Adiposity dependent apelin gene expression: relationships with oxidative and inflammation markers

It has been reported that apelin functions as an adipokine, which has been associated to obesity and insulin resistance. The objective of this study was to analyze the apelin mRNA expression in white adipose tissue (WAT) from high-fat (Cafeteria) fed rats, in order to examine potential relationships with obesity markers and other related risk factors. Animals fed on the high-fat diet during 56 days increased their body weight, total body fat and WAT depots weights when compared to controls. Apelin subcutaneous mRNA expression was higher in the Cafeteria than in the Control fed group and this increase was partially reversed by dietary vitamin C supplementation. Statistically significant associations between subcutaneous apelin gene expression and almost all the studied variables were identified, being of special interest the correlations found with serum leptin (r=0.517), liver malondialdehyde (MDA) levels (r=0.477), and leptin, IRS-3 and IL-1ra retroperitoneal mRNA expression (r=0.701; r=0.692 and r=0.561, respectively). These associations evidence a possible role for apelin in the excessive weight gain induced by high-fat feeding and increased adiposity, insulin-resistance, liver oxidative stress and inflammation.