Polyunsaturated fatty acids, inflammatory processes and inflammatory bowel diseases

Neuroprotective effects of lipoxin A4 in central nervous system pathologies

Many diseases of the central nervous system are characterized and sometimes worsened by an intense inflammatory response in the affected tissue. It is now accepted that resolution of inflammation is an active process mediated by a group of mediators that can act in synchrony to switch the phenotype of cells, from a proinflammatory one to another that favors the return to homeostasis. This new genus of proresolving mediators includes resolvins, protectins, maresins, and lipoxins, the first to be discovered. In this short review we provide an overview of current knowledge into the cellular and molecular interactions of lipoxins in diseases of the central nervous system in which they appear to facilitate the resolution of inflammation, thus exerting a neuroprotective action.

Oleic acid promotes adaptability against oxidative stress in 3T3-L1 cells through lipohormesis

Although fatty acids are important components of biological membranes, energy sources, and signal transducers or precursors of lipid mediators, excess intake of fatty acids and their accumulation cause obesity and metabolic syndrome. Thus, fatty acid quantity is known to be an important factor for obesity-related diseases, but the effects of different types of fatty acids (i.e., fatty acid quality) on human health are not completely understood. We here focused on the relationship between fatty acid quality and oxidative stress by investigating whether resistibility to tert-butyl hydrperoxide (t-BuOOH)-induced oxidative stress in 3T3-L1 cells varied according to the fatty acid type. Among eight fatty acids (both saturated and unsaturated) tested, oleic acid (OA) exerted the most pronounced cytoprotective effects, with efficacy over a wide range of concentrations. OA treatment markedly enhanced the intracellular levels of lipid peroxidation markers, including N(ε)-(hexanoyl)lysine, 4-hydroxy-2-nonenal, and acrolein. The levels of these markers in OA-treated cells were decreased after t-BuOOH exposure, whereas the levels in untreated control cells were notably increased after t-BuOOH exposure. Our results suggested that unsaturated fatty acids, particularly OA, could promote an adaptive response and enhance cell tolerance through increased cellular antioxidative capacity via OA-induced mild lipid peroxidation (lipohormesis), and thus protect cells against subsequent oxidative stress-related injury.

Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance

Inflammation is a condition which contributes to a range of human diseases. It involves a multitude of cell types, chemical mediators, and interactions. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 (n-3) fatty acids found in oily fish and fish oil supplements. These fatty acids are able to partly inhibit a number of aspects of inflammation including leukocyte chemotaxis, adhesion molecule expression and leukocyte-endothelial adhesive interactions, production of eicosanoids like prostaglandins and leukotrienes from the n-6 fatty acid arachidonic acid, production of inflammatory cytokines, and T-helper 1 lymphocyte reactivity. In addition, EPA gives rise to eicosanoids that often have lower biological potency than those produced from arachidonic acid and EPA and DHA give rise to anti-inflammatory and inflammation resolving mediators called resolvins, protectins and maresins. Mechanisms underlying the anti-inflammatory actions of marine n-3 fatty acids include altered cell membrane phospholipid fatty acid composition, disruption of lipid rafts, inhibition of activation of the pro-inflammatory transcription factor nuclear factor kappa B so reducing expression of inflammatory genes, activation of the anti-inflammatory transcription factor peroxisome proliferator activated receptor γ and binding to the G protein coupled receptor GPR120. These mechanisms are interlinked, although the full extent of this is not yet elucidated. Animal experiments demonstrate benefit from marine n-3 fatty acids in models of rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and asthma. Clinical trials of fish oil in RA demonstrate benefit, but clinical trials of fish oil in IBD and asthma are inconsistent with no overall clear evidence of efficacy. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

Nutrition in pelvic radiation disease and inflammatory bowel disease: similarities and differences

Due to the intestinal inflammation, tissue damage, and painful abdominal symptoms restricting dietary intake associated with both diseases, patients with intestinal pelvic radiation disease (PRD) or inflammatory bowel disease (IBD) are at increased risk to develop protein calorie malnutrition and micronutrient deficiencies. In the current paper, we review the nutritional management of both diseases, listing the similar approaches of nutritional management and the nutritional implications of intestinal dysfunction of both diseases. Malnutrition is prevalent in patients with either disease and nutritional risk screening and assessment of nutritional status are required for designing the proper nutritional intervention plan. This plan may include dietary management, oral nutritional supplementation, and enteral and/or parenteral nutrition. In addition to managing malnutrition, nutrients exert immune modulating effects during periods of intestinal inflammation and can play a role in mitigating the risks associated with the disease activity. Consistently, exclusive enteral feeding is recommended for inducing remission in pediatric patients with active Crohn's disease, with less clear guidelines on use in patients with ulcerative colitis. The field of immune modulating nutrition is an evolving science that takes into consideration the specific mechanism of action of nutrients, nutrient-nutrient interaction, and preexisting nutritional status of the patients.

Effects of different ratios of ω-3/ω-6 polyunsaturated fatty acids on experimental acute colitis in rats

AIM: To investigate the effect of different ratios of ω-3/ω-6 of polyunsaturated fatty acids (PUFAs) on acute colitis induced with dextran sulfate sodium (DSS) in rats and explore the possible mechanisms.

METHODS: Thirty-two male SD rats were randomly divided into four groups (n = 8 for each): A (control), B (ω-3/ω-6, 1:1), C (ω-3/ω-6, 1:3) and D (ω-3/ω-6, 1:30). After six weeks of feeding with different diets, acute colitis in rats in groups B, C and D were induced by giving 3% DSS in drinking water for seven days. Then all the rats were sacrificed. Overall inflammatory severity score and histological damage score were calculated. The levels of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-a), nuclear transcription factor kappa B (NF-kB) in the colon, and the level of interleukin-6 (IL-6) in serum were measured by ELISA.

RESULTS: The overall inflammatory severity score in group B was significantly lower than those in groups C and D (2.8 ± 1.2 vs 4.3 ± 1.1, 5.6 ± 1.3, P < 0.05, P < 0.01). The histological damage score in group B was also significantly lower than those in groups C and D (3.2 ± 2.0 vs 35.0 ± 28.8, 27.0 ± 25.8, P < 0.01 for both). The levels of PGE2 and TNF-a in the colon were significantly lower in groups B and C than in group D [443.4 ± 67.3 (ng/100 g tissue), 419.5 ± 52.6 (ng/100 g tissue) vs 541.2 ± 68.5 (ng/100 g tissue), P < 0.05, P < 0.01; 189.2 ± 27.0 (ng/100 g tissue), 173.2 ± 50.2 (ng/100 g tissue) vs 270.3 ± 49.1 (ng/100 g tissue), P < 0.01 for both). The level of IL-6 in serum was significantly lower in group B than in groups C and D (97.1 ng/L ± 8.2 ng/L vs 129.1 ng/L ± 5.5 ng/L, 125.4 ng/L ± 19.6 ng/L, P < 0.01, P < 0.05). There were no statistical differences in the level of nuclear NF-kB between groups B, C and D [497.9 ± 50.7 (ng/100 g tissue), 569.1 ± 121.2 (ng/100 g tissue), 582.5 ± 123.1 (ng/100 g tissue)].

CONCLUSION: Higher ratios of ω-3/ω-6 PUFAs have a more significant protective effect against acute colitis, especially when the ratio is 1:1. The overall inflammatory severity score, histological damage score, the levels of PGE2 and TNF-a in colon and the level of IL-6 in serum are significantly lower in the 1:1 (ω-3/ω-6) group than in the 1:30 group. Adding moderate amount of ω-3 PUFA may be a new way to treat IBD.

Unsaturated fatty acids and insulin resistance in childhood obesity

OBJECTIVE

Obesity is characterized by increased levels of plasma free fatty acids (FFAs) that interfere with insulin signaling. The aim of our study was to assess the FFA profile in obese children and adolescents and to determine their relation with different degrees of insulin resistance.

METHODS

A transversal study was conducted of 51 children and adolescents (mean age, 11.7±1.6 years; 47% males) with obesity (body mass index ≥95 percentile). Anthropometric, clinical, and biochemical parameters were assessed. Insulin resistance was determined using the homeostasis model assessment of insulin resistance (HOMA-IR) index. Plasma fatty acids were quantified by high-performance liquid chromatography with heptadecanoic acid as the internal standard.

RESULTS

The mean concentration of myristic acid, linoleic acid, palmitic acid, oleic acid, stearic acid, and total fatty acids was 9.3±2.2, 86.5±38.3, 93.0±35.5, 177.0±83.6, 48.5±14.9, and 414.3±160.9 μmol/L, respectively. Total fatty acids and unsaturated fatty acids such as oleic acid and linoleic acid showed an inverse significant correlation with insulin resistance. Children with high insulin resistance (HOMA-IR >2.5) showed a decrease in unsaturated fatty acids compared with children having a HOMA-IR of <2.5. There were no changes in saturated fatty acid concentrations between those groups.

CONCLUSIONS

A decrease in unsaturated fatty acids was correlated with insulin resistance in childhood obesity.

Reprint of: A parallel randomized trial on the effect of a healthful diet on inflammageing and its consequences in European elderly people: design of the NU-AGE dietary intervention study

BACKGROUND

The proportion of European elderly is expected to increase to 30% in 2060. Combining dietary components may modulate many processes involved in ageing. So, it is likely that a healthful diet approach might have greater favourable impact on age-related decline than individual dietary components. This paper describes the design of a healthful diet intervention on inflammageing and its consequences in the elderly.

METHODS

The NU-AGE study is a parallel randomized one-year trial in 1250 apparently healthy, independently living European participants aged 65-80 years. Participants are randomised into either the diet group or control group. Participants in the diet group received dietary advice aimed at meeting the nutritional requirements of the ageing population. Special attention was paid to nutrients that may be inadequate or limiting in diets of elderly, such as vitamin D, vitamin B12, and calcium. C-reactive protein is measured as primary outcome.

DISCUSSION

The NU-AGE study is the first dietary intervention investigating the effect of a healthful diet providing targeted nutritional recommendations for optimal health and quality of life in apparently healthy European elderly. Results of this intervention will provide evidence on the effect of a healthful diet on the prevention of age related decline.

Altered colonic mucosal availability of n-3 and n-6 polyunsaturated fatty acids in ulcerative colitis and the relationship to disease activity

BACKGROUND AND AIMS

The polyunsaturated fatty acids (PUFA) arachidonic acid (AA, n-6) and eicosapentaenoic acid (EPA, n-3) are precursors of eicosanoids and other lipid mediators which have critical roles in inflammation. The mediators formed from the different PUFA have different potencies. We hypothesised that metabolic changes associated with colonic mucosal inflammation would modify the bioavailability of the eicosanoid precursors AA and EPA.

METHODS

Colonic mucosa biopsies were obtained from patients with ulcerative colitis and from matched controls. Inflammation was graded endoscopically and histologically. Esterified and non-esterified fatty acids were determined within the biopsies using gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, respectively.

RESULTS

Biopsy samples were collected from 69 UC patients (54 providing both inflamed and non-inflamed mucosa) and 69 controls. Inflamed mucosa had higher AA (p<0.001) and lower EPA (p<0.010) contents and a higher AA:EPA ratio (p<0.001). Inflamed mucosa also had higher docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) and lower linoleic acid (LA) and α-linolenic acid (α-LNA) contents (all p<0.001), compared to non-inflamed and controls. There were significant correlations between severity of inflammation and contents of AA, DPA and DHA (positive correlations) and of LA, α-LNA and EPA (negative correlations).

CONCLUSIONS

Higher AA, AA:EPA ratio, DPA and DHA and lower LA, α-LNA and EPA are seen in inflamed mucosa in UC and correlate with severity of inflammation. This suggests an alteration in fatty acid metabolism in the inflamed gut mucosa, which may offer novel targets for intervention and should be considered if nutritional strategies are used.

Increased FADS2-Derived n-6 PUFAs and Reduced n-3 PUFAs in Plasma of Atopic Dermatitis Patients

Fatty acid concentrations, in particular n-3 and n-6 polyunsaturated fatty acids (PUFAs), have been described to be dysregulated in atopic dermatitis (AD) patients. The role of genetic polymorphisms of fatty acid enzymes in AD is controversial. We determined in a Hungarian cohort of healthy volunteers (n = 20) and AD patients (n = 20) triglyceride-, sterol- and phospholipid-bound fatty acids in the plasma, mRNA expression of fatty acid desaturase 2 (FADS2) and stearoyl-coenzyme A desaturase 1 in peripheral blood mononuclear cells (PBMCs) and FADS2 concentrations in plasma. We observed higher levels of monounsaturated fatty acids, 16:1 versus 16:0 ratios in phospholipids, triglycerides and sterol esters in patients compared to healthy subjects. In addition higher levels of the FADS2-derived n-6 PUFAs &#947;-linolenic acid and dihomo-&#947;-linolenic acid were observed in PBMCs of patients as well as lower levels of n-3 PUFAs. We conclude that the increased expression of FADS2 in PBMCs, as a representative tissue accessible from human blood of AD patients, might be responsible for higher levels of FADS2-derived n-6 PUFAs and lower n-3 PUFA levels in patients.

Efficacy of omega-3 in treatment of recurrent aphthous stomatitis and improvement of quality of life: a randomized, double-blind, placebo-controlled study

OBJECTIVE

This study assessed the effects of systemic omega-3 on the treatment of recurrent aphthous stomatitis and on the improvement of quality of life.

STUDY DESIGN

Fifty participants were randomly assigned to receive either omega-3 (1 g, 3 times daily) or placebo for 6 months. Assessment of outcome measures including monthly number of new ulcers, average duration of ulcer episodes, and pain level of ulcers was carried out at baseline and monthly for 6 months. Analysis of potential impact on quality of life using the Oral Health Impact Profile 14 was carried out at baseline and 6 months.

RESULTS

Daily omega-3 treatment achieved a significant reduction in number of ulcers, duration of ulcers, and level of pain by 3 months that persisted for 6 months. Mean score on Oral Health Impact Profile 14 also significantly improved by 6 months.

CONCLUSIONS

A daily omega-3 regimen shows promise as therapy for treatment and management of patients with recurrent aphthous stomatitis.

A parallel randomized trial on the effect of a healthful diet on inflammageing and its consequences in European elderly people: design of the NU-AGE dietary intervention study

BACKGROUND

The proportion of European elderly is expected to increase to 30% in 2060. Combining dietary components may modulate many processes involved in ageing. So, it is likely that a healthful diet approach might have greater favourable impact on age-related decline than individual dietary components. This paper describes the design of a healthful diet intervention on inflammageing and its consequences in the elderly.

METHODS

The NU-AGE study is a parallel randomized one-year trial in 1250 apparently healthy, independently living European participants aged 65-80 years. Participants are randomised into either the diet group or control group. Participants in the diet group received dietary advice aimed at meeting the nutritional requirements of the ageing population. Special attention was paid to nutrients that may be inadequate or limiting in diets of elderly, such as vitamin D, vitamin B12, and calcium. C-reactive protein is measured as primary outcome.

DISCUSSION

The NU-AGE study is the first dietary intervention investigating the effect of a healthful diet providing targeted nutritional recommendations for optimal health and quality of life in apparently healthy European elderly. Results of this intervention will provide evidence on the effect of a healthful diet on the prevention of age related decline.

Fish oil alleviates activation of the hypothalamic-pituitary-adrenal axis associated with inhibition of TLR4 and NOD signaling pathways in weaned piglets after a lipopolysaccharide challenge

Long-chain n-3 (ω-3) polyunsaturated fatty acids exert beneficial effects in neuroendocrine dysfunctions in animal models and clinical trials. However, the mechanism(s) underlying the beneficial effects remains to be elucidated. We hypothesized that dietary treatment with fish oil (FO) could mitigate LPS-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis through inhibition of Toll-like receptor 4 and nucleotide-binding oligomerization domain protein signaling pathways. Twenty-four weaned pigs were used in a 2 × 2 factorial design, and the main factors consisted of diet (5% corn oil vs. 5% FO) and immunological challenge (saline vs. LPS). After 21 d of dietary treatment with 5% corn oil or FO diets, pigs were treated with saline or LPS. Blood samples were collected at 0 (preinjection), 2, and 4 h postinjection, and then pigs were humanely killed by intravenous injection of 40 mg/kg body weight sodium pentobarbital for tissue sample collection. FO led to enrichment of eicosapentaenoic acid and docosahexaenoic acid and total n-3 polyunsaturated fatty acids in hypothalamus, pituitary gland, adrenal gland, spleen, and thymus. FO decreased plasma adrenocorticotrophin and cortisol concentrations as well as mRNA expressions of hypothalamic corticotropin releasing hormone and pituitary proopiomelanocortin. FO also reduced mRNA expression of tumor necrosis factor-α in hypothalamus, adrenal gland, spleen, and thymus, and of cyclooxygenase 2 in hypothalamus. Moreover, FO downregulated the mRNA expressions of Toll-like receptor 4 (TLR4) and its downstream molecules, including cluster differentiation factor 14, myeloid differentiation factor 2, myeloid differentiation factor 88, interleukin-1 receptor-associated kinase 1, tumor necrosis factor-α receptor-associated factor 6, and nuclear factor kappa-light-chain-enhancer of activated B cells p65, and also decreased the mRNA expressions of nucleotide-binding oligomerization domain 1, nucleotide-binding oligomerization domain 2, and their adaptor molecule receptor-interacting serine/threonine-protein kinase 2. These results suggested that FO attenuates the activation of the HPA axis induced by LPS challenge. The beneficial effects of FO on the HPA axis may be associated with decreasing the production of brain or peripheral proinflammatory cytokines through inhibition of TLR4 and nucleotide-binding oligomerization domain protein signaling pathways.

Influence of dietary fat on intestinal microbes, inflammation, barrier function and metabolic outcomes

Recent studies using germ-free, gnotobiotic microbial transplantation/conventionalization or antibiotic treatment in rodent models have highlighted the critical role of intestinal microbes on gut health and metabolic functions of the host. Genetic and environmental factors influence the abundance and type of mutualistic vs. pathogenic bacteria, each of which has preferred substrates for growth and unique products of fermentation. Whereas some fermentation products or metabolites promote gut function and health, others impair gut function, leading to compromised nutrient digestion and barrier function that adversely impact the host. Such products may also influence food intake, energy harvest and expenditure, and insulin action, thereby influencing adiposity and related metabolic outcomes. Diet composition influences gut microbiota and subsequent fermentation products that impact the host, as demonstrated by prebiotic studies using oligosaccharides or other types of indigestible fiber. Recent studies also show that dietary lipids affect specific populations of gut microbes and their metabolic end products. This review will focus on studies examining the influence of dietary fat amount and type on the gut microbiome, intestinal health and positive and negative metabolic consequences. The protective role of omega-3-rich fatty acids on intestinal inflammation will also be examined.

The impact of meal composition on the release of fatty acids from salmon during in vitro gastrointestinal digestion

We hypothesize that the rate of release of lipids from salmon muscle during in vitro digestion is altered by additional meal components. In vitro digestion of salmon was performed using a mixture of porcine gastrointestinal enzymes and bile salts. Broccoli and barley were also added to the digestion simulating a meal. The extent of lipolysis was determined by measuring the release of fatty acids (FAs) during sampling at the simulated gastric phase endpoint (60 minutes) and 20, 40, 60, 80, 110 and 140 minutes simulated small intestinal phase, using solid phase extraction and GC-FID. Adding barley resulted in a lower overall release of FA from salmon, whereas broccoli caused an initial delay followed by increased release from 80-140 min when lipid digestion of salmon alone plateaued. The impact of broccoli and barley on the release of peptides and digesta viscosity were also measured. The effect of different components in the meal shown by this in vitro study suggests that it would be possible to make dietary changes affecting the lipolysis, further triggering specific responses in the gastrointestinal tract. However, these observations need to be validated in vivo, and the mechanisms need to be further examined.

Altered colonic mucosal Polyunsaturated Fatty Acid (PUFA) derived lipid mediators in ulcerative colitis: new insight into relationship with disease activity and pathophysiology

Objectives

Ulcerative colitis (UC) is a relapsing inflammatory disorder of unconfirmed aetiology, variable severity and clinical course, characterised by progressive histological inflammation and with elevation of eicosanoids which have a known pathophysiological role in inflammation. Therapeutic interventions targetting eicosanoids (5-aminosalicylates (ASA)) are effective first line and adjunctive treatments in mild-moderate UC for achieving and sustaining clinical remission. However, the variable clinical response to 5-ASA and frequent deterioration in response to cyclo-oxygenase (COX) inhibitors, has prompted an in depth simultaneous evaluation of multiple lipid mediators (including eicosanoids) within the inflammatory milieu in UC. We hypothesised that severity of inflammation is associated with alteration of lipid mediators, in relapsing UC.

Design

Study was case-control design. Mucosal lipid mediators were determined by LC-MS/MS lipidomics analysis on mucosal biopsies taken from patients attending outpatients with relapsing UC. Univariate and multivariate statistical analyses were used to investigate the association of mucosal lipid mediators, with the disease state and severity graded histologically.

Results

Levels of PGE₂, PGD₂, TXB₂, 5-HETE, 11-HETE, 12-HETE and 15-HETE are significantly elevated in inflamed mucosa and correlate with severity of inflammation, determined using validated histological scoring systems.

Conclusions

Our approach of capturing inflammatory mediator signature at different stages of UC by combining comprehensive lipidomics analysis and computational modelling could be used to classify and predict mild-moderate inflammation; however, predictive index is diminished in severe inflammation. This new technical approach could be developed to tailor drug treatments to patients with active UC, based on the mucosal lipid mediator profile.

Docosahexaenoic acid reduces inflammation and joint destruction in mice with collagen-induced arthritis

OBJECTIVE

This study was designed to determine the anti-inflammatory activity of docosahexaenoic acid (DHA), alone and in combination with eicosapentaenoic acid (EPA), in a murine model of rheumatoid arthritis, collagen induced arthritis (CIA).

METHODS

The CIA was induced in DBA/1OlaHsd mice by the injection of bovine type II collagen in Freunds's complete adjuvant on days 0 and 21. Mice were fed modified diets containing DHA and/or EPA for 4 weeks prior to the initial collagen injection until study termination at day 45. The severity of CIA was assessed by measuring erythema, edema and mobility of the digits on the fore and hind paws, as well as histology. The level of serum anti-collagen antibodies was determined by ELISA. The ex vivo effects of DHA and/or EPA on splenocyte proliferation and cytokine production were evaluated by BrdU method and ELISA.

RESULTS

Prophylactic treatment with DHA, and not DHA/EPA, significantly reduced arthritis severity and joint damage. Treatment with DHA also decreased anti-collagen (CII) antibodies in vivo, downregulated interleukin-1β, interferonγ and upregulated protective interleukin-10 ex vivo.

CONCLUSION

Prophylactic treatment with DHA was efficacious in a mouse model of rheumatoid arthritis and may be a useful intervention strategy against inflammatory arthritis.

Fish oil increases muscle protein mass and modulates Akt/FOXO, TLR4, and NOD signaling in weanling piglets after lipopolysaccharide challenge

Proinflammatory cytokines play a key role in the pathophysiology of muscle atrophy. In addition, n3 polyunsaturated fatty acids (PUFAs) exert an inhibitory effect on proinflammatory cytokines affecting many inflammatory diseases. We hypothesized that dietary supplementation of fish oil could attenuate lipopolysaccharide (LPS)-induced muscle atrophy. Weanling pigs were used in a 2 × 2 factorial design and the main factors included diet (5% corn oil or 5% fish oil) and immunological challenge (LPS or saline). After 21 d of treatment with either fish oil or corn oil, pigs received an i.p. injection of either saline or LPS. At 4 h postinjection, blood and muscle samples were obtained. Fish oil led to enrichment of eicosapentaenoic acid, docosahexaenoic acid, and total n3 PUFAs in muscles. Fish oil increased muscle protein mass, indicated by a higher protein:DNA ratio in gastrocnemius and longissimus dorsi (LD) muscles. In addition, fish oil increased Akt1 mRNA abundance and decreased Forkhead Box O (FOXO) 1 and FOXO4 mRNA abundance. Fish oil also increased phosphorylation of Akt and FOXO1 in gastrocnemius and LD muscles. Fish oil decreased the mRNA abundance of muscle atrophy F-box (MAFbx) and muscle RING finger 1 in gastrocnemius and LD muscles. Moreover, fish oil reduced the plasma tumor necrosis factor (TNF) α, muscle TNFα, and prostaglandin E2 concentrations, and muscle TNFα and cyclooxygenase 2 (COX2) mRNA abundance. Finally, fish oil downregulated the mRNA abundance of muscle toll-like receptor (TLR4) and its downstream signaling molecules [myeloid differentiation factor 88 (MyD88), TNFα receptor-associated factor 6 (TRAF6), and NF-κB p65], and nucleotide-binding oligomerization domain protein (NOD1), NOD2, and their adaptor molecule [receptor-interacting serine/threonine-protein kinase 2 (RIPK2)]. These results indicate fish oil may suppress muscle proinflammatory cytokine production via regulation of TLR and NOD signaling pathways and therefore improve muscle protein mass, possibly through maintenance of Akt/FOXO signaling.

Eicosapentaenoic and docosahexaenoic acid supplementation and inflammatory gene expression in the duodenum of obese patients with type 2 diabetes

Background

The extent to which long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) from fish oil such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) exert their anti-inflammatory effects by down-regulating intestinal inflammation in humans is unknown. We investigated the impact of LCn-3PUFA supplementation on inflammatory gene expression in the duodenum of obese patients with type 2 diabetes.

Findings

This placebo-controlled randomized crossover study included 12 men with type 2 diabetes. After a 4-week run-in period, patients received in a random sequence 5 g/d of fish oil (providing 3 g of EPA + DHA) and a placebo (corn and soybean oil) for 8 weeks each. The two treatment phases were separated by a 12-week washout period. Gene expression was assessed by real-time polymerase chain reaction in duodenal biopsy samples obtained in the fasted state at the end of each treatment phase. Intestinal mRNA expression levels of interleukin (IL)-6 and tumor-necrosis factor (TNF)-α were hardly detectable after either treatment (<100 copies/10⁵ copies of the reference gene ATP5o). Intestinal mRNA expression of IL-18 and of the transcription factor signal transducer and activator of transcription 3 (STAT3) was higher (>5000 copies/10⁵ copies ATP5o) but still relatively low. EPA + DHA supplementation had no impact on any of these levels (all P ≥ 0.73).

Conclusions

These data suggest that duodenal cells gene expression of pro-inflammatory cytokines is low in patients with type 2 diabetes and not affected by EPA + DHA supplementation. Further studies are warranted to determine if inflammatory gene expression in other tissues surrounding the intestine is modulated by EPA + DHA supplementation.

Trial registration

ClinicalTrials.gov ID: NCT01449773

Intake and serum profile of fatty acids are weakly correlated with global dietary quality in European adolescents

OBJECTIVE

The present study assessed whether compliance with the Food-Based Dietary Guidelines is related to habitual fatty acid (FA) intake and blood lipid parameters.

METHODS

Dietary information was collected by two non-consecutive 24-h recalls in 1804 European adolescents. Compliance with the Food-Based Dietary Guidelines was expressed by calculating the Diet Quality Index for Adolescents (DQI-A). Blood samples were collected in a randomly selected subset (n = 552). Relations between FA intake/serum concentrations and DQI-A were tested with multilevel regression analysis to correct for the study design (clustering within cities). Analyses were stratified for gender; age was entered as a covariate.

RESULTS

Better DQI-A scores were related to increased proportional intakes of energy from total fat, saturated FA, monounsaturated FA, and cholesterol (P < 0.001), whereas no significant association was observed with polyunsaturated FA intakes. In adolescents with higher compared with lower DQI-A scores, dairy products contributed more (21.0% versus 12.7%) and low-nutrient, energy-dense items contributed less (17.2% versus 26.3%) to the intake of total fat. A positive association was observed between the DQI-A scores and serum concentrations of eicosapentaenoic acid and docosahexaenoic acid (all P < 0.005). The latter, however, was significant only in girls. In boys, higher DQI-A scores were inversely associated with serum cholesterol concentrations (P < 0.05).

CONCLUSION

Although compliance with the Food-Based Dietary Guidelines was not always associated with a favorable FA intake pattern, a significant favorable association with some serum biomarkers was observed. This outcome underlines the importance of considering dietary habits instead of single-nutrient intakes.

FADS2 Genetic Variance in Combination with Fatty Acid Intake Might Alter Composition of the Fatty Acids in Brain

Multiple lines of evidence suggest that fatty acids (FA) play an important role in cognitive function. However, little is known about the functional genetic pathways involved in cognition. The main goals of this study were to replicate previously reported interaction effects between breast feeding (BF) and FA desaturase (FADS) genetic variation on IQ and to investigate the possible mechanisms by which these variants might moderate BF effect, focusing on brain expression. Using a sample of 534 twins, we observed a trend in the moderation of BF effects on IQ by FADS2 variation. In addition, we made use of publicly available gene expression databases from both humans (193) and mice (93) and showed that FADS2 variants also correlate with FADS1 brain expression (P-value<1.1E-03). Our results provide novel clues for the understanding of the genetic mechanisms regulating FA brain expression and improve the current knowledge of the FADS moderation effect on cognition.

High levels of anti-inflammatory and pro-resolving lipid mediators lipoxins and resolvins and declining docosahexaenoic acid levels in human milk during the first month of lactation

Background

The fatty acid mixture of human milk is ideal for the newborn but little is known about its composition in the first few weeks of lactation. Of special interest are the levels of long-chain PUFAs (LCPUFAs), since these are essential for the newborn’s development. Additionally, the LCPUFAs arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are precursors for lipid mediators which regulate inflammation.

Methods

We determined the composition of 94 human milk samples from 30 mothers over the first month of lactation for fatty acids using GC-MS and quantified lipid mediators using HPLC-MS/MS.

Results

Over the four weeks period, DHA levels decreased, while levels of γC18:3 and αC18:3 steadily increased. Intriguingly, we found high concentrations of lipid mediators and their hydroxy fatty acid precursors in human milk, including pro-inflammatory leukotriene B4 (LTB4) and anti-inflammatory and pro-resolving lipoxin A4 (LXA4), resolvin D1 (RvD1) and resolvin E1 (RvE1). Lipid mediator levels were stable with the exception of two direct precursors.

Conclusions

Elevated levels of DHA right after birth might represent higher requirements of the newborn and the high content of anti-inflammatory and pro-resolving lipid mediators and their precursors may indicate their role in neonatal immunity and may be one of the reasons for the advantage of human milk over infant formula.

Enhanced intestinal epithelial barrier health status on European sea bass (Dicentrarchus labrax) fed mannan oligosaccharides

The study assesses the effects of dietary mannan oligosaccharides (MOS) in European sea bass (Dicentrarchus labrax) posterior intestinal lipid class composition and its possible relation to the potential prostaglandins production and Gut Associated Lymphoid Tissue (GALT) stimulation. Fish were fed 4 g kg(-1) MOS (Bio-Mos(®) Aquagrade, Alltech, Inc., USA) for eight weeks. Fish fed MOS presented higher (P ≤ 0.05) weight gain, total length, and specific and relative growth rates than fish fed the control diet. Stimulated posterior gut of fish fed MOS showed higher (P ≤ 0.05) prostaglandins production than fish fed the control diet. Lipid class analyses of posterior gut revealed a reduction (P ≤ 0.05) in the neutral lipid fraction in fish fed MOS compared to fish fed the control diet, particularly due to a reduction (P ≤ 0.05) in triacylglycerols content. The polar lipid fraction increased (P ≤ 0.05) in fish fed MOS compared to fish fed the control diet, mainly due to an increase (P ≤ 0.05) in phosphatidylethanolamine and phosphatidylcoline contents. Light microscopy of posterior gut revealed increased number or goblet cells as well as higher level of infiltrated eosinophilic granulocytes for fish fed MOS. Transmission electron microscopy qualitative observations revealed a better preserved cytoarchitecture of the intestinal epithelial barrier in the posterior gut of fish fed MOS. Posterior gut of fish fed MOS presented more densely packed non-damaged enterocytes, better preserved tight junctions structure, healthier and more organized microvilli, and a higher presence of infiltrated lymphocytes and granulocytes compared fish fed the control diet. The present study indicates that dietary MOS enhances European sea bass posterior gut epithelial defense by increasing membrane polar lipids content in relation to a stimulation of the eicosanoid cascade and GALT, promoting posterior gut health status.

Omega-3 fatty acid for the treatment and remission of Crohn's disease

This integrative literature review focused on the use of omega-3 fatty acid supplementation for the treatment of Crohn's disease (CD). A systematic review of studies investigating the use of omega-3 in individuals with CD was performed. OVID MEDLINE, the Cochrane Database, and CINAHL were searched for pertinent research. Experiments were limited to double-blind placebo controlled trials. Five studies observing CD relapse rates and three studies examining biochemical changes were evaluated. The studies reviewed show contradicting information regarding the efficacy of omega-3 for CD. While some studies have shown supplementation with omega-3 results in sustained remission from disease, other studies concluded no correlation between omega-3 supplementation and improved remission rates. Studies investigating biochemical variables suggest favorable changes in immunological milieu, including modifications of lipid profiles and cytokine production. The studies reviewed are adversely limited by low number of participants, short duration of study and other significant deficits. Limited data remain available and current literature indicated mixed conclusions regarding the efficacy of omega-3 for treatment of CD. Further large-scale studies of longer duration are necessary.

The ω3-polyunsaturated fatty acid derivatives AVX001 and AVX002 directly inhibit cytosolic phospholipase A(2) and suppress PGE(2) formation in mesangial cells

BACKGROUND AND PURPOSE

ω3-polyunsaturated fatty acids (ω3-PUFAs) are known to exert anti-inflammatory effects in various disease models although their direct targets are only poorly characterized.

EXPERIMENTAL APPROACH

Here we report on two new cPLA(2) inhibitors, the ω3-derivatives AVX001 and AVX002, and their effects on inflammatory PGE(2) production in cultures of renal mesangial cells.

KEY RESULTS

AVX001 and AVX002 dose-dependently inhibited the group IVA cytosolic phospholipase A(2) (cPLA(2) ) in an in vitro activity assay with similar IC(50) values for AVX001 and AVX002, whereas the known cPLA(2) inhibitor AACOCF(3) was less potent and docosahexaenoic acid (DHA) was inactive. In renal mesangial cells, AVX001 and AVX002 suppressed IL-1β-induced PGE(2) synthesis. Mechanistically, this effect occurred by a down-regulation of IL-1β-induced group IIA-sPLA(2) protein expression, mRNA expression and promoter activity. A similar but less potent effect was seen with AACOCF(3) and no effect was seen with DHA. As gene expression of sPLA(2) is known to be regulated by the transcription factor NF-κB, we further investigated NF-κB activation. Both compounds prevented NF-κB activation by blocking degradation of the inhibitor of κB.

CONCLUSIONS AND IMPLICATIONS

These data show for the first time that the novel cPLA(2) inhibitors AVX001 and AVX002 exert an anti-inflammatory effect in cultures of renal mesangial cells and reduce the pro-inflammatory mediator PGE(2) through an inhibitory effect on NF-κB activation. Therefore, these compounds may represent promising novel drugs for the treatment of inflammatory disorders.

Effect of eicosapentaenoic acid-derived prostaglandin E3 on intestinal epithelial barrier function

Prostaglandins (PG) are inflammatory mediators derived from arachidonic or eicosapentaenoic acid giving rise to the 2-series or the 3-series prostanoids, respectively. Previously, we have observed that PGE2 disrupts epithelial barrier function. Considering the beneficial effect of fish oil consumption in intestinal inflammatory processes, the aim of this study was to assess the role of PGE3 on epithelial barrier function assessed from transepithelial electrical resistance and dextran fluxes in Caco-2 cells. The results indicate that PGE3 increased paracellular permeability (PP) to the same extent as PGE2, through the interaction with EP1 and EP4 receptors and with intracellular Ca(2+) and cAMP as the downstream targets. Moreover, we observed a redistribution of tight junction proteins, occludin and claudin-4. In conclusion, PGE3 is able to increase PP thus leading to reconsider the role of PGE2/PGE3 ratio in the beneficial effects of dietary fish oil supplementation in the disruption of barrier function.

Fungal arachidonic acid-rich oil: research, development and industrialization

Fungal arachidonic acid (ARA)-rich oil is an important microbial oil that affects diverse physiological processes that impact normal health and chronic disease. In this article, the historic developments and technological achievements in fungal ARA-rich oil production in the past several years are reviewed. The biochemistry of ARA, ARA-rich oil synthesis and the accumulation mechanism are first introduced. Subsequently, the fermentation and downstream technologies are summarized. Furthermore, progress in the industrial production of ARA-rich oil is discussed. Finally, guidelines for future studies of fungal ARA-rich oil production are proposed in light of the current progress, challenges and trends in the field.

Emerging drugs for the treatment of dry eye disease

INTRODUCTION

Dry eye disease (DED) is a common, age-related ocular condition that in its mildest forms causes bothersome symptoms of ocular discomfort, fatigue, and visual disturbance that interfere with quality of life and in its more severe forms causes chronic pain and fluctuating vision. Though it is highly prevalent and costs billions of dollars to manage, current treatments have largely been inadequate, making it a frustrating condition, both for physicians and patients alike.

AREAS COVERED

This article will cover the recently discovered pathophysiology of DED that has prompted investigators to explore new molecules that target the core mechanisms that drive DED. These include anti-inflammatory/immune-modulatory drugs, secretagogues, lubricant, hormones, and autologous serum. Their potential mechanism of action and data from recent trials on efficacy/safety will be reviewed.

EXPERT OPINION

The emerging drugs have a vast range of putative mechanisms of action that may not only provide symptomatic relief but may potentially break the vicious cycle of DED and provide long-lasting cure. Current and future research may change our perspective on DED and redefine its treatment algorithms.

Alternative sources of omega-3 fats: can we find a sustainable substitute for fish?

Increasing demand for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) containing fish oils is putting pressure on fish species and numbers. Fisheries provide fish for human consumption, supplement production and fish feeds and are currently supplying fish at a maximum historical rate, suggesting mass-scale fishing is no longer sustainable. However, the health properties of EPA and DHA long-chain (LC) omega-3 polyunsaturated fatty acids (PUFA) demonstrate the necessity for these oils in our diets. EPA and DHA from fish oils show favourable effects in inflammatory bowel disease, some cancers and cardiovascular complications. The high prevalence of these diseases worldwide indicates the requirement for alternative sources of LC-PUFA. Strategies have included plant-based fish diets, although this may compromise the health benefits associated with fish oils. Alternatively, stearidonic acid, the product of α-linolenic acid desaturation, may act as an EPA-enhancing fatty acid. Additionally, algae oils may be a promising omega-3 PUFA source for the future. Algae are beneficial for multiple industries, offering a source of biodiesel and livestock feeds. However, further research is required to develop efficient and sustainable LC-PUFA production from algae. This paper summarises the recent research for developing prospective substitutes for omega-3 PUFA and the current limitations that are faced.

A novel oral nutraceutical formula of omega-3 and omega-6 fatty acids with vitamins (PLP10) in relapsing remitting multiple sclerosis: a randomised, double-blind, placebo-controlled proof-of-concept clinical trial

OBJECTIVE

To assess whether three novel interventions, formulated based on a systems medicine therapeutic concept, reduced disease activity in patients with relapsing-remitting multiple sclerosis (MS) who were either treated or not with disease-modifying treatment.

DESIGN

A 30-month randomised, double-blind, placebo-controlled, parallel design, phase II proof-of-concept clinical study.

SETTINGS

Cyprus Institute of Neurology and Genetics.

PARTICIPANTS

80 participants were randomised into four groups of 20 each. A total of 41 (51%) patients completed the 30-month trial. The eligibility criteria were an age of 18-65; a diagnosis of relapsing-remitting MS according to the McDonald criteria; a score of 0.0-5.5 on the Expanded Disability Status Scale (EDSS); MRI showing lesions consistent with MS; at least one documented clinical relapse and either receiving or not a disease-modifying treatment within the 24-month period before enrolment in the study. Patients were excluded because of a recent (<30 days) relapse, prior immunosuppressant or monoclonal antibody therapy, pregnancy or nursing, other severe disease compromising organ function, progressive MS, history of recent drug or alcohol abuse, use of any additional food supplements, vitamins or any form of polyunsaturated fatty acids, and a history of severe allergic or anaphylactic reactions or known specific nutritional hypersensitivity.

INTERVENTIONS

The first intervention (A) was composed of Ω-3 and Ω-6 polyunsaturated fatty acids at 1:1 wt/wt. Specifically, the Ω-3 fatty acids were docosahexaenoic acid and eicosapentaenoic acid at 3:1 wt/wt, and the Ω-6 fatty acids were linoleic acid and γ-linolenic acid at 2:1 wt/wt. This intervention also included minor quantities of other specific polyunsaturated, monounsaturated and saturated fatty acids as well as vitamin A and vitamin E (α-tocopherol). The second intervention (B, PLP10) was a combination of A and γ-tocopherol. The third intervention (C) was γ-tocopherol alone. The fourth group of 20 participants received placebo. The interventions were administered per os (by mouth) once daily, 30 min before dinner for 30 months.

MAIN OUTCOME MEASURES

The primary end point was the annualised relapse rate (ARR) of the three interventions versus the placebo at 2 years. The secondary end point was the time to confirmed disability progression at 2 years.

RESULTS

A total of 41 (51%) patients completed the 30-month trial. Overall, for the per-protocol analysis of the 2-year primary end point, eight relapses were recorded in the PLP10 group (n=10; 0.40 ARR) versus 25 relapses in the placebo group (n=12; 1.04 ARR), representing a 64% adjusted relative rate reduction for the PLP10 group (RRR 0.36, 95% CI 0.15 to 0.87, p=0.024). In a subgroup analysis that excluded patients on monoclonal antibody (natalizumab) treatment, the observed adjusted RRR became stronger (72%) over the 2 years (RRR 0.28, 95% CI 0.10 to 0.79, p=0.016). The per-protocol analysis for the secondary outcome at 2 years, the time to disability progression, was significantly longer only for PLP10. The cumulative probability of disability progression at 2 years was 10% in the PLP10 group and 58% in the placebo group (unadjusted log-rank p=0.019). In a subgroup analysis that excluded patients on natalizumab, the cumulative probability of progression was 10% for the 10 patients in the PLP10 group and 70% for the 12 patients in the placebo group, representing a relative 86% decrease in the risk of the sustained progression of disability in the PLP10 group (unadjusted log-rank p=0.006; adjusted HR, 0.11; 95% CI 0.01 to 0.97, p=0.047). No adverse events were reported. Interventions A (10 patients) and C (9 patients) showed no significant efficacy.

CONCLUSIONS

In this small proof-of-concept, randomised, double-blind clinical trial; the PLP10 treatment significantly reduced the ARR and the risk of sustained disability progression without any reported serious adverse events. Larger studies are needed to further assess the safety and efficacy of PLP10.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial, number ISRCTN87818535.

Release of EPA and DHA from salmon oil – a comparison of in vitro digestion with human and porcine gastrointestinal enzymes

In the present study, we hypothesised whether in vitro digestion of salmon oil would release different amounts of PUFA depending on the origin of the lipolytic enzymes used. For this purpose, in vitro digestion of salmon oil (SO) was performed using human duodenal juice (HDJ) or a commercial enzyme preparation consisting of porcine pancreatin and bile (PB). The lipolytic effect was determined by measuring the release of fatty acids (FA) using solid-phase extraction and GC–flame ionisation detection, withdrawing samples every 20 min during digestion. The amount of FA released indicated that a plateau was reached after 80 min with approximately similar amounts of FA detected using both HDJ and PB (379 (sd 18) and 352 (sd 23) mg/g SO, respectively). However, the release of 18 : 2, EPA (20 : 5) and DHA (22 : 6) was significantly different during in vitro digestion. At 80 min, HDJ and PB released 43 and 33 % of 18 : 2, 14 and 9 % of EPA and 11 and 9 % of DHA, respectively. Both enzyme preparations released approximately the same amounts of the other FA analysed. The effect of the addition of bile salts (BS) was significantly different in the two enzyme systems, where porcine pancreatin highly responded to the increase in BS concentration, in contrast to HDJ.

Pharmaconutrition: acute fatty acid modulation of circulating cytokines in elderly patients in the ICU

BACKGROUND

Enteral supply of ω-3 polyunsaturated fatty acids has been used in an attempt to modulate inflammation and improve outcome in critically ill patients. However, enteral administration may be slow to change membrane composition and therefore may not be the best route to supply these fatty acids in patients with acute conditions. This study evaluated the effects of short-term intravenous (IV) administration of fish oil-based lipid emulsion (FLE) as pharmaconutrition on cytokine levels in critically ill elderly patients.

METHODS

Enterally fed patients (n = 40; aged 60-80 years) were recruited in the first 48 hours of intensive care unit (ICU) admission. Fifteen patients received IV FLE (0.2 g/kg body weight) over 6 hours for 3 consecutive days, and 25 patients did not receive IV lipid (control). Samples were collected before and 24 hours and 72 hours after the third FLE infusion. Nutrient intakes, clinical parameters, and serum cytokine concentrations were measured.

RESULTS

Compared with the control, FLE resulted in higher energy intake, lower serum tumor necrosis factor-α and interleukin (IL)-8 concentrations, and higher serum IL-10. These differences occurred around 7-9 days of ICU stay at the time of the patient's extubation. ICU stay, mortality, and markers of coagulation and liver function did not differ between groups.

CONCLUSIONS

Short-term IV FLE modulates some inflammatory markers in critically ill elderly patients receiving enteral nutrition (EN), suggesting an anti-inflammatory effect. This may be a benefit and suggests a role for FLE administration as a supplement in elderly ICU patients receiving standard EN.

Metabolic signatures of extreme longevity in northern Italian centenarians reveal a complex remodeling of lipids, amino acids, and gut microbiota metabolism

The aging phenotype in humans has been thoroughly studied but a detailed metabolic profiling capable of shading light on the underpinning biological processes of longevity is still missing. Here using a combined metabonomics approach compromising holistic (1)H-NMR profiling and targeted MS approaches, we report for the first time the metabolic phenotype of longevity in a well characterized human aging cohort compromising mostly female centenarians, elderly, and young individuals. With increasing age, targeted MS profiling of blood serum displayed a marked decrease in tryptophan concentration, while an unique alteration of specific glycerophospholipids and sphingolipids are seen in the longevity phenotype. We hypothesized that the overall lipidome changes specific to longevity putatively reflect centenarians' unique capacity to adapt/respond to the accumulating oxidative and chronic inflammatory conditions characteristic of their extreme aging phenotype. Our data in centenarians support promotion of cellular detoxification mechanisms through specific modulation of the arachidonic acid metabolic cascade as we underpinned increased concentration of 8,9-EpETrE, suggesting enhanced cytochrome P450 (CYP) enzyme activity. Such effective mechanism might result in the activation of an anti-oxidative response, as displayed by decreased circulating levels of 9-HODE and 9-oxoODE, markers of lipid peroxidation and oxidative products of linoleic acid. Lastly, we also revealed that the longevity process deeply affects the structure and composition of the human gut microbiota as shown by the increased extrection of phenylacetylglutamine (PAG) and p-cresol sulfate (PCS) in urine of centenarians. Together, our novel approach in this representative Italian longevity cohort support the hypothesis that a complex remodeling of lipid, amino acid metabolism, and of gut microbiota functionality are key regulatory processes marking exceptional longevity in humans.

Metabolic signatures of extreme longevity in northern Italian centenarians reveal a complex remodeling of lipids, amino acids, and gut microbiota metabolism

The aging phenotype in humans has been thoroughly studied but a detailed metabolic profiling capable of shading light on the underpinning biological processes of longevity is still missing. Here using a combined metabonomics approach compromising holistic ¹H-NMR profiling and targeted MS approaches, we report for the first time the metabolic phenotype of longevity in a well characterized human aging cohort compromising mostly female centenarians, elderly, and young individuals. With increasing age, targeted MS profiling of blood serum displayed a marked decrease in tryptophan concentration, while an unique alteration of specific glycerophospholipids and sphingolipids are seen in the longevity phenotype. We hypothesized that the overall lipidome changes specific to longevity putatively reflect centenarians' unique capacity to adapt/respond to the accumulating oxidative and chronic inflammatory conditions characteristic of their extreme aging phenotype. Our data in centenarians support promotion of cellular detoxification mechanisms through specific modulation of the arachidonic acid metabolic cascade as we underpinned increased concentration of 8,9-EpETrE, suggesting enhanced cytochrome P450 (CYP) enzyme activity. Such effective mechanism might result in the activation of an anti-oxidative response, as displayed by decreased circulating levels of 9-HODE and 9-oxoODE, markers of lipid peroxidation and oxidative products of linoleic acid. Lastly, we also revealed that the longevity process deeply affects the structure and composition of the human gut microbiota as shown by the increased extrection of phenylacetylglutamine (PAG) and p-cresol sulfate (PCS) in urine of centenarians. Together, our novel approach in this representative Italian longevity cohort support the hypothesis that a complex remodeling of lipid, amino acid metabolism, and of gut microbiota functionality are key regulatory processes marking exceptional longevity in humans.

Omega-3 polyunsaturated fatty acids and inflammatory processes: nutrition or pharmacology?

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are n-3 fatty acids found in oily fish and fish oil supplements. These fatty acids are able to inhibit partly a number of aspects of inflammation including leucocyte chemotaxis, adhesion molecule expression and leucocyte-endothelial adhesive interactions, production of eicosanoids like prostaglandins and leukotrienes from the n-6 fatty acid arachidonic acid, production of inflammatory cytokines and T cell reactivity. In parallel, EPA gives rise to eicosanoids that often have lower biological potency than those produced from arachidonioc acid and EPA and DHA give rise to anti-inflammatory and inflammation resolving resolvins and protectins. Mechanisms underlying the anti-inflammatory actions of n-3 fatty acids include altered cell membrane phospholipid fatty acid composition, disruption of lipid rafts, inhibition of activation of the pro-inflammatory transcription factor nuclear factor kappa B so reducing expression of inflammatory genes, activation of the anti-inflammatory transcription factor NR1C3 (i.e. peroxisome proliferator activated receptor γ) and binding to the G protein coupled receptor GPR120. These mechanisms are interlinked. In adult humans, an EPA plus DHA intake greater than 2 g day⁻¹ seems to be required to elicit anti-inflammatory actions, but few dose finding studies have been performed. Animal models demonstrate benefit from n-3 fatty acids in rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and asthma. Clinical trials of fish oil in patients with RA demonstrate benefit supported by meta-analyses of the data. Clinical trails of fish oil in patients with IBD and asthma are inconsistent with no overall clear evidence of efficacy.

n-3 PUFA added to high-fat diets affect differently adiposity and inflammation when carried by phospholipids or triacylglycerols in mice

Background

Dietary intake of n-3 polyunsaturated fatty acids (PUFA) is primarily recognized to protect against cardiovascular diseases, cognitive dysfunctions and the onset of obesity and associated metabolic disorders. However, some of their properties such as bioavailability can depend on their chemical carriers. The objective of our study was to test the hypothesis that the nature of n-3 PUFA carrier results in different metabolic effects related to adiposity, oxidative stress and inflammation.

Methods

4 groups of C57BL/6 mice were fed for 8 weeks low fat (LF) diet or high-fat (HF, 20%) diets. Two groups of high-fat diets were supplemented with long-chain n-3 PUFA either incorporated in the form of phospholipids (HF-ω3PL) or triacylglycerols (HF-ω3TG).

Results

Both HF-ω3PL and HF-ω3TG diets reduced the plasma concentrations of (i) inflammatory markers such as monocyte chemoattractant protein-1 (MCP-1) and interleukin 6 (IL-6), (ii) leptin and (iii) 4-hydroxy-2-nonenal (4-HNE), a marker of n-6 PUFA-derived oxidative stress compared with the control HF diet. Moreover, in both HF-ω3PL and HF-ω3TG groups, MCP-1 and IL-6 gene expressions were decreased in epididymal adipose tissue and the mRNA level of gastrointestinal glutathione peroxidase GPx2, an antioxidant enzyme, was decreased in the jejunum compared with the control HF diet. The type of n-3 PUFA carrier affected other outcomes. The phospholipid form of n-3 PUFA increased the level of tocopherols in epididymal adipose tissue compared with HF-ω3TG and resulted in smaller adipocytes than the two others HF groups. Adipocytes in the HF-ω3PL and LF groups were similar in size distribution.

Conclusion

Supplementation of mice diet with long-chain n-3 PUFA during long-term consumption of high-fat diets had the same lowering effects on inflammation regardless of triacyglycerol or phospholipid carrier, whereas the location of these fatty acids on a PL carrier had a major effect on decreasing the size of adipocytes that was not observed with the triacyglycerol carrier. Altogether, these results would support the development functional foods containing LC n-3 PUFA in the form of PL in order to prevent some deleterious outcomes associated with the development of obesity.

Evaluation of suppressive and pro-resolving effects of EPA and DHA in human primary monocytes and T-helper cells

Despite their beneficial anti-inflammatory properties, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may increase the infection risk at high doses, likely by generating an immune-depressed state. To assess the contribution of different immune cell populations to the immunomodulatory fatty acid effect, we comparatively investigated several aspects of inflammation in human T-helper (Th) cells and monocytes. Both fatty acids, but DHA to a lesser extent compared with EPA, selectively and dose-dependently reduced the percentage of cytokine-expressing Th cells in a peroxisome proliferator-activated receptor (PPAR)γ-dependent fashion, whereas the expression of the cell surface marker CD69 was unaltered on activated T cells. In monocytes, both EPA and DHA increased interleukin (IL)-10 without affecting tumor necrosis factor (TNF)-α and IL-6. Cellular incorporation of EPA and DHA occurred mainly at the expense of arachidonic acid. Concomitantly, thromboxane B (TXB)2 and leukotriene B (LTB)4 in supernatants decreased, while levels of TXB3 and LTB5 increased. This increase was independent of activation and in accordance with cyclooxygenase expression patterns in monocytes. Moreover, EPA and DHA gave rise to a variety of mono- and trihydroxy derivatives of highly anti-inflammatory potential, such as resolvins and their precursors. Our results suggest that EPA and DHA do not generally affect immune cell functions in an inhibitory manner but rather promote pro-resolving responses.

Fish oil attenuates liver injury caused by LPS in weaned pigs associated with inhibition of TLR4 and nucleotide-binding oligomerization domain protein signaling pathways

This study evaluated whether fish oil exerted a hepatoprotective effect in a LPS-induced liver injury model via regulation of TLR4 and nucleotide-binding oligomerization domain protein (NOD) signaling pathways. Twenty-four piglets were used in a 2 × 2 factorial design, and the main factors included diet (5% corn oil or 5% fish oil) and immunological challenge (LPS or saline). Fish oil resulted in enrichment of eicosapentaenoic acid, docosahexaenoic acid and total (n-3) polyunsaturated fatty acids in liver. Less severe liver injury was observed in pigs fed fish oil, as evidenced by improved serum biochemical parameters and less severe histological liver damage. In addition, higher expression of liver tight junction proteins, and lower hepatocyte proliferation and higher hepatocyte apoptosis were observed in pigs fed fish oil. The improved liver integrity in pigs fed fish oil was concurrent with reduced hepatic mRNA expression of TLR4, myeloid differentiation factor 88, IL-1 receptor-associated kinase 1 and TNF- α receptor-associated factor 6, and NOD1, NOD2 and receptor-interacting serine/threonine-protein kinase 2, as well as reduced hepatic protein expression of NF-κB p65, leading to reduced hepatic pro-inflammatory mediators. These results indicate that fish oil improves liver integrity partially via inhibition of TLR4 and NOD signaling pathways under an inflammatory condition.

Dietary oils and FADS1-FADS2 genetic variants modulate [13C]α-linolenic acid metabolism and plasma fatty acid composition

BACKGROUND

Desaturation of dietary α-linolenic acid (ALA) to omega-3 (n-3) long-chain fatty acids (FAs) is mediated through FA desaturases (FADS1-FADS2) and may be influenced by dietary FA composition.

OBJECTIVE

We investigated the effects of diets enriched in flaxseed oil (FXCO) or high-oleic acid canola oil (HOCO) compared with a Western diet (WD) and FADS1-FADS2 single nucleotide polymorphisms (SNPs) on plasma FAs and [U-(13)C]ALA metabolism.

DESIGN

In a randomized crossover design, 36 hyperlipidemic subjects consumed 3 isoenergetic diets enriched in FXCO (20.6 g ALA/d), HOCO (2.4 g ALA/d), or WD (1.3 g ALA/d) for 4 wk. On day 27, blood was sampled 0, 24, and 48 h after the subjects (n = 26) consumed 45 mg [U-(13)C]ALA. The subjects were genotyped for 4 FADS SNPs.

RESULTS

FXCO increased (P < 0.001) plasma ALA, EPA, and docosapentaenoic acid (DPA), with no change in DHA compared with the HOCO or WD diets. At 24 and 48 h, [U-(13)C]ALA recovered as plasma [(13)C]EPA and [(13)C]DPA were lower (P < 0.001) after the FXCO diet than after the HOCO and WD diets. No change in [(13)C]DHA was observed between diets. Minor allele homozygotes of rs174545, rs174583, rs174561, and rs174537 had lower (P < 0.05) plasma EPA, arachidonic acid (AA), EPA/ALA, and AA/linoleic acid compositions and lower (P < 0.05) plasma [(13)C]EPA enrichment at 24 and 48 h in comparison with carriers of the major allele after all diets. SNPs were not associated with plasma composition of DHA or [(13)C]DHA enrichment.

CONCLUSION

An increase in ALA intake resulting in increased plasma EPA composition may be cardioprotective, especially in minor allele homozygotes. This trial was registered at www.clinicaltrials.gov as NCT00927199.

N-3 polyunsaturated fatty acids, body fat and inflammation

BACKGROUND

Based on animal studies, n-3 polyunsaturated fatty acids (PUFAs) have been suggested to lower the risk of obesity and inflammation. We aimed to investigate if, among humans, intake of n-3 PUFAs was associated with i) total body fat, ii) body fat distribution and iii) obesity-related inflammatory markers.

METHODS

The study population consisted of 1,212 healthy individuals with information on habitual food intake from food frequency questionnaires, six different measures of body fat, and levels of six circulating inflammatory markers. Multiple linear regression analysis of intakes of PUFAs in relation to outcomes were performed and adjusted for potential confounders.

RESULTS

Absolute n-3 PUFA intake, but not n-3/n-6, was inversely associated with the different measures of body fat. Among n-3 PUFA derivatives, only α-linolenic acid (ALA) was inversely associated with body fat measures. No significant interactions with the dietary macronutrient composition were observed. Pro-inflammatory cytokines were not associated with absolute PUFA intake, but the macrophage inflammatory protein-1α (MIP-1α) was associated with the n-3/n-6 ratio.

CONCLUSION

In humans, intake of n-3 PUFAs, in particular ALA, is beneficially associated with body fatness. The favourable association is, however, not reflected in systemic levels of pro-inflammatory cytokines, nor is it influenced by macronutrients in the diet.

Plasma cytokines and markers of endothelial activation increase after packed red blood cell transfusion in the preterm infant

BACKGROUND

Transfusion of packed red blood cells (PRBCs) saves lives in the neonatal critical care setting and is one of the most common interventions in the preterm infant. The number and volume of PRBC transfusions are associated with several major neonatal morbidities, although a direct causal link between transfusion and major neonatal morbidity is still to be proven. Transfusion-related immunomodulation (TRIM) may underlie these adverse outcomes, yet it has received little attention in the high-risk preterm infant.

METHODS

One transfusion event was studied in infants ≤28 wk gestation between 2 and 6 wk postnatal age (n = 28). Plasma inflammatory cytokines and markers of endothelial activation were measured in the infants before and 2-4 h after transfusion, as well as in the donor pack.

RESULTS

Median (range) age at transfusion was 18 (14-39) days with the pretransfusion hemoglobin level at 9.8 (7.4-10.2) g/dl. Interleukin (IL)-1β (P = 0.01), IL-8 (P = <0.001), tumor necrosis factor-α (P = 0.008), and monocyte chemoattractant protein (P = 0.01) were increased after transfusion. A similar elevation in markers of endothelial activation was seen after transfusion with increased plasma macrophage inhibitory factor (P = 0.005) and soluble intracellular adhesion molecule-1 (P = <0.001).

CONCLUSION

Production of inflammatory cytokines and immunoactivation of the endothelium observed after the transfusion of PRBCs in the preterm infant may be a manifestation of TRIM. The implications of this emerging phenomenon within the preterm neonatal population warrant further investigation.

Long-chain PUFA supplementation in rural African infants: a randomized controlled trial of effects on gut integrity, growth, and cognitive development

BACKGROUND

Intestinal damage and malabsorption caused by chronic environmental enteropathy are associated with growth faltering seen in infants in less-developed countries. Evidence has suggested that supplementary omega-3 (n-3) long-chain PUFAs (LC-PUFAs) might ameliorate this damage by reducing gastrointestinal inflammation. LC-PUFA supplementation may also benefit cognitive development.

OBJECTIVE

We tested whether early n-3 LC-PUFA supplementation improves infant intestinal integrity, growth, and cognitive function.

DESIGN

A randomized, double-blind, controlled trial [200 mg DHA and 300 mg EPA or 2 mL olive oil/d for 6 mo] was conducted in a population of 172 rural Gambian infants aged 3-9 mo. The primary endpoints were anthropometric measures and gut integrity [assessed by using urinary lactulose:mannitol ratios (LMRs)]. Plasma fatty acid status, intestinal mucosal inflammation (fecal calprotectin), daily morbidity, and cognitive development (2-step means-end test and an attention assessment) were secondary endpoints.

RESULTS

PUFA supplementation resulted in a significant increase in plasma n-3 LC-PUFA concentrations (P < 0.001 for both DHA and EPA) and midupper arm circumference (MUAC) (effect size: 0.31 z scores; 95% CI: 0.06, 0.56; P = 0.017) at 9 mo of age. At 12 mo, MUAC remained greater in the intervention group, and we observed significant increases in skinfold thicknesses (P ≤ 0.022 for all). No other significant differences between treatment groups were detected for growth or LMRs at 9 mo or for secondary outcomes.

CONCLUSIONS

Fish-oil supplementation successfully increased plasma n-3 fatty acid status. However, in young, breastfed Gambian infants, the intervention failed to improve linear growth, intestinal integrity, morbidity, or selected measures of cognitive development. The trial was registered at www.isrctn.org as ISRCTN66645725.

Production of TNF-α, nitric oxide and hydrogen peroxide by macrophages from mice with paracoccidioidomycosis that were fed a linseed oil-enriched diet

Omega-3 polyunsaturated fatty acids (n-3 PUFA) can modulate the immune system and their primary effect is on macrophage function. Paracoccidioidomycosis (PCM) is an endemic systemic mycosis in Latin America that is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). Macrophages are the main defence against this pathogen and have microbicidal activity that is dependent on interferon-Γ and tumour necrosis factor (TNF)-α. These cytokines stimulate the synthesis of nitric oxide (NO) and hydrogen peroxide (H₂O₂), leading to the death of the fungus. To study the effect of n-3 PUFA on the host immune response during experimental PCM, macrophages that were obtained from animals infected with Pb18 and fed a diet enriched by linseed (LIN) oil were cultured and challenged with the fungus in vitro. The macrophage function was analysed based on the concentrations of TNF-α, NO and H₂O₂. LIN oil seems to influence the production of TNF-α during the development of disease. A diet enriched with LIN oil influences the microbicidal activity of the macrophages by inducing the production of cytokines and metabolites such as NO and H₂O₂, predominantly in the chronic phase of infection.

Dietary conjugated linoleic acid activates PPARγ and the intestinal trefoil factor in SW480 cells and mice with dextran sulfate sodium-induced colitis

A central event in inflammatory bowel disease is the disruption of the mucosal homeostasis. Trefoil peptides [(TFF)] are emerging as key mediators in the defense and repair of the gastrointestinal mucosa. Here, we demonstrate induction of TFF by CLA with therapeutic antiinflammatory effects in a mouse model of inflammatory bowel disease. SW480 cells were treated with linoleic acid or CLA (0-2.5 μmol/L) in the absence or presence of the PPARγ inhibitor GW9662. Cells treated with CLA showed an upregulation of the intestinal trefoil factor, which was prevented by pretreatment with GW9662. Dextran sulfate sodium (2%) was used to induce colitis in mice and they were simultaneously fed with a standard or a CLA-supplemented (100 mg · kg(-1) · d(-1)) diet for 7 d. The CLA-enriched diet prevented the colon shortening induced by DSS and markedly reduced the disease activity index and the colonic expression of inducible NO synthase and NF-κB. Immunohistochemistry revealed an increase in PPARγ and TFF3 expression after CLA administration. Altogether, these results indicate that dietary CLA protects against DSS-induced colitis in a process involving induction of PPARγ and TFF3.

Metabolic response to Klebsiella pneumoniae infection in an experimental rat model

Bacteremia, the presence of viable bacteria in the blood stream, is often associated with several clinical conditions. Bacteremia can lead to multiple organ failure if managed incorrectly, which makes providing suitable nutritional support vital for reducing bacteremia-associated mortality. In order to provide such information, we investigated the metabolic consequences of a Klebsiella pneumoniae (K. pneumoniae) infection in vivo by employing a combination of (1)H nuclear magnetic resonance spectroscopy and multivariate data analysis. K. pneumoniae was intravenously infused in rats; urine and plasma samples were collected at different time intervals. We found that K. pneumoniae-induced bacteremia stimulated glycolysis and the tricarboxylic acid cycle and also promoted oxidation of fatty acids and creatine phosphate to facilitate the energy-demanding host response. In addition, K. pneumoniae bacteremia also induced anti-endotoxin, anti-inflammatory and anti-oxidization responses in the host. Furthermore, bacteremia could cause a disturbance in the gut microbiotal functions as suggested by alterations in a range of amines and bacteria-host co-metabolites. Our results suggest that supplementation with glucose and a high-fat and choline-rich diet could ameliorate the burdens associated with bacteremia. Our research provides underlying pathological processes of bacteremia and a better understanding of the clinical and biochemical manifestations of bacteremia.