New Plan May Reverse Type 1 Diabetes
Promising Results Seen in Tests on Mice; Human Studies Not Yet Done
April 20, 2006 -- Scientists have used a two-pronged treatment to reverse recent-onset type 1 diabetesdiabetes in mice.
The approach hasn't yet been tested on humans, but the results from tests on mice are "encouraging," the researchers write in The Journal of Clinical Immunology.
Damien Bresson, PhD, and Matthias von Herrath, MD, were among the experts who worked on the study. They work at California's La Jolla Institute for Allergy and Immunology.
In a news release, von Herrath mentions a "strong synergy" between the two treatments that were tested on the mice. Combining the two treatments "doubled the efficacy in laboratory mice -- with fewer side effects than using either one alone," von Herrath says.
In type 1 diabetes, the body's immune system attacks cells in the pancreas that make insulin -- a hormone that controls blood sugar. As a result, the pancreas makes little or no insulin, and patients must take insulin daily.
Nearly 20 million people worldwide have type 1 diabetes, according statistics cited in the new study. Type 2 diabetes is much more common. In type 2 diabetes, the body usually makes enough insulin but it doesn't respond to insulin properly.
Type 1 diabetes typically starts in children or young adults, but can appear at any age. Symptoms include increased thirst and urination, hunger, weight lossweight loss, blurred vision, and extreme fatiguefatigue. If not diagnosed and treated with insulin, a person with type 1 diabetes can lapse into a life-threatening diabetic coma.
The new study included mice that had recently developed type 1 diabetes. The researchers had two goals: Coax the mice's immune systems to stop attacking insulin-making pancreatic cells and boost insulin production.
To calm the mice's immune systems, the scientists gave the mice oral doses of antibodies that targeted certain immune system cells, called T cells, that are involved in attacking pancreatic cells in type 1 diabetes.
By sidelining those T cells, the antibodies also promoted another type of cell, called regulatory T cells (T-regs), which ordered the immune system to leave the pancreatic cells alone. In short, the antibodies spurred the immune system to hold its fire against the pancreatic cells.
The cease-fire was just the starting point. The researchers gave the mice intranasal doses of a peptide (a building block of protein) that boosted protection of the insulin-producing pancreatic cells.
Reversing Type 1 Diabetes in Mice
Those two treatments were more effective together than they were apart, the study shows.
"When administered in combination, the efficacy strikingly increased," the researchers write. They note long-term reversal -- lasting at least nine weeks -- in two different models of mice with type 1 diabetes. Roughly half of the mice experienced that remission, the study shows.
The findings might be "highly relevant" in setting the stage for human tests, the researchers write. They add that the risk of side effects should be lower by combining the two treatments instead of using them separately.