Plasma fatty acid levels and gene expression related to lipid metabolism in peripheral blood mononuclear cells

Solid evidence indicates that intake of marine n-3 fatty acids lower serum triglycerides, and that replacing saturated fatty acids (SFA) with polyunsaturated fatty acids (PUFA) reduces plasma total cholesterol and LDL-cholesterol. The molecular mechanisms underlying these health beneficial effects are however not completely elucidated. The aim of this study was to investigate the expression of genes related to lipid metabolism in peripheral blood mononuclear cells (PBMC) depending on the plasma levels of n-6 and n-3 fatty acids and the SFA to PUFA ratio. This study is a cross-sectional sub-study of a randomised controlled trial designed to investigate the health effects of fish oil intake (Ottestad el al, 2012, Myhrstad et al, 2014). The study population was grouped into tertiles three times according to the plasma fatty acid levels of n-6 and n-3 fatty acids and the plasma SFA to PUFA ratio at the end of study by arranging samples from the highest to the lowest value. Peripheral blood monnucelar cell gene expression between subjects in the highest (n=18) and the lowest (n=18) tertile within each arrangement in groups were further compared. A total of 285 genes encoding proteins related to cholesterol and triglyceride metabolism were selected for this explorative analysis. 161 genes were defined as expressed on the HumanHT-12 v4 microarray and included in the statistical analyses.