a potential near-cure of the disease that affects millions of Canadians.
The problems stem partly from inflammation — and eventual death — of insulin-producing islet cells in the pancreas.
Dr. Dosch had concluded in a 1999 paper that there were surprising similarities between diabetes and multiple sclerosis, a central nervous system disease. His interest was also piqued by the presence around the insulin-producing islets of an “enormous” number of nerves, pain neurons primarily used to signal the brain that tissue has been damaged.
Suspecting a link between the nerves and diabetes, he and Dr. Salter used an old experimental trick — injecting capsaicin, the active ingredient in hot chili peppers, to kill the pancreatic sensory nerves in mice that had an equivalent of Type 1 diabetes.
It turns out the nerves secrete neuropeptides that are instrumental in the proper functioning of the islets. Further study by the team, which also involved the University of Calgary and the Jackson Laboratory in Maine, found that the nerves in diabetic mice were releasing too little of the neuropeptides, resulting in a “vicious cycle” of stress on the islets.
Their conclusions upset conventional wisdom that Type 1 diabetes, the most serious form of the illness that typically first appears in childhood, was solely caused by auto-immune responses — the body’s immune system turning on itself.
They also conclude that there are far more similarities than previously thought between Type 1 and Type 2 diabetes, and that nerves likely play a role in other chronic inflammatory conditions, such as asthma and Crohn’s disease.
So next they injected the neuropeptide “substance P” in the pancreases of diabetic mice, a demanding task given the tiny size of the rodent organs. The results were dramatic.
The islet inflammation cleared up and the diabetes was gone. Some have remained in that state for as long as four months, with just one injection.
The researchers are now setting out to confirm that the connection between sensory nerves and diabetes holds true in humans. If it does, they will see if their treatments have the same effects on people as they did on mice.
About two million Canadians suffer from diabetes, 10% of them with Type 1, contributing to 41,000 deaths a year.
Diabetes effects 230 million people worldwide Diabetes accounts for 5% to 10% of most nations’ health budgets. There are 6 million new diabetes sufferers in the world each year. Every ten seconds someone in the world dies as a result of having diabetes – 3 million deaths a year. Diabetes causes more cases of blindness and visual impairments in adults than any other illness in the developed world. One million amputations each year are caused by diabetes. A diabetes sufferer is up to 40 times more likely to need a lower-limb amputation when compared to a person who does not have diabetes.