Brown fat is linked to lower heart disease risk
A Nature study of more than 100 000 cancer patients is observational, and losartan's effect on this tissue was seen only in mice and cells.
A team at Rockefeller University, using data from Memorial Sloan Kettering Cancer Center, published a study in Nature on Oct. 14 about brown fat, a tissue that burns energy to produce heat. The U.S. National Institutes of Health (NIH) shared the work.
Using an artificial intelligence tool, the team analyzed PET/CT scans of more than 100 000 people under cancer surveillance (101,243 adults, according to the NIH) and matched them against more than 500 diagnosis codes. People with detectable brown fat had less cardiovascular disease, anxiety and depression, and better glucose, lipid and inflammation readings. The authors stress that these are associations and do not show that the tissue causes those outcomes.
What was seen with losartan
Patients taking angiotensin receptor blockers, a class of blood pressure drugs that includes losartan, showed more brown fat on their scans. In cultured cells of this tissue and in healthy mice, losartan raised metabolic activity and energy expenditure without changing weight. The authors attribute the effect to a mechanism different from the one that lowers blood pressure. The study does not report how many mice were in each group, and the drug has not been tested in people for this purpose.
Paul Cohen, the senior author, told the university: "This is just a start." First author Nicolás Gómez-Banoy said the goal would be to stimulate brown fat in people with normal blood pressure, something that has not yet been done.
The work expands on a 2021 study of about 50 000 patients at the same center. All the clinical data come from a single cancer hospital, and the study mentions possible downsides of the tissue, such as more osteoporosis and skin disease, that remain to be studied.
The results describe cancer patients at a New York center and, for the drug part, mice and cells; they are not a recommendation for the general population. Nothing indicates that anyone should start, change or stop a medication, a decision that belongs to each patient and their doctor. The study's funding does not appear in the sources consulted.
