'Brown fat' could hold the answer to obesity epidemic

Published on Wednesday 29 July 2009 20:40

SUGAR-BURNING "brown" fat could in future be manufactured in the body to tackle obesity, it has been claimed.

Scientists have discovered a biochemical switch that triggers the creation of brown fat, which is normally present in newborn babies, but almost absent in adults.

They hope to find ways of using the switch to promote production of the weight-loss tissue in obese people.

Unlike "white" adipose fat, brown fat contains large numbers of mitochondria – tiny biological power plants that burn sugar from food to provide energy for cells.

Researchers in the US found that two proteins called PRDM16 and C/EBP-beta worked together to turn other types of cells into brown fat cells.

Using this "switch", the researchers created fully functional human and mouse brown fat cells in the laboratory.

After the cells were transplanted into living mice, they were found to burn calories at a rapid rate. The same energy would otherwise have been stored as white adipose fat.

The scientists, who reported their research in the journal Nature, called the artificially made cells eBAT cells (engineered Brown Adipose Tissue).

Dr Shingo Kajimura, of the Dana-Farber Cancer Institute in Boston, said: "Since brown fat cells have very high capacity to dissipate excess energy and counteract obesity, eBAT has a very high potential for treating obesity."

Viruses were used to transfer genes for the switch proteins into embryonic mouse skin cells. The switch was also installed into adult mouse skin cells and human skin cells taken from newborn babies.

In all three cases, the cells were transformed into working brown fat cells. Scans showed they burned up excess energy after being transplanted into mice.