N-3 polyunsaturated fatty acids and immune cell function

Circulating trans fatty acids are associated with prostate cancer in Ghanaian and American men

The association between fatty acids and prostate cancer remains poorly explored in African-descent populations. Here, we analyze 24 circulating fatty acids in 2934 men, including 1431 prostate cancer cases and 1503 population controls from Ghana and the United States, using CLIA-certified mass spectrometry-based assays. We investigate their associations with population groups (Ghanaian, African American, European American men), lifestyle factors, the fatty acid desaturase (FADS) genetic locus, and prostate cancer. Blood levels of circulating fatty acids vary significantly between the three population groups, particularly trans, omega-3 and omega-6 fatty acids. FADS1/2 germline genetic variants and lifestyle factors explain some of the variation in fatty acid levels, with the FADS1/2 locus showing population-specific associations, suggesting differences in their control by germline genetic factors. All trans fatty acids, namely elaidic, palmitelaidic, and linoelaidic acids, associated with an increase in the odds of developing prostate cancer, independent of ancestry, geographic location, or potential confounders.

Exogenous tetracosahexaenoic acid modifies the fatty acid composition of human primary T lymphocytes and Jurkat T cell leukemia cells contingent on cell type

Tetracosahexaenoic acid (24:6ω-3) is an intermediate in the conversion of 18:3ω-3 to 22:6ω-3 in mammals. There is limited information about whether cells can assimilate and metabolize exogenous 24:6ω-3. This study compared the effect of incubation with 24:6ω-3 on the fatty acid composition of two related cell types, primary CD3+ T lymphocytes and Jurkat T cell leukemia, which differ in the integrity of the polyunsaturated fatty acid (PUFA) biosynthesis pathway. 24:6ω-3 was only detected in either cell type when cells were incubated with 24:6ω-3. Incubation with 24:6ω-3 induced similar increments in the amount of 22:6ω-3 in both cell types and modified the homeoviscous adaptations fatty acid composition induced by activation of T lymphocytes. The effect of incubation with 18:3ω-3 compared to 24:6ω-3 on the increment in 22:6ω-3 was tested in Jurkat cells because primary T cells cannot convert 18:3ω-3 to 22:6ω-3. The increment in the 22:6ω-3 content of Jurkat cells incubated with 24:6ω-3 was 19.5-fold greater than that of cells incubated with 18:3ω-3. Acyl-coA oxidase siRNA knockdown decreased the amount of 22:6ω-3 and increased the amount of 24:6ω-3 in Jurkat cells. These findings show exogenous 24:6ω-3 can be incorporated into primary human T lymphocytes and Jurkat cells and induces changes in fatty acid composition consistent with its conversion to 22:6ω-3 via a mechanism involving peroxisomal β-oxidation that is regulated independently from the integrity of the upstream PUFA synthesis pathway. One further implication is that consuming 24:6ω-3 may be an effective alternative means of achieving health benefits attributed to 20:5ω-3 and 22:6ω-3.

Impact of health and lifestyle food supplements on periodontal tissues and health

According to the new classification, periodontitis is defined as a chronic multifactorial inflammatory disease associated with dysbiotic biofilms and characterized by progressive destruction of the tooth-supporting apparatus. This definition, based on the current scientific evidence, clearly indicates and emphasizes, beside the microbial component dental biofilm, the importance of the inflammatory reaction in the progressive destruction of periodontal tissues. The idea to modulate this inflammatory reaction in order to decrease or even cease the progressive destruction was, therefore, a logical consequence. Attempts to achieve this goal involve various kinds of anti-inflammatory drugs or medications. However, there is also an increasing effort in using food supplements or so-called natural food ingredients to modulate patients' immune responses and maybe even improve the healing of periodontal tissues. The aim of this chapter of Periodontology 2000 is to review the evidence of various food supplements and ingredients regarding their possible effects on periodontal inflammation and wound healing. This review may help researchers and clinicians to evaluate the current evidence and to stimulate further research in this area.

Comparative transcriptome analysis reveals ectopic delta-5 and delta-6 desaturases enhance protective gene expression upon Vibrio vulnificus challenge in Tilapia (Oreochromis niloticus)

Background

Tilapia (Oreochromis niloticus) cultures are frequently infected by Vibrio vulnificus, causing major economic losses to production units. Previously, tilapia expressing recombinant delta-5 desaturase and delta-6 desaturase (D56) were found to be resistant to V. vulnificus infection. In this report, we profile the D56-mediated molecular changes underlying this resistance in tilapia. A comparative transcriptome analysis was performed on V. vulnificus-infected wild-type and D56-transgenic tilapia using Illumina’s sequencing-by-synthesis approach. Gene enrichment analysis on differentially expressed unigenes was performed, and the expression patterns were validated by real-time PCR.

Results

Comparative transcriptome analysis was performed on RNA-sequence profiles obtained from wild-type and D56-transgenic tilapia at 0, 6 and 24 h post-infection with V. vulnificaus. GO and KEGG gene enrichment analyses showed that D56 regulates several pathways and genes, including fatty acid (FA) metabolism associated, and inflammatory and immune response. Expression of selected FA metabolism-associated, inflammatory and immune responsive genes was validated by qPCR. The inflammatory and immune responsive genes that are modulated by FA-associated D56 likely contribute to the enhanced resistance against V. vulnificus infection in Tilapia.

Conclusions

Transcriptome profiling and filtering for two-fold change variation showed that 3795 genes were upregulated and 1839 genes were downregulated in D56-transgenic tilapia. These genes were grouped into pathways, such as FA metabolism, FA elongation, FA biosynthesis, biosynthesis of unsaturated FA, FA degradation, inflammation, immune response, and chemokines. FA-associated genes and immune-related genes were modulated by D56 at 6 h and 24 h post infection with V. vulnificus. The expression patterns of FA-related genes, inflammatory genes, antimicrobial peptide genes and immune responsive genes at 0, 3, 6, 12, 24 and 48 h post-infection suggests these genes are involved in the enhanced resistance of D56 transgenic tilapia to V. vulnificus.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07521-5.

Fatty Acid Mediators in the Tumor Microenvironment

Patients with cancer frequently overexpress inflammatory cytokines with an associated neutrophilia both of which may be downregulated by diets with high omega-3 polyunsaturated fatty acids (ω-3 PUFA). The anti-inflammatory activity of dietary ω-3 PUFA has been suggested to have anticancer properties and to improve survival of cancer patients. Currently, the majority of dietary research efforts do not differentiate between obesity and dietary fatty acid consumption as mediators of inflammatory cell expansion and tumor microenvironmental infiltration, initiation, and progression. In this chapter, we discuss the relationships between dietary lipids, inflammation, neoplasia and strategies to regulate these relationships. We posit that dietary composition, notably the ratio of ω-3 vs. ω-6 PUFA, regulates tumor initiation and progression and the frequency and sites of metastasis that, together, impact overall survival (OS). We focus on three broad topics: first, the role of dietary lipids in chronic inflammation and tumor initiation, progression, and regression; second, lipid mediators linking inflammation and cancer; and third, dietary lipid regulation of murine and human tumor initiation, progression, and metastasis.

The Influence of Diet and Obesity on Gene Expression in SLE

This review provides an overview of the known effects of diet, obesity, and the intake of different nutrients on systemic lupus erythematosus (SLE). It summarizes and discusses the studies in rodents that identified how different diets can regulate gene expression in the disease, together with a description of the effects of diet on lupus patients’ inflammatory state and disease severity. The identification of selected dietary candidates that can modulate SLE onset and progression is analyzed in relation to possible targeted approaches that could ultimately ameliorate the management and prognosis of this disease.

Influence of exercise and dietary omega-3 oil supplementation on interleukin 1-Ra serum concentrations in Standardbred horses

In this study, the influence of fish oil eicosapentaenoic acid and docosahexaenoic acid supplementation on serum interleukin-1 receptor antagonist (IL-1Ra) concentrations was evaluated in horses subjected to a regular racing program. IL-1Ra is an anti-inflammatory protein. It binds to IL-1 receptors blocking the attachment of pro-inflammatory cytokines. Ten regularly trained Standardbred horses (6 geldings and 4 mares, 4–5 years old, mean bodyweight 500 ± 25 kg) were used. They were randomly divided in two equal groups. The experimental group received a supplementation of 70 mL of fish oil (Omega Horse; NBF Lanes, Milan, Italy) every day for 30 days. The control group did not receive any food supplement. Every 10 days (T0, T10, T20 and T30), the horses took part in a 1600-m harness race, and blood samples were collected from each horse before the race and after the race for the measurement of IL-1Ra serum concentration. The application of general linear model-multivariate analysis of variance (ANOVA) showed an effect of race and dietary supplementation. The effect of race on serum IL-1Ra concentrations was observed starting from T20. In particular, serum IL-1Ra showed higher values after the race in both groups at T20; whereas at T30, serum IL-1Ra values increased in the control group and decreased in the experimental group. The results obtained in the present study suggest that submaximal exercise induces an increase of IL-1Ra serum concentration after 20 days of a racing program. Fish oil supplementation had a positive effect on post-exercise response of serum IL-1Ra concentration compared with the unsupplemented control group, suggesting dietary fish oil reduces the response to inflammatory processes induced by physical activity.

Immune regulation and anti-cancer activity by lipid inflammatory mediators

Rodent and clinical studies have documented that myeloid cell infiltration of tumors is associated with poor outcomes, neutrophilia and lymphocytopenia. This contrasts with increased lymphocyte infiltration of tumors, which is correlated with improved outcomes. Lifestyle parameters, such as obesity and diets with high levels of saturated fat and/or omega (ω)-6 polyunsaturated fatty acids (PUFAs), can influence these inflammatory parameters, including an increase in extramedullary myelopoiesis (EMM). While tumor secretion of growth factors (GFs) and chemokines regulate tumor-immune-cell crosstalk, lifestyle choices also contribute to inflammation, abnormal pathology and leukocyte infiltration of tumors. A relationship between obesity and high-fat diets (notably saturated fats in Western diets) and inflammation, tumor incidence, metastasis and poor outcomes is generally accepted. However, the mechanisms of dietary promotion of an inflammatory microenvironment and targeted drugs to inhibit the clinical sequelae are poorly understood. Thus, modifications of obesity and dietary fat may provide preventative or therapeutic approaches to control tumor-associated inflammation and disease progression. Currently, the majority of basic and clinical research does not differentiate between obesity and fatty acid consumption as mediators of inflammatory and neoplastic processes. In this review, we discuss the relationships between dietary PUFAs, inflammation and neoplasia and experimental strategies to improve our understanding of these relationships. We conclude that dietary composition, notably the ratio of ω-3 vs ω-6 PUFA regulates tumor growth and the frequency and sites of metastasis that together, impact overall survival (OS) in mice.

Pregnancy diet and offspring asthma risk over a 10-year period: the Lifeways Cross Generation Cohort Study, Ireland

OBJECTIVE

The association of maternal pregnancy diet with offspring asthma risk have been reported. However, literature on longitudinal patterns of asthma risk relative to intrauterine nutrient exposure is limited. We aimed to establish whether vegetable, oily fish and vitamin D intake during pregnancy are associated with childhood asthma risk over a 10-year period in the Irish Republic.

DESIGN

Mother-child pairs (n=897) from the Lifeways prospective birth cohort, with data on nutrient intake during pregnancy and asthma status, respectively, were eligible for inclusion in the analysis. Data on socioeconomic and morbidity indicators over 10 years of follow-up on mothers and the index child were collected through self-administered questionnaires. Asthma status as diagnosed by the general practitioner at any time point over 10 years was related to maternal vegetable, oily fish and vitamin D intake during pregnancy, while adjusting for gestational age, socioeconomic status, smoking at delivery, breast feeding, season of birth and supplement use. Data were modelled with a marginal model on correlated observations over time within individuals.

RESULTS

In the fully adjusted model, asthma was inversely associated with higher daily average intake of oily fish (OR 0.23 per serving/day, 95% CI 0.04 to 1.41) and of vegetables (OR 0.96 per serving/day, 95% CI 0.88 to 1.05), but the confidence limits overlapped 1. A higher daily vitamin D intake was associated with reduced odds of asthma (OR 0.93 per μg/day, 95% CI 0.89 to 0.98).

CONCLUSION

This analysis suggests higher daily average intake of vitamin D in pregnancy is associated with asthma risk in offspring over the first 10 years of life.

Lipid Inflammatory Mediators in Cancer Progression and Therapy

Rodent and clinical studies have documented that myeloid cell infiltration of tumors is associated with neutrophilia, lymphocytopenia and poor patient outcomes. This contrasts with lymphocyte infiltration of tumors, which is associated with improved outcomes. Lifestyle parameters such as high fat diet s and omega (ω)-6 polyunsaturated fatty acids (PUFA) intake may influence these inflammatory parameters including extramedullary myelopoiesis that can contribute to a metastatic "niche". While, tumor secretion of growth factors (GFs) and chemokines regulate tumor-immune-cell crosstalk, in this chapter, we also emphasize how lifestyle choices, including, obesity, high-fat and high ω-6 PUFA dietary content, contribute to inflammation and myeloid cell infiltration of tumors. A relationship between obesity and high-fat diets (notably the saturated fats in Western diets) and tumor incidence, metastasis, and poor outcomes is generally accepted. However, the mechanisms of dietary promotion of inflammatory microenvironments and targeted drugs to inhibit the clinical sequel remain an unmet challenge. One approach, modification of dietary intake may have a preventative or therapeutic approach to regulate tumor-associated inflammation and remains an attractive, but little studied intervention.

Natural product derived immune-regulatory agents

We can now declare that the clinical goal of immune intervention as a therapeutic strategy for neoplastic, infectious, autoimmune and inflammatory diseases, has been achieved and in many instances obtained regulatory approval. Although, interest in and optimism for this approach has fluctuated, in the last 20years, immunotherapy has progressed from trials with crude microbial mixtures and extracts to the sophisticated use of pure cultured bacterial, synthetized active moieties identified from crude extracts, analogues therefrom and agonists and antagonists identified during screening resulting in reproducible pharmacologically active compounds with multiple mechanisms of action. Our current understanding of the mechanism of action for immunoregulatory agents contributes to the future discovery of improved strategies to use these and future immunotherapies. In this review we have identified and discussed, those drugs that have been approved and or are in clinical development as immunoregulatory agents, emphasizing those derived from or associated with natural product.

Temporal changes in human skeletal muscle and blood lipid composition with fish oil supplementation

The aim of this study was to examine changes in the lipid profile of red blood cells and muscle tissue along with the expression of anabolic signalling proteins in human skeletal muscle. Following a 2-week control period, 10 healthy male participants consumed 5 g d(-1) of fish oil (FO) for 4 weeks. Muscle biopsies and venous blood samples were collected in the fasted state 2 weeks prior (W-2) and immediately before (W0) the initiation of FO supplementation for internal control. Muscle biopsies and venous blood samples were again obtained at week 1 (W1), 2 (W2) and 4 (W4) during FO supplementation for assessment of changes in lipid composition and expression of anabolic signalling proteins. There was no change in the composition of any lipid class between W-2 and W0 confirming control. Following FO supplementation n-3 polyunsaturated fatty acid (n-3 PUFA) muscle lipid composition was increased from W0 to W2 and continued to rise at W4. n-3 PUFA blood lipid composition was increased from W0 to W1 and remained elevated for the remaining time points. Total protein content of focal adhesion kinase (FAK) increased from W0 to W4 whereas total mechanistic target of rapamycin (mTOR) was increased from W0 at W1 with no further significant increases at W2 and W4. These data show that FO supplementation results in discordant changes in the n-3 PUFA composition of skeletal muscle compared to blood that is associated with increases in total FAK content.

Dietary long chain n-3 polyunsaturated fatty acids prevent allergic sensitization to cow's milk protein in mice

BACKGROUND

Cow's milk allergy is one of the most common food allergies in children and no treatment is available. Dietary lipid composition may affect the susceptibility to develop allergic disease.

OBJECTIVE

Assess whether dietary supplementation with long chain n-3 polyunsaturated fatty acids (n-3 LCPUFA) prevents the establishment of food allergy.

METHODS

Mice were fed a control or fish oil diet before and during oral sensitization with whey. Acute allergic skin response, serum immunoglobulins as well as dendritic cell (DC) and T cell subsets in mesenteric lymph nodes (MLN), spleen and/or small intestine were assessed.

RESULTS

The acute allergic skin response was reduced by more than 50% in sensitized mice fed the fish oil diet compared to the control diet. In addition, anti-whey-IgE and anti-whey-IgG1 levels were decreased in the fish oil group. Serum transfer confirmed that the Th2-type humoral response was suppressed since sera of fish oil fed sensitized mice had a diminished capacity to induce an allergic effector response in naïve recipient mice compared to control sera. Furthermore, the acute skin response was diminished upon passive sensitization in fish oil fed naïve recipient mice. In addition, the percentage of activated Th1 cells was reduced by fish oil in spleen and MLN of sham mice. The percentage of activated Th2 cells was reduced in both sham- and whey-sensitized mice. In contrast, whey-sensitized mice showed an increased percentage of CD11b+CD103+CD8α- DC in MLN in association with enhanced FoxP3+ regulatory T cells (Treg) in spleen and intestine of fish oil fed whey-sensitized mice compared to sham mice.

CONCLUSIONS AND CLINICAL RELEVANCE

Dietary n-3 LCPUFA largely prevented allergic sensitization in a murine model for cow's milk allergy by suppressing the humoral response, enhancing local intestinal and systemic Treg and reducing acute allergic symptoms, suggesting future applications for the primary prevention of food allergy.

Fish oil supplementation augments post-exercise immune function in young males

PURPOSE

Fish oils and related fatty acid components have anti-inflammatory properties, with beneficial effects against various disorders such as cardiovascular disease. A single bout of exercise can alter immune function. However, the effects of fish oil on immune function after a single bout of exercise are currently unknown. This study investigated the effect of supplementation with fish oil on the immune response to an acute bout of endurance exercise.

METHODS

Sixteen male subjects underwent a six week double blind randomised placebo controlled supplementation trial involving two groups (fish oil or placebo oil, 3g/day). They attended for two visits, the first involving a maximal exercise test and the second involving a 1-h bout of endurance exercise on a cycle ergometer at 70% (V)O(2peak). Blood samples were taken pre-supplementation, pre-exercise (post-supplementation), immediately, 1 and 3h post-exercise. Samples were analysed for plasma IL-6, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and cortisol; peripheral blood mononuclear cell (PBMC) IL-2, IL-4 and IFN-γ production; neutrophil phagocytosis/oxidative burst; and natural killer (NK) cell cytotoxic activity.

RESULTS

Post-supplementation EPA concentration was increased (P=0.0127) in the fish oil group. At 3h post-exercise PBMC IL-2 (P=0.0067) and NK cell activity (P=0.0163) was greater in the fish oil compared with the control group. However, PBMC IL-4 and IFN-γ productions, plasma IL-6 and cortisol concentrations, as well as neutrophil activity were unaffected by fish oil supplementation.

CONCLUSION

The current study demonstrates that fish oil supplementation reduces increases PBMC IL-2 production and NK cell cytotoxic activity in the recovery period after exercise.

n-3 Long-chain PUFA reduce allergy-related mediator release by human mast cells in vitro via inhibition of reactive oxygen species

Increased n-6 and reduced n-3 long-chain PUFA (LC-PUFA) intake in Western diets may contribute to the increased prevalence of allergic diseases. Key effector cells in allergy are mast cells (MC). The aim of the present study was to investigate the effects of n-6 v. n-3 LC-PUFA on MC phenotype. Human MC lines (LAD2 and HMC-1) were incubated for 24 h with either arachidonic acid (AA, n-6 LC-PUFA) or the n-3 LC-PUFA EPA or DHA. The effects of these three LC-PUFA on degranulation, mediator secretion and reactive oxygen species (ROS) generation were assessed. ROS, mitogen-activated protein kinase (MAPK) or NF-κB inhibitors were used to unravel signalling pathways involved in cytokine secretion. AA, EPA or DHA did not reduce IgE-mediated degranulation by LAD2 cells. However, AA increased PGD₂ and TNF-α secretion by ionomycin/phorbol 12-myristate 13-acetate-stimulated HMC-1, whereas EPA and DHA more prominently inhibited IL-4 and IL-13 secretion. Suppression of IL-4 and IL-13 release by LC-PUFA correlated with reduced ROS generation. IL-4 and IL-13 release by activated HMC-1 was abrogated using ROS inhibitors. Inhibition of MAPK signalling, but not NF-κB, downstream of ROS reduced IL-13 secretion by activated HMC-1. Combined incubation of EPA or DHA with MAPK inhibitors further suppressed IL-13 secretion. In conclusion, the n-6 LC-PUFA AA enhanced pro-inflammatory mediator production by MC, while the n-3 LC-PUFA EPA as well as DHA more effectively suppressed ROS generation and IL-4 and IL-13 release. This suggests that dietary supplementation with EPA and/or DHA may alter the MC phenotype, contributing to a reduced susceptibility to develop and sustain allergic disease.

Perspectives on the use of marine and freshwater hydrobiont oils for development of drug delivery systems

Marine foods represent a unique source of poly-unsaturated fatty acids (PUFA) of the omega-3 (n-3) family. Today it is generally accepted that fish oil is important in a healthy and balanced omnivorous human diet. This favorable health perception of fish oil is however troubled by the high level of PUFA oxidation and low absorption in the gastro-intestinal tract. In this work we present and described various types of delivery systems which are used to improve PUFA and fish oil availability and oxidative stability.

Lyprinol reduces inflammation and improves lung function in a mouse model of allergic airways disease

BACKGROUND

Asthma is an inflammatory airway disease that is characterized by an influx of eosinophils to the lungs, mucus hypersecretion and T helper type 2 cytokine production. Recent dietary changes, including a decreased ω-3 polyunsaturated fatty acid (PUFA) intake, may have contributed to increased asthma rates and dietary supplementation with marine oil could have clinical benefits.

OBJECTIVE

To assess the effects of dietary supplementation with ω-3 PUFAs on allergic inflammation and lung function using a mouse model of ovalbumin (OVA)-induced allergic airway disease (AAD).

METHODS

BALB/c mice received a daily supplement of either fish oil (rich in ω-3 PUFA) or lyprinol (a complex mixture of various marine lipids plus vitamin E and olive oil) before and during AAD. The effects of supplementation on AAD were assessed.

RESULTS

Lyprinol but not fish oil treatment reduced eosinophil influx into the bronchoalveolar lavage fluid, the lung tissue surrounding the airways and the blood, decreased mucus hypersecretion in the lung and reduced airway hyperresponsiveness (AHR). The effects of lyprinol were not associated with changes in serum IgG1 or IgG2a, or the release of IL-4, IL-5, IL-13 and IFN-γ.

CONCLUSIONS

Lyprinol suppresses the development of allergic inflammation and AHR in AAD. The therapeutic potential of dietary supplementation with lyprinol for asthma warrants further investigation.

Interaction of early diet and the development of the immune system

The present review focuses on the specific effects of nutrients on the development of the immune system in early life. There is a big gap regarding the specific mechanisms that regulate immunity at the intestinal level and their impact in the systemic immune function. For this reason, during the last few years there has been great interest in ascertaining the mechanisms that regulate the intestinal immune function, as well as to understand how specific nutrients interact with the gut-associated lymphoid tissue. We have reviewed this topic with special emphasis on how human milk, and its components, influence the early development of intestinal immunity in breast-fed infants compared with formula-fed infants. Interactions between nutrients and intestinal microbiota have also been reviewed. Some micronutrients such as nucleotides and gangliosides, which are present in human milk and also in most foods, are able to influence immune functionality at very low concentrations. The specific action of these micronutrients on some parameters of immunity, as well as their potential mechanisms of action, have been considered in detail. However, there are limited data on how other specific nutrients, namely protein and non-protein N-containing compounds, lipids, carbohydrates, and others, such as minerals, vitamins, fibre, non-nutritional dietary compounds (flavonoids, carotenoids, phyto-oestrogens, etc), influence immunity. In the present review we have provided data regarding the potential effects of these compounds on the immune response in early life. The increasing use of functional foods by the public to improve their general health and prevent the incidence of chronic diseases has become a major area of interest within the nutrition community. Of the many functional foods available, probiotics have been most studied in infancy and childhood, particularly with regard to the prevention of allergic diseases. Infant formulae and fermented milks containing large quantities of probiotics are produced and consumed by Europeans and in other industrialized countries. In the present review we cover the clinical effects of probiotics in preventing disease during early life, as well as the potential mechanisms of interaction between probiotics and the gastrointestinal tract.

Fish oil-fed mice have impaired resistance to influenza infection

Dietary fish oils, rich in (n-3) PUFA, including eicosapentaenoic acid and docosahexaenoic acid, have been shown to have antiinflammatory properties. Although the antiinflammatory properties of fish oil may be beneficial during a chronic inflammatory illness, the same antiinflammatory properties can suppress the inflammatory responses necessary to combat acute viral infection. Given that (n-3) fatty acid-rich fish oil supplementation is on the rise and with the increasing threat of an influenza pandemic, we tested the effect of fish oil feeding for 2 wk on the immune response to influenza virus infection. Male C57BL/6 mice fed either a menhaden fish oil/corn oil diet (4 g fish oil:1 g corn oil, wt:wt at 5 g/100 g diet) or a control corn oil diet were infected with influenza A/PuertoRico/8/34 and analyzed for lung pathology and immune function. Although fish oil-fed mice had lower lung inflammation compared with controls, fish oil feeding also resulted in a 40% higher mortality rate, a 70% higher lung viral load at d 7 post infection, and a prolonged recovery period following infection. Although splenic natural killer (NK) cell activity was suppressed in fish oil-fed mice, lung NK activity was not affected. Additionally, lungs of infected fish oil-fed mice had significantly fewer CD8+ T cells and decreased mRNA expression of macrophage inflammatory protein-1-alpha, tumor necrosis factor-alpha, and interleukin-6. These results suggest that the antiinflammatory properties of fish oil feeding can alter the immune response to influenza infection, resulting in increased morbidity and mortality.

Glucose metabolism by lymphocytes, macrophages, and tumor cells from Walker 256 tumor-bearing rats supplemented with fish oil for one generation

Here we investigated the effect of lifelong supplementation of the diet with coconut fat (CO, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids) on tumor growth and lactate production from glucose in Walker 256 tumor cells, peritoneal macrophages, spleen, and gut-associated lymphocytes. Female Wistar rats were supplemented with CO or FO prior to mating and then throughout pregnancy and gestation and then the male offspring were supplemented from weaning until 90 days of age. Then they were inoculated subcutaneously with Walker 256 tumor cells. Tumor weight at 14 days in control rats (those fed standard chow) and CO supplemented was approximately 30 g. Supplementation of the diet with FO significantly reduced tumor growth by 76%. Lactate production (nmol h(-1) mg(-1) protein) from glucose by Walker 256 cells in the group fed regular chow (W) was 381.8 +/- 14.9. Supplementation with coconut fat (WCO) caused a significant reduction in lactate production by 1.6-fold and with fish oil (WFO) by 3.8-fold. Spleen lymphocytes obtained from W and WCO groups had markedly increased lactate production (553 +/- 70 and 635 +/- 150) when compared to non-tumor-bearing rats ( approximately 260 +/- 30). FO supplementation reduced significantly the lactate production (297 +/- 50). Gut-associated lymphocytes obtained from W and WCO groups increased lactate production markedly (280 +/- 31 and 276 +/- 25) when compared to non-tumor-bearing rats ( approximately 90 +/- 18). FO supplementation reduced significantly the lactate production (168 +/- 14). Lactate production by peritoneal macrophages was increased by tumor burden but there was no difference between the groups fed the various diets. Lifelong consumption of FO protects against tumor growth and modifies glucose metabolism in Walker tumor cells and lymphocytes but not in macrophages.

Nitro-fatty acid metabolome: saturation, desaturation, beta-oxidation, and protein adduction

Nitrated derivatives of fatty acids (NO2-FA) are pluripotent cell-signaling mediators that display anti-inflammatory properties. Current understanding of NO2-FA signal transduction lacks insight into how or if NO2-FA are modified or metabolized upon formation or administration in vivo. Here the disposition and metabolism of nitro-9-cis-octadecenoic (18:1-NO2) acid was investigated in plasma and liver after intravenous injection in mice. High performance liquid chromatography-tandem mass spectrometry analysis showed that no 18:1-NO2 or metabolites were detected under basal conditions, whereas administered 18:1-NO2 is rapidly adducted to plasma thiol-containing proteins and glutathione. NO2-FA are also metabolized via beta-oxidation, with high performance liquid chromatography-tandem mass spectrometry analysis of liver lipid extracts of treated mice revealing nitro-7-cis-hexadecenoic acid, nitro-5-cis-tetradecenoic acid, and nitro-3-cis-dodecenoic acid and corresponding coenzyme A derivatives of 18:1-NO2 as metabolites. Additionally, a significant proportion of 18:1-NO2 and its metabolites are converted to nitroalkane derivatives by saturation of the double bond, and to a lesser extent are desaturated to diene derivatives. There was no evidence of the formation of nitrohydroxyl or conjugated ketone derivatives in organs of interest, metabolites expected upon 18:1-NO2 hydration or nitric oxide (*NO) release. Plasma samples from treated mice had significant extents of protein-adducted 18:1-NO2 detected by exchange to added beta-mercaptoethanol. This, coupled with the observation of 18:1-NO2 release from glutathione-18:1-NO2 adducts, supports that reversible and exchangeable NO2-FA-thiol adducts occur under biological conditions. After administration of [3H]18:1-NO2, 64% of net radiolabel was recovered 90 min later in plasma (0.2%), liver (18%), kidney (2%), adipose tissue (2%), muscle (31%), urine (6%), and other tissue compartments, and may include metabolites not yet identified. In aggregate, these findings show that electrophilic FA nitroalkene derivatives (a) acquire an extended half-life by undergoing reversible and exchangeable electrophilic reactions with nucleophilic targets and (b) are metabolized predominantly via saturation of the double bond and beta-oxidation reactions that terminate at the site of acyl-chain nitration.

Regulation of human lymphocyte proliferation by fatty acids

In the present study, the effect of increasing concentrations of palmitic (PA, C16:0), stearic (SA, C18:0), oleic (OA, C18:1, n-9), linoleic (LA, C18:2n-6), docosahexaenoic (DHA, C22:6 n-3) and eicosapentaenoic (EPA, C20:5 n-3) acids on lymphocyte proliferation was investigated. The maximal non-toxic concentrations of these fatty acids for human lymphocytes in vitro were determined. It was also evaluated whether these fatty acids at non-toxic concentrations affect IL-2 induced lymphocyte proliferation and cell cycle progression. OA and LA at 25 microM increased lymphocyte proliferation and at higher concentrations (75 microM and 100 microM) inhibited it. Both fatty acids promoted cell death at 200 microM concentration. PA and SA decreased lymphocyte proliferation at 50 microM and promoted cell death at concentrations of 100 microM and above. EPA and DHA decreased lymphocyte proliferation at 25 and 50 microM being toxic at 50 and 100 microM, respectively. PA, SA, DHA and EPA decreased the stimulatory effect of IL-2 on lymphocyte proliferation, increasing the percentage of cells in G1 phase and decreasing the proportion of cells in S and G2/M phases. OA and LA caused an even greater pronounced effect. The treatment with all fatty acids increased neutral lipid accumulation in the cells but the effect was more pronounced with PA and DHA. In conclusion, PA, SA, DHA and EPA decreased lymphocyte proliferation, whereas OA and LA stimulated it at non-toxic concentrations.

Induction and modulation of apoptosis in neonatal monocytes by polyunsaturated fatty acids

Polyunsaturated fatty acids (PUFAs), known modulators of the immune response, are the source of essential fatty acids in total parenteral nutrition-dependent patients. Critically ill infants on TPN have an increased incidence of sepsis, and lipid emulsions depress various immune functions. Recent studies have demonstrated that PUFAs induce apoptosis in various tissue cells in vitro and ex vivo. The susceptibility of neonatal monocytes, as major early effector cells in the host response to sepsis, to PUFA-mediated apoptosis and the mechanisms associated with PUFA-induced apoptosis were investigated. Both n-3 and n-6 PUFAs induced rapid, dose-dependent cell death in purified monocytes. Polyunsaturated fatty acids induced significant activation of upstream caspases 8 and 9 as well as caspase 3. The PUFA treatment resulted in a 4-fold increase in oxidative stress and a loss of monocyte mitochondrial potential compared with carrier controls (P < .05). The addition of cyclosporin, which blocks the development of mitochondrial transition pores, completely abolished the proapoptotic effects of PUFAs. Although Trolox (Sigma Aldrich) reduced PUFA-induced intracellular oxidative stress in neonatal monocytes, apoptosis was not blocked by this potent antioxidant. The data identify PUFAs as potent inducers of monocyte apoptosis, which can occur independently of the induction of oxidative stress, by using a mitochondrial dependent pathway. The TPN-dependent infant may be particularly sensitive to such PUFA effects, having a relatively poor capacity to both use and clear PUFAs.

Argan (Argania spinosa) oil lowers blood pressure and improves endothelial dysfunction in spontaneously hypertensive rats

Traditionally hand-pressed argan oil, obtained from Argania spinosa seeds, is eaten raw in south-west Morocco; its rich composition of tocopherols, MUFA and PUFA make a study of its actions on risk factors for CVD, such as hypertension, interesting. The effects of 7 weeks of treatment with argan oil (10ml/kg) on the blood pressure and endothelial function of spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats were investigated. Systolic blood pressure and heart rate were measured every week by the tail-cuff method and endothelial function was assessed by carbachol (10−8 to 10−4m)-induced relaxations of aortic rings and small mesenteric arteries pre-contracted with phenylephrine. Argan-oil administration reduced the mean blood pressure of SHR after the fifth week of treatment (P<0·05) and increased (P<0·01) the endothelial responses of arteries from SHR. The NO synthase inhibitor, l-N-ω-nitroarginine (3×10−5m) revealed a greater participation of NO in the relaxant effect after the treatment. When cyclooxygenase (COX) was blocked with indomethacin (10−5m), an involvement of COX products in the endothelium-dependent response was characterized. Enzyme immunoassay of thromboxane B2 showed a significant decrease (P<0·05) in the release of thromboxane A2 in both aorta and small mesenteric artery after argan-oil treatment of SHR. Experiments in the presence of the thromboxane A2–prostaglandin H2 receptor antagonist ICI 192, 605 (10−5m) confirmed this result. Results after incubation with the antioxidants superoxide dismutase and catalase suggested that a decreased oxidative stress might contribute to explain the beneficial effects of argan-oil treatment.

Dietary fatty acids influence the appearance of tumour necrosis factor-α receptors on adipocytes following an immune challenge

Rats were fed from weaning on chow supplemented with suet or sunflower oil (10 % (w/w) each). The appearance of receptors for tumour necrosis factor-α on perinodal adipocytes from the popliteal depot following a subcutaneous injection of bacterial lipopolysaccharide was examined. In rats fed on sunflower oil-supplemented chow receptors appeared at a time similar to that described in rats fed unsupplemented chow, but in rats fed on chow supplemented with suet receptor appearance was significantly delayed. The popliteal adipocytes were found to contain different proportions of fatty acids as assessed by GLC. These preliminary results suggest that the fatty acid component of the diet can, by influencing the triacylglycerol-fatty acids within adipocytes, directly alter the time course of an early inflammatory immune response.

Fatty acid intake and the risk of community-acquired pneumonia in U.S. women

OBJECTIVE

Despite substantial progress in the treatment of community-acquired pneumonia, there are limited data on dietary risk factors. Fatty acid intake may influence community-acquired pneumonia risk by modulating the immune system. Our study prospectively examined the association between fatty acid intake and community-acquired pneumonia risk.

METHODS

The study population included 83165 women from the Nurses' Health Study II cohort who were 27 to 44 y old in 1991. The women reported lifestyle habits on biennial questionnaires and dietary intake every 4 y by validated semiquantitative food frequency questionnaires. There were 925 pneumonia cases over 10 y of follow-up. We examined independent associations for six fatty acids using Cox's proportional hazards regression.

RESULTS

Women in the highest quintile of palmitic acid intake had a 54% greater risk of pneumonia compared with those in the lowest quintile (multivariate relative risk 1.54, 95% confidence interval 1.12-2.12, P for trend = 0.002). Oleic acid intake was inversely associated with pneumonia risk (highest quintile multivariate relative risk 0.75, 95% confidence interval 0.55-1.04, P for trend = 0.02). Women in the highest quintile of docosahexanoic acid and eicosapentaenoic acid intake had a 24% greater risk of community-acquired pneumonia than did those in the lowest quintile (multivariate relative risk 1.24, 95% confidence interval 1.00-1.55, P for trend = 0.08). No significant associations were found for linoleic acid, alpha-linolenic acid, or docosahexanoic acid alone.

CONCLUSION

Fatty acid intake may affect the risk of community-acquired pneumonia in young and middle-aged women. Higher dietary intake of palmitic acid and possibly docosahexanoic and eicosapentaenoic acids may increase the risk of community-acquired pneumonia in women, whereas higher oleic acid intake may decrease the risk.

Effect of fish or soybean oil-rich diets on bradykinin, kallikrein, nitric oxide, leptin, corticosterone and macrophages in carrageenan stimulated rats

We have previously demonstrated that both n-3 and n-6 polyunsaturated fatty acids (PUFA)-rich diets decrease the acute inflammatory response partially explained by the high corticosterone basal levels. The present study aimed to determine the effect of hyperlipidic diets (PUFA n-3 or n-6) on phagocytosis, hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) release by macrophages, bradykinin (BK) and NO release in the paw inflammatory perfusate and Kallikrein (KK), corticosterone and leptin blood levels. Hyperlipidic diets decreased H(2)O(2) release from macrophages stimulated by carrageenan or phorbol-miristate-acetate (PMA), NO release from macrophage stimulated by carrageenan, BK and NO release in the edema perfusate, KK plasma levels and the increase of serum leptin after carrageenan stimulus. These data show that both fish and soybean oil-rich diets promote similar alterations on inflammatory mediators of carrageenan edema and a causal association with the anti-inflammatory effect of these diets.

Effect of docosahexaenoic acid-rich fish oil supplementation on human leukocyte function

BACKGROUND

The effect of a docosahexaenoic acid (DHA)-rich fish oil (FO) supplementation on human leukocyte function was investigated.

METHODS

Ten male volunteers were supplemented with 3g/day FO containing 26% eicosapentaenoic acid (EPA, 20:5, n-3) and 54% DHA (22:6, n-3) for 2 months.

RESULTS

FO supplementation changed the fatty acid (FA) composition of leukocytes resulting in an increase of n-3/n-6 ratio from 0.18 to 0.62 in lymphocytes and from 0.15 to 0.70 in neutrophils. DHA-rich FO stimulated an increase in phagocytic activity by 62% and 145% in neutrophils and monocytes, respectively. Neutrophil chemotactic response was increased by 128%. The rate of production of reactive oxygen species by neutrophils was also increased, as it was with lymphocyte proliferation. These changes were partially reversed after a 2-month wash out period. With respect to cytokine production by lymphocytes, interleukin (IL)-4 release was not altered, whereas secretions of IL-10, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were raised. These results are in contrast to those described by others using EPA-rich FO supplementation. Lymphocyte pleiotropic gene expression was analyzed by a macroarray technique. Of the analyzed genes (588 in total), 77 were modified by the supplementation. FO supplementation resulted in up-regulation of 6 genes (GATA binding protein 2, IL-6 signal transducer, transforming growth factor alpha, TNF, heat shock 90kDa protein 1-alpha and heat shock protein 70kDa 1A) and a down regulation of 71 genes (92.2% of total genes changed). The largest functional group of altered genes was that related to signaling pathways (22% of the total modified genes).

CONCLUSIONS

Therefore, although EPA and DHA are members of n-3 FA family, changes in the proportion of DHA and EPA exert different effects on neutrophil, monocyte and lymphocyte function, which may be a result of specific changes in gene expression.

Effects of acute or chronic omega-3 and omega-6 polyunsaturated fatty acid treatment on behavioral, neuroendocrine and cytokine changes elicited by exogenous interleukin-1beta challenge

Chronic omega-3 or omega-6 polyunsaturated fatty acid (n-3; n-6 respectively) treatment attenuated human interleukin-1beta (hIL-1beta; 5.0 microg/kg)-elicited rise of circulating ACTH levels and attenuated the sickness behavior and locomotor suppression elicited by the cytokine. Furthermore, hIL-1beta markedly elevated circulating levels of plasma IL-6, an effect attenuated by n-3, but not n-6 treatment. Such protective effects were not evident upon short-term (3 day) n-3 exposure. These results demonstrate that long-term administration of either n-3 or n-6 confers protection against several neuroendocrinological, immunological and behavioral actions of hIL-1beta challenge, although in general the effects of n-3 were more pronounced.

Conjugated linoleic acid can prevent tumor necrosis factor gene expression by inhibiting nuclear factor binding activity in peripheral blood mononuclear cells from weaned pigs challenged with lipopolysaccharide

Twenty-four weanling barrows were fed corn-soybean diets supplemented with 2% conjugated linolenic acid (CLA) or soybean oil. On day 14 and 21, pigs were injected intraperitoneally with lipopolysaccharide (LPS) or sterile saline. Plasma samples were collected 2h after injection. Peripheral blood mononuclear cells (PBMC) were also collected on day 21, 2 h after injection to determine tumor necrosis factor-alpha (TNF-alpha) production and its mRNA expression. The results indicate that dietary CLA inhibited the production of TNF-alpha by pig PBMC both at the protein and mRNA expression level. In a second experiment, PBMC, collected from a healthy pig, were incubated with either c9,t11-CLA or t10,c12-CLA, or without CLA and stimulated with LPS. Both CLA isomers inhibited LPS-stimulated TNF-alpha production and expression, which may be partially due to inhibition of the binding activity of nuclear factor-kappaB. The t10,c12 isomer was more effective than the c9,t11-CLA isomer in reducing TNF-alpha levels and nuclear factor-kappaB activation.

Improved fatty acid and leukotriene pattern with a novel lipid emulsion in surgical patients

OBJECTIVE

We assessed the effects of a novel lipid emulsion with reduced content of n-6 fatty acids (FA), increased share of MUFA and n-3 FA and supplemental vitamin E on fatty acid and leukotriene pattern in surgical patients.

METHODS

In a double-blind, randomized study 33 patients received isonitrogenous, isocaloric TPN over 5 postoperative days following major abdominal surgery. 19 patients received the new SMOFlipid 20% and 14 patients a standard soybean oil emulsion (Lipovenoes 20%, both Fresenius Kabi), each 1.5 g fat/kg body weight (BW)/d. Routine lipid biochemistry, plasma tocopherol, fatty acid pattern in plasma phospholipids, as well as leukotriene (LT) release in leukocytes were assessed. Additionally, fatty acid pattern in leukocyte and platelet phospholipids were analysed, but results are not presented.

RESULTS

On day 6, plasma alpha-tocopherol (34.2 +/- 10.3 vs. 17.6 +/- 2.9 micromol/L) and, in plasma PL, total n-3 FA were higher (11.1 +/- 1.9 vs. 4.9 +/- 0.9 mol%; p < 0.05) and total n-6 FA lower (23.8 +/- 2.2 vs. 31.8 +/- 1.7 mol%; P < 0.05); the ratio n-3/n-6 FA being elevated (0.5 +/- 0.1 vs. 0.2 +/- 0.0 p < 0.05) with SMOFlipid compared to the soybean oil emulsion. The shares of EPA (3.3+/-1.0 vs. 0.4+/-0.2 mol%; p<0.05) and DHA (6.9 +/- 1.8 vs. 3.7 +/- 0.8 mol%; p < 0.05) were highly increased but that of arachidonic acid (AA) was unchanged with SMOFlipid while the ratio EPA/AA was increased (0.7 +/- 0.2 vs. 0.1 +/- 0.0 p < 0.05). LTB(5) release was enhanced on day 6 (8.1 +/- 5.3 vs. 1.8 +/- 3.8 pmol/10(7) PMN, p < 0.05) and liberation of LTB(4) was lowered, yet not significantly with SMOFlipid (124.0 +/- 51.2 vs. 152.1 +/- 68.8 pmol/10(7) PMN). Length of hospital stay was significantly shorter with SMOFlipid (13.4 +/- 2.0 vs. 20.4 +/- 10.0 days, p < 0.05).

CONCLUSION

Treatment with the new emulsion SMOFlipid is well tolerated and modulates FA and leukotriene pattern suggesting favourable anti-inflammatory effects and further clinical benefits.

Modulation of immune cell function by polyunsaturated fatty acids

The n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential dietary constituents. They are important as a source of energy, as structural components of cell membranes, and as signalling molecules. They have been demonstrated to be potent modulators of the immune response, and research has endeavoured to optimise the ratio of n-3 to n-6 PUFAs in the lipid component of total parenteral nutrition (TPN) to optimise their beneficial effects in the clinical setting. Critically ill neonates on TPN have an increased incidence of sepsis, and additional studies have determined that lipid emulsions depress various elements of cellular immune responses in monocytes, lymphocytes, and neutrophils. It has been proposed that PUFAs may mediate their manifold effects through the modification of eicosanoid production and by directly or indirectly modifying intracellular signal transduction pathways, including the alteration of gene transcription, in various tissues. They are susceptible to lipid peroxidation, and there is evidence that the products of this process may result in cell death by apoptosis, a nonphlogistic homeostatic process of cell deletion. PUFAs have been shown to induce apoptosis in primary lymphocytes, colonic mucosal cells, and various cell lines. Additionally, our laboratory has shown them to be potent inducers of apoptosis in neonatal monocytes. This may represent a novel mechanism whereby PUFAs may modify the immune response.

Effects of different dietary oils on inflammatory mediator generation and fatty acid composition in rat neutrophils

Virgin olive oil (VOO) compared with fish oil (FO) and evening primrose oil (PO) on the ability of stimulated leukocytes to produce inflammatory mediators was investigated in rats. Weaned Wistar rats were fed a basal diet (BD) (2% by weight of corn oil) or diets containing 15% by weight of VOO, PO, or FO. After 8 weeks, glycogen-elicited peritoneal polymorphonuclear leukocytes, mainly neutrophils, were isolated. The calcium-ionophore stimulated neutrophils (2.5 x 10(6) cells/mL) obtained from rats fed the different oils produced a higher release of lysosomal enzymes (beta-glucuronidase, lysozyme, and myeloperoxidase [MPO]) compared with those fed BD. The production of reactive oxygen species (ROS) in response to the stimulant, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), by neutrophils from the VOO group (15.44 nmol of O(2)(-) and 6.56 nmol of H(2)O(2)) was similar to the BD group (12.01 nmol O(2)(-) and 8.49 nmol H(2)O(2)) and significantly lower than the PO (20.90 nmol O(2)(-) and 10.84 nmol H(2)O(2)) and FO (20.93 nmol O(2)(-) and 12.79 nmol H(2)O(2)) groups. The cyclooxygenase-derived eicosanoid production was reduced by the lipid enrichment of the diets. Whereas the generation of prostaglandin E(2) (PGE(2)) was significantly decreased in VOO (5.40 ng/mL), PO (4.95 ng/mL), and FO (1.44 ng/mL) groups compared with BD (8.19 ng/mL), thromboxane B(2) (TXB(2)) reduction was especially significant in neutrophils from the FO diet group (14.67 ng/mL compared with 26.69 ng/mL from BD). These experimental data suggest that FO and PO, as well as VOO, could be considered a valuable strategy in preventing the generation of some inflammatory mediators.

Effects of fish oil supplementation on the performance and the immunological, adrenal, and somatotropic responses of weaned pigs after an Escherichia coli lipopolysaccharide challenge1

Seventy-two crossbred pigs (7.58 +/- 0.30 kg BW) weaned at 28 +/- 3 d of age were used to investigate the effects of fish oil supplementation on pig performance and on immunological, adrenal, and somatotropic responses following an Escherichia coli lipopolysaccharide (LPS) challenge in a 2 x 2 factorial design. The main factors consisted of diet (7% corn oil [CO] or 7% fish oil [FO]) and immunological challenge (LPS or saline). On d 14 and 21, pigs were injected intraperitoneally with either 200 microg/kg BW of LPS or an equivalent amount of sterile saline. Blood samples were collected 3 h after injection for analysis of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), cortisol, growth hormone (GH), and insulin-like growth factor (IGF)-I. On d 2 after LPS challenge, peripheral blood lymphocyte proliferation (PBLP) was determined. Lipopolysaccharide challenge decreased ADG (487 vs. 586 g; P < 0.05) and ADFI (as-fed, 776 vs. 920 g; P < 0.05) from d 14 to 21 and ADG (587 vs. 652 g; P < 0.10) from d 21 to 28. Fish oil improved ADG (554 vs. 520 g; P < 0.10) and ADFI (891 vs. 805 g; P < 0.10) from d 14 to 21. On d 14, LPS challenge x diet interactions were observed for IL-1beta (P < 0.10), PGE2 (P < 0.001), and cortisol (P < 0.05) such that these measurements responded to the LPS challenge to a lesser extent (IL-1beta: 93 vs. 114 pg/mL, P < 0.05; PGE2: 536 vs. 1,285 pg/mL, P < 0.001; cortisol: 143 vs. 206 ng/mL, P < 0.05) in pigs receiving the FO diet than in pigs fed the CO diet. In contrast, among LPS-treated pigs, pigs fed the FO diet had higher IGF-I (155 vs. 101 ng/mL; P < 0.10) than those fed the CO diet. On d 21 among LPS-treated pigs, pigs fed FO had lower IL-1beta (70 vs. 84 pg/mL; P < 0.10) and cortisol (153 vs. 205 ng/mL; P < 0.05) than those fed CO. Pigs fed FO had lower PGE2 (331 vs. 444 pg/mL; P < 0.05) and higher IGF-I (202 vs. 171 ng/mL; P < 0.10) compared with those fed CO. Lipopolysaccharide challenge decreased GH (0.27 vs. 0.33 ng/mL; P < 0.05) on d 14, whereas it had no effect on GH on d 21. During both LPS challenge periods, the challenge increased PBLP when these cells were incubated with 8 (1.46 vs. 1.32; P < 0.10) or 16 microg/mL (1.46 vs. 1.30; P < 0.05) of concanavalin A. Fish oil had no effect on PBLP. These results suggest that FO alters the release of proinflammatory cytokines, which might lead to improved pig performance during an immunological challenge.

Nutrition and inflammatory bowel disease: its relation to pathophysiology, outcome and therapy

Nutritional deficiencies are frequent in patients with ulcerative colitis and Crohn's disease, and negatively influence the outcome of the disease. Growth retardation, osteopenia and thromboembolic phenomena are some of the inflammatory bowel disease complications in which nutritional deficits are involved. Moreover, nutrients can play a role in the pathogenesis of the disease and, in some cases, can be a primary therapeutic tool. Enteral nutrition has proven to play a therapeutic role in Crohn's disease. The nutrient(s) responsible for this effect are not well identified but dietary fat appears to be a major factor. In ulcerative colitis, unabsorbable carbohydrates can modulate the intestinal microbial environment, thus contributing to improve colonic inflammation.

Maternal dietary N-3 fatty acids alter the spleen fatty acid composition and bovine serum albumin-induced wing web swelling in broilers

Effects of maternal dietary polyunsaturated fatty acids (PUFA) on the spleen fatty acid composition and BSA-induced wing web swellings were investigated in broilers. One hundred twenty broiler breeder hens 26 wk of age were randomly assigned to diets containing mainly wheat, corn, soy meal, barley, oat and 5% (wt/wt) added sunflower oil, fish oil, or a mix of sunflower and fish oils (1:1). After 2 wk on the experimental diets, birds were inseminated, eggs were collected and incubated. Progeny chicks were then fed identical diets for 6 wk. The maternal dietary oils affected (P < 0.05) n-6 and n-3 PUFA in the spleens of hatching chicks. After 2 wk, n-6 PUFA did not differ among the groups; n-3 PUFA, docosapentaenoic, and docosahexaenoic (DHA) acids were higher (P < 0.05) in the spleens of broilers from hens fed 2.5 or 5% fish oil. After 4 wk, broilers from hens fed 5% fish oil still had higher levels of DHA (P < 0.05) in their spleens than those from hens fed 5% sunflower oil. The BSA-induced wing web swelling response was suppressed (P < 0.05) by n-3 PUFA in breeder hens. Broilers from hens fed high levels of n-3 PUFA had lower (P < 0.05) wing web swelling reactions to BSA at 2 wk (2.5% fish oil) and 4 wk (2.5 and 5% fish oil). In conclusion, n-3 PUFA in breeder hen diets suppressed the BSA-induced wing web swellings of the hens, increased the spleen n-3 fatty acids (especially DHA), and decreased BSA-induced wing web swellings of progeny up to 4 wk of age.

High omega-3:omega-6 fatty acid ratios in culture medium reduce endometrial-cell survival in combined endometrial gland and stromal cell cultures from women with and without endometriosis

OBJECTIVE

To study the effects of omega-3 and omega-6 polyunsaturated fatty acid (PUFA) on in vitro proliferation of endometrial cells and their production of the cytokine interleukin-8 (IL-8).

DESIGN

In vitro study.

SETTING

Obstetrics and gynecology department, University of Aberdeen.

PATIENT(S)

Women attending an infertility clinic.

INTERVENTION(S)

In vitro cell cultures using culture mediums supplemented with normal and high ratios of omega-3 PUFA and omega-6 PUFA.

MAIN OUTCOME MEASURE(S)

In vitro survival and production of IL-8 by dispersed endometrial cells.

RESULT(S)

In vitro survival of endometrial cells from women with and without endometriosis was significantly reduced in the presence of high omega-3:omega-6 PUFA ratios compared with cells incubated in the absence of fatty acids, in balanced omega-3:omega-6 PUFA ratios, and in high omega-6:omega-3 PUFA ratios. Endometrial cells from women with endometriosis secreted higher concentrations of IL-8, especially in the presence of high omega-3:omega-6 PUFA ratios.

CONCLUSION(S)

omega-3 PUFA may have a suppressive effect on the in vitro survival of endometrial cells and omega-3 PUFA be useful in the management of endometriosis by reducing the inflammatory response and modulating cytokine function.

Fatty acids and immune responses--a new perspective in searching for clues to mechanism

Dietary essential fatty acids are the precursors for eicosanoids. Among the eicosanoids derived from arachidonic acid, prostaglandin (PG) E2 is known to possess immunosuppressive actions. Thus, it has been a prevailing hypothesis that the immuno-modulatory roles of dietary fatty acids are mediated at least in part through the alteration of PG biosynthesis. PGs exert their biological effects through their cognate receptors. There are four subtypes of PGE receptors (EP1, EP2, EP3, and EP4) so far identified. Although the association of EP receptors with G proteins coupled to adenylate cyclase and the mobilization of intracellular calcium are well documented, downstream signaling pathways for these receptors are virtually unknown. Identification of downstream signaling pathways for each subtype of EP receptors and target genes regulated by the activation of the receptor will help with our understanding of the mechanism by which dietary fatty acids affect immune responses through the modulation of PGE2 biosynthesis. Emerging evidence suggests that fatty acids can additionally act as second messengers, regulators of signal transducing molecules or transcription factors. Acylation with long-chain fatty acids can occur on a variety of signaling molecules and can affect their membrane translocation and functions. Dietary fatty acids can alter functional properties of lipid mediators by changing the composition of acyl moieties of these molecules. Evidence accumulated recently indicates that long-chain unsaturated fatty acids and their metabolites bind and activate peroxisome proliferator-activated receptors (PPARs). PPARs are nuclear hormone receptors and transcription factors that regulate the expression of broad arrays of genes involved not only in lipid and glucose metabolism, but also in immune and inflammatory responses. PPARs may therefore be important cellular targets that mediate modulation of immune responses by dietary fatty acids. Together, it becomes clear now that multiple steps in various receptor-mediated signaling pathways can be modulated by dietary fatty acids. It will be a challenging task to quantitatively determine how different fatty acids alter functional properties of multitude of signaling components and final cellular responses. Elucidating the mechanism of actions of fatty acids on receptor-mediated signaling pathways in immuno-competent cells will provide a new insight for understanding the immuno-modulatory roles of dietary fatty acids.

Review: the role of omega 3 fatty acids in intestinal inflammation

The role of polyunsaturated fatty acids (PUFAs) in inflammatory lesions of the intestines is the subject of increasing research. This review begins with a background discussion of the source, elongation, and desaturation of PUFAs, as well as the role they have played in the human diet through evolution. The available data and hypotheses as to how manipulation of PUFAs might effect the various components of the immune system are then provided. Possible mechanisms by which PUFAs result in immunomodulation include alterations in eicosanoid synthesis, membrane fluidity, signal transduction, intraluminal bacteria, and gene expression. Attention is then turned to the known effects that these polyunsaturated fatty acids have on the various individual components of the immune system including lymphocytes, neutrophils, and antigen presenting cells, as well as the immunoregulatory process of apoptosis. Finally, laboratory data on the role of PUFAs in necrotizing enterocolitis, and to a greater extent inflammatory bowel disease, first as demonstrated in animal models of the disease, and second in human studies are then summarized.