Oxidised metabolites of the omega-6 fatty acid linoleic acid activate dFOXO.

Obesity-induced inflammation, or meta-inflammation, plays key roles in metabolic syndrome and is a significant risk factor in diabetes and cardiovascular disease. To investigate causal links between obesity, meta-inflammation, and insulin signaling we established a Drosophila model to determine how elevated dietary fat and changes in the levels and balance of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) influence inflammation. We observe negligible effect of saturated fatty acid on inflammation but marked enhancement or suppression by omega-6 and omega-3 PUFAs, respectively. Using combined lipidomic and genetic analysis, we show omega-6 PUFA enhances meta-inflammation by producing linoleic acid-derived lipid mediator 9-hydroxy-octadecadienoic acid (9-HODE). Transcriptome analysis reveals 9-HODE functions by regulating FOXO family transcription factors. We show 9-HODE activates JNK, triggering FOXO nuclear localisation and chromatin binding. FOXO TFs are important transducers of the insulin signaling pathway that are normally down-regulated by insulin. By activating FOXO, 9-HODE could antagonise insulin signaling providing a molecular conduit linking changes in dietary fatty acid balance, meta-inflammation, and insulin resistance.

Integrated eicosanoid lipidomics and gene expression reveal decreased prostaglandin catabolism and increased 5-lipoxygenase expression in aggressive subtypes of endometrial cancer.

Eicosanoids comprise a diverse group of bioactive lipids which orchestrate inflammation, immunity, and tissue homeostasis, and whose dysregulation has been implicated in carcinogenesis. Among the various eicosanoid metabolic pathways, studies of their role in endometrial cancer (EC) have very much been confined to the COX-2 pathway. This study aimed to determine changes in epithelial eicosanoid metabolic gene expression in endometrial carcinogenesis; to integrate these with eicosanoid profiles in matched clinical specimens; and, finally, to investigate the prognostic value of candidate eicosanoid metabolic enzymes. Eicosanoids and related mediators were profiled using liquid chromatography-tandem mass spectrometry in fresh frozen normal, hyperplastic, and cancerous (types I and II) endometrial specimens (n = 192). Sample-matched epithelia were isolated by laser capture microdissection and whole genome expression analysis was performed using microarrays. Integration of eicosanoid and gene expression data showed that the accepted paradigm of increased COX-2-mediated prostaglandin production does not apply in EC carcinogenesis. Instead, there was evidence for decreased PGE2 /PGF2α inactivation via 15-hydroxyprostaglandin dehydrogenase (HPGD) in type II ECs. Increased expression of 5-lipoxygenase (ALOX5) mRNA was also identified in type II ECs, together with proportional increases in its product, 5-hydroxyeicosatetraenoic acid (5-HETE). Decreased HPGD and elevated ALOX5 mRNA expression were associated with adverse outcome, which was confirmed by immunohistochemical tissue microarray analysis of an independent series of EC specimens (n = 419). While neither COX-1 nor COX-2 protein expression had prognostic value, low HPGD combined with high ALOX5 expression was associated with the worst overall and progression-free survival. These findings highlight HPGD and ALOX5 as potential therapeutic targets in aggressive EC subtypes. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Effect of oral eicosapentaenoic acid on epidermal Langerhans cell numbers and PGD2 production in UVR-exposed human skin: a randomised controlled study.

Langerhans cells (LCs) are sentinels of skin's immune system, their loss from epidermis contributing to UVR suppression of cell-mediated immunity (CMI). Omega-3 polyunsaturated fatty acids show potential to reduce UVR suppression of CMI in mice and humans, potentially through modulation of LC migration. Our objectives were to examine whether eicosapentaenoic acid (EPA) ingestion influences UV-mediated effects on epidermal LC numbers and levels of immunomodulatory mediators including prostaglandin (PG)D2 , which is expressed by LC. In a double-blind randomised controlled study, healthy individuals took 5-g EPA-rich (n=40) or control (n=33) lipid for 12 weeks; UVR-exposed and unexposed skin samples were taken pre- and postsupplementation. Epidermal LC numbers were assessed by immunofluorescence for CD1a, and skin blister fluid PG and cytokines were quantified by LC-MS/MS and Luminex assay, respectively. Presupplementation, UVR reduced mean (SEM) LC number/mm2 from 913 (28) to 322 (40) (P<.001), and mean PGD2 level by 37% from 8.1 (11.6) to 5.1 (5.6) pg/µL; P<.001), while IL-8 level increased (P<.001). Despite confirmation of EPA bioavailability in red blood cells and skin in the active group, no between-group effect of EPA was found on UVR modulation of LC numbers, PGD2 or cytokine levels postsupplementation. Thus, no evidence was found for EPA reduction of photoimmunosuppression through an impact on epidermal LC numbers. Intriguingly, UVR exposure substantially reduced cutaneous PGD2 levels in humans, starkly contrasting with reported effects of UVR on other skin PG. Lowered PGD2 levels could reflect LC loss from the epidermis and/or altered dendritic cell activity and may be relevant for phototherapy of skin disease.

Bile duct-ligated mice exhibit multiple phenotypic similarities to acute decompensation patients despite histological differences.

BACKGROUND & AIMS: Patients with decompensated cirrhosis are susceptible to infection. Innate immune dysfunction and development of organ failure are considered to underlie this. A rodent model of liver disease sharing these phenotypic features would assist in vivo study of underlying mechanisms and testing of therapeutics. We evaluated three models to identify which demonstrated the greatest clinical and immunological phenotypic similarity to patients with acutely decompensated (AD) cirrhosis. METHODS: We selected Bile Duct Ligation (BDL) rats at 4 weeks, BDL mice at 14 days and Carbon tetrachloride (CCl4 ) mice at 10 weeks (with studies performed 7 days after final CCl4 infection). We examined organ dysfunction, inflammatory response to carrageenan-in-paw, plasma eicosanoid concentrations, macrophage cytokine production and responses to peritoneal infection. RESULTS: Bile duct ligation caused sarcopenia, liver, cardiovascular and renal dysfunction whereas CCl4 mice demonstrated no clinical abnormalities. BDL rodents exhibited depressed response to carrageenan-in-paw unlike CCl4 mice. BDL rats have slightly elevated plasma eicosanoid levels and plasma showed partial PGE2 -mediated immune suppression whereas CCl4 mice did not. Plasma NOx was elevated in patients with acute or chronic liver failure (AoCLF) compared to healthy volunteers and BDL rodents but not CCl4 mice. Elevated nitric oxide (NO) via inducible nitric oxide synthase (iNOS) mediates defective leucocyte trafficking in BDL rodent models. CONCLUSIONS: We conclude that BDL mice and rats are not simply models of cholestatic liver injury but may be used to study mechanisms underlying poor outcome from infection in AD and have identified elevated NO as a potential mediator of depressed leucocyte trafficking.

A randomized controlled trial of green tea catechins in protection against ultraviolet radiation-induced cutaneous inflammation.

BACKGROUND: Safe systemic protection from the health hazards of ultraviolet radiation (UVR) in sunlight is desirable. Green tea is consumed globally and is reported to have anti-inflammatory properties, which may be mediated through the impact on cyclooxygenase and lipoxygenase pathways. Recent data suggest that green tea catechins (GTCs) reduce acute UVR effects, but human trials examining their photoprotective potential are scarce. OBJECTIVE: We performed a double-blind, randomized, placebo-controlled trial to examine whether GTCs protect against clinical, histologic, and biochemical indicators of UVR-induced inflammation. DESIGN: Healthy adults (aged 18-65 y, phototypes I-II) were randomly allocated to 1350 mg encapsulated green tea extract (540 mg GTC) with 50 mg vitamin C or placebo twice daily for 3 mo. Impact on skin erythema, dermal leukocytic infiltration, and concentrations of proinflammatory eicosanoids was assessed after solar-simulated UVR challenge, and subject compliance was determined through assay of urinary GTC metabolite epigallocatechin glucuronide. RESULTS: Volunteers were assigned to the active (n = 25) or the placebo (n = 25) group. After supplementation, median (IQR) sunburn threshold (minimal erythema dose) was 28 (20-28) and 20 (20-28) mJ/cm(2) in the active and placebo groups, respectively (nonsignificant), with no difference in AUC analysis for measured erythema index after a geometric series of 10 UVR doses. Skin immunohistochemistry showed increased neutrophil and CD3(+) T-lymphocyte numbers post-UVR in both groups (P < 0.01) with no statistically significant differences between groups after supplementation. Cyclooxygenase and lipoxygenase metabolites prostaglandin E2 (vasodilator) and 12-hydroxyeicosatetraenoicacid (chemoattractant), respectively, increased after UVR (P < 0.05), with no differences between supplementation groups. CONCLUSION: Oral GTC (1080 mg/d) with vitamin C over 3 mo did not significantly reduce skin erythema, leukocyte infiltration, or eicosanoid response to UVR inflammatory challenge. This trial was registered at clinicaltrials.gov as NCT01032031.

Distribution of bioactive lipid mediators in human skin.

The skin produces bioactive lipids that participate in physiological and pathological states, including homeostasis, induction, propagation, and resolution of inflammation. However, comprehension of the cutaneous lipid complement, and contribution to differing roles of the epidermal and dermal compartments, remains incomplete. We assessed the profiles of eicosanoids, endocannabinoids, N-acyl ethanolamides, and sphingolipids, in human dermis, epidermis, and suction blister fluid. We identified 18 prostanoids, 12 hydroxy-fatty acids, 9 endocannabinoids and N-acyl ethanolamides, and 21 non-hydroxylated ceramides and sphingoid bases, several demonstrating significantly different expression in the tissues assayed. The array of dermal and epidermal fatty acids was reflected in the lipid mediators produced, whereas similarities between lipid profiles in blister fluid and epidermis indicated a primarily epidermal origin of suction blister fluid. Supplementation with omega-3 fatty acids ex vivo showed that their action is mediated through perturbation of existing species and formation of other anti-inflammatory lipids. These findings demonstrate the diversity of lipid mediators involved in maintaining tissue homeostasis in resting skin and hint at their contribution to signaling, cross-support, and functions of different skin compartments. Profiling lipid mediators in biopsies and suction blister fluid can support studies investigating cutaneous inflammatory responses, dietary manipulation, and skin diseases lacking biomarkers and therapeutic targets.

Immunosuppression in acutely decompensated cirrhosis is mediated by prostaglandin E2.

Liver disease is one of the leading causes of death worldwide. Patients with cirrhosis display an increased predisposition to and mortality from infection due to multimodal defects in the innate immune system; however, the causative mechanism has remained elusive. We present evidence that the cyclooxygenase (COX)-derived eicosanoid prostaglandin E2 (PGE2) drives cirrhosis-associated immunosuppression. We observed elevated circulating concentrations (more than seven times as high as in healthy volunteers) of PGE2 in patients with acute decompensation of cirrhosis. Plasma from these and patients with end-stage liver disease (ESLD) suppressed macrophage proinflammatory cytokine secretion and bacterial killing in vitro in a PGE2-dependent manner via the prostanoid type E receptor-2 (EP2), effects not seen with plasma from patients with stable cirrhosis (Child-Pugh score grade A). Albumin, which reduces PGE2 bioavailability, was decreased in the serum of patients with acute decompensation or ESLD (<30 mg/dl) and appears to have a role in modulating PGE2-mediated immune dysfunction. In vivo administration of human albumin solution to these patients significantly improved the plasma-induced impairment of macrophage proinflammatory cytokine production in vitro. Two mouse models of liver injury (bile duct ligation and carbon tetrachloride) also exhibited elevated PGE2, reduced circulating albumin concentrations and EP2-mediated immunosuppression. Treatment with COX inhibitors or albumin restored immune competence and survival following infection with group B Streptococcus. Taken together, human albumin solution infusions may be used to reduce circulating PGE2 levels, attenuating immune suppression and reducing the risk of infection in patients with acutely decompensated cirrhosis or ESLD.

Impact of EPA ingestion on COX- and LOX-mediated eicosanoid synthesis in skin with and without a pro-inflammatory UVR challenge--report of a randomised controlled study in humans.

SCOPE: Eicosapentaenoic acid (EPA), abundant in oily fish, is reported to reduce skin inflammation and provide photoprotection, potential mechanisms include competition with arachidonic acid (AA) for metabolism by cyclooxygenases/lipoxygenases to less pro-inflammatory mediators. We thus examine impact of EPA intake on levels of AA, EPA and their resulting eicosanoids in human skin with or without ultraviolet radiation (UVR) challenge. METHODS AND RESULTS: In a double-blind randomised controlled study, 79 females took 5 g EPA-rich or control lipid for 12 wk. Pre- and post-supplementation, red blood cell and skin polyunsaturated fatty acids were assessed by GC, and eicosanoids from unexposed and UVR-exposed skin by LC-MS/MS. Active supplementation increased red blood cell and dermal EPA versus control (both p < 0.001), lowering relative AA:EPA content (4:1 versus 15:1 and 5:1 versus 11:1, respectively; both p < 0.001). Pre-supplementation, UVR increased PGE2, 12-hydroxyeicosatetraenoic acids, 12-HEPE (all p < 0.001) and PGE3 (p < 0.05). Post-EPA, PGE2 was reduced in unchallenged skin (p < 0.05) while EPA-derived PGE3 (non-sign) and 12-HEPE (p < 0.01) were elevated post-UVR. Thus, post-EPA, PGE2 :PGE3 was lower in unchallenged (12:1 versus 28:1; p < 0.05) and UVR exposed (12:1 versus 54:1; p < 0.01) skin; 12-hydroxyeicosatetraenoic acids:12-HEPE was lower in UVR-exposed skin (3:1 versus 11:1; p < 0.001). CONCLUSION: Dietary EPA augments skin EPA:AA content, shifting eicosanoid synthesis towards less pro-inflammatory species, and promoting a regulatory milieu under basal conditions and in response to inflammatory insult.

Inhibition of the HER2 pathway by n-3 polyunsaturated fatty acids prevents breast cancer in fat-1 transgenic mice.

Overexpression of the tyrosine kinase receptor, ErbB2/HER2/Neu, occurs in 25-30% of invasive breast cancer (BC) with poor patient prognosis. Due to confounding factors, inconsistencies still remain regarding the protective effects of n-3 polyunsaturated fatty acids (PUFAs) on BC. We therefore evaluated whether fat-1 transgenic mice, endogenously synthesizing n-3 PUFAs from n-6 PUFAs, were protected against BC development, and we then aimed to study in vivo a mechanism potentially involved in such protection. E0771 BC cells were implanted into fat-1 and wild-type (WT) mice. After tumorigenesis examination, we analyzed the expression of proteins involved in the HER2 signaling pathway and lipidomic analyses were performed in tumor tissues and plasma. Our results showed that tumors totally disappeared by day 15 in fat-1 mice but continued to grow in WT mice. This prevention can be related in part to significant repression of the HER2/ß-catenin signaling pathway and formation of significant levels of n-3 PUFA-derived bioactive mediators (particularly 15-hydroxyeicosapentaenoic acid, 17-hydroxydocosahexaenoic acid, and prostaglandin E3) in the tumors of fat-1 mice compared with WT mice. All together these data demonstrate an anti-BC effect of n-3 PUFAs through, at least in part, HER2 signaling pathway downregulation, and highlight the importance of gene-diet interactions in BC.

Aspirin-triggered 15-epi-lipoxin A4 predicts cyclooxygenase-2 in the lungs of LPS-treated mice but not in the circulation: implications for a clinical test.

Inhibition of cyclooxygenase (COX)-2 increases cardiovascular deaths. Identifying a biomarker of COX-2 is desirable but difficult, since COX-1 and COX-2 ordinarily catalyze formation of an identical product, prostaglandin H2. When acetylated by aspirin, however, COX-2 (but not COX-1) can form 15(R)-HETE, which is metabolized to aspirin-triggered lipoxin (ATL), 15-epi-lipoxin A4. Here we have used COX-1- and COX-2-knockout mice to establish whether plasma ATL could be used as a biomarker of vascular COX-2 in vivo. Vascular COX-2 was low but increased by LPS (10 mg/kg; i.p). Aspirin (10 mg/kg; i.v.) inhibited COX-1, measured as blood thromboxane and COX-2, measured as lung PGE2. Aspirin also increased the levels of ATL in the lungs of LPS-treated wild-type C57Bl6 mice (vehicle: 25.5±9.3 ng/ml; 100 mg/kg: 112.0±7.4 ng/ml; P<0.05). Despite this, ATL was unchanged in plasma after LPS and aspirin. This was true in wild-type as well as COX-1(-/-) and COX-2(-/-) mice. Thus, in mice in which COX-2 has been induced by LPS treatment, aspirin triggers detectable 15-epi-lipoxin A4 in lung tissue, but not in plasma. This important study is the first to demonstrate that while ATL can be measured in tissue, plasma ATL is not a biomarker of vascular COX-2 expression.

Randomized controlled trial of oral omega-3 PUFA in solar-simulated radiation-induced suppression of human cutaneous immune responses.

BACKGROUND: Skin cancer is a major public health concern, and the majority of cases are caused by solar ultraviolet radiation (UVR) exposure, which suppresses skin immunity. Omega-3 (n-3) PUFAs protect against photoimmunosuppression and skin cancer in mice, but the impact in humans is unknown. OBJECTIVES: We hypothesized that EPA-rich n-3 PUFA would abrogate photoimmunosuppression in humans. Therefore, a nutritional study was performed to assess the effect on UVR suppression of cutaneous cell-mediated immunity (CMI) reflected by nickel contact hypersensitivity (CHS). DESIGN: In a double-blind, randomized controlled study, 79 volunteers (nickel-allergic women, 22-60 y old, with phototype I or II) took 5 g n-3 PUFA-containing lipid (70% EPA plus 10% DHA) or a control lipid daily for 3 mo. After supplementation, nickel was applied to 3 skin sites preexposed on 3 consecutive days to 1.9, 3.8, or 7.6 J/cm(2) of solar-simulated radiation (SSR) and to 3 unexposed control sites. Nickel CHS responses were quantified after 72 h and the percentage of immunosuppression by SSR was calculated. Erythrocyte [red blood cell (RBC)] EPA was measured by using gas chromatography. RESULTS: SSR dose-related suppression of the nickel CHS response was observed in both groups. Photoimmunosuppression appeared less in the n-3 PUFA group than in the control group (not statistically significant [mean difference (95% CI): 6.9% (-2.1%, 15.9%)]). The difference was greatest at 3.8 J/cm(2) SSR [mean difference: 11% (95% CI: 0.5%, 21.4%)]. Postsupplementation RBC EPA was 4-fold higher in the n-3 PUFA group than in the control group (mean difference: 2.69% (95% CI: 2.23%, 3.14%), which confirmed the EPA bioavailability. CONCLUSION: Oral n-3 PUFAs appear to abrogate photoimmunosuppression in human skin, providing additional support for their chemopreventive role; verification of study findings is required. This trial was registered at clinicaltrials.gov as NCT01032343.

Oral green tea catechin metabolites are incorporated into human skin and protect against UV radiation-induced cutaneous inflammation in association with reduced production of pro-inflammatory eicosanoid 12-hydroxyeicosatetraenoic acid.

Green tea catechins (GTC) reduce UV radiation (UVR)-induced inflammation in experimental models, but human studies are scarce and their cutaneous bioavailability and mechanism of photoprotection are unknown. We aimed to examine oral GTC cutaneous uptake, ability to protect human skin against erythema induced by a UVR dose range and impact on potent cyclo-oxygenase- and lipoxygenase-produced mediators of UVR inflammation, PGE2 and 12-hydroxyeicosatetraenoic acid (12-HETE), respectively. In an open oral intervention study, sixteen healthy human subjects (phototype I/II) were given low-dose GTC (540 mg) with vitamin C (50 mg) daily for 12 weeks. Pre- and post-supplementation, the buttock skin was exposed to UVR and the resultant erythema quantified. Skin blister fluid and biopsies were taken from the unexposed and the UVR-exposed skin 24 h after a pro-inflammatory UVR challenge (three minimal erythema doses). Urine, skin tissue and fluid were analysed for catechin content and skin fluid for PGE2 and 12-HETE by liquid chromatography coupled to tandem MS. A total of fourteen completing subjects were supplement compliant (twelve female, median 42.5 years, range 29-59 years). Benzoic acid levels were increased in skin fluid post-supplementation (P= 0.03), and methylated gallic acid and several intact catechins and hydroxyphenyl-valerolactones were detected in the skin tissue and fluid. AUC analysis for UVR erythema revealed reduced response post-GTC (P= 0.037). Pre-supplementation, PGE2 and 12-HETE were UVR induced (P= 0.003, 0.0001). After GTC, UVR-induced 12-HETE reduced from mean 64 (sd 42) to 41 (sd 32) pg/µl (P= 0.01), while PGE2 was unaltered. Thus, GTC intake results in the incorporation of catechin metabolites into human skin associated with abrogated UVR-induced 12-HETE; this may contribute to protection against sunburn inflammation and potentially longer-term UVR-mediated damage.

Randomized placebo-controlled intervention with n-3 LC-PUFA-supplemented yoghurt: effects on circulating eicosanoids and cardiovascular risk factors.

BACKGROUND & AIMS: The study examined the value of n-3 LC-PUFA-enriched yogurt as means of improving cardiovascular health. DESIGN: Fifty three mildly hypertriacylglycerolemic subjects (TAG ≥ 1.7 mmol/L) participated in a randomized, placebo-controlled, double-blind, parallel designed study. The subjects consumed 1) control yoghurt; 2) yoghurt enriched with 0.8 g n-3 LC-PUFA/d; or 3) yoghurt enriched with 3 g n-3 LC-PUFA/d for a period of 10 wks. Blood samples were taken at the beginning and the end of the study period. RESULTS: Following daily intake of 3 g n-3 LC-PUFA for 10 weeks, n-3 LC-PUFA levels increased significantly in plasma and red blood cells (RBC) with concomitant increase in the EPA-derived mediators (PGE3, 12-, 15-, 18-HEPE) in plasma whilst cardiovascular risk factors such as HDL, TAG, AA/EPA ratio, and n-3 index were improved (P < 0.05); the decrease of TAG and increase in HDL were associated with the CD36 genotype. CONCLUSION: The observed increase of n-3 LC-PUFA in RBC and plasma lipids due to intake of n-3 LC-PUFA enriched yoghurt resulted in a reduction of cardiovascular risk factors and inflammatory mediators showing that daily consumption of n-3 PUFA enriched yoghurt can be an effective way of supplementing the daily diet and improving cardiovascular health.

Lipidomics of oxidized polyunsaturated fatty acids.

Lipid mediators are produced from the oxidation of polyunsaturated fatty acids through enzymatic and free radical-mediated reactions. When subject to oxygenation via cyclooxygenases, lipoxygenases, and cytochrome P450 monooxygenases, polyunsaturated fatty acids give rise to an array of metabolites including eicosanoids, docosanoids, and octadecanoids. These potent bioactive lipids are involved in many biochemical and signaling pathways, with inflammation being of particular importance. Moreover, because they are produced by more than one pathway and substrate, and are present in a variety of biological milieus, their analysis is not always possible with conventional assays. Liquid chromatography coupled to electrospray mass spectrometry offers a versatile and sensitive approach for the analysis of bioactive lipids, allowing specific and accurate quantitation of multiple species present in the same sample. Here we explain the principles of this approach to mediator lipidomics and present detailed protocols for the assay of enzymatically produced oxygenated metabolites of polyunsaturated fatty acids that can be tailored to answer biological questions or facilitate assessment of nutritional and pharmacological interventions.

Three-way assessment of long-chain n-3 PUFA nutrition: by questionnaire and matched blood and skin samples.

The long-chain n-3 PUFA, EPA, is believed to be important for skin health, including roles in the modulation of inflammation and protection from photodamage. FFQ and blood levels are used as non-invasive proxies for assessing skin PUFA levels, but studies examining how well these proxies reflect target organ content are lacking. In seventy-eight healthy women (mean age 42·8, range 21-60 years) residing in Greater Manchester, we performed a quantitative analysis of long-chain n-3 PUFA nutrition estimated from a self-reported FFQ (n 75) and correlated this with n-3 PUFA concentrations in erythrocytes (n 72) and dermis (n 39). Linear associations between the three n-3 PUFA measurements were assessed by Spearman correlation coefficients and agreement between these measurements was estimated. Average total dietary content of the principal long-chain n-3 PUFA EPA and DHA was 171 (SD 168) and 236 (SD 248) mg/d, respectively. EPA showed significant correlations between FFQ assessments and both erythrocyte (r 0·57, P< 0·0001) and dermal (r 0·33, P= 0·05) levels, as well as between erythrocytes and dermis (r 0·45, P= 0·008). FFQ intake of DHA and the sum of n-3 PUFA also correlated well with erythrocyte concentrations (r 0·50, P< 0·0001; r 0·27, P= 0·03). Agreement between ranked thirds of dietary intake, blood and dermis approached 50% for EPA and DHA, though gross misclassification was lower for EPA. Thus, FFQ estimates and circulating levels of the dietary long-chain n-3 PUFA, EPA, may be utilised as well-correlated measures of its dermal bioavailability.

Lipidomics of polyunsaturated-fatty-acid-derived oxygenated metabolites.

Nutritionally important PUFAs (polyunsaturated fatty acids) mediate some of their bioactivities through formation of oxygenated metabolites. These bioactive lipids are formed by COX (cyclo-oxygenase), LOX (lipoxygenase) and cytochrome-P450-catalysed reactions, as well as non-enzymatic lipid peroxidation. These reactions produce numerous species, some of which can be formed through more than one pathway. MS-based lipidomics offers the selectivity and sensitivity required for qualitative and quantitative analysis of multiple lipid species, in a variety of biological systems, and can facilitate the study of these mediators.

Fish oil supplementation alters levels of lipid mediators of inflammation in microenvironment of acute human wounds.

Chronic wounds often result from prolonged inflammation involving excessive polymorphonuclear leukocyte activity. Studies show that the ω-3 polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fish oils generate bioactive lipid mediators that reduce inflammation and polymorphonuclear leukocyte recruitment in numerous inflammatory disease models. This study's purpose was to test the hypotheses that boosting plasma levels of EPA and DHA with oral supplementation would alter lipid mediator levels in acute wound microenvironments and reduce polymorphonuclear leukocyte levels. Eighteen individuals were randomized to 28 days of either EPA+DHA supplementation (Active Group) or placebo. After 28 days, the Active Group had significantly higher plasma levels of EPA (p<0.001) and DHA (p<0.001) than the Placebo Group and significantly lower wound fluid levels of two 15-lipoxygenase products of ω-6 polyunsaturated fatty acids (9-hydroxyoctadecadienoic acid [p=0.033] and 15-hydroxyeicosatrienoic acid [p=0.006]), at 24 hours postwounding. The Active Group also had lower mean levels of myeloperoxidase, a leukocyte marker, at 12 hours and significantly more reepithelialization on Day 5 postwounding. We suggest that lipid mediator profiles can be manipulated by altering polyunsaturated fatty acid intake to create a wound microenvironment more conducive to healing.

High pancreatic n-3 fatty acids prevent STZ-induced diabetes in fat-1 mice: inflammatory pathway inhibition.

OBJECTIVE: Because of confounding factors, the effects of dietary n-3 polyunsaturated fatty acids (PUFA) on type 1 diabetes remain to be clarified. We therefore evaluated whether fat-1 transgenic mice, a well-controlled experimental model endogenously synthesizing n-3 PUFA, were protected against streptozotocin (STZ)-induced diabetes. We then aimed to elucidate the in vivo response at the pancreatic level. RESEARCH DESIGN AND METHODS: ß-Cell destruction was produced by multiple low-doses STZ (MLD-STZ). Blood glucose level, plasma insulin level, and plasma lipid analysis were then performed. Pancreatic mRNA expression of cytokines, the monocyte chemoattractant protein, and GLUT2 were evaluated as well as pancreas nuclear factor (NF)-κB p65 and inhibitor of κB (IκB) protein expression. Insulin and cleaved caspase-3 immunostaining and lipidomic analysis were performed in the pancreas. RESULTS: STZ-induced fat-1 mice did not develop hyperglycemia compared with wild-type mice, and ß-cell destruction was prevented as evidenced by lack of histological pancreatic damage or reduced insulin level. The prevention of ß-cell destruction was associated with no proinflammatory cytokine induction (tumor necrosis factor-α, interleukin-1ß, inducible nitric oxide synthase) in the pancreas, a decreased NF-κB, and increased IκB pancreatic protein expression. In the fat-1-treated mice, proinflammatory arachidonic-derived mediators as prostaglandin E2 and 12-hydroxyeicosatetraenoic acid were decreased and the anti-inflammatory lipoxin A4 was detected. Moreover, the 18-hydroxyeicosapentaenoic acid, precursor of the anti-inflammatory resolvin E1, was highly increased. CONCLUSIONS: Collectively, these findings indicate that fat-1 mice were protected against MLD-STZ-induced diabetes and pointed out for the first time in vivo the beneficial effects of n-3 PUFA at the pancreatic level, on each step of the development of the pathology-inflammation, ß-cell damage-through cytokine response and lipid mediator production.

The polyunsaturated fatty acids, EPA and DPA exert a protective effect in the hippocampus of the aged rat.

Age is characterized by deficits in synaptic function identified by decreased performance of aged animals in spatial learning tasks and reduced ability of animals to sustain long term potentiation (LTP). Several cellular and molecular events are correlated with these deficits, many of which are indicative of age-related neuroinflammatory and oxidative cell stress. It is significant that agents which decrease microglial activation are commonly associated with restoration of function. We set out to examine whether the n-3 polyunsaturated fatty acid docosapentaenoic acid (DPA), which is a metabolite of eicosapentaenoic acid (EPA), could modulate the age-related increase in microglial activation and the associated increase in oxidative changes and therefore impact on synaptic function in aged rats. We demonstrate that docosapentaenoic acid possesses neurorestorative effects and is capable of downregulating microglial activation. The data show that it also decreases the coupled activation of sphingomyelinase and caspase 3, probably because of its ability to decrease age-related oxidative changes, and consequently attenuates the age-related decrease in spatial learning and long-term potentiation.

Quantitative analysis of surfactant deposits on human skin by liquid chromatography/electrospray ionisation tandem mass spectrometry.

Surfactants are commonly used as cleansing agents and yet there are concerns that they may also have a role in skin irritation. The lack of suitable methods for the quantitative and qualitative analysis of surfactant deposition on skin has hindered the in-depth investigation of such effects. Here, we report the application of reversed-phase liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) assays for two surfactants commonly used in consumer products, namely sodium lauryl ether sulfate (SLES) and laurylamidopropyl betaine (LAPB), to a baseline study aiming to assess deposition levels on human skin. The linearity of the assays was established at 3-20 ng, with coefficient of variation below 5%. The detection limits were 100 pg for LAPB and 1 ng for SLES; quantitation limits were 500 pg for LAPB and 2.5 ng for SLES. The baseline study was conducted using a panel of 40 healthy volunteers. Skin extract samples were taken in triplicate from forearms, using ethanol. SLES was detected on most volunteers, with 75% of them having SLES deposits in the range of 100-600 ng/cm(2). LAPB was detected on the skin of all volunteers with 85% of them having deposit levels within the concentration range of 1-100 ng/cm(2). These results demonstrate the extent to which commonly used surfactants remain on the skin during the day. The analytical methods reported here can be applied to the investigation of surfactants in relation to general skin condition and to the development and optimisation of new consumer wash products.