The role of phospholipases A2 in schizophrenia

Association between PLA2 gene polymorphisms and treatment response to antipsychotic medications: A study of antipsychotic-naïve first-episode psychosis patients and nonadherent chronic psychosis patients

Here we investigated whether antipsychotic treatment was influenced by three polymorphisms: rs10798059 (BanI) in the phospholipase A2 (PLA2)G4A gene, rs4375 in PLA2G6, and rs1549637 in PLA2G4C. A total of 186 antipsychotic-naïve first-episode psychosis patients or nonadherent chronic psychosis individuals (99 males and 87 females) were genotyped by polymerase chain reaction analysis/restriction fragment length polymorphism. At baseline, and after 8 weeks of treatment with various antipsychotic medications, we assessed patients' Positive and Negative Syndrome Scale (PANSS) scores, PANSS factors, and metabolic syndrome-related parameters (fasting plasma lipid and glucose levels, and body mass index). We found that PLA2G4A polymorphism influenced changes in PANSS psychopathology, and PLA2G6 polymorphism influenced changes in PANSS psychopathology and metabolic parameters. PLA2G4C polymorphism did not show any impact on PANSS psychopathology or metabolic parameters. The polymorphisms' effect sizes were estimated as moderate to strong, with contributions ranging from around 6.2-15.7%. Furthermore, the polymorphisms' effects manifested in a gender-specific manner.

The Inflammatory Signals Associated with Psychosis: Impact of Comorbid Drug Abuse

Psychosis and substance use disorders are two diagnostic categories whose association has been studied for decades. In addition, both psychosis spectrum disorders and drug abuse have recently been linked to multiple pro-inflammatory changes in the central nervous system. We have carried out a narrative review of the literature through a holistic approach. We used PubMed as our search engine. We included in the review all relevant studies looking at pro-inflammatory changes in psychotic disorders and substance use disorders. We found that there are multiple studies that relate various pro-inflammatory lipids and proteins with psychosis and substance use disorders, with an overlap between the two. The main findings involve inflammatory mediators such as cytokines, chemokines, endocannabinoids, eicosanoids, lysophospholipds and/or bacterial products. Many of these findings are present in different phases of psychosis and in substance use disorders such as cannabis, cocaine, methamphetamines, alcohol and nicotine. Psychosis and substance use disorders may have a common origin in an abnormal neurodevelopment caused, among other factors, by a neuroinflammatory process. A possible convergent pathway is that which interrelates the transcriptional factors NFκB and PPARγ. This may have future clinical implications.

Niacin skin flush and membrane polyunsaturated fatty acids in schizophrenia from the acute state to partial remission: a dynamic relationship

Despite the consistent finding of an attenuated niacin-induced flush response in schizophrenia, its long-term stability and relationship to the membrane polyunsaturated fatty acid (PUFA) levels remain unknown. We conducted niacin skin tests and measured the membrane PUFAs using gas chromatography among 46 schizophrenia inpatients and 37 healthy controls at the baseline and the 2-month follow-up. Attenuated flush responses were persistently observed in schizophrenia patients in both acute and partial remission states, whereas an increased flush response was found in the controls. A persistent decrease in both dihomo-gamma-linolenic acid and docosahexaenoic acid and an increased turnover of arachidonic acid (ARA) via endogenous biosynthesis were found in schizophrenia patients. A composite niacin flush score by combining those with a control-to-case ratio of >1.4 (i.e., scores at 5 min of 0.1 M, 0.01 M, and 0.001 M + 10 min of 0.01 M and 0.001 M + 15 min of 0.001 M) at the baseline was correlated positively with ARA levels among controls but not among schizophrenia patients, whereas the flush score at the 2-month follow-up was correlated positively with ARA levels among patients. The 2-month persistence of attenuated niacin-induced flush response in schizophrenia patients implies that the niacin skin test might tap a long-term vulnerability to schizophrenia beyond acute exacerbation.

Evidence that complement and coagulation proteins are mediating the clinical response to omega-3 fatty acids: A mass spectrometry-based investigation in subjects at clinical high-risk for psychosis

Preliminary evidence indicates beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) in early psychosis. The present study investigates the molecular mechanism of omega-3 PUFA-associated therapeutic effects in clinical high-risk (CHR) participants. Plasma samples of 126 CHR psychosis participants at baseline and 6-months follow-up were included. Plasma protein levels were quantified using mass spectrometry and erythrocyte omega-3 PUFA levels were quantified using gas chromatography. We examined the relationship between change in polyunsaturated PUFAs (between baseline and 6-month follow-up) and follow-up plasma proteins. Using mediation analysis, we investigated whether plasma proteins mediated the relationship between change in omega-3 PUFAs and clinical outcomes. A 6-months change in omega-3 PUFAs was associated with 24 plasma proteins at follow-up. Pathway analysis revealed the complement and coagulation pathway as the main biological pathway to be associated with change in omega-3 PUFAs. Moreover, complement and coagulation pathway proteins significantly mediated the relationship between change in omega-3 PUFAs and clinical outcome at follow-up. The inflammatory protein complement C5 and protein S100A9 negatively mediated the relationship between change in omega-3 PUFAs and positive symptom severity, while C5 positively mediated the relationship between change in omega-3 and functional outcome. The relationship between change in omega-3 PUFAs and cognition was positively mediated through coagulation factor V and complement protein C1QB. Our findings provide evidence for a longitudinal association of omega-3 PUFAs with complement and coagulation protein changes in the blood. Further, the results suggest that an increase in omega-3 PUFAs decreases symptom severity and improves cognition in the CHR state through modulating effects of complement and coagulation proteins.

Dietary plant oil supplemented with arachidonic acid and eicosapentaenoic acid affects the fatty acid composition and eicosanoid metabolism of Atlantic salmon (Salmo salar L.) during smoltification

This study sought to investigate whether a "natural diet" (mimicking the fatty acid composition of freshwater aquatic insects eaten by salmon parr) during the freshwater (FW) life stage of pre-smolt Atlantic salmon (Salmo salar L.) affected red blood cells and gill fatty acid composition as well as eicosanoid metabolism in gill during smolting at different temperatures. Before being transferred to seawater (SW), salmon parr were fed with a modified (MO) diet containing vegetable oils (rapeseed, palm, and linseed oils) supplemented with eicosapentaenoic acid (EPA) and arachidonic acid (ARA) to completely replace the fish oil (FO). Fatty acid composition in red blood cells and gill tissues was determined before SW transfer and six weeks after. Additionally, the expression of genes associated with eicosanoid metabolism and Na⁺/K⁺-ATPase (NKA) activity in salmon gill was examined at different temperatures before SW transfer and 24 h after. The results showed the changes in fatty acid composition, including sum monounsaturated fatty acids (MUFAs), docosahexaenoic acid (DHA), ARA, EPA, and sum n-6 polyunsaturated fatty acids (n-6 PUFA) in both red blood cells and gill tissues at the FW stage were consistent with the fatty acid profiles of the supplied MO and FO fish diets; however sum EPA and DHA composition exhibited opposite trends to those of the FO diet. The proportion of ARA, EPA, and n-6 PUFA increased, whereas sum MUFAs and DHA decreased in the red blood cells and gill tissues of MO-fed fish compared to those fed with the FO diet at FW stage. Additionally, 5-lipoxygenase-activating protein (Flap) expression was downregulated in MO-fed fish prior to SW transfer. During the process of SW transfer at different temperatures, the MO diet remarkably suppressed NKAα1a expression in MO-fed fish both at 12 and 16 °C. The MO diet also upregulated phospholipase A2 group IV (PLA2g4) expression in gills at 8, 12, and 16 °C, but suppressed phospholipase A2 group VI (PLA2g6) expression in gills at 12 °C compared to FO-fed fish at 12 °C and MO-fed fish at 8 °C. The MO diet also upregulated Cyclooxygenase 2 (Cox-2) expression at 8 °C compared to FO-fed fish and increased Arachidonate 5-lipoxygenase (5-Lox) expression in MO-fed fish at 16 °C compared to both FO-fed fish at 16 °C and MO-fed fish at 8 °C. Our study also determined that both SW transfer water temperatures and diets during the FW period jointly influenced the mRNA expression of PLA2g4, PLA2g6, and Lpl, whereas 5-Lox was more sensitive to dietary changes. In conclusion, the MO diet affected the fatty acid composition in gill and in red blood cells. When transferred to SW, dietary ARA supplementation could promote the bioavailability for eicosanoid synthesis in gill mainly via PLA2g4 activation, and potentially inhibit the stress and inflammatory response caused by different water temperatures through dietary EPA supplementation.

Inflammation and Nitro-oxidative Stress as Drivers of Endocannabinoid System Aberrations in Mood Disorders and Schizophrenia

The endocannabinoid system (ECS) is composed of the endocannabinoid ligands anandamide (AEA) and 2-arachidonoylgycerol (2-AG), their target cannabinoid receptors (CB₁ and CB₂) and the enzymes involved in their synthesis and metabolism (N-acyltransferase and fatty acid amide hydrolase (FAAH) in the case of AEA and diacylglycerol lipase (DAGL) and monoacylglycerol lipase (MAGL) in the case of 2-AG). The origins of ECS dysfunction in major neuropsychiatric disorders remain to be determined, and this paper explores the possibility that they may be associated with chronically increased nitro-oxidative stress and activated immune-inflammatory pathways, and it examines the mechanisms which might be involved. Inflammation and nitro-oxidative stress are associated with both increased CB₁ expression, via increased activity of the NADPH oxidases NOX4 and NOX1, and increased CNR1 expression and DNA methylation; and CB₂ upregulation via increased pro-inflammatory cytokine levels, binding of the transcription factor Nrf2 to an antioxidant response element in the CNR2 promoter region and the action of miR-139. CB₁ and CB₂ have antagonistic effects on redox signalling, which may result from a miRNA-enabled negative feedback loop. The effects of inflammation and oxidative stress are detailed in respect of AEA and 2-AG levels, via effects on calcium homeostasis and phospholipase A₂ activity; on FAAH activity, via nitrosylation/nitration of functional cysteine and/or tyrosine residues; and on 2-AG activity via effects on MGLL expression and MAGL. Finally, based on these detailed molecular neurobiological mechanisms, it is suggested that cannabidiol and dimethyl fumarate may have therapeutic potential for major depressive disorder, bipolar disorder and schizophrenia.

Reduced erythrocyte membrane polyunsaturated fatty acid levels indicate diminished treatment response in patients with multi- versus first-episode schizophrenia

Antipsychotic effects seem to decrease in relapsed schizophrenia patients and the underlying mechanisms remain to be elucidated. Based on the essential role of polyunsaturated fatty acids in brain function and the treatment of schizophrenia, we hypothesize that disordered fatty acid metabolism may contribute to treatment resistance in multi-episode patients. We analyzed the erythrocyte membrane fatty acids in 327 schizophrenia patients under various episodes (numbers of patients: first-episode drug naïve 89; 2–3 episodes 110; 4–6 episodes 80; over 6 episodes 48) and 159 age- and gender-matched healthy controls. Membrane fatty acid levels and PANSS scales were assessed at baseline of antipsychotic-free period and one-month of follow-up after treatment. Totally, both saturated and unsaturated fatty acids were reduced at baseline when compared to healthy controls. Subgroup analyses among different episodes indicated that in response to atypical antipsychotic treatment, the membrane fatty acids were only increased in patients within 3 episodes, and this therapeutic effects on omega-3 index were merely present in the first episode. Results of fatty acid ratios suggested that dysregulations of enzymes such as D6 desaturase, D5 desaturase, and elongases for polyunsaturated fatty acids in patients with multi-episode schizophrenia could account for the differences. Additionally, certain fatty acid level/ratio changes were positively correlated with symptom improvement. The alterations of C22:5n3 and omega-3 index, gender, and the number of episodes were significant risk factors correlated with treatment responsiveness. Using targeted metabolomic approach, we revealed the potential mechanisms underlying abnormal fatty acid metabolism responsible for reduced treatment response in patients with multi-episode schizophrenia.

Brain Derived Neurotrophic Factor Deficiency is Associated with Cognitive Impairment and Elevated Phospholipase A2 Activity in Plasma of Mice

Decreased levels of Brain-Derived Neurotrophic Factor (BDNF) are a common finding in schizophrenia. Another well-documented protein linked to schizophrenia is intracellular Ca²⁺-independent Phospholipase (PLA2). However, the potential association between PLA2 and BDNF with regard to schizophrenia has yet to be examined. In the present study, male and female BDNF knockout mice, a possible genetic model of schizophrenia, were exposed to prenatal stress and tested in the nest test, open field test and T-maze. Following behavioral tests, whole brain and plasma samples were harvested to measure the activity of PLA2. BDNF knockout mice showed cognitive deficits in the T-maze. Furthermore, there was a quadratic association of PLA2 with performance in the open field test. Moreover, BDNF deficiency and female sex were associated with elevated plasma PLA2 levels. The cognitive impairment of BDNF heterozygous mice as well as their increased PLA2 activity in plasma is consistent with findings in schizophrenia patients. The particular elevation of PLA2 activity in females may partly explain sex differences of clinical symptoms in schizophrenia (e.g. age of onset, severity of symptoms). Additionally, PLA2 was significantly correlated with body and adrenal weight after weaning, whereby the latter emphasizes the possible connection of PLA2 with steroidogenesis.

Increased PLA2 activity in individuals at ultra-high risk for psychosis

Phospholipase A₂ is the main enzyme in the metabolism of membrane phospholipids. It comprises a family of enzymes divided into iPLA₂, cPLA₂ and sPLA₂. Studies have reported increased PLA₂ activity in psychotic patients, which suggests an accelerated breakdown of membrane phospholipids. In the present study we investigated whether increased PLA₂ activity is also present in individuals at ultra-high risk (UHR) for psychosis. One-hundred fifty adults were included in this study (85 UHR and 65 controls). UHR was assessed using the "structured interview for prodromal syndromes". PLA₂ activity was determined in platelets by a radio-enzymatic assay. We found in UHR individuals increased activities of iPLA₂ (p < 0.001) and cPLA₂ (p = 0.012) as compared to controls. No correlations were found between socio-demographic and clinical parameters and PLA₂ activity. Our findings suggest that increased PLA₂ activities may be useful as a biological risk-marker for psychotic disorders.

Drinking and smoking polygenic risk is associated with childhood and early-adulthood psychiatric and behavioral traits independently of substance use and psychiatric genetic risk

Alcohol drinking and tobacco smoking are hazardous behaviors associated with a wide range of adverse health outcomes. In this study, we explored the association of polygenic risk scores (PRS) related to drinks per week, age of smoking initiation, smoking initiation, cigarettes per day, and smoking cessation with 433 psychiatric and behavioral traits in 4498 children and young adults (aged 8-21) of European ancestry from the Philadelphia neurodevelopmental cohort. After applying a false discovery rate multiple testing correction accounting for the number of PRS and traits tested, we identified 36 associations related to psychotic symptoms, emotion and age recognition social competencies, verbal reasoning, anxiety-related traits, parents' education, and substance use. These associations were independent of the genetic correlations among the alcohol-drinking and tobacco-smoking traits and those with cognitive performance, educational attainment, risk-taking behaviors, and psychopathology. The removal of participants endorsing substance use did not affect the associations of each PRS with psychiatric and behavioral traits identified as significant in the discovery analyses. Gene-ontology enrichment analyses identified several neurobiological processes underlying mechanisms of the PRS associations we report. In conclusion, we provide novel insights into the genetic overlap of smoking and drinking behaviors in children and young adults, highlighting their independence from psychopathology and substance use.

The lipid paradox in neuroprogressive disorders: Causes and consequences

Chronic systemic inflammation is associated with an increased risk of cardiovascular disease in an environment of low low-density lipoprotein (LDL) and low total cholesterol and with the pathophysiology of neuroprogressive disorders. The causes and consequences of this lipid paradox are explored. Circulating activated neutrophils can release inflammatory molecules such as myeloperoxidase and the pro-inflammatory cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. Since activated neutrophils are associated with atherosclerosis and cardiovascular disease and with major depressive disorder, bipolar disorder and schizophrenia, it seems reasonable to hypothesise that the inflammatory molecules released by them may act as mediators of the link between systemic inflammation and the development of atherosclerosis in neuroprogressive disorders. This hypothesis is tested by considering the association at a molecular level of systemic inflammation with increased LDL oxidation; increased small dense LDL levels; increased lipoprotein (a) concentration; secretory phospholipase A₂ activation; cytosolic phospholipase A₂ activation; increased platelet activation; decreased apolipoprotein A1 levels and function; decreased paroxonase-1 activity; hyperhomocysteinaemia; and metabolic endotoxaemia. These molecular mechanisms suggest potential therapeutic targets.

Disentangling the Molecular Mechanisms of the Antidepressant Activity of Omega-3 Polyunsaturated Fatty Acid: A Comprehensive Review of the Literature

Major depressive disorders (MDDs) are often associated with a deficiency in long-chain omega-3 polyunsaturated fatty acids (ω-3 PUFAs), as well as signs of low-grade inflammation. Epidemiological and dietary studies suggest that a high intake of fish, the major source of ω-3 PUFAs, is associated with lower rates of MDDs. Meta-analyses of randomized placebo-controlled ω-3 PUFAs intervention-trials suggest that primarily eicosapentaenoic acid (EPA), but not docosahexaenoic acid (DHA), is responsible for the proposed antidepressant effect. In this review, we dissect the current biological knowledge on EPA and DHA and their bioactive lipid metabolites to search for a pharmacological explanation of this, to date, unexplained clinical observation. Through enzymatic conversion by cyclooxygenase (COX), lipoxygenase (ALOX), and cytochrome P-450 monooxygenase (CYP), EPA and DHA are metabolized to major anti-inflammatory and pro-resolving lipid mediators. In addition, both ω-3 PUFAs are precursors for endocannabinoids, with known effects on immunomodulation, neuroinflammation, food intake and mood. Finally, both ω-3 PUFAs are crucial for the structure and organization of membranes and lipid rafts. While most biological effects are shared by these two ω-3 PUFAs, some distinct features could be identified: (1) The preferential CYP monooxygenase pathway for EPA and EPA derived eicosanoids; (2) The high CB2 receptor affinities of EPA-derived EPEA and its epoxy-metabolite 17,18-EEQ-EA, while the DHA-derived endocannabinoids lack such receptor affinities; (3) The competition of EPA but not DHA with arachidonic acid (AA) for particular glycerophospholipids. EPA and AA are preferentially incorporated into phosphatidylinositols, while DHA is mainly incorporated into phosphatidyl-ethanolamine, -serine and -choline. We propose that these distinct features may explain the superior antidepressant activity of EPA rich ω-3 PUFAs and that these are potential novel targets for future antidepressant drugs.

Inflammation and JNK's Role in Niacin-GPR109A Diminished Flushed Effect in Microglial and Neuronal Cells With Relevance to Schizophrenia

Schizophrenia is a neuropsychiatric illness with no single definitive aetiology, making its treatment difficult. Antipsychotics are not fully effective because they treat psychosis rather than the cognitive or negative symptoms. Antipsychotics fail to alleviate symptoms when patients enter the chronic stage of illness. Topical application of niacin showed diminished skin flush in the majority of patients with schizophrenia compared to the general population who showed flushing. The niacin skin flush test is useful for identifying patients with schizophrenia at their ultra-high-risk stage, and understanding this pathology may introduce an effective treatment. This review aims to understand the pathology behind the diminished skin flush response, while linking it back to neurons and microglia. First, it suggests that there are altered proteins in the GPR109A-COX-prostaglandin pathway, inflammatory imbalance, and kinase signalling pathway, c-Jun N-terminal kinase (JNK), which are associated with diminished flush. Second, genes from the GPR109A-COX-prostaglandin pathway were matched against the 128-loci genome wide association study (GWAS) for schizophrenia using GeneCards, suggesting that G-coupled receptor-109A (GPR109A) may have a genetic mutation, resulting in diminished flush. This review also suggests that there may be increased pro-inflammatory mediators in the GPR109A-COX-prostaglandin pathway, which contributes to the diminished flush pathology. Increased levels of pro-inflammatory markers may induce microglial-activated neuronal death. Lastly, this review explores the role of JNK on pro-inflammatory mediators, proteins in the GPR109A-COX-prostaglandin pathway, microglial activation, and neuronal death. Inhibiting JNK may reverse the changes observed in the diminished flush response, which might make it a good therapeutic target.

Comparison of erythrocyte omega-3 index, fatty acids and molecular phospholipid species in people at ultra-high risk of developing psychosis and healthy people

People classified as ultra-high risk (UHR) of developing psychosis have reduced cellular membrane omega-3 and omega-6 polyunsaturated fatty acids (PUFA). We aimed to compare omega-3 index, fatty acids and molecular phospholipid species from erythrocytes of people with UHR (n = 285) with age-matched healthy controls (n = 120) assessed by mass spectrometry. Lower proportions of PUFA were observed in the UHR group compared to healthy controls; specifically, eicosapentaenoic acid (EPA) was 29.3% lower, docosahexaenoic acid (DHA) was 27.2% lower, arachidonic acid (AA) was 15.8% lower and the omega-3 index was 26.9% lower. The AA to EPA ratio was higher in the UHR group compared to the healthy group. Smoking status had no significant effect on PUFA levels in healthy or the UHR groups. BMI was associated with PUFA levels in the UHR group only and the statistical model only explains 2% of the variance of the PUFA levels. The proportion of nervonic acid was 64.4% higher in the UHR group compared to healthy controls. At a lipid class level, the UHR group had 16% higher concentrations of sphingomyelin (SM) and 46% lower concentrations phosphatidylethanolamine (PE) compared to healthy group. Of the 49 individual molecular phospholipids, twenty-seven phospholipid species were lower in the UHR group. In conclusion, there are clear differences in the proportions of erythrocyte fatty acids and phospholipids between UHR and healthy controls and UHR had higher concentrations of SM and lower concentrations of PE. These differences may represent a promising prodromal risk biomarker in the UHR population to aid clinical diagnosis.

Evaluation of the arachidonic acid pathway in bipolar disorder: a systematic review

Bipolar disorder (BD) is a mood psychiatric disorder described by changes between depressive, hypomanic, or manic episodes. The aimed of the present study was evaluated possible changes in the AA pathway in BD through a systematic review of observational studies. A search in the electronic databases was proceeded, on Cochrane Library, MEDLINE, EMBASE, PsycINFO, Google Scholar and the British Library for studies published until August 2020. A search strategy was developed using the terms: "Bipolar Disorder" and "Phospholipase A2" or "Arachidonic Acids" or "Cyclooxygenase 2" or "Prostaglandins E" as text words and Medical Subject Headings (i.e., MeSH and EMTREE). Seven primary studies were included in the systematic review, with a total of 246 BD patients, 20 depression patients, and 425 heathy controls (HC). The studies showed contradictory results in the AA and PLA2, no primary articles with COX and PGE2 assessments were included in this review. According to the Newcastle-Ottawa quality score scale (NOS), our systematic review presented high quality. The investigation of the inflammatory pathway of AA still needs further investigation and evidence, given the growing number of studies suggesting the efficacy of anti-inflammatory drugs as adjunctive therapy in the pharmacological treatment of BD.

The Role of Brain Cyclooxygenase-2 (Cox-2) Beyond Neuroinflammation: Neuronal Homeostasis in Memory and Anxiety

Cyclooxygenases are a group of heme-containing isozymes (namely Cox-1 and Cox-2) that catalyze the conversion of arachidonic acid to largely bioactive prostaglandins (PGs). Cox-1 is the ubiquitous housekeeping enzyme, and the mitogen-inducible Cox-2 is activated to cause inflammation. Interestingly, Cox-2 is constitutively expressed in the brain at the postsynaptic dendrites and excitatory terminals of the cortical and spinal cord neurons. Neuronal Cox-2 is activated in response to synaptic excitation to yield PGE₂, the predominant Cox-2 metabolite in the brain, which in turn stimulates the release of glutamate and neuronal firing in a retrograde fashion. Cox-2 is also engaged in the metabolism of new endocannabinoids from 2-arachidonoyl-glycerol to modulate their actions at presynaptic terminals. In addition to these interactions, the induction of neuronal Cox-2 is coupled to the trans-synaptic activation of the dopaminergic mesolimbic system and some serotoninergic receptors, which might contribute to the development of emotional behavior. Although much of the focus regarding the induction of Cox-2 in the brain has been centered on neuroinflammation-related neurodegenerative and psychiatric disorders, some evidence also suggests that Cox-2 release during neuronal signaling may be pivotal for the fine tuning of cortical networks to regulate behavior. This review compiles the evidence supporting the homeostatic role of neuronal Cox-2 in synaptic transmission and plasticity, since neuroinflammation is originally triggered by the induction of glial Cox-2 expression. The goal is to provide perspective on the roles of Cox-2 beyond neuroinflammation, such as those played in memory and anxiety, and whose evidence is still scant.

An association between niacin skin flush response and plasma triglyceride levels in patients with schizophrenia

The available data suggest that abnormalities of arachidonic acid-related signaling may be of relevance in attenuated niacin-induced flush responses and lipid and glucose metabolism disturbances, which are all common among individuals with schizophrenia. We previously demonstrated attenuated skin flush responses to niacin in patients with schizophrenia. Here we investigated whether these niacin responses might be associated with elevated plasma lipid and glucose concentrations in this patient group. We found that higher plasma triglyceride levels were associated with higher total volumetric niacin response (VNR) values and that the VNR accounted for ~14.2% of the variability in triglyceride levels. Triglyceride levels were significantly higher in patients with a positive niacin skin flush response compared to those with absent niacin skin flushing at the 5-minute interval with niacin concentrations of 0.1 and 0.01 M, and at the 10- and 15-minute intervals with a niacin concentration of 0.001 M.

A pantothenate kinase-deficient mouse model reveals a gene expression program associated with brain coenzyme a reduction

Pantothenate kinase (PanK) is the first enzyme in the coenzyme A (CoA) biosynthetic pathway. The differential expression of the four-active mammalian PanK isoforms regulates CoA levels in different tissues and PANK2 mutations lead to Pantothenate Kinase Associated Neurodegeneration (PKAN). The molecular mechanisms that potentially underlie PKAN pathophysiology are investigated in a mouse model of CoA deficiency in the central nervous system (CNS). Both PanK1 and PanK2 contribute to brain CoA levels in mice and so a mouse model with a systemic deletion of Pank1 together with neuronal deletion of Pank2 was generated. Neuronal Pank2 expression in double knockout mice decreased starting at P9-11 triggering a significant brain CoA deficiency. The depressed brain CoA in the mice correlates with abnormal forelimb flexing and weakness that, in turn, contributes to reduced locomotion and abnormal gait. Biochemical analysis reveals a reduction in short-chain acyl-CoAs, including acetyl-CoA and succinyl-CoA. Comparative gene expression analysis reveals that the CoA deficiency in brain is associated with a large elevation of Hif3a transcript expression and significant reduction of gene transcripts in heme and hemoglobin synthesis. Reduction of brain heme levels is associated with the CoA deficiency. The data suggest a response to oxygen/glucose deprivation and indicate a disruption of oxidative metabolism arising from a CoA deficiency in the CNS.

Association between PLA2G6 gene polymorphism for calcium-independent phospholipase A2 and nicotine dependence among males with schizophrenia

We investigated the relationship between the rs10798059 (BanI) and rs4375 polymorphisms in the phospholipase A2 (PLA2)G4A and PLA2G6 genes and the risk of nicotine dependence in 263 Croatian patients with schizophrenia. We also examined whether interactions between these polymorphisms and smoking contributed to schizophrenia onset and Positive and Negative Syndrome Scale (PANSS) psychopathology. We found no significant differences in the distribution of PLA2G4A genotypes and alleles according to smoking status, and no effect of the PLA2G4A genotype-smoking interaction on disease onset or PANSS. The PLA2G6-TT homozygous genotype was significantly overrepresented in male smokers compared to nonsmokers (34.7% vs. 17.1%, p < 0.05). These patients had ∼2.6-fold higher risk of becoming smokers than males with heterozygous PLA2G6-CT and homozygous PLA2G6-CC genotypes. In addition, male smokers without the PLA2G6-C allele (PLA2G6-TT homozygous) experienced earlier onset than nonsmoking homozygous PLA2G6-TT males. Thus, the PLA2G6 polymorphism affected the risk of nicotine dependence in male patients and the PLA2G6 genotype-smoking interaction was linked to the age of disease onset.

An investigation of calcium-independent phospholipase A2 (iPLA2) and cytosolic phospholipase A2 (cPLA2) in schizophrenia

Evidence indicates that abnormal phospholipase A2 (PLA2) levels and niacin insensitivity are present in individuals with schizophrenia. This study was designed to determine whether differences in plasma calcium-independent phospholipase A2 (iPLA2) and cytosolic phospholipase A2 (cPLA2) exist between those with schizophrenia and healthy controls, and to explore the correlation between PLA2s and the niacin skin reaction in schizophrenic patients. We performed ELISA experiments to measure the concentrations of plasma iPLA2 and cPLA2 and we conducted a series of niacin skin tests on schizophrenic patients from the Chinese Han population. In addition, a meta-analysis of the relationship between PLA2 and schizophrenia was conducted. The plasma concentration of iPLA2 in patients with schizophrenia was significantly higher than that in healthy controls while the plasma concentration of cPLA2 did not differ. The meta-analysis also revealed that the activity level of iPLA2 in individuals with schizophrenia was higher than that in healthy controls, whereas that of cPLA2 was not. Furthermore, a significant positive correlation was found between the concentration of iPLA2 and the score for the skin flushing response within 20 min. The abnormal plasma iPLA2 concentration and its relationship with the niacin skin test in schizophrenic patients has contributed to a deeper understanding of the pathology of schizophrenia, which may in turn provide new insights into the clinical diagnoses and treatment of schizophrenia.

BanI polymorphism of cytosolic phospholipase A2 gene and somatic symptoms in medication-free acute depressed patients

Somatic symptoms are commonly seen in patients with major depressive disorder (MDD) and might be associated with inflammatory activation. Cytosolic phospholipase A2 (cPLA2) and cyclo-oxygenase-2 (COX-2) are the key enzymes in the metabolism of polyunsaturated fatty acids (PUFAs), which in turn may play an important role in inflammation and somatic symptoms in depression. This study investigated the effects of BanI polymorphism of cPLA2 gene and COX-2 rs4648308 genotypes on somatic symptoms and inflammatory marker in patients with MDD. Eighty-two patients with MDD were assessed for their psychopathology including psychiatric and somatic symptoms, BanI polymorphism of cPLA2 and COX-2 rs4648308 genotypes and CRP levels. The results revealed that MDD patients with the cPLA2 BanI GG genotypes had higher somatic symptoms and higher levels of C-reactive protein (CRP), while no differences were found among the COX-2 rs4648308 genotypes. Inflammatory process, such as arachidonic acid cascade pathway, might help explain the effect of cPLA2 BanI polymorphism on the somatic symptoms, and may be a potential target for future investigation on treatment for MDD with somatic symptoms. However, the interpretation of the findings in this study is limited since we analyzed the data from a subset data from a larger study.

An association between the BanI polymorphism of the PLA2G4A gene for calcium-dependent phospholipase A2 and plasma glucose levels among females with schizophrenia

Abnormal glucose and lipid metabolism may be associated with altered cytosolic Ca²⁺-dependent phospholipase A2 (cPLA2) signaling in patients with schizophrenia. The relationship between schizophrenia and the functional BanI polymorphism (rs10798059 variant, A/G polymorphism) of the PLA2G4A gene for cPLA2 has been extensively investigated. We previously reported that it can influence several clinical features of schizophrenia, and it was shown to contribute to schizophrenia risk in several population studies. We performed PCR/RFLP genotyping of 263 Croatian patients (males/females: 139/124) to investigate the relationship between the BanI polymorphism and fasting plasma glucose and lipid levels in patients with schizophrenia. Our results indicate that the BanI polymorphic variant contributes significantly to plasma glucose levels in female patients. Females carrying the PLA2G4A-G allele (PLA2G4A-GG homozygous and PLA2G4A-AG heterozygous) presented with lower glucose levels than PLA2G4A-AA homozygous carriers, and the PLA2G4A genotype contributed approximately 6% of plasma glucose level variability in this group of patients.

Transcriptomics-driven lipidomics (TDL) identifies the microbiome-regulated targets of ileal lipid metabolism

The gut microbiome and lipid metabolism are both recognized as essential components in the maintenance of metabolic health. The mechanisms involved are multifactorial and (especially for microbiome) poorly defined. A strategic approach to investigate the complexity of the microbial influence on lipid metabolism would facilitate determination of relevant molecular mechanisms for microbiome-targeted therapeutics. E. coli is associated with obesity and metabolic syndrome and we used this association in conjunction with gnotobiotic models to investigate the impact of E. coli on lipid metabolism. To address the complexities of the integration of the microbiome and lipid metabolism, we developed transcriptomics-driven lipidomics (TDL) to predict the impact of E. coli colonization on lipid metabolism and established mediators of inflammation and insulin resistance including arachidonic acid metabolism, alterations in bile acids and dietary lipid absorption. A microbiome-related therapeutic approach targeting these mechanisms may therefore provide a therapeutic avenue supporting maintenance of metabolic health.

Microbes multifactorially impact host lipid metabolism bearing a significant impact in health and disease. A team led by Mojgan Masoodi and Scott Parkinson at Nestlé Institute of Health Sciences (NIHS) developed an integrative data driven approach for predictive lipidomics investigations of host-microbial impacts on lipid metabolism. Results of in-vivo studies with germ-free mice inoculated with E. coli and in-vitro studies demonstrated the multifactorial nature of the impact of E. coli on arachidonic acid metabolism in the ileum and altered host inflammation and lipid absorption. The findings provide insights into understanding the host-microbiome interactions and identifying microbiome-related solutions for maintaining health and tackling disease. The systems approach presented is applicable to investigate broad range of microbiome dependent and independent alterations in host lipid metabolism.

Effects of omega-3 PUFA on immune markers in adolescent individuals at ultra-high risk for psychosis - Results of the randomized controlled Vienna omega-3 study

Alterations of immune function have been reported in ultra-high risk (UHR) for psychosis patients causing expectations in terms of predictive meaningfulness and benefits of anti-inflammatory agents. According to a RCT in UHR-patients supplementation of omega-3 polyunsaturated fatty acids (PUFA) was effective in reducing transition to psychosis risk and to improve symptomatology. Based on preclinical findings, we now investigated state marker properties of and the influence of PUFA on immune markers in a RCT (clinical trials.gov Identifier: NCT00396643). In a longitudinal design we measured plasma levels of the pro-inflammatory interleukin 6 (IL-6), the soluble alpha (Tac) subunit of the interleukin 2 receptor (sIL-2r), and the circulating soluble form of the intercellular adhesion molecule one (sICAM-1), in 79 help-seeking UHR individuals (13-25years of age). Using linear mixed model (LMM) analysis, we investigated the effects of 12weeks supplementation of either 1.2g/d PUFA (n=38) or Placebo (n=41). At baseline, inflammatory markers were not altered in patients who later suffered transition to psychosis within one year (n=12; 11 PUFA-group, 1 PL-group). IL-6 was weakly inverse associated with omega-6 PUFA, and highly increased in nicotine users. In univariate tests of the LMM omega-3 PUFA caused a significant increase of sICAM-1 (p=0.022). PUFA did not significantly influence IL-6 or sIL-2r. The enhancement of sICAM-1 in the PUFA condition is suggestive for supportive effects on vascular immune response and immediate Th1 helper cell mediated immune answer, which was found disturbed in manifest schizophrenia, e.g. by facilitating the leukocyte adhesion and migration across the endothelium.

Low dietary intake of n-3 fatty acids, niacin, folate, and vitamin C in Korean patients with schizophrenia and the development of dietary guidelines for schizophrenia

Inappropriate dietary intake and poor nutritional status are reported to be associated with metabolic syndrome and psychopathology in patients with schizophrenia. We hypothesized that inappropriate dietary habits and insufficient dietary intake of specific nutrients are associated with schizophrenia. To test the hypothesis, we assessed the dietary habits and nutritional intake of patients with schizophrenia and then developed suitable dietary guidelines. In total, 140 subjects (73 controls and 67 patients with schizophrenia from community mental health centers) were included, and dietary intakes were analyzed using a semi-quantitative food frequency questionnaire. As a result, the proportion of overweight or obese patients was significantly higher in schizophrenia subjects (64.2%) compared with control subjects (39.7%) (P=.004). The male schizophrenia patients had significantly lower dietary intakes of protein, polyunsaturated fatty acids (PUFAs), vitamin K, niacin, folate, and vitamin C than the male control subjects. In all multiple logistic regression models, subjects with the "low" dietary intake of protein, n-3 PUFAs, niacin, folate, and vitamin C had a significantly higher odds ratios for schizophrenia compared with those with the "high" dietary intake category of each nutrient. Therefore, maintenance of a healthy body weight and sufficient dietary intake of protein, PUFAs, niacin, folate, and vitamin C are recommended for Korean patients with schizophrenia.

An association between PLA2G6 and PLA2G4C gene polymorphisms and schizophrenia risk and illness severity in a Croatian population

We investigated the allele and genotype frequency of the rs4375 and rs1549637 polymorphisms in phospholipase A2 (PLA2)G6 and PLA2G4C genes in 203 patients with schizophrenia and 191 controls in a Croatian population. We hypothesized that these polymorphic variations might influence the age of schizophrenia onset and Positive and Negative Syndrome Scale psychopathology (PANSS) data. We detected a significant overrepresentation of the PLA2G6-CT and PLA2G4C-AT genotype combination in patients compared with controls (14.7% vs. 7.3%, P < 0.05). The combined PLA2G6/PLA2G4C heterozygosity was associated with about a two-fold higher schizophrenia risk. We found no significant influence of the PLA2G6 and PLA2G4C polymorphisms on mean age at first hospital admission (P > 0.05) and that the investigated polymorphisms significantly influenced the clinical psychopathology only in male patients. The PLA2G4C polymorphism accounted for approximately 12% of negative symptom severity; whereas, the PLA2G6/PLA2G4C interaction contributed to a similar extent to total PANSS symptom variations.

Polyunsaturated fatty acid biostatus, phospholipase A2 activity and brain white matter microstructure across adolescence

Adolescence is a period of major brain white matter (WM) changes, and membrane lipid metabolism likely plays a critical role in brain WM myelination. Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential components of cell membranes including oligodendrocytes, and LC-PUFA release and turnover in membranes is regulated by phospholipase A₂ enzymes. To investigate the role of membrane lipid metabolism in healthy WM myelination across adolescence, the present study examined the relationship between membrane LC-PUFA biostatus, phospholipase A₂ activity, and brain WM microstructure in healthy subjects aged 9-20years (n=30). Diffusion tensor imaging (DTI) was performed to measure average fractional anisotropy (FA) and diffusivity (indices sensitive to WM myelination) of nine major cerebral WM tracts. Blood samples were collected to measure erythrocyte membrane fatty acid concentrations and plasma intracellular phospholipase A₂ activity (inPLA₂). Plasma inPLA₂ activity showed a significant U-curved association with WM radial diffusivity, and an inverted U-curved association with WM FA, independent of age. A significant positive linear correlation was observed between docosahexaenoic acid concentration and axial diffusivity in the corpus callosum. These findings suggest that there may be optimal physiological inPLA₂ activity levels associated with healthy WM myelination in late childhood and adolescence. Myelination may be mediated by cleavage of docosahexaenoic acid from membrane phospholipids by inPLA₂. These findings have implications for our understanding of the role of LC-PUFA homeostasis in myelin-related neurodevelopmental disorders.

Joint sparse canonical correlation analysis for detecting differential imaging genetics modules

MOTIVATION

Imaging genetics combines brain imaging and genetic information to identify the relationships between genetic variants and brain activities. When the data samples belong to different classes (e.g. disease status), the relationships may exhibit class-specific patterns that can be used to facilitate the understanding of a disease. Conventional approaches often perform separate analysis on each class and report the differences, but ignore important shared patterns.

RESULTS

In this paper, we develop a multivariate method to analyze the differential dependency across multiple classes. We propose a joint sparse canonical correlation analysis method, which uses a generalized fused lasso penalty to jointly estimate multiple pairs of canonical vectors with both shared and class-specific patterns. Using a data fusion approach, the method is able to detect differentially correlated modules effectively and efficiently. The results from simulation studies demonstrate its higher accuracy in discovering both common and differential canonical correlations compared to conventional sparse CCA. Using a schizophrenia dataset with 92 cases and 116 controls including a single nucleotide polymorphism (SNP) array and functional magnetic resonance imaging data, the proposed method reveals a set of distinct SNP-voxel interaction modules for the schizophrenia patients, which are verified to be both statistically and biologically significant.

AVAILABILITY AND IMPLEMENTATION

The Matlab code is available at https://sites.google.com/site/jianfang86/JSCCA CONTACT: wyp@tulane.eduSupplementary information: Supplementary data are available at Bioinformatics online.

Niacin Skin Sensitivity Is Increased in Adolescents at Ultra-High Risk for Psychosis

Background

Most studies provide evidence that the skin flush response to nicotinic acid (niacin) stimulation is impaired in schizophrenia. However, only little is known about niacin sensitivity in the ultra-high risk (UHR) phase of psychotic disorders.

Methods

We compared visual ratings of niacin sensitivity between adolescents at UHR for psychosis according to the one year transition outcome (UHR-T n = 11; UHR-NT n = 55) with healthy controls (HC n = 25) and first episode schizophrenia patients (FEP n = 25) treated with atypical antipsychotics.

Results

Contrary to our hypothesis niacin sensitivity of the entire UHR group was not attenuated, but significantly increased compared to the HC group, whereas no difference could be found between the UHR-T and UHR-NT groups. As expected, niacin sensitivity of FEP was attenuated compared to HC group. In UHR individuals niacin sensitivity was inversely correlated with omega-6 and -9 fatty acids (FA), but positively correlated with phospholipase A₂ (inPLA₂) activity, a marker of membrane lipid repair/remodelling.

Conclusions

Increased niacin sensitivity in UHR states likely indicates an impaired balance of eicosanoids and omega-6/-9 FA at a membrane level. Our findings suggest that the emergence of psychosis is associated with an increased mobilisation of eicosanoids prior to the transition to psychosis possibly reflecting a “pro-inflammatory state”, whereas thereafter eicosanoid mobilisation seems to be attenuated. Potential treatment implications for the UHR state should be further investigated.

Effects of omega-3 PUFA on the vitamin E and glutathione antioxidant defense system in individuals at ultra-high risk of psychosis

BACKGROUND

Oxidative stress and impaired antioxidant defenses are reported in schizophrenia and are associated with disturbed neurodevelopment, brain structural alterations, glutamatergic imbalance, increased negative symptoms, and cognitive impairment. There is evidence that oxidative stress predates the onset of acute psychotic illness. Here, we investigate the effects of omega-3 PUFA on the vitamin E and glutathione antioxidant defense system (AODS).

METHOD

In 64 help-seeking UHR-individuals (13-25 years of age), vitamin E levels and glutathione were investigated before and after 12 weeks of treatment with either 1.2g/d omega-3 (PUFA-E) or saturated fatty acids (SFA-E), with each condition also containing 30.4mg/d alpha-tocopherol to ensure absorption without additional oxidative risk.

RESULTS

In multivariate tests, the effects on the AODS (alpha-tocopherol, total glutathione) were not significantly different (p=0.13, p=0.11, respectively) between treatment conditions. According to univariate findings, only PUFA-E caused a significant alpha-tocopherol increase, while PUFA-E and SFA-E caused a significant gamma- and delta-tocopherol decrease. Total glutathione (GSHt) was decreased by PUFA-E supplementation.

CONCLUSION

Effects of the PUFA-E condition on the vitamin E and glutathione AODS could be mechanisms underlying its clinical effectiveness. In terms of the vitamin E protection system, PUFA-E seems to directly support the antioxidative defense at membrane level. The effect of PUFA-E on GSHt is not yet fully understood, but could reflect antioxidative effects, resulting in decreased demand for glutathione. It is still necessary to further clarify which type of PUFA/antioxidant combination, and in which dose, is effective at each stage of psychotic illness.

Polymorphisms in PLA2G6 and PLA2G4C genes for calcium-independent phospholipase A2 do not contribute to attenuated niacin skin flush response in schizophrenia patients

We hypothesized that attenuated niacin skin flushing in schizophrenia patients might be associated with polymorphic variants in PLA2G6 and PLA2G4C genes (rs4375 and rs1549637 variations) which encode calcium-independent phospholipase A2 beta (iPLA2β) and cytosolic phospholipase A2 gamma (cPLA2γ) enzymes. The iPLA2β and cPLA2γ may play an important role in niacin-mediated signaling; in addition to their major role - mediating phospholipids remodeling, which alters membrane receptors and signal transduction, they regulate the reservoir of arachidonic acid for prostaglandins synthesis. Skin response to topical niacin of 0.1M, 0.01M, 0.001M and 0.0001M concentrations in 75 schizophrenia patients was rated using the method of volumetric niacin response (VNR). Neither PLA2G6 nor PLA2G4C gene polymorphisms were significantly associated with VNR values. Furthermore, polymorphisms׳ synergy on niacin skin flushing was also not detected.

Genetic Sources of Subcomponents of Event-Related Potential in the Dimension of Psychosis Analyzed From the B-SNIP Study

OBJECTIVE

Biological risk factors underlying psychosis are poorly understood. Biological underpinnings of the dimension of psychosis can be derived using genetic associations with intermediate phenotypes such as subcomponents of auditory event-related potentials (ERPs). Various ERP subcomponent abnormalities in schizophrenia and psychotic bipolar disorder are heritable and are expressed in unaffected relatives, although studies investigating genetic contributions to ERP abnormalities are limited. The authors used a novel parallel independent component analysis (para-ICA) to determine which empirically derived gene clusters are associated with data-driven ERP subcomponents, assuming a complex etiology underlying psychosis.

METHOD

The authors examined the multivariate polygenic association of ERP subcomponents from 64-channel auditory oddball data in 144 individuals with schizophrenia, 210 psychotic bipolar disorder probands, and 95 healthy individuals from the multisite Bipolar-Schizophrenia Network on Intermediate Phenotypes study. Data were reduced by principal components analysis to two target and one standard ERP waveforms. Multivariate association of compressed ERP waveforms with a set of 20,329 single-nucleotide polymorphisms (SNPs) (reduced from a 1-million-SNP array) was examined using para-ICA. Genes associated with SNPs were further examined using pathway analysis tools.

RESULTS

Para-ICA identified four ERP components that were significantly correlated with three genetic components. Enrichment analysis revealed complement immune response pathway and multiple processes that significantly mediate ERP abnormalities in psychosis, including synaptic cell adhesion, axon guidance, and neurogenesis.

CONCLUSIONS

This study identified three genetic components comprising multiple genes mediating ERP subcomponent abnormalities in schizophrenia and psychotic bipolar disorder. The data suggest a possible polygenic structure comprising genes influencing key neurodevelopmental processes, neural circuitry, and brain function mediating biological pathways plausibly associated with psychosis.

Eicosanoids Derived From Arachidonic Acid and Their Family Prostaglandins and Cyclooxygenase in Psychiatric Disorders

Arachidonic acid (AA)-derived lipid mediators are called eicosanoids. Eicosanoids have emerged as key regulators of a wide variety of physiological responses and pathological processes, and control important cellular processes. AA can be converted into biologically active compounds by metabolism by cyclooxygenases (COX). Beneficial effect of COX-2 inhibitor celecoxib add-on therapy has been reported in early stage of schizophrenia. Moreover, add-on treatment of celecoxib attenuated refractory depression and bipolar depression. Further, the COX/prostaglandin E pathway play an important role in synaptic plasticity and may be included in pathophysiology in autism spectrum disorders (ASD). In this regard, plasma transferrin, which is an iron mediator related to eicosanoid signaling, may be related to social impairment of ASD. COX-2 is typically induced by inflammatory stimuli in the majority of tissues, and the only isoform responsible for propagating the inflammatory response. Thus, COX-2 inhibitors considered as the best target for Alzheimer's disease.

Omega-3 fatty acid supplementation changes intracellular phospholipase A2 activity and membrane fatty acid profiles in individuals at ultra-high risk for psychosis

The identification of an ultra-high risk (UHR) profile for psychosis and a greater understanding of its prodrome have led to increasing interest in early intervention to delay or prevent the onset of psychotic illness. In a randomized placebo-controlled trial, we have identified long-chain ω-3 (ω-3) polyunsaturated fatty acid (PUFA) supplementation as potentially useful, as it reduced the rate of transition to psychosis by 22.6% 1 year after baseline in a cohort of 81 young people at UHR of transition to psychosis. However, the mechanisms whereby the ω-3 PUFAs might be neuroprotective are incompletely understood. Here, we report on the effects of ω-3 PUFA supplementation on intracellular phospholipase A2 (inPLA(2)) activity, the main enzymes regulating phospholipid metabolism, as well as on peripheral membrane lipid profiles in the individuals who participated in this randomized placebo-controlled trial. Patients were studied cross-sectionally (n=80) and longitudinally (n=65) before and after a 12-week intervention with 1.2 g per day ω-3 PUFAs or placebo, followed by a 40-week observation period to establish the rates of transition to psychosis. We investigated inPLA(2) and erythrocyte membrane FAs in the treatment groups (ω-3 PUFAs vs placebo) and the outcome groups (psychotic vs non-psychotic). The levels of membrane ω-3 and ω-6 PUFAs and inPLA(2) were significantly related. Some of the significant associations (that is, long-chain ω-6 PUFAs, arachidonic acid) with inPLA(2) activity were in opposite directions in individuals who did (a positive correlation) and who did not (a negative correlation) transition to psychosis. Supplementation with ω-3 PUFA resulted in a significant decrease in inPLA(2) activity. We conclude that ω-3 PUFA supplementation may act by normalizing inPLA(2) activity and δ-6-desaturase-mediated metabolism of ω-3 and ω-6 PUFAs, suggesting their role in neuroprogression of psychosis.

Skin ceramide alterations in first-episode schizophrenia indicate abnormal sphingolipid metabolism

There is considerable evidence for specific pathology of lipid metabolism in schizophrenia, affecting polyunsaturated fatty acids and in particular sphingolipids. These deficits are assumed to interfere with neuronal membrane functioning and the development and maintenance of myelin sheaths. Recent studies suggest that some of these lipid pathologies might also be detected in peripheral skin tests. In this study, we examined different skin lipids and their relation to schizophrenia. We assessed epidermal lipid profiles in 22 first-episode antipsychotic-naïve schizophrenia patients and 22 healthy controls matched for age and gender using a hexan/ethanol extraction technique and combined high-performance thin-layer chromatography/gas-chromatography. We found highly significant increase of ceramide AH and NH/AS classes in patients and decrease of EOS and NP ceramide classes. This is the first demonstration of specific peripheral sphingolipid alterations in schizophrenia. The results support recent models of systemic lipid pathology and in particular of specific sphingolipids, which are crucial in neuronal membrane integrity. Given recent findings showing amelioration of psychopathology using fatty acid supplementation, our findings also bear relevance for sphingolipids as potential biomarkers of the disease.

Mass spectrometric analysis of oxidized eicosapentaenoic Acid sodium salt

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid (PUFA) with 20 carbon atoms and 5 carbon-carbon double bonds. Mammalian cells cannot synthesize long chain PUFAs such as EPA de novo, and, thus, the most effective way to enrich cells in EPA is by dietary intake of fish oils. EPA supplementation causes an increase in its concentration in plasma lipids and in cell membrane phospholipids. Many beneficial effects of EPA supplementation have been noted, including (1) the potential to sensitize cancerous tumors towards chemotherapy, (2) the promotion of cardiovascular health, and (3) the alleviation of some mental disorders, but results from clinical trials have sometimes been disparate. In this study, we report the use of mass spectrometry to investigate the autoxidation of EPA, thereby demonstrating the formation of a variety of oxidized products. The oxidative stress of the patient may affect the response to EPA and may, in part, explain divergent results from clinical trials.

A meta-analysis of the polyunsaturated fatty acid composition of erythrocyte membranes in schizophrenia

BACKGROUND

Membrane abnormalities in polyunsaturated fatty acids (PUFAs) have been reported in schizophrenia and have been associated with brain tissue loss in normal ageing. Therefore PUFA may be involved in the excessive brain tissue loss reported in schizophrenia.

METHODS

A systematic MEDLINE database search was conducted to identify studies that compared PUFAs in erythrocyte membranes in patients and controls. Patients were categorized by medication regime in medication naive first-episode patients, and patients receiving typical or atypical antipsychotics.

SAMPLE

Fourteen studies were included, comprising a total of 429 patients with schizophrenia and 444 healthy control subjects. Cohen's d effect sizes were calculated for PUFAs in erythrocyte membranes using the random-effects model. Combined Cohen's d was calculated separately for patients on different medication regime.

RESULTS

Medication-naive patients and patients taking typical antipsychotics showed significantly (p<0.01) decreased concentrations of arachidonic (AA), docosahexaenoic (DHA), and docosapentaenoic (DPA) acid. In addition, patients taking typical antipsychotics showed decreased linoleic (LA), dihomo-γ-linolenic acid (DGLA), eicosapentaenoic (EPA) and docosatetraenoic (DTA) acid (p<0.01). Patients taking atypical antipsychotics showed decreased DHA (p<0.01) only.

CONCLUSIONS

PUFA concentrations in erythrocyte membranes are decreased in schizophrenia. Of particular importance in patients are lower concentrations of DHA and AA, two fatty acids that are abundant in the brain and important precursors in the cell-signalling cascade.

Eicosapentaenoic acid interventions in schizophrenia: meta-analysis of randomized, placebo-controlled studies

BACKGROUND

Omega-3 fatty acids, in particular, eicosapentaenoic acid (EPA) have been suggested as augmentation strategies in the treatment of schizophrenia and related psychosis. Published results are conflicting, and the antipsychotic efficacy of such augmentation strategies is not well established.

METHODS

Double-blind, randomized, placebo-controlled studies using purified or EPA-enriched oils in established schizophrenia were included in a meta-analysis. The effect size of EPA on psychotic symptoms was measured using Hedges' g. Publication bias was assessed with funnel plots and Egger's intercept. Heterogeneity was assessed with Q statistic and I index. Influence of moderators was assessed with meta-regression analyses in Comprehensive Meta-analysis Software version 2.

RESULTS

The database included 167 schizophrenic subjects under the placebo arm (mean age, 37 [SD, 9.7] years; 37% females) matched with 168 schizophrenic subjects under the EPA arm (mean age, 37 [SD, 7.9] years; 36% females) (t tests P > 0.05). Meta-analysis showed no consistent significant effect for the EPA augmentation on psychotic symptoms (Hedges' g = 0.242; 95% confidence interval, 0.028-0.512, Z = 1.7531, P > 0.05). There were no significant effects for moderator variables such as age, sex, and EPA dose used in the trials. Heterogeneity across studies was small and statistically non significant (Q = 9.06; P = 0.170; I = 33.81).

CONCLUSIONS

Meta-analysis of randomized controlled trials on symptomatic outcome revealed no beneficial effect of EPA augmentation in established schizophrenia. However, no conclusion can be made for medium- to long-term effects of EPA in schizophrenia, in particular on relapse prevention in the early course of psychotic disorders.

Phospholipase A₂ activity in first episode schizophrenia: associations with symptom severity and outcome at week 12

OBJECTIVES

Intracellular phospholipases A₂ (inPLA₂) are activated during monoaminergic neurotranismision and act as key enzymes in cell membrane repair and remodelling, neuroplasticity, neurodevelopment, apoptosis, synaptic pruning, neurodegenerative processes and neuroinflammation. Several independent studies found increased inPLA₂ activity in drug-naïve first episode and chronic schizophrenia. This study investigates if inPLA₂ activity is associated with symptoms severity and treatment response in first episode schizophrenia (FES).

METHODS

InPLA₂ activity was measured in serum of 35 young FES patients (mean age: 19.36 ± 3.32, mean duration of illness: 7.53 ± 6.28 months, 16 neuroleptic-naïve) before and after 12 weeks of treatment with second-generation antipsychotic medications (olanzapine, quetiapine or risperidone), as well as in 22 healthy controls matched for age. Psychopathology and social functioning were assessed at the same time points.

RESULTS

Baseline inPLA₂ activity was significantly increased in drug-naïve and treated FES patients compared to healthy controls. Baseline inPLA₂ activity was also associated with severity of negative symptoms and lower functioning at baseline. Furthermore, baseline inPLA₂ activity was associated with improvement in negative symptoms and functioning within the first 12 weeks of treatment.

CONCLUSIONS

Intracellular PLA₂ activity is increased in first episode schizophrenia and associated with symptom severity and outcome after 12 weeks of treatment. Future studies should investigate the implications of inPLA₂ activity as a potential predictor of treatment response for different antipsychotic agents.

Phospholipase A2 and cyclooxygenase 2 genes influence the risk of interferon-alpha-induced depression by regulating polyunsaturated fatty acids levels

BACKGROUND

Phospholipase A2 (PLA2) and cyclooxygenase 2 (COX2) are the two key enzymes in the metabolism of polyunsaturated fatty acids, which in turn play an important role in cytokine-induced depression and sickness behavior.

METHODS

Patients with chronic hepatitis C viral infection (n = 132) were assessed to examine the effects of seven single nucleotide polymorphisms in COX2 and PLA2 genes on the development of depression during interferon (IFN)-alpha treatment; a subsample (n = 63) was assessed for the erythrocyte levels of the three main polyunsaturated fatty acids, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid. An independent "replication" sample of patients with major depression unrelated to cytokine treatment (n = 82) was also examined.

RESULTS

Twenty-eight percent of participants developed INF-alpha-induced depression. Participants with the PLA2 BanI GG or the COX2 rs4648308 AG genotypes had a higher risk of IFN-alpha-induced depression (odds ratio = 3.1 and 3.5, respectively). The "at risk" PLA2 genotype was associated with lower EPA levels, and the "at risk" COX2 genotype was associated with lower DHA levels, during IFN-alpha treatment. The PLA2 BanI GG polymorphism was also associated with more somatic symptoms of depression, both in patients with INF-alpha-induced depression and in the replication sample of patients with major depression.

CONCLUSIONS

Genetic variations in the COX2 and PLA2 genes increase the risk of IFN-alpha-induced depression, possibly by affecting the levels of EPA and DHA. Moreover, PLA2 genotype is associated with somatic symptoms in depression. Our study confirms the role of inflammatory mechanisms in major depression.

Lipid oxidation and peroxidation in CNS health and disease: from molecular mechanisms to therapeutic opportunities

Reactive oxygen species (ROS) are produced at low levels in mammalian cells by various metabolic processes, such as oxidative phosphorylation by the mitochondrial respiratory chain, NAD(P)H oxidases, and arachidonic acid oxidative metabolism. To maintain physiological redox balance, cells have endogenous antioxidant defenses regulated at the transcriptional level by Nrf2/ARE. Oxidative stress results when ROS production exceeds the cell's ability to detoxify ROS. Overproduction of ROS damages cellular components, including lipids, leading to decline in physiological function and cell death. Reaction of ROS with lipids produces oxidized phospholipids, which give rise to 4-hydroxynonenal, 4-oxo-2-nonenal, and acrolein. The brain is susceptible to oxidative damage due to its high lipid content and oxygen consumption. Neurodegenerative diseases (AD, ALS, bipolar disorder, epilepsy, Friedreich's ataxia, HD, MS, NBIA, NPC, PD, peroxisomal disorders, schizophrenia, Wallerian degeneration, Zellweger syndrome) and CNS traumas (stroke, TBI, SCI) are problems of vast clinical importance. Free iron can react with H(2)O(2) via the Fenton reaction, a primary cause of lipid peroxidation, and may be of particular importance for these CNS injuries and disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Atherosclerosis, the major risk factor for ischemic stroke, involves accumulation of oxidized LDL in the arteries, leading to foam cell formation and plaque development. This review will discuss the role of lipid oxidation/peroxidation in various CNS injuries/disorders.

No association between the PPARG gene and schizophrenia in a British population

It has consistently been reported that patients with schizophrenia have an increased risk of type-2 diabetes. To investigate a genetic link between these two diseases, the combined effects of the PLA2G4A, PTGS2 and PPARG genes were tested among 221 British nuclear families consisting of fathers, mothers and affected offspring with schizophrenia. A total of 10 single nucleotide polymorphisms (SNPs) were tested and the likelihood-based association analysis for nuclear families was used to analyse the genotyping data. Eight SNPs detected across the PPARG gene did not show allelic association with schizophrenia; a weak association was detected at rs2745557 in the PTGS2 locus (chi2=4.19, p=0.041) and rs10798059 in the PLA2G4A locus (chi2=4.28, p=0.039) but these associations did not survive after 10,000 permutations to correct the p-value (global p=0.246). The gene-gene interaction test did not show any evidence of either cis-phase interactions for the PLA2G4A and PTGS2 combinations or a trans-phase interaction for the PLA2G4A and PPARG combinations. The PPARG gene has been reported to be strongly associated with type-2 diabetes, but the present study did not support the hypothesis that the PPARG gene may also play an important role in the development of schizophrenia.

No association of the rs4646396 SNP in the PEMT locus with schizophrenia in a Chinese case-control sample

The present study included a total of 628 patients with schizophrenia and 588 healthy controls to replicate the genetic association between the PEMT gene and schizophreia. However, our results in this study failed to confirm our earlier finding that the C allele was preferentially transmitted by parents to their offspring affected with schizophrenia in a family-based study among the Chinese population.

Abnormal transbilayer distribution of phospholipids in red blood cell membranes in schizophrenia

Abnormalities in membrane lipids have been repeatedly reported in patients with schizophrenia. These abnormalities include decreased phosphatidylethanolamine (PE) and n-3 and n-6 polyunsaturated fatty acids in peripheral and brain cell membranes. The present study investigates the hypothesis of an overrepresentation of PE in the external leaflet of the red blood cell (RBC) membrane in patients with schizophrenia. The assumption was that this modification of PE asymmetrical distribution could explain the reported lipid membrane abnormalities. Phosphatidylethanolamine located in the external leaflet was specifically labeled in RBC membranes from 65 medicated patients with schizophrenia and 38 healthy controls. Labeled (external) and non-labeled (internal) PE and their respective fatty acid composition were analyzed by mass spectrometry. A significant increase in the percentage of external leaflet PE was found in RBC membranes in 63.1% of the patients. In this subgroup, a significant depletion of n-3 and n-6 polyunsaturated fatty acids from internally located PE was also observed. Age, sex and antipsychotic treatment were not associated with the transbilayer membrane distribution of PE. Potential mechanisms underlying these abnormalities may involve membrane phospholipid transporters or degradative enzymes involved in phospholipid metabolism. The anomaly described could characterize a subgroup among patients with schizophrenia.

Schizophrenia: from the brain to peripheral markers. A consensus paper of the WFSBP task force on biological markers

Objective. The phenotypic complexity, together with the multifarious nature of the so-called "schizophrenic psychoses", limits our ability to form a simple and logical biologically based hypothesis for the disease group. Biological markers are defined as biochemical, physiological or anatomical traits that are specific to particular conditions. An important aim of biomarker discovery is the detection of disease correlates that can be used as diagnostic tools. Method. A selective review of the WFSBP Task Force on Biological Markers in schizophrenia is provided from the central nervous system to phenotypes, functional brain systems, chromosomal loci with potential genetic markers to the peripheral systems. Results. A number of biological measures have been proposed to be correlated with schizophrenia. At present, not a single biological trait in schizophrenia is available which achieves sufficient specificity, selectivity and is based on causal pathology and predictive validity to be recommended as diagnostic marker. Conclusions. With the emergence of new technologies and rigorous phenotypic subclassification the identification of genetic bases and assessment of dynamic disease related alterations will hopefully come to a new stage in the complex field of psychiatric research.

Decreased phospholipase A2 activity in cerebrospinal fluid of patients with dementia

Phospholipase A2 (PLA2) is involved in important aspects of dementia, for example neurotransmission and memory processing, membrane function, choline availability, and antioxidative defense. Reduced PLA2-activity has been reported so far in blood samples and postmortem neuronal tissue in Alzheimer disease. For the first time, we studied PLA2 in cerebrospinal fluid (CSF) in Alzheimer disease (AD), vascular (VD), and mixed Alzheimer/vascular dementia (MD). Intracellular PLA2 was assessed in CSF of 16 AD, 12 VD, 15 MD patients, and 19 healthy control subjects. A fluorometric assay was applied using the PLA2-specific substrate NBDC6-HPC. Significantly reduced PLA2 activity was not only found in AD, but also in VD and MD. This finding was independent of demographic co-variates and medication. PLA2 results in CSF corroborate previous findings of impaired PLA2 function in Alzheimer's disease and extend these to patients with VD. They are likely to reflect an involvement of PLA2 impairment in a variety of pathomechanisms crucial in different dementia subtypes, in which disruption of cholinergic neurotransmission and disturbance of intact membrane function appear to be the key mechanisms.