Brown adipose tissue (BAT) can generate heat by burning fatty acids, a process mediated by uncoupling protein 1 (UCP1). White adipose tissue (WAT) depots can gain BAT-like properties, and various studies have suggested that females have more active BAT or BAT-like WAT. We studied sex differences in BAT-like properties of human perirenal adipose tissue.
Perirenal and subcutaneous adipose tissue was obtained from 20 male and 24 female healthy live kidney donors. Mesenchymal stem cells (MSCs), adipocyte precursor cells, were isolated from these depots to study whether intrinsic factors control BAT-like properties of the adipose tissue depots.
When average outside temperature a week before harvesting was below 11°C, brown-like adipocytes expressing UCP1 were present in perirenal adipose tissue of women, but not of men. MSCs derived from perirenal adipose tissue expressed significantly more UCP1 when from female origin compared to male origin (P = 0.009). However, UCP1 protein content and oxygen consumption rate did not differ between adipocytes derived from male and female perirenal MSCs.
Female perirenal adipose tissue has a higher potency to gain BAT-like properties than male perirenal adipose tissue. The degree of gaining BAT-like properties depends on sex-specific intrinsic factors and environmental triggers such as temperature.