Nerve growth factor in never-medicated first-episode psychotic and medicated chronic schizophrenic patients: possible implications for treatment outcome

Association of Peripheral Inflammatory Biomarkers and Growth Factors Levels with Sex, Therapy and Other Clinical Factors in Schizophrenia and Patient Stratification Based on These Data

Multiple lines of evidence are known to confirm the pro-inflammatory state of some patients with schizophrenia and the involvement of inflammatory mechanisms in the pathogenesis of psychosis. The concentration of peripheral biomarkers is associated with the severity of inflammation and can be used for patient stratification. Here, we analyzed changes in serum concentrations of cytokines (IL-1β, IL-2, IL-4, IL-6, IL-10, IL-21, APRIL, BAFF, PBEF/Visfatin, IFN-α, and TNF-α) and growth/neurotrophic factors (GM-CSF, NRG1-β1, NGF-β, and GDNF) in patients with schizophrenia in an exacerbation phase. IL-1β, IL-2, IL-4, IL-6, BAFF, IFN-α, GM-CSF, NRG1-β1, and GDNF increased but TNF-α and NGF-β decreased in schizophrenia compared to healthy individuals. Subgroup analysis revealed the effect of sex, prevalent symptoms, and type of antipsychotic therapy on biomarker levels. Females, patients with predominantly negative symptoms, and those taking atypical antipsychotics had a more pro-inflammatory phenotype. Using cluster analysis, we classified participants into "high" and "low inflammation" subgroups. However, no differences were found in the clinical data of patients in these subgroups. Nevertheless, more patients (17% to 25.5%) than healthy donors (8.6% to 14.3%) had evidence of a pro-inflammatory condition depending on the clustering approach used. Such patients may benefit from personalized anti-inflammatory therapy.

Dysregulation of Synaptic Plasticity Markers in Schizophrenia

Schizophrenia is a mental disorder characterized by cognitive impairment resulting in compromised quality of life. Since the regulation of synaptic plasticity has functional implications in various aspects of cognition such as learning, memory, and neural circuit maturation, the dysregulation of synaptic plasticity is considered as a pathobiological feature of schizophrenia. The findings from our recently concluded studies indicate that there is an alteration in levels of synaptic plasticity markers such as neural cell adhesion molecule-1 (NCAM-1), Neurotropin-3 (NT-3) and Matrix-mettaloproteinase-9 (MMP-9) in schizophrenia patients. The objective of the present article is to review the role of markers of synaptic plasticity in schizophrenia. PubMed database (http;//www.ncbi.nlm.nih.gov/pubmed) was used to perform an extensive literature search using the keywords schizophrenia and synaptic plasticity. We conclude that markers of synaptic plasticity are altered in schizophrenia and may lead to complications of schizophrenia including cognitive dysfunction.

Prospects for Neurotrophic Factor-Based Early Intervention in Schizophrenia: Lessons Learned from the Effects of Antipsychotic Drugs on Cognition, Neurogenesis, and Neurotrophic Factors

Although reducing psychotic symptoms in schizophrenia has been a major focus of therapeutic interventions for decades, improving cognition is considered a better predictor of functional outcomes. However, the most commonly prescribed antipsychotic drugs (APDs) show only marginal beneficial effects on cognition in patients with schizophrenia. The neural mechanisms underlying cognitive disturbances in schizophrenia remain unknown that making drug development efforts very challenging. Since neurotrophic factors are the primary architects of neurogenesis, synaptic plasticity, learning, and memory, the findings from preclinical and clinical studies that assess changes in neurogenesis and neurotrophic factors and their relationship to cognitive performance in schizophrenia, and how these mechanisms might be impacted by APD treatment, may provide valuable clues in developing therapies to combat cognitive deficit in schizophrenia. Numerous evidence produced over the years suggests a deficit in a wide spectrum of neurotrophic factors in schizophrenia. Since schizophrenia is considered a neurodevelopmental disorder, early intervention with neurotrophic factors may be more effective in ameliorating the cognitive deficits and psychopathological symptoms associated with this pathology. In this context, results from initial clinical trials with neurotrophic factors and their future potential to improve cognition and psychosocial functioning in schizophrenia are discussed.

The Potential Use of Peripheral Blood Mononuclear Cells as Biomarkers for Treatment Response and Outcome Prediction in Psychiatry: A Systematic Review

BACKGROUND

Psychiatric disorders have a major impact on the global burden of disease while therapeutic interventions remain insufficient to adequately treat a large number of patients. Regrettably, the efficacy of several psychopharmacological treatment regimens becomes apparent only after 4-6 weeks, and at this point, a significant number of patients present as non-responsive. As such, many patients go weeks/months without appropriate treatment or symptom management. Adequate biomarkers for treatment success and outcome prediction are thus urgently needed.

OBJECTIVE

With this systematic review, we provide an overview of the use of peripheral blood mononuclear cells (PBMCs) and their signaling pathways in evaluating and/or predicting the effectiveness of different treatment regimens in the course of psychiatric illnesses. We highlight PBMC characteristics that (i) reflect treatment presence, (ii) allow differentiation of responders from non-responders, and (iii) prove predictive at baseline with regard to treatment outcome for a broad range of psychiatric intervention strategies.

REVIEW METHODS

A PubMed database search was performed to extract papers investigating the relation between any type of PBMC characteristic and treatment presence and/or outcome in patients suffering from severe mental illness. Criteria for eligibility were: written in English; psychiatric diagnosis based on DSM-III-R or newer; PBMC isolation via gradient centrifugation; comparison between treated and untreated patients via PBMC features; sample size ≥ n = 5 per experimental group. Papers not researching in vivo treatment effects between patients and healthy controls, non-clinical trials, and non-hypothesis-/data-driven (e.g., -omics designs) approaches were excluded.

DATA SYNTHESIS

Twenty-nine original articles were included and qualitatively summarized. Antidepressant and antipsychotic treatments were mostly reflected by intracellular inflammatory markers while intervention with mood stabilizers was evidenced through cell maturation pathways. Lastly, cell viability parameters mirrored predominantly non-pharmacological therapeutic strategies. As for response prediction, PBMC (subtype) counts and telomerase activity seemed most promising for antidepressant treatment outcome determination; full length brain-derived neurotrophic factor (BDNF)/truncated BDNF were shown to be most apt to prognosticate antipsychotic treatment.

CONCLUSIONS

We conclude that, although inherent limitations to and heterogeneity in study designs in combination with the scarce number of original studies hamper unambiguous identification, several PBMC characteristics-mostly related to inflammatory pathways and cell viability-indeed show promise towards establishment as clinically relevant treatment biomarkers.

Nerve Growth Factor in Alcohol Use Disorders

The nerve growth factor (NGF) belongs to the family of neurotrophic factors. Initially discovered as a signaling molecule involved in the survival, protection, differentiation, and proliferation of sympathetic and peripheral sensory neurons, it also participates in the regulation of the immune system and endocrine system. NGF biological activity is due to the binding of two classes of receptors: the tropomyosin-related kinase A (TrkA) and the low-affinity NGF pan-neurotrophin receptor p75. Alcohol Use Disorders (AUD) are one of the most frequent mental disorders in developed countries, characterized by heavy drinking, despite the negative effects of alcohol on brain development and cognitive functions that cause individual’s work, medical, legal, educational, and social life problems. In addition, alcohol consumption during pregnancy disrupts the development of the fetal brain causing a wide range of neurobehavioral outcomes collectively known as fetal alcohol spectrum disorders (FASD). The rationale of this review is to describe crucial findings on the role of NGF in humans and animals, when exposed to prenatal, chronic alcohol consumption, and on binge drinking.

Exploring the role of oxidative stress, fatty acids and neurotrophins in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) constitutes an unfavorable intrauterine environment for embryonic and feto-placental development. Women with GDM are at higher risk for materno-fetal complications and placental abnormalities. The placenta acts as an interface between the maternal and fetal circulations and also plays an important role in protecting the fetus from adverse effects of maternal metabolic conditions. One of the earliest abnormalities observed in GDM pregnancies is increased oxidative stress in the placenta which affects fetal development. Imbalances in maternal nutrition particularly long-chain polyunsaturated fatty acid (LCPUFA) intake and/or metabolism lead to increased oxidative stress. Reports indicate that oxidative stress and LCPUFA such as docosahexaenoic acid affect the levels of neurotrophins. The present review aims to provide insights into a mechanistic link between oxidative stress, LCPUFA and neurotrophin in the placenta in women with GDM and its implications for neurodevelopmental outcomes in children.

Vagus nerve stimulation and Neurotrophins: a biological psychiatric perspective

Since 2004, vagus nerve stimulation (VNS) has been used in treatment-resistant or treatment-intolerant depressive episodes. Today, VNS is suggested as possible therapy for a larger spectrum of psychiatric disorders, including schizophrenia, obsessive compulsive disorders, and panic disorders. Despite a large body of literature supports the application of VNS in patients' treatment, the exact mechanism of action of VNS remains not fully understood. In the present study, the major knowledges on the brain areas and neuronal pathways regulating neuroimmune and autonomic response subserving VNS effects are reviewed. Furthermore, the involvement of the neurotrophins (NTs) Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) in vagus nerve (VN) physiology and stimulation is revised. The data on brain NGF/BDNF synthesis and in turn on the activity-dependent plasticity, connectivity rearrangement and neurogenesis, are presented and discussed as potential biomarkers for optimizing stimulatory parameters for VNS. A vagus nerve-neurotrophin interaction model in the brain is finally proposed as a working hypothesis for future studies addressed to understand pathophysiology of psychiatric disturbance.

Nerve Growth Factor Serum Levels Are Associated With Regional Gray Matter Volume Differences in Schizophrenia Patients

Numerous neuroimaging studies have revealed structural brain abnormalities in schizophrenia patients. There is emerging evidence that dysfunctional nerve growth factor (NGF) signaling may contribute to structural brain alterations found in these patients. In this pilot study, we investigated whether there was a correlation between NGF serum levels and gray matter volume (GMV) in schizophrenia patients. Further, we investigated whether there was an overlap between the correlative findings and cross-sectional GMV differences between schizophrenia patients (n = 18) and healthy controls (n = 19). Serum NGF was significantly correlated to GMV in the left prefrontal lobe, the left midcingulate cortex, and the brainstem in schizophrenia patients. However, we did not find any correlations of NGF serum levels with GMV in healthy controls. Schizophrenia patients showed smaller GMV than healthy controls in brain regions located in the bilateral limbic system, bilateral parietal lobe, bilateral insula, bilateral primary auditory cortex, left frontal lobe, and bilateral occipital regions. In a conjunction analysis, GMV in the left midcingulate cortex (MCC) appears negatively correlated to NGF serum levels in the group of schizophrenia patients and also to be reduced compared to healthy controls. These results suggest an increased vulnerability of schizophrenia patients to changes in NGF levels compared to healthy controls and support a role for NGF signaling in the pathophysiology of schizophrenia. As our pilot study is exploratory in nature, further studies enrolling larger sample sizes will be needed to further corroborate our findings and to investigate the influence of additional covariates.

The neurobiological hypothesis of neurotrophins in the pathophysiology of schizophrenia: A meta-analysis

BACKGROUND

Schizophrenia is associated with patterns of aberrant neurobiological circuitry. The disease complexity is mirrored by multiple biological interactions known to contribute to the disease pathology. One potential contributor is the family of neurotrophins which are proteins involved in multiple functional processes in the nervous system, with crucial roles in neurodevelopment, synaptogenesis and neuroplasticity. With these roles in mind, abnormal neurotrophin profiles have been hypothesized to contribute to the pathology of schizophrenia.

METHODS

We performed a systematic review and a meta-analysis to scrutinize the neurobiological hypothesis of neurotrophins in schizophrenia, examining the correlation between peripheral levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3) and neurotrophin 4/5 (NT-4/5) associated with schizophrenia.

RESULTS

Fifty-two studies were reviewed and twenty-two studies were included in this meta-analysis. Using a random effects model, we confirmed that decreased levels of neurotrophins (BDNF, NGF and NT-4/5) were associated with schizophrenia (Hedges's g = -0.846; SE = 0.058; 95% confidence interval: -0.960 to -0.733; Z-value = -14.632; p-value = 0.000). Subgroup analysis indicated that neurotrophin levels are significantly decreased in both medicated and drug-näive patients. Meta-regression of continuous variables such as mean age, duration of illness and PANSS total score did not show significant effects (p > 0.05) in relation to neurotrophins levels.

DISCUSSION

We confirm that decreased peripheral neurotrophin levels are significantly associated with schizophrenia, thereby confirming the neurobiological hypothesis of neurotrophins in schizophrenia. Low levels of neurotrophins in peripheral blood of patients with schizophrenia may explain, in part, the pathophysiology of schizophrenia.

A meta-analysis of peripheral blood nerve growth factor levels in patients with schizophrenia

Neurotrophins particularly brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are crucial modulators in the neurodevelopment and maintenance of central and peripheral nervous systems. Neurotrophin hypothesis of schizophrenia (SCZ) postulated that the changes in the brains of SCZ patients are the result of disturbances of developing processes involving neurotrophic factors. This hypothesis was mainly supported by the abnormal regulation of BDNF in SCZ, especially the decreased peripheral blood BDNF levels in SCZ patients validated by several meta-analyses. However, the regulation of NGF in SCZ remains unclear because of the inconsistent findings from the clinical studies. Therefore, we undertook, to the best of our knowledge, the first systematic review with a meta-analysis to quantitatively summarize the peripheral blood NGF data in SCZ patients compared with healthy control (HC) subjects. A systematic search of Pubmed, PsycINFO and Web of Science identified 13 articles encompassing a sample of 1693 individuals for the meta-analysis. Random-effects meta-analysis showed that patients with SCZ had significantly decreased peripheral blood levels of NGF when compared with the HC subjects (Hedges's g=-0.633, 95% confidence interval (CI)=-0.948 to -0.318, P<0.001). Subgroup analyses revealed reduced NGF levels both in serum (Hedges's g=-0.671, 95% CI=-1.259 to -0.084, P=0.025) and plasma (Hedges's g=-0.621, 95% CI=-0.980 to -0.261, P<0.001) of the patients, and in drug-free (Hedges's g=-0.670, 95% CI=-1.118 to -0.222, P=0.003) and medicated (Hedges's g=-0.357, 95% CI=-0.592 to -0.123, P=0.003) patients with SCZ. Furthermore, meta-regression analyses showed that age, gender and sample size had no moderating effects on the outcome of the meta-analysis, whereas disease severity might be a confounding factor for the meta-analysis. These results demonstrated that patients with SCZ are accompanied by the decreased peripheral blood NGF levels, strengthening the clinical evidence of an abnormal neurotrophin profile in the patients with SCZ.

Peripheral blood nerve growth factor levels in major psychiatric disorders

Nerve growth factor (NGF) plays crucial roles in promoting neural growth and survival, and mediating synaptic and morphological plasticity. Several studies investigated the correlation between peripheral NGF levels and major psychiatric disorders, including schizophrenia (SCZ), major depressive disorder (MDD) and bipolar disorder (BPD); however, the findings were inconsistent. This meta-analysis sought to investigate blood NGF levels in patients with psychiatric disorders compared with healthy subjects and examined potential effects of blood fraction, medication and disease status. A total of 21 eligible studies, encompassing 1342 patients suffering from psychiatric disorders and 1225 healthy subjects, were enrolled in the present meta-analysis. No obvious publication bias was observed either for SCZ, MDD or BPD by the Begg's test (P > 0.05). Random-effects meta-analysis showed that SCZ (Z = 2.14, P = 0.033, SMD = -1.08, 95% CI = -2.07 to -0.09) and MDD (Z = 2.57, P = 0.010, SMD = -0.61, 95% CI = -1.08 to -0.14) patients had significantly reduced NGF levels, compared with healthy controls. Notably, this decrease was enhanced in un-medicated patients of SCZ (P = 0.004) and medicated or chronic patients of MDD (P < 0.001). No significant difference of NGF levels was observed between BPD patients and controls (P > 0.05). These results supported an association between the reduction of NGF levels and psychiatric disorders. It remains unclear whether the change of NGF levels is a prerequisite for its function in psychiatric disorders development or merely an epiphenomenon unrelated to the pathophysiologic mechanisms.

Possible biomarkers modulating haloperidol efficacy and/or tolerability

Haloperidol (HP) is widely used in the treatment of several forms of psychosis. Despite of its efficacy, HP use is a cause of concern for the elevated risk of adverse drug reactions. adverse drug reactions risk and HP efficacy greatly vary across subjects, indicating the involvement of several factors in HP mechanism of action. The use of biomarkers that could monitor or even predict HP treatment impact would be of extreme importance. We reviewed the elements that could potentially be used as peripheral biomarkers of HP effectiveness. Although a validated biomarker still does not exist, we underlined the several potential findings (e.g., about cytokines, HP metabolites and genotypic biomarkers) which could pave the way for future research on HP biomarkers.

BDNF and NGF Signalling in Early Phases of Psychosis: Relationship With Inflammation and Response to Antipsychotics After 1 Year

Previous studies have indicated systemic deregulation of the proinflammatory or anti-inflammatory balance in individuals with first-episode psychosis (FEP) that persists 12 months later. To identify potential risk/protective factors and associations with symptom severity, we assessed possible changes in plasma levels of neurotrophins (brain-derived neurotrophic factor [BDNF] and nerve growth factor [NGF]) and their receptors in peripheral blood mononuclear cells (PBMCs). Expression of the 2 forms of BDNF receptors (active TrkB-FL and inactiveTrkB-T1) in PBMCs of FEP patients changed over time, TrkB-FL expression increasing by 1 year after diagnosis, while TrkB-T1 expression decreased. The TrkB-FL/TrkB-T1 ratio (hereafter FL/T1 ratio) increased during follow-up in the nonaffective psychosis group only, suggesting different underlying pathophysiological mechanisms in subgroups of FEP patients. Further, the expression of the main NGF receptor, TrkA, generally increased in patients at follow-up. After adjusting for potential confounders, baseline levels of inducible isoforms of nitric oxide synthase, cyclooxygenase, and nuclear transcription factor were significantly associated with the FL/T1 ratio, suggesting that more inflammation is associated with higher values of this ratio. Interestingly, the FL/T1 ratio might have a role as a predictor of functioning, a regression model of functioning at 1 year suggesting that the effect of the FL/T1 ratio at baseline on functioning at 1 year depended on whether patients were treated with antipsychotics. These findings may have translational relevance; specifically, it might be useful to assess the expression of TrkB receptor isoforms before initiating antipsychotic treatment in FEPs.

The neurobiology of relapse in schizophrenia

Dopamine's proposed role in psychosis proved a starting point in our understanding of the neurobiology of relapse, fitting given the central role positive symptoms play. This link is reflected in early work examining neurotransmitter metabolite and drug (e.g. amphetamine, methylphenidate) challenge studies as a means of better understanding relapse and predictors. Since, lines of investigation have expanded (e.g. electrophysiological, immunological, hormonal, stress), an important step forward if relapse per se is the question. Arguably, perturbations in dopamine represent the final common pathway in psychosis but it is evident that, like schizophrenia, relapse is heterogeneous and multidimensional. In understanding the neurobiology of relapse, greater gains are likely to be made if these distinctions are acknowledged; for example, efforts to identify trait markers might better be served by distinguishing primary (i.e. idiopathic) and secondary (e.g. substance abuse, medication nonadherence) forms of relapse. Similarly, it has been suggested that relapse is 'neurotoxic', yet individuals do very well on clozapine after multiple relapses and the designation of treatment resistance. An alternative explanation holds that schizophrenia is characterized by different trajectories, at least to some extent biologically and/or structurally distinguishable from the outset, with differential patterns of response and relapse. Just as with schizophrenia, it seems naïve to conceptualize the neurobiology of relapse as a singular process. We propose that it is shaped by the form of illness and in place from the outset, modified by constitutional factors like resilience, as well as treatment, and confounded by secondary forms of relapse.

QTL replication and targeted association highlight the nerve growth factor gene for nonverbal communication deficits in autism spectrum disorders

Autism Spectrum Disorder (ASD) has a heterogeneous etiology that is genetically complex. It is defined by deficits in communication and social skills and the presence of restricted and repetitive behaviors. Genetic analyses of heritable quantitative traits that correlate with ASD may reduce heterogeneity. With this in mind, deficits in nonverbal communication (NVC) were quantified based on items from the Autism Diagnostic Interview Revised. Our previous analysis of 228 families from the Autism Genetics Research Exchange (AGRE) repository reported 5 potential quantitative trait loci (QTL). Here we report an NVC QTL replication study in an independent sample of 213 AGRE families. One QTL was replicated (P<0.0004). It was investigated using a targeted-association analysis of 476 haplotype blocks with 708 AGRE families using the Family Based Association Test (FBAT). Blocks in two QTL genes were associated with NVC with a P-value of 0.001. Three associated haplotype blocks were intronic to the Nerve Growth Factor (NGF) gene (P=0.001, 0.001, 0.002), and one was intronic to KCND3 (P=0.001). Individual haplotypes within the associated blocks drove the associations (0.003, 0.0004 and 0.0002) for NGF and 0.0001 for KCND3. Using the same methods, these genes were tested for association with NVC in an independent sample of 1517 families from an Autism Genome Project (AGP). NVC was associated with a haplotype in an adjacent NGF block (P=0.0005) and one 46 kb away from the associated block in KCND3 (0.008). These analyses illustrate the value of QTL and targeted association studies for genetically complex disorders such as ASD. NGF is a promising risk gene for NVC deficits.

The role of NGF and IL-2 serum level in assisting the diagnosis in first episode schizophrenia

Development of reliable diagnostic bio-markers for schizophrenia remains a diagnostic challenge. Serum NGF and IL-2 were analyzed to examine the diagnostic efficiency and predictive capability of these two biomarkers in relation to schizophrenia diagnosis. Thirty neuroleptic naïve subjects with first-episode schizophrenia, thirty patients with major depressive disorder (MDD) and twenty-eight healthy control subjects participated in the study. One-way ANOVA demonstrated significantly lower serum IL-2 and NGF among schizophrenic patients and patients with MDD compared with healthy controls. Receiver operating characteristic (ROC) curve analysis was used to ascertain diagnostic efficiency of serum IL-2 and NGF levels. Area under the ROC curve (AUC) revealed a high level of differentiation between schizophrenic patients and healthy controls for both IL-2 and NGF serum concentrations. Diagnostic efficiency of combined NGF and IL-2 serum levels was also high in schizophrenic patients compared with healthy controls. Serum NGF and IL-2 are promising as potential screening or diagnostic biomarkers for schizophrenia and may be a useful adjunct for clinical assessment.

The cannabinergic system is implicated in the upregulation of central NGF protein by psychotropic drugs

RATIONALE

Studies on the regulation of nerve growth factor (NGF) levels by psychotropics are limited in scope and the mechanism(s) remain elusive which merit further elucidation.

OBJECTIVES

We aimed to perform a more comprehensive investigation on the possible effects of pharmacologically heterogeneous groups of psychotropic drugs on NGF contents in the brain regions involved in the modulation of emotions. As a mechanistic approach, we looked at the role of the cannabinergic system which is linked to depression and/or antidepressant effect and appears to interact with neurotrophin signaling.

METHODS

Following psychotropic treatment, NGF or endocannabinoid (eCB) contents were quantified by Bio-Rad protein assay and isotope-dilution liquid chromatography/mass spectrometry, respectively. In case of any significant change, the effects of pretreatment with the CB(1) receptor neutral antagonist AM4113 were investigated.

RESULTS

Single injection of nortriptyline, isocarboxazid, citalopram, diazepam, risperidone (2.5, 5, and 10 mg/kg, each), and fluphenazine (0.25, 0.5, and 1 mg/kg) into rats did not alter NGF or eCB contents. Following 4-week treatment, all drugs except diazepam elevated NGF or eCB levels in dose-dependent and brain region-specific fashion. Pretreatment with the highest dose of AM4113 (5.6 mg/kg) prevented psychotropic-induced NGF or eCB elevation. AM4113 had no effect by itself.

CONCLUSIONS

The cannabinergic system is implicated in the mechanisms of action of certain psychotropic drugs including the upregulation of brain NGF levels. This provides a better understanding of the pathophysiological mechanisms underlying neuropsychiatric disorders, leading to novel drug design.

Impaired nerve growth factor homeostasis in patients with bipolar disorder

OBJECTIVE

Neuro-trophins are critically involved in neuro-plasticity, the impairment of which is a major role-player in bipolar disorder (BD), and their altered levels have been recently advocated in the patho-physiology of this affective malady. The aim of this study, therefore, was to evaluate the plasma levels of nerve growth factor (NGF) in BD patients in comparison with control subjects.

METHODS

Forty-nine BD type-I individuals (30 in mania and 19 in euthymia) and 36 healthy controls were assessed by Mini-plus, Young mania and Hamilton depression rating scales. NGF levels were detected by ELISA.

RESULTS

Plasma NGF concentrations were decreased in BD patients when compared to that seen with controls. BD individuals in mania had lower NGF levels than euthymic patients or controls. NGF levels were negatively correlated with the severity of mania.

CONCLUSIONS

This is the first study to evaluate NGF levels in BD patients, providing further support to the hypothesis of impaired neuro-plasticity in BD. These data also suggest that NGF measurement could be used for the biological marker for manic state.

Vitamin D: a potential role in reducing suicide risk?

Suicide attempts are known to peak in the spring, overlapping with the time of year when 25-hydroxyvitamin D [25(OH)D] levels are at their nadir in the northern hemisphere because of negligible skin production of vitamin D owing to low levels of ultraviolet B radiation. Low levels of 25(OH)D, the vitamin D metabolite used to diagnose vitamin D deficiency, have been associated with certain pro-suicidal factors such as exacerbation of depression, anxiety, psychosis, and certain medical conditions. Therefore, we hypothesize that vitamin D deficiency could also be associated with increased risk of completed suicides. Here, we briefly review the literature on vitamin D, its deficiency, and its reported association with certain risk factors for suicide.

Converging evidence of blood-based biomarkers for schizophrenia: an update

This chapter has carried out a review of the literature and combined this with the results of in-house studies to identify candidate blood-based biomarkers for schizophrenia and antipsychotic drug response. Literature searches retrieved 185 publications describing a total of 273 schizophrenia biomarkers identified in serum and/or plasma. Examination of seven in-house multicenter studies resulted in the identification of 137 serum/plasma biomarkers. Taken together, the findings suggested an ongoing immunological and inflammatory process in schizophrenia. This was accompanied by altered cortisol levels which suggested activated stress response and altered hypothalamic-pituitary-adrenal axis function in these patients. The authors conclude that such biomarkers may prove useful as additional parameters for characterizing specific immune and/or metabolic or hormonal subsystems in schizophrenia and might, therefore, facilitate the development of future patient stratification and personalized medicine strategies.

Role of the central cholinergic system in the therapeutics of schizophrenia

The therapeutic agents currently used to treat schizophrenia effectively improve psychotic symptoms; however, they are limited by adverse effects and poor efficacy when negative symptoms of the illness and cognitive dysfunction are considered. While optimal pharmacotherapy would directly target the neuropathology of schizophrenia neither the underlying neurobiological substrates of the behavioral symptoms nor the cognitive deficits have been clearly established. Abnormalities in the neurotransmitters dopamine, serotonin, glutamate, and GABA are commonly implicated in schizophrenia; however, it is not uncommon for alterations in the brain cholinergic system (e.g., choline acetyltransferase, nicotinic and muscarinic acetylcholine receptors) to also be reported. Further, there is now considerable evidence in the animal literature to suggest that both first and second generation antipsychotics (when administered chronically) can alter the levels of several cholinergic markers in the brain as well as impair memory-related task performance. Given the well-established importance of central cholinergic neurons to information processing and cognition, it is important that cholinergic function in schizophrenia be further elucidated and that the mechanisms of the chronic effects of antipsychotic drugs on this important neurotransmitter system be identified. A better understanding of these mechanisms would be expected to facilitate optimal treatment strategies for schizophrenia as well as the identification of novel therapeutic targets. In this review, the following topics are discussed: 1) the central cholinergic system in schizophrenia 2) effects of antipsychotic drugs on central cholinergic neurons 3) important neurotrophins in schizophrenia, especially those that support central cholinergic neurons; 4) novel strategies to optimize the therapeutics of schizophrenia via the use of cholinergic compounds as primary (i.e., antipsychotic) treatments as well as adjunctive, pro-cognitive agents.

Decreased BDNF in patients with antipsychotic naïve first episode schizophrenia

OBJECTIVE

Brain-derived neurotrophic factor (BDNF) is a key factor known to mediate neuronal proliferation, differentiation, survival and response to stress. Decreases in BDNF levels have been reported in schizophrenia, but studies in treatment naïve patients are few. Herein we report on serum BDNF levels in a series of patients with first-episode treatment naïve psychoses in comparison to age matched healthy controls.

METHOD

Fasting serum BDNF levels were measured in 41 patients with treatment naive first episode psychosis (24 with schizophrenia, schizoaffective disorder or schizophreniform disorder, and 17 with non-schizophrenia psychotic disorders) and 41 age-matched healthy controls.

RESULTS

A three group analyses of covariance (ANCOVA) showed a diagnosis effect (p=.038) in which patients with schizophrenia had lesser serum BDNF levels than patient with non-schizophrenia psychosis, who in turn had lesser BDNF levels than matched healthy controls. Planned two-group ANCOVAs suggested that patients with schizophrenia had lower serum BDNF level than matched controls (p=.016), whereas patients with non-schizophrenia psychosis did not differ from controls. There were no age effects on BDNF, but there was a trend (p=.08) for a gender by group interaction with greater reductions in female patients with schizophrenia. The BDNF levels did not correlate with magnitude of smoking, body mass index, severity of positive and negative symptoms or overall functioning.

CONCLUSIONS

Serum BDNF may be reduced at the onset of psychosis but its role in the pathogenesis of schizophrenia remains unclear. Elucidating the role of BDNF in schizophrenia and related psychotic disorders may provide an important therapeutic target. Further studies are also needed to examine if patients with schizophrenia have more pronounced reductions in BDNF than those with affective psychosis.

Reduced NGF serum levels and abnormal P300 event-related potential in first episode schizophrenia

Nerve growth factor (NGF) plays a crucial role in central nervous system neuron plasticity. Low levels of serum NGF in schizophrenic patients suggest that the neurotrophin contributes to the pathogenesis of the disease. NGF is also thought to alter characteristics of event-related brain potential (ERP) components. The auditory-evoked P300 ERP component, considered an index of brain activity, has reduced amplitude in acute and chronic schizophrenia. This study evaluated the relationship among serum NGF levels, P300 characteristics, and Positive and Negative Symptom Scale (PANSS) scores in first episode, neuroleptic naive schizophrenic patients (N=30) and healthy controls (N=28). Serum NGF was measured by ELISA and P300 elicited using auditory oddball paradigm. Compared to control subjects, schizophrenic patients had significantly reduced serum NGF (p<0.001) and lower P300 amplitudes at Fz (p=0.003). Additionally, there was a positive correlation between serum NGF serum and P300 amplitude at Fz. No correlation was found between serum NGF or P300 characteristics and PANSS scores. These results suggest that the effects of NGF in schizophrenia are related not only to regulation of neurodevelopment, but also to the electrophysiological characteristics of nerve growth factor.

Reduced serum BDNF levels in patients with chronic schizophrenic disorder in relapse, who were treated with typical or atypical antipsychotics

Brain-derived neurotrophic factor signals and dopaminergic function in the brain are strongly associated, and research on BDNF in schizophrenia may enhance our insights on the pathophysiological mechanisms of this disease. In the present study we aimed to investigate the possible association between serum BDNF levels and schizophrenic relapses and the possible differential effects of treatment with typical and atypical antipsychotics on serum BDNF levels in the same group of patients. We measured serum BDNF levels in 47 patients with schizophrenia during a relapse and again 6 weeks after administration of antipsychotic treatment (14 on risperidone, 18 on haloperidol, 10 on olanzapine and five on amisulpride) and in 44 healthy volunteers. Patients with schizophrenia showed reduced serum BDNF levels in relation to healthy volunteers at study entry. No significant differences were revealed in BDNF serum levels after 6 weeks of antipsychotic treatment in the patients compared to their own levels at study entry. However, serum BDNF was significantly increased in the subgroup receiving olanzapine compared to the other antipsychotics. Our findings may indicate a differential effect of olanzapine on BDNF levels compared to haloperidol, risperidone, and amisulpride.

Reduced cerebrospinal fluid and plasma nerve growth factor in drug-naïve psychotic patients

Impaired expression and function of several major neurotrophic factors such as nerve growth factor (NGF) has been proposed to contribute to the neurodevelopmental pathology of schizophrenia. However, the evidence in the majority of studies is based on variable and inconsistent levels of plasma NGF in diverse populations of early psychosis or medicated patients with chronic schizophrenia. We report here the first study comparing NGF levels in cerebrospinal fluid (CSF) and plasma from a unique patient cohort (unmedicated, early psychotic patients with similar racial and dietary patterns) and matched healthy controls. Significantly lower levels of NGF in both CSF (p=0.038) and plasma (p=0.002) were observed in drug-naïve first-episode psychosis patients as compared to controls. The levels of NGF in the CSF correlated (p=0.05) to the plasma values in controls. The data on plasma NGF confirm the reported deficits of NGF in drug-naïve first-episode psychosis. The reduced levels first time observed here may have important implications to repeatedly reported neurobiological and clinical deficits which are discussed.

Genome-wide expression analysis of peripheral blood identifies candidate biomarkers for schizophrenia

The aim of this study was to analyze gene expression in blood of patients with newly-diagnosed schizophrenia during their first psychotic episode and subsequent remission. Whole blood samples were obtained from 32 untreated patients presenting with their first psychotic episode suggestive of schizophrenia and 32 age- and gender-matched controls. Using Affymetrix micoarrays, we identified significantly altered expression of 180 gene probes in psychotic patients compared to controls. A subset of four significantly changed genes was further confirmed with QRT-PCR. The following genes were significantly altered in patients: glucose transporter, SLC2A3 (p<0.001) and actin assembly factor DAAM2 (p<0.001) were increased, whereas translation, zinc metallopeptidase, neurolysin 1 and myosin C were significantly decreased (p<0.05). Expression of these candidate markers was also analyzed in a longitudinal study (12-24 months) in 12 patients who achieved full remission. Interestingly, expression of DAAM2 returned to control levels in patients who were in remission after their first psychotic episode, suggesting that its expression correlates with diseases progression and/or response to treatment. In summary, we identified changes of gene expression from peripheral blood which might help discriminate patients with schizophrenia from controls. While these results are promising, especially for DAAM2 whose polymorphic variants have been found significantly associated with schizophrenia, it will be important to analyze larger cohorts of patients in order to firmly establish changes in gene expression as blood markers of schizophrenia.

Increased serum S100B levels in chronic schizophrenic patients on long-term clozapine or typical antipsychotics

S100B is a calcium-binding protein, mainly produced and secreted by astrocytes, and it mediates the interaction among glial cells and between glial cells and neurons. Recently, several studies have shown increased serum 100B levels in patients with schizophrenia, suggesting that S100B might be relevant to the pathophysiology of schizophrenia. To examine the potentially differential effect of clozapine compared to typical antipsychotics on serum S100B and the relationship between S100B levels and psychopathology in patients with schizophrenia, 63 physically healthy patients with schizophrenia were compared with 50 age-, sex-matched normal controls. The psychopathology of patients was assessed by the Positive and Negative Syndrome Scale (PANSS). Serum S100B levels were measured by sandwich ELISA. The results showed that S100B levels were significantly elevated in chronic patients with schizophrenia than in healthy controls (p<0.0001). As compared with healthy controls, there was a significant increase in S100B levels in patients treated with both clozapine and typical antipsychotics (both p<0.0001). However, no significant difference in S100B was found between patients treated with clozapine and typical antipsychotic subgroups (p>0.05). Furthermore, there was no significant correlation between S100B and standardized drug doses or the duration of taking neuroleptic medications (both p>0.05). In addition, no significant correlation was observed between S100B and PANSS total score and its subscale scores (all >0.05). These findings suggest that serum S100B levels in chronic schizophrenia under antipsychotic medication may be increased, suggesting that a dysfunction of astrocytes and/or oligodendrocytes may play a role in the pathogenesis of schizophrenia. Long term treatment with both typical and atypical antipsychotics may produce similar effects on the S100B serum levels, which however remains to be characterized in a large sample of first-episode, medication-naïve patients with schizophrenia using a longitudinal design.

Gestational vitamin D deficiency: long-term effects on the brain

Gestational vitamin D deficiency causes permanent changes in the developing rat brain. Not only does it alter brain gene and protein expression, deficiency disrupts the balance between neuronal stem cell proliferation and programmed cell death in the offspring. These data are particularly relevant in light of new work showing a high prevalence of vitamin D deficiency in humans.

Neuroprotective effect of atypical antipsychotics in cognitive and non-cognitive behavioral impairment in animal models

Antipsychotic drugs are divided into two groups: typical and atypical. Recent clinical studies show atypical antipsychotics have advantages over typical antipsychotics in a wide variety of neuropsychiatric conditions, in terms of greater efficacy for positive and negative symptoms, beneficial effects on cognitive functioning, and fewer extra pyramidal side effects in treating schizophrenia. As such, atypical antipsychotics may be effective in the treatment of depressive symptoms associated with psychotic and mood disorders, posttraumatic stress disorder and psychosis in Alzheimer disease. In this paper, we describe the effects and potential neurochemical mechanisms of action of atypical antipsychotics in several animal models showing memory impairments and/or non-cognitive behavioral changes. The data provide new insights into the mechanisms of action of atypical antipsychotics that may broaden their clinical applications.

Differential effects of ziprasidone and haloperidol on immobilization stress-induced mRNA BDNF expression in the hippocampus and neocortex of rats

Recent in vivo and in vitro experiments have demonstrated that second-generation antipsychotic drugs (SGAs) might have neuroprotective effects. Ziprasidone is a SGA that is efficacious in the treatment of schizophrenia. In this study, we sought to analyze the effects of ziprasidone on the expression of the neuroprotective protein brain-derived neurotrophic factor (BDNF) in the rat hippocampus and neocortex, with or without immobilization stress. The effect of ziprasidone (2.5mg/kg) on the expression of BDNF mRNA was determined by in situ hybridization in tissue sections from the rat hippocampus and neocortex. Haloperidol (1.0mg/kg) was used for comparison. Haloperidol strongly decreased the expression of BDNF mRNA in both the hippocampal and cortical regions, with or without immobilization stress (p<0.01). In contrast, the administration of ziprasidone significantly attenuated the immobilization stress-induced decrease in BDNF mRNA expression in the rat hippocampus and neocortex (p<0.01). Ziprasidone exhibited differential effects on BDNF mRNA expression in the rat hippocampus and neocortex. These results suggest that ziprasidone might have a neuroprotective effect by recovering stress-induced decreases in BDNF mRNA expression.

Effects of psychostimulants on neurotrophins implications for psychostimulant-induced neurotoxicity

It is well documented that psychostimulants may alter neuronal function and neurotransmission in the brain. Although the mechanism of psychostimulants is still unknown, it is known that these substances increase extracellular level of several neurotransmitters including dopamine (DA), serotonin, and norepinephrine by competing with monoamine transporters and can induce physical tolerance and dependence. In addition to this, recent findings also suggest that psychostimulants may damage brain neurons through mechanisms that are still under investigation. In the recent years, it has been demonstrated that almost all psychostimulants are able to affect a class of proteins, called neurotrophins, in the peripheral and central nervous system (CNS). Neurotrophins, such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), have relevant action on neurons involved in psychostimulant action, such as DA and serotonergic neurons, and can play dual roles: first, in neuronal survival and death, and, second, in activity-dependent plasticity. In this review, we will focalize on the effects of psychostimulants on this class of proteins, which may be implicated, at least in part, in the mechanism of the psychostimulant-induced neurotoxicity. Moreover, since altered neurotrophins may participate in the pathogenesis of psychiatric disorders and psychiatric disorders are common in drug users, one plausible hypothesis is that psychostimulants can cause psychosis through interfering with neurotrophins synthesis and utilization by CNS neurons.

Chronic heroin and cocaine abuse is associated with decreased serum concentrations of the nerve growth factor and brain-derived neurotrophic factor

Chronic cocaine and heroin users display a variety of central nervous system (CNS) dysfunctions including impaired attention, learning, memory, reaction time, cognitive flexibility, impulse control and selective processing. These findings suggest that these drugs may alter normal brain functions and possibly cause neurotoxicity. Neurotrophins are a class of proteins that serve as survival factors for CNS neurons. In particular, nerve growth factor (NGF) plays an important role in the survival and function of cholinergic neurons while brain-derived neurotrophic factor (BDNF) is involved in synaptic plasticity and in the maintenance of midbrain dopaminergic and cholinergic neurons. In the present study, we measured by enzyme-linked immunosorbent assay (ELISA) the NGF and BDNF levels in serum of three groups of subjects: heroin-dependent patients, cocaine-dependent patients and healthy volunteers. Our goal was to identify possible change in serum neurotrophins in heroin and cocaine users. BDNF was decreased in heroin users whereas NGF was decreased in both heroin and cocaine users. These findings indicate that NGF and BDNF may play a role in the neurotoxicity and addiction induced by these drugs. In view of the neurotrophin hypothesis of schizophrenia the data also suggest that reduced level of neurotrophins may increase the risk of developing psychosis in drug users.

Neurotrophins and schizophrenia

Neurotrophins have established roles in neuronal development, synaptogenesis, and response to stress/anxious stimuli. Moreover, these agents are neuromodulators of monoaminergic, GABAergic, and cholinergic systems. Amidst a growing appreciation of the developmental neurobiology of schizophrenia--as well as the propensity for progressive brain changes--there is emergent information on abnormalities in the expression of neurotrophins in schizophrenia. This article reviews the literature on neurotrophins and schizophrenia. A schema for understanding the neurobiology of relapse in schizophrenia is offered.

Personalized treatment with atypical antipsychotic medications

The considerable pharmacologic differences among atypical antipsychotic agents and the specific clinical circumstances of individual patients with psychiatric illness require the availability of a full range of agents in this class. Restrictions in the availability of atypical agents may prove to be counterproductive, both clinically and economically. Elderly individuals and those from minority groups may be particularly disadvantaged by restrictions placed on these agents. Additional clinical studies in large populations with different forms of schizophrenia and varied clinical histories are required to determine the appropriateness of specific atypical agents in patient subgroups. Advances in knowledge of the molecular genetics of schizophrenia and the receptor properties of individual drugs will help the clinician determine which drug and dosage are best for each individual patient. This will eventually replace the "hit or miss" process that characterizes current practice. Because of variations in response to atypical agents, the clinical vulnerability of patients with psychiatric illness, the difficulties they have in adapting to changes and adhering to medication regimens, and our poor understanding of the molecular basis of schizophrenia and its treatment, prescription insurance plans should provide access to a broad range of atypical agents.

The case for long-acting antipsychotic agents in the post-CATIE era

OBJECTIVE

Long-acting antipsychotic agents were developed to promote treatment compliance in patients requiring maintenance treatment for schizophrenia.

METHOD

An analysis of the impact of non-compliance on treatment outcomes in schizophrenia and the advantages and disadvantages of long-acting antipsychotics.

RESULTS

Partial or total non-compliance with oral antipsychotics remains widespread and is associated with significant increases in the risk of relapse, rehospitalization, progressive brain tissue loss and further functional deterioration. Long-acting agents have the potential to address issues of all-cause discontinuation and poor compliance. The development of the first long-acting atypical antipsychotic, which appears to be effective and well tolerated, should further improve the long-term management of schizophrenia.

CONCLUSION

Long-acting agents represent a valuable tool for the management of schizophrenia and merit wider use, especially in light of emerging literature regarding the neuroprotective advantages of atypical antipsychotics over conventional agents in terms of regenerating brain tissue during maintenance therapy.

Exposure in fetus of methylazoxymethanol in the rat alters brain neurotrophins' levels and brain cells' proliferation

Changes during gestation have been shown to induce brain maldevelopment associated with changes in neurotrophins as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neuropsychiatric disorders in humans. A rat model of altered prenatal brain development resembling the onset of schizophrenia has been obtained by administering in fetus methylazoxymethanol (MAM) at gestational day 12 which impairs the growth of limbic pathways between the entorhinal cortex and the hippocampus. Using the MAM model we studied in young rats the brain levels of both NGF/BDNF and their main receptors, TrkA/TrkB, to investigate whether or not changes in neurotrophins could affect the presence of brain BrdU positive cells. We found increased NGF and BDNF protein levels, associated with elevated TrkA and TrkB expression, in the hippocampus, entorhinal cortex, olfactory lobes and subventricular zone (SVZ), brain areas playing a key role in the production and migration of new dividing cells. We also found higher levels of BrdU positive cells in the SVZ and hippocampus but not a significant potentiation in the entorhinal cortex and olfactory lobes. All together the findings indicate that prenatal MAM exposure in young rats may elicit both neurotrophins' elevation and cell proliferation in limbic brain areas.

Brain derived neurotropic factor in first-episode psychosis

There is much interest, derived from current neurochemical, genetic, and therapeutic research, in the role of brain neurotrophins in schizophrenia. Neurotrophins play key roles in neuronal development and differentiation (i.e., promoting dendritogenesis and synaptogenesis), and in orchestrating the neuronal response to stress/noxious stimuli. Additionally, neurotrophins are modulators across monominergic (dopamine and serotonin), gabaergic and cholinergic systems. These roles focus on important areas of the etiopathophysiology of schizophrenia. Clinical studies show reductions in brain-derived neurotrophic factor (BDNF) and nerve growth factor (NFG) in schizophrenic patients as compared to normal control subjects, as well as differences in patients receiving first-generation antipsychotics (FGAs) or second-generation antipsychotics (SGAs). We now report on BDNF levels in subjects with first-episode psychosis in comparison with normal healthy controls. Compared to normal controls (N=14; 290.5+/-38.81 pg/ml), first-episode psychotic patients showed significant reduction (N=15; 135+/-21.77 pg/ml; P=0.001; f=12.873) in plasma BDNF. Additionally, plasma BDNF levels showed a significant negative correlation (N=13' r=0.584, P=0.0362) only with positive symptom scores at base line and no significant correlations were found with any of the cognitive performance test battery or motor function test scores. Low BDNF levels at the onset of psychosis suggest that it may contribute to the pathogenesis of schizophrenia and/or perhaps could be a helpful neurobiological marker for possible early treatment intervention.

Cholinergic circuits and signaling in the pathophysiology of schizophrenia

Central cholinergic signaling has long been associated with aspects of memory, motivation, and mood, each affected functions in neuropsychiatric disorders such as schizophrenia. In this chapter, we review evidence related to the core hypothesis that dysregulation of central cholinergic signaling contributes to the pathophysiology of schizophrenia. Although central cholinergic circuits are resistant to simplification-particularly when one tries to parse the contributions of various classes of cholinergic receptors to disease related phenomena--the potential role of ACh signaling in Schizophrenia pathophysiology deserves careful consideration for prospective therapeutics. The established role of cholinergic circuits in attentional tuning is considered along with recent work on how the patterning of cholinergic activity may modulate corticostriatal circuits affected in schizophrenia.

Schizophrenia-associated neural growth factors in peripheral blood. A review

In this paper we review the findings on neural growth factors in the peripheral blood of schizophrenia patients. The studies we review provide evidence for the fact that in schizophrenia the levels of growth factors in peripheral blood are disturbed. The most robust results (7 studies) are reported for S100B protein, which seems to be elevated in acute psychosis and in patients with predominant negative symptoms. We conclude that there are aberrant levels of growth factors in peripheral blood in schizophrenia patients, probably most notably in patients with negative symptoms. Large-scale longitudinal multivariate studies, investigating the levels of several growth factors at the same time might give insight in etiological processes and identify clinically useful subsets of patients within the heterogeneous schizophrenia sample.

Differential effects of haloperidol and olanzapine on the expression of erythropoietin and its receptor in rat hippocampus and striatum

Compared with first-generation antipsychotics (FGAs), second-generation antipsychotics (SGAs) seem to be neuroprotective and trigger neuroplasticity. Because neuroplasticity is regulated by a variety of neurotrophic factors we studied differential effects of haloperidol (HAL, a FGA) and olanzapine (OLZ, a SGA) on temporal expression of erythropoietin (EPO), a potent neuroprotective factor and its receptor (EPOr) in rat brain. Rats (8-10/group) were treated with HAL or OLZ for 14 days (HAL-14 or OLZ-14) or 45 days (HAL-45 or OLZ-45). Animals were killed by decapitation or by perfusion to collect brains for immunoblotting and immunohistochemical analysis respectively. In hippocampus, the levels of both EPO and EPOr were significantly increased in HAL-14 (p < 0.001) and OLZ-14 (p < 0.001) groups. Their levels decreased in HAL-45 compared with levels in HAL-14 (EPO, p < 0.001; EPOr, p < 0.05), whereas the levels were further increased (EPO, p < 0.05) in OLZ-45 compared with OLZ-14. In striatum, the levels of both EPO and EPOr were unchanged in HAL-14 and EPO levels significantly decreased in HAL-45 (p < 0.05), whereas their levels were significantly increased in OLZ-14 and OLZ-45 compared with the vehicle-treated control (p < 0.001). Both EPO and EPOr were primarily expressed by neurons and endothelial cells. These data suggest that SGAs such as OLZ may have neuroprotective effects through expression of EPO that may be clinically relevant for long-term safe and beneficial management of psychotic patients.

Haloperidol and atypical antipsychotics share a same action of decreasing P75NTR mRNA levels in PC12 cells

P75(NTR) is a common neurotrophin receptor which binds all neurotrophins with similar affinities and has been shown to be capable of mediating programmed cell death. In this study, we investigated effects of the antipsychotic drugs (APDs) haloperidol, clozapine, quetiapine, and risperidone on p75(NTR) mRNA levels in PC12 cells. Haloperidol is a prototype of typical APDs, and the other three drugs are atypical APDs, which are effective in reducing negative symptoms and cognitive deficits of schizophrenia, cause less side effects, and are more tolerable compared to haloperidol. PC12 cells were cultured with various concentrations of haloperidol, clozapine, quetiapine, or risperidone, in their media. After culture for 48h, the cell viabilities and p75(NTR) mRNA levels were measured. It was shown that both haloperidol and the atypical APDs used in this study deceased p75(NTR) mRNA levels in PC12 cells in a dose dependent manner, while not affecting cell viabilities. In further experiments, doses that produced significant/greatest effects were chosen and provided in the culture media for various periods. Decreases in p75(NTR) mRNA levels were observed in cultures treated for 12h with quetiapine, 24h with clozapine or risperidone, or for 48h with haloperidol. These results suggest that both haloperidol and atypical APDs have the same action of decreasing p75(NTR) mRNA levels in PC12 cells. Although the underlying molecular mechanism of this action remains to be elucidated, this finding is particularly relevant given the neurodevelopmental deficits associated with schizophrenia and important roles of p75(NTR) in mediating cell death.

Lithium increases nerve growth factor levels in the rat hippocampus in an animal model of mania

Pharmacological studies suggest that neurotrophins may play a role in the effects of lithium and valproate on mood regulation. In this study, we tested the hypotheses that lithium and valproate would reverse and prevent the behavioral and biochemical effects of amphetamine, using a rat model of mania. In the reversal treatment, male Wistar rats were first administered D-amphetamine or saline for 14 days, and then, between days 8-14, rats were treated with lithium, valproate or saline. In the prevention treatment, rats were pretreated with lithium, valproate or saline, and then, between days 8-14, rats were administered D-amphetamine or saline. Locomotor behavior was assessed using the open-field task and hippocampal nerve growth factor levels were determined by enzyme-linked immunosorbent assay. Both lithium and valproate reversed and prevented D-amphetamine-induced hyperactivity. Lithium increased nerve growth factor content in rat hippocampus in both experiments, but this effect was blocked with the co-administration of D-amphetamine. No significant effects on nerve growth factor levels were observed with valproate or D-amphetamine alone. These findings suggest that nerve growth factor may play a role in the neurotrophic effects of lithium but do not support the hypotheses that the nerve growth factor/TrkA pathway is involved in the pathophysiology of bipolar disorder.

Adequate antipsychotic treatment normalizes serum nerve growth factor concentrations in schizophrenia with and without cannabis or additional substance abuse

Neurotrophins such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are important for the development and maintenance of neuron function. Neurodevelopment is thought to be impaired in schizophrenia, and vulnerable schizophrenic brains may be more sensitive to toxic influences. Thus, cannabis as a neurotoxin (and other substances) may be more harmful to schizophrenic brains than to non-schizophrenic brains, when used chronically. In a previous study we demonstrated an earlier disease onset and significantly higher serum NGF concentrations in drug-naïve schizophrenic patients with previous long-term cannabis abuse than in schizophrenics without cannabis abuse or cannabis abusers without schizophrenia. We therefore investigated whether this difference is still observed after treatment. Serum NGF measured in 114 treated schizophrenic patients (schizophrenia alone, n=66; schizophrenia plus cannabis abuse, n=42; schizophrenia plus multiple substance abuse, n=6) no longer differed significantly among those groups and from the control groups (healthy controls, n=51; cannabis controls, n=24; multiple substance controls, n=6). These results were confirmed by an additional prospective study in 28 patients suffering from schizophrenia (S) or schizophrenia with cannabis abuse (SC). Previously elevated serum NGF levels in the drug-naïve state, also differing between the groups (S: 83.44+/-265.25 pg/ml; SC: 246.89+/-310.24 pg/ml, S versus SC: p=0.03) dropped to 10.72+/-14.13 pg/ml (S) and 34.19+/-38.96 pg/ml (SC) (S versus SC, p>0.05), respectively, after adequate antipsychotic treatment. We thus conclude that antipsychotic treatment leads to recovery of neural integrity, as indicated by renormalized NGF values.