Decreased Adipose Lipid Turnover Associates With Cardiometabolic Risk and the Metabolic Syndrome

BACKGROUND: Disturbed white adipose tissue function is important for cardiometabolic risk and metabolic syndrome (MetS). Whether this involves adipose lipid turnover (lipolysis and synthesis of triglycerides) is unknown and was presently investigated in subcutaneous adipose tissue, the body’s largest fat depot. METHODS: In cross-sectional studies in 78 subjects, adipose lipid age, representing overall lipid turnover (mobilization and storage), and lipid storage capacity were assessed by the incorporation of atmospheric 14 C into adipose lipids. Adipose lipid age from an algorithm of adipocyte lipolysis and clinical parameters was also determined in 185 subjects. Adult Treatment Panel III (ATPIII) scoring defined MetS (scores 3–5) or healthy (score 0). ANOVA or ANCOVA and t test were used for statistical comparison. Because there was no method interaction to determine lipid age, the 2 groups were combined. RESULTS: Lipid age increased by incremental ATPIII score (F=42; P <0.0001) and was 2-fold advanced in MetS (t=11.3; P <0.0001). The correlation with lipid age was independent of age, sex, body mass index, waist-to-hip ratio, sedentary lifestyle, absence of obesity, and adipose insulin resistance (F=10.7; P <0.0001). Lipid storage capacity was not related to the ATPIII score (F=1.0; P =0.44) or MetS (t=−0.9; P =0.35). Adipocyte lipolysis activation was decreased in MetS and inversely related to incremental ATPIII score, suggesting that decreased lipid mobilization is the major factor behind high lipid age in these conditions. CONCLUSIONS: Despite normal lipid assimilation capacity, abdominal subcutaneous adipose lipid turnover is decreased in MetS and high ATPIII score because of impaired ability to mobilize lipids involving low adipocyte lipolysis activation.