A team of researchers from UC San Francisco was able to isolate beige energy burning fat from humans. This type of fat is known to convert unhealthy white fat into healthy brown fat. In their study, “Genetic and functional characterization of clonally derived adult human brown adipocytes,” recently published in Nature Medicine, the researchers were also able to identify these beige fat genetic markers.

According to Shingo Kajimura, PhD, assistant professor of cell and tissue biology at UCSF, who collaborated with the UCSF Diabetes Center and the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF, said that these new findings are vital for the development of new drugs to fight obesity.

Humans have two types of fat: the white variant, whose function is to store energy is associated with obesity and diabetes, and the brown fat variant that creates heat by energy burning, which is linked to leanness. Human babies are born with brown fat as a natural protection against cold.

Previous evidence indicates that adult humans also have brown fat in the body, however, it remained unclear if this fat is the classic brown fat or a beige type, which has the ability to convert white fat into brown fat in response to cold.

To address this, the research team isolated and replicated single brown fat cells from two adult individuals. Following high-tech genetic and protein samples of the duplicated cells, the team determined that they had effectively isolated brown fat.

“This finding brings us another step closer to the goal of our laboratory, which is engineering fat cells to fight obesity,” said Kajimura in a news release. “We are trying to learn how to convert white fat into brown fat, and until now, it had not been demonstrated that this recruitable form of brown fat is actually present in humans.”

Now Kajimura’s research team can use the beige fat cell culture system as a screening platform able to detect and test small molecules responsible for the development, differentiation and thermogenic activity of brown fat. The research team aims to develop drugs able to transform white fat in brown fat.

“If you think about obesity, it’s generally caused by an imbalance between energy intake and energy expenditure,” Kajimura said in the news release. “So far, all of the approved anti-obesity medications reduce energy intake by decreasing appetite. They work in the short term, but they often have side effects such as depression. If we have a compound that increases energy expenditure by recruiting new brown fat and activating brown fat thermogenesis, then it might work synergistically with conventional anti-obesity medications. This would be a novel approach to modulating whole-body energy balance.”