The membrane phospholipid hypothesis as a biochemical basis for the neurodevelopmental concept of schizophrenia

Potential metabolite markers of schizophrenia

Schizophrenia is a severe mental disorder that affects 0.5-1% of the population worldwide. Current diagnostic methods are based on psychiatric interviews, which are subjective in nature. The lack of disease biomarkers to support objective laboratory tests has been a long-standing bottleneck in the clinical diagnosis and evaluation of schizophrenia. Here we report a global metabolic profiling study involving 112 schizophrenic patients and 110 healthy subjects, who were divided into a training set and a test set, designed to identify metabolite markers. A panel of serum markers consisting of glycerate, eicosenoic acid, β-hydroxybutyrate, pyruvate and cystine was identified as an effective diagnostic tool, achieving an area under the receiver operating characteristic curve (AUC) of 0.945 in the training samples (62 patients and 62 controls) and 0.895 in the test samples (50 patients and 48 controls). Furthermore, a composite panel by the addition of urine β-hydroxybutyrate to the serum panel achieved a more satisfactory accuracy, which reached an AUC of 1 in both the training set and the test set. Multiple fatty acids and ketone bodies were found significantly (P<0.01) elevated in both the serum and urine of patients, suggesting an upregulated fatty acid catabolism, presumably resulting from an insufficiency of glucose supply in the brains of schizophrenia patients.

Effects of omega-3 dietary supplement in prevention of positive, negative and cognitive symptoms: a study in adolescent rats with ketamine-induced model of schizophrenia

Omega-3 has shown efficacy to prevent schizophrenia conversion in ultra-high risk population. We evaluated the efficacy of omega-3 in preventing ketamine-induced effects in an animal model of schizophrenia and its effect on brain-derived neurotrophic factor (BDNF). Omega-3 or vehicle was administered in Wistar male rats, both groups at the 30th day of life for 15days. Each group was split in two to receive along the following 7days ketamine or saline. Locomotor and exploratory activities, memory test and social interaction between pairs were evaluated at the 52nd day of life. Prefrontal-cortex, hippocampus and striatum tissues were extracted right after behavioral tasks for mRNA BDNF expression analysis. Bloods for serum BDNF were withdrawn 24h after the end of behavioral tasks. Locomotive was increased in ketamine-treated group compared to control, omega-3 and ketamine plus omega-3 groups. Ketamine group had fewer contacts and interaction compared to other groups. Working memory and short and long-term memories were significantly impaired in ketamine group compared to others. Serum BDNF levels were significantly higher in ketamine plus omega-3 group. There was no difference between groups in prefrontal-cortex, hippocampus and striatum for mRNA BDNF expression. Administration of omega-3 in adolescent rats prevents positive, negative and cognitive symptoms in a ketamine animal model of schizophrenia. Whether these findings are consequence of BDNF increase it is unclear. However, this study gives compelling evidence for larger clinical trials to confirm the use of omega-3 to prevent schizophrenia and for studies to reinforce the beneficial role of omega-3 in brain protection.

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.

The reduction of superoxide dismutase activity is associated with the severity of neurological soft signs in patients with schizophrenia

This study aimed to explore the relationship between antioxidant enzyme activities and neurological soft signs (NSS) in a sample of patients with schizophrenia. Sixty clinically stable patients with schizophrenia treated mostly by first-generation antipsychotics and 30 matched healthy controls were recruited. NSS were assessed in two groups by a standardized neurological examination (Krebs et al., 2000). The red blood cell (RBC) antioxidant activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were measured by spectrophotometry. RBC activities of all enzymes studied: SOD, GSH-Px and CAT, were significantly lower in the patients compared to control group. All NSS scores were significantly higher in the patients compared to healthy controls' scores. In the patients, a negative correlation was found between RBC SOD activity and NSS total score and motor coordination and motor integration sub-scores. The association between low SOD activity as a marker of oxidative stress and NSS in schizophrenic patients suggests a common pathological process of these abnormalities.

Impaired plasmalogens in patients with schizophrenia

Plasmalogens are a subclass of glycerophospholipids and ubiquitous constituents of cellular membranes and serum lipoproteins. Several neurological disorders show decreased level of plasmogens. An earlier study found differences in plasma phospholipids between unmedicated patients with schizophrenia and matched healthy control subjects. We here report a comparison of plasma plasmalogen levels across 20 drug-naïve patients experiencing first psychotic episodes, 20 recently unmedicated patients experiencing psychotic relapses after failing to comply with prescribed medications, and 17 matched healthy control subjects. Multiple plasma phosphatidylcholine and phosphatidylethanolamine plasmalogen levels were significantly lower in first episode patients and patients with recurrent disease compared to healthy controls. Reduced plasmalogen levels appear to be a trait evident at the onset of psychotic illness and after multiple psychotic relapses. It is implied that reductions in plasmalogen levels are not related to antipsychotic treatment but due to the illness itself. Reduced plasmalogen levels suggest impairments in membrane structure and function in patients with schizophrenia that might happen early in development. This may serve as a clue to the neurobiology of schizophrenia and should be studied as a potential biomarker for individuals at risk for schizophrenia.

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.

Clozapine resistance: augmentation strategies

BACKGROUND

Clozapine (CLZ) is not effective in more than 50% of treatment-resistant schizophrenic patients. In these cases, several pharmacological strategies are used in clinical practice, with different levels of evidence for both safety and efficacy.

OBJECTIVES

In the present paper we critically reviewed literature data regarding the efficacy and safety of adjunctive agents in CLZ-resistant schizophrenics. The following classes of agents were considered: 1) antipsychotics, 2) antidepressants, 3) mood stabilizers, 4) other agents (e.g. fatty acid supplement and glutamatergic agents), 5) electroconvulsive therapy (ECT). For lamotrigine and risperidone sufficient data were available to perform a meta-analysis.

METHODS

A Medline literature search covering a 20-year period was performed. For the meta-analysis, data were entered and analyzed with the Cochrane Collaboration Review Manager Software (RevMan version 5).

RESULTS

62 pertinent studies were identified, including 1556 schizophrenic or schizoaffective patients. Among treatments investigated, there is evidence for CLZ augmentation with 1) amisulpride and aripiprazole, 2) mirtazapine and 3) ethyl eicosapentaenoic acid (E-EPA). Although promising, ECT augmentation needs further validation. The meta-analyses did not support either the use of risperidone or lamotrigine as CLZ adjunct.

CONCLUSION

Overall, there is scarce evidence of efficacy and safety as regards adjunctive strategies for CLZ-resistant patients. However, several limitations do not allow to draw any definitive conclusion; among these we underline the small sample size of clinical trials, the variable definitions of CLZ resistance, the heterogeneity of outcome measures and methodological designs.

Phospholipids and insulin resistance in psychosis: a lipidomics study of twin pairs discordant for schizophrenia

BACKGROUND

Several theories have been proposed to conceptualize the pathological processes inherent to schizophrenia. The 'prostaglandin deficiency' hypothesis postulates that defective enzyme systems converting essential fatty acids to prostaglandins lead to diminished levels of prostaglandins, which in turn affect synaptic transmission.

METHODS

Here we sought to determine the lipidomic profiles associated with schizophrenia in twin pairs discordant for schizophrenia as well as unaffected twin pairs. The study included serum samples from 19 twin pairs discordant for schizophrenia (mean age 51 ± 10 years; 7 monozygotic pairs; 13 female pairs) and 34 age and gender matched healthy twins as controls. Neurocognitive assessment data and gray matter density measurements taken from high-resolution magnetic resonance images were also obtained. A lipidomics platform using ultra performance liquid chromatography coupled to time-of-flight mass spectrometry was applied for the analysis of serum samples.

RESULTS

In comparison to their healthy co-twins, the patients had elevated triglycerides and were more insulin resistant. They had diminished lysophosphatidylcholine levels, which associated with decreased cognitive speed.

CONCLUSIONS

Our findings may be of pathophysiological relevance since lysophosphatidylcholines, byproducts of phospholipase A2-catalyzed phospholipid hydrolysis, are preferred carriers of polyunsaturated fatty acids across the blood-brain barrier. Furthermore, diminishment of lysophosphatidylcholines suggests that subjects at risk of schizophrenia may be more susceptible to infections. Their association with cognitive speed supports the view that altered neurotransmission in schizophrenia may be in part mediated by reactive lipids such as prostaglandins.

A structure-function mechanism for schizophrenia

THE MULTIPLE ETIOLOGIES OF SCHIZOPHRENIA PROMPT US TO RAISE THE QUESTION: what final common pathway can induce a convincing sense of the reality of the hallucinations in this disease? The observation that artificial stimulation of an intermediate order of neurons of a normal nervous system induces hallucinations indicates that the lateral entry of activity (not resulting from canonical synaptic transmission) at intermediate neuronal orders may provide a mechanism for hallucinations. Meaningful hallucinations can be de-constructed into an organized temporal sequence of internal sensations of associatively learned items that occur in the absence of any external stimuli. We hypothesize that these hallucinations are autonomously generated by the re-activation of pathological non-specific functional LINKs formed between the postsynaptic membranes at certain neuronal orders and are examined as a final common mechanism capable of explaining most of the features of the disease. Reversible and stabilizable hemi-fusion between simultaneously activated adjacent postsynaptic membranes is viewed as one of the normal mechanisms for functional LINK formation and is dependent on lipid membrane composition. Methods of removing the proteins that may traverse the non-specifically hemi-fused membrane segments and attempts to replace the phospholipid side chains to convert the membrane composition to a near-normal state may offer therapeutic opportunities.

The role of energy metabolism dysfunction and oxidative stress in schizophrenia revealed by proteomics

Schizophrenia is a psychiatric illness that affects approximately 30 million people worldwide. Converging lines of evidence suggest that mitochondrial function may be compromised in this disorder, and this can lead to perturbations in calcium buffering, oxidative phosphorylation, increased production of reactive oxygen species, and apoptotic factors, which can, in turn, affect neuronal processes such as neurotransmitter synthesis and synaptic plasticity. Proteomics studies in brain and peripheral tissues of schizophrenia patients have provided considerable evidence and identified biomarker fingerprints corresponding to such pathways. Here we review the results of these studies with a focus on the biomarker pattern depicting alterations in energy metabolism and oxidative stress in this debilitating illness.

Antioxidants, redox signaling, and pathophysiology in schizophrenia: an integrative view

Schizophrenia (SZ) is a brain disorder that has been intensively studied for over a century; yet, its etiology and multifactorial pathophysiology remain a puzzle. However, significant advances have been made in identifying numerous abnormalities in key biochemical systems. One among these is the antioxidant defense system (AODS) and redox signaling. This review summarizes the findings to date in human studies. The evidence can be broadly clustered into three major themes: perturbations in AODS, relationships between AODS alterations and other systems (i.e., membrane structure, immune function, and neurotransmission), and clinical implications. These domains of AODS have been examined in samples from both the central nervous system and peripheral tissues. Findings in patients with SZ include decreased nonenzymatic antioxidants, increased lipid peroxides and nitric oxides, and homeostatic imbalance of purine catabolism. Reductions of plasma antioxidant capacity are seen in patients with chronic illness as well as early in the course of SZ. Notably, these data indicate that many AODS alterations are independent of treatment effects. Moreover, there is burgeoning evidence indicating a link among oxidative stress, membrane defects, immune dysfunction, and multineurotransmitter pathologies in SZ. Finally, the body of evidence reviewed herein provides a theoretical rationale for the development of novel treatment approaches.

Altered tryptophan and alanine transport in fibroblasts from boys with attention-deficit/hyperactivity disorder (ADHD): an in vitro study

Background

The catecholaminergic and serotonergic neurotransmitter systems are implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). The amino acid tyrosine is the precursor for synthesis of the catecholamines dopamine and norepinephrine, while tryptophan is the precursor of serotonin. A disturbed transport of tyrosine, as well as other amino acids, has been found in a number of other psychiatric disorders, such as schizophrenia, bipolar disorder and autism, when using the fibroblast cell model. Hence, the aim of this study was to explore whether children with ADHD may have disturbed amino acid transport.

Methods

Fibroblast cells were cultured from skin biopsies obtained from 14 boys diagnosed with ADHD and from 13 matching boys without a diagnosis of a developmental disorder. Transport of the amino acids tyrosine, tryptophan and alanine across the cell membrane was measured by the cluster tray method. The kinetic parameters, maximal transport capacity (V_max) and affinity constant (K_m) were determined. Any difference between the two groups was analyzed by Student's unpaired t-test or the Mann Whitney U test.

Results

The ADHD group had significantly decreased V_max (p = 0.039) and K_m (increased affinity) (p = 0.010) of tryptophan transport in comparison to controls. They also had a significantly higher V_maxof alanine transport (p = 0.031), but the Km of alanine transport did not differ significantly. There were no significant differences in any of the kinetic parameters regarding tyrosine transport in fibroblasts for the ADHD group.

Conclusions

Tryptophan uses the same transport systems in both fibroblasts and at the blood brain barrier (BBB). Hence, a decreased transport capacity of tryptophan implies that less tryptophan is being transported across the BBB in the ADHD group. This could lead to deficient serotonin access in the brain that might cause disturbances in both the serotonergic and the catecholaminergic neurotransmitter systems, since these systems are highly interconnected. The physiological importance of an elevated transport capacity of alanine to the brain is not known to date.

Quetiapine, olanzapine and haloperidol affect human plasma lipid peroxidation in vitro

OBJECTIVE

Oxidative injury in schizophrenia may be caused not only by pathophysiological processes but partly also by treatment with antipsychotics. The purpose of the present study was to examine and to compare the effects of quetiapine (QUE), olanzapine (OLA) and haloperidol (HAL), at final concentrations corresponding to doses used for treatment of acute episodes of schizophrenia, on plasma lipid peroxidation in vitro, measured by the level of thiobarbituric acid-reactive substances (TBARS).

METHODS

Blood from 30 healthy volunteers was collected into ACD (citric acid/citrate/dextrose) solution. The drugs in form of active substances were dissolved in 0.01% dimethyl sulfoxide, added to plasma at the final concentrations [QUE (175 and 275 ng/ml), OLA (20 and 40 ng/ml), HAL (4 and 20 ng/ml)] and incubated for 1 and 24 h at 37 °C. The level of TBARS was measured spectrophotometrically (according to the Rice-Evans method, 1991).

RESULTS

The comparative study in vitro showed that QUE causes a decrease in the TBARS level in plasma, whereas HAL increases the plasma TBARS level. After 24 h of incubation of plasma with QUE or HAL (at lower and higher concentrations),thedifferences in TBARS levels between the drugs were significant (p = 5.9 × 10⁻⁴, p = 2.2 × 10⁻⁵, respectively).

CONCLUSION

QUE and OLA, contrary to the prooxidative action of HAL, did not induce oxidative stress; moreover, QUE has antioxidant properties.

Polyunsaturated fatty acids in various macroalgal species from North Atlantic and tropical seas

BACKGROUND

In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental disorders, was investigated.

METHODS

The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species.

RESULTS

Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed.

CONCLUSION

Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.

Integrated genetic and genomic approach in the SingaporeTranslational and Clinical Research in Psychosis Study: an overview

AIMS

Schizophrenia is a severe mental disorder with onset frequently in adolescence and followed by a chronic and disabling course. Although the exact pathophysiology of this devastating disorder has not been clearly elucidated, a large part of it has been attributed to genetic influences. This article seeks to provide an overview on what our group has embarked on--to elucidate genetic risk factors for schizophrenia within the Chinese ethnic group.

METHODS

We plan to conduct an integrated approach to interrogate comprehensively the genome from different angles and in stages. The first stage involves a genome-wide association study of 1000 cases of schizophrenia-control pairs, with a follow-up replication study in another 1000 cases of schizophrenia and in 1000 controls, and combination analyses with groups from other places including China and Hong Kong. Other than the genome-wide association study, gene sequencing for purported candidate genes and copy number variation analysis will be performed. Neurocognitive intermediate phenotypes will be employed to deconstruct the complex schizophrenia phenotype in a bid to improve association findings. Promising leads from longitudinal gene and protein expression in ultra-high-risk subjects who develop psychosis and schizophrenia (in a parallel study) will be followed up as candidate genes and sequenced in the genetic analysis. Functional analysis forms the last stage of this integrated approach.

CONCLUSION

This integrated genetic and genomic approach will hopefully help in further characterizing and deepening our understanding of molecular pathophysiological mechanisms underlying schizophrenia.

Impaired plasma phospholipids and relative amounts of essential polyunsaturated fatty acids in autistic patients from Saudi Arabia

Backgrounds

Autism is a developmental disorder characterized by social and emotional deficits, language impairments and stereotyped behaviors that manifest in early postnatal life. This study aims to compare the relative concentrations of essential fatty acids (Linoleic and α- linolenic), their long chain polyunsaturated fatty acids and phospholipids in plasma of autistic patients from Saudi Arabia with age-matching controls.

Methods

25 autistic children aged 3-15 years and 16 healthy children as control group were included in this study. Relative concentration of essential fatty acids/long chain polyunsaturated fatty acids and omega-3/omega-6 fatty acid series together with phosphatidylethanolamine, phosphatidylserine and phosphatidylcholine were measured in plasma of both groups.

Results

Remarkable alteration of essential fatty acids/long chain polyunsaturated fatty acids, omeg-3/omega-6 and significant lower levels of phospholipids were reported. Reciever Operating characteristics (ROC) analysis of the measured parameters revealed a satisfactory level of sensitivity and specificity.

Conclusion

Essential fatty acids/long chain polyunsaturated fatty acids and omeg-3/omega-6 ratios, phosphatidylethanolamine, phosphatidylserine and phosphatidylcholine could be used as potential biomarkers that point to specific mechanisms in the development of autism and may help tailor treatment or prevention strategies.

If waking and dreaming consciousness became de-differentiated, would schizophrenia result?

If both waking and dreaming consciousness are functional, their de-differentiation would be doubly detrimental. Differentiation between waking and dreaming is achieved through neuromodulation. During dreaming, without external sensory data and with mesolimbic dopaminergic input, hyper-cholinergic input almost totally suppresses the aminergic system. During waking, with sensory gates open, aminergic modulation inhibits cholinergic and mesocortical dopaminergic suppresses mesolimbic. These neuromodulatory systems are reciprocally interactive and self-organizing. As a consequence of neuromodulatory reciprocity, phenomenologically, the self and the world that appear during dreaming differ from those that emerge during waking. As a result of self-organizing, the self and the world in both states are integrated. Some loss of self-organization would precipitate a degree of de-differentiation between waking and dreaming, resulting in a hybrid state which would be expressed heterogeneously, both neurobiologically and phenomenologically. As a consequence of progressive de-differentiation, certain identifiable psychiatric disorders may emerge. Ultimately, schizophrenia, a disorganized-fragmented self, may result.

Membrane fatty acid levels as a predictor of treatment response in chronic schizophrenia

Abnormal fatty acid composition in neural membranes, that is, the balance between essential polyunsaturated fatty acids (EPUFAs) and saturated fatty acids, has been suggested to be related to the psychotic symptoms and cognitive impairment of schizophrenia. This study was conducted to test the hypothesis that the ability of atypical antipsychotic drugs to ameliorate positive symptoms and cognitive function relevant to daily living would be predicted by baseline EPUFAs concentrations in the erythrocyte membrane in subjects with schizophrenia. A total of 24 actively psychotic patients with schizophrenia participated in the study. After blood drawing, they were treated with olanzapine or perospirone. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for Assessment of Negative symptoms (SANS), as well as the script tasks, a measure of event schema recognition, were administered at baseline and 3months after the start of treatment. Erythrocyte membrane fatty acid levels were analysed using a gas chromatography system. Scores of SAPS and SANS, as well as script task performance, were improved during treatment with either antipsychotic drug. Regression analysis indicates baseline EPUFAs concentrations were positively and negatively related with percent improvement of positive symptoms and script task performance, respectively. The results of this study suggest composition of phospholipids in the erythrocyte membrane provide a feasible marker to predict treatment response in patients with schizophrenia.

Cognition, dopamine and bioactive lipids in schizophrenia

Schizophrenia is a remarkably complex disorder with a multitude of behavioral and biological perturbations. Cognitive deficits are a core feature of this disorder, and involve abnormalities across multiple domains, including memory, attention, and perception. The complexity of this debilitating illness has led to a view that the key to unraveling its pathophysiology lies in deconstructing the clinically-defined syndrome into pathophysiologically distinct intermediate phenotypes. Accumulating evidence suggests that one of these intermediate phenotypes may involve phospholipid signaling abnormalities, particularly in relation to arachidonic acid (AA). Our data show relationships between levels of AA and performance on tests of cognition for schizophrenia patients, with defects in AA signaling associated with deficits in cognition. Moreover, dopamine may moderate these relationships between AA and cognition. Taken together, cognitive deficits, dopaminergic neurotransmission, and bioactive lipids have emerged as related features of schizophrenia. Existing treatment options for cognitive deficits in schizophrenia do not specifically target lipid-derived signaling pathways; understanding these processes could inform efforts to identify novel targets for treatment innovation.

Autistic disorder and phospholipids: A review

Dysregulated phospholipid metabolism has been proposed as an underlying biological component of neurodevelopmental disorders such as autistic disorder (AD) and attention-deficit/hyperactivity disorder (ADHD). This review provides an overview of fatty acid and phospholipid metabolism and evidence for phospholipid dysregulation with reference to the membrane hypothesis of schizophrenia. While there is evidence that phospholipid metabolism is at least impaired in individuals with AD, it has not been established whether phospholipid metabolism is implicated in causal, mechanistic or epiphenomenological models. More research is needed to ascertain whether breastfeeding, and specifically, the administration of colostrum or an adequate substitute can play a preventative role by supplying the neonate with essential fatty acids (EFAs) at a critical juncture in their development. Regarding treatment, further clinical trials of EFA supplementation are essential to determine the efficacy of EFAs in reducing AD symptomatology and whether supplementation can serve as a cost-effective and readily available intervention.

Hyperglycemia magnifies Schwann cell dysfunction and cell death triggered by PA-induced lipotoxicity

Lipid overload resulting in lipotoxicity is prominent in a number of chronic diseases and has been associated with cellular dysfunction and cell death. This study characterizes palmitic acid-induced lipotoxicity (PA-LTx) in Schwann cell cultures grown in normal and high glucose concentrations. The study shows for the first time that Schwann cell (SC) cultures exposed to elevated levels of PA exhibit a dose- and time-dependent loss in cell viability. Hoescht and Annexin V/7AAD staining confirmed cell death through apoptosis and the lipotoxic effect was more dramatic in SC cultures grown under high glucose conditions. The first indication of cellular dysfunction in treated SC cultures was a decrease in Ca(++) levels in the endoplasmic reticulum (ER, [Ca(++)](ER)) observed five minutes following the initial challenge with PA. This decrease in [Ca(++) ](ER) was followed by a significant increase in the expression of ER stress signature genes CHOP, Xbp1 and GRP78. The early ER stress response induced by PA-LTx was followed by a strong mitochondrial membrane depolarization. Flow cytometry using 2', 7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) showed an increase in oxidative stress within three to six hours after PA treatment. Treatment of cultures undergoing PA-LTx with the calcium chelator BAPTA-AM and the anti-oxidant MCI-186 significantly reversed the lipotoxic effect by decreasing the generation of ROS and significantly increasing cell viability. We conclude that lipotoxicity in Schwann cells results in cellular dysfunction and cell death that involves a robust ER stress response, mitochondrial dysfunction and an augmented state of cellular oxidative stress (ASCOS).

Beyond the first episode: candidate factors for a risk prediction model of schizophrenia

Many early psychosis services are financially compromised and cannot offer a full tenure of care to all patients. To maintain viability of services it is important that those with schizophrenia are identified early to maximize long-term outcomes, as are those with better prognoses who can be discharged early. The duration of untreated psychosis remains the mainstay in determining those who will benefit from extended care, yet its ability to inform on prognosis is modest in both the short and medium term. There are a number of known or putative genetic and environmental risk factors that have the potential to improve prognostication, though a multivariate risk prediction model combining them with clinical characteristics has yet to be developed. Candidate risk factors for such a model are presented, with an emphasis on environmental risk factors. More work is needed to corroborate many putative factors and to determine which of the established factors are salient and which are merely proxy measures. Future research should help clarify how gene-environment and environment-environment interactions occur and whether risk factors are dose-dependent, or if they act additively or synergistically, or are redundant in the presence (or absence) of other factors.

Association between polymorphisms of arachidonate 12-lipoxygenase (ALOX12) and schizophrenia in a Korean population

Arachidonic acid (AA), an essential polyunsaturated fatty acid, is one of the major components of neural membranes, which show an altered phospholipid composition in schizophrenia. Arachidonate 12-lipoxygenase (ALOX12), an important enzyme, metabolizes AA to 12-HPETE, which affects catecholamine synthesis. However, research has yet to show the genetic association between ALOX12 and schizophrenia. Therefore, we investigated single nucleotide polymorphisms (SNP) of the ALOX12 gene in schizophrenia, recruiting patients with schizophrenia (n = 289) and normal controls (n = 306) from a Korean population. We selected three SNPs (rs1126667, rs434473, and rs1042357) of the ALOX12 gene and genotyped them by direct sequencing. We reviewed the schizophrenic patients' medical records and assessed them clinically using the Brief Psychiatric Rating Scale (BPRS), the Scale for the Assessment of Negative Symptoms (SANS), and the Operational Criteria Checklist (OPCRIT). Then we statistically analyzed the genetic associations between the SNPs and schizophrenia, finding a genetic association between both rs1126667 and rs1042357 and schizophrenia, in the recessive model (p = 0.015 and 0.015, respectively). We also found an association between rs434473 and negative symptoms, defined through a factor analysis of the OPCRIT data (p = 0.040). Consequently, we suggest that SNPs of the ALOX12 gene might be associated with schizophrenia and negative symptoms in this Korean population. These weak positives require additional study.

The association of fatty acid deficiency symptoms (FADS) with actual essential fatty acid status in cheek cells

Seven clinical symptoms have been utilised in several studies as a means of potentially identifying children with a deficiency in essential polyunsaturated fatty acids (PUFAs). The purpose of this study was to investigate whether there was any correlation between parental reports of the frequency of these seven 'fatty acid deficiency symptoms' (FADS) with actual levels of fatty acids in buccal cell samples of 450 children aged 8-10 years old. Additionally, the relationship between FADS and cognitive test performance, ratings of attention and behaviour and other somatic complaints were explored. The severity of reported FADS was not related to the levels of omega-6 or omega-3 in buccal cell samples. There was a relationship between parental reports of child behaviour and reported FADS; with high FADS being related to higher ratings of behaviour problems. Using FADS as a marker of PUFA deficiency may not be appropriate especially when assessing typically developing children.

Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33,000 women from the general population

BACKGROUND

Low intake of fish, polyunsaturated fatty acids (PUFA) and vitamin D deficiency has been suggested to play a role in the development of schizophrenia. Our aim was to evaluate the association between the intake of different fish species, PUFA and vitamin D and the prevalence of psychotic-like symptoms in a population-based study among Swedish women.

METHODS

Dietary intake was estimated using a food frequency questionnaire among 33,623 women aged 30-49 years at enrollment (1991/92). Information on psychotic-like symptoms was derived from a follow-up questionnaire in the years 2002/03. Participants were classified into three predefined levels: low, middle and high frequency of symptoms. The association between diet and psychotic-like symptoms was summarized in terms of relative risks (RR) and corresponding 95% confidence intervals and was evaluated by energy-adjusted multinomial logistic regression.

RESULTS

18,411 women were classified as having a low level of psychotic-like symptoms, 14 395 as middle and 817 as having a high level. The risk of high level symptoms was 53% (95% CI, 30-69%) lower among women who ate fish 3-4 times per week compared to women who never ate fish. The risk was also lower for women with a high intake of omega-3 and omega-6 PUFA compared to women with a lower intake of these fatty acids. The effect was most pronounced for omega-6 PUFAs. The RR comparing the highest to the lowest quartile of omega-6 PUFAs intake was 0.78 (95% CI, 0.64-0.97). The associations were J-shaped with the strongest reduced risk for an intermediate intake of fish or PUFA. For fatty fish (herring/mackerel, salmon-type fish), the strongest inverse association was found for an intermediate intake (RR: 0.81, 95% CI, 0.66-0.98), whereas a high intake of fatty fish was associated with an increased risk of psychotic-like symptoms (RR: 1.90, 95% CI, 1.34-2.70). Women in the highest compared with the lowest quartile of vitamin D consumption experienced a 37% (95% CI, 22-50%) lower risk of psychotic-like symptoms.

CONCLUSION

Our findings raise a possibility that adult women with a high intake of fish, omega-3 or omega-6 PUFA and vitamin D have a lower rate of psychotic-like symptoms.

Study of association between genetic polymorphisms of phospholipase A2 enzymes and Alzheimer's disease

Several genes have been related to late-onset Alzheimer's disease (LOAD). Phospholipases A2 (PLA2) influence the processing and secretion of the amyloid precursor protein, which gives rise to the beta-amyloid peptide, the major component of the amyloid plaque in AD. Hence, in the present study, polymorphisms of three genes encoding PLA2 enzymes group (cytosolic PLA2: BanI cPLA2 polymorphism; calcium-independent PLA2: AvrII iPLA2 polymorphism; PAFAH: Val279Phe PAFAH polymorphism) were analysed in a case-control sample using 58 patients with LOAD and 107 matched healthy controls. There was a genotypic association between the BanI cPLA2 polymorphism and LOAD (χ2=6.25, 2df, p=0.04), however there was no allelic association. There were no associations between AvrII iPLA2 and Val279Phe PAFAH polymorphisms and LOAD. These data suggest that the BanI cPLA2 polymorphism may play a role in the susceptibility for LOAD in our Brazilian sample.

Effects of nutritional supplements on aggression, rule-breaking, and psychopathology among young adult prisoners

In an earlier study, improvement of dietary status with food supplements led to a reduction in antisocial behavior among prisoners. Based on these earlier findings, a study of the effects of food supplements on aggression, rule-breaking, and psychopathology was conducted among young Dutch prisoners. Two hundred and twenty-one young adult prisoners (mean age=21.0, range 18-25 years) received nutritional supplements containing vitamins, minerals, and essential fatty acids or placebos, over a period of 1-3 months. As in the earlier (British) study, reported incidents were significantly reduced (P=.017, one-tailed) in the active condition (n=115), as compared with placebo (n=106). Other assessments, however, revealed no significant reductions in aggressiveness or psychiatric symptoms. As the incidents reported concerned aggressive and rule-breaking behavior as observed by the prison staff, the results are considered to be promising. However, as no significant improvements were found in a number of other (self-reported) outcome measures, the results should be interpreted with caution.

Oiling the brain: a review of randomized controlled trials of omega-3 fatty acids in psychopathology across the lifespan

Around one in four people suffer from mental illness at some stage in their lifetime. There is increasing awareness of the importance of nutrition, particularly omega-3 polyunsaturated fatty acids (n-3 PUFA), for optimal brain development and function. Hence in recent decades, researchers have explored effects of n-3 PUFA on mental health problems over the lifespan, from developmental disorders in childhood, to depression, aggression, and schizophrenia in adulthood, and cognitive decline, dementia and Alzheimer's disease in late adulthood. This review provides an updated overview of the published and the registered clinical trials that investigate effects of n-3 PUFA supplementation on mental health and behavior, highlighting methodological differences and issues.

Deficit in prepulse inhibition in mice caused by dietary n-3 fatty acid deficiency

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may be biosynthesized from a precursor alpha-linolenic acid (LNA) or obtained preformed in the diet. Dams were fed four diets with different levels of the various n-3 fatty acids during pregnancy and lactation, and their offspring were weaned to the same diets: "n-3 Deficient," containing (as % total fatty acids) 0.07% of LNA; "Low LNA" (0.4%); "High LNA" (4.8%); and a "DHA + EPA" diet, containing 0.4% of LNA, 2% DHA, and 2% EPA. Sensorimotor gating was measured by prepulse inhibition (PPI) of the acoustic startle response in C57Bl6 mice. The n-3 Deficient and Low LNA diets caused a substantial deficit in PPI compared to the DHA + EPA diet, whereas the High LNA diet induced a less pronounced, but significant reduction of PPI. These are the first data that demonstrate a deficit in sensorimotor gating in rodents caused by an inadequate amount of the n-3 fatty acids in the diet. Our results differentiate the effects of a High LNA diet from one with added EPA and DHA even though the difference in brain DHA content is only 12% between these dietary groups.

Decreased glutathione levels and antioxidant enzyme activities in untreated and treated schizophrenic patients

There is substantial evidence found in the literature that supports the fact that the presence of oxidative stress may play an important role in the physiopathology of schizophrenia. Previous studies have reported the occurrence of impairments in the glutathione levels and the activities of the antioxidant enzymes in patients suffering from schizophrenia. However, most of these studies were performed on treated patients. The present study evaluated treated schizophrenic patients (n=52) along with neuroleptic-free or untreated schizophrenic patients (n=36) and healthy controls (n=46). The blood glutathione levels: total glutathione (GSHt), reduced glutathione (GSHr), and oxidized glutathione (GSSG) as well as the activities of the antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were measured. The psychopathology of the patients was assessed through the Clinical Global Impressions-severity (CGI-severity). The tests revealed that in comparison with the healthy controls, the schizophrenic patients showed significantly lower levels of GSHr, SOD, and CAT. Among the schizophrenic patients, the activities of the antioxidant enzymes SOD and CAT were recorded to be significantly lower in untreated patients than in the treated ones. In addition, the levels of both GSHt and GSHr were found to be inversely correlated with the obtained CGI-severity score. These results evidently suggest that a decrease in the glutathione levels and the activities of the antioxidant enzymes in patients diagnosed with schizophrenia is not related to neuroleptic treatment and could be considered as a biological indicator of the degree of severity of the symptoms of schizophrenia.

Project DyAdd: Fatty acids and cognition in adults with dyslexia, ADHD, or both

Both attention deficit hyperactivity disorder (ADHD) and dyslexia are suggested to co-occur with altered fatty acid (FA) metabolism, but it is unknown how FAs are associated with the cognitive domains that characterize these disorders. In the project DyAdd, we investigated the associations between FAs in serum phospholipids and phonological processing, reading, spelling, arithmetic, executive functions, and attention. Healthy controls (n=36), adults with ADHD (n=26), dyslexia (n=36), or both (n=9) were included in the study. FAs included saturated, monounsaturated, total polyunsaturated, n-3, and n-6 FAs, together with n-6/n-3, AA/EPA, and LA/ALA ratios. When all the study subjects were included in the analyses, especially polyunsaturated FAs (PUFAs) were positively associated with cognition, but reading was least associated with FAs. These associations were modulated by gender, intelligence, n-3 PUFA intake, and group. Accordingly, within the ADHD group, only few associations emerged with PUFAs, n-6 PUFAs, and cognitive domains, whereas in the dyslexia group the more prevalent associations appeared with PUFAs and n-3 PUFAs.

Project DyAdd: Fatty acids in adult dyslexia, ADHD, and their comorbid combination

In project DyAdd, we compared the fatty acid (FA) profiles of serum phospholipids in adults with attention deficit hyperactivity disorder (ADHD) (n=26), dyslexia (n=36), their comorbid combination (n=9), and healthy controls (n=36). FA proportions were analyzed in a 2x2 design with Bonferroni corrected post hoc comparisons. A questionnaire was used to assess dietary fat quality and use of supplements. Results showed that ADHD and dyslexia were not associated with total saturated FAs, monounsaturated FAs, or n-3 polyunsaturated FAs (PUFAs). However, those with ADHD had elevated proportions of total n-6 PUFAs (including gamma-linolenic and adrenic acids) as compared to those without ADHD. Dyslexia was related to a higher proportion of monounsaturated nervonic acid and a higher ratio of n-6/n-3 PUFAs. Among females none of the associations were significant. However in males, all the original associations observed in all subjects remained and ADHD was associated with elevated nervonic acid and n-6/n-3 PUFA ratio like dyslexia. Controlling for poorly diagnosed reading difficulties, education, dietary fat quality, or use of FA supplements did not generally remove the originally observed associations.

Aberrant amino acid transport in fibroblasts from patients with bipolar disorder

Aberrant tyrosine transport is a repeated finding in fibroblasts from schizophrenic patients. The transport aberration could lead to disturbances in the dopaminergic and noradrenergic neurotransmitter systems. Tyrosine and tryptophan are the precursors of the neurotransmitters dopamine and serotonin. Disturbed dopaminergic, noradrenergic and serotoninergic systems are implicated as causes of bipolar disorder. Hence, the aim of this study was to explore whether patients with bipolar disorder have an aberrant transport of tyrosine and/or tryptophan. Fibroblast cell lines from patients with bipolar type-1 disorder (n=10) and healthy controls (n=10) were included in this study. All patients fulfilled the DSM-IV diagnostic criteria. The transport of amino acids across the cell membranes was measured by the cluster tray method. The kinetic parameters, maximal transport velocity (V(max)) and affinity constant (K(m)) were determined. A significantly lower V(max) for tyrosine (p=0.027) was found in patients with bipolar type-1 disorder in comparison to healthy controls. No significant differences in K(m) for tyrosine and in the kinetic parameters of tryptophan between patients with bipolar type-1 disorder and healthy controls were observed. The decreased tyrosine transport (low V(max)) found in this study may indicate less access of dopamine in the brain, resulting in disturbed dopaminergic and/or noradrenergic neurotransmission, that secondarily could lead to disturbances in other central neurotransmitter systems, such as the serotoninergic system. However, as sample size was small in this study and an age difference between patients and controls existed, the present findings should be considered as pilot data. Further studies with larger sample number are needed to elucidate the transport aberration and the significance of these findings.

Alternative treatments in pediatric bipolar disorder

There has been growing interest in the use of complementary and alternative treatments in pediatric bipolar disorder (BPD). There are limited data, however, regarding the safety and efficacy of these treatments. This article discusses select complementary and alternative treatments that have been considered for use in pediatric BPD and/or depression, including omega-3-fatty acids, inositol, St. John's wort, SAMe, melatonin, lecithin, and acupuncture. Background information, reference to available adult and pediatric data, proposed mechanisms of action, dosing, side effects, and precautions of these treatments are included. Across the board, more research is necessary and warranted regarding the long-term safety and efficacy of available complementary and alternative treatments for the management of pediatric BPD.

Is there a role for n-3 long-chain polyunsaturated fatty acids in the regulation of mood and behaviour? A review of the evidence to date from epidemiological studies, clinical studies and intervention trials

Selected biochemical evidence suggests a potential role for n-3 long-chain PUFA (n-3PUFA) in the regulation of mood and behaviour. The present paper reviews the relevant evidence, to date, from epidemiological studies, clinical studies and intervention trials. Most evidence is available investigating a role for n-3PUFA in depression, depressive illness and suicidal behaviour, but work is also available on anxiety and anxiety-related disorders, fatigue and fatigue-related disorders, aggression, hostility and anti-social behaviour, inattention, impulsivity and attention deficit hyperactivity disorder and schizophrenic disorders. For all these aspects of mood and behaviour, the evidence available is currently limited and highly inconsistent, both in terms of study methodology and study findings. There is a clear need for further work in this area.

Common effect of antipsychotics on the biosynthesis and regulation of fatty acids and cholesterol supports a key role of lipid homeostasis in schizophrenia

For decades, the dopamine hypothesis has gained the most attention in an attempt to explain the origin and the symptoms of schizophrenia. While this hypothesis offers an explanation for the relationship between psychotic symptoms and dopamine kinetics, it does not provide a direct explanation of the etiology of schizophrenia which remains poorly understood. Consequently, current antipsychotics that target neurotransmitter receptors, have limited and inconsistent efficacy. To gain insights into the mechanism of action of these drugs, we studied the expression profile of 12,490 human genes in a cell line treated with 18 antipsychotics, and compared it to that of a library of 448 other compounds used in a variety of disorders. Analysis reveals a common effect of antipsychotics on the biosynthesis and regulation of fatty acids and cholesterol, which is discussed in the context of a lipid hypothesis where alterations in lipid homeostasis might underlie the pathogenesis of schizophrenia. This finding may help research aimed at the development of novel treatments for this devastating disease.

Systemic hypotheses for generalized cognitive deficits in schizophrenia: a new take on an old problem

The schizophrenia research community, including government, industry, and academia, has made development of procognitive treatment strategies a priority. Much current research is directed at dividing broad impairments in cognition into more delineated components that might correspond to relatively specific neural systems and serve as targets for intervention. Sometimes overlooked in this ambitious agenda is the substantial neuropsychological literature that signals a more broadly generalized dysfunction in higher order cognitive functions in this illness. In this article, we argue that a generalized cognitive deficit is at the core of the disorder, is not a methodological artifact, and deserves more focused consideration from cognitive specialists in the field. Further, we weigh evidence that this broad deficit may have systemic biological underpinnings. At the level of the central nervous system, examples of findings that might help to account for broad cognitive impairment include gray and white matter irregularities, poor signal integration by neurons and neural networks, and abnormalities in glutamate and gamma-aminobutyric acid neurotransmission. Other, more speculative hypotheses focus on even broader somatic systems, including energy metabolism and inflammatory processes. Treatment implications of systemic conceptualizations of schizophrenia are also considered.

Improvement of aggressive behavior and quality of life impairment following S-adenosyl-methionine (SAM-e) augmentation in schizophrenia

S-adenosyl-methionine (SAM-e), functions as a primary methyl group donor for several metabolic compounds. Since SAM-e is involved in several metabolic processes, its administration may have a role in the amelioration of several disorders. In addition, SAM-e increases catechol-O-methyltransferase (COMT) enzyme activity, which may ameliorate aggressive symptoms in certain patients. We have therefore investigated the efficacy of SAM-e in managing schizophrenia symptomatology in patients with the low activity COMT polymorphism. Eighteen patients with chronic schizophrenia were randomly assigned to receive either SAM-e (800 mg) or placebo for 8 weeks in double-blind fashion. Results indicated some reduction in aggressive behavior and improved quality of life following SAM-e administration. Female patients showed improvement of depressive symptoms. Clinical improvement did not correlate with serum SAM-e levels. Two patients receiving SAM-e exhibited some exacerbation of irritability. This preliminary pilot short-term study cautiously supports SAM-e as an adjunct in management of aggressive behavior and quality of life impairment in schizophrenia.

Metabolomics: a global biochemical approach to the study of central nervous system diseases

Metabolomics, the omics science of biochemistry, is a global approach to understanding regulation of metabolic pathways and metabolic networks of a biological system. Metabolomics complements data derived from genomics, transcriptomics, and proteomics to assist in providing a systems approach to the study of human health and disease. In this review we focus on applications of metabolomics for the study of diseases of the nervous system. We share concepts in metabolomics, tools used in metabolic profiling and early findings from the study of neuropsychiatric diseases, and drugs used to treat these diseases. Metabolomics emerges as another powerful tool in central nervous system research.

Brain cell membrane motion-restricted phospholipids: a cerebral 31-phosphorus magnetic resonance spectroscopy study of patients with schizophrenia

This study directly assessed, for the first time, whether there was a change in brain cell motion-restricted membrane phospholipids in vivo in patients with schizophrenia with mild to moderate negative symptoms, by quantification of the underlying broad resonance signal of cerebral 31-phosphorus magnetic resonance scans. Cerebral 31-phosphorus magnetic resonance spectroscopy was carried out in 16 schizophrenia patients and 16 age- and gender-matched normal controls. Spectra were obtained from 70x70x70 mm3 voxels using an image-selected in vivo spectroscopy pulse sequence. There was no significant difference in the broad resonances between the two groups, with the mean (S.E.) percentage signal being 59.4 (5.6) for the patients and 53.5 (5.9) for the controls. The phosphomonoesters and phosphodiesters narrow signals also did not differ significantly, their ratio being 0.26 (0.01) in the patients and 0.25 (0.01) in the controls. These results appear to be at variance with the changes expected under the membrane phospholipid hypothesis of schizophrenia.

Lipidomics: a new window to biomedical frontiers

Lipids are a highly diverse class of molecules with crucial roles in cellular energy storage, structure and signaling. Lipid homeostasis is fundamental to maintain health, and lipid defects are central to the pathogenesis of important and devastating diseases. Newly emerging advances have facilitated the development of so-called lipidomics technologies and offer an opportunity to elucidate the mechanisms leading to disease. Furthermore, these advances also provide the tools to unravel the complexity of the 'allostatic forces' that allow maintenance of normal cellular/tissue phenotypes through the application of bioenergetically inefficient adaptive mechanisms. An alternative strategy is to focus on tissues with limited allostatic capacity, such as the eye, that could be used as readouts of metabolic stress over time. Identification of these allostatic mechanisms and pathological 'scares' might provide a window to unknown pathogenic mechanisms, as well as facilitate identification of early biomarkers of disease.

High throughput lipidomic profiling of schizophrenia and bipolar disorder brain tissue reveals alterations of free fatty acids, phosphatidylcholines, and ceramides

A mass spectrometry based high throughput approach was employed to profile white and gray matter lipid levels in the prefrontal cortex (Brodmann area 9) of 45 subjects including 15 schizophrenia and 15 bipolar disorder patients as well as 15 controls samples. We found statistically significant alterations in levels of free fatty acids and phosphatidylcholine in gray and white matter of both schizophrenia and bipolar disorder samples compared to controls. Also, ceramides were identified to be significantly increased in white matter of both neuropsychiatric disorders as compared to control levels. The patient cohort investigated in this study includes a number of drug naive as well as untreated patients, allowing the assessment of drug effects on lipid levels. Our findings indicate that while gray matter phosphatidylcholine levels were influenced by antipsychotic medication, this was not the case for phosphatidylcholine levels in white matter. Changes in free fatty acids or ceramides in either white or gray matter also did not appear to be influenced by antipsychotic treatment. To assess lipid profiles in the living patient, we also profiled lipids of 40 red blood cell samples, including 7 samples from drug naive first onset patients. We found significant alterations in the concentrations of free fatty acids as well as ceramide. Overall, our findings suggest that lipid abnormalities may be a disease intrinsic feature of both schizophrenia and bipolar disorder reflected by significant changes in the central nervous system as well as peripheral tissues.