Cytokine treated mice lose fat by sweating

Scientists have made an interesting discovery that could lead to treatments for obesity in the future. Researchers discovered that treating mice with a cytokine known as TSLP led to significant abdominal fat loss and weight loss compared to controls in the experiment. The researchers didn't set out to find a potential treatment for fat loss. Rather this was an unintended side effect.Researchers noticed the mice were sweating fat with a seemingly benign observation. Mice treated with TSLP exhibited greasy hair. However, the team says the fat loss wasn't associated with decreased food intake or faster metabolism. Rather, they discovered TSLP stimulated the immune system to release lipids through the skin's oil-producing sebaceous glands.

Principal investigator Taku Kambayashi says the finding was completely unforeseen. The team has demonstrated that fat loss can be achieved by secreting calories from the skin in the form of energy-rich sebum. The team believes they're the first group to show a non-hormonal way to induce this process, highlighting what they call an unexpected role for the immune system.

TSLP, or thymic stromal lymphopoietin, is a type of immune system protein involved in asthma and other allergic diseases. The group was investigating the expanded role of the cytokine to activate Type 2 immune cells and expand T regulatory cells. Previous studies found those cells can regulate energy metabolism, and research predicted treating overweight mice with TSLP could stimulate an immune response, potentially counteracting some of the harmful effects of obesity.

The team didn't expect TSLP to have an impact on obesity itself. Rather, they wanted to determine if TSLP could impact insulin resistance. Their goal initially was to correct Type 2 diabetes without causing the mice to lose weight. While more research is needed, the authors believe this discovery could potentially lead to "sweating fat" and weight loss in humans.