Omega-3 polyunsaturated fatty acids attenuate inflammatory activation and alter differentiation in human adipocytes.

BACKGROUND: Omega-3 polyunsaturated fatty acids, specifically the fish-oil-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been proposed as inflammation-resolving agents via their effects on adipose tissue. OBJECTIVE: We proposed to determine the effects of EPA and DHA on human adipocyte differentiation and inflammatory activation in vitro. METHODS: Primary human subcutaneous adipocytes from lean and obese subjects were treated with 100 µM EPA and/or DHA throughout differentiation (differentiation studies) or for 72 h postdifferentiation (inflammatory studies). THP-1 monocytes were added to adipocyte wells for co-culture experiments. Subcutaneous and visceral adipose explants from obese subjects were treated for 72 h with EPA and DHA. Oil Red O staining was performed on live cells. Cells were collected for mRNA analysis by quantitative polymerase chain reaction, and media were collected for protein quantification by enzyme-linked immunosorbent assay. RESULTS: Incubation with EPA and/or DHA attenuated inflammatory response to lipopolysaccharide (LPS) and monocyte co-culture with reduction in post-LPS mRNA expression and protein levels of IL6, CCL2 and CX3CL1. Expression of inflammatory genes was also reduced in the endogenous inflammatory response in obese adipose. Both DHA and EPA reduced lipid droplet formation and lipogenic gene expression without alteration in expression of adipogenic genes or adiponectin secretion. CONCLUSIONS: EPA and DHA attenuate inflammatory activation of in vitro human adipocytes and reduce lipogenesis.

Expression of Calgranulin Genes S100A8, S100A9 and S100A12 Is Modulated by n-3 PUFA during Inflammation in Adipose Tissue and Mononuclear Cells.

Calgranulin genes (S100A8, S100A9 and S100A12) play key immune response roles in inflammatory disorders, including cardiovascular disease. Long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) may have systemic and adipose tissue-specific anti-inflammatory and cardio-protective action. Interactions between calgranulins and the unsaturated fatty acid arachidonic acid (AA) have been reported, yet little is known about the relationship between calgranulins and the LC n-3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We explored tissue-specific action of calgranulins in the setting of evoked endotoxemia and n-3 PUFA supplementation. Expression of calgranulins in adipose tissue in vivo was assessed by RNA sequencing (RNASeq) before and after n-3 PUFA supplementation and evoked endotoxemia in the fenofibrate and omega-3 fatty acid modulation of endotoxemia (FFAME) Study. Subjects received n-3 PUFA (n = 8; 3600mg/day EPA/DHA) or matched placebo (n = 6) for 6-8 weeks, before completing an endotoxin challenge (LPS 0.6 ng/kg). Calgranulin genes were up-regulated post-LPS, with greater increase in n-3 PUFA (S100A8 15-fold, p = 0.003; S100A9 7-fold, p = 0.003; S100A12 28-fold, p = 0.01) compared to placebo (S100A8 2-fold, p = 0.01; S100A9 1.4-fold, p = 0.4; S100A12 5-fold, p = 0.06). In an independent evoked endotoxemia study, calgranulin gene expression correlated with the systemic inflammatory response. Through in vivo and in vitro interrogation we highlight differential responses in adipocytes and mononuclear cells during inflammation, with n-3 PUFA leading to increased calgranulin expression in adipose, but decreased expression in circulating cells. In conclusion, we present a novel relationship between n-3 PUFA anti-inflammatory action in vivo and cell-specific modulation of calgranulin expression during innate immune activation.

Adipose tissue RNASeq reveals novel gene-nutrient interactions following n-3 PUFA supplementation and evoked inflammation in humans.

Dietary consumption of long-chain omega-3 polyunsaturated fatty acids (n-3 PUFA) may protect against cardiometabolic disease through modulation of systemic and adipose inflammation. However, it is often difficult to detect the subtle effects of n-3 PUFA on inflammatory biomarkers in traditional intervention studies. We aimed to identify novel n-3 PUFA modulated gene expression using unbiased adipose transcriptomics during evoked endotoxemia in a clinical trial of n-3 PUFA supplementation. We analyzed adipose gene expression using RNA sequencing in the fenofibrate and omega-3 fatty acid modulation of endotoxemia (FFAME) trial of healthy individuals at three timepoints: before and after n-3 PUFA supplementation (n=8; 3600mg/day EPA/DHA) for 6weeks compared with placebo (n=6), as well as during a subsequent evoked inflammatory challenge (lipopolysaccharide 0.6ng/kg i.v.). As expected, supplementation with n-3 PUFA vs. placebo alone had only modest effects on adipose tissue gene expression, e.g., increased expression of immediate early response IER2. In contrast, the transcriptomic response to evoked endotoxemia was significantly modified by n-3 PUFA supplementation, with several genes demonstrating significant n-3 PUFA gene-nutrient interactions, e.g., enhanced transcriptional responses in specific immune genes IER5L, HES1, IL1RN, CCL18, IL1RN, IL7R, IL8, CCL3 and others. These data highlight potential mechanisms whereby n-3 PUFA consumption may enhance the immune response to an inflammatory challenge. In conclusion, unbiased transcriptomics during evoked inflammation reveals novel immune modulating functions of n-3 PUFA nutritional intervention in a dynamic pathophysiological setting.

Bioactive products formed in humans from fish oils.

Resolvins, maresins, and protectins can be formed from fish oils. These specialized pro-resolving mediators (SPMs) have been implicated in the resolution of inflammation. Synthetic versions of such SPMs exert anti-inflammatory effects in vitro and when administered to animal models. However, their importance as endogenous products formed in sufficient amounts to exert anti-inflammatory actions in vivo remains speculative. We biased our ability to detect SPMs formed in healthy volunteers by supplementing fish oil in doses shown previously to influence blood pressure and platelet aggregation under placebo-controlled conditions. Additionally, we sought to determine the relative formation of SPMs during an acute inflammatory response and its resolution, evoked in healthy volunteers by bacterial lipopolysaccharide (LPS). Bioactive lipids, enzymatic epoxyeicosatrienoic acids (EETs), and free radical-catalyzed prostanoids [isoprostanes (iPs)] formed from arachidonic acid and the fish oils, served as comparators. Despite the clear shift from ω-6 to ω-3 EETs and iPs, we failed to detect a consistent signal, in most cases, of SPM formation in urine or plasma in response to fish oil, and in all cases in response to LPS on a background of fish oil. Our results question the relevance of these SPMs to the putative anti-inflammatory effects of fish oils in humans.

Omega-3 PUFA supplementation and the response to evoked endotoxemia in healthy volunteers.

SCOPE: Fish oil-derived n-3 PUFA may improve cardiometabolic health through modulation of innate immunity. However, findings in clinical studies are conflicting. We hypothesized that n-3 PUFA supplementation would dose-dependently reduce the systemic inflammatory response to experimental endotoxemia in healthy humans. METHODS AND RESULTS: The Fenofibrate and omega-3 Fatty Acid Modulation of Endotoxemia (FFAME) study was an 8-wk randomized double-blind trial of placebo or n-3 PUFA supplementation (Lovaza 465 mg eicosapentaenoic acid (EPA) + 375 mg docosahexaenoic acid (DHA)) at "low" (1/day, 900 mg) or "high" (4/day, 3600 mg) dose in healthy individuals (N = 60; age 18-45; BMI 18-30; 43% female; 65% European-, 20% African-, 15% Asian-ancestry) before a low-dose endotoxin challenge (LPS 0.6 ng/kg intravenous bolus). The endotoxemia-induced temperature increase was significantly reduced with high-dose (p = 0.03) but not low-dose EPA + DHA compared to placebo. Although there was no statistically significant impact of EPA + DHA on individual inflammatory responses (tumor necrosis factor-α (TNF-α), IL-6, monocyte chemotactic protein (MCP-1), IL-1 receptor agonist (IL-1RA), IL-10, C-reactive protein (CRP), serum amyloid A (SAA)), there was a pattern of lower responses across all biomarkers with high-dose (nine of nine observed), but not low-dose EPA + DHA. CONCLUSION: EPA + DHA at 3600 mg/day, but not 900 mg/day, reduced fever and had a pattern of attenuated LPS induction of plasma inflammatory markers during endotoxemia. Clinically and nutritionally relevant long-chain n-3 PUFA regimens may have specific, dose-dependent, anti-inflammatory actions.

NOS3 gene polymorphisms are associated with risk markers of cardiovascular disease, and interact with omega-3 polyunsaturated fatty acids.

OBJECTIVE: Omega-3 polyunsaturated fatty acids (n-3 PUFA) may protect against the development of cardiovascular disease (CVD). Genotype at key genes such as nitric oxide synthase (NOS3) may determine responsiveness to fatty acids. Gene-nutrient interactions may be important in modulating the development of CVD, particularly in high-risk individuals with the metabolic syndrome (MetS). METHODS: Biomarkers of CVD risk, plasma fatty acid composition, and NOS3 single nucleotide polymorphism (SNP) genotype (rs11771443, rs1800783, rs1800779, rs1799983, rs3918227, and rs743507) were determined in 450 individuals with the MetS from the LIPGENE dietary intervention cohort. The effect of dietary fat modification for 12 weeks on metabolic indices of the MetS was determined to understand potential NOS3 gene-nutrient interactions. RESULTS: Several markers of inflammation and dyslipidaemia were significantly different between the genotype groups. A significant gene-nutrient interaction was observed between the NOS3 rs1799983 SNP and plasma n-3 PUFA status on plasma triacylglycerol (TAG) concentrations. Minor allele carriers (AC+AA) showed an inverse association with significantly higher plasma TAG concentrations in those with low plasma n-3 PUFA status and vice versa but the major allele homozygotes (CC) did not. Following n-3 PUFA supplementation, plasma TAG concentrations of minor allele carriers of rs1799983 were considerably more responsive to changes in plasma n-3 PUFA, than major allele homozygotes. CONCLUSIONS: Carriers of the minor allele at rs1799983 in NOS3 have plasma TAG concentrations which are more responsive to n-3 PUFA. This suggests that these individuals might show greater beneficial effects of n-3 PUFA consumption to reduce plasma TAG concentrations.

Gene-nutrient interactions in the metabolic syndrome: single nucleotide polymorphisms in ADIPOQ and ADIPOR1 interact with plasma saturated fatty acids to modulate insulin resistance.

BACKGROUND: Progression of the metabolic syndrome (MetS) is determined by genetic and environmental factors. Gene-environment interactions may be important in modulating the susceptibility to the development of MetS traits. OBJECTIVE: Gene-nutrient interactions were examined in MetS subjects to determine interactions between single nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and its receptors (ADIPOR1 and ADIPOR2) and plasma fatty acid composition and their effects on MetS characteristics. DESIGN: Plasma fatty acid composition, insulin sensitivity, plasma adiponectin and lipid concentrations, and ADIPOQ, ADIPOR1, and ADIPOR2 SNP genotypes were determined in a cross-sectional analysis of 451 subjects with the MetS who participated in the LIPGENE (Diet, Genomics, and the Metabolic Syndrome: an Integrated Nutrition, Agro-food, Social, and Economic Analysis) dietary intervention study and were repeated in 1754 subjects from the LIPGENE-SU.VI.MAX (SUpplementation en VItamines et Minéraux AntioXydants) case-control study (http://www.ucd.ie/lipgene). RESULTS: Single SNP effects were detected in the cohort. Triacylglycerols, nonesterified fatty acids, and waist circumference were significantly different between genotypes for 2 SNPs (rs266729 in ADIPOQ and rs10920533 in ADIPOR1). Minor allele homozygotes for both of these SNPs were identified as having degrees of insulin resistance, as measured by the homeostasis model assessment of insulin resistance, that were highly responsive to differences in plasma saturated fatty acids (SFAs). The SFA-dependent association between ADIPOR1 rs10920533 and insulin resistance was replicated in cases with MetS from a separate independent study, which was an association not present in controls. CONCLUSIONS: A reduction in plasma SFAs could be expected to lower insulin resistance in MetS subjects who are minor allele carriers of rs266729 in ADIPOQ and rs10920533 in ADIPOR1. Personalized dietary advice to decrease SFA consumption in these individuals may be recommended as a possible therapeutic measure to improve insulin sensitivity. This trial was registered at clinicaltrials.gov as NCT00429195.

Complement component 3 polymorphisms interact with polyunsaturated fatty acids to modulate risk of metabolic syndrome.

BACKGROUND: Complement component 3 (C3) is a novel determinant of the metabolic syndrome (MetS). Gene-nutrient interactions with dietary fat may affect MetS risk. OBJECTIVES: The objectives were to determine the relation between C3 polymorphisms and MetS and whether interaction with plasma polyunsaturated fatty acids (PUFAs), a biomarker of dietary PUFA, modulate this relation. DESIGN: C3 polymorphisms (rs11569562, rs2250656, rs1047286, rs2230199, rs8107911, rs344548, rs344550, rs2241393, rs7257062, rs163913, and rs2230204), biochemical measurements, and plasma fatty acids were measured in the LIPGENE-SUpplementation en VItamines et Minéraux AntioXydants (SU.VI.MAX) study in MetS cases and matched controls (n = 1754). RESULTS: Two single nucleotide polymorphisms were associated with MetS. rs11569562 GG homozygotes had decreased MetS risk compared with minor A allele carriers [odds ratio (OR): 0.53; 95% CI: 0.35, 0.82; P = 0.009], which was augmented by high plasma PUFA status (OR: 0.32; 95% CI: 0.11, 0.93; P = 0.04). GG homozygotes had lower C3 concentrations than those in AA homozygotes (P = 0.03) and decreased risk of hypertriglyceridemia compared with A allele carriers (OR: 0.54; 95% CI: 0.34, 0.92; P = 0.02), which was further ameliorated by an increase in long-chain n-3 (omega-3) PUFAs (OR: 0.46; 95% CI: 0.22, 0.97; P = 0.04) or a decrease in n-6 PUFAs (OR: 0.32; CI: 0.16, 0.62; P = 0.002). rs2250656 AA homozygotes had increased MetS risk relative to minor G allele carriers (OR: 1.78; CI: 1.19, 2.70; P = 0.02), which was exacerbated by low n-6 PUFA status (OR: 2.20; CI: 1.09, 4.55; P = 0.03). CONCLUSION: Plasma PUFAs may modulate the susceptibility to MetS that is conferred by C3 polymorphisms, which suggests novel gene-nutrient interactions. This trial was registered at clinicaltrials.gov as NCT00272428.