Evidence for a role of the arachidonic acid cascade in affective disorders: a review

Microscale supercritical fluid extraction combined with supercritical fluid chromatography and proton-transfer-reaction ionization time-of-flight mass spectrometry for a magnitude lower limit of quantitation of lipophilic compounds

The application of proton transfer ionization reaction mass spectrometry (PTR MS) combined with microscale supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) aiming to quantitate single-cell fatty acid analysis levels was investigated. Using a microscale extraction vessel, the obtained low limits of quantitation (LLOQs) of arachidonic acid and arachidic acid were 1.2 and 2.7 fmol, respectively, by using less than 1 µL of sample on stainless steel frit. A series of phthalate, vitamin K₁, and α-tocopherol were also tested, and the LLOQ was less than one femtomole for phthalate and 35 and 13 fmol for vitamin K₁ and α-tocopherol, respectively. A microliter portion of SFE extracts was introduced into the SFC column by split injection, improving the reproducibility of the chromatography and separation efficiency. The method in the present study has great potential to quantitate lipophilic molecules on the nanogram scale of a sample without complex preparation procedures.

Metabolomic profiling relates tianeptine effectiveness with hippocampal GABA, myo-inositol, cholesterol, and fatty acid metabolism restoration in socially isolated rats

RATIONALE

Discovering biomarkers of major depressive disorder (MDD) can give a deeper understanding of this mood disorder and improve the ability to screen for, diagnose, and treat MDD.

OBJECTIVES

In this study, metabolomics was used in unraveling metabolite fluctuations of MDD and drug outcome by creating specific metabolomic fingerprints. We report metabolomic patterns of change of the hippocampus of adult male Wistar rats following chronic social isolation (CSIS) (6 weeks), an animal model of depression, and/or chronic tianeptine (Tian) treatment (10 mg kg^-1 per day) (lasting 3 weeks of 6-week CSIS), monitored by using comprehensive GC × GC-MS.

RESULTS

The comparative metabolomic analysis highlighted the role of gamma aminobutyric acid (GABA), iso-allocholate, and unsaturated fatty acid metabolism alterations following the CSIS, which was corroborated with moderate to strong negative Pearson's correlation of GABA, docosahexaenoic, 9-hexadecenoic acid, 5,8,11,14-eicosatetraynoic, and arachidonic acids with immobility behavior in the forced swim test. The antidepressant effect of Tian restored GABA levels, which was absent in Tian resilient rats. Tian decreased myo-inositol and increased TCA cycle intermediates, amino acids, and cholesterol and its metabolite. As key molecules of divergence between Tian effectiveness and resilience, metabolomics revealed myo-inositol, GABA, cholesterol, and its metabolite. A significant moderate positive correlation between myo-inositol and immobility was revealed. Tian probably acted by upregulating NMDAR's and α₂ adrenergic receptors (AR) or norepinephrine transporter in both control and stressed animals.

CONCLUSION

Metabolomics revealed several dysregulations underlying CSIS-induced depressive-like behavior and responsiveness to Tian, predominantly converging into NMDAR-mediated glutamate and myo-inositol signalization and GABA inhibitory pathways.

Attempts to Detect Lipid Metabolites from a Single Cell Using Proton-Transfer-Reaction Mass Spectrometry Coupled with Micro-Scale Supercritical Fluid Extraction: A Preliminary Study

Proton-transfer-reaction (PTR) mass spectrometry (MS), a widely used method for detecting trace-levels of volatile organic compounds in gaseous samples, can also be used for the analysis of small non-volatile molecules by using supercritical fluid as a transporter for the molecules. Supercritical fluid extraction (SFE) is a method that permits lipophilic compounds to be rapidly and selectively extracted from complex matrices. The combination of the high sensitivity of PTR MS with the SFE is a potentially novel method for analyzing small molecules in a single cell, particularly for the analysis of lipophilic compounds. We preliminarily evaluated this method for analyzing the components of a single HeLa cell that is fixed on a stainless steel frit and is then directly introduces the SFE extracts into the PTR MS. A total of 200/91 ions were observed in positive/negative ion mode time-of-flight mass spectra, and the masses of 11/10 ions could be matched to chemical formulae obtained from the LipidMaps lipids structure database. Using various authentic lipophilic samples, the method could be used to detect free fatty acids in the sub-femtomole to femtomole order in the negative ion mode, the femtomole to sub-picomole order for fat-soluble vitamins, and the picomole order for poly aromatic hydrocarbons in both the positive and negative ion mode.

Bipolar disorder and the endocannabinoid system

OBJECTIVE

Bipolar disorder (BD) is a debilitating, lifelong neuropsychiatric illness characterised by unsteady mood states which vacillate from (hypo)mania to depression. Despite the availability of pharmaceutical agents which can be effective in ameliorating the acute affective symptoms and prevent episodic relapse, BD is inadequately treated in a subset of patients. The endocannabinoid system (ECS) is known to exert neuromodulatory effects on other neurotransmitter systems critical in governing emotions. Several studies ranging from clinical to molecular, as well as anecdotal evidence, have placed a spotlight on the potential role of the ECS in the pathophysiology of BD. In this perspective, we present advantages and disadvantages of cannabis use in the management of illness course of BD and provide mechanistic insights into how this system might contribute to the pathophysiology of BD.

RESULTS

We highlight the putative role of selective cannabinoid receptor 2 (CB2) agonists in BD and briefly discuss findings which provide a rationale for targeting the ECS to assuage the symptoms of BD. Further, data encourage basic and clinical studies to determine how cannabis and cannabinoids (CBs) can affect mood and to investigate emerging CB-based options as probable treatment approaches.

CONCLUSION

The probable role of the ECS has been almost neglected in BD; however, from data available which suggest a role of ECS in mood control, it is justified to support conducting comprehensive studies to determine whether ECS manipulation could positively affect BD. Based on the limited available data, we suggest that activation of CB2 may stabilise mood in this disorder.

Decreased Prostaglandin D2 Levels in Major Depressive Disorder Are Associated with Depression-Like Behaviors

BACKGROUND

Prostaglandin (PG) D2 is the most abundant prostaglandin in the mammalian brain. The physiological and pharmacological actions of PGD2 in the central nervous system seem to be associated with some of the symptoms exhibited by patients with major depressive disorder. Previous studies have found that PGD2 synthase was decreased in the cerebrospinal fluid of major depressive disorder patients. We speculated that there may be a dysregulation of PGD2 levels in major depressive disorder.

METHODS

Ultra-performance liquid chromatography-tandem mass spectrometry coupled with a stable isotopic-labeled internal standard was used to determine PGD2 levels in the plasma of major depressive disorder patients and in the brains of depressive mice. A total of 32 drug-free major depressive disorder patients and 30 healthy controls were recruited. An animal model of depression was constructed by exposing mice to 5 weeks of chronic unpredictable mild stress. To explore the role of PGD2 in major depressive disorder, selenium tetrachloride was administered to simulate the change in PGD2 levels in mice.

RESULTS

Mice exposed to chronic unpredictable mild stress exhibited depression-like behaviors, as indicated by reduced sucrose preference and increased immobility time in the forced swimming test. PGD2 levels in the plasma of major depressive disorder patients and in the brains of depressive mice were both decreased compared with their corresponding controls. Further inhibiting PGD2 production in mice resulted in an increased immobility time in the forced swimming test that could be reversed by imipramine.

CONCLUSION

Decreased PGD2 levels in major depressive disorder are associated with depression-like behaviors.

Omega-3 polyunsaturated fatty acid supplementation and white matter changes in major depression

White matter abnormalities are implicated in major depressive disorder (MDD). As omega-3 polyunsaturated fatty acids (PUFAs) are low in MDD and affect myelination, we hypothesized that PUFA supplementation may alleviate depression through improving white matter integrity. Acutely depressed MDD patients (n = 16) and healthy volunteers (HV, n = 12) had 25-direction diffusion tensor imaging before and after 6 weeks of fish oil supplementation. Plasma phospholipid omega-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and omega-6 PUFA arachidonic acid (AA) levels were determined before and after supplementation using high-throughput extraction and gas chromatography and expressed as a percentage of total phospholipids (PUFA%). Fractional anisotropy (FA) was computed using a least-squares-fit diffusion tensor with non-linear optimization. Regression analyses were performed with changes in PUFA levels or Hamilton Depression Rating Scale scores as predictors, voxel-wise difference maps of FA as outcome, covariates age and sex, with family-wise correction for multiple comparisons. Increases in plasma phospholipid DHA% (but not EPA% or AA%) after fish oil predicted increases in FA in MDD but not HV, in a cluster including genu and body of the corpus callosum, and anterior corona radiata and cingulum (cluster-level p < 0.001, peak t-score = 8.10, p = 0.002). There was a trend for greater change in FA in MDD responders over nonresponders (t = -1.874, df = 13.56, p = 0.08). Decreased depression severity predicted increased FA in left corticospinal tract and superior longitudinal fasciculus (cluster-level p < 0.001, peak t-score = 5.04, p = 0.0001). Increased FA correlated with increased DHA% and decreased depression severity after fish oil supplementation suggests therapeutic effects of omega-3 PUFAs may be related to improvements in white matter integrity.

Role of immunological factors in the pathophysiology and diagnosis of bipolar disorder: comparison with schizophrenia

Several lines of evidence point to the key role of neurobiological mechanisms and shared genetic background in schizophrenia and bipolar disorder. For both disorders, neurodevelopmental and neurodegenerative processes have been postulated to be relevant for the pathogenesis as well as dysregulation of immuno-inflammatory pathways. Inflammation is a complex biological response to harmful stimuli and it is mediated by cytokines cascades, cellular immune responses, oxidative factors and hormone regulation. Cytokines, in particular, are supposed to play a critical role in infectious and inflammatory processes, mediating the cross-talk between the brain and the immune system; they also possibly contribute to the development of the central nervous system. From this perspective, even though mixed results have been reported, it seems that both schizophrenia and bipolar disorder are associated with an imbalance in inflammatory cytokines; in fact, some of these could represent biological markers of illness and could be possible targets for pharmacological treatments. In light of these considerations, the purpose of the present paper was to provide a comprehensive and critical review of the existing literature about immunological abnormalities in bipolar disorder with particular attention to the similarities and differences with schizophrenia.

Omega-3 fatty acid supplementation in adolescents with borderline personality disorder and ultra-high risk criteria for psychosis: a post hoc subgroup analysis of a double-blind, randomized controlled trial

OBJECTIVE

To investigate whether long-chain omega-3 (n-3) polyunsaturated fatty acids (PUFAs) improve functioning and psychiatric symptoms in young people with borderline personality disorder (BPD) who also meet ultra-high risk criteria for psychosis.

METHODS

We conducted a post hoc subgroup analysis of a double-blind, randomized controlled trial. Fifteen adolescents with BPD (mean age 16.2 years, [SD 2.1]) were randomized to either 1.2 g/day n-3 PUFAs or placebo. The intervention period was 12 weeks. Study measures included the Positive and Negative Syndrome Scale, the Montgomery-Åsberg Depression Rating Scale, and the Global Assessment of Functioning. Side effects were documented with the Udvalg for Kliniske Undersøgelser. Fatty acids in erythrocytes were analyzed using capillary gas chromatography.

RESULTS

At baseline, erythrocyte n-3 PUFA levels correlated positively with psychosocial functioning and negatively with psychopathology. By the end of the intervention, n-3 PUFAs significantly improved functioning and reduced psychiatric symptoms, compared with placebo. Side effects did not differ between the treatment groups.

CONCLUSIONS

Long-chain n-3 PUFAs should be further explored as a viable treatment strategy with minimal associated risk in young people with BPD. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT00396643).

Emerging targets in lipid-based therapy

The use of prostaglandins and NSAIDS in the clinic has proven that lipid mediators and their associated pathways make attractive therapeutic targets. When contemplating therapies involving lipid pathways, several basic agents come to mind. There are the enzymes and accessory proteins that lead to the metabolism of lipid substrates, provided through diet or through actions of lipases, the subsequent lipid products, and finally the lipid sensors or receptors. There is abundant evidence that molecules along this lipid continuum can serve as prognostic and diagnostic indicators and are in fact viable therapeutic targets. Furthermore, lipids themselves can be used as therapeutics. Despite this, the vernacular dialog pertaining to "biomarkers" does not routinely include mention of lipids, though this is rapidly changing. Collectively these agents are becoming more appreciated for their respective roles in diverse disease processes from cancer to preterm labor and are receiving their due appreciation after decades of ground work in the lipid field. By relating examples of disease processes that result from dysfunction along the lipid continuum, as well as examples of lipid therapies and emerging technologies, this review is meant to inspire further reading and discovery.

Effects of large doses of arachidonic acid added to docosahexaenoic acid on social impairment in individuals with autism spectrum disorders: a double-blind, placebo-controlled, randomized trial

Autism spectrum disorders are a neurodevelopmental disorders with reduced cortical functional connectivity relating to social cognition. Polyunsaturated fatty acids arachidonic acid (ARA) and docosahexaenoic acid (DHA) may have key role in brain network maturation. In particularly, ARA is important in signal transduction related to neuronal maturation. Supplementation with larger ARA doses added to DHA may therefore mitigate social impairment. In a 16-week, double-blind, randomized, placebo-controlled trial, we evaluated the efficacy of supplementation with large doses of ARA added to DHA (n = 7) or placebo (n = 6) in 13 participants (mean age, 14.6 [SD, 5.9] years). To examine underlying mechanisms underlying the effect of our supplementation regimen, we examined plasma levels of antioxidants transferrin and superoxide dismutase, which are useful markers of signal transduction. The outcome measures were the Social Responsiveness Scale and the Aberrant Behavior Checklist-Community. Repeated-measures analysis of variance revealed that our supplementation regimen significantly improved Aberrant Behavior Checklist-Community-measured social withdrawal and Social Responsiveness Scale-measured communication. Treatment effect sizes were more favorable for the treatment group compared with the placebo group (communication: treatment groups, 0.87 vs, placebo, 0.44; social withdrawal: treatment groups, 0.88, vs placebo, 0.54). There was a significant difference in the change in plasma transferrin levels and a trend toward a significant difference in the change in plasma superoxide dismutase levels between the 2 groups. This preliminary study suggests that supplementation with larger ARA doses added to DHA improves impaired social interaction in individuals with autism spectrum disorder by up-regulating signal transduction.

Regulation of human microsomal prostaglandin E synthase-1 by IL-1β requires a distal enhancer element with a unique role for C/EBPβ

The studies of PGE2 (prostaglandin E2) biosynthesis have focused primarily on the role of cyclo-oxygenases. Efforts have shifted towards the specific PGE2 terminal synthases, particularly mPGES-1 (microsomal PGE synthase 1), which has emerged as the crucial inducible synthase with roles in pain, cancer and inflammation. mPGES-1 is induced by pro-inflammatory cytokines with studies focusing on the proximal promoter, mediated specifically through Egr-1 (early growth-response factor 1). Numerous studies demonstrate that the mPGES-1 promoter (PTGES) alone cannot account for the level of IL-1β (interleukin 1β) induction. We identified two DNase I-hypersensitive sites within the proximal promoter near the Egr-1 element and a novel distal site near −8.6 kb. Functional analysis of the distal site revealed two elements that co-operate with basal promoter expression and a stimulus-dependent enhancer. A specific binding site for C/EBPβ (CCAAT/enhancer-binding protein β) in the enhancer was directly responsible for inducible enhancer activity. ChIP (chromatin immunoprecipitation) analysis demonstrated constitutive Egr-1 binding to the promoter and induced RNA polymerase II and C/EBPβ binding to the promoter and enhancer respectively. Knockout/knockdown studies established a functional role for C/EBPβ in mPGES-1 gene regulation and the documented interaction between Egr-1 and C/EBPβ highlights the proximal promoter co-operation with a novel distal enhancer element in regulating inducible mPGES-1 expression.

Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression

OBJECTIVE

Randomized trials of omega-3 polyunsaturated fatty acid (PUFA) treatment for depression have differed in outcome. Recent meta-analyses ascribe discrepancies to differential effects of eicosapentaenoic acid (EPA) versus docosahexaenoic acid (DHA) and to diagnostic heterogeneity. This meta-analysis tests the hypothesis that EPA is the effective component in PUFA treatment of major depressive episodes.

DATA SOURCES

PubMed/MeSH was searched for studies published in English from 1960 through June 2010 using the terms fish oils (MeSH) AND (depressive disorder [MeSH] OR bipolar depression) AND randomized controlled trial (publication type). The search was supplemented by manual bibliography review and examination of relevant review articles.

STUDY SELECTION

The search yielded 15 trials involving 916 participants. Studies were included if they had a prospective, randomized, double-blinded, placebo-controlled study design; if depressive episode was the primary complaint (with or without comorbid medical conditions); if omega-3 PUFA supplements were administered; and if appropriate outcome measures were used to assess depressed mood.

DATA EXTRACTION

Extracted data included study design, sample sizes, doses and percentages of EPA and DHA, mean ages, baseline and endpoint depression ratings and standard deviations for PUFA and placebo groups, and P values. The clinical outcome of interest was the standardized mean difference in the change from baseline to endpoint scores on a depression rating scale in subjects taking PUFA supplements versus subjects taking placebo.

DATA SYNTHESIS

In a mixed-effect model, percentage of EPA in the supplements was the fixed-effect predictor, dichotomized into 2 groups: EPA < 60% or EPA ≥ 60% of the total EPA + DHA. Secondary analyses explored the relevance of treatment duration, age, and EPA dose.

RESULTS

Supplements with EPA ≥ 60% showed benefit on standardized mean depression scores (effect size = 0.532; 95% CI, 0.277-0.733; t = 4.195; P < .001) versus supplements with EPA < 60% (effect size = -0.026; 95% CI, -0.200 to 0.148; t = -0.316; P = .756), with negligible contribution of random effects or heteroscedasticity and with no effects of treatment duration or age. Supplements with EPA < 60% were ineffective. Exploratory analyses supported a nonlinear model, with improvement determined by the dose of EPA in excess of DHA, within the range of 200 to 2,200 mg/d of EPA.

CONCLUSIONS

Supplements containing EPA ≥ 60% of total EPA + DHA, in a dose range of 200 to 2,200 mg/d of EPA in excess of DHA, were effective against primary depression. Translational studies are needed to determine the mechanisms of EPA's therapeutic benefit.

Altered arachidonic acid cascade enzymes in postmortem brain from bipolar disorder patients

Mood stabilizers that are approved for treating bipolar disorder (BD), when given chronically to rats, decrease expression of markers of the brain arachidonic metabolic cascade, and reduce excitotoxicity and neuroinflammation-induced upregulation of these markers. These observations, plus evidence for neuroinflammation and excitotoxicity in BD, suggest that arachidonic acid (AA) cascade markers are upregulated in the BD brain. To test this hypothesis, these markers were measured in postmortem frontal cortex from 10 BD patients and 10 age-matched controls. Mean protein and mRNA levels of AA-selective cytosolic phospholipase A(2) (cPLA(2)) IVA, secretory sPLA(2) IIA, cyclooxygenase (COX)-2 and membrane prostaglandin E synthase (mPGES) were significantly elevated in the BD cortex. Levels of COX-1 and cytosolic PGES (cPGES) were significantly reduced relative to controls, whereas Ca(2+)-independent iPLA(2)VIA, 5-, 12-, and 15-lipoxygenase, thromboxane synthase and cytochrome p450 epoxygenase protein and mRNA levels were not significantly different. These results confirm that the brain AA cascade is disturbed in BD, and that certain enzymes associated with AA release from membrane phospholipid and with its downstream metabolism are upregulated. As mood stabilizers downregulate many of these brain enzymes in animal models, their clinical efficacy may depend on suppressing a pathologically upregulated cascade in BD. An upregulated cascade should be considered as a target for drug development and for neuroimaging in BD.

Do omega-6 and trans fatty acids play a role in complex regional pain syndrome? A pilot study

OBJECTIVES

The study aims to compare the omega-6 (n-6) and omega-3 (n-3) highly unsaturated fatty acids (HUFA), and trans fatty acid (trans FA) status of Complex Regional Pain Syndrome (CRPS) patients to pain-free controls.

DESIGN

Case control study. Setting. The setting was at a multidisciplinary rehabilitation center.

PATIENTS

Twenty patients that met the Budapest research diagnostic criteria for CRPS and 15 pain-free control subjects were included in this study. Outcome Measures. Fasting plasma fatty acids were collected from all participants. In CRPS patients, pain was assessed using the McGill Pain Questionnaire-Short Form. In addition, results from the perceived disability (Pain Disability Index), pain-related anxiety (Pain Anxiety Symptom Scale Short Form), depression (Center for Epidemiologic Studies Depression Scale Short Form), and quality of life (Short Form-36 [SF-36]) were evaluated.

RESULTS

Compared with controls, CRPS patients demonstrated elevated concentrations of n-6 HUFA and trans FA. No differences in n-3 HUFA concentrations were observed. Plasma concentrations of the n-6 HUFA docosatetraenoic acid were inversely correlated with the "vitality" section of the SF-36. Trans FA concentrations positively correlated with pain-related disability and anxiety.

CONCLUSION

These pilot data suggest that elevated n-6 HUFA and trans FA may play a role in CRPS pathogenesis. These findings should be replicated, and more research is needed to explore the clinical significance of low n-6 and trans FA diets with or without concurrent n-3 HUFA supplementation, for the management of CRPS.

Increased oxidative stress in healthy children following an exercise program: a pilot study

Exercise can induce oxidative stress or an imbalance between reactive oxygen species and cellular antioxidant defenses.

OBJECTIVE

We investigated the effect of a real-life exercise program on systemic oxidative stress measured by urinary concentrations of 8-isoprostaglandin F2alpha (8-iso-PGF2 alpha), a noninvasive index of lipid peroxidation, in a well-characterized pediatric group.

METHODS

Healthy but primarily sedentary, 8- to 10-year-old children (n = 6, mean age 8.8 +/- 0.9 years) of equally distributed healthy weight, overweight, and obese categories, participated in a 5-week exercise program (track and field summer camp, 2 hours/day, 1-2 days/week).

RESULTS

By using high-performance liquid chromatography with online electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS), we found a significant (p = .028) increase in group mean urinary 8-iso-PGF2 alpha concentration from 8.163 +/- 6.919 ng/mg creatinine pre-exercise program to 32.320 +/- 16.970 ng/mg creatinine post-exercise program. The increase was also measured at each individual level. We found preliminary evidence that pre- and post-exercise program urinary 8-iso-PGF2 alpha concentrations selectively correlated with children's cardiometabolic characteristics and mood.

CONCLUSION

Our results warrant further exploration of the relationships between pre/post-exercise oxidative stress marker 8-iso-PGF2 alpha and cardiometabolic characteristics, exercise habits, eating habits, and mood to determine whether increased post-exercise oxidative stress in healthy children is part of their normal adaptation to exercise or mediator of oxidative injury.

Brain lipid concentrations in bipolar disorder

Reduced concentrations of docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) have been reported in the postmortem bipolar disorder (BD) brain. Additionally, an increased prevalence of BD has been related to low dietary intake of fish, and dietary supplements containing fish products or DHA have been reported to ameliorate BD symptoms. These observations suggest that brain lipid metabolism, particularly involving DHA, is disturbed in BD. To test this suggestion, concentrations of different lipids were measured using internal standards in postmortem frontal cortex from eight BD patients and six matched controls. Compared with control cortex, the BD cortex showed no statistically significant difference in mean concentrations (per gram wet weight) of "stable" lipids (total lipid, total phospholipid, individual phospholipids, or cholesterol), of unesterified fatty acids, or of esterified DHA or AA within stable lipids. Fractional esterified AA and DHA concentrations also did not differ significantly between groups. Some fatty acid concentration differences were found in low-abundant cholesteryl ester. These results do not support the hypothesis of disturbed brain lipid concentrations, including concentrations of AA and DHA, in BD. Positron emission tomography might be used, however, to see if brain AA or DHA kinetics are disturbed in the disease.

Mode of action of mood stabilizers: is the arachidonic acid cascade a common target?

Bipolar disorder is a major medical, social and economic burden worldwide. However, the mechanisms of action of effective antibipolar disorder drugs remain elusive. In this paper, we review studies using a neuropharmacological approach in unanesthetized rats, combined with kinetic, biochemical and molecular biology techniques, showing that chronic administration of three Food and Drug Administration-approved mood stabilizers (lithium, valproate and carbamazepine) at therapeutically relevant doses, selectively target the brain arachidonic acid (AA) cascade. Whereas chronic lithium and carbamazepine decrease the binding activity of activator protein-2 and in turn the transcription, translation and activity of its AA-selective calcium-dependent phospholipase A(2) gene product, valproate appears to be a non-competitive inhibitor of long-chain acyl-CoA synthetase. The net overlapping effects of the three drugs are decreased turnover of AA but not of docosahexaenoic acid in rat brain phospholipids, and decreased brain cyclooxygenase-2 and prostaglandin E(2). Although these observations support the hypothesis proposed by Rapoport and colleagues that the AA cascade is a common target of mood stabilizers, this hypothesis is not necessarily exclusive of other targets. Targeting the AA cascade with drugs or diet may be a useful therapeutic approach in bipolar disorder, and examining the AA cascade in patients might help in better understanding the disease.

Synergistic effects of stress and omega-3 fatty acid deprivation on emotional response and brain lipid composition in adult rats

The aim was to determine the consequences of multi-generational n-3 polyunsaturated fatty acids (PUFA) deficiency on emotional response in rats subjected to maternal separation (MS) as chronic early life stress. Pups fed a control or an n-3 PUFA deficient diet were daily separated for 2 weeks before weaning. In adult rats, reward response was assessed by sucrose consumption and reactivity to novelty using openfield test. Both n-3 PUFA deficiency and MS increased reward response and impulsivity. Moreover, nutritional deficiency and stress acted in synergy to elevate sucrose intake by 80%, compared to control conditions. n-3 PUFA deprivation induced a depletion of docosahexanoeic acid of brain membranes by 70% compensated by increase in 22:5 n-6 and arachidonic acid (AA) levels. The diet-induced AA increase was, however, significantly higher in MS rats. This suggests that n-3 PUFA deficit could be an environmental risk increasing vulnerability to depressive-like response induced by chronic stress.

BanI polymorphism of cytosolic phospholipase A2 gene is associated with age at onset in male patients with schizophrenia and schizoaffective disorder

The enzymes phospholipases A2 are believed to be involved in the pathology of schizophrenia. We investigated allelic and genotype frequencies of PLA2G4A BanI polymorphism and the rs4375 in PLA2G6A in Croatian schizophrenic patients (n=81) and controls (n=182), using PCR/RFLP. Genotype and allelic frequencies of both loci, alone or in combination did not show significant difference (chi2-test). Allele-wise and genotype-wise meta-analyses of BanI polymorphism in case-control and family-based studies also revealed no significant association with schizophrenia. Multiple logistic regression analyses revealed statistically significant association between several items from PANSS general psychopathology scale and BanI polymorphism in PLA2G4A. BanI polymorphism further showed a significant impact on mean age of the onset of disease in males (betaA1=0.351, P=0.021; Spearman's rA1=0.391, P=0.010) indicating lower mean age at admission in homozygous A2A2 males.

Comparison of therapeutic effects of omega-3 fatty acid eicosapentaenoic acid and fluoxetine, separately and in combination, in major depressive disorder

OBJECTIVE

To compare therapeutic effects of eicosapentaenoic acid (EPA), fluoxetine and a combination of them in major depression.

METHOD

Sixty outpatients with a diagnosis of major depressive disorder based on DSM-IV criteria and a score >or=15 in the 17-item Hamilton Depression Rating Scale (HDRS) were randomly allocated to receive daily either 1000 mg EPA or 20 mg fluoxetine, or their combination for 8 weeks. Double dummy technique was used to double blind the study. Patients were assessed at 2 week intervals. Change in HDRS was the primary outcome measure.

RESULTS

Analysis of covariance for HDRS at week 8 across treatment groups was performed in 48 patients who completed at least 4 weeks of the study, with the last observation carried forward. Treatment, age of onset and baseline HDRS had a significant effect on HDRS at week 8. EPA + fluoxetine combination was significantly better than fluoxetine or EPA alone from the fourth week of treatment. Fluoxetine and EPA appear to be equally effective in controlling depressive symptoms. Response rates (>or=50% decrease in baseline HDRS) were 50%, 56% and 81% in the fluoxetine, EPA and combination groups, respectively.

CONCLUSIONS

In the present 8 week trial EPA and fluoxetine had equal therapeutic effects in major depressive disorder. EPA + fluoxetine combination was superior to either of them alone.

Chronic N-methyl-D-aspartate administration increases the turnover of arachidonic acid within brain phospholipids of the unanesthetized rat

Whereas antibipolar drug administration to rats reduces brain arachidonic acid turnover, excessive N-methyl-d-aspartate (NMDA) signaling is thought to contribute to bipolar disorder symptoms and may increase arachidonic acid turnover in rat brain phospholipids. To determine whether chronic NMDA would increase brain arachidonic acid turnover, rats were daily administered NMDA (25 mg/kg, ip) or vehicle for 21 days. In unanesthetized rats, on day 21, [1-(14)C]arachidonic acid was infused intravenously and arterial blood plasma was sampled until the animal was euthanized at 5 min and its microwaved brain was subjected to chemical and radiotracer analysis. Using equations from our in vivo fatty acid model, we found that compared with controls, chronic NMDA increased the net rate of incorporation of plasma unesterified arachidonic acid into brain phospholipids (25-34%) as well as the turnover of arachidonic acid within brain phospholipids (35-58%). These changes were absent at 3 h after a single NMDA injection. The changes, opposite to those after chronic administration of antimanic drugs to rats, suggest that excessive NMDA signaling via arachidonic acid may be a model of upregulated arachidonic acid turnover in brain phospholipids.

Chronic NMDA administration to rats up-regulates frontal cortex cytosolic phospholipase A2 and its transcription factor, activator protein-2

Excessive N-methyl-D-aspartate (NMDA) signaling is thought to contribute to bipolar disorder symptoms. Lithium and carbamazepine, effective against bipolar mania, are reported in rats to reduce brain transcription of an arachidonic acid selective calcium-dependent cytosolic phospholipase A(2) (cPLA(2)), as well as expression of one of its transcription factors, activator protein (AP)-2. In this study, we determined if chronic administration of NMDA (25 mg/kg i.p.) to rats would increase brain cPLA(2) and AP-2 expression, as these antimanic drugs are known to down-regulate excessive NMDA signaling. Administration of a daily subconvulsive dose of NMDA to rats for 21 days decreased frontal cortex NMDA receptor (NR)-1 and NR-3A subunits and increased cPLA(2) activity, phosphorylation, protein, and mRNA levels. The activity and protein levels of secretory phospholipase A(2) or calcium-independent phospholipase A(2) were not changed significantly. Chronic NMDA also increased the DNA-binding activity of AP-2 and the protein levels of its alpha and beta subunits. These changes were absent following acute (3 h earlier) NMDA administration. The changes, opposite to those found following chronic lithium or carbamazepine, are consistent with up-regulated arachidonic acid release due to excessive NR signaling and may be a contributing factor to bipolar mania.

Arachidonic acid metabolism in brain physiology and pathology: lessons from genetically altered mouse models

The arachidonic acid (AA) cascade involves the release of AA from the membrane phospholipids by a phospholipase A(2), followed by its subsequent metabolism to bioactive prostanoids by cyclooxygenases coupled with terminal synthases. Altered brain AA metabolism has been implicated in neurological, neurodegenerative, and psychiatric disorders. The development of genetically altered mice lacking specific enzymes of the AA cascade has helped to elucidate the individual roles of these enzymes in brain physiology and pathology. The roles of AA and its metabolites in brain physiology, with a particular emphasis on the phospholipase A(2)/cyclooxygenases pathway, are summarized, and the specific phenotypes of genetically altered mice relevant to brain physiology and neurotoxic models are discussed.

Dual inhibition of cyclooxygenase and lipoxygenase enzymes by human cerebrospinal fluid

Thromboxane A2 (TXA2) formed in damaged brain tissue and after thromboembolism and subarachnoid haemorrhage is responsible for cerebral vasospasm. In the present study, we examined the effect of human cerebrospinal fluid (CSF) on the production of thromboxane-A2 (TXA2) and 12-hydroxy-eicosatetraenoic acid (12-HETE) by human blood platelets. CSF was drawn by lumbar puncture from normal healthy volunteers (n = 17) and samples judged to be normal after routine examination in the clinical laboratories and were used fresh. We found that CSF inhibited the production of TXA2 and 12-HETE by blood platelets incubated with C14 labelled arachidonic acid (AA) in a concentration-related manner. Further biochemical analysis using proteolytic enzymes, gel filtration and membrane partition chromatography showed that the inhibitory activity was peptidic in nature and associated with a peptide of low molecular weight (1,400 Da). This study is the first to demonstrate that human CSF contains a dual inhibitor of cyclooxygenase (COX) and lipoxygenase enzymes in CSF.

Omega-3 fatty acid supplementation in patients with recurrent self-harm. Single-centre double-blind randomised controlled trial

BACKGROUND

Trials have demonstrated benefits of long-chain omega-3 essential fatty acid (n-3 EFA) supplementation in a variety of psychiatric disorders.

AIMS

To assess the efficacy of n-3 EFAs in improving psychological well-being in patients with recurrent self-harm.

METHOD

Patients (n=49) presenting after an act of repeated self-harm were randomised to receive 1.2 g eicosapentaenoic acid plus 0.9 g decosahexaenoic acid (n=22) or placebo (n=27) for 12 weeks in addition to standard psychiatric care. Six psychological domains were measured at baseline and end point.

RESULTS

At 12 weeks, the n-3 EFA group had significantly greater improvements in scores for depression, suicidality and daily stresses. Scores for impulsivity, aggression and hostility did not differ.

CONCLUSIONS

Supplementation achieved substantial reductions in surrogate markers of suicidal behaviour and improvements in well-being. Larger studies are warranted to determine if insufficient dietary intake of n-3 EFAs is a reversible risk factor for self-harm.

Chronic fluoxetine upregulates arachidonic acid incorporation into the brain of unanesthetized rats

Serotonergic 5-HT(2A/2C) receptors can be coupled to phospholipase A(2) (PLA(2)) activation to release the second messenger, arachidonic acid (AA), from membrane phospholipids. We wished to see if this signaling process in rat brain would be altered by chronic administration followed by 3days of washout of the selective serotonin reuptake inhibitor, fluoxetine. We injected [(3)H]AA intravenously in unanesthetized rats and used quantitative autoradiography to determine the incorporation coefficient k() for AA (regional brain radioactivity/integrated plasma radioactivity), a marker of PLA(2) activation, in each of 86 brain regions. k() was measured following acute i.p. saline or (+/-)-2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI, 1.0mg/kg i.p.), a 5-HT(2A/2C) receptor agonist, in rats injected for 21days with 10mg/kg i.p. fluoxetine or saline daily, followed by 3days without injection. Acute DOI produced statistically significant increments in k() in brain regions with high densities of 5-HT(2A/2C) receptors, but the increments did not differ significantly between the chronic fluoxetine- and saline-treated rats. Additionally, chronic fluoxetine compared with saline widely and significantly increased baseline values of k(). These results suggest that 5-HT(2A/2C) receptor-initiated AA signaling is unaffected by chronic fluoxetine plus 3days of washout in the rat, but that baseline AA signaling is nevertheless upregulated. This upregulation likely occurs independently of significant active drug in brain, considering the short brain half-lives of it and its norfluoxetine metabolite. Such upregulation may contribute to fluoxetine's efficacy against human depression.

Cytosolic prostaglandin E2 synthase (cPGES) expression is decreased in discrete cortical regions in psychiatric disease

The number of adults in the US affected by bipolar disorder, depression, or schizophrenia is approaching 15 million. Despite decades of research, etiologies of these illnesses remain elusive. Theories of aberrant brain morphology, neurotransmission, and signal conduction have provided the heuristic framework for a large body of literature, with attention focused upon hypotheses of monoamine signaling underlying psychiatric disease. More recently, attention has turned to potential contributions of other signaling pathways, including the arachidonic acid cascade and generation of prostaglandins (PG). To determine the potential involvement of the pathways leading to PGE2 synthesis in psychiatric disease, immunohistochemistry and immunoblotting were performed to measure regional expression of the cyclooxygenases (COX) and one of the terminal PGE2 synthases (PGES) in postmortem tissue provided by The Stanley Medical Research Institute. For normal, bipolar, depressed, and schizophrenic subjects, COX-1 and COX-2 protein levels did not differ across region and patient populations. In contrast, there was a significant effect of diagnosis on cytosolic PGES (cPGES) protein levels in the frontal cortex, with remarkable decreases observed in all psychiatric groups relative to normal tissue (P < 0.05). Significant reduction of cPGES expression was also found in the temporal cortex of bipolar subjects. Evaluation of medicated vs. non-medicated subjects revealed a significant effect of medication on cPGES expression in the frontal cortex of bipolar, but not depressed or schizophrenic subjects. These novel findings further support hypotheses of abnormalities in fatty acid and phospholipid metabolism in regions associated with psychiatric disease.

Cyclooxygenase-1 and -2 enzymes differentially regulate the brain upstream NF-kappa B pathway and downstream enzymes involved in prostaglandin biosynthesis

We have recently reported that cyclooxygenase (COX)-2-deficiency affects brain upstream and downstream enzymes in the arachidonic acid (AA) metabolic pathway to prostaglandin E2 (PGE2), as well as enzyme activity, protein and mRNA levels of the reciprocal isozyme, COX-1. To gain a better insight into the specific roles of COX isoforms and characterize the interactions between upstream and downstream enzymes in brain AA cascade, we examined the expression and activity of COX-2 and phospholipase A2 enzymes (cPLA2 and sPLA2), as well as the expression of terminal prostaglandin E synthases (cPGES, mPGES-1, and - 2) in wild type and COX-1(-/-) mice. We found that brain PGE2 concentration was significantly increased, whereas thromboxane B2 (TXB2) concentration was decreased in COX-1(-/-) mice. There was a compensatory up-regulation of COX-2, accompanied by the activation of the NF-kappaB pathway, and also an increase in the upstream cPLA2 and sPLA2 enzymes. The mechanism of NF-kappaB activation in the COX-1(-/-) mice involved the up-regulation of protein expression of the p50 and p65 subunits of NF-kappaB, as well as the increased protein levels of phosphorylated IkappaBalpha and of phosphorylated IKKalpha/beta. Overall, our data suggest that COX-1 and COX-2 play a distinct role in brain PG biosynthesis, with basal PGE2 production being metabolically coupled with COX-2 and TXB2 production being preferentially linked to COX-1. Additionally, COX-1 deficiency can affect the expression of reciprocal and coupled enzymes, COX-2, Ca2+ -dependent PLA2, and terminal mPGES-2, to overcome defects in brain AA cascade.

Omega-3 polyunsaturated fatty acids and depression: a review of the evidence and a methodological critique

Several lines of evidence indicate an association between omega-3 polyunsaturated fatty acids (PUFAs) and depression. The purpose of this review was to evaluate the evidence to date within the context of the study design and methodology used. In case-control and cohort studies, concentrations of omega-3 PUFAs were lower in participants with unipolar and postpartum depression. Fish are the major dietary source of omega-3 PUFAs, and infrequent fish consumption is associated with depression in epidemiological studies. While these findings do not appear to be the result of confounding, in some studies failure to detect confounding may be due to a lack of power or incomplete control. In four of seven double-blind randomized controlled trials, depression was significantly improved upon treatment with at least 1 g/day of eicosapentaenoic acid, an omega-3 PUFA. While clinical significance was demonstrated, preservation of blinding may be a limitation in this area of research. It remains unclear whether omega-3 supplementation is effective independently of antidepressant treatment, for depressed patients in general or only those with abnormally low concentrations of these PUFAs. The relationship between omega-3 PUFAs and depression is biologically plausible and is consistent across study designs, study groups, and diverse populations, which increases the likelihood of a causal relationship.

Probing for affective side effects of drugs used in geriatric practice: use of daily diaries to test for effects of metoclopramide and naproxen

The aim of this study was to develop the use of daily diaries of affects and events as measures of pharmacological effects on affective processes and to apply them to evaluate the possible affective toxicity of metoclopramide and naproxen, two medications commonly used in geriatric practice. In all, 105 adults aged 65 years or older were randomized to receive metoclopramide (up to 40 mg/day), naproxen (up to 1000 mg/day), or placebo under double-blind conditions for a period of 5 weeks. Patients were seen weekly for evaluations of affective and cognitive outcomes as well as safety. In addition, patients kept diaries with daily records of positive and negative affect and reports of significant daily events. Findings included mixed model analyses of drug assignment, time, events, and interactions for both positive affect and days with significant negative affect. Subjects exhibited high levels of adherence in completing daily diaries. Neither the pattern of dropouts nor the weekly assessments demonstrated significant drug effects on mood or affect. However, diary data demonstrated that metoclopramide increased the apparent impact of negative events on both positive and negative affect relative to placebo, and that naproxen increased the apparent impact of positive events on positive affect and, possibly, of negative events on negative affect relative to placebo. The findings confirm the utility of diary methods for studying drug effects on affective processes in normal elderly subjects. They suggest that both metoclopramide and naproxen can affect the associations between daily events and affects. If replicated, they would demonstrate that drug effects can extend beyond the intensity of affect and/or the emergence of full-fledged psychiatric disorders to include moderation of the interactions between daily events and affect.