Identification of Mest/Peg1 gene expression as a predictive biomarker of adipose tissue expansion sensitive to dietary anti-obesity interventions.

Food components with anti-obesity properties are commonly evaluated using mouse models of diet-induced obesity. The ability of these components to reduce or prevent white adipose tissue (WAT) accumulation is usually tested in feeding trials of several weeks duration in order to detect significant effects on fat mass expansion. Here, we aimed to identify early, predictive biomarkers for WAT expansion. We performed a 5-day high-fat diet (HFD) feeding trial with C57BL/6J mice using different established anti-obesity interventions: epigallocatechin gallate, replacing dietary lipids by n-3 PUFA, and increasing dietary protein. WAT gene expression was analyzed of genes known to be similarly affected by short- and long-term HFD. Gene expression of Leptin and Mest (mesoderm-specific transcript) was increased by HFD and normalized by all anti-obesity interventions. In a second experiment, translatability to whole blood-based expression data was assessed. Mice were challenged for 21 days with a HFD without or with simultaneous treatment with anti-obesity bioactives, hydroxytyrosol or resveratrol, and compared for parameters including Leptin and Mest expression in whole blood at day 5. While Leptin mRNA could not be detected in mouse whole blood, there was an induction of Mest mRNA by HFD which was suppressed by hydroxytyrosol. Moreover, Mest expression in whole blood at day 5 positively correlated with adiposity and negatively with lean body mass and the subcutaneous/visceral fat ratio at day 21. We conclude that gene expression of Leptin and Mest in WAT and of Mest in whole blood represent early, predictive markers of adipose tissue expansion of potential usefulness in nutritional studies and trials.