Fat molecule cardiolipin functions like an "on-off switch" for the activity of our brown fat, a new study conducted at the University of Copenhagen shows. Brown fat is a fascinating and unique type of fat tissue that actually burns calories rather than stores them.
Switching off production of cardiolipin in mice leads to insulin resistance, which is the cornerstone of diabetes, says Associate Professor Zach Gerhart-Hines from the Novo Nordisk Foundation Center for Basic Metabolic Research and senior author of the study.
Burn More Calories
- We generated mouse models in which we could switch off cardiolipin production in brown fat. After decreasing cardiolipin levels, the mice became insulin resistant and thus provided a clear link to diabetes. What really surprised us was that when we turned up the production of cardiolipin in both mouse and human fat cells, we increased the amount of calories the fat cells were able to burn, Zach Gerhart-Hines explains.
Conclusions Supported by Human Genetics and Diabetic Patients
The researchers further uncovered promising evidence that strongly suggests the scientific findings are relevant to humans.
When the researchers investigated the genetics of metabolic disease, they found that people with a gene mutation linked to low cardiolipin production have a higher risk of being overweight and developing type 2 diabetes than others.
The researchers also examined the levels of the enzyme that makes cardiolipin in fat cells from healthy and diabetic patients. They found that fat cells from healthy, insulin-sensitive people had significantly more cardiolipin-producing enzyme.
"We're excited that what we find in the petri dish and animal models seems to also be true in humans. This could open up new approaches to improve metabolic health by finding ways to boost the amount of cardiolipin in the body's fat cells, says Elahu Sustarsic, the postdoctoral researcher at the University of Copenhagen who led the studies.
Boosting Brown Fat Power in the Future
This work has revealed for the first time that a single fat molecule in the powerhouse of fat cells can have a profound influence on the health of the whole body. The researchers now hope to uncover ways to boost cardiolipin in fat cells to increase insulin sensitivity and combat metabolic disease.
The highly collaborative effort is the result of several research groups' cross-disciplinary exploration of the brown fat cells' production of cardiolipin. Researchers from Harvard Medical School in the US, the Helmholtz Diabetes Center in Germany, and several Danish institutions including the University of Southern Denmark and University of Copenhagen have contributed to the project.