Dietary n-3 polyunsaturated fatty acids (PUFAs) present beneficial effects on counteracting inflammation status, displaying a critical anti-inflammatory role and maintaining physiological homeostasis in obesity. The primary objective of this systematic review was to evaluate the effect of n-3 PUFAs intake on the eicosanoid profile of people with obesity and overweight. The search strategy on Embase, Scopus, PubMed, Web of Science, Cochrane Library, Google Scholar and ProQuest was undertaken until November 2019 and updated January 2021. The effect size of n-3 PUFAs on prostaglandins was estimated by Glass's, type 1 in a random-effect model for the meta-analysis. Seven clinical trials met the eligible criteria and a total of 610 subjects were included in this systematic review, and four of seven studies were included in meta-analysis. The intake of n-3 PUFAs promoted an overall reduction in serum pro-inflammatory eicosanoids. Additionally, n-3 PUFAs intake significantly decreased the arachidonic acid COX-derived PG eicosanoid group levels (Glass's Δ −0⋅35; CI −0⋅62, −0⋅07, I2 31⋅48). Subgroup analyses showed a higher effect on periods up to 8 weeks (Glass's Δ −0⋅51; CI −0⋅76, −0⋅27) and doses higher than 0⋅5 g of n-3 PUFAs (Glass's Δ −0⋅46; CI −0⋅72, −0⋅27). Dietary n-3 PUFAs intake contributes to reduce pro-inflammatory eicosanoids of people with obesity and overweight. Subgroup's analysis showed that n-3 PUFAs can reduce the overall arachidonic acid COX-derived PG when adequate dose and period are matched.

The present study aimed to evaluate the inflammatory response, oxidative status and fatty acid deposition in reproductive tissues of cats supplemented with the dried microalgae Schizochytrium spp. (Thraustochytriaceae) as a DHA source. Thirty-seven cats (males, n 21; females, n 16; 11·5 (sd 0·5) months of age) were divided by sex into five groups. Treatment diets contained algae biomass at 4·0, 8·0, 12·0 or 16·0 g/kg replacing poultry fat (n-6 source). Cats were fed the respective diet for 62 d and neutered on day 58. Blood samples were collected at the beginning of the experiment (day 1), before neutering (day 58) and 4 d after surgery (day 62) for analysis of inflammation and oxidative markers. Acute-phase protein levels were altered (P < 0·01) in the postoperative period, without any treatment effect (P > 0·05). PGE2 concentrations after surgery were reduced linearly (R2 0·8706; P = 0·002) with microalgal inclusion. Blood platelet count was reduced (P = 0·001) after the surgery regardless treatment, but it was higher in the DHA group compared with control (P < 0·001). The DHA deposition (testicles, R2 0·846; ovaries, R2 0·869) and the n-6:n-3 ratio (testicles, R2 0·859; ovaries, R2 0·955) in gonads had a pattern which fitted a quadratic model. DHA from Schizochytrium spp. modifies PGE2 response after the surgery in cats. The physiological roles of the DHA in the reproduction of cats were not investigated, but its gonadal deposition after supplementation was observed.

Oxylipins are bioactive lipid mediators synthesised from PUFA. The most well-known oxylipins are the eicosanoids derived from arachidonic acid (ARA), and many of them influence cardiac physiology in health and disease. Oxylipins are also formed from other n-3 and n-6 PUFA such as α-linolenic acid (ALA), EPA, DHA and linoleic acid (LA), but fundamental data on the heart oxylipin profile, and the effect of diet and sex on this profile, are lacking. Therefore, weanling female and male Sprague–Dawley rats were given American Institute of Nutrition (AIN)-93G-based diets modified in oil composition to provide higher levels of ALA, EPA, DHA, LA and LA + ALA, compared with control diets. After 6 weeks, free oxylipins in rat hearts were increased primarily by their precursor PUFA, except for EPA oxylipins, which were increased not only by dietary EPA but also by dietary ALA or DHA. Dietary DHA had a greater effect than ALA or EPA on reducing ARA oxylipins. An exception to the dietary n-3 PUFA-lowering effects on ARA oxylipins was observed for several ARA-derived PG metabolites that were higher in rats given EPA diets. Higher dietary LA increased LA oxylipins, but it had no effect on ARA oxylipins. Overall, heart oxylipins were higher in female rats, but this depended on dietary treatment: the female oxylipin:male oxylipin ratio was higher in rats provided the ALA compared with the DHA diet, with other diet groups having ratios in between. In conclusion, individual PUFA and sex have unique and interactive effects on the rat heart free oxylipin profile.

Human subcutaneous dirofilariosis has several clinical presentations. Many cases present as subcutaneous nodules, as a consequence of a local inflammatory reaction that encapsulates and destroys the worms. In addition, there are cases in which migrating worms located in the ocular area remain unencapsulated. In the present work, the levels of two pro-inflammatory eicosanoids, thromboxane B2 (TxB2) and leukotriene B4 (LTB4) are analysed by commercial Enzime-Linked immunosorbent assay (ELISA) in serum samples from 43 individuals, 28 diagnosed as having subcutaneous dirofilariasis presenting a subcutaneous nodule, five diagnosed as having dirofilariasis, in which the worms remained unencapsulated in the periphery of the eye, and ten healthy individuals living in a non-endemic area, used as controls. The worms were surgically removed, identifying Dirofilaria repens as the causative agent in all cases, by Polymerase Chain Reaction (PCR). Individuals with nodules showed significantly higher levels of TxB2 and LTB4 than healthy controls, whereas significant differences in LTB4 levels were observed between individuals with unencapsulated worms and healthy controls. It is speculated that the absence of LTB4 may contribute to the fact that worms remain unencapsulated as a part of immune evasion mechanisms.

Nitric oxide (NO) plays various roles in insect immunity: as a cytotoxic component and as a signalling molecule; and immune-reactive lysozymes (IrLys) provide a first line of humoral immune functions against invading bacteria. Although there is considerable literature on eicosanoid and biogenic monoamine actions on insect immunity, there is no information on the role(s) of these chemicals in inducing NO and IrLys. We addressed this gap by challenging third instar Sarcophaga (Liopygia) argyrostoma (Robineau-Desvoidy) with the Gram-positive bacterium Micrococcus luteus. Here, we report that bacterial challenge induces elevation of NO and IrLys concentrations in haemocytes and in the fat body. The plasma pool content is comparatively low. Eicosanoid biosynthesis inhibitors (EBIs) lead to suppression of both NO and IrLys levels. Control larvae have low constitutive levels of NO and lysozyme concentrations. Octopamine (OA) elicits elevation of NO and IrLys concentrations. A similar effect is obtained by 5-hydroxytryptamine (5-HT) for NO. These data indicate immune-mediating roles of eicosanoids, OA and 5-HT in NO and IrLys activities.

EPA and DHA appear to be the most important n-3 fatty acids, but roles for n-3 docosapentaenoic acid are now also emerging. Intakes of EPA and DHA are usually low, typically below those recommended. Increased intakes result in higher concentrations of EPA and DHA in blood lipids, cells and tissues. Increased content of EPA and DHA modifies the structure of cell membranes and the function of membrane proteins. EPA and DHA modulate the production of lipid mediators and through effects on cell signalling can alter the patterns of gene expression. Through these mechanisms, EPA and DHA alter cell and tissue responsiveness in a way that often results in more optimal conditions for growth, development and maintenance of health. DHA has vital roles in brain and eye development and function. EPA and DHA have a wide range of physiological roles, which are linked to certain health or clinical benefits, particularly related to CVD, cancer, inflammation and neurocognitive function. The benefits of EPA and DHA are evident throughout the life course. Future research will include better identification of the determinants of variation of responses to increased intake of EPA and DHA; more in-depth dose–response studies of the effects of EPA and DHA; clearer identification of the specific roles of EPA, docosapentaenoic acid and DHA; testing strategies to enhance delivery of n-3 fatty acids to the bloodstream; and exploration of sustainable alternatives to fish-derived very long-chain n-3 fatty acids.

This study explores the effect of high dietary arachidonic acid (ARA) levels (high ARA) compared with low dietary ARA levels (control) on the general metabolism using zebrafish as the model organism. The fatty acid composition of today’s ‘modern diet’ tends towards higher n-6 PUFA levels in relation to n-3 PUFA. Low dietary n-3:n-6 PUFA ratio is a health concern, as n-6 PUFA give rise to eicosanoids and PG, which are traditionally considered pro-inflammatory, especially when derived from ARA. Juvenile zebrafish fed a high-ARA diet for 17 d had a lower whole-body n-3:n-6 PUFA ratio compared with zebrafish fed a low-ARA (control) diet (0·6 in the control group v. 0·2 in the high-ARA group). Metabolic profiling revealed altered levels of eicosanoids, PUFA, dicarboxylic acids and complex lipids such as glycerophospholipids and lysophospholipids as the most significant differences compared with the control group. ARA-derived hydroxylated eicosanoids, such as hydroxy-eicosatetraenoic acids, were elevated in response to high-ARA feed. In addition, increased levels of oxidised lipids and amino acids indicated an oxidised environment due to n-6 PUFA excess in the fish. To conclude, our results indicate that an ARA-enriched diet induces changes in complex lipids and immune-related eicosanoids and increases levels of oxidised lipids and amino acids, suggesting oxidative stress and lipid peroxidation.

Low heart rate variability (HRV) predicts sudden cardiac death. Long-chain (LC) n-3 PUFA (C20–C22) status is positively associated with HRV. This cross-sectional study investigated whether vegans aged 40–70 years (n 23), whose diets are naturally free from EPA (20 : 5n-3) and DHA (22 : 6n-3), have lower HRV compared with omnivores (n 24). Proportions of LC n-3 PUFA in erythrocyte membranes, plasma fatty acids and concentrations of plasma LC n-3 PUFA-derived lipid mediators were significantly lower in vegans. Day-time interbeat intervals (IBI), adjusted for physical activity, age, BMI and sex, were significantly shorter in vegans compared with omnivores (mean difference −67 ms; 95 % CI −130, −3·4, P<0·05), but there were no significant differences over 24 h or during sleep. Vegans had higher overall HRV, measured as 24 h standard deviation of normal-to-normal intervals (SDNN) (mean adjusted difference 27 ms; 95 % CI 1, 52, P=0·039). Conversely, vegans presented with decreased 8 h day-time HRV: mean adjusted difference in SDNN −20 ms; 95 % CI −37, −3, P=0·021, with no differences during nocturnal sleep. Day-time parameters of beat-to-beat HRV (root of the mean of the sum of the squares of differences between adjacent normal-to-normal intervals, percentage of adjacent normal-to-normal intervals that differ by >50 % and high-frequency power) were similarly lower in vegans, with no differences during sleep. In conclusion, vegans have higher 24 h SDNN, but lower day-time HRV and shorter day-time IBI relative to comparable omnivores. Vegans may have reduced availability of precursor markers for pro-resolving lipid mediators; it remains to be determined whether there is a direct link with impaired cardiac function in populations with low-n-3 status.

We have previously shown nutritional intervention with fish oil (n-3 PUFA) to reduce numerous complications associated with the metabolic syndrome (MetS) in the JCR:LA-corpulent (cp) rat. In the present study, we sought to explore the potential role of fish oil to prevent glomerulosclerosis in JCR:LA-cp rats via renal eicosanoid metabolism and lipidomic analysis. Male lean and MetS JCR:LA-cp rats were fed a lipid-balanced diet supplemented with fish oil (5 or 10 % of total fat). After 16 weeks of feeding, albuminuria was significantly reduced in MetS rats supplemented with 5 or 10 % fish oil ( − 53 and − 70 %, respectively, compared with the untreated MetS rats). The 5 % fish oil diet resulted in markedly lower glomerulosclerosis ( − 43 %) in MetS rats and to a lesser extent in those supplemented with 10 % fish oil. Interestingly, untreated MetS rats had higher levels of 11- and 12-hydroxyeicosatetraenoic acids (HETE) v. lean rats. Dietary fish oil reduced these levels, as well as other (5-, 9- and 15-) HETE. Whilst genotype did not alter prostanoid levels, fish oil reduced endogenous renal levels of 6-keto PGF1α (PGI2 metabolite), thromboxane B2 (TxB2), PGF2α and PGD2 by approximately 60 % in rats fed 10 % fish oil, and TxB2 ( − 50 %) and PGF2α ( − 41 %) in rats fed 5 % fish oil. In conclusion, dietary fish oil prevented glomerular damage in MetS rats and mitigated the elevation in renal HETE levels. These results suggest a potential role for dietary fish oil to improve dysfunctional renal eicosanoid metabolism associated with kidney damage during conditions of the MetS.

Inflammation is part of the normal host response to infection and injury. Eicosanoids, cytokines, chemokines, adhesion molecules and other inflammatory molecules are frequently produced during this process. Numerous studies in humans have documented the inflammation-limiting properties of omega-3 fatty acids, but only a few have been randomised clinical trials. The aim of this study was to perform a systematic search of randomised clinical trials on omega-3 fatty acids and inflammatory biomarkers in all subjects including healthy and ill persons up to February 2011 using PubMed and LILACS databases, defined by a specific equation using MeSH terms and limited to randomised clinical trials; there was no any a priori decision to include some diseases and not others. The quality of each publication was validated by using the JADAD scale and the CONSORT checklist. Inflammatory biomarkers were considered as primary outcomes. Twenty-six publications of the last 10 years were selected. Studies included healthy subjects and patients with cardiovascular disease and other chronic and acute diseases; all reported the number of subjects, type of study, type and doses of omega-3 fatty acids, main outcomes and major inflammatory biomarkers. Dietary omega-3 fatty acids are associated with plasma biomarker levels, reflecting lower levels of inflammation and endothelial activation in cardiovascular disease and other chronic and acute diseases, including chronic renal disease, sepsis and acute pancreatitis. However, further research is required before definitive recommendations can be made about the routine use of omega-3 fatty acids in critically ill patients or with neurodegenerative or chronic renal disease.

Egg fat is of considerable importance in the nutrition of the developing chick as a source of energy and essential fatty acids such as linoleic (18:2 n-6) and α-linolenic (18:3 n-3) acids. During incubation, yolk lipids provide fatty acids that are utilized for energy, synthesis of polyunsaturated fatty acids (PUFA)-rich membrane phospholipids, and eicosanoids by the embryo. Eicosanoids derived from n-6 fatty acid are more potent and pro-inflammatory than eicosanoids derived from n-3 fatty acids.

Two models of early life programming as affected by n-3 PUFA are investigated. Egg PUFA enrichment through breeder hen diet (pre-hatch or in ovo) or early post-hatch (within first 5 hours) feeding is investigated. Early access to nutrients (pre- and early post-hatch) is important because in broiler hatchlings that are selected for rapid early growth much of the immune system development occurs early in life. However, the current industry practice of feeding breeding hens diets high in n-6 fatty acids, limits the supply of essential n-3 PUFA in the hatchling. Early access to n-3 PUFA through in ovo or early post-hatch diet led to: (1) increase in the retention of n-3 PUFA in cell membranes, (2) reduction in plasma non-esterified fatty acids, (3) reduced production of pro-inflammatory eicosanoids, (4) suppression of cell-mediated immunity, and (5) alteration in cyclooxygenase-2 protein expression. The effects of an early exposure persisted from 14 to 35 days in different tissues and cells.

Given the fact that broiler birds are raised for 39 to 56 days, and that the effect of pre-hatch and early post-hatch nutrition persists for up to and over 36-47% of post-hatch life, using an early life programming approach will generate new knowledge about the role of maternal and early post-hatch diet in enhancing bird health and welfare.

Antisecretory factor (AF) is expressed in all tissues of mammals, inhibits intestinal hypersecretion and has anti-inflammatory properties as well. Endogenous AF synthesis may be stimulated by feeding hydrothermally processed cereals. Alternatively, freeze-dried egg yolk can be used as a source of exogenous AF. Several reports have suggested that AF from freeze-dried egg yolk may be useful in inflammatory bowel disease. We assessed the effect of freeze-dried, AF-rich egg yolk intake on 2,4,6-trinitrobenzenesulphonic acid (TNBS) colitis. Balb/c mice were randomised to receive (1) AF in sterile drinking-water (4 g/l, n 38) and (2) sterile drinking-water alone (vehicle, n 38) from TNBS or saline administration onwards. Different subsets of mice were killed at weeks 1–3 after TNBS or saline administration. Macroscopic and microscopic damage was assessed in colonic specimens. Eicosanoid and cytokine production was evaluated in supernatants of 24 h-incubated colonic explants. Myeloperoxidase activity was measured in frozen colonic samples, while apoptosis was assessed in paraffined samples by the in situ oligoligation method. AF-treated mice showed a milder colonic damage compared with the vehicle group, which became statistically significant at week 3. This was accompanied by decreased IL-2, IL-1 and leukotriene B4 production at weeks 2 and 3, as well as increased interferon-γ at week 1, in AF-treated mice compared with vehicle-treated mice. AF-treated mice had significantly increased counts of apoptotic cells in the lamina propria at weeks 1 and 2 post-TNBS. In conclusion, the administration of AF-rich egg yolk has a therapeutic effect in the late phases of TNBS colitis in Balb/c mice.

A combined interdisciplinary research strategy is even more crucial in immunology than in many other biological sciences in order to comprehend the closely linked interactions between cell proliferation, molecular signalling and gene rearrangements. Because of the multi-dimensional nature of the immune system, an abundance of different experimental approaches has developed, with a main focus on cellular and molecular mechanisms. The role of metabolism in immunity has been underexplored so far, and yet researchers have made important contributions in describing associations of immune processes and metabolic pathways, such as the central role of the l-arginine pathway in macrophage activation or the immune regulatory functions of the nucleotides. Furthermore, metabolite supplement studies, including nutritional administration and labelled substrates, have opened up new means of manipulating immune mechanisms. Metabolic profiling has introduced a reproducible platform for systemic assessment of changes at the small-molecule level within a host organism, and specific metabolic fingerprints of several parasitic infections have been characterized by 1H NMR spectroscopy. The application of multivariate statistical methods to spectral data has facilitated recovery of biomarkers, such as increased acute phase protein signals, and enabled direct correlation to the relative cytokine levels, which encourages further application of metabolic profiling to explore immune regulatory systems.

The effect of linolenic acid (C18:3ω3) on the development of Strongyloides ratti first-stage larvae (L1) in culture was studied. The fatty acid composition of S. ratti free-living generations was analyzed by gas chromatography. L1 had abundant linoleic acid (C18:2ω6) but its proportion decreased with development. On the contrary, eicosapentaenoic acid (C20:5ω3) and C20:4ω3 were prominent in the filariform larva (L3). Because C20:5ω3 is generally synthesized from C18:3ω3 via C20:4ω3, the high ratio of C20:5ω3/C18:3ω3 of L3 in all the free-living generations suggested that polyunsaturated fatty acid metabolism, particularly the ω-3 series, and eicosanoids produced had important roles in the development of S. ratti L1.

The n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoicacid (DHA) are found in high proportions in oily fish and fish oils. The n-3 PUFA are structurally and functionally distinct from the n-6 PUFA. Typically, human inflammatory cells contain high proportions of the n-6 PUFA arachidonic acid and low proportions of n-3 PUFA. The significance of this difference is that arachidonic acid is the precursor of 2-series prostaglandins and 4-series leukotrienes, which are highly-active mediators of inflammation. Feeding fish oil results in partial replacement of arachidonic acid in inflammatory cell membranes by EPA. This change leads to decreased production of arachidonic acid-derived mediators. This response alone is a potentially beneficial anti-inflammatory effect of n-3 PUFA. However, n-3 PUFA have a number of other effects which might occur downstream of altered eicosanoid production or might be independent of this activity. For example, animal and human studies have shown that dietary fish oil results in suppressed production of pro-inflammatory cytokines and can decrease adhesion molecule expression. These effects occur at the level of altered gene expression. This action might come about through antagonism of the effects of arachidonic acid-derived mediators or through more direct actions on the intracellular signalling pathways which lead to activation of transcription factors such as nuclear factor kappa B (NFêB). Recent studies have shown that n-3 PUFA can down regulate the activity of the nuclear transcription factor NFêB. Fish oil feeding has been shown to ameliorate the symptoms in some animal models of chronic inflammatory disease and to protect against the effects of endotoxin and similar inflammatory challenges. Clinical studies have reported that oral fish oil supplementation has beneficial effects in rheumatoid arthritis and among some patients with asthma, supporting the idea that the n-3 PUFA in fish oil are antiinflammatory. There are indications that inclusion of n-3 PUFA in enteral and parenteral formulas might be beneficial to patients in intensive care or post-surgery.

Over the last 30 years it has become apparent that specific dietary fatty acids are capable of regulating, either directly or indirectly through various signal pathways, the expression of numerous genes, either positively or negatively. Such nutrient-gene interactions have important effects on cell metabolism, differentiation and growth, and ultimately on disease processes. The present review describes some of the more important fatty acid-gene interactions in relation to health and disease in mammalian species, and focuses on the underlying cell signal mechanisms, including various transcription factors, affected by fatty acids and some of their oxygenated derivatives, e.g. the eicosanoids. The review also attempts to clarify some of the complexities of the effects of fatty acids by suggesting a possible overriding regulation by the redox status of the cell. The latter will at least stimulate controversy in this exciting area of lipid research.

Milk enriched in conjugated linoleic acid (CLA) was obtained from cows on pasture supplemented with full-fat rapeseeds (FFR; 2·26g cis 9, trans 11 (c9, t11)-CLA/100g fatty acid methyl esters) and full-fat soyabeans (1·83g c9, t11-CLA/100g fatty acid methyl esters). A control milk fat (1·69g c9, t11-CLA/100g fatty acid methyl esters) was obtained from cows fed on pasture only. The present study assessed the potency of the CLA-enriched milk fats to modulate biomarkers that had previously been observed to respond to c9, t11-CLA in the MCF-7 and SW480 cell lines. Cell numbers decreased (P<0·05) by up to 61 and 58% following the incubation of MCF-7 and SW480 cells, respectively, for 4d with milk fats (yielding CLA concentrations between 60·2 and 80·6μM). The FFR milk fat, containing the highest CLA content, increased (P<0·05) [14C]arachidonic acid (AA) uptake into the monoacylglycerol fraction of MCF-7 and SW480 cells while it decreased (P<0·05) uptake into the phospholipid fraction of the latter. This milk fat also decreased (P<0·05) [14C]AA conversion to prostaglandin (PG) E2 while increasing conversion to PGF2α in both cell lines. All milk-fat samples increased (P<0·05) lipid peroxidation as measured by 8-epi-PGF2α in both cell lines. In SW480 cells the milk-fat samples decreased (P<0·05) bcl-2 and cytosolic glutathione levels while increasing (P<0·05) membrane-associated annexin V levels. All milk-fat samples decreased (P<0·05) the expression of ras in SW480 cells. These data suggest that milk-fat CLA was effective at modulating synthetic CLA-responsive biomarkers.

Ischaemia reperfusion injury is a common and important phenomenon that occurs predictably in patients undergoing such procedures as cardiopulmonary bypass, thrombolysis, surgery under tourniquet, organ transplantation or embolectomy. Oxidative stress and the resulting lipid peroxidation play a major role in reperfusion injury. Membrane and cellular dysfunction result and, subsequently, organ injury or failure may ensue. Traditional methods of quantifying ischaemia reperfusion injury, including measurement of malondialdehyde, lack specificity and sensitivity. It was reported in 1990 that isoprostanes, a series of prostaglandin-like compounds, are produced by the free radical-catalyzed peroxidation of arachidonic acid. Measurement of the isoprostane concentration in urine or plasma provides the most reliable, non-invasive method currently available to assess oxidative stress in vivo. Serial measurement of isoprostanes in biological fluids has enhanced our understanding of the mechanisms underlying ischaemia reperfusion injury itself and its role in certain diseases. Furthermore, measurement of the isoprostane concentration provides a means to assess the effects of prophylactic and therapeutic interventions. In the future, the development of rapid, simple assays for isoprostanes offers the potential to assess prognosis during and after ischaemia reperfusion events.

To explore whether the metabolic responses to trans, compared with cis, fatty acids depend on the source of dietary polyunsaturated fatty acids (PUFA), male Sprague-Dawley rats, 5 weeks old, were fed on diets containing 30 g oleic (cis) or elaidic (trans) acids/kg in combination with either 70 g perilla oil (α-linolenic acid) or safflowerseed oil (linoleic acid)/kg for 3 weeks in separate experiments. The dietary fats were adjusted to have the same level of total PUFA. The dietary manipulation did not influence the growth indices, but spleen weight was greater when the dietary PUFA source was perilla oil. The incorporation of trans fatty acid into liver phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine and adipose tissue lipids, particularly phospholipids, was significantly higher when rats were fed on safflowerseed oil compared with perilla oil. However, only limited differences were observed in the effects of cis and trans fatty acids on the proportions of PUFA in liver phospholipids. Splenic production of prostaglandin E2 was reduced by trans fatty acid when safflowerseed oil was the PUFA source, but no trans effect was observed on leukotriene C4 production. Dietary PUFA significantly influenced the concentration of plasma immunoglobulins (Ig) but the effect of geometry was only seen in IgG which was increased by trans acid. Dietary trans fatty acid increased the CD4+: CD8+ T-lymphocyte ratio in the spleen, reflecting a decreasing trend of the proportion of CD8+, when combined with perilla oil. These observations indicate that the type of PUFA simultaneously ingested specifically infiuences the effect that trans acid exerts on PUFA metabolism, eicosanoid production and some immune indices.

The effect of short- and long-term feeding with L-carnitine, L-acetyl carnitine and L-propionyl carnitine on the production of eicosanoids front in vitro stimulated carrageenan-induced rat peritoneal macrophages was investigated. Both young (4 weeks) and old (18 months) rats were used. A lower number of cells was isolated from the peritonea of treated than control young rats after 4 d feeding, but after 60 d no differences were observed. A similar reduction in cell number was found when old animals were given L-acetyl carnitine or L-propionyl carnitine (acutely) or L-acetyl carnitine or L-carnitine (chronically). Plasma carnitine levels were higher in young rats given carnitine both chronically and acutely. Carnitine derivatives were without effect. In contrast, levels of total carnitine in the plasma of old rats given L-carnitine and L-acetyl carnitine for 4 d and 60 d were higher than in controls. There was no correlation between total plasma carnitine level and effects on prostaglandin, thromboxane and leukotriene B4 (LTB4) production. In young rats the most important changes were observed in relation to the production of prostacyclin (PGI2), measured as 6 keto-prostaglandin Flα. Prostacyclin production was higher in the groups given carnitine or its derivatives. The net result of the changes in PGI2 was that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin Flα:LTB4 ratios tended to be higher in cells from young animals following short-term feeding with L-carnitine. When young rats were given carnitine compounds for 60 d PGI2 production was lower in cells from L-acetyl carnitine- and L-propionyl carnitine-fed animals. The net result of the changes in PGI2 was that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin F1α:LTB4 ratios were lower in cells from animals fed with carnitine compounds. In old rats the PGI2 production was lower after short-term feeding with carnitine compounds and was higher after long-term feeding. LTB4 production was lower after L-carnitine and L-acetyl carnitine treatment for 4 d and also lower after 60 d treatment with L-acetyl carnitine. The net results of the changes in PGI2 were that the 6 keto-prostaglandin F1α: thromboxane B2 and the 6 keto-prostaglandin F1α:LTB4 ratios were lower after short-term feeding of all three compounds and higher after the long-term treatment with L-acetyl carnitine and L-propionyl carnitine in old rats. By long-term treatment with low-dose aspirin of patients with heart failure and claudication, the 6 keto-prostaglandin F1α: thromboxane B2 ratio is positively increased, which is a beneficial cardioprotective effect. The mechanism of action of carnitine in heart failure and claudication could also be achieved by an increase of this ratio. Our results suggest that elderly patients could be treated chronically by carnitine to obtain this beneficial effect.