#sugars

Discovery of new metabolic pathway for stored sugars helps explain how cellular energy is produced and expended in obesity, advancing therapeutic potential

Humans carry around with them, often abundantly so, at least two kinds of fat tissue: white and brown. White fat cells are essentially inert containers for energy stored in the form of a single large, oily droplet. Brown fat cells are more complex, containing multiple, smaller droplets intermixed with dark-colored mitochondria — cellular organelles that give them their color and are the “engines” that convert the lipid droplets into heat and energy.

Some people also have “beige” fat cells, brown-like cells residing within white fat that can be activated to burn energy.

In recent years, there has been much effort to find ways to increase brown or beige fat cell activity, to induce fat cells, known as adipocytes, to burn energy and generate heat in a process called thermogenesis as a means to treat obesity, type 2 diabetes and other conditions.

But the therapeutic potential of brown fat — and perhaps beige fat cells —has been stymied by the complexity of the processes involved. It wasn’t until 2009 that the existence of active brown fat cells in healthy adults was confirmed; previously it was believed they were common only in newborns.

In a new study, published online October 27, 2021 in Nature, an international team of researchers led by senior author Alan Saltiel, PhD, director of the Institute for Diabetes and Metabolic Health at University of California San Diego School of Medicine, describe how energy expenditure and heat production are regulated in obesity through a previously unknown cellular pathway.

Image: Artistic rendering of a brown fat cell with nucleus in pink, mitochondria in purple and yellow lipid droplets scattered throughout. Image courtesy of Scientific Animations. 

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