Potential Good Fat Biomarker

Brown fat cells can burn fat to generate heat. University of Bonn researchers have discovered a new method to measure the activity of brown fat cells in humans and mice. The researchers showed that microRNA-92a can be used as an indirect measure for the activity of energy consuming brown fat cells. They showed that a small blood sample was sufficient.

People who want to lose weight often encounter boundaries: No matter what diet they try, the pounds won’t drop. Being overweight and obese can have severe health consequences, and has shown to increase a person’s chance of developing type-2-diabetes or cardiovascular diseases.

These scientists, led by Prof. Dr. Alexander Pfeifer, have reported that they found a potential serum biomarker for brown adipose tissue (BAT) activity. They summarized their work April 27 in the journal Nature Communications, in an article entitled, “Exosomal MicroRNA miR-92a Concentration in Serum Reflects Human Brown Fat Activity.”

“Here we show that brown adipocytes release exosomes and that BAT activation increases exosome release,” wrote the article’s authors. “Profiling miRNAs in exosomes released from brown adipocytes, and in exosomes isolated from mouse serum, we show that levels of miRNAs change after BAT activation in vitro and in vivo.”

Dr. Pfeifer noted that microRNAs (miRNAs) are known to be responsible for the regulation of genes. He also indicated that his team showed for the first time that brown fat cells deliver these miRNAs into the blood by packaging into so-called exosomes, which “can be seen as little packages that are delivered by the brown fat cells through the circulation.” However, Prof. Pfeiffer added, “to whom the packages are delivered is yet unknown.”

Many miRNAs were investigated during the investigation. It turned out that miR-92a, which is present in human and mice, is related to brown fat activity. “[Serum] concentrations of exosomal miR-92a inversely correlate with human BAT activity measured by ¹⁸F-FDG PET/CT in two unique and independent cohorts comprising 41 healthy individuals,” explained the study’s authors. “Thus, exosomal miR-92a represents a potential serum biomarker for BAT activity in mice and humans.”

“miR-92a seems to be a promising biomarker to test new drugs in the field of weight reduction or transition from white-to-brown fat in humans,” asserted Prof. Pfeifer. “This promising biomarker should be tested in larger cohorts.” This new method might enable advances in obesity research and related fields.