Altered monocyte CD44 expression in peripheral arterial disease is corrected by fish oil supplementation.

BACKGROUND AND AIMS: CD44 and its splice variants can be expressed on all leukocytes, conferring adhesive properties and enhancing cellular recruitment to the endothelium during inflammation. CD44 expression is increased in inflammatory conditions such as rheumatoid arthritis and CD44 variant 3 (CD44v3) expression may be associated with inflammation. We have examined CD44 and CD44v3 expression on peripheral blood monocytes from patients with peripheral arterial disease (PAD) and healthy controls. We have also examined the effect of fish oil supplementation on these markers. METHODS AND RESULTS: CD44 and CD44v3 were assessed at baseline and following dietary supplementation with fish oil for 12 weeks in both PAD and control groups. Monocytes from PAD patients had higher CD44 expression than those from controls (median intensity fluorescence (MIF): 480+/-278 vs 336+/-251 (mean+/-SD); p<0.001). Following 12 weeks' dietary supplementation with fish oil, CD44 expression was reduced in PAD patients (MIF: 480+/-278 vs 427+/-262; p=0.05) but not in controls (336+/-251 vs 355+/-280; ns). Monocyte CD44v3 expression was lower in cultured monocytes from PAD patients compared to those from controls (0.15+/-0.15 vs 0.22+/-0.14 OD units; p<0.02). This was increased in the PAD group following fish oil supplementation (0.15+/-0.14 to 0.27+/-0.23 OD units; p<0.001). CONCLUSION: Monocyte CD44 and CD44v3 expression are altered in arterial disease but are returned towards levels seen in control subjects by dietary fish oil supplementation.

Nutrition in clinical practice-the refeeding syndrome: illustrative cases and guidelines for prevention and treatment.

The refeeding syndrome is a potentially lethal complication of refeeding in patients who are severely malnourished from whatever cause. Too rapid refeeding, particularly with carbohydrate may precipitate a number of metabolic and pathophysiological complications, which may adversely affect the cardiac, respiratory, haematological, hepatic and neuromuscular systems leading to clinical complications and even death. We aimed to review the development of the refeeding syndrome in a variety of situations and, from this and the literature, devise guidelines to prevent and treat the condition. We report seven cases illustrating different aspects of the refeeding syndrome and the measures used to treat it. The specific complications encountered, their physiological mechanisms, identification of patients at risk, and prevention and treatment are discussed. Each case developed one or more of the features of the refeeding syndrome including deficiencies and low plasma levels of potassium, phosphate, magnesium and thiamine combined with salt and water retention. These responded to specific interventions. In most cases, these abnormalities could have been anticipated and prevented. The main features of the refeeding syndrome are described with a protocol to anticipate, prevent and treat the condition in adults.

Polymorphisms in cytokine genes influence long-term survival differently in elderly male and female patients.

OBJECTIVES: We asked if single nucleotide polymorphisms (SNP) in inflammatory cytokine genes related to 3-year survival in ill elderly subjects and if genotypes differed between the elderly and a younger control population. DESIGN: Prospective observational study. SETTING: Two geriatric departments at a university hospital. SUBJECTS: Eighty three acutely admitted geriatric patients (83 +/- 7 year, 70% women) and 207 young healthy subjects (40 +/- 1 year, 37% women) were included. OUTCOME MEASURES: Single nucleotide polymorphisms in the genes of tumour necrosis factor (TNF)-alpha-308 G/A, interleukin (IL)-1beta-511 C/T, IL-6-174 G/C and IL-10-1082 A/G were analysed. In the geriatric patients SNP in lymphotoxin (LT)-alpha +252 G/A and serum levels of TNF-alpha, IL-6, IL-10, soluble IL-I receptor(R)II were also determined, as well as the 3-year mortality. RESULTS: The allele distribution did not differ significantly between the elderly and the young. In the female elderly, 3-year survival was doubled (P < 0.05) in those with the high-producing genotypes of IL-6 -174 GG and TNF-alpha -308 GA compared with those with low-producing alleles. In contrast, men with high-producing LT-alpha +252 AA and IL-1beta-511 CT&TT genotypes displayed halved 3-year survival (P < 0.05) compared with those with low-producing genotypes, whereas possession of the high-producing IL-10 -1082 GG genotype favoured survival. Serum IL-10 was higher in the high-producing IL-10 genotype in females. CONCLUSION: As high-producing IL-6 -174 genotype favoured 3-year survival in women, whereas the likewise high-producing LT-alpha +252 and IL-1beta -511 genotypes were associated with poor survival in men, we conclude that the specific genotypes, in association with gender, may act as determinants for survival in elderly patients.

Comparison of the pro-inflammatory potential of monocytes from healthy adults and those with peripheral arterial disease using an in vitro culture model.

We adapted a monocyte:endothelial cell co-culture model to investigate the pro-inflammatory potential of monocytes from patients with peripheral arterial disease (PAD). Isolated monocytes were cultured with human umbilical vein endothelial cells (HUVEC) for 24h, after which the ability of the HUVEC to recruit flowing neutrophils was tested. Development of a usable protocol required comparisons of primary HUVEC with cells that had been passaged and/or frozen and thawed, evaluation of optimal culture media and comparison of monocytes from freshly drawn and stored blood. We found, for instance, that expansion of HUVEC was assisted by inclusion of hydrocortisone, but this agent was withdrawn before the test phase because it reduced responses of HUVEC. Using the optimal practical protocol, we found great variation in the ability of monocytes from different donors to cause neutrophil adhesion. Slightly more ( approximately 20%) monocytes from patients with PAD adhered to HUVEC than monocytes from healthy controls, and the monocytes from PAD patients induced approximately 70% greater subsequent adhesion of neutrophils. Thus, we developed a functional model of inflammatory potential usable in clinically-related studies and found that patients with PAD had circulating monocytes with greater than normal ability to activate endothelial cells.

Polyunsaturated fatty acids, inflammation and immunity.

Consumption of n-6 polyunsaturated fatty acids greatly exceeds that of n-3 polyunsaturated fatty acids. The n-6 polyunsaturated fatty acid arachidonic gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites) and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids act as arachidonic acid antagonists. Components of both natural and acquired immunity, including the production of key inflammatory cytokines, can be affected by n-3 polyunsaturated fatty acids. Although some of the effects of n-3 fatty acids may be brought about by modulation of the amount and types of eicosanoids made, it is possible that these fatty acids might elicit some of their effects by eicosanoid-independent mechanisms. Such n-3 fatty acid-induced effects may be of use as a therapy for acute and chronic inflammation, and for disorders which involve an inappropriately activated immune response.

C-reactive protein is elevated in symptomatic compared with asymptomatic patients with carotid artery disease.

OBJECTIVES: to investigate the level of inflammatory markers between symptomatic and asymptomatic carotid stenosis patients. DESIGN: cross-sectional study. MATERIALS AND METHODS: a prospective study of 137 consecutive patients, admitted electively for carotid endarterectomy during 1997-2000, was conducted. 125 patients had cerebrovascular symptoms: either stroke (neurological deficit >24 h), Transient ischaemic attack (neurological deficit<24 h) or amaurosis fugax. Twelve patients were asymptomatic. A medical history and a fasting venous blood sample were taken from each patient around 6 weeks before surgery. The plasma concentrations of cholesterol and of inflammatory markers; (high sensitivity C-reactive protein (hs-CRP), sICAM-1, sVCAM-1, sE-selectin) were determined. RESULTS: the concentration of hs-CRP in the symptomatic group (3.9 mg/L) was significantly higher than in the asymptomatic group (2.1 mg/L; p = 0.04). These concentrations were within normal range (<10 mg/L). sICAM-1, sVCAM-1, sE-selectin and total cholesterol concentrations were not different between the two groups. CONCLUSION: plasma hs-CRP was elevated in symptomatic compared to asymptomatic patients with carotid artery disease. High sensitivity C-reactive protein has been shown to be of prognostic value in a number of cardiovascular conditions and this study suggests it may be of value to identify patient at high risk of developing neurological deficits.

Nutritional modulation of immune function.

The inflammatory response to injury and infection, although an essential part of immune function, carries the risk of severe tissue depletion and immunosuppression. These outcomes increase morbidity and delay recovery. Evidence is accumulating that single-nucleotide polymorphisms in the genes controlling pro-inflammatory cytokine production adversely influence the response. Immunonutrition provides a means of modulating the inflammatory response to injury and infection, and thereby improves clinical outcome. n-3 Polyunsaturated fatty acids (n-3 PUFA), glutamine, arginine, S amino acids and nucleotides are important components of immunonutrient mixes. While animal model studies suggest that all these components may exert a beneficial effect in patients, the number of large randomized placebo-controlled trials utilizing immunonutrition is fairly limited and the observed effects are relatively small. Meta-analyses suggest that while immunonutrition may not reduce mortality rates, a reduction in hospital length of stay, decreased requirements for ventilation and lower infection rates are achieved by this mode of nutrition. The present paper discusses some underlying reasons for the difficulty in demonstrating the clinical efficacy of immunonutrition. Paramount among these reasons is the antioxidant status and genetic background of the patient. A number of studies suggest that there is an inverse relationship between inflammation and T-cell function. Immuno-enhancive effects have been shown in a number of studies in which n-3 PUFA, glutamine and N-acetyl cysteine have been employed. All these nutrients may exert their effects by suppressing inflammation; n-3 PUFA by direct suppression of the process and glutamine and N-acetyl cysteine by acting indirectly on antioxidant status. Glutamine and nucleotides exert a direct effect on lymphocyte proliferation. Preliminary data suggests that not all genotypes are equally sensitive to the effects of immunonutrition. When further studies have been conducted to discern the precise interaction between each individual's genotype of relevance to the response to injury and infection, and immunonutrients, the level of precision in the application of immunonutrition will undoubtedly improve.

Immunonutrition: role of sulfur amino acids, related amino acids, and polyamines.

Pro-inflammatory cytokines mediate widespread changes in protein metabolism. Amino acids released from peripheral tissues fulfill a number of functions. They act as substrate for acute phase protein and immunoglobulin synthesis and, together with polyamines, in the replication of immune cells. Demands for specific amino acids may outstrip the supply from endogenous sources. A number of strands of evidence suggest that sulphur amino acids, and amino acids that are metabolically related to them, may be required in increased amounts. Protein deficiency impairs the acute phase response. However, sulfur amino acid insufficiency compromises glutathione synthesis, to a greater extent than hepatic protein synthesis, in the presence and absence of an inflammatory stimulus. The resulting effect may be compromised antioxidant defences. Functioning of T cells is dependent on intracellular glutathione concentrations and may also be affected by sulphur amino acid insufficiency. It has been suggested that the increased N excretion, which occurs during the immune response, is a reflection of a relative imbalance in the profile of amino acids released from peripheral tissues and the requirements imposed by the synthesis of substances involved in the acute phase response. Phenylalanine, tyrosine, tryptophan serine, and cysteine are released in amounts closest to requirements. Polyamine synthesis may be important for the fidelity of the enhanced level DNA transcription and RNA translation that occurs in response to infection and during tissue repair, gut growth after surgery, and in gut barrier functions. Although synthesized de novo from ornithine, arginine and S-adenosyl methionine (SAM), substantial recycling is a key feature of polyamine metabolism. The recycling may be a reflection of the need to maintain adequate tissue SAM during periods of rapid cell growth. During an immune/inflammatory response the combination of enhanced utilization of cysteine for glutathione synthesis and cell replication may lead to depletion of cellular SAM. A relatively small addition of polyamines to the diet may improve gut-associated aspects of the hosts' antibacterial defenses.

Nutritional modulation of cytokine biology.

The pro-inflammatory cytokines and oxidant molecules produced during the inflammatory response, which follows infection and injury, may be beneficial, or detrimental to the patient, depending on the amounts and contexts in which they are produced. Aberrant or excessive production has been implicated in inflammatory disease, and sepsis. The upregulation of cytokine production by NF kappa B and NFIL-6 activation by oxidants increases the likelihood of cytokine-induced mortality and morbidity. Complex systems exist for the control of cytokine production and oxidant actions. The former include the hormones of the hypothalamo-pituitary-adrenal axis, acute phase proteins, and endogenous inhibitors of interleukin (IL)-1 and tumor necrosis factor (TNF). The latter include endogenously synthesized antioxidants, such as glutathione and dietary antioxidants, such as tocopherols, ascorbates and cachectins. Nutrients change cytokine production and potency by influencing tissue concentrations of many of the molecules involved in cytokine biology. Monounsaturated fatty acids and omega-3 polyunsaturated fatty acids (PUFAs) suppress TNF and IL-1 production and actions, while n-6 PUFAs exert the opposite effect. Changes in eicosanoid production are more likely to underlie this effect than alterations in membrane fluidity. Low antioxidant intake results in enhanced cytokine production and effects. The anorexia that follows infection and injury, may be purposeful to permit release of substrate from endogenous sources to support and control the inflammatory process. Therefore, prior as well as concurrent nutrient intake are of importance in determining the outcome of the inflammatory response.

Modulation of pro-inflammatory cytokine biology by unsaturated fatty acids.

The production of pro-inflammatory cytokines, such as interleukins 1 and 6 and tumour necrosis factors, occurs rapidly following trauma or invasion of the body by pathogenic organisms. The cytokines mediate the wide range of symptoms associated with trauma and infection, such as fever, anorexia, tissue wasting, acute phase protein production and immunomodulation. In part, the symptoms result from a co-ordinated response, in which the immune system is activated and nutrients released, from endogenous sources, to provide substrate for the immune system. Although the cytokine mediated response is an essential part of the response to trauma and infection, excessive production of pro-inflammatory cytokines, or production of cytokines in the wrong biological context, are associated with mortality and pathology in a wide range of diseases, such as malaria, sepsis, rheumatoid arthritis, inflammatory bowel disease, cancer and AIDS. Cytokine biology can be modulated by antiinflammatory drugs, recombinant cytokine receptor antagonists and nutrients. Among the nutrients, fats have a large potential for modulating cytokine biology. A number of trials have demonstrated the anti-inflammatory effects of fish oils, which are rich in n-3 polyunsaturated fatty acids, in rheumatoid arthritis, inflammatory bowel disease, psoriasis and asthma. Animal studies, conducted by ourselves and others, indicate that a range of fats can modulate pro-inflammatory cytokine production and actions. In summary fats rich in n-6 polyunsaturated fatty acids enhance IL1 production and tissue responsiveness to cytokines, fats rich in n-3 polyunsaturated fatty acids have the opposite effect, monounsaturated fatty acids decrease tissue responsiveness to cytokines and IL6 production is enhanced by total unsaturated fatty acid intake. There are a large number of potential cellular mechanisms which may mediate the effects observed. The majority relate to the ability of fats to alter the composition of membrane phospholipids. As a consequence of alterations in phospholipid composition, membrane fluidity may change, altering binding of cytokines to receptors and G protein activity. The nature of substrate for various signalling pathways associated with cytokine production and actions may also be changed. Consequently, alterations in eicosanoid production and activation of protein kinase C may occur. We have examined a number of these potential mechanisms in peritoneal macrophages of rats fed fats with a wide range of fatty acid composition. We have found that the total C18:2 and 20:4 diacyl species of phosphatidylethanolamine in peritoneal macrophages relates in a positive curvilinear fashion with dietary linoleic acid intake; that TNF induced IL1 and IL6 production relate in a positive curvilinear fashion to linoleic acid intake; that leukotriene B4 production relates positively with dietary linoleic acid intake over a range of moderate intakes and is suppressed at high intakes, while PGE2 production is enhanced. There was no clear relationship between linoleic acid intake and membrane fluidity, however fluidity was influenced in a complex manner by the type of fat in the diet, the period over which the fat was fed and the presence of absence of TNF stimulation. None of the proposed mechanisms, acting alone, can explain the positive effect of dietary linoleic acid intake on pro-inflammatory cytokine production. However each may be involved, in part, in the modulatory effects observed.

Fasting in healthy individuals and adaption to undernutrition during chronic disease.

During long-term fasting, gluconeogenesis from amino acids was thought to lessen, when ketone bodies from lipolysis became a major fuel source. Thus, muscle mass is conserved. However, recent studies show that this adaptation does not occur in chronic undernourishment. In cancer, chronic undernutrition without disease, and HIV infection, carbohydrate utilization is high. Enhanced hepatic glucose production occurs in active inflammatory bowel disease and in underweight cancer patients. Repletion of tissue after undernutrition is energetically inefficient because of enhanced diet induced thermogenesis (following anorexia nervosa) and decreased fat, and increased protein, oxidation (in tuberculosis).

Dietary sulphur amino acid adequacy influences glutathione synthesis and glutathione-dependent enzymes during the inflammatory response to endotoxin and tumour necrosis factor-alpha in rats.

1. Glutathione concentrations in liver and lung fall when food intake or sulphur amino acid intake is inadequate. However, concentrations may be restored during inflammation, despite anorexia, provided that prior sulphur amino acid intake is adequate. 2. We studied the mechanisms of these changes by measuring the effect of sulphur amino acid and protein intake on hepatic glutathione synthesis and gamma-glutamylcysteine synthetase activity, hepatic and lung glutathione concentrations, glutathione reductase and glutathione peroxidase activities in young rats given an inflammatory challenge by intraperitoneal injection of tumour necrosis factor-alpha or endotoxin (lipopolysaccharide). 3. Diets containing 200 g of casein and 8 g of L-cysteine/kg (normal-protein diet), or 80 g of casein and 8 g of L-cysteine, or isonitrogenous amounts of L-methionine or L-alanine (low-protein diets) were fed ad libitum to young Wistar rats for 8 days. Dietary groups were subdivided into three: one subgroup continued feeding ad libitum, a second was given tumour necrosis factor or lipopolysaccharide and killed 24 h thereafter, while the third was pair-fed to the intakes of the second subgroup for 24 h before being killed. 4. Glutathione concentrations in liver and lung were reduced in rats fed the low-protein diet containing alanine, and in all dietary groups when food intake was restricted. The inflammatory challenges restored hepatic glutathione concentrations in all groups but the diet supplemented with alanine, which had an inadequate sulphur amino acid content. In lung, restoration occurred only in animals fed the normal-protein diet. 5. The activity of gamma-glutamylcysteine synthetase, which is rate limiting for glutathione synthesis, was unaffected by dietary or sulphur amino acid intake or by the inflammatory response. Substrate supply may therefore be a major determinant in glutathione synthesis in vivo. 6. Total hepatic glutathione synthesis was affected by food intake, the type and amount of sulphur amino acids in the diet and by inflammation. Total synthesis was 207, 137, 421 and 90 mumol/day for animals fed ad libitum the normal-protein diet, or low-protein diets supplemented with cysteine, methionine or alanine respectively, ad libitum. Pair-feeding resulted in values of 76, 31, 71, and 0 mumol/day respectively. After lipopolysaccharide injection, rates increased to 200, 117, 151 and 56 mumol/day respectively. 8. Reductase and peroxidase activities increased in liver and lung, when low-protein diets which contained supplemental methionine or alanine were consumed ad libitum. A reduction in food intake resulted in enzyme activity changes, which suggested that recycling of glutathione increased in lung and decreased in liver. Injection of tumour necrosis factor reversed this effect. 9. The restoration of glutathione concentrations in liver after an inflammatory challenge is closely associated with an enhanced rate of synthesis and increased recycling. The former is impaired when inadequate sulphur amino acid is consumed before the challenge. In lung, increased recycling of glutathione may help maintain concentrations when food intake is restricted, but not during inflammation.

The influence of dietary lipids on the composition and membrane fluidity of rat hepatocyte plasma membrane.

Weanling male Wistar rats were fed for five weeks on standard rat chow (23 g fat/kg diet) or one of four synthetic diets with butterfat, coconut oil, corn oil, or fish oil as the main lipid source (100 g fat/kg diet). In all diets, 10% of the fat was provided as corn oil to prevent essential fatty acid deficiency. Significant differences were observed in the saturated, monounsaturated, and polyunsaturated fatty acid composition, and in the ratio of cholesterol to phospholipid, in the hepatocyte membranes. The fluidity of hepatocyte plasma membranes was assessed using the fluorescence recovery after photobleaching technique and steady-state fluorescence anisotropy of diphenylhexatriene. No significant differences were found in the fluidity of plasma membranes between animals on the different fat diets, despite diet-induced changes in their fatty acid composition. However, the proportion of lipid free to diffuse in the plasma membrane varied with diet, being significantly greater (P < 0.05) in animals fed chow (63.7%), coconut oil (61.5%), and butterfat (57.6%) diets than in those fed the corn oil (47.3%) diet. Animals fed fish oil showed an intermediate (50.0%) proportion of lipid free to diffuse. The data support the hypothesis that dietary lipids can change both the chemical composition and lateral organization (lipid domain structure) of rat hepatocyte plasma membranes.

The influence of membrane fluidity, TNF receptor binding, cAMP production and GTPase activity on macrophage cytokine production in rats fed a variety of fat diets.

The effects of different dietary fats on peritoneal macrophage plasma membrane fluidity, intracellular cyclic AMP (cAMP) production, GTP hydrolysis and TNF binding and TNF-induced IL1 and IL6 production was investigated. After a four week period, fluidity, as determined by both fluorescence recovery after photobleaching (FRAP) and anisotropy was lowest and highest in animals fed corn and fish oil respectively. After eight weeks feeding, lateral membrane movements were decreased substantially in fish, olive and coconut oil fed dietary groups, whereas an increase in the corn oil fed group was observed, no effect was observed in macrophages from the butter fed group. However, an increase in the packing was observed in macrophages from all dietary groups except in the olive oil fed group. GTPase values for the coconut oil and butter groups were higher than in any other dietary group. After receiving the diet for 8 weeks these differences between the groups were no longer apparent. Exposure of macrophages to TNF had no effect on the rate of GTP hydrolysis. A major enhancement of cAMP production became apparent between weeks 4 and 8 of dietary treatment. After 4 weeks on the diet, values were significantly higher from cells of animals fed corn and olive oils than from animals fed fish oil. After 8 weeks, while there was a general enhancement of production, further differences became apparent. Feeding corn and coconut oils resulted in the highest values and olive oil and chow in the lowest. It is proposed that fats rich in n-3 fatty acids (fish oils) alter membrane fluidity, decrease TNF binding affinity, GTPase activity and cAMP production which appears not to modify cytokine production after short term dietary supplementation. However, after long term feeding it appears that increases in the sensitivity of the TNF receptors plays a major role in modifying cytokine production.

Effect of antioxidative vitamins on immune function with clinical applications.

Infection and trauma cause inflammatory stress in patients. Tissue damage, enhanced inflammatory mediator production and suppressed lymphocyte function may occur as a consequence. The antioxidative vitamins, ascorbic acid and the tocopherols, are important not only for limiting tissue damage but also in preventing increased cytokine production which is a consequence of excessive activation of NF kappa B. Glutathione is a major endogenous antioxidant and is important for lymphocyte replication. Two vitamins, vitamin B6 and riboflavin participate in the maintainance of glutathione status. The former vitamin acts as a cofactor in the synthesis of cysteine (the rate limiting precursor for glutathione biosynthesis) and the latter vitamin is a cofactor for glutathione reductase. Deficiencies in tocopherol, vitamin B6 and riboflavin reduce cell numbers in lymphoid tissues of experimental animals and produce functional abnormalities in the cell mediated immune response. Ascorbic acid and tocopherols exert anti-inflammatory effects in studies in man and animals. In humans, dietary supplementation with ascorbic acid, tocopherols and vitamin B6 enhances a number of aspects of lymphocyte function. The effect is most apparent in the elderly.

The relationship between altered membrane composition, eicosanoids and TNF-induced IL1 and IL6 production in macrophages of rats fed fats of different unsaturated fatty acid composition.

The study investigated the changes in individual molecular species in PE and the effects of a variety of dietary fats with varying proportions of saturated and unsaturated fatty acids on membrane composition, eicosanoid production and cytokine production in thioglycollate-elicited rat macrophages. The data obtained indicates that the greatest degree of modulation by dietary fats on cytokine production was observed after 8 weeks feeding and at this time, the total diacyl species containing linoleic acid (18:2 n-6) and arachidonic acid (20:4 n-6) at the sn-2 position related in a curvilinear fashion to total 18:2 n-6 intake and that IL1 and IL6 production related in a curvilinear fashion to the total diacyl species with 20:4 and 18:2 at the sn-2 position. After 4 weeks of feeding, fish and olive oils enhanced production of IL6 and LTB4, however, while IL1 production, after 8 weeks of dietary treatment, was greatest from macrophages of animals fed corn and olive oils, PGE2 production was greatest in the former group and LTB4 production in the latter. Thus an eicosanoid effect may explain the modulatory influence of olive oil and IL1 production but, cannot explain the effect of corn oil on production of the cytokine. The data from the present study provides some insight into how dietary fats could provide therapy for conditions in which inflammatory cytokines are implicated.