n-3 fatty acid supplements in rheumatoid arthritis

n-3 PUFA in CVD: influence of cytokine polymorphism

In their current guidelines cardiac societies recommend the consumption of the two n-3 fatty acids EPA and DHA to prevent cardiovascular complications. Cardiovascular events are reduced by EPA and DHA, because they are antiarrhythmic, mitigate the course of atherosclerosis and stabilise plaque. As atherosclerosis is considered an inflammatory disorder a number of studies have investigated the anti-inflammatory mechanisms of EPA and DHA in a cardiovascular context in human dietary intervention studies. Pro-inflammatory cytokines, or cytokines reflecting inflammatory processes, e.g. IL-1beta, IL-2, IL-6, TNFalpha, platelet-derived growth factor (PDGF)-A and -B and monocyte chemoattractant protein-1 (MCP-1), are reduced by ingestion of EPA and DHA by human subjects. Interestingly, C-reactive protein remains largely unaltered. However, in in vitro and animal models, but less so in human subjects, soluble cytokines reflecting interactions between blood cells and the vessel wall, such as intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, are reduced. Moreover, in contrast to common expectations, oxidative stress seems to be reduced after ingestion of EPA and DHA, at least as indicated by measurement of urinary F(2) isoprostane excretion. Notably, for PDGF-A and -B and for MCP-1 the reduction has been demonstrated to occur at the gene expression level, which indicates that a deliberate change in diet can alter gene expression quantitatively. The precise underlying mechanism, however, remains to be clarified, but might involve PPAR, NF-kappaB and/or the eicosanoid system. The same holds true for the mechanisms by which levels of other cytokines are altered by EPA and DHA.

Dietary fish oil n-3 fatty acids increase regulatory cytokine production and exert anti-inflammatory effects in two murine models of inflammation

The higher incidence of inflammatory diseases in Western countries might be related, in part, to a high consumption of saturated fatty acids and n-6 polyunsaturated fatty acids (PUFA) and an insufficient intake of n-3 fatty acids. The purpose of this study was to examine the effects of dietary n-3 fatty acids on innate and specific immune response and their anti-inflammatory action in models of contact and atopic dermatitis. Balb/C mice were fed for 3 wk either n-6 or n-3 PUFA-fortified diets. After inducing a contact or an atopic dermatitis, immunological parameters were analyzed to evaluate the anti-inflammatory potential of these n-3 PUFA. n-3 PUFA reduced innate and specific immune responses through inhibition of TH1 and TH2 responses, increase of immunomodulatory cytokines such as IL-10, and regulation of gene expression. The inhibition of both kinds of responses was confirmed by the anti-inflammatory effect observed in contact and atopic dermatitis. Reduction in weight, edema, thickness, leukocyte infiltration, and enhancement of antioxidant defenses in the inflamed ears of mice from both models along with the prevention of delayed-type hypersensitivity induced in atopic dermatitis proved n-3 PUFA efficacy. Our data suggest that dietary fish oil-derived n-3 fatty acids have immunomodulatory effects and could be useful in inflammatory disorders.

Management and Therapy of Dry Eye Disease: Report of the Management and Therapy Subcommittee of the International Dry Eye WorkShop (2007)

The members of the Management and Therapy Subcommittee assessed current dry eye therapies. Each member wrote a succinct evidence-based review on an assigned aspect of the topic, and the final report was written after review by and with consensus of all subcommittee members and the entire Dry Eye WorkShop membership. In addition to its own review of the literature, the Subcommittee reviewed the Dry Eye Preferred Practice Patterns of the American Academy of Ophthalmology and the International Task Force (ITF) Delphi Panel on Dry Eye. The Subcommittee favored the approach taken by the ITF, whose recommended treatments were based on level of disease severity. the recommendations of the Subcommittee are based on a modification of the ITF severity grading scheme, and suggested treatments were chosen from a menu of therapies for which evidence of therapeutic effect had been presented.

The impact of long chain n-3 polyunsaturated fatty acid supplementation on inflammation, insulin sensitivity and CVD risk in a group of overweight women with an inflammatory phenotype

BACKGROUND

Inflammation is strongly related to obesity and the risk of cardiovascular disease (CVD). The metabolic benefits of long chain (LC) n-3 polyunsaturated fatty acid (PUFA) may be attributable to its anti-inflammatory properties.

OBJECTIVE

To investigate whether an individual's habitual inflammatory status influences the impact of a LC n-3 PUFA intervention on CVD risk.

DESIGN

The study was a randomized crossover design. Subjects received LC n-3 PUFA capsules or a placebo for 12 weeks, with 4-week washout between phases. Thirty women, in the top and bottom tertiles of baseline sialic acid concentration, formed raised inflammatory status (top, n = 12) and reference (bottom, n = 18) groups. Baseline data were analysed using one-way anova, differences between treatment phases were calculated at each timepoint and analysed using a random effects model.

RESULTS

At baseline, the raised inflammatory status group had significantly higher body mass index and area under the curve (AUC) insulin than the reference group. With LC n-3 PUFA supplementation, both groups showed significantly higher plasma eicosapentaenoic acid and docosahexaenoic acid at 4 and 12 weeks (p < 0.001), and lower triacylglycerols (4 weeks p < 0.01 and 12 weeks p < 0.05). The difference in AUC insulin between the two treatment phases at 12 weeks was significantly greater in the raised inflammatory status group compared to the reference group (p < 0.05). Inflammatory markers were significantly lower after 12 weeks LC n-3 PUFA supplementation compared to baseline (C-reactive protein p < 0.05 and interleukin-6 p < 0.01), but there was no significant group effect.

CONCLUSIONS

Habitual inflammatory status influences the impact of LC n-3 PUFA supplementation, but it is not clear whether the effect of LC n-3 PUFA on AUC insulin is mediated through inflammatory mechanisms.

Different kinetic in incorporation and depletion of n-3 fatty acids in erythrocytes and leukocytes of mice

n-3 PUFA are well known for their anti-inflammatory effects. However, there has been only limited study on the kinetics of incorporation and depletion of n-3 PUFA in immune cells. In the present study we investigated the incorporation and depletion of n-3 PUFA in erythrocytes and leukocytes in mice during a 6-wk feeding period. Over the first 3-wk period (the incorporation period) the mice were fed a special diet with a high n-3/n-6 PUFA ratio. In the following 3-wk period (the depletion period) the mice were fed a standard chow diet. A linear increase of the concentration of EPA and DHA in erythrocyte membranes was observed during the incorporation period, whereas a stagnation was observed after the second week for leukocytes. The level of EPA did not fall to the background level after the depletion period, and the level of DHA was kept almost constant during the depletion period in the erythrocyte membranes. In leukocytes the concentration of both EPA and DHA decreased during the depletion period, but did not reach the background level after the 3-wk depletion. In conclusion, the kinetics of EPA and DHA in the different cells are different. The rate of incorporation is faster than that of depletion for n-3 PUFA. More n-3 PUFA can be incorporated into leukocytes in comparison with erythrocytes. The ratio of n-3/n-6 PUFA is more important than the amount of n-3 FA in changing the FA compositions of membrane lipids.

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.

Fatty acids as modulators of the immune response

Research describing fatty acids as modulators of inflammation and immune responses abounds. Many of these studies have focused on one particular group of fatty acids, omega-3. The data from animal studies have shown that these fatty acids can have powerful anti-inflammatory and immunomodulatory activities in a wide array of diseases (e.g., autoimmunity, arthritis, and infection). However, the evidence from human trials is more equivocal. In this review, a historical framework for understanding how and why fatty acids may affect the immune system is provided. Second, highlights of two recent landmark reports from the Agency for Healthcare Research and Quality are presented. These reports critically evaluate the evidence from human clinical trials of omega-3 fatty acids and rheumatoid arthritis, asthma, and a few other immune-mediated diseases. Third, the data from human clinical trials investigating the impact of various bioactive fatty acids on ex vivo and in vivo immune response are reviewed. Limitations in experimental design and immune assays commonly used are discussed. The discordance between expectation and evidence in this field has been a disappointment. Recommendations for improving both animal-based and human studies are provided.

Polyunsaturated fatty acids and inflammation

The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of mediators (prostaglandins, thromboxanes, leukotrienes and related metabolites). These have inflammatory actions in their own right and also regulate the production of other mediators including inflammatory cytokines. Consumption of long chain n-3 polyunsaturated fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids decrease production of arachidonic acid-derived eicosanoids. These fatty acids also decrease the production of the classic inflammatory cytokines tumour necrosis factor, interleukin-1, and interleukin-6 and the expression of adhesion molecules involved in inflammatory interactions between leukocytes and endothelial cells. These latter effects may occur by eicosanoid-independent mechanisms including modulation of the activation of transcription factors involved in inflammatory processes. The anti-inflammatory actions of long chain n-3 fatty acid-induced effects may be of therapeutic use in conditions with an acute or chronic inflammatory component.

n-3 polyunsaturated fatty acids, inflammation, and inflammatory diseases

Inflammation is part of the normal host response to infection and injury. However, excessive or inappropriate inflammation contributes to a range of acute and chronic human diseases and is characterized by the production of inflammatory cytokines, arachidonic acid-derived eicosanoids (prostaglandins, thromboxanes, leukotrienes, and other oxidized derivatives), other inflammatory agents (e.g., reactive oxygen species), and adhesion molecules. At sufficiently high intakes, long-chain n-3 polyunsaturated fatty acids (PUFAs), as found in oily fish and fish oils, decrease the production of inflammatory eicosanoids, cytokines, and reactive oxygen species and the expression of adhesion molecules. Long-chain n-3 PUFAs act both directly (e.g., by replacing arachidonic acid as an eicosanoid substrate and inhibiting arachidonic acid metabolism) and indirectly (e.g., by altering the expression of inflammatory genes through effects on transcription factor activation). Long-chain n-3 PUFAs also give rise to a family of antiinflammatory mediators termed resolvins. Thus, n-3 PUFAs are potentially potent antiinflammatory agents. As such, they may be of therapeutic use in a variety of acute and chronic inflammatory settings. Evidence of their clinical efficacy is reasonably strong in some settings (e.g., in rheumatoid arthritis) but is weak in others (e.g., in inflammatory bowel diseases and asthma). More, better designed, and larger trials are required to assess the therapeutic potential of long-chain n-3 PUFAs in inflammatory diseases. The precursor n-3 PUFA alpha-linolenic acid does not appear to exert antiinflammatory effects at achievable intakes.

Omega-3 fatty acids (fish oil) as an anti-inflammatory: an alternative to nonsteroidal anti-inflammatory drugs for discogenic pain

BACKGROUND

The use of NSAID medications is a well-established effective therapy for both acute and chronic nonspecific neck and back pain. Extreme complications, including gastric ulcers, bleeding, myocardial infarction, and even deaths, are associated with their use. An alternative treatment with fewer side effects that also reduces the inflammatory response and thereby reduces pain is believed to be omega-3 EFAs found in fish oil. We report our experience in a neurosurgical practice using fish oil supplements for pain relief.

METHODS

From March to June 2004, 250 patients who had been seen by a neurosurgeon and were found to have nonsurgical neck or back pain were asked to take a total of 1200 mg per day of omega-3 EFAs (eicosapentaenoic acid and decosahexaenoic acid) found in fish oil supplements. A questionnaire was sent approximately 1 month after starting the supplement.

RESULTS

Of the 250 patients, 125 returned the questionnaire at an average of 75 days on fish oil. Seventy-eight percent were taking 1200 mg and 22% were taking 2400 mg of EFAs. Fifty-nine percent discontinued to take their prescription NSAID medications for pain. Sixty percent stated that their overall pain was improved, and 60% stated that their joint pain had improved. Eighty percent stated they were satisfied with their improvement, and 88% stated they would continue to take the fish oil. There were no significant side effects reported.

CONCLUSIONS

Our results mirror other controlled studies that compared ibuprofen and omega-3 EFAs demonstrating equivalent effect in reducing arthritic pain. omega-3 EFA fish oil supplements appear to be a safer alternative to NSAIDs for treatment of nonsurgical neck or back pain in this selective group.

Effect of fish oil enriched enteral diet on inflammatory bowel disease tissues in organ culture: differential effects on ulcerative colitis and Crohn's disease

AIM

To investigate the influence of fish oil enriched enteral diet on intestinal tissues taken from Crohn's disease (CD), ulcerative colitis (UC) and non-inflamed non-IBD control patients in vitro.

METHODS

Colonoscopic biopsies from patients with active CD (n = 4), active UC (n = 7), and non-inflamed non-IBD control patients (n = 4) were incubated (three dilutions of 1:20, 1:10, and 1:5) with Waymouth's culture medium and enteral elemental diet (EO28, SHS, Liverpool, UK) modified in the fatty acid composition with fish oil (EF) in an organ culture system for 24 h. In each experimental set-up, incubation with Waymouth's medium alone as control was included. Tissue viability was assessed by adding bromodeoxyuridine (BrdU) to the culture fluid and immunohistochemically staining for BrdU uptake. Cytokine ratio of IL-1ra/IL-1beta (low ratio indicative of inflammation) and production of those cytokines as a percentage of medium control were assayed in the culture supernatant.

RESULTS

Incubation of CD-affected tissue with EF (1:20, 1:10, and 1:5) modestly and non-significantly increased IL-1ra/IL-1beta ratio as compared with medium control (CD 39.1+/-16.1; 26.5+/-7.8, 47.1+/-16.8 vs control 13.0+/-2.2), but incubation of UC-affected tissues increased IL-1ra/IL-1beta ratio significantly in all three dilutions (UC 69.1+/-32.2, P<0.05; 76.1+/-36.4, P = 0.05; 84.5+/-37.3, P<0.02; vs control 10.2+/-3.7). Incubation of non-inflamed non-IBD control tissue did not increase the IL-1ra/IL-1beta ratio in any dilution compared to medium control (69.3+/-47.0, 54.1+/-30.6, 79.4+/-34.0 vs control 76.1+/-37.3). Average percentage production of IL-1beta indexed against medium control was significantly less in UC after EF incubation as compared with CD (UC 24.0+/-4.8 vs CD 51.8+/-8.1; P<0.05). Average percentage production of IL-1ra was markedly higher in UC (135.9+/-3.4) than that in control patients (36.5+/-4.3) (P<0.0001).

CONCLUSION

IBD tissues, after incubation with elemental diet modified in its fatty acid composition with fish oil, show an increase in IL-1ra/IL-1beta cytokine ratio. This effect of omega-3 fatty acid modulation is significantly more marked in UC compared with CD and is accompanied by both a reduction of IL-1beta and increase of IL-1ra. The positive direct anti-inflammatory effect of elemental diet with fish oil in tissue affected with UC suggests dietary treatment of UC may be possible.

Pathogenesis of degenerative temporomandibular joint arthritides

Over the past decade, remarkable progress has been made in the study of molecular mechanisms involved in degenerative temporomandibular joint arthritides. Based on recent findings, models of degenerative temporomandibular joint disease predict that mechanical loads trigger a cascade of molecular events leading to disease in susceptible individuals. These events involve the production or release of free radicals, cytokines, fatty acid catabolites, neuropeptides, and matrix-degrading enzymes. Under normal circumstances, these molecules may be involved in the remodeling of articular tissues in response to changing functional demands. However, if functional demands exceed the adaptive capacity of the temporomandibular joint or if the affected individual is susceptible to maladaptive responses, then a disease state will ensue. An individual's susceptibility to degenerative temporomandibular joint disease may be determined by several factors, including genetic backdrop, sex, age, and nutritional status. It is hoped that, by furthering our understanding of the molecular events that underlie degenerative temporomandibular joint diseases, improved diagnostics and effective therapies for these debilitating conditions will be developed.

Inhibition of osteoporosis in autoimmune disease prone MRL/Mpj-Fas(lpr) mice by N-3 fatty acids

OBJECTIVE

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease involving the breakdown of cartilage and juxta-articular bone, which is often accompanied by decreased bone mineral density (BMD) and increased risk of fracture. Anti-inflammatory omega-3 fatty acids may prevent arthritis and bone loss in MRL/lpr mice model of arthritis and in humans.

METHODS

In this study, the effect of long term feeding of 10% dietary n-3 (fish oil (FO)) and n-6 (corn oil (CO)) fatty acids begun at 6 weeks of age on bone mineral density (BMD) in different bone regions in an MRL/lpr female mouse model of RA was measured at 6, 9, and 12 months of age by dual energy x-ray absorptiometry (DEXA). After sacrificing the mice at 12 months of age, antioxidant enzyme activities were measured in spleen, mRNA for receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) was measured by RT-PCR in lymph nodes, and synovitis was measured in leg joints.

RESULTS

At 6, 9 and 12 months of age, BMD was significantly higher (p < 0.05) in distal femur, proximal tibia, and lumbar spine of FO fed mice than those of CO fed mice. Spleen catalase (CAT) and superoxide dismutase (SOD) activities were also significantly higher (p < 0.01) in FO fed mice than in CO fed mice. Histology of knee joints revealed mild synovitis in CO fed mice, which was not present in FO fed mice. RT-PCR analysis of lymph nodes revealed decreased RANKL mRNA (p < 0.001) expression and enhanced OPG mRNA expression (p < 0.01) in FO fed mice compared to CO fed mice.

CONCLUSIONS

These results suggest beneficial effects of long-term FO feeding in maintaining higher BMD and lower synovitis in this mouse model. These beneficial effects may be due, in part, to increased activity of antioxidant enzymes, decreased expression of RANKL, and increased expression of OPG in FO fed mice thereby altering the RANKL/OPG ratio. These significant beneficial effects on BMD suggest that FO may serve as an effective dietary supplement to prevent BMD loss in patients with RA.

Preoperative oral supplementation with long-chain Omega-3 fatty acids beneficially alters phospholipid fatty acid patterns in liver, gut mucosa, and tumor tissue

BACKGROUND

The uptake of omega-3 polyunsaturated fatty acids (PUFAs) into the liver, gut mucosa, and tumor tissue and plasma levels after preoperative administration of supplemented enteral nutrition was investigated in patients with malignancies of the upper gastrointestinal tract. The objective of the study was to evaluate the incorporation of preoperatively administrated PUFAs, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) into cell phospholipids.

METHODS

Patients undergoing major gastrointestinal surgery (n = 40) were prospectively randomized to receive a PUFA-supplemented liquid oral diet 5 days preoperatively or an isocaloric control diet. The planned diet intake was 1000 mL/d providing 3.7 g of PUFA. The diet was given in addition to the usual hospital diet. The phospholipid fractions in plasma were analyzed on the day of surgery. Tissue samples of liver, gut mucosa (small intestine), and tumor were taken during surgery and homogenized. EPA and DHA content was analyzed using liquid gas chromatography.

RESULTS

Both patient groups (PUFA group: n = 20; control group: n = 20) were similar in age, weight, and surgical procedures. As compared with the control group, the PUFA group had significantly increased levels of EPA in liver tissue (0.4 vs 1.3 weight %), gut mucosa (0.3 vs 1.0 weight %), and tumor tissue (0.3 vs 0.8 weight %). Also, the DHA levels in the PUFA group were significantly higher than the control group: liver tissue (4.1 vs 7.5 weight %), gut mucosa (2.1 vs 3.7 weight %) and tumor tissue (1.9 vs 4.2 weight %).

CONCLUSIONS

This study suggests that administration of PUFA-enriched diets leads to increased incorporation of EPA and DHA not only in liver and gut mucosa tissue, but also in tumor tissue in patients with solid gastrointestinal tumors. Thus, preoperative administration of oral PUFA-enriched diets could have an impact on the postoperative inflammatory response after major abdominal surgery.

Fat intake and composition of fatty acids in serum phospholipids in a randomized, controlled, Mediterranean dietary intervention study on patients with rheumatoid arthritis

BACKGROUND

We have previously reported that rheumatoid arthritis patients, who adopted a modified Cretan Mediterranean diet, obtained a reduction in disease activity and an improvement in physical function and vitality. This shift in diet is likely to result in an altered intake of fatty acids. Therefore, the objective of the present study was to examine the dietary intake of fatty acids, as well as the fatty acid profile in serum phospholipids, during the dietary intervention study presented earlier.

RESULTS

From baseline to the end of the study, changes in the reported consumption of various food groups were observed in the Mediterranean diet group. The change in diet resulted in a number of differences between the Mediterranean diet group and the control diet group regarding the fatty acid intake. For instance, a lower ratio of n-6 to n-3 fatty acids was observed in the Mediterranean diet group, both assessed by diet history interviews (dietary intake) and measured in serum phospholipids. Moreover, the patients in the Mediterranean diet group that showed a moderate or better clinical improvement during the study (diet responders), had a higher reported intake of n-3 fatty acids and a lower ratio of n-6 to n-3 fatty acids compared to the patients with minor or no improvement. Also the fatty acid profile in serum phospholipids differed in part between the diet responders and the diet non-responders.

CONCLUSION

The changes in the fatty acid profile, indicated both by dietary assessments and through fatty acids in s-phospholipids may, at least in part, explain the beneficial effects of the Cretan Mediterranean diet that we have presented earlier.

Fatty acids from lipids of marine organisms: molecular biodiversity, roles as biomarkers, biologically active compounds, and economical aspects

Because of their characteristic living environments, marine organisms produce a variety of lipids. Fatty acids constitute the essential part of triglycerides and wax esters, which are the major components of fats and oils. Nevertheless, phospholipids and glycolipids have considerable importance and will be taken into account, especially the latter compounds that excite increasing interest regarding their promising biological activities. Thus, in addition to the major polyunsaturated fatty acids (PUFA) such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, a great number of various fatty acids occur in marine organisms, e.g. saturated, mono- and diunsaturated, branched, halogenated, hydroxylated, methoxylated, non-methylene-interrupted. Various unprecedented chemical structures of fatty acids, and lipid-containing fatty acids, have recently been discovered, especially from the most primitive animals such as sponges and gorgonians. This review of marine lipidology deals with recent advances in the field of fatty acids since the end of the 1990s. Different approaches will be followed, mainly developing biomarkers of trophic chains in marine ecosystems and of chemotaxonomic interest, reporting new structures, especially those with biological activities or biosynthetic interest. An important part of this review will be devoted to the major PUFA, their relevance to health and nutrition, their biosynthesis, their sources (usual and promising) and market.

Gestational age and birth weight in relation to n-3 fatty acids among Inuit (Canada)

Seafood consumption during pregnancy carries both benefits (high n-3 FA intake) and risks (exposure to environmental contaminants) for the developing fetus. We determined the impacts of marine n-3 FA and environmental contaminants on gestational age (GA) of Nunavik women and the anthropometric characteristics of their newborns. FA and contaminant (polychlorinated biphenyls and mercury) concentrations were measured in cord plasma of Nunavik newborns (n = 454) and compared with those of a group of newborns (n = 29) from southern Québec. Data were collected from hospital records and birth certificates. In Nunavik newborns, arachidonic acid (AA) was two times lower (P < 0.0001), whereas DHA concentration, the sigman-3 / sigman-6 ratio, and the percentage of n-3 highly unsaturated FA (HUFA) (of the total HUFA) were three times higher (P < 0.0001) compared with southern Québec newborns. After controlling for confounders, GA and birth weight were higher by 5.4 d [95% confidence interval (CI): 0.7-10.1] and 77 g (95% CI: -64 to 217) in the third tertile of percentage of n-3 HUFA (of the total HUFA) as compared with the first tertile. There was no evidence that contaminants had negative effects on GA or birth weight. In this seafood-eating population, an increase in the proportion of n-3 HUFA (of the total HUFA), measured in umbilical cord plasma phospholipids, was associated with a significantly longer GA.

Effects of dietary n-3 polyunsaturated fatty acids on T-cell membrane composition and function

Dietary n-3 PUFA have been shown to attenuate T-cell-mediated inflammation, in part, by suppressing T-cell activation and proliferation. n-3 PUFA have also been shown to promote apoptosis, another important mechanism for the prevention of chronic inflammation by maintaining T-cell homeostasis through the contraction of populations of activated T cells. Recent studies have specifically examined Fas death receptor-mediated activation-induced cell death (AICD), since it is the form of apoptosis associated with peripheral T-cell deletion involved in immunological tolerance and T-cell homeostasis. Data from our laboratory indicate that n-3 PUFA promote AICD in T helper 1 polarized cells, which are the mediators of chronic inflammation. Since Fas and components of the death-inducing signaling complex are recruited to plasma membrane microdomains (rafts), the effect of dietary n-3 PUFA on raft composition and resident protein localization has been the focus of recent investigations. Indeed, there is now compelling evidence that dietary n-3 PUFA are capable of modifying the composition of T-cell membrane microdomains (rafts). Because the lipids found in membrane microdomains actively participate in signal transduction pathways, these results support the hypothesis that dietary n-3 PUFA influence signaling complexes and modulate T-cell cytokinetics in vivo by altering T-cell raft composition.

Supplementation of fish oil and olive oil in patients with rheumatoid arthritis

OBJECTIVE

This study evaluated whether supplementation with olive oil could improve clinical and laboratory parameters of disease activity in patients who had rheumatoid arthritis and were using fish oil supplements.

METHODS

Forty-three patients (34 female, 9 male; mean age = 49 +/- 19y) were investigated in a parallel randomized design. Patients were assigned to one of three groups. In addition to their usual medication, the first group (G1) received placebo (soy oil), the second group (G2) received fish oil omega-3 fatty acids (3 g/d), and the third group (G3) received fish oil omega-3 fatty acids (3 g/d) and 9.6 mL of olive oil. Disease activity was measured by clinical and laboratory indicators at the beginning of the study and after 12 and 24 wk. Patients' satisfaction in activities of daily living was also measured.

RESULTS

There was a statistically significant improvement (P < 0.05) in G2 and G3 in relation to G1 with respect to joint pain intensity, right and left handgrip strength after 12 and 24 wk, duration of morning stiffness, onset of fatigue, Ritchie's articular index for pain joints after 24 wk, ability to bend down to pick up clothing from the floor, and getting in and out of a car after 24 wk. G3, but not G2, in relation to G1 showed additional improvements with respect to duration of morning stiffness after 12 wk, patient global assessment after 12 and 24 wk, ability to turn faucets on and off after 24 wk, and rheumatoid factor after 24 wk. In addition, G3 showed a significant improvement in patient global assessment in relation to G2 after 12 wk.

CONCLUSIONS

Ingestion of fish oil omega-3 fatty acids relieved several clinical parameters used in the present study. However, patients showed a more precocious and accentuated improvement when fish oil supplements were used in combination with olive oil.

Dietary risk factors for rheumatic diseases

PURPOSE OF REVIEW

Recent scientific data illuminate the dietary link to rheumatic disorders. This review summarizes recently published articles on the dietary link to rheumatoid arthritis, gout, and osteoarthritis.

RECENT FINDINGS

A prospective study suggests that higher intakes of meat and total protein as well as lower intakes of fruit, vegetables, and vitamin C are associated with an increased risk of inflammatory polyarthritis or rheumatoid arthritis. Several studies suggest that the Mediterranean-type diet or its main components may have protective effects on the development or severity of rheumatoid arthritis. A recent prospective study investigated several purported dietary factors for gout and confirmed some of the long-standing suspicions (red meats, seafood, beer, and liquor), exonerated others (total protein, wine, and purine-rich vegetables), and also identified potentially new protective factors (dairy products). Recent double-blind, randomized, placebo-controlled studies suggest that antioxidant vitamins (vitamin E, vitamin C, beta-carotene, and retinol) do not halt the progression of symptomatic knee osteoarthritis, as was previously suggested.

SUMMARY

Because diet is an unavoidable universal exposure for people, even a small effect that can be achieved by dietary manipulation may produce a large impact on the population's health. As the evidence on the role of dietary factors in rheumatic disorders grows it becomes increasingly important for clinicians and investigators in the field of rheumatology to familiarize themselves with the relevant data and appropriately apply them to clinical and public health practice.

Eicosapentaenoic acid prevents lipopolysaccharide-stimulated DNA binding of activator protein-1 and c-Jun N-terminal kinase activity

Activator protein-1 (AP-1) is a transcription factor that plays an important role in regulating the expression of proinflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha). Many studies have shown that fish oil supplementation inhibits TNF-alpha production in mice and humans; however, the mechanisms remain unclear. In this study, the effects of eicosapentaenoic acid (EPA), a major n-3 fatty acid in fish oil, on lipopolysaccharide (LPS)-stimulated activation of AP-1 were investigated in human monocytic THP-1 cells. The results demonstrated that AP-1 DNA binding activity stimulated by LPS was suppressed by preincubating cells with EPA. Lipopolysaccharide-stimulated increase of c-Jun and c-Fos protein levels was also attenuated by EPA pretreatment. In addition, EPA pretreatment decreased LPS-induced c-Jun phosphorylation and c-Jun N-terminal kinase (JNK) activation. The results suggest that suppression of TNF-alpha expression by EPA may be partly mediated by its inhibitory effect on AP-1 activation.

Intake of n-3 fatty acids from fish does not lower serum concentrations of C-reactive protein in healthy subjects

OBJECTIVE

High-sensitivity C-reactive protein (CRP), a marker of systemic inflammation, is a powerful predictor of cardiovascular risk. We hypothesised that n-3 fatty acids reduce underlying inflammatory processes and consequently CRP concentrations in healthy middle-aged subjects.

DESIGN

Placebo-controlled, double-blind study.

SUBJECTS

A total of 43 men and 41 postmenopausal women aged 50-70 y. Before and after intervention, we measured serum CRP concentrations with an enzyme immunoassay.

INTERVENTIONS

Capsules with either 3.5 g/day fish oil (1.5 g/day n-3 fatty acids) or placebo for 12 weeks.

RESULTS

The median CRP change in the fish oil group did not significantly differ from that in the placebo group (0.01 vs -0.17 mg/l, P = 0.057).

CONCLUSION

The currently available data--including ours--do not support that beneficial effects on CRP are involved in a mechanism explaining the protective effect on heart disease risk of n-3 fatty acids as present in fish.

Dietary Docosahexaenoic Acid Suppresses T Cell Protein Kinase Cθ Lipid Raft Recruitment and IL-2 Production

To date, the proximal molecular targets through which dietary n-3 polyunsaturated fatty acids (PUFA) suppress the inflammatory process have not been elucidated. Because cholesterol and sphingolipid-enriched rafts have been proposed as platforms for compartmentalizing dynamically regulated signaling assemblies at the plasma membrane, we determined the in vivo effects of fish oil and highly purified docosahexaenoic acid (DHA; 22:6n-3) on T cell microdomain lipid composition and the membrane subdomain distribution of signal-transducing molecules (protein kinase C (PKC)theta;, linker for activation of T cells, and Fas/CD95), before and after stimulation. Mice were fed diets containing 5 g/100 g corn oil (control), 4 g/100 g fish oil (contains a mixture of n-3 PUFA) plus 1 g/100 g corn oil, or 4 g/100 g corn oil plus 1 g/100 g DHA ethyl ester for 14 days. Dietary n-3 PUFA were incorporated into splenic T cell lipid raft and soluble membrane phospholipids, resulting in a 30% reduction in raft sphingomyelin content. In addition, polyclonal activation-induced colocalization of PKCtheta; with lipid rafts was reduced by n-3 PUFA feeding. With respect to PKCtheta; effector pathway signaling, both AP-1 and NF-kappaB activation, IL-2 secretion, and lymphoproliferation were inhibited by fish oil feeding. Similar results were obtained when purified DHA was fed. These data demonstrate for the first time that dietary DHA alters T cell membrane microdomain composition and suppresses the PKCtheta; signaling axis.

Dietary fat and protein interact in suppressing neuropathic pain-related disorders following a partial sciatic ligation injury in rats

Chronic neuropathic sensory disorders (CNSD) of rats receiving a partial sciatic nerve ligation injury (the PSL model) are suppressed by dietary soy protein. Although previously shown to modify nociceptive behavior in acute pain models, dietary fat has never been tested for its putative analgesic properties in chronic pain states. Here we tested the role of dietary fat, protein and fat/protein interactions in the development of tactile allodynia and heat hyperalgesia in PSL-injured rats. Male Wistar rats were fed nine different diets, comprising of three proteins (soy, casein and albumin) and three fats (corn, soy and canola) for a week preceding PSL injury and for 2 weeks thereafter. Rats' responses to tactile and noxious heat stimuli were tested before surgery and 3, 7 and 14 days afterwards. Tactile and heat sensory abnormalities following PSL injury were significantly different among the nine dietary groups. Consumption of corn and soy fats suppressed the levels of tactile and heat allodynia and hyperalgesia, whereas consumption of soy and casein proteins was associated with lower levels of heat hyperalgesia but not tactile allodynia. A significant fat/protein interaction was found for the heat but not tactile stimuli. We conclude that dietary fat is a significant independent predictor of levels of neuropathic sensory disorders in rats and that this effect is accentuated by dietary protein. The mechanisms by which fat suppresses neuropathic disorders have yet to be determined.

Polyunsaturated Fatty Acid Regulation of Gene Expression

Polyunsaturated fatty acids (PUFAs), specifically the n-3 series, have been implicated in the prevention of various human diseases, including obesity, diabetes, coronary heart disease and stroke, and inflammatory and neurologic diseases. PUFAs function mainly by altering membrane lipid composition, cellular metabolism, signal transduction, and regulation of gene expression. PUFAs regulate the expression of genes in various tissues, including the liver, heart, adipose tissue, and brain. The role of transcription factors such as SREBP1c and nuclear receptors such as PPAR-alpha, HNF-4alpha, and LXRalpha in mediating the nuclear effects of PUFAs are addressed.

EFA supplementation in children with inattention, hyperactivity, and other disruptive behaviors

This pilot study evaluated the effects of supplementation with PUFA on blood FA composition and behavior in children with Attention-Deficit/Hyperactivity Disorder (AD/HD)-like symptoms also reporting thirst and skin problems. Fifty children were randomized to treatment groups receiving either a PUFA supplement providing a daily dose of 480 mg DHA, 80 mg EPA, 40 mg arachidonic acid (AA), 96 mg GLA, and 24 mg alpha-tocopheryl acetate, or an olive oil placebo for 4 mon of double-blind parallel treatment. Supplementation with the PUFA led to a substantial increase in the proportions of EPA, DHA, and alpha-tocopherol in the plasma phospholipids and red blood cell (RBC) total lipids, but an increase was noted in the plasma phospholipid proportions of 18:3n-3 with olive oil as well. Significant improvements in multiple outcomes (as rated by parents) were noted in both groups, but a clear benefit from PUFA supplementation for all behaviors characteristic of AD/HD was not observed. For most outcomes, improvement of the PUFA group was consistently nominally better than that of the olive oil group; but the treatment difference was significant, by secondary intent-to-treat analysis, on only 2 out of 16 outcome measures: conduct problems rated by parents (-42.7 vs. -9.9%, n = 47, P = 0.05), and attention symptoms rated by teachers (-14.8 vs. +3.4%, n = 47, P = 0.03). PUFA supplementation led to a greater number of participants showing improvement in oppositional defiant behavior from a clinical to a nonclinical range compared with olive oil supplementation (8 out of 12 vs. 3 out of 11, n = 33, P = 0.02). Also, significant correlations were observed when comparing the magnitude of change between increasing proportions of EPA in the RBC and decreasing disruptive behavior as assessed by the Abbreviated Symptom Questionnaire (ASQ) for parents (r = -0.38, n = 31, P < 0.05), and for EPA and DHA in the RBC and the teachers' Disruptive Behavior Disorders (DBD) Rating Scale for Attention (r = -0.49, n = 24, P < 0.05). Interestingly, significant correlations were observed between the magnitude of increase in alpha-tocopherol concentrations in the RBC and a decrease in scores for all four subscales of the teachers' DBD (Hyperactivity, r = -0.45; Attention, r= -0.60; Conduct, r = -0.41; Oppositional/Defiant Disorder, r = -0.54; n = 24, P < 0.05) as well as the ASQ for teachers (r = -0.51, n = 24, P < 0.05). Thus, the results of this pilot study suggest the need for further research with both n-3 FA and vitamin E in children with behavioral disorders.

Nutrient supplementation with polyunsaturated fatty acids and micronutrients in rheumatoid arthritis: clinical and biochemical effects

OBJECTIVE

To investigate in a double-blind placebo-controlled, parallel group study, the effects of a nutrient supplement, containing, among other ingredients, the omega-3 fatty acids eicosapentaenoic acid (1.4 g EPA), docosahexaenoic acid (0.211 g DHA), omega-6 fatty acid gamma-linolenic acid (0.5 g GLA) and micronutrients in patients with active rheumatoid arthritis (RA).

DESIGN, SUBJECTS AND INTERVENTION

RA patients were randomized to receive either daily liquid nutrient supplementation or placebo for 4 months. The primary end point was the change in tender joint count at 2 and 4 months. Other clinical variables included swollen joint count, visual analogue scales for pain and disease activity, grip strength, functionality score and morning stiffness. Biochemical parameters included plasma concentrations of PUFA and vitamins C and E.

SETTING

Outpatient university clinic.

RESULTS

In all, 66 patients enrolled, 55 completed the study. No significant change from baseline in tender joint count or any of the other clinical parameters was detected in either group. Patients receiving nutrient supplementation, but not those receiving placebo, had significant increases in plasma concentrations of vitamin E (P=0.015), and EPA, DHA and docosapentaenoic acid concomitant with decreases of arachidonic acid (P=0.01). Intergroup differences for PUFA and vitamin E were significantly different (P=0.01 and 0.03, respectively).

CONCLUSIONS

This double-blind, placebo-controlled study in RA patients did not show superior clinical benefit of daily nutrient supplementation with EPA, GLA and micronutrients at the doses tested as compared to placebo. The study adds information regarding doses of omega-3 fatty acids, below which anti-inflammatory effects in RA are not seen.

Dietary n-3 polyunsaturated fatty acids promote activation-induced cell death in Th1-polarized murine CD4+ T-cells

Dietary n-3 PUFAs have been shown to attenuate T-cell-mediated inflammation. To investigate whether dietary n-3 PUFAs promote activation-induced cell death (AICD) in CD4+ T-cells induced in vitro to a polarized T-helper1 (Th1) phenotype, C57BL/6 mice were fed diets containing either 5% corn oil (CO; n-6 PUFA control) or 4% fish oil (FO) plus 1% CO (n-3 PUFA) for 2 weeks. Splenic CD4+ T-cells were cultured with alpha-interleukin-4 (alphaIL-4), IL-12, and IL-2 for 2 days and then with recombinant (r) IL-12 and rIL-2 for 3 days in the presence of diet-matched homologous mouse serum (HMS) to prevent loss of cell membrane fatty acids, or with fetal bovine serum. After polarization, Th1 cells were reactivated and analyzed for interferon-gamma and IL-4 by intracellular cytokine staining and for apoptosis by Annexin V/propidium iodide. Dietary FO enhanced Th1 polarization by 49% (P = 0.0001) and AICD by 24% (P = 0.0001) only in cells cultured in the presence of HMS. FO enhancement of Th1 polarization and AICD after culture was associated with the maintenance of eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3) in plasma membrane lipid rafts. In conclusion, n-3 PUFAs enhance the polarization and deletion of proinflammatory Th1 cells, possibly as a result of alterations in membrane microdomain fatty acid composition.

Early modifications of fatty acid composition in plasma phospholipids, platelets and mononucleates of healthy volunteers after low doses of n-3 polyunsaturated fatty acids

OBJECTIVES

Although previous data suggested that only doses of 4 g/day or higher of n-3 polyunsaturated fatty acids (PUFA) have had a beneficial effect in the prevention of atherosclerosis and cardiovascular diseases, the GISSI-Prevenzione Study in a 3-year trial showed that 1 g/day reduced total and cardiovascular mortality in over 11,000 post-infarction patients. The aim of this study was to investigate the time course and the extent of incorporation of n-3 fatty acids in plasma and blood cells after 1 g/day of n-3 PUFA, the dose effective in the GISSI-Prevenzione in comparison with higher doses.

METHODS

Thirty-six healthy volunteers were given 1, 2 and 4 g/day of n-3 PUFA ethyl esters for 12 weeks, followed by a 4-week washout. Blood was collected at weeks 0, 1, 2, 4, 8, 12 and 16 and used for lipid profile analysis and measurement of fatty acid composition in plasma phospholipids, platelets and mononucleates.

RESULTS

Total n-3 PUFA increased by 2.0-, 2.2- and 2.9-fold versus baseline after 12-week treatment with 1, 2 and 4 g respectively. A statistically significant raise of total n-3 PUFA was seen in platelets and mononucleates. Among individual n-3 PUFA, 22:5 n-3 was enriched early and dose dependently in plasma phospholipids, platelets and mononucleates; the raise of 22:6 n-3 was less marked especially in platelets and mononucleates.

CONCLUSIONS

One gram per day of n-3 PUFA induces fast (within 1 week) and striking changes in blood composition of PUFA that may well explain their beneficial effects against cardiovascular diseases.

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.

Subchondral bone in osteoarthritis: a biologic link with articular cartilage leading to abnormal remodeling

PURPOSE OF REVIEW

This review deals with new findings highlighting the concept of cross-talk between subchondral bone tissue and articular cartilage that may be crucial for the initiation and/or progression of osteoarthritis. In this review, new factors either produced by subchondral bone tissue or modifying osteoblast metabolism, yet implicated in osteoarthritis, are discussed.

RECENT FINDINGS

The development of cartilage degeneration is concomitant with subchondral bone thickness in osteoarthritis, whereas it is related to higher subchondral bone activity and dysregulation in the synthesis of bone proteins. As an immediate consequence, homotrimers of type 1 collagen are formed that could lead to undermineralization of this tissue. This dysregulation also leads to abnormal production of different factors by osteoblasts such as prostaglandins, leukotrienes, and growth factors. Because microcracks or neovascularization provide a link between the subchondral bone tissue and articular cartilage, these factors could contribute to the abnormal remodeling of osteoarthritic cartilage.

SUMMARY

These findings have an immediate implication for research because new tools need to be developed to study the subchondral bone-cartilage functional unit. Moreover, it could lead to a possible cure for osteoarthritis because this pathology should be considered both a bone and cartilage disease.

Dietary (n-3) polyunsaturated fatty acids remodel mouse T-cell lipid rafts

In vitro evidence indicates that (n-3) polyunsaturated fatty acids (PUFA) suppress T-cell activation in part by displacing proteins from lipid rafts, specialized regions within the plasma membrane that play an important role in T-cell signal transduction. However, the ability of (n-3) PUFA to influence membrane microdomains in vivo has not been examined to date. Therefore, we compared the effect of dietary (n-3) PUFA on raft (liquid ordered) vs. soluble (liquid disordered) microdomain phospholipid composition in mouse T cells. Mice were fed diets containing either 5 g/100 g corn oil (control) or 4 g/100 g fish oil [contains (n-3) PUFA] + 1 g/100 g corn oil for 14 d. Splenic T-cell lipid rafts were isolated by density gradient centrifugation. Raft sphingomyelin content (mol/100 mol) was decreased (P < 0.05) in T cells isolated from (n-3) PUFA-fed mice. Dietary (n-3) PUFA were selectively incorporated into T-cell raft and soluble membrane phospholipids. Phosphatidylserine and glycerophosphoethanolamine, which are highly localized to the inner cytoplasmic leaflet, were enriched to a greater extent with unsaturated fatty acids compared with sphingomyelin, phosphatidylinositol and glycerophosphocholine. These data indicate for the first time that dietary (n-3) PUFA differentially modulate T-cell raft and soluble membrane phospholipid and fatty acyl composition.

Modulatory effect of omega-3 polyunsaturated fatty acids on osteoblast function and bone metabolism

Recent investigations indicate that the type and amount of polyunsaturated fatty acids (PUFA) influence bone formation in animal models and osteoblastic cell functions in culture. In growing rats, supplementing the diet with omega-3 PUFA results in greater bone formation rates and moderates ex vivo prostaglandin E(2) production in bone organ cultures. A protective effect of omega-3 PUFA on minimizing bone mineral loss in ovariectomized rats has also been reported. The actions of omega-3 fatty acids on bone formation appear to be linked to altering osteoblast functions. Herein we describe experiments with MC3T3-E1 osteoblast-like cells that support findings in vivo where omega-3 PUFA modulated COX-2 protein expression, reduced prostaglandin E(2) production, and increased alkaline phosphatase activity. Other studies indicate that the dietary source of PUFA may affect protein expression of Cbfa1 and nodule formation in fetal rat calvarial cells.

Dietary fish oil impairs primary host resistance against Listeria monocytogenes more than the immunological memory response

The primary objective of this study was to determine whether dietary (n-3) polyunsaturated fatty acids (PUFA) impair the ability of mice to generate an immunological memory response against the bacterial pathogen, Listeria monocytogenes. Weanling BALB/c female mice were fed for 28 d one of two semipurified high fat diets containing either lard or refined menhaden fish oil, rich in long-chain (n-3) PUFA. Mice were immunized with 10(4) or 10(3) colony forming units (cfu) bacteria. Thirty-five days later, these immune mice and age-matched naïve (i.e., unimmunized) mice were challenged with 10(5) cfu bacteria. Three days postchallenge, bacterial clearance was determined. Compared with lard-fed mice, naïve mice in the fish oil treatment group had higher bacterial loads in their liver and spleen (P < 0.001). When mice were immunized with 10(4) cfu bacteria before rechallenge with 10-fold more bacteria, both lard- and fish oil-fed mice had significantly lower bacterial loads in their liver and spleen (e.g., approximately 2 log(10); P < 0.001) compared with their naïve counterparts. However, when the immunization dose was reduced to 10(3) bacteria, a modest diet treatment effect was observed, such that compared with immune lard-fed mice, immune fish oil-fed mice had significantly greater bacterial loads in their liver and spleen (i.e., approximately 0.5 log(10); P < 0.01). These data demonstrate for the first time that although dietary (n-3) PUFA can significantly impair host resistance to a primary as well as a secondary L. monocytogenes infection, the impairment of the immunological memory response is much less severe.

Nutritional management of rheumatoid arthritis: a review of the evidence

Rheumatoid arthritis (RA) is a debilitating disease and is associated with increased risk of cardiovascular disease and osteoporosis. Poor nutrient status in RA patients has been reported and some drug therapies, such as nonsteroidal anti-inflammatory drugs (NSAIDs), prescribed to alleviate RA symptoms, may increase the requirement for some nutrients and reduce their absorption. This paper reviews the scientific evidence for the role of diet and nutrient supplementation in the management of RA, by alleviating symptoms, decreasing progression of the disease or by reducing the reliance on, or combating the side-effects of, NSAIDs. Supplementation with long-chain n-3 polyunsaturated fatty acids (PUFA) consistently demonstrates an improvement in symptoms and a reduction in NSAID usage. Evidence relating to other fatty acids, antioxidants, zinc, iron, folate, other B vitamins, calcium, vitamin D and fluoride are also considered. The present evidence suggests that RA patients should consume a balanced diet rich in long-chain n-3 PUFA and antioxidants. More randomized long-term studies are needed to provide evidence for the benefits of specific nutritional supplementation and to determine optimum intake, particularly for n-3 PUFA and antioxidants.

Could n-3 polyunsaturated fatty acids reduce pathological pain by direct actions on the nervous system?

The intake of n-3 polyunsaturated fatty acids (PUFAs) in many industrialized countries is relatively low and its increased consumption has protective and modifying effects on such diverse conditions as atherosclerosis, ventricular arrhythmias, multiple sclerosis, major depression and inflammatory and autoimmune diseases. In addition, n-3 PUFAs have been shown to alleviate pain in patients with rheumatoid arthritis, inflammatory bowel disease and in a number of other painful conditions. This has been attributed to the inhibition of pro-inflammatory eicosanoid and cytokine production by peripheral tissues. n-3 PUFAs have also been shown to inhibit eicosanoid production in glial cells, block voltage-gated sodium channels (VGSCs), inhibit neuronal protein kinases and modulate gene expression. They also appear to have mood-stabilizing and sympatholytic effects. The present article explores the possibility that, based on what is known about their neural and non-neural effects, n-3 PUFAs directly attenuate the neuronal and glial processes that underlie neuropathic and inflammatory pain.

Pilot study of dietary fatty acid supplementation in the treatment of adult periodontitis

The anti-inflammatory effects of both n-3 and n-6 polyunsaturated fatty acids (PUFA) have been demonstrated in vitro and in many disease states, in particular in the treatment of rheumatoid arthritis. The benefit of n-3 PUFA supplementation has been documented in animal models of periodontal inflammation and a trend towards reduced inflammation has been seen in human experimental gingivitis. The purpose of this study was to examine the potential anti-inflammatory effects of PUFA supplementation, by administration of fish oil as a source of the n-3 PUFA, eicosapentaenoic acid, and borage oil as a source of the n-6 PUFA, gamma-linolenic acid (GLA), to adults with periodontitis. Thirty adult human subjects with periodontitis were administered either fish oil 3000 mg daily; borage oil 3000 mg daily; fish oil 1500 and borage oil 1500 mg daily, or placebo. The modified gingival index, the plaque index (PI), periodontal probing depths and beta-glucuronidase levels in gingival crevicular fluid were measured at baseline and after 12 weeks of treatment. Improvement in gingival inflammation was observed in subjects treated with borage oil (P<0.016), with a trend apparent in subjects treated with fish oil or a combination of PUFA. There was no statistically significant improvement in PI, although a trend was apparent in those receiving borage oil. Improvement in probing depth was seen in those subjects treated with either fish oil alone or borage oil alone, but statistical significance was only seen for the comparison of borage oil and placebo (P<0.044). No change was seen in gingival crevicular fluid (GCF) beta-glucuronidase levels. The use of borage oil supplementation, a source of the n-6 PUFA, GLA, can have beneficial effects on periodontal inflammation. n-6 PUFA supplementation seemed to offer more impressive results than either n-3 PUFA supplementation or the combination of lower doses of the two supplements. Additional studies will be necessary to more fully assess the potential of these agents to favorably affect periodontal inflammation.

The Zone Diet phenomenon: a closer look at the science behind the claims

The purported health benefits of low-carbohydrate diets have been advocated intermittently over the last century and have enjoyed increasing popularity over the last decade. Although most revolve around the emphatic theme that carbohydrates are to blame for many chronic diseases, their specific ideologies are more variable and in some cases quite sophisticated. The Zone Diet phenomenon represents a new generation of modern low carbohydrate food fad with sales placing it among the most popular diet books in recent history. The Zone is a 40% carbohydrate, 30% protein and 30% fat eating plan that advocates only sparing use of grains and starches. The precise 0.75 protein to carbohydrate ratio required with each meal is promoted to reduce the insulin to glucagon ratio, which purportedly affects eicosanoid metabolism and ultimately produces a cascade of biological events leading to a reduction in chronic disease risk, enhanced immunity, maximal physical and mental performance, increased longevity and permanent weight loss. There is presently little scientific support for the connections made between diet, endocrinology and eicosanoid metabolism. In fact, a review of the literature suggests that there are scientific contradictions in the Zone Diet hypothesis that cast unquestionable doubt on its potential efficacy. The purpose of this review is to evaluate the scientific merit of the Zone Diet and its health claims in an effort to help delineate what is and what is not sound nutrition science.

(n-3) Polyunsaturated fatty acids promote activation-induced cell death in murine T lymphocytes

Previous studies showing dietary (n-3) polyunsaturated fatty acids (PUFA) attenuate T cell immune-mediated inflammatory diseases led us to hypothesize that (n-3) PUFA promote activation-induced cell death (AICD) in T cells. Because T cell subsets display a differential resistance to AICD, we compared the effects of (n-3) PUFA feeding on T cells stimulated in vitro to express different cytokine profiles. Mice were fed either diets lacking (n-3) PUFA (control) or (n-3) PUFA-containing diets for 14 d. Splenic T cells were stimulated with alphaCD3/alphaCD28, phorbol myristate acetate (PMA)/Ionomycin or alphaCD3/PMA for 48 h, followed by reactivation with the same stimuli for 5 h. Apoptosis was measured using Annexin V/propidium iodide. (n-3) PUFA were selectively incorporated into membrane phospholipid pools. Cytokine analyses revealed that (n-3) PUFA enhanced AICD only in T cells expressing a T helper cell (Th)1-like cytokine profile after stimulation with PMA/Ionomycin compared to mice fed the (n-6) PUFA control diet (P = 0.0008). In contrast, no increase in apoptosis was seen in T cells stimulated with alphaCD3/PMA, which exhibited a Th2 cytokine profile. These data demonstrate that the ability of (n-3) PUFA to promote AICD is dependent on the activation stimulus. In conclusion, we have identified a novel mechanism by which (n-3) PUFA modulate T cell-mediated immunity by selective deletion of Th1-like cells while maintaining or enhancing the Th2-mediated humoral immune response.

Synthesis of cetyl myristoleate and evaluation of its therapeutic efficacy in a murine model of collagen-induced arthritis

Cetyl myristoleate (CM) was reported by Diehl and May [J Pharm Sci 83 (1994) 296] to block inflammation and prevent adjuvant-induced arthritis in rats. To verify this earlier work, we have synthesized pure CM and tested its anti-arthritic properties in a collagen-induced arthritis model in DBA/1LacJ mice. Multiple intraperitoneal injections of CM in 450 and 900 mg kg(-1) doses resulted in a significantly lower incidence of disease and caused a modest but significant diminution in clinical signs in those mice that developed arthritis. CM administered in daily oral doses of 20 mg kg(-1) also reduced the incidence of arthritis and caused a small reduction in the clinical signs in mice that developed arthritis. Although the protective effect of CM in collagen-induced arthritis observed in the present study was less dramatic than that reported earlier, our results confirm the anti-arthritic properties of pure CM.

Gene polymorphisms, inflammatory diseases and cancer

Genes whose products play a critical role in regulation of the immune response include the human leucocyte antigen (HLA) and cytokine families of genes. The HLA genes are the most polymorphic found in the human genome, and the bulk of this polymorphism results in functional differences in expressed HLA molecules, resulting in inter-individual differences in presentation of peptide antigens to T-cells. In addition, a considerable number of cytokine-associated gene polymorphisms have been identified, the bulk of which occur in the upstream promoter sequences of these genes, which in many cases results in differential in vitro expression of the respective pro- or anti-inflammatory gene product. Particular HLA polymorphisms result in well-defined associations with a large number of immunologically-mediated diseases, including some diseases with known dietary risk factors. For example, individuals of HLA-DQA1*0501, DQB1*0201 genotype have a greater than 200-fold increased risk of developing intolerance to dietary wheat gluten (coeliac disease), and additional HLA-related factors may influence the development of malignant lymphoma within pre-existing coeliac disease. Similarly, HLA-DRB1 alleles sharing a common sequence motif constitute the primary known genetic risk factor for rheumatoid arthritis. The influence of polymorphisms associated with differential cytokine expression on disease susceptibility is currently of much interest. Most attention has been focused on associations with susceptibility to benign immunologically-mediated diseases, including a number of gut diseases. However, recent work from our laboratory indicates that cytokine polymorphisms may influence susceptibility to and prognosis in a number of different cancers, including malignant melanoma skin cancer and solid tumours which may be influenced by diet, such as prostate cancer (collaboration with the CRC/BPG UK Familial Prostate Cancer study). In addition, preliminary work suggests that dietary modulation of expression levels of certain cytokines in healthy human subjects may be genotype dependent.

15d-PGJ(2) is acting as a 'dual agent' on the regulation of COX-2 expression in human osteoarthritic chondrocytes

The PGD(2) metabolite 15-deoxy-delta12,14 PGJ(2) (15d-PGJ(2)), a potent peroxisome proliferator-activated receptor gamma (PPARgamma) activator, has recently received attention for its potential antiinflammatory effects, but its effect on the cyclooxygenase-2 (COX-2) production is still under debate. We investigated the effect of 15d-PGJ(2) on COX-2 and prostaglandin E(2) (PGE(2)) production in the absence or the presence of interleukin-1beta (IL-1beta) in human osteoarthritic chondrocytes.Data showed that, as expected, IL-1beta induced both COX-2 and PGE(2) production. The addition of 15d-PGJ(2) completely blocked (by 93%) the IL-1beta-induced PGE(2) synthesis, whereas COX-2 level was only partially reduced (by 72%). Interestingly in the absence of any COX-2 inducer, 15d-PGJ(2) up-regulated COX-2 expression without concomitant elevation of PGE(2) synthesis. This study showed that the PPARgamma agonist, 15d-PGJ(2), exerts a dual effect on COX-2 production. The mechanisms by which 15d-PGJ(2) favors COX-2 production will be discussed.

Dietary flax oil reduces renal injury, oxidized LDL content, and tissue n-6/n-3 FA ratio in experimental polycystic kidney disease

As whole flaxseed is beneficial in the treatment of experimental renal disease, we undertook a study to determine whether previously documented benefits of whole flaxseed could be reproduced with dietary low-lignan flax oil (FO), a rich source of alpha-linolenic acid, in experimental polycystic kidney disease. Male offspring of Han:SPRD-cy heterozygous rats were fed a synthetic diet containing FO or corn oil (CO) for 8 wk from the time of weaning. Renal inflammation, fibrosis, proliferation, cystic change, and oxidized-LDL were assessed morphometrically. Hepatic and renal lipid composition was assessed using GC. FO feeding produced hepatic and renal enrichment of n-3 PUFA and an increase in C18:>C18 PUFA ratios (18-carbon PUFA compared to longer-chain PUFA), with a reduction in proportion of hepatic long-chain PUFA. The FO-based diet was associated with lower mean cystic change by 29.7% (P = 0.018), fibrosis by 21.7% (P = 0.017), macrophage infiltration by 31.5% (P < 0.0001), epithelial proliferation by 18.7% (P = 0.0035), and ox-LDL detection by 31.4% (P < 0.0001) in Han:SPRD-cy heterozygotes. Serum creatinine was significantly lower in FO-fed diseased animals. A small hypocholesterolemic effect was noted in all animals fed FO. FO feeding moderates renal injury, modifies the profile of substrates available for elongation to eicosanoid precursors, and inhibits the elongation of C18 PUFA in this model. The consumption of FO-based products may prove a more practical way of obtaining health benefit than attempts to increase dietary content of unrefined seed.

Polyunsaturated fatty acids and inflammatory diseases

Inflammation is overall a protective response, whose main goal is to liberate the human being of cellular lesions caused by micro-organisms, toxins, allergens, etc., as well as its consequences, and of death cells and necrotic tissues. Chronic inflammation, which is detrimental to tissues, is the basic pathogenic mechanism of hypersensitivity reactions against xenobiotics. Other frequent pathologies, for instance atherosclerosis, chronic hepatitis, inflammatory bowel disease (IBD), liver cirrhosis, lung fibrosis, psoriasis, and rheumatoid arthritis are also chronic inflammatory diseases. Chemical mediators of inflammation are derived from blood plasma or different cell-type activity. Biogenic amines, eicosanoids and cytokines are within the most important mediators of inflammatory processes. The different activities of eicosanoids derived from arachidonic acid (20:4 n-6) versus those derived from eicosapentaenoic acid (20:5 n-3) are one of the most important mechanisms to explain why n-3, or omega-3, polyunsaturated fatty acids (PUFA) exhibit anti-inflammatory properties in many inflammatory diseases. Dietary supplements ranging 1-8 g per day of n-3 PUFA have been reportedly beneficial in the treatment of IBD, eczema, psoriasis and rheumatoid arthritis. In addition, recent experimental studies in rats with experimental ulcerative colitis, induced by intrarectal injection of trinitrobenzene sulphonic acid, have documented that treatment with n-3 long-chain PUFA reduces mucosal damage as assessed by biochemical and histological markers of inflammation. Moreover, the defence antioxidant system in this model is enhanced in treated animals, provided that the n-3 PUFA supply is adequately preserved from oxidation.

The modulatory effects of prostaglandin-E on cytokine production by human peripheral blood mononuclear cells are independent of the prostaglandin subtype

The production of inflammatory mediators, relevant to (auto)immune diseases and chronic inflammatory conditions, can be modulated by dietary intake of n-3 and n-6 long chain polyunsaturated fatty acids (PUFAs). It was suggested that these effects are related to the formation of different series of eicosanoids, in particular prostaglandin-E (PGE). In this study we investigated whether prostaglandin subtypes metabolized from arachidonic acid (PGE2), dihomo-gamma-linolenic acid (PGE1) or eicosapentaenoic acid (PGE3) have different effects on T-cell proliferation and cytokine production in vitro. Freshly isolated human peripheral blood mononuclear cells (PBMC) were stimulated with concanavalin A (ConA) or lipopolysaccharide (LPS) in the presence or absence of exogenous PGE1, PGE2 or PGE3. We found that tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and to a lesser extent interleukin (IL)-10 production was inhibited by all PGE-subtypes in ConA-stimulated PBMC concomitant with unaffected IL-2 levels. The modulated cytokine production of ConA stimulated cells was independent of T-cell proliferation. PGE2 and PGE1 moderately stimulated proliferation, while PGE3 inhibited the proliferative response to some extent. In LPS-stimulated PBMC, TNF-alpha production was inhibited by all PGE-subtypes, whereas IL-6 remained unaffected and IL-10 production was increased. Time course experiments on the effects of PGE-subtypes on cytokine production after ConA or LPS stimulation showed these effects to be time dependent, but indifferent of the prostaglandin subtype added. Overall, the modulatory effects of PGE on cytokine production were irrespective of the subtype. This may implicate that the immunomodulatory effects of PUFAs, with respect to cytokine production, are not caused by a shift in the subtype of PGE.