A team of researchers at the Perelman School of Medicine at the University of Pennsylvania has discovered that obese mice, treated with the cytokine (a category of proteins) known as TSLP, reported significant fat and weight loss. Described as an “unforeseen finding,” researchers also said that the fat loss was in no way related to decreased food intake or faster metabolism. The treatment revealed, “TSLP prompted the immune system to release lipids through the skin’s oil-producing sebaceous glands.” 

The study is led by Taku Kambayashi, Associate Professor of Pathology and Laboratory Medicine at the University of Pennsylvania. He was joined by Ruth Choa, a fourth-year PhD medical student. Kambayashi said that despite being an unexpected discovery, the team has demonstrated that fat loss was possible by secreting calories from the skin in the form of energy-rich sebum. The professor added that the findings of the animal experiment also show that this could develop into a model for the treatment of obesity among people.  

Kambayashi said that they never thought the TSLP would have any impact on obesity itself. What they set out for was to find out if it impacted insulin resistance. “We thought that the cytokine could correct Type 2 diabetes, without actually causing the mice to lose any weight,” he said.

In order to see the effect of TSLP on Type 2 diabetes, the researchers administered on obese mice a viral vector to increase their bodies’ TSLP levels. Four weeks after the mice were administered injections, the team found that TSLP, besides affecting their diabetes risk, also reduced obesity in them. Compared to TSLP-treated mice, the control group continued to gain weight. The TSLP-treated mice lost 20 grams, going from 45 to just 25 grams in 28 days, the team said. 

Not just that, while the mice reported weight and fat loss, Kambayashi assumed that TSLP was perhaps sickening them. Upon further testing, the group realised that the mice receiving TSLP treatment were also eating 20 to 30 percent more. Besides, they also had similar energy expenditures, base metabolic rates, and activity levels compared to their non-treated counterparts.

Could this work on Humans?

The authors of the study said that in humans, shifting sebum release into “high gear” could feasibly lead to the “sweating of fat” and weight loss.

Kambayashi’s group next plans to test this hypothesis. He said that he doesn’t think humans naturally control their weight by regulating sebum production. “We may be able to hijack the process and increase sebum production to cause fat loss,” he said.