Medical researchers on Sunday said they had used over-the-counter allergy drugs to ease Type 2 diabetes in obese mice, in a study that strengthens theories that inflammation plays a role in this disorder.
Harvard Medical School biochemists Guo-Ping Shi and Jian Liu explored a hunch about mast cells, components of the immune system that help to heal damaged tissue, mainly by increasing blood flow to the wound.
In some cases, mast cells accumulate to excessive levels, become unstable and then leak detritus into the surrounding tissue. This results in inflammation and has already been linked with asthma and other allergies.
Shi noted that mast-cell overload also occurred in fatty tissue among people who are obese and diabetic, which prompted him to ask whether diabetes could also be controlled if mast cells were regulated.
In a study published in the journal Nature Medicine, his team tried out two common over-the-counter allergy drugs, ketotifen fumarate and cromolyn, on lab mice that were obese and diabetic.
The rodents were divided into four groups, a control group that was given no special treatment; a group that was shifted to a healthy diet; a third group that kept with its usual diet but was given one of the two drugs; and a fourth, that was given one of the drugs and was also switched to a healthy diet.
Symptoms in the second group improved moderately, the third saw dramatic improvements in both body weight and diabetes, while the fourth recovered by nearly 100 percent in all areas.
The researchers took their investigation a stage further by genetically engineering mice so that their ability to produce mast cells was impaired.
The mice remained slim and non-diabetic, even though they had chomped on a fatty, sugary diet for three months.
"The best thing about these drugs is that we know it's safe for people," Harvard Medical School quoted Shi as saying in a press release. "The remaining question now is: Will this also work for people?"
The team's next step is to try out the drugs on obese and diabetic monkeys.
Three other studies, likewise published in Nature Medicine, explore the role of different immune cells, the so-called T cells, in causing insulin resistance among obese mice.
The work marks a further advance down the avenue of exploration into the immune system as a cause or amplifier of Type 2 or "adult-onset" diabetes, for which metabolism is traditionally fingered as the culprit.