Effects of chronic clozapine administration on markers of arachidonic acid cascade and synaptic integrity in rat brain

Arachidonic acid in aging: New roles for old players

BACKGROUND

Arachidonic acid (AA), one of the most ubiquitous polyunsaturated fatty acids (PUFAs), provides fluidity to mammalian cell membranes. It is derived from linoleic acid (LA) and can be transformed into various bioactive metabolites, including prostaglandins (PGs), thromboxanes (TXs), lipoxins (LXs), hydroxy-eicosatetraenoic acids (HETEs), leukotrienes (LTs), and epoxyeicosatrienoic acids (EETs), by different pathways. All these processes are involved in AA metabolism. Currently, in the context of an increasingly visible aging world population, several scholars have revealed the essential role of AA metabolism in osteoporosis, chronic obstructive pulmonary disease, and many other aging diseases.

AIM OF REVIEW

Although there are some reviews describing the role of AA in some specific diseases, there seems to be no or little information on the role of AA metabolism in aging tissues or organs. This review scrutinizes and highlights the role of AA metabolism in aging and provides a new idea for strategies for treating aging-related diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

As a member of lipid metabolism, AA metabolism regulates the important lipids that interfere with the aging in several ways. We present a comprehensivereviewofthe role ofAA metabolism in aging, with the aim of relieving the extreme suffering of families and the heavy economic burden on society caused by age-related diseases. We also collected and summarized data on anti-aging therapies associated with AA metabolism, with the expectation of identifying a novel and efficient way to protect against aging.

Existing and Novel Biological Therapeutics in Suicide Prevention

We summarize outcomes for several pharmacologic and neurostimulatory approaches that have been considered potential treatments to reduce suicide risk, namely, by reducing suicide deaths, attempts, and ideation in various clinical populations. Available treatments include clozapine, lithium, antidepressants, antipsychotics, electroconvulsive therapy, and transcranial magnetic stimulation. The novel repurposing of ketamine as a potential suicide risk-mitigating agent in the acute setting is also discussed. Research pathways to better understand and treat suicidal ideation and behavior from a neurobiological perspective are proposed in light of this foundation of information and the limitations and challenges inherent in suicide research. Such pathways include trials of fast-acting medications, registry approaches to identify appropriate patients for trials, identification of biomarkers, neuropsychological vulnerabilities, and endophenotypes through the study of known suicide risk-mitigating agents in hope of determining mechanisms of pathophysiology and the action of protective biological interventions. Reprinted from Am J Prev Med 2014; 47:S195-S203, with permission from Elsevier. Copyright © 2014.

Canonical and Non-Canonical Antipsychotics' Dopamine-Related Mechanisms of Present and Next Generation Molecules: A Systematic Review on Translational Highlights for Treatment Response and Treatment-Resistant Schizophrenia

Schizophrenia is a severe psychiatric illness affecting almost 25 million people worldwide and is conceptualized as a disorder of synaptic plasticity and brain connectivity. Antipsychotics are the primary pharmacological treatment after more than sixty years after their introduction in therapy. Two findings hold true for all presently available antipsychotics. First, all antipsychotics occupy the dopamine D2 receptor (D2R) as an antagonist or partial agonist, even if with different affinity; second, D2R occupancy is the necessary and probably the sufficient mechanism for antipsychotic effect despite the complexity of antipsychotics' receptor profile. D2R occupancy is followed by coincident or divergent intracellular mechanisms, implying the contribution of cAMP regulation, β-arrestin recruitment, and phospholipase A activation, to quote some of the mechanisms considered canonical. However, in recent years, novel mechanisms related to dopamine function beyond or together with D2R occupancy have emerged. Among these potentially non-canonical mechanisms, the role of Na²⁺ channels at the dopamine at the presynaptic site, dopamine transporter (DAT) involvement as the main regulator of dopamine concentration at synaptic clefts, and the putative role of antipsychotics as chaperones for intracellular D2R sequestration, should be included. These mechanisms expand the fundamental role of dopamine in schizophrenia therapy and may have relevance to considering putatively new strategies for treatment-resistant schizophrenia (TRS), an extremely severe condition epidemiologically relevant and affecting almost 30% of schizophrenia patients. Here, we performed a critical evaluation of the role of antipsychotics in synaptic plasticity, focusing on their canonical and non-canonical mechanisms of action relevant to the treatment of schizophrenia and their subsequent implication for the pathophysiology and potential therapy of TRS.

Antipsychotics-Induced Changes in Synaptic Architecture and Functional Connectivity: Translational Implications for Treatment Response and Resistance

Schizophrenia is a severe mental illness characterized by alterations in processes that regulate both synaptic plasticity and functional connectivity between brain regions. Antipsychotics are the cornerstone of schizophrenia pharmacological treatment and, beyond occupying dopamine D2 receptors, can affect multiple molecular targets, pre- and postsynaptic sites, as well as intracellular effectors. Multiple lines of evidence point to the involvement of antipsychotics in sculpting synaptic architecture and remodeling the neuronal functional unit. Furthermore, there is an increasing awareness that antipsychotics with different receptor profiles could yield different interregional patterns of co-activation. In the present systematic review, we explored the fundamental changes that occur under antipsychotics' administration, the molecular underpinning, and the consequences in both acute and chronic paradigms. In addition, we investigated the relationship between synaptic plasticity and functional connectivity and systematized evidence on different topographical patterns of activation induced by typical and atypical antipsychotics.

Serotonin Receptor 5-HT2A Regulates TrkB Receptor Function in Heteroreceptor Complexes

Serotonin receptor 5-HT_2A and tropomyosin receptor kinase B (TrkB) strongly contribute to neuroplasticity regulation and are implicated in numerous neuronal disorders. Here, we demonstrate a physical interaction between 5-HT_2A and TrkB in vitro and in vivo using co-immunoprecipitation and biophysical and biochemical approaches. Heterodimerization decreased TrkB autophosphorylation, preventing its activation with agonist 7,8-DHF, even with low 5-HT_2A receptor expression. A blockade of 5-HT_2A receptor with the preferential antagonist ketanserin prevented the receptor-mediated downregulation of TrkB phosphorylation without restoring the TrkB response to its agonist 7,8-DHF in vitro. In adult mice, intraperitoneal ketanserin injection increased basal TrkB phosphorylation in the frontal cortex and hippocampus, which is in accordance with our findings demonstrating the prevalence of 5-HT_2A–TrkB heteroreceptor complexes in these brain regions. An expression analysis revealed strong developmental regulation of 5-HT_2A and TrkB expressions in the cortex, hippocampus, and especially the striatum, demonstrating that the balance between TrkB and 5-HT_2A may shift in certain brain regions during postnatal development. Our data reveal the functional role of 5-HT_2A–TrkB receptor heterodimerization and suggest that the regulated expression of 5-HT_2A and TrkB is a molecular mechanism for the brain-region-specific modulation of TrkB functions during development and under pathophysiological conditions.

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

COX-2 pathway is upregulated in ultra-high risk individuals for psychosis

BACKGROUND

The identification of Ultra-High Risk (UHR) individuals is thought to be useful for early intervention to improve psychosis outcomes. However, transition rates vary widely, and there is an effort to make these criteria more specific and accurate. Neuroinflammation has been discussed in the pathophysiology of psychosis. The metabolism of eicosanoids is a key process in inflammatory states. Therefore, we investigated whether the study of the inflammatory COX-2 pathway through the quantification of the eicosanoid levels can be a useful approach for the characterisation of UHR individuals.

METHODS

One hundred and twenty-two individuals were included in this study (67 UHR and 55 controls) based on performance on the Prodromal Questionnaire. UHR status was assessed by Structured Interview for Prodromal Syndromes (SIPS). We determined the levels of Prostaglandin F_2α (PGF_2α), Prostaglandin E₂ (PGE₂), and Thromboxane B₂ (TxB₂) in plasma using ELISA assays.

RESULTS

Concentrations of PGE₂ and TxB₂ were increased in UHR compared to controls (p = 0.01 and p < 0.05, respectively). PGE₂ and PGF_2α levels were correlated to negative symptoms (p < 0.01 and p < 0.05), whereas TxB₂ correlated with positive symptoms (p = 0.05) as assessed by the SIPS.

CONCLUSIONS

Our findings suggest that overactivation of the COX-2 pathway may be related to an increased risk for psychosis. However, our data do not allow us to draw conclusions related to the cause-effect mechanisms. Future studies should determine whether the levels of the eicosanoids have a predictive value for the transition of UHR to frank psychosis.

Moderate blood alcohol and brain neurovulnerability: Selective depletion of calcium-independent phospholipase A2, omega-3 docosahexaenoic acid, and its synaptamide derivative as a potential harbinger of deficits in anti-inflammatory reserve

BACKGROUND

Repetitive, highly elevated blood alcohol (ethanol) concentrations (BACs) of 350 to 450 mg/dl over several days cause brain neurodegeneration and coincident neuroinflammation in adult rats localized in the hippocampus (HC), temporal cortex (especially the entorhinal cortex; ECX), and olfactory bulb (OB). The profuse neuroinflammation involves microgliosis, increased proinflammatory cytokines, and elevations of Ca+2 -dependent phospholipase A2 (cPLA2) and secretory PLA2 (sPLA2), which both mobilize proinflammatory ω-6 arachidonic acid (ARA). In contrast, Ca+2 -independent PLA2 (iPLA2) and anti-inflammatory ω-3 docosahexaenoic acid (DHA), a polyunsaturated fatty acid regulated primarily by iPLA2, are diminished. Furthermore, supplemented DHA exerts neuroprotection. Given uncertainties about the possible effects of lower circulating BACs that are common occurring during short- term binges, we examined how moderate BACs affected the above inflammatory events, and the impact of supplemented DHA.

METHODS AND RESULTS

Young adult male rats sustaining upper-moderate BACs (~150 mg/dl) from once-daily alcohol intubations were sacrificed with appropriate controls after 1 week. The HC, ECX and OB were quantitatively examined using immunoblotting, neurodegeneration staining, and lipidomics assays. Whereas neurodegeneration, increases in cPLA2 IVA, sPLA2 IIA, and ARA, and microglial activation were not detected, the HC and ECX regions demonstrated significantly reduced iPLA2 levels. Levels of DHA and synaptamide, its anti-inflammatory N-docosahexaenoylethanolamide derivative, also were lower in HC, and DHA supplementation prevented the iPLA2 decrements in HC. Additionally, adult mice maintaining upper-moderate BACs from limited alcohol binges had reduced midbrain iPLA2 levels.

CONCLUSIONS

The apparently selective depletion by moderate BACs of the metabolically linked anti-inflammatory triad of hippocampal iPLA2, DHA, and synaptamide, and of iPLA2 in the ECX, potentially indicates an unappreciated deficit in brain anti-inflammatory reserve that may be a harbinger of regional neurovulnerability.

Plasma Lysophosphatidylcholine and Lysophosphatidylethanolamine Levels Were Associated With the Therapeutic Response to Olanzapine in Female Antipsychotics-naïve First-episode Patients With Schizophrenia

Background: Accumulating studies have shown that the pathophysiology of schizophrenia may be associated with aberrant lysophospolipid metabolism in the early stage of brain development. Recent evidence demonstrates that antipsychotic medication can regulate the phospholipase activity. However, it remains unclear whether lysophospolipid is associated with the therapeutic response to antipsychotic medication in schizophrenia. This study aimed to investigate the influence of olanzapine monotherapy on lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE) and the association between symptom improvement and changes of LPC and LPE levels during treatment in antipsychotic-naïve first-episode (ANFE) patients.

Materials and Methods: The psychotic symptoms were evaluated by the Positive and Negative Syndrome Scale (PANSS). 25 ANFE patients were treated with olanzapine for 1 mo. The levels of LPC and LPE were determined and psychotic symptoms were assessed at baseline and at 1-mo follow-up.

Results: Relative to baseline, the psychotic symptoms were significantly reduced after olanzapine treatment, except for negative symptoms. Moreover, the levels of most LPC and LPE increased after treatment. Interestingly, increased LPC(18:3) and LPC(20:2) levels were positively associated with the reduction rates of PANSS positive subscore. In addition, baseline levels of LPE(20:5), LPE(18:3) and LPE(22:5) were predictors for the reduction of positive symptoms.

Conclusion: Our study reveals that the levels of lysophospolipid are associated with the improvement of positive symptoms, indicating that LPC may be a potential therapeutic target for olanzapine in schizophrenia. Moreover, baseline LPE levels were predictive biomarkers for the therapeutic response to olanzapine in the early stage of treatment in ANFE patients.

The Emerging Role of the Innate Immune Response in Idiosyncratic Drug Reactions

Idiosyncratic drug reactions (IDRs) range from relatively common, mild reactions to rarer, potentially life-threatening adverse effects that pose significant risks to both human health and successful drug discovery. Most frequently, IDRs target the liver, skin, and blood or bone marrow. Clinical data indicate that most IDRs are mediated by an adaptive immune response against drug-modified proteins, formed when chemically reactive species of a drug bind to self-proteins, making them appear foreign to the immune system. Although much emphasis has been placed on characterizing the clinical presentation of IDRs and noting implicated drugs, limited research has focused on the mechanisms preceding the manifestations of these severe responses. Therefore, we propose that to address the knowledge gap between drug administration and onset of a severe IDR, more research is required to understand IDR-initiating mechanisms; namely, the role of the innate immune response. In this review, we outline the immune processes involved from neoantigen formation to the result of the formation of the immunologic synapse and suggest that this framework be applied to IDR research. Using four drugs associated with severe IDRs as examples (amoxicillin, amodiaquine, clozapine, and nevirapine), we also summarize clinical and animal model data that are supportive of an early innate immune response. Finally, we discuss how understanding the early steps in innate immune activation in the development of an adaptive IDR will be fundamental in risk assessment during drug development. SIGNIFICANCE STATEMENT: Although there is some understanding that certain adaptive immune mechanisms are involved in the development of idiosyncratic drug reactions, the early phase of these immune responses remains largely uncharacterized. The presented framework refocuses the investigation of IDR pathogenesis from severe clinical manifestations to the initiating innate immune mechanisms that, in contrast, may be quite mild or clinically silent. A comprehensive understanding of these early influences on IDR onset is crucial for accurate risk prediction, IDR prevention, and therapeutic intervention.

Putative neuroprotective pharmacotherapies to target the staged progression of mental illness

AIM

Neuropsychiatric disorders including depression, bipolar and schizophrenia frequently exhibit a neuroprogressive course from prodrome to chronicity. There are a range of agents exhibiting capacity to attenuate biological mechanisms associated with neuroprogression. This review will update the evidence for putative neuroprotective agents including clinical efficacy, mechanisms of action and limitations in current assessment tools, and identify novel agents with neuroprotective potential.

METHOD

Data for this review were sourced from online databases PUBMED, Embase and Web of Science. Only data published since 2012 were included in this review, no data were excluded based on language or publication origin.

RESULTS

Each of the agents reviewed inhibit one or multiple pathways of neuroprogression including: inflammatory gene expression and cytokine release, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophin dysregulation and apoptotic signalling. Some demonstrate clinical efficacy in preventing neural damage or loss, relapse or cognitive/functional decline. Agents include: the psychotropic medications lithium, second generation antipsychotics and antidepressants; other pharmacological agents such as minocycline, aspirin, cyclooxygenase-2 inhibitors, statins, ketamine and alpha-2-delta ligands; and others such as erythropoietin, oestrogen, leptin, N-acetylcysteine, curcumin, melatonin and ebselen.

CONCLUSIONS

Signals of evidence of clinical neuroprotection are evident for a number of candidate agents. Adjunctive use of multiple agents may present a viable avenue to clinical realization of neuroprotection. Definitive prospective studies of neuroprotection with multimodal assessment tools are required.

Clozapine impact on FosB/ΔFosB expression in stress preconditioned rats: response to a novel stressor

OBJECTIVE

Prolonged treatment with neuroleptics has been shown to induce FosB/ΔFosB expression in several brain regions including the medial prefrontal cortex, dorsomedial and dorsolateral striatum, ventrolateral and dorsolateral septum, nucleus accumbens shell and core, and the hypothalamic paraventricular nucleus (PVN). Some of these regions are known to be also stress responsive. This study was designed to determine whether repeated clozapine (CLZ) administration for 7 consecutive days to Wistar rats may modify FosB/ΔFosB expression in the above-mentioned brain areas induced by acute stress or novel stressor that followed 13-day chronic mild stress preconditioning.

METHODS

Following experimental groups were used: unstressed animals treated with vehicle/ CLZ for 7 days; 7-day vehicle/CLZ-treated animals on the last day exposed to acute stress - forced swimming (FSW); and animals preconditioned with stress for 13 days treated from the 8th day with vehicle/CLZ and on the 14th day exposed to novel stress - FSW.

RESULTS

In the unstressed animals CLZ markedly increased FosB/ΔFosB immunoreactivity in the ventrolateral septum and PVN. FSW elevated FosB/ΔFosB expression in the medial prefrontal cortex, striatum, and septum. CLZ markedly potentiated the effect of the FSW on FosB/ΔFosB expression in the PVN, but suppressed it in the dorsomedial striatum. Novel stress with stress preconditioning increased FosB/ΔFosB immunoreactivity in the prefrontal cortex, striatum, ventrolateral septum, and the PVN. In the nucleus accumbens the effect of the novel stressor was potentiated by CLZ.

CONCLUSION

Our data indicate that CLZ may modulate the acute as well as novel stress effects on FosB/ΔFosB expression but its effect differs within the individual brain regions.

Alterations of eicosanoids and related mediators in patients with schizophrenia

Schizophrenia (SCZ) is a multifactorial psychiatric disorder. Currently, its molecular pathogenesis remains largely unknown, and no reliable test for diagnosis and therapy monitoring is available. Polyunsaturated fatty acids (PUFAs) and their derived eicosanoid signaling abnormalities are relevant to the pathophysiology of schizophrenia. However, comprehensive analysis of eicosanoids and related mediators for schizophrenia is very rare. In this study, we applied a targeted liquid chromatography-mass spectrometry based method to monitor 158 PUFAs, eicosanoids and related mediators from enzyme-dependent or independent pathways, in the serum samples of 109 healthy controls, and 115 schizophrenia patients at baseline and after an 8-week period of antipsychotic therapy. Twenty-three metabolites were identified to be significantly altered in SCZ patients at baseline compared to healthy controls, especially arachidonic acid (AA) derived eicosanoids. These disturbances may be related to altered immunological reactions and neurotransmitter signaling. After 8-week antipsychotic treatment, there were 22 metabolites, especially AA and linoleic acid derived eicosanoids, significantly altered in posttreatment patients. Some metabolites, such as several AA derived prostaglandins, thromboxanes, and di-hydroxy-eicosatrienoic acids were reversed toward normal levels after treatment. Based on univariate analysis and orthogonal partial least-squares discriminant analysis, anandamide, oleoylethanolamine, and AA were selected as a panel of potential biomarkers for differentiating baseline SCZ patients from controls, which showed a high sensitivity (0.907), good specificity (0.843) and excellent area under the receiver operating characteristic curve (0.940). This study provided a new perspective to understand the pathophysiological mechanism and identify potential biomarkers of SCZ.

Ageing: Is there a role for arachidonic acid and other bioactive lipids? A review

Ageing is inevitable. Recent studies suggest that it could be delayed. Low-grade systemic inflammation is seen in type 2 diabetes mellitus, hypertension and endothelial dysfunction that are common with increasing age. In all these conditions, an alteration in arachidonic acid (AA) metabolism is seen in the form of increased formation of pro-inflammatory eicosanoids and decreased production of anti-inflammatory lipoxins, resolvins, protectins and maresins and decreased activity of desaturases. Calorie restriction, exercise and parabiosis delay age-related changes that could be related to enhanced proliferation of stem cells, decrease in inflammation and transfer of GDF-11 (growth differentiation factor-11) and other related molecules from the young to the old, increase in the formation of lipoxin A4, resolvins, protectins and maresins, hydrogen sulfide (H2S) and nitric oxide (NO); inhibition of ageing-related hypothalamic or brain IKK-β and NF-kB activation, decreased gonadotropin-releasing hormone (GnRH) release resulting in increased neurogenesis and consequent decelerated ageing. This suggests that hypothalamus participates in ageing process. N-acylethanolamines (NAEs) and lipid-derived signalling molecules can be tuned favorably under dietary restriction to extend lifespan and/or prevent advanced age associated diseases in an mTOR dependent pathway manner. Sulfur amino acid (SAA) restriction increased hydrogen sulfide (H2S) production and protected tissues from hypoxia and tissue damage. Anti-inflammatory metabolites formed from AA such as LXA4, resolvins, protectins and maresins enhance production of NO, CO, H2S; suppress NF-kB expression and alter mTOR expression and thus, may aid in delaying ageing process. Dietary restriction and exercise enhance AA metabolism to form LXA4, resolvins, protectins and maresins that have anti-inflammatory actions. AA and their metabolites also influence stem cell biology, enhance neurogenesis to improve memory and augment autophagy to prolong life span. Thus, AA and other PUFAs and their anti-inflammatory metabolites inhibit inflammation, augment stem cell proliferation, restore to normal lipid-derived signaling molecules and NO and H2S production, enhance autophagy and prolong life span.

Studies on Prostaglandin-Endoperoxide Synthase 1: Lower Levels in Schizophrenia and After Treatment with Antipsychotic Drugs in Conjunction with Aspirin

Background

Antipsychotic drugs plus aspirin (acetylsalicylic acid), which targets prostaglandin-endoperoxide synthase 1 (PTGS1: COX1), improved therapeutic outcomes when treating schizophrenia. Our microarray data showed higher levels of PTGS1 mRNA in the dorsolateral prefrontal cortex from subjects with schizophrenia of long duration of illness, suggesting aspirin plus antipsychotic drugs could have therapeutic effects by lowering PTGS1 expression in the cortex of subjects with the disorder.

Methods

We used Western blotting to measure levels of PTSG1 protein in human postmortem CNS, rat and mouse cortex, and cells in culture.

Results

Compared with controls, PTGS1 levels were 41% lower in the dorsolateral prefrontal cortex (P<.01), but not the anterior cingulate or frontal pole, from subjects with schizophrenia. Levels of PTGS1 were not changed in the dorsolateral prefrontal cortex in mood disorders or in the cortex of rats treated with antipsychotic drugs. There was a strong trend (P=.05) to lower cortical PTGS1 10 months after mice were treated postnatally with polyinosinic-polycytidylic acid sodium salt (Poly I:C), consistent with cortical PTGS1 being lower in adult mice after exposure to an immune activator postnatally. In CCF-STTG1 cells, a human-derived astrocytic cell line, aspirin caused a dose-dependent decrease in PTGS1 that was decreased further with the addition of risperidone.

Conclusions

Our data suggest low levels of dorsolateral prefrontal cortex PTGS1 could be associated with the pathophysiology of schizophrenia, and improved therapeutic outcome from treating schizophrenia with antipsychotic drugs augmented with aspirin may be because such treatment lowers cortical PTGS1.

Immediate-Early Genes Modulation by Antipsychotics: Translational Implications for a Putative Gateway to Drug-Induced Long-Term Brain Changes

An increasing amount of research aims at recognizing the molecular mechanisms involved in long-lasting brain architectural changes induced by antipsychotic treatments. Although both structural and functional modifications have been identified following acute antipsychotic administration in humans, currently there is scarce knowledge on the enduring consequences of these acute changes. New insights in immediate-early genes (IEGs) modulation following acute or chronic antipsychotic administration may help to fill the gap between primary molecular response and putative long-term changes. Moreover, a critical appraisal of the spatial and temporal patterns of IEGs expression may shed light on the functional "signature" of antipsychotics, such as the propensity to induce motor side effects, the potential neurobiological mechanisms underlying the differences between antipsychotics beyond D2 dopamine receptor affinity, as well as the relevant effects of brain region-specificity in their mechanisms of action. The interest for brain IEGs modulation after antipsychotic treatments has been revitalized by breakthrough findings such as the role of early genes in schizophrenia pathophysiology, the involvement of IEGs in epigenetic mechanisms relevant for cognition, and in neuronal mapping by means of IEGs expression profiling. Here we critically review the evidence on the differential modulation of IEGs by antipsychotics, highlighting the association between IEGs expression and neuroplasticity changes in brain regions impacted by antipsychotics, trying to elucidate the molecular mechanisms underpinning the effects of this class of drugs on psychotic, cognitive and behavioral symptoms.

Plasma linoleic acid partially mediates the association of bipolar disorder on self-reported mental health scales

We have shown that bipolar individuals have reduced quality diets, including lower intake of polyunsaturated fatty acids (PUFA). We have also reported reduced plasma levels of the n-6 PUFA, linoleic acid (LA), and the n-3 PUFA, eicosapentaenoic acid (EPA) in bipolar subjects. In the current analysis we hypothesized that LA and EPA plasma levels would mediate lower self-reported mental health and life functioning scores in bipolar subjects. In a cross-sectional study, we collected a 7-day diet record in bipolar (n = 56) and control subjects (n = 46) followed by a fasted blood draw. We used structured equation modeling path analysis to test for mediating effects of dietary intake and plasma levels of LA and EPA on self-reported mental health questionnaire scores, including the Life Functioning Questionnaire (LFQ), the Patient Health Questionnaire (PHQ9), and the Short Form Health Survey (SF12), extracting the mental health component summary score (SF12-MH). We adjusted for age, gender, psychiatric medication use, body mass index (BMI), and total caloric intake as covariates with bipolar disorder as the primary predictor. We found a significant path association from bipolar disorder to lower plasma LA levels (p = 0.03) and significant paths from plasma LA to PHQ9 (p = 0.05), LFQ (p = 0.01) and SF12-MH (p = 0.05) scores, such that lower plasma LA predicted worse outcomes. We found no significant paths from plasma EPA levels to any of the outcome measures. These findings suggest that plasma LA levels partially mediate the effect of bipolar disorder on self-reported measures of mental health and life functioning.

Synthetic and natural inhibitors of phospholipases A2: their importance for understanding and treatment of neurological disorders

Phospholipases A2 (PLA2) are a diverse group of enzymes that hydrolyze membrane phospholipids into arachidonic acid and lysophospholipids. Arachidonic acid is metabolized to eicosanoids (prostaglandins, leukotrienes, thromboxanes), and lysophospholipids are converted to platelet-activating factors. These lipid mediators play critical roles in the initiation, maintenance, and modulation of neuroinflammation and oxidative stress. Neurological disorders including excitotoxicity; traumatic nerve and brain injury; cerebral ischemia; Alzheimer's disease; Parkinson's disease; multiple sclerosis; experimental allergic encephalitis; pain; depression; bipolar disorder; schizophrenia; and autism are characterized by oxidative stress, inflammatory reactions, alterations in phospholipid metabolism, accumulation of lipid peroxides, and increased activities of brain phospholipase A2 isoforms. Several old and new synthetic inhibitors of PLA2, including fatty acid trifluoromethyl ketones; methyl arachidonyl fluorophosphonate; bromoenol lactone; indole-based inhibitors; pyrrolidine-based inhibitors; amide inhibitors, 2-oxoamides; 1,3-disubstituted propan-2-ones and polyfluoroalkyl ketones as well as phytochemical based PLA2 inhibitors including curcumin, Ginkgo biloba and Centella asiatica extracts have been discovered and used for the treatment of neurological disorders in cell culture and animal model systems. The purpose of this review is to summarize information on selective and potent synthetic inhibitors of PLA2 as well as several PLA2 inhibitors from plants, for treatment of oxidative stress and neuroinflammation associated with the pathogenesis of neurological disorders.

Peripheral BDNF: a candidate biomarker of healthy neural activity during learning is disrupted in schizophrenia

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptogenesis and synaptic plasticity underlying learning. However, a relationship between circulating BDNF levels and brain activity during learning has not been demonstrated in humans. Reduced brain BDNF levels are found in schizophrenia and functional neuroimaging studies of probabilistic association learning in schizophrenia have demonstrated reduced activity in a neural network that includes the prefrontal and parietal cortices and the caudate nucleus. We predicted that brain activity would correlate positively with peripheral BDNF levels during probabilistic association learning in healthy adults and that this relationship would be altered in schizophrenia.

METHOD

Twenty-five healthy adults and 17 people with schizophrenia or schizo-affective disorder performed a probabilistic association learning test during functional magnetic resonance imaging (fMRI). Plasma BDNF levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We found a positive correlation between circulating plasma BDNF levels and brain activity in the parietal cortex in healthy adults. There was no relationship between plasma BDNF levels and task-related activity in the prefrontal, parietal or caudate regions in schizophrenia. A direct comparison of these relationships between groups revealed a significant diagnostic difference.

CONCLUSIONS

This is the first study to show a relationship between peripheral BDNF levels and cortical activity during learning, suggesting that plasma BDNF levels may reflect learning-related brain activity in healthy humans. The lack of relationship between plasma BDNF and task-related brain activity in patients suggests that circulating blood BDNF may not be indicative of learning-dependent brain activity in schizophrenia.

Is schizophrenia a neurodegenerative disease? Evidence from age-related decline of brain-derived neurotrophic factor in the brains of schizophrenia patients and matched nonpsychiatric controls

BACKGROUND

Brain-derived neurotrophic factor (BDNF) protein levels decline in the brain during senescence and are also shown to be reduced in schizophrenia patients. BDNF is present in both the gray and white matters of the brain. It is unclear whether BDNF abnormalities in schizophrenia are specific to gray and/or white matter.

OBJECTIVE

We hypothesized that the age-related BDNF decline is abnormal and contributes to the reduced BDNF in schizophrenia.

METHODS

We tested this hypothesis by measuring BDNF protein levels in postmortem gray and white matter, using the prefrontal cortex (PFC) and the genu of the corpus callosum as regions of interests, from 20 schizophrenia patients and 20 matched nonpsychiatric controls. Samples were selected across the adult lifespan--from 20 to 80 years of age.

RESULTS

PFC gray matter BDNF protein levels were significantly lower in older age in both nonpsychiatric comparisons and patients, while BDNF in white matter did not decrease significantly with age in either group. PFC BDNF was linearly lower from 20 to 80 years of age in nonpsychiatric comparisons. In schizophrenia, the age effect was similarly linear in younger patients but a decline did not occur in older patients.

CONCLUSION

PFC BDNF does not follow a normative linear age effect in schizophrenia patients as they grow older, which may represent a 'floor effect' due to earlier decline or a survivor cohort of older patient donors who are less susceptible to a schizophrenia-related pathological aging process.

Existing and novel biological therapeutics in suicide prevention

We summarize outcomes for several pharmacologic and neurostimulatory approaches that have been considered potential treatments to reduce suicide risk, namely, by reducing suicide deaths, attempts, and ideation in various clinical populations. Available treatments include clozapine, lithium, antidepressants, antipsychotics, electroconvulsive therapy, and transcranial magnetic stimulation. The novel repurposing of ketamine as a potential suicide risk-mitigating agent in the acute setting is also discussed. Research pathways to better understand and treat suicidal ideation and behavior from a neurobiological perspective are proposed in light of this foundation of information and the limitations and challenges inherent in suicide research. Such pathways include trials of fast-acting medications, registry approaches to identify appropriate patients for trials, identification of biomarkers, neuropsychological vulnerabilities, and endophenotypes through the study of known suicide risk-mitigating agents in hope of determining mechanisms of pathophysiology and the action of protective biological interventions.

Inflamed moods: a review of the interactions between inflammation and mood disorders

Mood disorders have been recognized by the World Health Organization (WHO) as the leading cause of disability worldwide. Notwithstanding the established efficacy of conventional mood agents, many treated individuals continue to remain treatment refractory and/or exhibit clinically significant residual symptoms, cognitive dysfunction, and psychosocial impairment. Therefore, a priority research and clinical agenda is to identify pathophysiological mechanisms subserving mood disorders to improve therapeutic efficacy. During the past decade, inflammation has been revisited as an important etiologic factor of mood disorders. Therefore, the purpose of this synthetic review is threefold: 1) to review the evidence for an association between inflammation and mood disorders, 2) to discuss potential pathophysiologic mechanisms that may explain this association and 3) to present novel therapeutic options currently being investigated that target the inflammatory-mood pathway. Accumulating evidence implicates inflammation as a critical mediator in the pathophysiology of mood disorders. Indeed, elevated levels of pro-inflammatory cytokines have been repeatedly demonstrated in both major depressive disorder (MDD) and bipolar disorder (BD) patients. Further, the induction of a pro-inflammatory state in healthy or medically ill subjects induces 'sickness behavior' resembling depressive symptomatology. Potential mechanisms involved include, but are not limited to, direct effects of pro-inflammatory cytokines on monoamine levels, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, pathologic microglial cell activation, impaired neuroplasticity and structural and functional brain changes. Anti-inflammatory agents, such as acetyl-salicylic acid (ASA), celecoxib, anti-TNF-α agents, minocycline, curcumin and omega-3 fatty acids, are being investigated for use in mood disorders. Current evidence shows improved outcomes in mood disorder patients when anti-inflammatory agents are used as an adjunct to conventional therapy; however, further research is needed to establish the therapeutic benefit and appropriate dosage.

RETRACTED: Increased neuroinflammatory and arachidonic acid cascade markers, and reduced synaptic proteins, in the postmortem frontal cortex from schizophrenia patients

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editors. The National Institutes of Health has found that Dr. Jagadeesh S. Rao engaged in research misconduct by falsifying data. Data in Figures 1A, 1E, 3E and 3F were falsified. Dr. Rao was solely responsible for the falsification. None of the other authors are implicated in any way.

Does Systemic Inflammation Play a Role in Pediatric Psychosis?

CONTEXT

Human and animal studies have suggested an underlying inflammatory mechanism for a variety of neuropsychiatric disorders, including schizophrenia. To date, most available reports focused on adult patients.

OBJECTIVE

We wished to test the hypothesis that the first psychotic episode in youth is associated with inflammation.

PATIENTS

We studied patients admitted to a pediatric inpatient psychiatric unit. Patients (n=80) had new-onset psychosis diagnosed using DSM-IV TR criteria for Psychosis NOS, Schizophreniform Disorder or Schizoaffective Disorder. Patients were matched for age, race and gender with inpatient controls without psychosis within the same unit (n=66). We also compared these values to normal pediatric hematologic values. To study the role of inflammation in youth with psychosis, we collected serum samples of 28 children presenting with first-episode psychosis and compared their serum cytokine and S100B levels to eight healthy controls.

MAIN OUTCOME MEASURES

In this study, we measured serum markers of systemic inflammation.

RESULTS

Leukocyte counts revealed a statistically significant increase in absolute monocytes compared to patients without psychosis (0.61 ± 0.282 k/ml vs. 0.496 ± 0.14 k/ml; p<0.01) and lymphocytes (2.51 ± 0.84 k/ml vs. 2.24 ± 0.72 k/ml; p<0.05) in patients with psychosis. All other hematologic values were similar between the groups. In addition, psychosis was characterized by increased serum levels of S100B, a peripheral marker of blood-brain barrier (BBB) damage. Several inflammatory mediators (e.g., TNF-α, IL-1β, IL-6, IL-5, IL-10, and IFN-γ) were elevated in children with psychosis.

CONCLUSIONS

These results strongly support a link between systemic inflammation, blood-brain barrier disruption and first-episode psychosis in pediatric patients.

Elevated immune-inflammatory signaling in mood disorders: a new therapeutic target?

Converging translational evidence has implicated elevated immune-inflammatory signaling activity in the pathoetiology of mood disorders, including major depressive disorder and bipolar disorder. This is supported in part by cross-sectional evidence for increased levels of proinflammatory eicosanoids, cytokines and acute-phase proteins during mood episodes, and prospective longitudinal evidence for the emergence of mood symptoms in response to chronic immune-inflammatory activation. In addition, mood-stabilizer and atypical antipsychotic medications downregulate initial components of the immune-inflammatory signaling pathway, and adjunctive treatment with anti-inflammatory agents augment the therapeutic efficacy of antidepressant, mood stabilizer and atypical antipsychotic medications. Potential pathogenic mechanisms linked with elevated immune-inflammatory signaling include perturbations in central serotonin neurotransmission and progressive white matter pathology. Both heritable genetic factors and environmental factors including dietary fatty-acid composition may act in concert to sustain elevated immune-inflammatory signaling. Collectively, these data suggest that elevated immune-inflammatory signaling is a mechanism that is relevant to the pathoetiology of mood disorders, and may therefore represent a new therapeutic target for the development of more effective treatments.

Effect of repetitive daily ethanol intoxication on adult rat brain: significant changes in phospholipase A2 enzyme levels in association with increased PARP-1 indicate neuroinflammatory pathway activation

Collaborating on studies of subchronic daily intoxication in juvenile and adult rats, we examined whether the repetitive ethanol treatments at these two life stages altered levels of key neuroinflammation-associated proteins-aquaporin-4 (AQP4), certain phospholipase A2 (PLA2) enzymes, PARP-1 and caspase-3-in hippocampus (HC) and entorhinal cortex (EC). Significant changes in the proteins could implicate activation of specific neuroinflammatory signaling pathways in these rats as well as in severely binge-intoxicated adult animals that are reported to incur degeneration of vulnerable neurons in HC and EC. Male Wistar rats, ethanol-intoxicated (3 g/kg i.p.) once daily for 6 days over an 8-day interval beginning at 37 days old and repeated at age 68-75 days, were sacrificed 1 h after the day 75 dose (blood ethanol, 200- 230 mg/dl). Analysis of HC with an immunoblot technique showed that AQP4, Ca(+2)-dependent PLA2 (cPLA2 IVA), phosphorylated (activated) p-cPLA2, cleaved (89 kD) PARP (c-PARP), and caspase-3 levels were significantly elevated over controls, whereas Ca(+2)-independent PLA2 (iPLA2 VIA) was reduced ∼70%; however, cleaved caspase-3 was undetectable. In the EC, AQP4 was unchanged, but cPLA2 and p-cPLA2 were significantly increased while iPLA2 levels were diminished (∼40%) similar to HC, although just outside statistical significance (p = 0.06). In addition, EC levels of PARP-1 and c-PARP were significantly increased. The ethanol-induced activation of cPLA2 in association with reduced iPLA2 mirrors PLA2 changes in reports of neurotrauma and also of dietary omega-3 fatty acid depletion. Furthermore, the robust PARP-1 elevations accompanied by negligible caspase-3 activation indicate that repetitive ethanol intoxication may be potentiating non-apoptotic neurodegenerative processes such as parthanatos. Overall, the repetitive ethanol treatments appeared to instigate previously unappreciated neuroinflammatory pathways in vivo. The data provide insights into mechanisms of binge ethanol abuse that might suggest new therapeutic approaches to counter neurodegeneration and dementia.

Chronic clozapine reduces rat brain arachidonic acid metabolism by reducing plasma arachidonic acid availability

Chronic administration of mood stabilizers to rats down-regulates the brain arachidonic acid (AA) cascade. This down-regulation may explain their efficacy against bipolar disorder (BD), in which brain AA cascade markers are elevated. The atypical antipsychotics, olanzapine (OLZ) and clozapine (CLZ), also act against BD. When given to rats, both reduce brain cyclooxygenase activity and prostaglandin E(2) concentration; OLZ also reduces rat plasma unesterified and esterified AA concentrations, and AA incorporation and turnover in brain phospholipid. To test whether CLZ produces similar changes, we used our in vivo fatty acid method in rats given 10 mg/kg/day i.p. CLZ, or vehicle, for 30 days; or 1 day after CLZ washout. [1-(14) C]AA was infused intravenously for 5 min, arterial plasma was collected and high-energy microwaved brain was analyzed. CLZ increased incorporation coefficients ki * and decreased [corrected] rates J(in,i) of plasma unesterified AA into brain phospholipids. [corrected]. These effects disappeared after washout. Thus, CLZ and OLZ similarly down-regulated kinetics and cyclooxygenase expression of the brain AA cascade, likely by reducing plasma unesterified AA availability. Atypical antipsychotics and mood stabilizers may be therapeutic in BD by down-regulating, indirectly or directly respectively, the elevated brain AA cascade of that disease.