Limited impact of 2 g/day omega-3 fatty acid ethyl esters (Omacor®) on plasma lipids and inflammatory markers in patients awaiting carotid endarterectomy.

The objective of this study was to determine the effects of prescription omega-3 (n-3) fatty acid ethyl esters (Omacor®) on blood pressure, plasma lipids, and inflammatory marker concentrations in patients awaiting carotid endarterectomy. Patients awaiting carotid endarterectomy (n = 121) were randomised to Omacor® or olive oil as placebo (2 g/day) until surgery (median 21 days). Blood pressure, plasma lipids, and plasma inflammatory markers were determined. There were significant decreases in systolic and diastolic blood pressure and in plasma triglyceride, total cholesterol, low density lipoprotein-cholesterol, soluble vascular cellular adhesion molecule 1, and matrix metalloproteinase 2 concentrations, in both groups. The extent of triglyceride lowering was greater with Omacor® (25%) compared with placebo (9%). Soluble E-selectin concentration was significantly decreased in the Omacor® group but increased in the placebo group. At the end of the supplementation period there were no differences in blood pressure or in plasma lipid and inflammatory marker concentrations between the two groups. It is concluded that Omacor® given at 2 g/day for an average of 21 days to patients with advanced carotid atherosclerosis lowers triglycerides and soluble E-selectin concentrations, but has limited broad impact on the plasma lipid profile or on inflammatory markers. This may be because the duration of intervention was too short or the dose of n-3 fatty acids was too low.

Variants in the genes encoding TNF-α, IL-10, and GSTP1 influence the effect of α-tocopherol on inflammatory cell responses in healthy men.

BACKGROUND: Despite evidence of antioxidant effects of vitamin E in vitro and in animal studies, large, randomized clinical trials have not substantiated a benefit of vitamin E in reducing inflammation in humans. An individual's genetic background may affect the response to α-tocopherol supplementation, but this has rarely been investigated. OBJECTIVE: The aim of this study was to explore the role of genetic polymorphisms on changes in LPS-stimulated inflammatory cytokine production from peripheral blood mononuclear cells (PBMCs) after α-tocopherol supplementation. DESIGN: A total of 160 healthy, middle-aged male volunteers (mean age: 52.7 y) were given dietary supplements of either 75 IU (low dose; n = 57) or 600 IU (high dose; n = 103) α-tocopherol/d for 6 wk. The production of TNF-α and IL-1ß, -6, and -10 by PBMCs after LPS stimulation was measured at baseline and after 6 wk. Polymorphisms in 15 genes involved in inflammation or responses to oxidative stress were characterized in the subjects. RESULTS: The ability of α-tocopherol to affect TNF-α production by LPS-stimulated PBMCs was influenced by the TNFA -238 polymorphism (P = 0.016). The ability of α-tocopherol to affect IL-6 production was influenced by the GSTP1 313 polymorphism (P = 0.019). The ability of α-tocopherol to affect IL-1ß production was influenced by the IL10 -592 and -1082 polymorphisms (P = 0.025 and P = 0.016, respectively). CONCLUSIONS: In healthy control subjects, the effect of α-tocopherol supplementation on the production of inflammatory cytokines appears to be dependent on an individual's genotype. These genotype-specific differences may help explain some of the discordant results in studies that used vitamin E.

Docosahexaenoic acid inhibits the adhesion of flowing neutrophils to cytokine stimulated human umbilical vein endothelial cells.

The (n-3) PUFA, DHA, is widely thought to posses the ability to modulate the inflammatory response. However, its modes of interaction with inflammatory cells are poorly understood. In particular, there are limited data on the interactions of DHA with vascular endothelium, the cells that regulate the traffic of leukocytes from the blood into inflamed tissue. Using human umbilical vein endothelial cells (EC) cultured in a flow-based adhesion assay and activated with TNFα, we tested whether supplementing human umbilical vein EC with physiologically achievable concentrations of DHA would inhibit the recruitment of flowing neutrophils. DHA caused a dose-dependent reduction in neutrophil recruitment to the EC surface, although cells that became adherent were activated and could migrate across the human umbilical vein EC monolayer normally. Using EPA as an alternative supplement had no effect on the levels of neutrophil adhesion in this assay. Analysis of adhesion receptor expression by qPCR demonstrated that DHA did not alter the transcriptional activity of human umbilical vein EC. However, DHA did significantly reduce E-selectin expression at the human umbilical vein EC surface without altering the total cellular pool of this adhesion receptor. Thus, we have identified a novel mechanism by which DHA alters the trafficking of leukocytes during inflammation and demonstrate that this involves disruption of intracellular transport mechanisms used to present adhesion molecules on the surface of cytokine-stimulated EC.

Eicosapentaenoic acid (EPA) from highly concentrated n-3 fatty acid ethyl esters is incorporated into advanced atherosclerotic plaques and higher plaque EPA is associated with decreased plaque inflammation and increased stability.

OBJECTIVE: To examine n-3 polyunsaturated fatty acid (PUFA) incorporation into atherosclerotic plaques and the association with plaque inflammation and stability. METHODS AND RESULTS: Patients awaiting carotid endarterectomy (n=121) were randomised to consume control capsules or n-3 PUFA ethyl ester capsules until surgery (median 21 days). The fatty acid compositions of plasma and carotid plaque phospholipids, plaque features, and expression of inflammatory genes were determined. The proportion of eicosapentaenoic acid (EPA) was higher (P<0.0001) in carotid plaque phospholipids in patients in the n-3 PUFA group. Plaques from patients in the n-3 PUFA group had fewer foam cells (P=0.0390). There were no other differences between plaques in the two groups with regard to histological characteristics or morphology. Plaque stability was not different between the two groups. However, the EPA content of plaque phospholipids was inversely associated with plaque instability (P=0.0209), plaque inflammation (P=0.0108), the number of T cells in the plaque (P=0.0097) and a summary score considering a range of plaque features (P=0.0425). Plaques from patients who received n-3 PUFAs had significantly lower levels of mRNA for matrix metalloproteinases (MMP)-7 (P=0.0055), -9 (P=0.0048) and -12 (P=0.0044) and for interleukin-6 (P=0.0395) and intercellular adhesion molecule 1 (P=0.0142). CONCLUSIONS: Atherosclerotic plaques readily incorporate EPA. A higher plaque EPA content is associated with a reduced number of foam cells and T cells, less inflammation and increased stability.

Omega-3 Fatty acids and inflammation: novel interactions reveal a new step in neutrophil recruitment.

Inflammation is a physiological response to tissue trauma or infection, but leukocytes, which are the effector cells of the inflammatory process, have powerful tissue remodelling capabilities. Thus, to ensure their precise localisation, passage of leukocytes from the blood into inflamed tissue is tightly regulated. Recruitment of blood borne neutrophils to the tissue stroma occurs during early inflammation. In this process, peptide agonists of the chemokine family are assumed to provide a chemotactic stimulus capable of supporting the migration of neutrophils across vascular endothelial cells, through the basement membrane of the vessel wall, and out into the tissue stroma. Here, we show that, although an initial chemokine stimulus is essential for the recruitment of flowing neutrophils by endothelial cells stimulated with the inflammatory cytokine tumour necrosis factor-alpha, transit of the endothelial monolayer is regulated by an additional and downstream stimulus. This signal is supplied by the metabolism of the omega-6-polyunsaturated fatty acid (n-6-PUFA), arachidonic acid, into the eicosanoid prostaglandin-D(2) (PGD(2)) by cyclooxygenase (COX) enzymes. This new step in the neutrophil recruitment process was revealed when the dietary n-3-PUFA, eicosapentaenoic acid (EPA), was utilised as an alternative substrate for COX enzymes, leading to the generation of PGD(3). This alternative series eicosanoid inhibited the migration of neutrophils across endothelial cells by antagonising the PGD(2) receptor. Here, we describe a new step in the neutrophil recruitment process that relies upon a lipid-mediated signal to regulate the migration of neutrophils across endothelial cells. PGD(2) signalling is subordinate to the chemokine-mediated activation of neutrophils, but without the sequential delivery of this signal, neutrophils fail to penetrate the endothelial cell monolayer. Importantly, the ability of the dietary n-3-PUFA, EPA, to inhibit this process not only revealed an unsuspected level of regulation in the migration of inflammatory leukocytes, it also contributes to our understanding of the interactions of this bioactive lipid with the inflammatory system. Moreover, it indicates the potential for novel therapeutics that target the inflammatory system with greater affinity and/or specificity than supplementing the diet with n-3-PUFAs.

Polymorphisms in the CD36 gene modulate the ability of fish oil supplements to lower fasting plasma triacyl glycerol and raise HDL cholesterol concentrations in healthy middle-aged men.

Five SNPs in the CD36 gene, 25444G>A, 27645del>ins, 30294G>C, -31118G>A and -33137A>G in haplotypic combinations, link to fasting plasma NEFA concentrations. Fish oil lowers TAG concentrations. The influence of CD36 SNPs on hypotriglyceridemic effects is unknown. The study examines how four of the SNPs modify the effects of fish oil on fasting plasma TAG, NEFA, glucose LDL and HDL cholesterol concentrations in 111 healthy, middle-aged, Caucasian men. Subjects consumed habitual diets while taking 6g MaxEPA daily for 12 weeks. TAG decreased from 1.48 mol/l to 0.11 mmol/l, and glucose and HDL rose from 5.92 to 0.15 mmol/l and from 1.27 to 0.04 mmol/l, respectively, irrespective of genotype. NEFA was unaffected. Significant falls in TAG only occurred in individuals with the GG variant of the 25444, 30294, -31118 or -33137 SNPs. The TAG-lowering effects may be via stimulation of CD36 activity in extrahepatic tissue in individuals with the GG variants of these SNPs.

Dietary supplementation with fish oil modifies the ability of human monocytes to induce an inflammatory response.

Monocytes/macrophages are key orchestrators of inflammation and are involved in the pathogenesis of chronic inflammatory disorders, including atherosclerosis. (n-3) Fatty acids, found in fish oil, have been shown to have protective effects in such disorders. To investigate possible modes of action, we used a monocyte:endothelial cell (EC) coculture model to investigate the pro-inflammatory potential of monocytes. Monocytes were isolated from the blood of donors with peripheral arterial disease (PAD) or control donors, before and after a 12-wk supplementation of their diet with fish oil. The monocytes were cultured with human umbilical vein EC (HUVEC) for 24 h, after which the ability of the HUVEC to recruit flowing neutrophils was tested. Monocytes from either group of donors stimulated the EC to support the adhesion and migration of neutrophils. Fish oil supplementation reduced the potency of monocytes from normal subjects, but not those from patients with PAD, to induce recruitment. Concurrent medication may have acted as a complicating factor. On subgroup analysis, only those free of medication showed a significant effect of fish oil. Responses before or after supplementation were not closely linked to patterns of secretion of cytokines by cultured monocytes, tested in parallel monocultures. These results suggest that fish oil can modulate the ability of monocytes to stimulate EC and that this might contribute to their protective effects against chronic inflammatory disorders. Benefits, however, may depend on existing medical status and on other treatments being received.

Fish oil induced increase in walking distance, but not ankle brachial pressure index, in peripheral arterial disease is dependent on both body mass index and inflammatory genotype.

Peripheral arterial disease (PAD) is an atherosclerotic disease. Evidence suggests that atherosclerosis is an inflammatory condition and long chain n-3 fatty acids, found in oily fish and fish oils, have been shown to reduce inflammation. Genetic and lifestyle factors such as body mass index (BMI) also influence inflammation. In this study we have examined the effect of fish oil in patients with claudication secondary to PAD. Fish oil supplementation, providing 1g EPA and 0.7 g DHA per day for 12 weeks, increased walking distance on a treadmill set at 3.2 km/h with a 7% incline. Walking distance to first pain increased from 76.2+/-8.5 m before fish oil to 140.6+/-25.5 m after fish oil (mean+/-SEM, p=0.004) and total distance walked increased from 160.0+/-21.5 m before fish oil to 242.1+/-34.5 m after fish oil (p=0.002). Fish oil supplementation also improved ankle brachial pressure index (ABPI) from 0.599+/-0.017 before fish oil to 0.776+/-0.030 after fish oil (p<0.001). The increase in walking distance was dependent on both BMI and genotype for single nucleotide polymorphisms in the genes encoding the pro-inflammatory cytokines tumour necrosis factor-alpha and interleukin (IL)-1beta and the anti-inflammatory cytokine IL-10 (detected using amplification refractory mutation system polymerase chain reaction). Neither BMI nor any of the genotypes examined affected the ability of fish oil to increase ABPI. The mechanisms by which fish oil affects walking distance and ABPI do not appear to be the same.

The effects of sulfur amino acid intake on immune function in humans.

No direct data exist on the influence of supranormal intakes of sulfur amino acids on immune function in humans. However 3 major products of sulfur amino acids, glutathione (GSH), homocysteine (Hcy), and taurine (Tau), influence, mainly, inflammatory aspects of the immune response in vitro and in vivo. Methionine intakes above approximately 1 g/d transiently raise plasma Tau, Hcy, and GSH. Tau and GSH ameliorate inflammation. Hcy has the opposite effect. A biphasic relation, between cellular GSH and CD4+ and CD8+ numbers occurs in healthy men. How changes in sulfur amino acid intake influence this phenomenon is unknown. In animals, high Tau intakes are antiinflammatory. How immune function in humans is affected is unknown. A positive relation between plasma neopterin (a marker of a Th-1-type immune response) and Hcy indicates that Hcy may play a part in inflammatory aspects of Parkinson's disease and aging. In vitro, Hcy, at concentrations seen following consumption of approximately 6 g L-methionine/d in adults, increases the interactions among T lymphocytes, monocytes, and endothelium. Whether a similar phenomenon occurs in vivo is unknown. Polymorphisms in the methylenetetrahydrofolate reductase gene are associated with raised plasma Hcy in young but not old subjects. The relation of this observation to immune function is unknown. The relationships among Hcy, inflammatory aspects of disease, and in vitro alterations in immune cell behavior create a cautionary note about supplementation of diets with l-methionine to raise intake above approximately 1 g/d. Studies directly linking methionine intake, genetics, plasma Hcy, Tau, and GSH and immune function are needed.

Does nutrition have a role in peripheral vascular disease?

Peripheral vascular disease (PVD) is a manifestation of systemic atherosclerosis in the lower limbs, and PVD patients have a 3- to 5-fold increased risk of cardiovascular mortality compared with age-matched controls. Nevertheless, recent reports show how PVD patients are undertreated with regard to CVD risk-factor reduction and the use of lipid-lowering or antiplatelet drugs. There is appreciable evidence that demonstrates the beneficial effects of certain nutrients and dietary habits in the prevention of CVD, but there has been little attention paid to the role of nutrients in PVD. The purpose of the present review is to provide an overview of our understanding of how foods could possibly benefit PVD. In the last few decades, several nutrients have arisen as potentially health-promoting in PVD. While nutritional interventions in PVD show positive clinical effects for fish oil, carnitine or vitamin E, others such as olive oil or vitamin C seem to interact only at a biochemical level by decreasing risk factors. Moreover, only epidemiological associations exist for the potential role of fibre, folates or vitamin B6 in this disease. In all cases, the limited data available provide no clear-cut evidence in favour of the clinical benefit of nutritional interventions aimed at reducing risk factors and ameliorating symptoms in PVD patients. No practical recommendations can be given at this stage, and further studies are clearly needed.

Incorporation of cis-9, trans-11 conjugated linoleic acid and vaccenic acid (trans-11 18 : 1) into plasma and leucocyte lipids in healthy men consuming dairy products naturally enriched in these fatty acids.

The present study investigated whether consuming dairy products naturally enriched in cis-9, trans-11 (c9,t11) conjugated linoleic acid (CLA) by modification of cattle feed increases the concentration of this isomer in plasma and cellular lipids in healthy men. The study had a double-blind cross-over design. Subjects aged 34-60 years consumed dairy products available from food retailers for 1 week and then either control (0.17 g c9,t11 CLA/d; 0.31 g trans-vaccenic acid (tVA)/d) or CLA-enriched (1.43 g c9,t11 CLA/d; 4.71 g tVA/d) dairy products for 6 weeks. After 7 weeks washout, this was repeated with the alternate products. c9,t11 CLA concentration in plasma lipids was lower after consuming the control products, which may reflect the two-fold greater c9,t11 CLA content of the commercial products. Consuming the CLA-enriched dairy products increased the c9,t11 CLA concentration in plasma phosphatidylcholine (PC) (38 %; P = 0.035), triacylglycerol (TAG) (22 %; P < 0.0001) and cholesteryl esters (205 %; P < 0.0001), and in peripheral blood mononuclear cells (PBMC) (238 %; P < 0.0001), while tVA concentration was greater in plasma PC (65 %; P = 0.035), TAG (98 %; P = 0.001) and PBMC (84 %; P = 0.004). Overall, the present study shows that consumption of naturally enriched dairy products in amounts similar to habitual intakes of these foods increased the c9,t11 CLA content of plasma and cellular lipids.

Immunonutrition.

PURPOSE OF REVIEW: To outline recent findings on the efficacy of immunonutrients in patients undergoing inflammatory stress due to surgery, infection and cancer. RECENT FINDINGS: Enteral nutrition is more efficacious and poses lower risks than parenteral nutrition. It reduces infection rates and shortens ICU and hospital length of stay of critically ill patients. Beneficial effects of immunonutrition are most apparent in malnourished patients. Perioperative enteral nutrition is more effective than postoperative nutrition. In Crohn disease similar remission rates are achieved with enteral nutrition as with steroids. Glutamine, omega-3 fatty acids and antioxidants exert beneficial influences in diverse patient populations. L-arginine is an important immunonutrient having both beneficial and adverse effects. The former effect occurs in necrotizing enterocolitis; the latter influence is seen in septic patients. The gut plays a major role in whole body amino acid metabolism, particularly arginine homeostasis. Arginase and nitric oxide synthetase compete for arginine within immune cells and play a pivotal role in clinical outcome during infection. In cancer a range of antioxidants are able to ameliorate immunosuppression. Intravenous lipids may be deleterious due to the pro-inflammatory effects of omega-6 fatty acids. Omega-3 fatty acids are anti-inflammatory and combined with medium chain triglyceride (MCT) and olive oil may provide a more efficacious form of intravenous lipid. SUMMARY: Immunonutrition is effective in improving outcome in a wide range of patients when applied enterally, particularly in malnourished individuals. Parenteral immunonutrition carries a higher risk but can be efficacious in selected patient groups for whom enteral nutrition is problematic.

Effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid on immune cell function in healthy humans.

BACKGROUND: Animal studies have suggested that conjugated linoleic acid (CLA), a natural component of ruminant meat and dairy products, may confer beneficial effects on health. However, little information on the effects of CLA on immune function is available, especially in humans. Furthermore, the effects of individual isomers of CLA have not been adequately investigated. OBJECTIVE: This study investigated the effects of supplementing the diet with 3 doses of highly enriched cis-9,trans-11 CLA (0.59, 1.19, and 2.38 g/d) or trans-10,cis-12 CLA (0.63, 1.26, and 2.52 g/d) on immune outcomes in healthy humans. DESIGN: The study had a randomized, double-blind, crossover design. Healthy men consumed 1, 2, and 4 capsules sequentially that contained 80% of either cis-9,trans-11 CLA or trans-10,cis-12 CLA for consecutive 8-wk periods. This regimen was followed by a 6-wk washout and a crossover to the other isomer. RESULTS: Both CLA isomers decreased mitogen-induced T lymphocyte activation in a dose-dependent manner. There was a significant negative correlation between mitogen-induced T lymphocyte activation and the proportions of both cis-9,trans-11 CLA and trans-10,cis-12 CLA in peripheral blood mononuclear cell lipids. However, CLA did not affect lymphocyte subpopulations or serum concentrations of C-reactive protein and did not have any consistent effects on ex vivo cytokine production. CONCLUSION: CLA supplementation results in a dose-dependent reduction in the mitogen-induced activation of T lymphocytes. The effects of cis-9,trans-11 CLA and trans-10,cis-12 CLA were similar, and there was a negative correlation between mitogen-induced T lymphocyte activation and the cis-9,trans-11 CLA and trans-10,cis-12 CLA contents of mononuclear cells.

Opposing effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid on blood lipids in healthy humans.

BACKGROUND: Conjugated linoleic acid (CLA) is reported to have weight-reducing and antiatherogenic properties when fed to laboratory animals. However, the effects of CLA on human health and, in particular, the effects of individual CLA isomers are unclear. OBJECTIVE: This study investigated the effects of 3 doses of highly enriched cis-9,trans-11 (0.59, 1.19, and 2.38 g/d) or trans-10,cis-12 (0.63, 1.26, and 2.52 g/d) CLA preparations on body composition, blood lipid profile, and markers of insulin resistance in healthy men. DESIGN: Healthy men consumed 1, 2, and 4 capsules sequentially, containing either 80% cis-9,trans-11 CLA or 80% trans-10,cis-12 CLA for consecutive 8-wk periods. This phase was followed by a 6-wk washout and a crossover to the other isomer. RESULTS: Body composition was not significantly affected by either isomer of CLA. Mean plasma triacylglycerol concentration was higher during supplementation with trans-10,cis-12 CLA than during that with cis-9,trans-11 CLA, although there was no influence of dose. There were significant effects of both isomer and dose on plasma total cholesterol and LDL-cholesterol concentrations but not on HDL-cholesterol concentration. The ratios of LDL to HDL cholesterol and of total to HDL cholesterol were higher during supplementation with trans-10,cis-12 CLA than during that with cis-9,trans-11 CLA. CLA supplementation had no significant effect on plasma insulin concentration, homeostasis model for insulin resistance, or revised quantitative insulin sensitivity check index. CONCLUSION: Divergent effects of cis-9,trans-11 CLA and trans-10,cis-12 CLA appear on the blood lipid profile in healthy humans: trans-10,cis-12 CLA increases LDL:HDL cholesterol and total:HDL cholesterol, whereas cis-9,trans-11 CLA decreases them.

Incorporation of cis-9,trans-11 or trans-10,cis-12 conjugated linoleic acid into plasma and cellular lipids in healthy men.

This study investigated the incorporation of cis-9,trans-11 conjugated linoleic acid (c9,t11 CLA) and trans-10,cis-12-CLA (t10,c12 CLA) into plasma and peripheral blood mononuclear cell (PBMC) lipids when consumed as supplements highly enriched in these isomers. Healthy men (n = 49, age 31 +/- 8 years) consumed one, two, and four capsules containing approximately 600 mg of either c9,t11 CLA or t10,c12 CLA per capsule for sequential 8 week periods followed by a 6 week washout before consuming the alternative isomer. Both isomers were incorporated in a dose-dependent manner into plasma phosphatidylcholine (PC) (c9,t11 CLA r = 0.779, t10,c12 CLA r = 0.738; P < 0.0001) and cholesteryl ester (CE) (c9,t11 CLA r = 0.706, t10,c12 CLA r = 0.788; P < 0.0001). Only t10,c12 CLA was enriched in plasma nonesterified fatty acids. Both c9,t11 CLA and t10,c12 CLA were incorporated linearly into PBMC total lipids (r = 0.285 and r = 0.273, respectively; P < 0.0005). The highest concentrations of c9,t11 CLA and t10,c12 CLA in PBMC lipids were 3- to 4-fold lower than those in plasma PC and CE. These data suggest that the level of intake is a major determinant of plasma and PBMC CLA content, although PBMCs appear to incorporate both CLA isomers less readily.

Association of n-3 polyunsaturated fatty acids with stability of atherosclerotic plaques: a randomised controlled trial.

BACKGROUND: N-3 polyunsaturated fatty acids (PUFAs) from oily fish protect against death from cardiovascular disease. We aimed to assess the hypothesis that incorporation of n-3 and n-6 PUFAs into advanced atherosclerotic plaques increases and decreases plaque stability, respectively. METHODS: We did a randomised controlled trial of patients awaiting carotid endarterectomy. We randomly allocated patients control, sunflower oil (n-6), or fish-oil (n-3) capsules until surgery. Primary outcome was plaque morphology indicative of stability or instability, and outcome measures were concentrations of EPA, DHA, and linoleic acid in carotid plaques; plaque morphology; and presence of macrophages in plaques. Analysis was per protocol. FINDINGS: 188 patients were enrolled and randomised; 18 withdrew and eight were excluded. Duration of oil treatment was 7-189 days (median 42) and did not differ between groups. The proportions of EPA and DHA were higher in carotid plaque fractions in patients receiving fish oil compared with those receiving control (absolute difference 0.5 [95% CI 0.3-0.7], 0.4 [0.1-0.6], and 0.2 [0.1-0.4] g/100 g total fatty acids for EPA; and 0.3 [0.0-0.8], 0.4 [0.1-0.7], and 0.3 [0.1-0.6] g/100 g total fatty acids for DHA; in plaque phospholipids, cholesteryl esters, and triacylglycerols, respectively). Sunflower oil had little effect on the fatty acid composition of lipid fractions. Fewer plaques from patients being treated with fish oil had thin fibrous caps and signs of inflammation and more plaques had thick fibrous caps and no signs of inflammation, compared with plaques in patients in the control and sunflower oil groups (odds ratio 0.52 [95% CI 0.24-0.89] and 1.19 [1.02-1.57] vs control; 0.49 [0.23-0.90] and 1.16 [1.01-1.53] vs sunflower oil). The number of macrophages in plaques from patients receiving fish oil was lower than in the other two groups. Carotid plaque morphology and infiltration by macrophages did not differ between control and sunflower oil groups. INTERPRETATION: Atherosclerotic plaques readily incorporate n-3 PUFAs from fish-oil supplementation, inducing changes that can enhance stability of atherosclerotic plaques. By contrast, increased consumption of n-6 PUFAs does not affect carotid plaque fatty-acid composition or stability over the time course studied here. Stability of plaques could explain reductions in non-fatal and fatal cardiovascular events associated with increased n-3 PUFA intake.

The effect of graded levels of dietary casein, with or without methionine supplementation, on glutathione concentration in unstressed and endotoxin-treated rats.

Glutathione (GSH) concentration was measured in rats fed either graded levels of dietary casein (experiment 1; 180 g, 120 g, 80 g, or 60 g protein/kg diet) or graded levels of dietary casein, supplemented with methionine to equalize dietary sulfur amino acid content to that seen in an 180 g/kg casein diet supplemented with 0.3 g L-methionine/kg diet (experiment 2; 180 g protein +0.3 g L-methionine, 80 g protein +6.70 g L-methionine, or 60 g protein +7.45 g L-methionine/kg diet). Rats were given an inflammatory challenge by intraperitoneal injection of endotoxin (lipopolysaccharide from Escherichia coli), and were compared with ad libitum and pair-fed controls. Glutathione concentration in various organs (liver, lung, spleen, and thymus) decreased in animals fed the low-protein diets (80 g or 60 g/kg diet). Addition of the sulfur amino acid, methionine, to the low-protein diets restored glutathione concentrations in animals fed ad libitum and prevented the fall in GSH concentration, which occurred in lung, spleen, and thymus in response to the endotoxin. Despite the similarity in the amount of sulfur amino acid consumed between the groups fed the 180 g protein +0.3 g L-methionine and the 60 g protein +7.45 g L-methionine/kg diet, in experiment 2, hepatic GSH concentration significantly increased in the latter group, in animals fed ad libitum and in the endotoxin-treated animals, but not in the pair-fed controls.