Gene expression profile of PBMCs after intake of fish oil for seven weeks compared to high oleic sunflower oil

Fish oil supplementation has been shown to alter gene expression of mononuclear cells both in vitro and in vivo. However, little is known about the total transcriptomic profile in healthy subjects after intake of fish oil compared to a control group. The objective was to examine the gene expression profile in peripheral blood mononuclear cells (PBMCs) in healthy subjects after intake of fish oil for seven weeks using whole-genome transcriptomic analysis. In a double-blinded randomized controlled study, healthy subjects received capsules containing either 8 g/d of fish oil (1.6 g/d EPA+DHA) (n=17) or 8 g/d of high oleic sunflower oil (n=19) for seven weeks. The results provide important information on how fish oil may modulate basic cellular processes involved in normal cell function and lymphocyte activation such as ER stress, cell cycle and apoptosis. The subjects were taking 16 capsules/d containing 8 g/d of either fish oil (FO) or high oleic sunflower oil (HOSO) for seven weeks. Subjects in the FO group received capsules containing 0.7 g/d EPA + 0.9 g/d DHA from cod liver oil (Gadidae sp., TINE EPADHA Oil 1200) provided by TINE SA (Oslo, Norway) and subjects in HOSO group received high oleic sunflower oil purchased from AarhusKarlshamn AB (Malmӧ, Sweden). Prior to the baseline visit (visit 2, wk 0), the subjects conducted a four-week washout period, where foods containing marine n-3 fatty acids were excluded from the diet. The first three weeks of the intervention period the subjects conducted a fully-controlled isocaloric diet, provided with all food and beverages at Akershus University College, Norway. During the last four weeks of the intervention the subjects returned to their habitual diet. Use of fish, fish products, marine n-3 enriched food or dietary supplements was not allowed during the entire study period of 11 weeks. The study was registered at www.clinicaltrial.gov (IDno. NCT01034423). The subjects met for four visits and blood samples for the transcriptome analyses were collected at wk 0, 3 and 7. After blood collection, PBMCs were isolated by using the BD Vacutainer Cell Preparation tubes according to the manufacturer's instructions (Becton, Dickinson and Company, NJ 07417, USA). Pellets were frozen and stored at -80o C for further RNA isolation.