Plasma and bronchoalveolar lavage fluid oxylipin levels in experimental porcine lung injury.

Inflammatory signaling pathways involving eicosanoids and other regulatory lipid mediators are a subject of intensive study, and a role for these in acute lung injury is not yet well understood. We hypothesized that oxylipin release from lung injury could be detected in bronchoalveolar lavage fluid and in plasma. In a porcine model of surfactant depletion, ventilation with hyperinflation was assessed. Bronchoalveolar lavage and plasma samples were analyzed for 37 different fatty acid metabolites (oxylipins). Over time, hyperinflation altered concentrations of 4 oxylipins in plasma (TXB2, PGE2, 15-HETE and 11-HETE), and 9 oxylipins in bronchoalveolar lavage fluid (PGF2α, PGE2, PGD2, 12,13-DiHOME, 11,12-DiHETrE, 13-HODE, 9-HODE, 15-HETE, 11-HETE). Acute lung injury caused by high tidal volume ventilation in this porcine model was associated with rapid changes in some elements of the oxylipin profile, detectable in lavage fluid, and plasma. These oxylipins may be relevant in the pathogenesis of acute lung injury by hyperinflation.

Joint and unique multiblock analysis of biological data - multiomics malaria study.

Modern profiling technologies enable us to obtain large amounts of data which can be used later for a comprehensive understanding of the studied system. Proper evaluation of such data is challenging, and cannot be carried out by bare analysis of separate data sets. Integrated approaches are necessary, because only data integration allows us to find correlation trends common for all studied data sets and reveal hidden structures not known a priori. This improves the understanding and interpretation of complex systems. Joint and Unique MultiBlock Analysis (JUMBA) is an analysis method based on the OnPLS-algorithm that decomposes a set of matrices into joint parts containing variations shared with other connected matrices and variations that are unique for each single matrix. Mapping unique variations is important from a data integration perspective, since it certainly cannot be expected that all variation co-varies. In this work we used JUMBA for the integrated analysis of lipidomic, metabolomic and oxylipins data sets obtained from profiling of plasma samples from children infected with P. falciparum malaria. P. falciparum is one of the primary contributors to childhood mortality and obstetric complications in the developing world, which makes the development of new diagnostic and prognostic tools, as well as a better understanding of the disease, of utmost importance. In the presented work, JUMBA made it possible to detect already known trends related to the disease progression, but also to discover new structures in the data connected to food intake and personal differences in metabolism. By separating the variation in each data set into joint and unique, JUMBA reduced the complexity of the analysis and facilitated the detection of samples and variables corresponding to specific structures across multiple data sets, and by doing this enabled fast interpretation of the studied system. All of this makes JUMBA a perfect choice for multiblock analysis of systems biology data.

Oxylipins in cerebrospinal fluid in clinically isolated syndrome and relapsing remitting multiple sclerosis.

Although oxylipins are involved in inflammation, data on these lipid mediators in multiple sclerosis are sparse. In this study, a panel of oxylipins were analysed swith liquid chromatography tandem mass spectrometry in cerebrospinal fluid (CSF) from 41 treatment naïve patients with clinically isolated syndrome (CIS) or relapsing remitting MS (RRMS) and 22 healthy controls. CSF levels of 9-hydroxyoctadecadienoic acid (9-HODE) and 13-hydroxyoctadecadienoic acid (13-HODE) were significantly higher in patients than in healthy controls (9-HODE median 380 nM (interquartile range 330-450 nM) in patients and 290 nM (interquartile range 250-340 nM) in controls, 13-HODE median 930 nM (interquartile range 810-1080 nM) in patients and 690 nM (interquartile range 570-760 nM) in controls, p < 0.001 in Mann-Whitney U tests). 9-HODE and 13-HODE performed well for separation of patients and healthy controls (AUC 0.85 and 0.88, respectively, in ROC curve analysis). However, baseline CSF levels of the oxylipins did not differ between patients with signs of disease activity during one, two and four years of follow-up and patients without. In conclusion, this study indicates that 9-HODE and 13-HODE levels are increased in CSF from CIS and RRMS patients compared with healthy controls, but does not support 9-HODE or 13-HODE as prognostic biomarkers of disease activity in patients during follow-up.

The oxylipin and endocannabidome responses in acute phase Plasmodium falciparum malaria in children.

BACKGROUND: Oxylipins and endocannabinoids are low molecular weight bioactive lipids that are crucial for initiation and resolution of inflammation during microbial infections. Metabolic complications in malaria are recognized contributors to severe and fatal malaria, but the impact of malaria infection on the production of small lipid derived signalling molecules is unknown. Knowledge of immunoregulatory patterns of these molecules in malaria is of great value for better understanding of the disease and improvement of treatment regimes, since the action of these classes of molecules is directly connected to the inflammatory response of the organism. METHODS: Detection of oxylipins and endocannabinoids from plasma samples from forty children with uncomplicated and severe malaria as well as twenty controls was done after solid phase extraction followed by chromatography mass spectrometry analysis. The stable isotope dilution method was used for compound quantification. Data analysis was done with multivariate (principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA®) and univariate approaches (receiver operating characteristic (ROC) curves, t tests, correlation analysis). RESULTS: Forty different oxylipin and thirteen endocannabinoid metabolites were detected in the studied samples, with one oxylipin (thromboxane B2, TXB2) in significantly lower levels and four endocannabinoids (OEA, PEA, DEA and EPEA) at significantly higher levels in infected individuals as compared to controls according to t test analysis with Bonferroni correction. Three oxylipins (13-HODE, 9-HODE and 13-oxo-ODE) were higher in severe compared to uncomplicated malaria cases according to the results from multivariate analysis. Observed changes in oxylipin levels can be connected to activation of cytochrome P450 (CYP) and 5-lipoxygenase (5-LOX) metabolic pathways in malaria infected individuals compared to controls, and related to increased levels of all linoleic acid oxylipins in severe patients compared to uncomplicated ones. The endocannabinoids were extremely responsive to malaria infection with majority of this class of molecules found at higher levels in infected individuals compared to controls. CONCLUSIONS: It was possible to detect oxylipin and endocannabinoid molecules that can be potential biomarkers for differentiation between malaria infected individuals and controls and between different classes of malaria. Metabolic pathways that could be targeted towards an adjunctive therapy in the treatment of malaria were also pinpointed.

Cord blood eicosanoid signatures and newborn gestational age.

Beyond prostaglandins, the function of eicosanoids and other oxylipins in pregnancy and labor is poorly understood. In contrast to earlier work focusing on preterm infants, we investigated how oxylipin levels in newborns (measured in cord blood) vary during the last weeks of pregnancy in 190 mother-newborns (≥37 weeks of gestation) of the ENVIRONAGE birth cohort, Belgium. We found increased levels of PGE2 (p=0.003), PGF2α (p=0.042), 8,9-DHET (p=0.037), 11-HETE (p=0.034), and 15-HETrE (p=0.008) associated with full term pregnancy compared to early term labor. Furthermore, late vs early term was associated with increased levels of PGE2 (p=0.012) and TXB2 (p=0.033), while late vs full term was associated with decreased levels of 14,15-DHET (p=0.029), 11,12-DHET (p=0.033), and 5-HETE (p=0.045). To summarize, nine eicosanoids, derived via three enzymatic pathways, were significantly associated with gestational age. Eight of these were derived from arachidonic acid, and one from dihomo-γ-linolenic acid.

Mass spectrometry profiling of oxylipins, endocannabinoids, and N-acylethanolamines in human lung lavage fluids reveals responsiveness of prostaglandin E2 and associated lipid metabolites to biodiesel exhaust exposure.

The adverse effects of petrodiesel exhaust exposure on the cardiovascular and respiratory systems are well recognized. While biofuels such as rapeseed methyl ester (RME) biodiesel may have ecological advantages, the exhaust generated may cause adverse health effects. In the current study, we investigated the responses of bioactive lipid mediators in human airways after biodiesel exhaust exposure using lipidomic profiling methods. Lipid mediator levels in lung lavage were assessed following 1-h biodiesel exhaust (average particulate matter concentration, 159 µg/m3) or filtered air exposure in 15 healthy individuals in a double-blinded, randomized, controlled, crossover study design. Bronchoscopy was performed 6 h post exposure and lung lavage fluids, i.e., bronchial wash (BW) and bronchoalveolar lavage (BAL), were sequentially collected. Mass spectrometry methods were used to detect a wide array of oxylipins (including eicosanoids), endocannabinoids, N-acylethanolamines, and related lipid metabolites in the collected BW and BAL samples. Six lipids in the human lung lavage samples were altered following biodiesel exhaust exposure, three from BAL samples and three from BW samples. Of these, elevated levels of PGE2, 12,13-DiHOME, and 13-HODE, all of which were found in BAL samples, reached Bonferroni-corrected significance. This is the first study in humans reporting responses of bioactive lipids following biodiesel exhaust exposure and the most pronounced responses were seen in the more peripheral and alveolar lung compartments, reflected by BAL collection. Since the responsiveness and diagnostic value of a subset of the studied lipid metabolites were established in lavage fluids, we conclude that our mass spectrometry profiling method is useful to assess effects of human exposure to vehicle exhaust.

Oxylipins, endocannabinoids, and related compounds in human milk: Levels and effects of storage conditions.

The presence of fatty acid derived oxylipins, endocannabinoids and related compounds in human milk may be of importance to the infant. Presently, clinically relevant protocols for storing and handling human milk that minimize error and variability in oxylipin and endocannabinoid concentrations are lacking. In this study, we compared the individual and combined effects of the following storage conditions on the stability of these fatty acid metabolites in human milk: state (fresh or frozen), storage temperature (4 °C, -20 °C or -80 °C), and duration (1 day, 1 week or 3 months). Thirteen endocannabinoids and related compounds, as well as 37 oxylipins were analyzed simultaneously by liquid chromatography coupled to tandem mass spectrometry. Twelve endocannabinoids and related compounds (2-111 nM) and 31 oxylipins (1.2 pM-1242 nM) were detected, with highest levels being found for 2-arachidonoylglycerol and 17(R)hydroxydocosahexaenoic acid, respectively. The concentrations of most endocannabinoid-related compounds and oxylipins were dependent on storage condition, and especially storage at 4 °C introduced significant variability. Our findings suggest that human milk samples should be analyzed immediately after, or within one day of collection (if stored at 4 °C). Storage at -80 °C is required for long-term preservation, and storage at -20 °C is acceptable for no more than one week. These findings provide a protocol for investigating the oxylipin and endocannabinoid metabolome in human milk, useful for future milk-related clinical studies.

Multi-platform metabolomics assays for human lung lavage fluids in an air pollution exposure study.

Metabolomics protocols are used to comprehensively characterize the metabolite content of biological samples by exploiting cutting-edge analytical platforms, such as gas chromatography (GC) or liquid chromatography (LC) coupled to mass spectrometry (MS) assays, as well as nuclear magnetic resonance (NMR) assays. We have developed novel sample preparation procedures combined with GC-MS, LC-MS, and NMR metabolomics profiling for analyzing bronchial wash (BW) and bronchoalveolar lavage (BAL) fluid from 15 healthy volunteers following exposure to biodiesel exhaust and filtered air. Our aim was to investigate the responsiveness of metabolite profiles in the human lung to air pollution exposure derived from combustion of biofuels, such as rapeseed methyl ester biodiesel, which are increasingly being promoted as alternatives to conventional fossil fuels. Our multi-platform approach enabled us to detect the greatest number of unique metabolites yet reported in BW and BAL fluid (82 in total). All of the metabolomics assays indicated that the metabolite profiles of the BW and BAL fluids differed appreciably, with 46 metabolites showing significantly different levels in the corresponding lung compartments. Furthermore, the GC-MS assay revealed an effect of biodiesel exhaust exposure on the levels of 1-monostearylglycerol, sucrose, inosine, nonanoic acid, and ethanolamine (in BAL) and pentadecanoic acid (in BW), whereas the LC-MS assay indicated a shift in the levels of niacinamide (in BAL). The NMR assay only identified lactic acid (in BW) as being responsive to biodiesel exhaust exposure. Our findings demonstrate that the proposed multi-platform approach is useful for wide metabolomics screening of BW and BAL fluids and can facilitate elucidation of metabolites responsive to biodiesel exhaust exposure. Graphical Abstract Graphical abstract illustrating the study workflow. NMR Nuclear Magnetic Resonance, LC-TOFMS Liquid chromatography-Time Of Flight Mass Spectrometry, GC Gas Chromatography-Mass spectrometry.

Association between plasma concentrations of linoleic acid-derived oxylipins and the perceived pain scores in an exploratory study in women with chronic neck pain.

BACKGROUND: Chronic musculoskeletal pain may be associated with changes in the balance of algogenic and anti-nociceptive compounds, and such changes may be visible in plasma samples. We have undertaken an exploratory study to measure the levels of endocannabinoids, related N-acylethanolamines and oxylipins (primarily those derived from linoleic acid) in plasma samples from women with chronic neck pain (NP) and chronic widespread pain (CWP), and to investigate whether the observed levels are associated with the pain experienced by these women. METHODS: Blood samples from 35 women with NP, 15 with CWP and 27 age-matched controls were analysed for the lipids using ultra performance liquid chromatography coupled to tandem mass spectrometry. Current pain ("NRSday") and the average pain during the last week ("NRSweek") were rated by the participants using a numerical rating scale. RESULTS: There were no significant differences in the plasma concentrations of the fifteen lipids investigated between the women with pain and the controls. However, significant correlations were seen for the NP group between the NRSday scores and the plasma concentrations of the linoleic acid derivatives 9- and 13-hydroxy-octadecadienoic acid (Spearman's rho values 0.51 [P = 0.0016]) and 0.53 [P = 0.0011], respectively). CONCLUSIONS: The data obtained in this exploratory study indicate that although no group differences are seen in plasma lipid concentrations, there is an association between the NRSday scores and the 9- and 13-hydroxy-octadecadienoic acid levels. Whether or not the association reflects a causality (i.e. that the circulating lipids contribute to the perceived pain of the pain participants), requires further investigation.

Validation of a tandem mass spectrometry method using combined extraction of 37 oxylipins and 14 endocannabinoid-related compounds including prostamides from biological matrices.

There is a clinical need for more relevant coverage of bioactive lipids using smaller sample volumes. Therefore, we have validated a tandem mass spectrometry method for combined solid phase extraction of 37 compounds in the oxylipin (OxL) and 14 in the endocannabinoid (eCB) metabolome, as well as prostamides. The limits of quantification (LOQ) for compounds in the eCB metabolome were in the range 0.5-1000 fg on column, intraday accuracy and precision ranges (%) were 83-125 and 0.3-17, respectively, and interday accuracy and precision ranges (%) were 80-119 and 1.2-20, respectively, dependent upon the compound and the concentration studied. Corresponding values for OxL were 0.5 fg-4.2 pg on column (LOQ), 85-115% (inter- and intraday accuracy) and <5% (precision). The combined extraction method was successfully applied to tissues, cell extracts, human plasma and milk samples. A deeper study of levels in elk, pig and cow brain, as well as cow heart and liver revealed tissue and species-specific elevation of eicosanoids: arachidonate diols, 20-HETE and 12(S)-HEPE (cow liver), LTB4 (cow brain), and monohydroxy metabolites (HETEs), epoxides and 5-oxo-ETE in elk brain, which might be caused by factors of stress and/or post-mortem reactions in the tissues.

Relative and absolute reliability of measures of linoleic acid-derived oxylipins in human plasma.

Modern analytical techniques allow for the measurement of oxylipins derived from linoleic acid in biological samples. Most validatory work has concerned extraction techniques, repeated analysis of aliquots from the same biological sample, and the influence of external factors such as diet and heparin treatment upon their levels, whereas less is known about the relative and absolute reliability of measurements undertaken on different days. A cohort of nineteen healthy males were used, where samples were taken at the same time of day on two occasions, at least 7 days apart. Relative reliability was assessed using Lin's concordance correlation coefficients (CCC) and intraclass correlation coefficients (ICC). Absolute reliability was assessed by Bland-Altman analyses. Nine linoleic acid oxylipins were investigated. ICC and CCC values ranged from acceptable (0.56 [13-HODE]) to poor (near zero [9(10)- and 12(13)-EpOME]). Bland-Altman limits of agreement were in general quite wide, ranging from ±0.5 (12,13-DiHOME) to ±2 (9(10)-EpOME; log10 scale). It is concluded that relative reliability of linoleic acid-derived oxylipins varies between lipids with compounds such as the HODEs showing better relative reliability than compounds such as the EpOMEs. These differences should be kept in mind when designing and interpreting experiments correlating plasma levels of these lipids with factors such as age, body mass index, rating scales etc.

Development and validation of a sensitive UPLC-ESI-MS/MS method for the simultaneous quantification of 15 endocannabinoids and related compounds in milk and other biofluids.

The endocannabinoid (eCB) system has gained an increasing interest over the past decades since the discovery of anandamide and 2-arachidonoyl glycerol (2-AG). These, and structurally related compounds, are associated with a wide variety of physiological processes. For instance, eCB levels in milk have been associated with infants' feeding and sleeping behavior. A method based on ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) was developed and validated for the simultaneous quantification of 15 eCBs and related compounds, including both fatty acid amides and glycerols. Linearity (0.9845 < R(2) < 1), limit of detection and quantification (0.52-293 pg on column), inter- and intraday accuracy (>70%) and precision (CV < 15%), stability, and recovery (in milk and plasma) were established in accordance to the U.S. Food and Drug Administration guidelines. The method was successfully applied to bovine and elk milk revealing species-specific eCB profiles, with significant different levels of 2-AG, 2-linoleoyl glycerol, docosahexaenoyl ethanolamide, palmitoyl ethanolamide, and oleoyl ethanolamide. Furthermore, stearoyl ethanolamide and docosatetraenoyl ethanolamide were only detected in elk milk. In summary, our UPLC-ESI-MS/MS method may be used for quantification of eCBs and related compounds in different biofluids and applied to investigations of the role of these emerging compounds in various physiological processes.

Feasibility and reliability of measures of bioactive lipids in human plasma and nasal mucosa.

Analysis of bioactive lipids is increasingly useful in clinical studies, and there is a need for non-invasive and easy-to-use sampling methods that meet the demands of reliability. Samples that can be taken by a non-professional and that can be taken repeatedly so as to provide more detailed information about the inflammatory process are often desired. In this study, the feasibility of non-invasive sampling of nasal mucosa and saliva for the analysis of bioactive lipid mediators (e.g. oxylipins and endocannabinoids) was evaluated in a pilot study (n = 10). In a second study, the reliability (relative and absolute) of sampling of these lipid mediators derived from nasal mucosa and from plasma was assessed by calculation of the intraclass correlation coefficient and Bland-Altman's limit of agreement. Samples were taken at the same time of day on two occasions from a cohort of individuals with and without building-related intolerance (n = 37). Nasal mucosa proved to be a suitable matrix for the analysis of bioactive lipids and was therefore included in the study on reliability together with the plasma samples. Relative reliability varied among the identified oxylipins and endocannabinoids. Arachidonic acid derivatives showed generally better reliability. Absolute reliability measures also varied indicating that only a subset of the oxylipins and endocannabinoids were suitable as biomarkers in either nasal mucosa or plasma and should therefore be used with caution for that purpose.

Relative Deficiency of Anti-Inflammatory N-Acylethanolamines Compared to Prostaglandins in Oral Lichen Planus.

Oral lichen planus (OLP) is a chronic inflammatory oromucosal disease. The N-acylethanolamines (NAEs), are a family of endogenous biologically active lipid mediators, with palmitoylethanolamide (PEA) being of particular interest here due to its anti-inflammatory and analgesic properties. In this study using oral mucosa biopsies from OLP patients and healthy controls, we investigated whether NAE synthesis was mobilized in response to the inflammation associated with OLP. PTGS2 levels, coding for cyclooxygenase-2 (COX-2), were increased approximately 4-fold in OLP compared to controls and a significant increase in the ratio of PTGS2 to NAPEPLD, the latter coding for a key enzyme in NAE synthesis, was seen. This was matched by an increased ratio of COX-2-derived prostaglandins to PEA in a second patient cohort. We conclude that there is an imbalance between prostaglandins and PEA in OLP, opening up the possibility that PEA might be a useful treatment for this disorder.

Interferon γ treatment increases endocannabinoid and related N-acylethanolamine levels in T84 human colon carcinoma cells.

BACKGROUND AND PURPOSE: Endocannabinoids and related N-acylethanolamines (NAEs) are involved in regulation of gut function, but relatively little is known as to whether inflammatory cytokines such as IFNγ affect their levels. We have investigated this in vitro using cultures of T84 colon cancer cells. EXPERIMENTAL APPROACH: T84 cells, when cultured in monolayers, differentiate to form adult colonic crypt-like cells with excellent permeability barrier properties. The integrity of the permeability barrier in these monolayers was measured using transepithelial electrical resistance (TEER). NAE levels were determined by ultra-performance liquid chromatography-tandem mass spectrometric analysis. Expression of the enzymes involved in NAE and 2-arachidonoylglycerol (2-AG) turnover were assessed with qPCR. KEY RESULTS: IFNγ treatment for 8 or 24 h increased levels of both endocannabinoids (anandamide and 2-AG) and the related NAEs. The treatment did not affect the rate of hydrolysis of either anandamide or palmitoylethanolamide by intact cells, and in both cases, fatty acid amide hydrolase (FAAH) rather than NAE-hydrolysing acid amidase (NAAA) was mainly responsible for the hydrolysis of these NAEs. IFNγ treatment reduced the TEER of the cells in a manner that was not prevented by inhibition of either FAAH or NAAA but was partially reversed by apical administration of the NAE palmitoylethanolamide. CONCLUSION AND IMPLICATIONS: IFNγ treatment mobilized endocannabinoid and related NAE levels in T84 cells. However, blockade of anandamide or NAE hydrolysis was insufficient to negate the deleterious effects of this cytokine upon the permeability barrier of the cell monolayers. LINKED ARTICLES: This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

A standardized protocol for comparable analysis of GSH/GSSG by UHPLC-ESI-MSMS for human plasma.

Variability in the levels of GSH and GSSG in plasma is suggested to derive from inadequate pre-processing methods. The aim of this study was to develop a protocol for comparable and reliable measurements of GSH/GSSG. Venous blood from 8 healthy individuals were collected and divided into 7 different pre-processing procedures. For three of the samples an extraction mixture was added after 0 (baseline), 4 and 8 min and for three of the samples the extraction mixture was added at different times during defrost. A worst case scenario where a sample was left in a cool box during 6 h was also included. The samples were analyzed with UHPLC-ESI-MSMS. A large difference in the levels of GSH and GSSG were identified and it was clearly associated with the sample handling procedures. A sample left untreated for 4 min will have significantly reduced amount of GSH. Stability tests showed that the level of GSH was reduced after 3 months in -80 °C.

A Quantitative Analysis of Colonic Mucosal Oxylipins and Endocannabinoids in Treatment-Naïve and Deep Remission Ulcerative Colitis Patients and the Potential Link With Cytokine Gene Expression.

BACKGROUND: The bioactive metabolites of omega 3 and omega 6 polyunsaturated fatty acids (ω-3 and ω-6) are known as oxylipins and endocannabinoids (eCBs). These lipid metabolites are involved in prompting and resolving the inflammatory response that leads to the onset of inflammatory bowel disease (IBD). This study aims to quantify these bioactive lipids in the colonic mucosa and to evaluate the potential link to cytokine gene expression during inflammatory events in ulcerative colitis (UC). METHODS: Colon biopsies were taken from 15 treatment-naïve UC patients, 5 deep remission UC patients, and 10 healthy controls. Thirty-five oxylipins and 11 eCBs were quantified by means of ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. Levels of mRNA for 10 cytokines were measured by reverse transcription polymerase chain reaction. RESULTS: Levels of ω-6-related oxylipins were significantly elevated in treatment-naïve patients with respect to controls, whereas the levels of ω-3 eCBs were lower. 15S-Hydroxy-eicosatrienoic acid (15S-HETrE) was significantly upregulated in UC deep remission patients compared with controls. All investigated cytokines had significantly higher mRNA levels in the inflamed mucosa of treatment-naïve UC patients. Cytokine gene expression was positively correlated with several ω-6 arachidonic acid-related oxylipins, whereas negative correlation was found with lipoxin, prostacyclin, and the eCBs. CONCLUSIONS: Increased levels of ω-6-related oxylipins and decreased levels of ω-3-related eCBs are associated with the debut of UC. This highlights the altered balance between pro- and anti-inflammatory lipid mediators in IBD and suggests potential targets for intervention.

Involvement of CYP1B1 in interferon γ-induced alterations of epithelial barrier integrity.

BACKGROUND AND PURPOSE: CYP1B1 and CYP1A1 are important extra-hepatic cytochromes, expressed in the colon and involved in the metabolism of dietary constituents and exogenous compounds. CYP1B1 expression is increased by pro-inflammatory cytokines, and it has been recently implicated in regulation of blood brain barrier function. We investigated its involvement in the increased permeability of the intestinal epithelial barrier observed in inflammatory conditions. EXPERIMENTAL APPROACH: Epithelial monolayers formed by human T84 colon carcinoma cells cultured on transwells, were disrupted by incubation with IFNγ (10 ng·mL-1 ). Monolayer integrity was measured using transepithelial electrical resistance. CYP1A1 and CYP1B1 inhibitors or inducers were applied apically. Potential mechanisms of action were investigated using RT-qPCR. KEY RESULTS: IFNγ disrupts the barrier integrity of the T84 monolayers and increases CYP1B1 and HIF1α mRNA expression. CYP1B1 induction is inhibited by the NF-κB inhibitor ammonium pyrrolidinedithiocarbamate (100 µM) but not by the HIF1α inhibitor 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (50 µM). Inhibition of CYP1B1 with the selective inhibitor 2,4,3',5'-tetramethoxystilbene (100 nM) partly reverses the effects of IFNγ on epithelial permeability. CONCLUSIONS AND IMPLICATIONS: These data suggest that increased expression of CYP1B1 is involved in the effects of IFNγ on epithelial permeability. Inhibition of CYP1B1 counteracts the alterations of epithelial barrier integrity induced by IFNγ and could thus have a therapeutic potential in disorders of intestinal permeability associated with inflammation.

Mass spectrometry profiling reveals altered plasma levels of monohydroxy fatty acids and related lipids in healthy humans after controlled exposure to biodiesel exhaust.

Experimental human exposure studies are an effective tool to study adverse health effects from acute inhalation of particulate matter and other constituents of air pollution. In this randomized and double-blinded crossover study, we investigated the systemic effect on bioactive lipid metabolite levels after controlled biodiesel exhaust exposure of healthy humans and compared it to filtered air at a separate exposure occasion. Eicosanoids and other oxylipins, as well as endocannabinoids and related lipids, were quantified in plasma from 14 healthy volunteers at baseline and at three subsequent time points (2, 6, and 24 h) after 1 h exposure sessions. Protocols based on liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS) methods were developed to detect temporal changes in circulating levels after biodiesel exhaust exposure. The exhaust was generated by a diesel engine fed with an undiluted rapeseed methyl ester fuel. Among the 51 analyzed lipid metabolites, PGF2α, 9,10-DiHOME, 9-HODE, 5-HETE, 11-HETE, 12-HETE, and DEA displayed significant responsiveness to the biodiesel exhaust exposure as opposed to filtered air. Of these, 9-HODE and 5-HETE at 24 h survived the 10% false discovery rate cutoff (p < 0.003). Hence, the majority of the responsive lipid metabolites were monohydroxy fatty acids. We conclude that it is possible to detect alterations in circulating bioactive lipid metabolites in response to biodiesel exhaust exposure using LC-MS/MS, with emphasis on metabolites with inflammation related properties and implications on cardiovascular health and disease. These observations aid future investigations on air pollution effects, especially with regard to cardiovascular outcomes.