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

Central insulin dysregulation in antipsychotic-naïve first-episode psychosis: In silico exploration of gene expression signatures

Antipsychotic drug (AP)-naïve first-episode psychosis (FEP) patients display premorbid cognitive dysfunctions and dysglycemia. Brain insulin resistance may link metabolic and cognitive disorders in humans. This suggests that central insulin dysregulation represents a component of the pathophysiology of psychosis spectrum disorders (PSDs). Nonetheless, the links between central insulin dysregulation, dysglycemia, and cognitive deficits in PSDs are poorly understood. We investigated whether AP-naïve FEP patients share overlapping brain gene expression signatures with central insulin perturbation (CIP) in rodent models. We systematically compiled and meta-analyzed peripheral transcriptomic datasets of AP-naïve FEP patients along with hypothalamic and hippocampal datasets of CIP rodent models to identify common transcriptomic signatures. The common signatures were used for pathway analysis and to identify potential drug treatments with discordant (reverse) signatures. AP-naïve FEP and CIP (hypothalamus and hippocampus) shared 111 and 346 common signatures respectively, which were associated with pathways related to inflammation, endoplasmic reticulum stress, and neuroplasticity. Twenty-two potential drug treatments were identified, including antidiabetic agents. The pathobiology of PSDs may include central insulin dysregulation, which contribute to dysglycemia and cognitive dysfunction independently of AP treatment. The identified treatments may be tested in early psychosis patients to determine if dysglycemia and cognitive deficits can be mitigated.

Vascular-related biomarkers in psychosis: a systematic review and meta-analysis

Background

While the molecular underpinnings of vascular dysfunction in psychosis are under active investigation, their implications remain unclear due to inconsistent and sometimes sparse observations. We conducted a comprehensive meta-analysis to critically assess the alterations of vascular-related molecules in the cerebrospinal fluid (CSF) and blood of patients with psychotic disorders compared with healthy individuals.

Methods

Databases were searched from inception to February 23, 2023. Meta-analyses were performed using a random-effects model. Meta-regression and subgroup analyses were conducted to assess the effects of clinical correlates.

Results

We identified 93 eligible studies with 30 biomarkers investigated in the CSF and/or blood. Among the biomarkers examined, psychotic disorders were associated with elevated CSF-to-serum albumin ratio (standardized mean difference [SMD], 0.69; 95% confidence interval [CI], 0.35-1.02); blood S100B (SMD, 0.88; 95% CI, 0.59-1.17), matrix metalloproteinase-9 (MMP-9; SMD, 0.66; 95% CI, 0.46-0.86), and zonulin (SMD, 1.17; 95% CI, 0.04-2.30). The blood levels of S100B, MMP-9, nerve growth factor (NGF), vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), and vascular adhesion molecule 1 (VCAM-1) were altered in patient subgroups differing in demographic and clinical characteristics. Blood S100B level was positively correlated with age and duration of illness. Substantial between-study heterogeneity was observed in most molecules.

Conclusion

The alterations in certain vascular-related fluid markers in psychotic disorders suggest disturbances in normal vascular structures and functions. However, not all molecules examined displayed clear evidence of changes. While potential impacts of clinical factors, including the administered treatment, were identified, the exploration remained limited. Further studies are needed to investigate the diverse patterns of expression, and understand how these abnormalities reflect the pathophysiology of psychosis and the impact of clinical factors.

Biomarkers in the cerebrospinal fluid of patients with psychotic disorders compared to healthy controls: a systematic review and meta-analysis

Psychotic disorders are severe mental disorders with poorly understood etiology. Biomarkers in the cerebrospinal fluid (CSF) could provide etiological clues and diagnostic tools for psychosis; however, an unbiased overview of CSF alterations in individuals with psychotic disorders is lacking. The objective of this study was to summarize all quantifiable findings in CSF from individuals with psychotic disorders compared to healthy controls (HC). Studies published before January 25th, 2023 were identified searching PubMed, EMBASE, Cochrane Library, Web of Science, ClinicalTrials.gov, and PsycINFO. Screening, full-text review, data extraction, and risk of bias assessments were performed by two independent reviewers following PRISMA guidelines. Findings in patients and healthy controls were compared and summarized using random-effects analyses and assessment of publication bias, subgroup and sensitivity analyses were performed. 145 studies, covering 197 biomarkers, were included, of which 163 biomarkers have not previously been investigated in meta-analyses. All studies showed some degree of bias. 55 biomarkers measured in CSF were associated with psychosis and of these were 15 biomarkers measured in ≥2 studies. Patients showed increased levels of noradrenaline (standardized mean difference/SMD, 0.53; 95% confidence interval/CI, 0.16 to 0.90) and its metabolite 3-methoxy-4-hydroxyphenylglycol (SMD, 0.30; 95% CI: 0.05 to 0.55), the serotonin metabolite 5-hydroxyindoleacetic acid (SMD, 0.11; 95% CI: 0.01 to 0.21), the pro-inflammatory neurotransmitter kynurenic acid (SMD, 1.58; 95% CI: 0.34 to 2.81), its precursor kynurenine (SMD,0.99; 95% CI: 0.60 to 1.38), the cytokines interleukin-6 (SMD, 0.58; 95% CI: 0.39 to 0.77) and interleukin-8 (SMD, 0.43; 95% CI: 0.24 to 0.62), the endocannabinoid anandamide (SMD, 0.78; 95% CI: 0.53 to 1.02), albumin ratio (SMD, 0.40; 95% CI: 0.08 to 0.72), total protein (SMD, 0.29; 95% CI: 0.16 to 0.43), immunoglobulin ratio (SMD, 0.45; 95% CI: 0.06 to 0.85) and glucose (SMD, 0.48; 95% CI: 0.01 to 0.94). Neurotensin (SMD, -0.67; 95% CI: -0.89 to -0.46) and γ-aminobutyric acid (SMD, -0.29; 95% CI: -0.50 to -0.09) were decreased. Most biomarkers showed no significant differences, including the dopamine metabolites homovanillic acid and 3,4-dihydroxyphenylacetic acid. These findings suggest that dysregulation of the immune and adrenergic system as well as blood-brain barrier dysfunction are implicated in the pathophysiology of psychotic disorders.

Predictive effect of Bayes discrimination in the level of serum protein factors and cognitive dysfunction in schizophrenia

Finding molecular biomarkers that can be related to the degree of cognitive dysfunction in schizophrenia remains a challenge. The levels of 6 Serum Protein Factors (NGF, BDNF, IL-6, TNF-α, S100β, GFAP) in peripheral blood of patients with schizophrenia were measured. The cognitive function of patients with schizophrenia was assessed by MATRICS Consensus Cognitive Battery (MCCB), a systematic assessment tool of international gold standard for cognitive function assessment of schizophrenia. To explore the correlation between these 6 biomarkers and the degree of cognitive dysfunction in schizophrenia,78 schizophrenic patients and 71 healthy controls were included in the study. The serum concentrations of BDNF and GFAP were lower in the patient group, but the concentrations of IL-6, TNF-α and S100β were higher. The speed of information processing, word learning, reasoning and problem solving, visual learning T-score of the patient group were lower than the control group. Bayes discriminant function model has a high correct discriminant rate for the severity of cognitive dysfunction in schizophrenia. The level of serum protein factor and clinical symptom score of schizophrenia may forecast the degree of cognitive dysfunction, which is expected to be a potential biomarker to identify the degree of cognitive dysfunction of schizophrenia, and provide objective basis for the clinical diagnosis and treatment of patients with schizophrenia.

Nerve Growth Factor, Stress and Diseases

Stress is a constant threat for homeostasis and is represented by different extrinsic and intrinsic stimuli (stressors, Hans Selye's "noxious agents"), such as aggressive behavior, fear, diseases, physical activity, drugs, surgical injury, and environmental and physiological changes. Our organisms respond to stress by activating the adaptive stress system to activate compensatory responses for restoring homeostasis. Nerve Growth Factor (NGF) was discovered as a signaling molecule involved in survival, protection, differentiation, and proliferation of sympathetic and peripheral sensory neurons. NGF mediates stress with an important role in translating environmental stimuli into physiological and pathological feedbacks since NGF levels undergo important variations after exposure to stressful events. Psychological stress, lifestyle stress, and oxidative stress are well known to increase the risk of mental disorders such as schizophrenia, major depressive disorders, bipolar disorder, alcohol use disorders and metabolic disorders such as metabolic syndrome. This review reports recent works describing the activity of NGF in mental and metabolic disorders related to stress.

Vitamin D and Neurotrophin Levels and Their Impact on the Symptoms of Schizophrenia

INTRODUCTION

Vitamin D is involved in brain development and functioning, as well as in regulation of neurotrophic factors. Changes in the expression of those factors are possibly responsible for morphologic abnormalities and symptoms in patients suffering from schizophrenia.

OBJECTIVE

The main goal of this research was to investigate the interrelationship between vitamin D, nerve growth factors (NGF, brain-derived neurotrophic factor [BDNF], and neuregulin-1 [NRG1]), and schizophrenia symptom domains.

METHODS

This research included 97 inpatients diagnosed with schizophrenia. Schizophrenia symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). Blood samples were taken in order to analyze concentrations of vitamin D, BDNF, NRG1, and NGF growth factors. The obtained results were used in a multiple regression analysis.

RESULTS

The vitamin D concentration positively affected the concentration of NRG1 (F = 8.583, p = 0.005) but not the concentration of other investigated growth factors (BDNF and NGF). The clinical characteristics and symptom domains of schizophrenia seemed to be unaffected by the concentrations of vitamin D, BDNF, and NGF, while the NRG1 concentration significantly affected positive symptom domains of schizophrenia (F = 4.927, p = 0.030).

CONCLUSION

The vitamin D concentration positively affected NRG1 levels but not schizophrenia symptomatology as measured by PANSS. The as-sociation between the two could be intermediated via NRG1.

Different serum protein factor levels in first-episode drug-naive patients with schizophrenia characterized by positive and negative symptoms

AIM

The clinical features of schizophrenia can be mainly divided into two symptom domains: positive and negative. Patients in each symptom domain respond differently to treatments, and their prognoses vary accordingly. Serum protein factors, such as nerve growth factor (NGF), neurotrophin-3 (NT-3), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and the calcium-binding protein, S100β, have been reported to be involved in the pathogenesis of schizophrenia. However, their roles in the positive and negative symptom domains have not been determined. In this study, we investigated whether the serum levels of these five protein factors differed among first-episode drug-naive schizophrenia patients in each symptom domain and in healthy controls.

METHODS

Double-antibody sandwich ELISA were used to quantify the amounts of the five protein factors in serum.

RESULTS

Compared with the levels in the controls (n = 60), increased serum levels of IL-6, IL-1β, and S100β and decreased serum levels of NGF and NT-3 were observed in first-episode drug-naive schizophrenia patients. Additionally, the serum levels of IL-6 and IL-1β were significantly higher in schizophrenia patients characterized by negative symptoms (negative group, n = 37) than in those characterized by positive symptoms (positive group, n = 46). Based on multivariate regression analyses, serum levels of IL-1β were positively associated with the Negative Symptom subscore of the Positive and Negative Syndrome Scale in the negative group and in all patients with schizophrenia.

CONCLUSION

The two subtypes of schizophrenia may have different pathological mechanisms. Patients characterized by negative symptoms probably have more serious disturbances in neuroimmunology.

Cerebrospinal fluid neuroplasticity-associated protein levels in patients with psychiatric disorders: a multiplex immunoassay study

To examine the role of neuroplasticity in the pathology of psychiatric disorders, we measured cerebrospinal fluid (CSF) neuroplasticity-associated protein levels. Participants were 94 patients with schizophrenia, 68 with bipolar disorder (BD), 104 with major depressive disorder (MDD), and 118 healthy controls, matched for age, sex, and ethnicity (Japanese). A multiplex immunoassay (22-plex assay) was performed to measure CSF neuroplasticity-associated protein levels. Among 22 proteins, 11 were successfully measured in the assay. CSF amyloid precursor protein (APP) and glial cell-derived neurotrophic factor (GDNF) levels were significantly lower in patients with schizophrenia, and CSF APP and neural cell adhesion molecule (NCAM)-1 levels were significantly lower in patients with BD, than in healthy controls (all p < 0.05). Positive and Negative Syndrome Scale total, positive, and general scores were significantly and positively correlated with CSF hepatocyte growth factor (HGF) (p < 0.01) and S100 calcium-binding protein B (S100B) (p < 0.05) levels in patients with schizophrenia. Young mania-rating scale score was significantly and positively correlated with CSF S100B level in patients with BD (p < 0.05). Hamilton Depression Rating Scale, core, sleep, activity, somatic anxiety, and delusion subscale scores were significantly and positively correlated with CSF HGF level, while sleep subscale score was positively correlated with CSF S100B and VEGF receptor 2 levels in patients with MDD (p < 0.05). Our results suggest that CSF APP, GDNF, and NCAM-1 levels are associated with psychiatric disorders, and that CSF HGF, S100B, and VEGF receptor 2 levels are related to psychiatric symptoms.

The Role of Biomarkers in Psychiatry

Psychiatric illnesses are cognitive and behavioral disorders of the brain. At present, psychiatric diagnosis is based on DSM-5 criteria. Even if endophenotype specificity for psychiatric disorders is discussed, it is difficult to study and identify psychiatric biomarkers to support diagnosis, prognosis, or clinical response to treatment. This chapter investigates the innovative biomarkers of psychiatric diseases for diagnosis and personalized treatment, in particular post-genomic data and proteomic analyses.

Chronic cannabis use and circulating biomarkers of neural health, stress, and inflammation in physically active individuals

Previous research has associated cannabis use with altered circulating neurotrophins and biomarkers of immune health, but these relationships have yet to be fully explored in physically active individuals. The specific aim of this study was to explore the relationships between biomarkers of neural health: nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), immune health: interleukin 6 (IL-6), C-reactive protein (CRP), and cortisol, as well as the presence of depression, in physically active cannabis users (CU) and nonusers (NU). Male and female participants (N = 30; CU, n = 15, NU, n = 15) provided intravenous blood samples and underwent assessment of body composition, maximal oxygen consumption, and depression (Beck Depression Inventory-II (BDI-II)). Samples were analyzed for concentrations of NGF, BDNF, IL-6, CRP, and cortisol using ELISAs. CU and NU were compared using an unpaired t test. Pearson's correlation and multiple linear regression were used to evaluate relationships among variables. There were no significant differences in body size or composition, maximal oxygen consumption, total BDI-II Score, concentrations of NGF, IL-6, CRP, or cortisol between groups. BDNF was significantly lower in CU compared with NU (p = 0.02), with a significant negative relationship between BDNF and CRP (p = 0.02). Mean concentrations of CRP placed CU at higher risk for cardiovascular disease compared with NU. Total BDI-II score negatively correlated with BDNF (p = 0.02) and positively correlated with CRP (p = 0.02). Novelty Plasma BDNF was significantly lower in physically active cannabis users compared with NU. CU were classified at moderate risk for cardiovascular disease based on average circulating CRP compared with low risk for NU.

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.

Rs7219 Regulates the Expression of GRB2 by Affecting miR-1288-Mediated Inhibition and Contributes to the Risk of Schizophrenia in the Chinese Han Population

In the present study, we examined a potential genetic association between the variant rs7219 within the 3'-UTR of GRB2 and the susceptibility to schizophrenia (SCZ) and bipolar disorder (BD) in the Chinese Han population. A genetic association study, including 548 SCZ patients, 512 BD patients, and 598 normal controls, was conducted in the Chinese Han population. Genotyping was performed through the Sequenom MassARRAY technology platform. The expression of GRB2 was detected using quantitative real-time polymerase chain reaction (qRT-PCR). A dual-luciferase reporter assay was performed to determine whether miR-1288 could bind to the 3'-UTR region of GRB2 containing rs7219. We found that rs7219 was significantly associated with the susceptibility to SCZ under different genetic models, including additive [OR (95% CI) = 1.24 (1.02-1.49), P = 0.027], dominant [OR (95% CI) = 1.31 (1.04-1.66), P = 0.025], and allelic models[OR (95% CI) = 1.24 (1.03-1.49), P = 0.027]. However, no significant associations were found between rs7219 and the risk for BD (all P > 0.05). Moreover, we observed that the expression of GRB2 significantly decreased in SCZ patients compared with the controls (P = 0.004). The dual-luciferase reporter assay showed that the minor allele C of rs7219 significantly decreased the luciferase activity by binding miR-1288 (P < 0.001). In summary, we are the first to reveal that rs7219 is significantly associated with the susceptibility to SCZ in the Chinese Han population. Moreover, the minor allele C of rs7219 is identified as a risk allele for SCZ because it generates a binding site for miR-1288, thereby resulting in decreased expression of GRB2 and ultimately increasing the risk of SCZ.

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.

Brain, blood, cerebrospinal fluid, and serum biomarkers in schizophrenia

Over the last decade, finding a reliable biomarker for the early detection of schizophrenia (Scz) has been a topic of interest. The main goal of the current review is to provide a comprehensive view of the brain, blood, cerebrospinal fluid (CSF), and serum biomarkers of Scz disease. Imaging studies have demonstrated that the volumes of the corpus callosum, thalamus, hippocampal formation, subiculum, parahippocampal gyrus, superior temporal gyrus, prefrontal and orbitofrontal cortices, and amygdala-hippocampal complex were reduced in patients diagnosed with Scz. It has been revealed that the levels of interleukin 1β (IL-1β), IL-6, IL-8, and TNF-α were increased in patients with Scz. Decreased mRNA levels of brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), neurotrophin-3 (NT-3), nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) genes have also been reported in Scz patients. Genes with known strong relationships with this disease include BDNF, catechol-O-methyltransferase (COMT), regulator of G-protein signaling 4 (RGS4), dystrobrevin-binding protein 1 (DTNBP1), neuregulin 1 (NRG1), Reelin (RELN), Selenium-binding protein 1 (SELENBP1), glutamic acid decarboxylase 67 (GAD 67), and disrupted in schizophrenia 1 (DISC1). The levels of dopamine, tyrosine hydroxylase (TH), serotonin or 5-hydroxytryptamine (5-HT) receptor 1A and B (5-HTR1A and 5-HTR1B), and 5-HT1B were significantly increased in Scz patients, while the levels of gamma-aminobutyric acid (GABA), 5-HT transporter (5-HTT), and 5-HT receptor 2A (5-HTR2A) were decreased. The increased levels of SELENBP1 and Glycogen synthase kinase 3 subunit α (GSK3α) genes in contrast with reduced levels of B-cell translocation gene 1 (BTG1), human leukocyte antigen DRB1 (HLA-DRB1), heterogeneous nuclear ribonucleoprotein A3 (HNRPA3), and serine/arginine-rich splicing factor 1 (SFRS1) genes have also been reported. This review covers various dysregulation of neurotransmitters and also highlights the strengths and weaknesses of studies attempting to identify candidate biomarkers.

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.

Cerebrospinal fluid biomarker candidates of schizophrenia: where do we stand?

Here, we review the cerebrospinal fluid (CSF) candidate markers with regard to their clinical relevance as potential surrogates for disease activity, prognosis assessment, and predictors of treatment response. We searched different online databases such as MEDLINE and EMBASE for studies on schizophrenia and CSF. Initial studies on cerebrospinal fluid in patients with schizophrenia revealed increased brain-blood barrier permeability with elevated total protein content, increased CSF-to-serum ratio for albumin, and intrathecal production of immunoglobulins in subgroups of patients. Analyses of metabolites in CSF suggest alterations within glutamatergic neurotransmission as well as monoamine and cannabinoid metabolism. Decreased levels of brain-derived neurotrophic factor and nerve growth factor in CSF of first-episode patients with schizophrenia reported in recent studies point to a dysregulation of neuroprotective and neurodevelopmental processes. Still, these findings must be considered as non-specific. A more profound characterization of the particular psychopathological profiles, the investigation of patients in the prodromal phase or within the first episode of schizophrenia promoting longitudinal investigations, implementation of different approaches of proteomics, and rigorous adherence to standard procedures based on international CSF guidelines are necessary to improve the quality of CSF studies in schizophrenia, paving the way for identification of syndrome-specific biomarker candidates.

Reduced maternal and cord nerve growth factor levels in preterm deliveries

Nerve growth factor (NGF) is a neurotrophin, which exerts an important role in the development and function of the central and peripheral nervous system. There is limited information regarding the levels of NGF during pregnancy and its role in fetal development. We have earlier reported increased oxidative stress in pregnancy complications. The present study examines the levels of NGF in maternal and cord samples in preterm deliveries and its association with oxidative stress marker. A total number of 96 women delivering preterm (<37 weeks gestation) and 94 women delivering at term (control group) (≥37 weeks gestation) were recruited. Plasma NGF levels were measured in both mother and cord plasma using the Emax Immuno Assay System Promega kit. Maternal and cord plasma NGF levels were significantly reduced (p<0.05 for both) in women delivering preterm as compared to term. There was a positive association between maternal and cord plasma NGF levels (p=0.022). Maternal NGF levels were negatively (p=0.017) associated with maternal malondialdehyde (MDA) levels. Reduced cord NGF levels may affect fetal growth in preterm deliveries which may have implications for the neurodevelopmental pathologies in later life. Circulating maternal NGF levels in preterm pregnancies may be a useful marker to predict NGF levels in the neonate.

Autism and cancer risk

A literature review was conducted on the genetic and developmental bases of autism in relation to genes and pathways associated with cancer risk. Convergent lines of evidence from four types of analysis: (1) recent theoretical studies on the causes of autism, (2) epidemiological studies, (3) genetic analyses linking autism with mutations in tumor suppressor genes and other cancer-associated genes and pathways, and (4) contrasts with schizophrenia, Parkinson's, and Alzheimer's disease indicate that autism may involve altered cancer risk. This evidence should motivate further epidemiological studies, and it provides useful insights into the nature of the genetic, epigenetic, and environmental factors underlying the etiologies of autism, other neurological conditions, and carcinogenesis.

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.

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.

Nerve growth factor, birth outcome and pre-eclampsia

The present study compares nerve growth factor (NGF) levels between preeclamptic (PE) (n=86) and normotensive (NT) women (n=105) and their associations with blood pressure and infant size. Maternal plasma NGF levels were reduced (p<0.05) in the PE group as compared to the NT group. Furthermore, NGF levels were reduced in PE mothers delivering low birth weight babies (LBW) as compared to NT mothers delivering LBW babies. Maternal NGF levels were negatively (p=0.029) associated with blood pressure in preeclamptic mothers. Cord NGF levels were negatively associated (p=0.026) with birth weight in the normotensive group. NGF levels are differently regulated in preeclamptic and normotensive mothers delivering LBW babies. Future studies need to investigate mechanisms underlying this pathophysiology and follow-up of these babies to better understand the role of NGF in brain development in later life.

Decreased BDNF levels in CSF of drug-naive first-episode psychotic subjects: correlation with plasma BDNF and psychopathology

Brain-derived neurotrophic factor (BDNF), which plays an important role in neurodevelopmental plasticity and cognitive performance, has been implicated in neuropsychopathology of schizophrenia. We examined the levels of both cerebrospinal fluid (CSF) and plasma BDNF concomitantly in drug-naive first-episode psychotic (FEP) subjects with ELISA to determine if these levels were different from control values and if any correlation exists between CSF and plasma BDNF levels. A significant reduction in BDNF protein levels was observed in both plasma and CSF of FEP subjects compared to controls. BDNF levels showed significant negative correlation with the scores of baseline PANSS positive symptom subscales. In addition, there was a significant positive correlation between plasma and CSF BDNF levels in FEP subjects. The parallel changes in BDNF levels in plasma and CSF indicate that plasma BDNF levels reflect the brain changes in BDNF levels in schizophrenia.