A new weight-loss treatment that makes mice ‘sweat’ out fat has been discovered by scientists — who say it could even be used on humans to tackle obesity.
Researchers found it is possible to induce stomach fat loss by targeting the immune system, although the knock-on effect is greasy hair.
They made the discovery after treating mice with the cytokine thymic stromal lymphopoietin (TSLP) — a type of immune system protein — which led to significant fat and weight loss.
A new weight-loss treatment that makes mice ‘sweat’ out fat has been discovered by scientists — who say it could even be used on humans to tackle obesity (stock image)
Unexpectedly, however, this was not caused by a decreased food intake or faster metabolism, but instead because the TSLP stimulated the immune system to release lipids through the skin’s oil-producing sebaceous glands.
‘This was a completely unforeseen finding, but we’ve demonstrated that fat loss can be achieved by secreting calories from the skin in the form of energy-rich sebum,’ said the study’s lead author Taku Kambayashi, from the University of Pennsylvania.
‘We believe that we are the first group to show a non-hormonal way to induce this process, highlighting an unexpected role for the body’s immune system.’
Kambayashi said the findings support the possibility that increasing sebum production via the immune system could be a strategy for treating obesity in humans.
Researchers were investigating the role of TSLP, which is involved in asthma and other allergic diseases, in activating Type 2 immune cells and expanding T regulatory cells.
Past studies have suggested these cells can regulate energy metabolism, so Kambayashi’s team predicted that giving overweight mice TSLP might stimulate an immune response that would counteract some of the harmful effects of obesity.
‘Initially, we did not think TSLP would have any effect on obesity itself. What we wanted to find out was whether it could impact insulin resistance,’ Kambayashi said.
‘We thought that the cytokine could correct Type 2 diabetes, without actually causing the mice to lose any weight.’
Scientists made the discovery after giving mice the cytokine thymic stromal lymphopoietin — a type of immune system protein — which led to significant fat and weight loss (stock image)
To test the effect of TSLP on Type 2 diabetes, the researchers injected obese mice with a viral vector that would increase their bodies’ TSLP levels.
After four weeks the team found that TSLP had not only affected diabetes risk, but it had actually reversed obesity in the mice, too.
While the control group continued to gain weight, the weight of the TSLP-treated mice went from 45g down to a healthy 25g, on average, in just 28 days.
TSLP-treated mice also saw a decrease in their visceral fat mass — the white fat that is stored in the abdomen around major organs, which can increase diabetes, heart disease and stroke risk.
Kambayashi assumed that the TSLP was making the mice sick and reducing their appetites. However, further testing established that they were actually eating 20 to 30 per cent more when compared to their non-treated counterparts.
It was then that he recalled a small observation he had previously ignored.
‘When I looked at the coats of the TSLP-treated mice, I noticed that they glistened in the light. I always knew exactly which mice had been treated, because they were so much shinier than the others,’ Kambayashi said.
He then wondered whether their greasy hair was a sign that the mice were ‘sweating’ out fat from their skin, a theory the researchers tested by shaving the TSLP-treated mice and the controls and extracting oils from their fur.
They found that the shiny fur contained sebum-specific lipids, proving Kambayashi’s hypothesis correct. Sebum is a calorically-dense substance produced by sebocytes in the sebaceous glands and helps to form the skin barrier.
It confirmed that the release of oil through the skin was responsible for the TSLP-induced fat loss.
Researchers said that in humans shifting sebum release into ‘high gear’ could feasibly lead to the ‘sweating of fat’ and weight loss, which is what they plan to test next.
‘I don’t think we naturally control our weight by regulating sebum production, but we may be able to highjack the process and increase sebum production to cause fat loss,’ Kambayashi said.
‘This could lead to novel therapeutic interventions that reverse obesity and lipid disorders.’
The research was published in the journal Science.