Brown fat is the “good” fat that burns, rather than stores, calories. It was previously thought that this special type of fat could only be found in infants, but upon its identification in adults, it became a major target for treating health conditions such as obesity and diabetes. The functionality of brown fat, or brown adipose tissue (BAT), includes generating heat in response to cold temperatures as well as increasing insulin sensitivity. Browning, the process by which white fat is converted into brown-like fat, might then be beneficial to those with weight-related diseases. Many efforts have gone into understanding this process and discovering drugs that may assist with browning. A recent study built on such efforts by identifying a naturally occurring molecule that may induce this process.
Image Source: Science Photo Library – STEVE GSCHMEISSNER.
Researchers have found that a lipid known as 12,13-diHOME induces brown fat activity. They theorized that this lipokine, or lipid hormone, circulates in the bloodstream and causes BAT to take up other surrounding fats and break them down. Researchers identified the lipid by taking blood samples from nine human volunteers, once at room temperature and once at a colder temperature. Under the cold temperature exposure, the volunteers would have increased activation of brown fat. After analyzing the lipid concentrations in the samples, they noticed that significantly more 12,13-diHOME was found in samples taken in the cold, suggesting that 12,13-diHOME is activated in response to cold exposure. The researchers then went on to test its therapeutic potential by introducing the lipid into mice. They found that mice treated with the lipid were able to tolerate cold exposure better, reaffirming the hypothesis that the lipid activated brown fat activity, generating heat and ultimately keeping the mice warm. Although the study was not conclusive on the lipid’s role in humans, the researchers believed that the lipid could be used as a biomarker for brown fat activation.
Overall, the results of this study suggest that 12,13-diHOME may be used to activate brown fat. Because the lipid is naturally produced by our bodies, its usage as a therapeutic for metabolic disorders would help to avoid the risks generally associated with drugs, such as off-target toxicity, and provide a safer alternative treatment.
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