Changing fat from white to brown

The removal of one single gene in our fat cells could be the key to a new obesity treatment where scientists could make fat cells burn energy instead of accumulating it.

New experiments with mice show that it is possible to treat obesity by changing the fat cells of the body. US scientists from the University of Massachusetts used the CRISPR method that can remove specific genes from genetic material to make the discovery.

Body fat exists in two variants: white and brown. In white fat, cells function as passive energy storage, whereas brown fat cells actively boost fat burning, converting the fat into heat. Babies have plenty of brown fat cells, allowing them to quickly heat their bodies, but the number is reduced as we grow older.

The new method can change this. The scientists extracted white fat cells from people, removing a gene by the name of NRIP1. Without this gene the cells developed into brown fat cells, which the scientists subsequently injected into lab mice. The scientists put the mice on a fattening diet to see the effect compared with other mice with ordinary white fat cells.

The results showed that the mice with brown fat only gained half as much weight as the mice with white fat. Moreover, the mice with brown fat continued to have normal blood sugar regulation and normal sensitivity to insulin. The mice with white fat, however, developed symptoms of diabetes with poor blood sugar regulation.

Studies of the mice livers also revealed that the mice with brown fat had normal brown livers, whereas those with white fat had developed enlarged and pale livers.

The scientists are now going to test the method on monkeys before trials involving humans can begin.