Depot-specific differences in fatty acid composition and distinct associations with lipogenic gene expression in abdominal adipose tissue of obese women
Cardiometabolic diseases are primarily linked to enlarged visceral adipose tissue (VAT). However, some data suggest heterogeneity within the subcutaneous adipose tissue (SAT) depot with potential metabolic differences between the superficial SAT (sSAT) and deep SAT (dSAT) compartments. We aimed to investigate the heterogeneity of these three depots with regard to fatty acid (FA) composition and gene expression. Adipose tissue biopsies were collected from 75 obese women undergoing laparoscopic gastric bypass surgery. FA composition and gene expression were determined with gas chromatography and quantitative real-time-PCR, respectively. Stearoyl CoA desaturase-1 (SCD-1) activity was estimated by product-to-precursor FA ratios. All polyunsaturated FAs (PUFA) with 20 carbons were consistently lower in VAT than either SAT depots, whereas essential PUFA (linoleic acid, 18:2n-6 and α-linolenic acid, 18:3n-3) were similar between all three depots. Lauric and palmitic acid were higher and lower in VAT, respectively. The SCD-1 product palmitoleic acid as well as estimated SCD-1 activity was higher in VAT than SAT. Overall, there was a distinct association pattern between lipid metabolizing genes and individual FAs in VAT. In conclusion, SAT and VAT are two distinct depots with regard to FA composition and expression of key lipogenic genes. However, the small differences between sSAT and dSAT suggest that FA metabolism of SAT is rather homogenous.