A lot can be learned by understanding the molecular biology of how our fat cells use nutrients. For instance, it can reveal why people with diabetes and obesity have problems in fat cell metabolism and help develop new treatments for their conditions.

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Mature fat cells. Red shows fat droplets that accumulate with the fat cells. The researchers found that the mature fat cells appear to produce fatty acids, in part, from essential amino acids rather than sugar only.
Image credit: UCSD/Metabolic Systems Biology

Now, a new study from the University of California-San Diego (UCSD) and published in the journal Nature Chemical Biology offers fresh clues about which nutrients fat cells process to make fatty acids.

Senior author Christian Metallo, a bioengineering professor in UCSD’s Jacobs School of Engineering, says that a better understanding of how cells use biochemical pathways can lead to new approaches to treat diseases such as cancer and diabetes.

In their study, the team shows that as fat cells develop, they vary the types of nutrients they process to grow and make fat and energy.

They studied the metabolism of fat cells from the stage before they are fully differentiated into fat cells through to when they are fully mature fat cells.

The researchers found that in the early stages of development – when the fat cells or adipocytes are still in an immature, pre-adipocyte state – they prefer to consume glucose to fuel their growth and make energy.

But as the fat cells mature, they begin to metabolize not only glucose – a simple sugar – but also a more complex set of molecules called branched-chain amino acids. These are a small subset of the amino acids essential for human growth and health.

The researchers also found that the mature fat cells appear to produce fatty acids, in part, from essential amino acids rather than sugar only.

The discovery is important because people with obesity and diabetes typically have higher levels of branched-chain amino acids in their bloodstream and suggests this could be a result of disruption in their fat cells.

First author Courtney Green, who is working toward a PhD in bioengineering, says the study takes a step toward understanding why people with diabetes and obesity show higher levels of these amino acids, and adds:

“The next step is to understand how and why this metabolic pathway becomes impaired in the fat cells of these individuals.”

The team used cultured cells to make their observations. They grew the cells in nutrients enriched with carbon-13 isotopes – a lab technique for tracing molecules as they progress through various processes at the cell level in animal and human studies.

Using this tracing method, they were able to work out which nutrients the cells metabolized and what they produced at each stage of differentiation – from immature pre-adipocytes to fully mature fat cells.

Prof. Metallo concludes:

This study highlights how specific tissues in our bodies use particular nutrients. By understanding fat cell metabolism at the molecular level, we are laying the groundwork for further research to identify better drug targets for treating diabetes and obesity.”

Last month, Medical News Today learned about another biological study that uncovered new insights into the body’s varied response to exercise. One of the new revelations is that endurance exercise encourages new blood vessels to grow and thus increase stamina, while resistance exercise not only boosts blood vessel growth, it also stimulates muscle growth.