Gene expression profile following an oral unsaturated fat load in abdominal obese subjects

Our aim was to evaluate the postprandial effect of an oral fat load test (OFLT) rich in unsaturated fatty acids on gene expression profile in peripheral blood mononuclear cells (PBMC) from subjects with abdominal obesity as an insulin resistance model and controls.

A total of 20 controls and 20 abdominal obese patients were studied. Metabolic parameters and oxidative stress markers were measured with standardized protocols. The whole gene expression at fasting state and after the OFLT (0, 4 and 8 h) was analysed using human HT-12-v4 expression beadchips, from Illumina.

We found a significant decrease in plasma glucose, insulin and oxidative stress markers in abdominal obese patients and controls. We found beneficial metabolic postprandial gene expression in three genes: FKBP5, DDIT4 and DHRS9. Following an OFLT, the postprandial mRNA expression of FKBP5, and DDIT4 was downregulated while that of DHRS9 was overexpressed, both in nondiabetic normolipidemic subjects and in insulin-resistant subjects with abdominal obesity.

Our results suggest that an OFLT rich in unsaturated fatty acids downregulates the expression of FKBP5, coding for the glucocorticoid receptor pathway, and that of DDIT4, involved in the oxidative stress response. These changes could favourably influence the insulin resistance and oxidative stress status in the postprandial state.