In a major step towards engineering healthy fat cells as a novel measure to fight obesity, researchers have identified energy-burning "beige" fat in humans, which is known to be able to convert unhealthy white fat into healthy brown fat.
The finding published online in the journal Nature Medicine could lead to new anti-obesity drugs that could increase energy expenditure in the body by turning white fat into brown fat through "beige" fat or what they call recruitable brown fat.
"The discovery is an important advance in the search for new medications to fight obesity," said senior investigator Shingo Kajimura, assistant professor at the University of California, San Francisco.
All mammals, including humans, have two types of fat with completely opposite functions: white, which stores energy and is linked with diabetes and obesity, and brown, which produces heat by burning energy and is associated with leanness.
Beige fat is found within white fat and has the ability to convert, or recruit, white fat into brown fat in response to cold or other stresses.
However, until now, "it had not been demonstrated that this recruitable form of brown fat is actually present in humans," Kajimura noted.
For the study, the researchers isolated and cloned single brown fat cells from two adult individuals.
After sophisticated genetic and protein analyses of the cloned cells, they concluded that they had successfully isolated recruitable brown fat.
Now that they have a reliable human beige fat cell culture system, Kajimura said, his team would be able to use the system as a screening platform to identify and test small molecules that activate the development, differentiation and thermogenic (heat-producing) activity of human brown fat.
The ultimate aim, he said, is the creation of drugs to turn white fat into brown fat through brown fat recruitment.
