Aging selectively dampens oscillation of lipid abundance in white and brown adipose tissue

Lipid metabolism is under the control of the circadian system and circadian dysregulation has been linked to obesity and dyslipidemia. These factors and outcomes have also been associated to, or affected by, the process of aging. Here, we investigated whether murine white (WAT) and brown (BAT) adipose tissue lipids exhibit rhythmicity and if this is affected by aging. To this end, we have measured the 24 h lipid profiles of WAT and BAT using a global lipidomics analysis of >1100 lipids. We observed rhythmicity in nearly all lipid classes including glycerolipids, glycerophospholipids, sterol lipids and sphingolipids. Overall, similar to 22% of the analyzed lipids were considered rhythmic in WAT and BAT. Despite a general accumulation of lipids upon aging the fraction of oscillating lipids decreased in both tissues to 14% and 18%, respectively. Diurnal profiles of lipids in BAT appeared to depend on the lipid acyl chain length and this specific regulation was lost in aged mice. Our study revealed how aging affects the rhythmicity of lipid metabolism and could contribute to the quest for targets that improve diurnal lipid homeostasis to maintain cardiometabolic health during aging.

Automated summary

The study reveals that lipid metabolism is controlled by the circadian system, and aging affects the rhythmicity of lipid metabolism, leading to a decrease in oscillating lipids with age. While lipid accumulation increases with aging, the percentage of rhythmic lipids decreases, and the diurnal profiles of lipids in brown adipose tissue may be dependent on the length of the lipid acyl chain, a regulation that is lost in aged mice.