The intake of a high-fat diet and grape seed procyanidins induces gene expression changes in peripheral blood mononuclear cells of hamsters: capturing alterations in lipid and cholesterol metabolisms.

We previously demonstrated that hamsters that were fed either a standard diet (STD) or a high-fat diet (HFD) and treated with a grape seed procyanidin extract (GSPE) showed decreased adiposity and circulating levels of free fatty acids compared with hamsters treated with a vehicle (Caimari et al. in Int J Obes 37:576-83, 2013, doi: 10.1038/ijo.2012.75 ). Here, we tested whether the gene expression changes in peripheral blood mononuclear cells (PBMCs) can reflect these metabolic effects and the dyslipidaemia produced by the HFD feeding in the same cohort of animals. The mRNA levels of a subset of genes were also studied in the liver in order to evaluate the capacity of PBMCs to reflect the metabolic adaptations that occur in this organ. In PBMCs, we reported a simultaneous up-regulation of the lipid-related genes involved in both the anabolic (pparγ, acc1 and gpat) and the catabolic (pparα, ucp2, atgl and hsl) pathways in response to the GSPE treatment, similar but no identical to previous observations in retroperitoneal white adipose tissues of these animals. Furthermore, the key cholesterol metabolism genes srebp2 and ldlr were significantly down-regulated in PBMCs of both HFD-fed groups compared with the STD groups. Although the expression of srebp2 in the liver followed a similar pattern to that obtained in PBMCs, no comparable changes were found between the liver and PBMCs in the expression of most of the studied genes. In conclusion, our results highlight the potential of PBMCs as a high accessible tissue for the indirect study of cholesterol and adipose tissue metabolism dynamics.