Oleic acid regulates the circadian rhythm of adipose tissue in obesity

The effect of oleic acid (OA) on the regulation of the circadian rhythm present in human visceral (VAT) and subcutaneous (SAT) adipose tissue from patients with morbid obesity has not been analyzed yet. VAT and SAT explants from patients with morbid obesity were incubated with OA to analyze the circadian regulation of clock and other genes related to lipid metabolism (SREBP-1c, FAS, LPL and CPT1), and their association with baseline variables and the improvement of these patients after bariatric surgery. There were significant differences in amplitude and acrophase in VAT with respect to SAT. In VAT, body weight negatively correlated with BMAL1 and CRY1 amplitude, and REVERB alpha acrophase; body mass index (BMI) negatively correlated with REVERB alpha acrophase; and waist circumference negatively correlated with PER3 acrophase. In SAT, BMI negatively corre-lated with CLOCK amplitude, and CLOCK, REVERB alpha and CRY2 MESOR; and waist circumference negatively correlated with PER3 amplitude and acrophase. A greater short-term improvement of body weight, BMI and waist circumference in patients with morbid obesity after bariatric surgery was associated with a lower CRY1 and CRY2 amplitude and an earlier PER1 and PER3 acrophase in SAT. OA produced a more relevant circadian rhythm and increased the amplitude of most clock genes and lipid metabolism-related genes. OA regulated the acrophase of most clock genes in VAT and SAT, placing CLOCK/BMAL1 in antiphase with regard to the other genes. OA increased the circadian rhythmicity, although with slight differences between adipose tissues. These differences could determine its different behavior in obesity.

Automated summary

The effect of oleic acid on the regulation of circadian rhythm in visceral and subcutaneous adipose tissue of morbidly obese patients has not been studied yet. This study found that body weight, BMI, and waist circumference were correlated with different clock genes in both VAT and SAT. After bariatric surgery, the improvement in body weight, BMI, and waist circumference was associated with specific clock genes in SAT.