Dataset Information

Regulation of lipid metabolism-related gene expression in whole blood cells of normo- and dyslipidemic men after fish oil supplementation.

ABSTRACT:

Background

Beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on the lipid levels of dyslipidemic subjects are widely described in the literature. However, the underlying molecular mechanisms are largely unknown. The aim of this study was to investigate the effects of n-3 PUFAs on the expression of lipid metabolism-related genes in normo- and dyslipidemic men to unveil potential genes and pathways affecting lipid metabolism.

Methods

Ten normo- and ten dyslipidemic men were supplemented for twelve weeks with six fish oil capsules per day, providing 1.14 g docosahexaenoic acid and 1.56 g eicosapentaenoic acid. The gene expression levels were determined by whole genome microarray analysis and quantitative real-time polymerase chain reaction.

Results

Several transcription factors (peroxisome proliferator-activated receptor α (PPARα), retinoid X receptor (RXR) α, RXRγ, hepatic nuclear factor (HNF) 6, and HNF1ß) as well as other genes related to triacylglycerol (TG) synthesis or high-density lipoprotein (HDL-C) and cholesterol metabolism (phospholipids transfer protein, ATP-binding cassette sub-family G member 5, 2-acylglycerol O-acyltransferase (MOGAT) 3, MOGAT2, diacylglycerol O-acyltransferase 1, sterol O-acyltransferase 1, apolipoprotein CII, and low-density lipoprotein receptor) were regulated after n-3 PUFA supplementation, especially in dyslipidemic men.

Conclusion

Gene expression analyses revealed several possible molecular pathways by which n-3 PUFAs lower the TG level and increase the HDL-C and low-density lipoprotein level, whereupon the regulation of PPARα appear to play a central role.

Trial registration

ClinicalTrials.gov (ID: NCT01089231).

SUBMITTER: Schmidt S

PROVIDER: S-EPMC3543286 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

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Publications

Regulation of lipid metabolism-related gene expression in whole blood cells of normo- and dyslipidemic men after fish oil supplementation.

Schmidt Simone S Willers Janina J Stahl Frank F Mutz Kai-Oliver KO Scheper Thomas T Hahn Andreas A Schuchardt Jan Philipp JP

Lipids in health and disease 20121214

<h4>Background</h4>Beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on the lipid levels of dyslipidemic subjects are widely described in the literature. However, the underlying molecular mechanisms are largely unknown. The aim of this study was to investigate the effects of n-3 PUFAs on the expression of lipid metabolism-related genes in normo- and dyslipidemic men to unveil potential genes and pathways affecting lipid metabolism.<h4>Methods</h4>Ten normo- and ten dyslipidem ...[more]

PMID: 23241455

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Project description:Beneficial effects of long-chain omega-3 polyunsaturated fatty acids (n-3 FAs) are generally well-known from epidemiological studies, but the various mechanisms of action are not completely clarified. Regulation of gene expression is one known mechanism of action, but only very limited data of regulated pathways in humans after n-3 FA supplementation are available. Up to now, no studies compared gene expression changes after n-3 FA supplementation between normolipidemic and dyslipidemic subjects. Therefore, the aim of this study was to investigate the effects of n-3 FA administration on whole genome expression profiles in the blood of normo- and dyslipidemic subjects. We conducted an intervention study with normo- and dyslipidemic men aged between 29 and 51 years, which were subdivided into four groups with a balanced age distribution and randomized to either six fish oil capsules per day providing 1.5 g docosahexaenoic acid and 1.0 g eicosapentaenoic acid or corn oil capsules rich in linoleic acid per day for a period of 12 weeks. Venous blood samples were collected at baseline as well as after 4 hours, 1 week and 12 weeks of supplementation. For each investigation time point, the samples of each group were pooled together to minimize inter-individual variability. All subjects have successfully completed the study, but for the microarray experiments, nine subject samples were excluded. Therefore, the microarray experiments are based on the following group characteristics: normolipidemic fish oil group (FO-N): pool of nine RNAs from normolipidemic subjects supplemented with fish oil; normolipidemic corn oil group (CO-N): pool of six RNAs from normolipidemic subjects supplemented with corn oil; dyslipidemic corn oil group (CO-D): pool of eight RNAs from dyslipidemic subjects supplemented with corn oil; dyslipidemic fish oil group (FO-D): pool of nine RNAs from dyslipidemic subjects supplemented with fish oil. The twenty normolipidemic and the twenty dyslipidemic subjects were subdivided into two groups. Thus, a total of four groups with ten men per group passed through the study. To realize a comparable mean age between groups, the formation of groups was performed by stratified allocation according to subject's age. The four study groups were randomly assigned to different study products by an uninvolved collaborator. Subjects ingested either six FO or six corn oil (CO) capsules per day for a period of twelve weeks. The daily n-3 PUFA intake via FO capsules was 2.7 g (1.14 g DHA and 1.56 g EPA). The predominant FA of the CO capsules was the omega-6 (n-6) PUFA linoleic acid (LA, 18:2n-6). Thus, the daily LA intake via CO capsules was 3.05 g LA. The subjects were instructed to ingest the capsules together with food, three in the morning and three in the evening, and to maintain their usual exercise and dietary habits throughout the intervention time. As an exception, at the first intervention day, all six capsules were ingested at the same time in the morning after a standardised breakfast. During each visit, fasting blood samples were collected by venepuncture. Additionally, participants completed a questionnaire to obtain information about changes in medication, dietary (e.g., changes in weekly fish intake, preferred fish dishes or species, respectively) and lifestyle habits (e.g., physical activity), as well as the tolerability of the capsules. This record summarizes the results of 16 microarrays. The samples originate from whole blood of normo- and dyslipidemic subjects supplemented with either fish oil or corn oil for 4 h, 1 week and 12 weeks. Microarrays were hybridized in a loop design with one common reference using a dye-swap approach.

Project description:BackgroundThe beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs), especially in dyslipidemic subjects with a high risk of cardiovascular disease, are widely described in the literature. A lot of effects of n-3 PUFAs and their oxidized metabolites are triggered by regulating the expression of genes. Currently, it is uncertain if the administration of n-3 PUFAs results in different expression changes of genes related to antioxidative mechanisms in normo- and dyslipidemic subjects, which may partly explain their cardioprotective effects. The aim of this study was to investigate the effects of n-3 PUFA supplementation on expression changes of genes involved in oxidative processes.MethodsTen normo- and ten dyslipidemic men were supplemented for twelve weeks with fish oil capsules, providing 1.14 g docosahexaenoic acid and 1.56 g eicosapentaenoic acid. Gene expression levels were determined by whole genome microarray analysis and quantitative real-time polymerase chain reaction (qRT-PCR).ResultsUsing microarrays, we discovered an increased expression of antioxidative enzymes and a decreased expression of pro-oxidative and tissue enzymes, such as cytochrome P450 enzymes and matrix metalloproteinases, in both normo- and dyslipidemic men. An up-regulation of catalase and heme oxigenase 2 in both normo- and dyslipidemic subjects and an up-regulation of cytochrome P450 enzyme 1A2 only in dyslipidemic subjects could be observed by qRT-PCR analysis.ConclusionsSupplementation of normo- and dyslipidemic subjects with n-3 PUFAs changed the expression of genes related to oxidative processes, which may suggest antioxidative and potential cardioprotective effects of n-3 PUFAs. Further studies combining genetic and metabolic endpoints are needed to verify the regulative effects of n-3 PUFAs in antioxidative gene expression to better understand their beneficial effects in health and disease prevention.Trial registrationClinicalTrials.gov (ID: NCT01089231).

Project description:Colorectal cancer is the second leading cause of cancer-related death within the United States. Animal models and observational studies have suggested that marine-derived n-3 polyunsaturated fatty acids [PUFA] such as eicosapentanoic acid [EPA] and docosahexanoic acid [DHA] may reduce the risk of colorectal cancer. In addition, it may be the relative proportion of n-3 to n-6 PUFAs that best determines the chemopreventive effects of fish oils. This ratio is important because the n-6 PUFA, arachidonic acid (ARA), is converted via the cyclo-oxygenase (COX) pathway to prostaglandin E2 (PGE2), an inflammatory eicosanoid overproduced in colorectal neoplasms while EPA is converted to the anti-inflammatory prostaglandin E3 (PGE3). While the ratio of n-6 to n-3 PUFAs can be altered through dietary changes, genetic factors may also influence this ratio. Recent genetic studies have demonstrated that much of the tissue levels of ARA is determined by differences in a gene called fatty acid desaturase 1 (FADS1). FADS1 is the rate-limiting enzyme in the conversion of linoleic acid, the most commonly consumed PUFA in the Western diet, to ARA, and one particular genetic variant caller rs174537 is associated with lower fatty acid desaturase activity and subsequently lower tissue levels of ARA. The study hypothesis is that individuals with genetically determined lower activity of FADS1 will derive greater benefit from fish oil supplementation than individuals with higher FADS1 activity because of lower tissue levels of ARA and subsequently a more favorable n-6 to n-3 PUFA ratio. To test this hypothesis the investigators will recruit 150 participants with recently identified adenomatous polyps and conduct a 6-month double blind 3 X 2 factorial randomized controlled trial. The first factor will be FADS1 genotype (GG, GT, and TT) and the second factor will be fish oil supplementation (fish oil versus placebo). The primary outcome will be the change in rectal epithelial cell growth and cell death. Secondary outcomes will include rectal epithelial cell expression of genes important in PGE2 production, rectal cell production of PGE2 and PGE3, rectal mucosal tissue levels of fatty acids, and changes in biomarkers of inflammation (C-reactive protein), adipokines (leptin, adiponectin), and markers of insulin sensitivity. The specific aims include: 1) to determine the efficacy of fish oil supplements on rectal epithelial cell proliferation indexes and markers of rectal crypt apoptosis, and 2) to determine the effect of genetically-determined fatty acid desaturase 1 activity on fish oil supplementation for colorectal cancer chemoprevention. The investigators long-term objectives are to determine genetic factors that might influence the efficacy of fish oil supplementation in order to conduct a more definitive adenoma recurrence trial using marine-derived n-3 PUFAs. The investigators anticipate that fish oil will have anti-neoplastic effect and individuals with low FADS1 activity will have a greater response compared to individuals with high FADS1 activity

Project description:Fish oil supplementation is generally seen as beneficial for human health, due to the presence of n-3 polyunsaturated fatty acids (n-3 PUFAs). These fatty acids can elicit their effect through changes in gene expression. Effects of n-3 PUFAs on gene expression of inflammatory and atherogenic markers have been shown in several in vitro and animal studies. However, little evidence is available on human in vivo studies on n-3 PUFA related gene expression. In the present study we investigate the effects of EPA and DHA supplementation for 6 months on gene expression profiles of peripheral blood mononuclear cells (PBMCs). Whole genome microarray analysis was performed on PBMC RNA from subjects who received 1.8 grams of EPA and DHA in capsules (n=23) or capsules containing high oleic acid sunflower oil (HOSF)(n=25). Intake of EPA and DHA resulted in a change of 1040 genes. We found a down-regulation in inflammatory and atherogenic related pathways, such as NF-ÎºB signaling, eicosanoid synthesis, scavenger receptors activity and cell adhesion. These results seem to point to an improvement in health status, in which lymphocytes are less prone to produce chemokines and adhesion molecules and monocytes show reduced susceptibility to differentiate into foam cells. Overall, beneficial effects of n-3 PUFAs that have been described in vitro and in animal studies, were shown in vivo in human subjects in this study. This not only confirms that EPA and DHA elicits beneficial effects on inflammatory and atherogenic processes of elderly subjects, but also shows that PBMC gene expression profiles can be used to show effects of nutrition on human health status. Fasting venous blood samples were collected at baseline and after 26 weeks of supplementation with either 1.8 g EPA and DHA or HOSF. 4 ml blood was collected for PBMC isolation, using BD Vacutainer Cell Preparation Tubes with sodium citrate (BD, Breda, The Netherlands). Immediately after blood collection PBMCs were isolated according to the manufacturerâs manual. PBMC RNA was isolated from all PBMC samples using Qiagen RNeasy Micro kit (Qiagen, Venlo, the Netherlands). Total RNA from PBMCs from 48 subjects was labeled using a one-cycle cDNA labeling kit (MessageAmpTM II-Biotin Enhanced Kit, Ambion, Inc.) and hybridized to custom designed NuGO GeneChip arrays.

Dataset Information

Regulation of lipid metabolism-related gene expression in whole blood cells of normo- and dyslipidemic men after fish oil supplementation.

Background

Methods

Results

Conclusion

Trial registration

Publications

Regulation of lipid metabolism-related gene expression in whole blood cells of normo- and dyslipidemic men after fish oil supplementation.

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