Omega‐3 fatty acids protect from colitis via an Alox15‐derived eicosanoid

An increased omega-3 polyunsaturated fatty acid (n-3 PUFA) tissue status can lead to a significant formation of anti-inflammatory lipid mediators and effective reduction in inflammation and tissue injury in murine colitis. Arachidonic acid lipoxygenases (ALOX) have been implicated in the pathogenesis of inflammatory bowel disease as well as in the formation of pro- and anti-inflammatory lipid mediators. To explore the role of Alox15 in the protective response found in fat1 transgenic mice with endogenously increased n-3 PUFA tissue status fat1 transgenic mice were crossed with Alox15-deficient animals and challenged in the dextran sulfate sodium (DSS)- and the 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis model. Transgenic fat1 mice rich in endogenous n-3 PUFAs were protected from colitis. However, additional systemic inactivation of the Alox15 gene counteracted this protective effect. To explore the molecular basis for this effect Alox15 lipid metabolites derived from n-3 PUFA were analyzed in the different mice. Alox15 deficiency suppressed the formation of n-3 PUFA-derived 15-hydroxy eicosapentaenoic acid (15-HEPE). In contrast, treating mice with intraperitoneal injections of 15S-HEPE protected wild-type mice from DSS- and TNBS-induced colitis. These data suggest that the anti-colitis effect of increased n-3 PUFA in the transgenic fat1 mouse model is mediated in part via Alox15-derived 15-HEPE formation

Development of an Optimized LC-MS Method for the Detection of Specialized Pro-Resolving Mediators in Biological Samples

The cardioprotective and anti-inflammatory effects of long chain omega-3 polyunsaturated fatty acids (n3 PUFA) are believed to be partly mediated by their oxygenated metabolites (oxylipins). In the last two decades interest in a novel group of autacoids termed specialized pro-resolving mediators (SPMs) increased. These are actively involved in the resolution of inflammation. SPMs are multiple hydroxylated fatty acids including resolvins, maresins, and protectins derived from the n3 PUFA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as well as lipoxins derived from arachidonic acid (ARA). In the present paper, we developed an LC-MS/MS method for a comprehensive set of 18 SPMs derived from ARA, EPA, and DHA and integrated it into our targeted metabolomics platform. Quantification was based on external calibration utilizing five deuterated internal standards in combination with a second internal standard for quality assessment of sample preparation in each sample. The tandem mass spectrometric parameters were carefully optimized for sensitive and specific detection. The influence of source parameters of the used AB Sciex 6500 QTRAP instrument as well as electronic parameters and the selection of transitions are discussed. The method was validated/characterized based on the criteria listed in the European Medicines Agency (EMA) guideline on bioanalytical method validation and method performance is demonstrated regarding recovery of internal standards (between 78 ± 4% and 87 ± 3% from 500 μL of human serum) as well as extraction efficacy of SPMs in spiked plasma (intra-day accuracy within ±20 and ±15% at 0.1 and 0.3 nM in plasma, respectively). Based on the lower limit of quantification of 0.02–0.2 nM, corresponding to 0.18–2.7 pg on column, SPMs were generally not detectable/quantifiable in plasma and serum supporting that circulating levels of SPMs are very low, i.e., <0.1 nM in healthy subjects. Following septic shock or peritonitis, SPMs could be quantified in the samples of several patients. However, in these studies with a small number of patients no clear correlation with severity of inflammation could be observed

Childhood trauma, social cognition and schizophrenia: Specific association between physical neglect and cognitive theory of mind in homicide offenders

Schizophrenia is associated with a small, but increased risk of violent behavior, including homicide. Violent individuals with schizophrenia have elevated rates of childhood trauma and substantial social cognitive impairments. The aim of this study was to examine if childhood trauma is related to social cognition in homicide offenders with schizophrenia. We recruited 26 individuals with schizophrenia sentenced to compulsory mental care for homicide/attempted homicide and 28 non-violent schizophrenia controls. They filled out the Childhood Trauma Questionnaire (CTQ), providing scores for physical abuse, sexual abuse, emotional abuse, physical neglect and emotional neglect. Social cognition was assessed with two measures of emotion processing (Emotion in Biological Motion, Pictures of Facial Affect) and two theory of mind (ToM) tests (Hinting Task, Movie for the Assessment of Social Cognition: MASC). Spearman's rho correlation coefficients were computed, and significant results followed up with partial correlation analyses controlling for IQ. Three associations were statistically significant, all in the homicide group; between CTQ physical neglect and cognitive ToM assessed with Hinting Task and with MASC, and between CTQ emotional neglect and Hinting Task. Only the first remained significant after controlling for IQ, indicating a specific association between physical neglect and cognitive ToM in homicide offenders with schizophrenia

LC-HRMS analysis of phospholipids bearing oxylipins

Several oxylipins including hydroxy- and epoxy-polyunsaturated fatty acids (PUFA) act as lipid mediators. In biological samples they dominantly occur esterified in phospholipids (PL). Esterified oxylipins are usually quantified indirectly after alkaline hydrolysis as non-esterified oxylipins. Here, a liquid chromatography high-resolution mass spectrometry (LC-HRMS) method for the direct analysis of oxylipins bound to PL was developed. Optimized reversed phase LC separation enabled the separation of isobaric and isomeric PL from different lipid classes bearing oxylipin positional isomers, by both the polar head groups as well as the fatty acyl chains. Each individual PL bearing oxylipins was tentatively identified based on the combination of retention time, precursor ion and specific product ions. The oxylipin was characterized based on product ions resulting from the characteristic α cleavage occurring at the hydroxy/epoxy group. Phospholipid sn 1/sn 2 isomers were identified based on the neutral loss of the fatty acyl in the sn 2 position as a ketene. A total of 422 individual oxPL species from 7 different lipid classes i.e., PI, PS, PC, PE, PC P, PC O, and PE P, bearing hydroxy- and epoxy-PUFA were detected in human serum and cells. This method was applied to investigate in which PL class supplemented oxylipins are incorporated in HEK293 cells. 153 individual oxPL species were characterized and semi-quantified using one internal standard per lipid class: 20:4;15OH, 20:4;14Ep, and 20:5;14Ep were mostly bound to PI. 20:4;8Ep and 20:5;8Ep were esterified to PC and PE while other hydroxy- and epoxy-PUFA were mainly found in PC. The developed LC-HRMS method enables the direct and comprehensive analysis of PL bearing oxylipins and to investigate their biological role

Impaired Neuropsychological Profile in Homicide Offenders with Schizophrenia

Background: Our ability to predict and prevent homicides committed by individuals with schizophrenia is limited. Cognitive impairments are associated with poorer functional outcome in schizophrenia, possibly also homicide. The aim of the current study was to investigate global and specific cognition among homicide offenders with schizophrenia (HOS). Methods: Twenty-six HOS were compared to 28 individuals with schizophrenia and no history of violence (non-HOS), and a group of healthy controls (HC, n = 151). HOS and non-HOS participants were recruited from in- and outpatient units across Norway. An extensive neuropsychological test battery was administered. Results: HOS participants performed significantly weaker than HC in all cognitive domains. Further, statistically significant differences between HOS and non-HOS participants were found for IQ (d = 0.52) and verbal learning (d = 0.82), with larger impairments in the HOS compared to the non-HOS group. Conclusions: Our results indicate that HOS participants show clinically significant impairments in global and specific cognition

The “zipper model of empathy” applied to violence in schizophrenia: A search for social cognitive underpinnings of lack of empathic behavior

Background: The “zipper model of empathy” has been proposed for psychopathy. It postulates that empathic behavior may fail to arise due to impaired facial emotion recognition. In this study, we examined if the model may be of relevance for schizophrenia. Methods: In a sample of participants with schizophrenia and a history of severe interpersonal violence, associations between measures of social cognition (emotion recognition, theory of mind) and aspects of psychopathy (lack of empathy, lack of remorse) were investigated. A non-violent sample experiencing schizophrenia served as a control group. Results: Correlation analyses revealed a specific and statistically significant association between facial emotion recognition and lack of empathy in the violent sample. Follow-up analyses identified that neutral emotions were of particular importance. Logistic regression analyses confirmed that impairments in facial emotion recognition predicted levels of empathy in the violent sample experiencing schizophrenia. Conclusions: Our results suggest that the “zipper model of empathy” may be relevant for schizophrenia. The findings further point to the potential benefit of including social cognitive training in the treatment of persons with schizophrenia and a history of interpersonal aggression

LC-ESI-HRMS - lipidomics of phospholipids – Characterization of extraction, chromatography and detection parameters

Lipids are a diverse class of molecules involved in many biological functions including cell signaling or cell membrane assembly. Owing to this relevance, LC-MS/MS based lipidomics emerged as a major field in modern analytical chemistry. Here, we thoroughly characterized the influence of MS and LC settings – of a Q Exactive HF operated in Full MS/data-dependent MS2 TOP N acquisition mode - in order to optimize the semi-quantification of polar lipids. Optimization of MS-source settings improved the signal intensity by factor 3 compared to default settings. Polar lipids were separated on an ACQUITY Premier CSH C18 reversed-phase column (100 x 2.1 mm, 1.7 µm, 130 Å) during an elution window of 28 min, leading to a sufficient number of both data points across the chromatographic peaks, as well as MS2 spectra. Analysis was carried out in positive and negative ionization mode enabling the detection of a broader spectrum of lipids and to support the structural characterization of lipids. Optimal sample preparation of biological samples was achieved by liquid-liquid extraction using MeOH/MTBE resulting in an excellent extraction recovery >85% with an intra-day and inter-day variability <15%. The optimized method was applied on the investigation of changes in the phospholipid pattern in plasma from human subjects supplemented with n3-PUFA (20:5 and 22:6). The strongest increase was observed for lipids bearing 20:5, while 22:4 bearing lipids were lowered. Specifically, LPC 20:5_0:0 and PC 16:0_20:5 were found to be strongest elevated, while PE 18:0_22:4 and PC 18:2_18:2 were decreased by n3-PUFA supplementation. These results were confirmed by targeted LC-MS/MS using commercially available phospholipids as standards

Stability of oxylipins during plasma generation and long-term storage

International audienceOxidized unsaturated fatty acids - i.e. eicosanoids and other oxylipins - are lipid mediators involved in the regulation of numerous physiological functions such as inflammation, blood coagulation, vascular tone and endothelial permeability. They have raised strong interest in clinical lipidomics in order to understand their role in health and diseases and their use as biomarkers. However, before the clinical translation, it is crucial to validate the analytical reliability of oxylipins. This notably requires to assess the putative artificial formation or degradation of oxylipins by (unsuitable) blood handling during plasma generation, storage and sample preparation. Using a liquid chromatography-mass spectrometry method covering 133 oxylipins we comprehensively analyzed the total (free + esterified) oxylipin profile in plasma and investigated the influence of i) addition of additives during sample preparation, ii) different storage times and temperatures during the transitory stage of plasma generation and iii) long-term storage of plasma samples at -80 degrees C. Addition of radical scavenger butylated hydroxytoluene reduced the apparent concentrations of hydroxy-PUFA and thus should be added to the samples at the beginning of sample preparation. The concentrations of all oxylipin classes remained stable (within analytical variance of 20%) during the transitory stage of plasma generation up to 24 h at 4 degrees C or 4 h at 20 degrees C before centrifugation of EDTA-whole blood and up to 5 days at - 20 degrees C after plasma separation. The variations in oxylipin concentrations did not correlate with storage time, storage temperature or stage of plasma generation. A significant increase of potentially lipoxygenase derived hydroxy-PUFA compared to immediate processing was only detected when samples were stored for longer times before centrifugation, plasma separation as well as freezing of plasma revealing residual enzymatic activity. Autoxidative rather than enzymatic processes led to a slightly increased concentration of 9-HETE when plasma samples were stored at - 80 degrees C for 15 months. Overall, we demonstrate that total plasma oxylipins are robust regarding delays during plasma generation and long-term storage at -80 degrees C supporting the application of oxylipin profiling in clinical research