Insulin resistance in obese mice is rapidly reversed by killing angry immune cells in fat, researchers have revealed.

According to the researchers, the findings suggest that treatments aimed at specific subsets of the so-called macrophage cells might offer a very effective new antidiabetic therapy.

" We used a genetic 'trick' that allowed us to rapidly kill these macrophages. The treatment killed these cells within hours, and insulin resistance simply reversed itself. It argues strongly that macrophages are causative for the inflammation that leads to diabetes [in those who are obese]," said Jerrold Olefsky of the University of California, San Diego.

Jaap Neels of INSERM in France, who led the work while in Olefsky's lab, added: "The most interesting thing is that this reversal occurs very rapidly. Twenty-four hours later the animals' insulin response had completely normalized. They were still obese, but no longer insulin resistant."

Neels said that the strategy used in the obese mice wouldn't translate to the clinic directly. It's also unclear whether or not it is the same subtype of macrophage cells that invade fat tissue in people who are obese.

However, the findings suggest that you would not necessarily need to target all macrophages to have a beneficial effect on the diseases associated with obesity. That's critical because "you don't want to knock out the whole immune system."

The researchers recently found that a specific subset of macrophages invades obese fat and muscle tissue. Although little was known about them, those macrophages are defined by a CD11c marker expressed on their surfaces.