Serum levels of brain-derived neurotrophic factor in patients with schizophrenia and bipolar disorder

Correlations between omega-3 fatty acids and inflammatory/glial abnormalities: the involvement of the membrane and neurotransmitter dysfunction in schizophrenia

Introduction

Macrophages or T-lymphocytes triggered inflammation and, consequently, activated glial cells may contribute to neuroinflammation and neurotransmitter dysfunction in schizophrenia (SZ), while omega(n)-3 polyunsaturated fatty acids (PUFAs) can attenuate some SZ symptoms through anti-inflammatory effects. However, the correlations between macrophage/T-lymphocyte-produced cytokines and glia phenotypes, between inflammatory status and PUFAs composition, between cytokines and neurotransmitter function, and between n-3 PUFAs and neurotransmitter abnormality in SZ are unclear.

Methods

Changes in T-helper (h) patterns, peripheral macrophage/glial markers, PUFAs profile, membrane fluidity, and neurotransmitter functions were evaluated in SZ patients (n = 50) and healthy controls (n = 30) using ELISA, gas chromatography, fluorescence anisotropy techniques, and HPLC, respectively.

Results

Compared to the control, blood lymphocyte proliferation, the concentration of macrophage/microglia phenotype M1 markers, including cytokines IL-1β, TNF-α (Th1) and IL-6 (Th2), and astrocyte phenotype A1 marker S100β was significantly increased, while IL-17 and n-3 PUFAs contents, n-3/n-6 ratio, and membrane fluidity (FLU) were significantly decreased in SZ. Moreover, increased DA and HVA, decreased 5-HT and NE, and their metabolites appeared in SZ. Moreover, negative correlations between IL-6 and A2 marker Brain-Derived Neurotrophic Factor (BDNF) or n-3 PUFAs EPA and between IL-1β and FLU or 5HIAA, while positive correlations between EPA and 5-HIAA and between FLU and DHA were found in SZ.

Discussion

These findings showed (1) no clear Th pattern, but pro-inflammatory-dominant immunity occurred; (2) the pro-inflammatory pattern may result in the activated microglia M1 and astrocyte A1 phenotype; and (3) increased pro-inflammatory cytokines were related to decreased n-3 PUFA and decreased membrane fluidity and dysfunctional neurotransmitter systems in SZ.

The role of integrin beta in schizophrenia: a preliminary exploration

Integrins are transmembrane heterodimeric (αβ) receptors that transduce mechanical signals between the extracellular milieu and the cell in a bidirectional manner. Extensive research has shown that the integrin beta (β) family is widely expressed in the brain and that they control various aspects of brain development and function. Schizophrenia is a relatively common neurological disorder of unknown etiology and has been found to be closely related to neurodevelopment and neurochemicals in neuropathological studies of schizophrenia. Here, we review literature from recent years that shows that schizophrenia involves multiple signaling pathways related to neuronal migration, axon guidance, cell adhesion, and actin cytoskeleton dynamics, and that dysregulation of these processes affects the normal function of neurons and synapses. In fact, alterations in integrin β structure, expression and signaling for neural circuits, cortex, and synapses are likely to be associated with schizophrenia. We explored several aspects of the possible association between integrin β and schizophrenia in an attempt to demonstrate the role of integrin β in schizophrenia, which may help to provide new insights into the study of the pathogenesis and treatment of schizophrenia.

The Influence of Electroconvulsive Therapy (ECT) on Brain-Derived Neurotrophic Factor (BDNF) Plasma Level in Patients with Schizophrenia-A Systematic Review and Meta-Analysis

The main aim of this systematic review and meta-analysis is to establish whether there is a correlation between the brain-derived neurotrophic factor (BDNF) level and electroconvulsive therapy (ECT) treatment and the reduction in psychotic symptoms in patients diagnosed with schizophrenia. A systematic search of PubMed/Medline, Cochrane Library, Web of Science, Scopus and Embase was conducted up to March 2023. Inclusion criteria: studies in which adult patients with schizophrenia treated with antipsychotic medication received ECT therapy and had the BDNF level measured before and after ECT treatment. Exclusion criteria: animal and in vitro studies or studies not involving complete information about the treatment and concentration of BDNF in plasma. The risk of bias was assessed using Egger's regression-based test for meta-analysis with continuous outcomes. Six studies comprising 248 individuals with schizophrenia were included. A statistically significant increase in BDNF levels after ECT treatment was observed only in two studies (p < 0.001 and p < 0.027, respectively), whereas in four other studies, an upward trend without statistical significance was noticed. The estimated overall size effect revealed that ECT therapy caused a slight change in the BDNF level but without statistical significance (ES = -0.328). Different numbers of ECT procedures (4-10), final measurement of the BDNF level made at a different time point, using bilateral or unilateral electrode positioning during ECT and treatment with different combinations of typical or atypical antipsychotic medications may be potential reasons for the lack of statistical significance in the changes in BDNF levels after treatment. Data regarding the measurement of BDNF levels pre and post ECT therapy in patients with schizophrenia are very limited without an extended follow-up period and evaluation of mental health change. Our meta-analysis showed that treatment with ECT therapy and antipsychotic medication increases serum BDNF levels in patients with drug-resistant schizophrenia compared to patients treated with medication only; however, this effect is not statistically significant.

Brain-derived Neurotrophic Factor and High Sensitive C-reactive Protein in Bipolar Depression and Unipolar Depression: The Practical Usage as a Discriminatory Tool

Objective

Brain-derived neurotrophic factor (BDNF) and high sensitive C-reactive protein (hs-CRP) have been reported to play roles in depression and bipolar disorder (BD). However, the probable discriminatory properties of these biologic markers are less investigated. We aimed to assess the serum BDNF and hs-CRP levels among Iranian patients with major depressive disorder (MDD) and BD during a depressive episode and investigate the optimum cut-off point for differential diagnosis of BD and MDD.

Methods

We recruited 30 patients with MDD, 30 with BD in depressive mood and 30 healthy comparators. Blood sample was taken from each participant to measure BDNF and hs-CRP levels. We also used receiver operating characteristic (ROC) curve analysis to find an optimal cut-off point for differentiating MDD from BD according to pre-defined variables.

Results

The mean age of total study population was 37.3 ± 5.0 years (males: 49%). BDNF was significantly lower in patients with BD, followed by MDD subjects and healthy controls 541.0 ± 601.0 pg/ml vs. 809.5 ± 433.3 pg/ml vs. 1,482.1 ± 519.8, respectively, p < 0.001). The area under curve of ROC curve analysis for BD versus MDD was 0.704 (95% confidence interval: 0.564-0.844, p = 0.007). We also found that the BDNF cut-off value of 504 could appropriately distinguished BD from MDD (sensitivity: 73%, specificity: 70%). No significant association were identified in terms of hs-CRP levels.

Conclusion

Patients suffering from BD had lowest BDNF levels compared to MDD or healthy adults and this biomarker could play a practical role differentiating MDD from BD. Several studies are required confirming our outcomes.

Neurohemodynamic correlates of BDNF gene expression in schizophrenia patients with working memory deficits: A functional MRI study

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) is involved in neuroplasticity underlying cognitive deficits, including working memory deficits (WMD), in schizophrenia. Methodological challenges and inconsistencies are reported with peripheral BDNF levels. Left dorsolateral prefrontal cortex (DLPFC) is proposed to underlie WMD, though inconsistently. We aimed to explore the correlations between brain activation during working memory task-based functional Magnetic Resonance Imaging (fMRI) and BDNF gene expression in schizophrenia patients with WMD.

METHODS

26 patients with schizophrenia with established WMD were recruited for the study. Blood samples were collected to study lymphocyte BDNF gene expression. Patients underwent task-based fMRI to examine the working memory performance and related brain activation. Whole-brain analysis was performed with 2-back > 0-back and 2-back > rest contrast. The peak intensity values of the activation were used for correlation analysis.

RESULTS

Whole brain analysis with 2-back > rest contrast revealed maximum activation in left DLPFC, Brodmann area 9 (t = 10.54, FWE corrected p < 0.05). The baseline BDNF gene expression correlated positively with the peak intensity of brain activation in left DLPFC (r = 0.365, p = 0.033). Negative symptom score negatively correlated with BDNF gene expression (r = -0.499, p = 0.005) and left DLPFC fMRI activation (r = -0.393, p = 0.023) respectively.

CONCLUSION

We found a significant positive association between BDNF gene expression and the activation of the DLPFC during the working memory task. This novel observation needs further systematic evaluation to establish the potential role of peripheral BDNF expression in WMD in schizophrenia.

Exploring the association between brain-derived neurotrophic factor levels and longitudinal psychopathological and cognitive changes in Sardinian psychotic patients

Background and hypothesis

Schizophrenia spectrum disorders are among the most debilitating mental disorders and has complex pathophysiological underpinnings. There is growing evidence that brain-derived neurotrophic factor (BDNF) can play a role in its pathogenesis. The present study investigated the longitudinal variation of serum BDNF levels in a 24-month observational prospective cohort study of Sardinian psychotic patients and its relationship with psychopathological and cognitive changes. Furthermore, we examined whether genetic variation within the BDNF gene could moderate these relationships.

Study design

Every 6 months, 105 patients were assessed for their BDNF serum levels, as well as for a series of psychopathological, cognitive, and social measures. We performed a targeted analysis of four tag single nucleotide polymorphisms within the BDNF gene that were selected and analyzed using polymerase chain reaction. Longitudinal data were analyzed using mixed-effects linear regression models.

Study results

We observed a declining longitudinal trajectory of BDNF levels in psychotic patients in general, and in relation to the severity of depressive and negative symptoms. BDNF serum levels also declined in patients scoring lower in cognitive measures such as attention and speed of information processing and verbal fluency. The rs7934165 polymorphism moderated the significant association between verbal fluency and BDNF levels.

Conclusions

These findings in patients from real-world settings suggest a plausible role of peripheral BDNF levels as a marker of illness burden in schizophrenia spectrum disorders.

BDNF, GDNF, NGF and Klotho levels and neurocognitive functions in acute term of schizophrenia

BACKGROUND

Klotho and its relationship with neurotrophic factors and cognition in schizophrenia has not yet been investigated. In this study, the hypothesis that the blood serum levels of BDNF, GDNF, NGF and Klotho in schizophrenia patients and healthy controls would be related to cognitive functions was investigated.

METHODS

In this study, two groups were assessed: schizophrenia patients (case group) who were hospitalised in the Psychiatry Clinic of Sakarya University Training and Research Hospital and healthy volunteers (control group). The patients were evaluated on the 1st and 20th days of their hospitalisation with the Positive and Negative Syndrome Scale (PANSS), the Brief Psychiatric Rating Scale (BPRS), the General Assessment of Functioning Scale (GAF) and the Clinical Global Impression Scale (CGI). For cognitive assessment, both groups were evaluated with the Wechsler Memory Scale-Visual Production Subtest (Wechsler Memory Scale III-Visual Reproduction Subtest) and the Stroop test.

RESULTS

BDNF, GDNF, NGF and Klotho levels were lower in schizophrenia patients than in healthy controls. In the schizophrenia patients, on the 20th day of treatment, there was a statistically significant increase in BDNF compared to the 1st day of treatment. BDNF, GDNF and Klotho showed positive correlations with some cognitive functions in the healthy controls. BDNF, GDNF, NGF and Klotho levels were intercorrelated and predictive of each other in both groups.

CONCLUSION

This study suggests a relationship between cognitive functions, neurotrophic factors and Klotho. Most of the results are the first of their kind in the extant literature, while other results are either similar to or divergent from those generated in previous studies. Therefore, new, enhanced studies are needed to clarify the role of Klotho and neurotrophic factors in schizophrenia.

Diabetes mellitus, cognitive deficits and serum BDNF levels in chronic patients with schizophrenia: A case-control study

The relationship between serum BDNF levels and cognitive dysfunction in schizophrenia (SCZ) patients comorbid with type 2 diabetes mellitus (T2DM) has not been reported. Hence, this study aimed to explore whether and how the changes of serum BDNF levels were correlated with cognitive impairment in SCZ patients comorbid with T2DM. We recruited 472 inpatients with chronic SCZ (54 T2DM and 418 non-T2DM), and 225 healthy controls. Serum BDNF levels and routine biochemical parameters were measured. Psychopathological symptoms were evaluated by the Positive and Negative Syndrome Scale (PANSS) and cognitive function was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). SCZ patients with T2DM had significantly higher serum BDNF levels than SCZ patients without T2DM (F = 11.31, p = 0.001). SCZ patients with T2DM scored higher in delayed memory than SCZ patients without T2DM (77.17 ± 18.44 vs.66.24 ± 19.51, p = 0.000), and still showed significance after controlling for confounders. Further stepwise multiple regression analysis identified serum BDNF as an independent contributor to the RBANS attention of SCZ patients with T2DM (β = 0.30, t = 2.09, p = 0.042). The increase of BDNF levels and better cognitive performance, especially delayed memory, may be related to the pathophysiological process of T2DM in chronic SCZ patients.

Brain-derived neurotrophic factor (BDNF) levels in first-episode schizophrenia and healthy controls: A comparative study

BACKGROUND

Abnormalities in brain development and plasticity have been associated with the pathophysiology of schizophrenia. The role of brain-derived neurotrophic factor (BDNF) in schizophrenia is the recent area of interest because it regulates neurogenesis. The current study aimed to assess and compare serum BDNF levels between first-episode schizophrenia patients and healthy controls, and evaluate its correlation with the socio-demographic and clinical variables.

METHODOLOGY

It was a cross-sectional comparative study for the assessment of serum BDNF levels between patients with first-episode schizophrenia (N=50) and healthy controls (N-50) conducted in the Department of Psychiatry at a tertiary care public hospital attached to a medical school in North India. Participants were assessed for the socio-demographic parameters, nicotine dependence, and clinical details using structured scales. Serum BDNF level estimated using the sandwich ELISA technique. The comparison between the groups was done by using a Student t-test or chi-square test. Spearman correlation was performed between mean BDNF scores and demographic or illness variables in both first-episode schizophrenia and healthy control groups.

RESULTS

There was a significantly lower mean score of total serum BDNF levels in first-episode schizophrenia patients as compared to controls (8.44 ± 1.54 vs 10.44 ± 2.04; t = 5.52, p < 0.001; 95% CI = 1.28-2.71). The total FTND scores for smokeless tobacco use were negatively correlated to BDNF levels among healthy controls (r=-0.30, p=0.03) as well as in the first-episode schizophrenia group (r=-0.32, p= 0.04). None of the other illness-related variables were correlated to serum BDNF values in the first episode schizophrenia group.

CONCLUSION

Individuals with first-episode schizophrenia have lower serum BDNF levels than healthy controls. The illness-related factors such as duration of untreated psychosis or psychopathology were not correlated with BDNF levels. Thus abnormal signaling of BDNF can lead to abnormal brain functioning which can make an individual more susceptible to schizophrenia.

Brain-derived neurotrophic factor levels and psychopathology scores in drug-naïve first-episode psychosis

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) is involved in the regulation of many neuronal processes, including neurogenesis. Therefore, it is thought to be closely associated with many psychopathologies with a neurodevelopmental basis, for example, schizophrenia.

METHODS

The patients admitted to the Psychiatry Department of the Faculty of Medicine with a diagnosis of non-affective drug-naïve first-episode psychosis (FEP) were included in the study. The relationship between laboratory and clinical findings and psychometric data (Positive and Negative Syndrome Scale) was examined.

RESULTS

The study population consisted of 34 FEP and 34 healthy control (HC) volunteers. Mean BNDF levels of FEP and HC groups were 14.95 ± 6.13 and 17.89 ± 4.84 pg/ml, respectively. The difference between the groups was statistically significant (t = 2.197; p = .032). There was a negative correlation between mean BDNF levels and PANSS general psychopathology subscale scores (r = .358; p = .038), and total PANSS scores (r = .356; p = .039).

DISCUSSION

There is a consensus on low serum BDNF levels both in FEP and in schizophrenia. However, it is still not clear which clinical findings are associated with lower serum BDNF levels. The relationship between BDNF levels and psychopathologies in schizophrenia has to be investigated.

Childhood trauma, psychiatric disorders, and criminality in women: Associations with serum levels of brain-derived neurotrophic factor

Psychiatric disorders and childhood trauma are highly prevalent in female inmates. Brain-derived neurotrophic factor (BDNF) plays a number of roles in neuronal survival, structure, and function. Data in the literature suggest that it is a neurobiological substrate that moderates the impact of childhood adversities on the late expression of psychiatric disorders. The aim of this study was to determine whether five childhood trauma subtypes-physical abuse, sexual abuse, emotional abuse, physical neglect, and emotional neglect-are associated with adult psychiatric disorders, BDNF levels, and criminality among incarcerated women. This was a cross-sectional study involving a consecutive sample of 110 women, divided into three groups of women (forensic - mentally ill who committed crimes, clinical psychiatric inpatients and healthy controls). The Childhood Trauma Questionnaire and the Mini-International Neuropsychiatric Interview-Plus were applied in the whole sample, and BDNF levels were measured in a sub-sample of 54 women. The rates of mental illness and childhood trauma were high in the forensic group. Emotional abuse was higher in the clinical and forensic groups than in the healthy control group. Lower BDNF levels were associated with emotional abuse in the forensic group as well as with sexual abuse in the healthy control group. After multinomial logistic regression, lower levels of BDNF, higher levels of emotional abuse and the presence of familial offense were considered factors related to clinical psychiatric group. The results of this study underscore the idea that BDNF may be an important factor related to the development of diseases and criminality in women who are victims of childhood trauma, becoming a possible biological marker.

Hippocampal and prefrontal cortical NMDA receptors mediate the interactive effects of olanzapine and lithium in memory retention in rats: the involvement of CAMKII-CREB signaling pathways

RATIONALE

Treatment of bipolar disorder (BPD) with lithium and olanzapine concurrent administration is a major medicine issue with the elusive neurobiological mechanisms underlying the cognitive function.

OBJECTIVE

To clarify the precise mechanisms involved, the possible role of the hippocampus (HPC) and prefrontal cortical (PFC) NMDA receptors and CAMKII-CREB signaling pathway in the interactive effects of lithium and olanzapine in memory consolidation was evaluated. The dorsal hippocampal CA1 regions of adult male Wistar rats were bilaterally cannulated and a step-through inhibitory avoidance apparatus was used to assess memory consolidation. The changes in p-CAMKII/CAMKII and p-CREB/CREB ratio in the HPC and the PFC were measured by Western blot analysis.

RESULTS

Post-training administration of lithium (20, 30, and 40 mg/kg, i.p.) dose-dependently decreased memory consolidation whereas post-training administration olanzapine (2 and 5 mg/kg, i.p.) increased memory consolidation. Post-training administration of certain doses of olanzapine (1, 2, and 5 mg/kg, i.p.) dose-dependently improved lithium-induced memory impairment. Post-training administration of ineffective doses of the NMDA (10-5 and 10-4 μg/rat, intra-CA1) plus an ineffective dose of olanzapine (1 mg/kg, i.p.) dose-dependently improved the lithium-induced memory impairment. Post-training microinjection of ineffective doses of the NMDA (10-5 and 10-4 μg/rat, intra-CA1) dose-dependently potentiated the memory improvement induced by olanzapine (1 mg/kg, i.p.) on lithium-induced memory impairment which was associated with the enhancement of the levels of p-CAMKII and p-CREB in the HPC and the PFC. Post-training microinjection of ineffective doses of the noncompetitive NMDA receptor antagonist, MK-801 (0.0625 and 0.0125 μg/rat, intra-CA1), dose-dependently decreased the memory improvement induced by olanzapine (5 mg/kg, i.p.) on lithium-induced memory impairment which was related to the reduced levels of HPC and PFC CAMKII-CREB.

CONCLUSION

The results strongly revealed that there is a functional interaction among lithium and olanzapine through the HPC and the PFC NMDA receptor mechanism in memory consolidation which is mediated with the CAMKII-CREB signaling pathway.

Peripheral blood BDNF-TrkB signaling in first-episode, drug-free patients with major depressive disorder and schizophrenia

Brain-derived neurotrophic factor (BDNF) has been implicated in the pathogenesis of psychiatric disorders, and studies have shown BDNF aberrations in major psychiatric diseases including schizophrenia (SCZ) and major depressive disorder (MDD). However, data from clinical studies were inconsistent. In this study, we recruited 34 patients with MDD, 77 patients with SCZ and 65 healthy control (HC) subjects to clarify the circulating BDNF levels in MDD and SCZ patients, and to assess whether serum BDNF levels were associated with the disease severity. Our results showed that serum BDNF levels were significantly decreased in the patients with SCZ (Mean difference = -4.517, 95%CI of difference = -7.854 to -1.180, p < 0.01) and MDD (Mean difference = -5.699, 95%CI of difference = -9.892 to -1.506, p < 0.01) when compared with HC subjects. Sub-group analyses suggested that BDNF levels were significantly reduced in the female SCZ (Mean difference = -5.700, 95%CI of difference = -10.21 to -1.189, p < 0.01) and MDD (Mean difference = -5.840, 95%CI of difference = -10.66 to -1.019, p < 0.05) patients, but not in male patients. Further analyses indicated that serum BDNF levels were not correlated with disease severity of MDD and SCZ. In addition, the transcriptional expression of TrkB was significantly down-regulated in the blood of MDD patients, but not in SCZ patients. However, there was no significant correlation between BDNF concentrations and TrkB mRNA levels. Taken together, our results revealed differential changes of BDNF-TrkB signaling in MDD and SCZ patients, therefore contributed to a better understanding of MDD and SCZ pathophysiology.

Adjunctive memantine for major mental disorders: A systematic review and meta-analysis of randomized double-blind controlled trials

OBJECTIVE

As a non-competitive N-methyl-d-aspartate receptor antagonist, memantine has been used to treat major mental disorders including schizophrenia, bipolar disorder, and major depressive disorder (MDD). This meta-analysis systematically investigated the effectiveness and tolerability of adjunctive memantine for patients with schizophrenia, bipolar disorder, and MDD.

METHODS

Only randomized controlled trials (RCTs) were identified and included in the study. Data of the three disorders were separately synthesized using the RevMan 5.3 software.

RESULTS

Fifteen RCTs (n = 988) examining memantine (5-20 mg/day) as an adjunct treatment for schizophrenia (9 trials with 512 patients), bipolar disorder (3 trials with 319 patients), and MDD (3 trials with 157 patients) were analyzed. Memantine outperformed the comparator regarding total psychopathology with a standardized mean difference (SMD) of -0.56 [95% confidence interval (CI): -1.01, -0.11; I² = 76%, P = 0.01] and negative symptoms with an SMD of -0.71 (95% CI: -1.09, -0.33; I² = 74%, P = 0.0003) in schizophrenia, but no significant effects were found with regard to positive symptoms and general psychopathology in schizophrenia, or depressive and manic symptoms in bipolar disorder or depressive symptoms in MDD. Memantine outperformed the comparator in improving cognitive performance in schizophrenia with an SMD of 1.07 (95% CI: 0.53, 1.61; P < 0.0001, I² = 29%). No group differences were found in the rates of adverse drug reactions and discontinuation due to any reason in the three major mental disorders.

CONCLUSIONS

Memantine as an adjunct treatment appears to have significant efficacy in improving negative symptoms in schizophrenia. The efficacy and safety of adjunctive memantine for bipolar disorder or MDD needs to be further examined.

REVIEW REGISTRATION

PROSPERO: 42018099045.

Whole blood transcriptomic profiles can differentiate vulnerability to chronic low back pain

The mechanisms underlying the transition from acute to chronic pain remain unclear. Here, we sought to characterize the transcriptome associated with chronic low back pain as well as the transcriptome of the transition from acute to chronic low back pain. For the analysis, we compared the whole blood transcriptome of: (a) patients at the onset of low back pain who no longer had pain within 6 weeks after onset (acute) with patients who developed chronic low back pain at 6 months (chronic T5); and, (b) patients at the onset of low back pain (chronic T1) who developed chronic pain at 6 months with healthy pain-free (normal) controls. The majority of differentially expressed genes were protein coding. We illustrate a unique chronic low back pain transcriptome characterized by significant enrichment for known pain genes, extracellular matrix genes, and genes from the extended major histocompatibility complex (MHC) genomic locus. The transcriptome of the transition from acute to chronic low back pain was characterized by significant upregulation of antigen presentation pathway (MHC class I and II) genes and downregulation of mitochondrial genes associated with oxidative phosphorylation, suggesting a unique genomic signature of vulnerability to low back pain chronicity.

Brain-derived neurotrophic factor is associated with cognitive impairments in first-episode and chronic schizophrenia

Brain-derived neurotrophic factor (BDNF) may be related to the pathophysiology of schizophrenia. This study aims to examine the relation between plasma BDNF levels and the cognition of patients with schizophrenia. We recruited 31 patients with chronic schizophrenia, 34 first-episode patients, and 35 healthy control subjects. We examined the MATRICS Consensus Cognitive Battery (MCCB) and the plasma BDNF levels in all groups. The schizophrenic symptoms were assessed using the positive and negative syndrome scale. The BDNF levels of schizophrenic patients were remarkably lower than those of the controls. The cognitive MCCB global composite scores and part index scores of schizophrenic patients were remarkably lower than those of the controls. Moreover, remarkable correlations were observed between BDNF levels and partial cognitive dimensions, such as visual learning, memory, and processing speed. Therefore, BDNF may be involved in the pathophysiology and cognitive impairment of schizophrenia.

Oligopeptidases activity in bipolar disorder: Ndel1 and angiotensin I converting enzyme

BACKGROUND

Abnormal activity of two enzymes relevant to neurodevelopment, namely nuclear-distribution element-like 1 (Ndel1) and angiotensin I-converting enzyme (ACE), was reported in individuals with schizophrenia; to our knowledge, these oligopeptidases were never measured in bipolar disorder (BD).

AIMS

Evaluate the enzyme activity of Ndel1 and ACE in euthymic individuals with BD type 1 which was compare to healthy control (HC) group.

METHODS

Ndel1 and ACE activities were assessed in the serum of individuals with BD type 1 according to DSM-IV criteria (n = 70) and a HC group (n = 34). The possible differences between BD type 1 and HC groups were evaluated using Analysis of Covariance (ANCOVA), and the results were adjusted for age, gender and body mass index.

RESULTS

We observed a positive correlation between Ndel1 activity and the total YMRS score in BD group (p = 0.030) and a positive correlation between ACE activity and Ham-D score (p = 0.047). ANCOVA analysis showed lower Ndel1 activity in BDs compared to HCs. Interestingly, we did not observe between-groups differences in ACE activity, despite the recognized correlation of ACE activity levels with cognitive functions, also described to be worsened in psychiatric patients.

CONCLUSION

Oligopeptidases, especially Ndel1, which has been strongly correlated with neurodevelopment and brain formation, are potentially a good new target in the study of the neurobiology of BD.

LIMITATIONS

The relatively small sample size did not permit to examine the cause-effect relationship of clinical dimensions of BD and the enzymatic activity.

Elevated brain-derived neurotrophic factor (BDNF) serum levels in an acute episode of schizophrenia in polish women: Correlation with clinical and metabolic parameters

Brain-derived neurotrophic factor (BDNF) has been implicated in the pathogenesis of psychiatric disorders. Schizophrenia is associated with metabolic abnormalities and BDNF regulates energy homeostasis and glucose metabolism in peripheral tissues. The aim of this study was to examine serum levels of BDNF in schizophrenic women during 8 weeks of treatment and control group, and its correlation with clinical and metabolic parameters. The study was performed on a group of 96 women: 55 diagnosed with paranoid schizophrenia according to DSM-IV criteria, and 41 healthy controls. Positive and Negative Syndrome Scale (PANSS) was used to assess the severity of schizophrenia. BDNF serum levels and metabolic parameters: fasting serum glucose, total cholesterol, triglyceride (TG), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C) were measured at baseline and week 8 of treatment. BDNF serum levels were significantly elevated in medicated patients with schizophrenia comparing to controls. After 8 weeks of antipsychotic treatment, BDNF levels did not significantly change. Increase in TG and TG/HDL-C ratio and a decrease in HDL-C was detected in medicated patients. Correlation between BDNF and lipid profile as well as symptoms severity was found. In our study we detected abnormalities in BDNF levels and lipid profile in medicated schizophrenic women in Polish population.

Contribution of Endocannabinoid Gene Expression and Genotype on Low Back Pain Susceptibility and Chronicity

BACKGROUND

A major research emphasis has been focused on defining the molecular changes that occur from acute to chronic pain to identify potential therapeutic targets for chronic pain. As the endocannabinoid system is dynamically involved in pain signaling, a plausible mechanism that may contribute to chronic pain vulnerability involves alterations in the amount of circulating endocannabinoids. Therefore, this study sought to examine cannabinoid type 1 (CNR1), type 2 (CNR2) receptors, fatty acid amide hydrolase (FAAH), and the vanilloid receptor (transient receptor potential cation channel subfamily V member 1 [TRPV1]) gene expression profiles among individuals with acute and chronic low back pain (cLBP) at their baseline visit. We also assessed associations among selected single nucleotide polymorphisms (SNPs) of FAAH and CNR2 and measures of somatosensory function and self-report pain measures.Using a previously established quantitative sensory testing protocol, we comprehensively assessed somatosensory parameters among 42 acute LBP, 42 cLBP, and 20 pain-free participants. Samples of whole blood were drawn to examine mRNA expression and isolate genomic DNA for genotyping.CNR2 mRNA was significantly upregulated in all LBP patients compared with controls. However, FAAH mRNA and TRPV1 mRNA were significantly upregulated in cLBP compared with controls. A significant association was observed between FAAH SNP genotype and self-report pain measures, mechanical and cold pain sensitivity among LBP participants. cLBP participants showed increased FAAH and TRPV1 mRNA expression compared with acute LBP patients and controls.Further research to characterize pain-associated somatosensory changes in the context of altered mRNA expression levels and SNP associations may provide insight on the molecular underpinnings of maladaptive chronic pain.

Pathologic role of nitrergic neurotransmission in mood disorders

Mood disorders are chronic, recurrent mental diseases that affect millions of individuals worldwide. Although over the past 40 years the biogenic amine models have provided meaningful links with the clinical phenomena of, and the pharmacological treatments currently employed in, mood disorders, there is still a need to examine the contribution of other systems to the neurobiology and treatment of mood disorders. This article reviews the current literature describing the potential role of nitric oxide (NO) signaling in the pathophysiology and thereby the treatment of mood disorders. The hypothesis has arisen from several observations including (i) altered NO levels in patients with mood disorders; (ii) antidepressant effects of NO signaling blockers in both clinical and pre-clinical studies; (iii) interaction between conventional antidepressants/mood stabilizers and NO signaling modulators in several biochemical and behavioral studies; (iv) biochemical and physiological evidence of interaction between monoaminergic (serotonin, noradrenaline, and dopamine) system and NO signaling; (v) interaction between neurotrophic factors and NO signaling in mood regulation and neuroprotection; and finally (vi) a crucial role for NO signaling in the inflammatory processes involved in pathophysiology of mood disorders. These accumulating lines of evidence have provided a new insight into novel approaches for the treatment of mood disorders.

The complex association between the antioxidant defense system and clinical status in early psychosis

Oxidative stress is a pathophysiological mechanism potentially involved in psychiatric disorders. The objective of this study was to assess the relationship between total antioxidant status (TAS) and the functional status of patients with a first episode of psychosis at the onset of the disease. For this purpose, a sample of 70 patients aged between 9 and 17 years with a first episode of psychosis were followed up for a period of two years. Blood samples were drawn to measure TAS levels at three time points: at baseline, at one year, and at two years. Clinical symptoms and functioning were also assessed at the same time points using various scales. Linear regression analysis was performed to investigate the relationship between TAS and clinical status at each assessment, adjusting for potential confounding factors. The distribution of clinical variables was grouped in different percentiles to assess the dose-response in the relation between clinical variables and TAS. At baseline, patient's score on Children's Global Assessment Scale (CGAS) was directly and significantly associated with TAS with a monotonic increase in percentiles, and surprising this association was reversed after one and two years of follow-up with a monotonic decrease. In summary at the onset of the illness, TAS is positively related to clinical status, whereas as the illness progresses this correlation is reversed and becomes negative. This may be the result of an adaptive response.

Association between serum levels of glutamate and neurotrophic factors and response to clozapine treatment

Clozapine is the only available therapy for about 30% of schizophrenia patients otherwise refractory to antipsychotics. Unfortunately, the mechanism of action of the drug is still unknown and there are no biomarkers that can predict a positive response to clozapine. We aimed to examine serum neurotrophins and glutamate levels as putative biomarkers for clozapine response based on the hypothesized mode-of-action of the compound. Blood samples of 89 chronic schizophrenia patients maintained on clozapine were analyzed in a cross-sectional design. Serum brain derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), neurotrophic growth factor (NGF), glial derived neurotrophic factor (GDNF) and glutamate were determined. Differences between responders and non-responders to clozapine and correlation between clinical and biological measures were analyzed. Our sample consisted of 54 (61%) responders and 35 (39%) non-responders. Responders had higher mean BDNF levels than non-responders (2066±814 vs. 1668±820pg/ml, p<0.05. respectively) and higher serum glutamate levels (1.61±2.2 vs. 0.66±0.9pg/ml, respectively, p<0.05). Furthermore, there was a significant correlation between serum glutamate levels and positive symptoms among the clozapine-responder group (rho=0.47, p<0.005). High serum levels of BDNF and glutamate were associated with response to clozapine, while glutamate levels correlated with the psychosis severity in clozapine responders only. Large-scale, prospective longitudinal studies are needed to support these findings and the assumption that serum glutamate and BDNF can discriminate between clozapine responders and non-responders.

Adjunctive memantine for schizophrenia: a meta-analysis of randomized, double-blind, placebo-controlled trials

BACKGROUND

Dysfunction of N-methyl-D-aspartate receptor (NMDAR) is involved in the pathophysiology of schizophrenia. A meta-analysis of randomized controlled trials (RCTs) was conducted to examine the efficacy and safety of memantine, a non-competitive NMDAR antagonist, in the treatment of schizophrenia.

METHODS

Standardized/weighted mean differences (SMDs/WMDs), risk ratio (RR), and their 95% confidence intervals (CIs) were calculated and analyzed.

RESULTS

Included in the meta-analysis were eight RCTs (n = 452) of 11.5 ± 2.6 weeks duration, with 229 patients on memantine (20 mg/day) and 223 patients on placebo. Adjunctive memantine outperformed placebo in the measures of Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale negative symptoms [SMD: -0.63 (95% CI -1.10 to -0.16), p = 0.009, I 2 = 77%], but not in the total, positive and general symptoms [SMD: -0.46 to -0.08 (95% CI -0.93 to 0.22), p = 0.06-0.60, I 2 = 0-74%] or the Clinical Global Impression Severity Scale [WMD: 0.04 (95% CI -0.24 to 0.32), p = 0.78]. The negative symptoms remained significant after excluding one outlying RCT [SMD: -0.41 (95% CI -0.72 to -0.11), p = 0.008, I 2 = 47%]. Compared with the placebo group, adjunctive memantine was associated with significant improvement in neurocognitive function using the Mini-Mental State Examination (MMSE) [WMD: 3.09, (95% CI 1.77-4.42), p < 0.00001, I 2 = 22%]. There was no significant difference in the discontinuation rate [RR: 1.34 (95% CI 0.76-2.37), p = 0.31, I 2 = 0%] and adverse drug reactions between the two groups.

CONCLUSIONS

This meta-analysis showed that adjunctive memantine appears to be an efficacious and safe treatment for improving negative symptoms and neurocognitive performance in schizophrenia. Higher quality RCTs with larger samples are warranted to confirm these findings.

Association of serum brain derived neurotropic factor with duration of drug-naive period and positive-negative symptom scores in drug naive schizophrenia

Introduction

The aim of this study was to compare the serum brain derived neurotropic factor (BNDF) levels of patients with schizophrenia who had never received an antipsychotic treatment with those of a control group. Also, to analyze the relationship between the Positive and Negative Symptom Scale (PANSS) scores and BDNF levels of the patients during the period they were drug-naive.

Materials and methods

The sample of the study comprised patients who presentedto the Psychiatry Clinic and were admitted after a distinctive schizophrenia diagnosis was made in accordance with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) diagnosis classification and who were not using and never had any antipsychotic medicine. A total of 160 participants were included in the study, 80 of whom had schizophrenia patients and 80 constituted the age- and sex-matched healthy control group. Before the start of the treatment, the serum samples to be checked for the BDNF levels were collected from the patients.

Results

The difference between the average BDNF levels of the groups were statistically significant (t = -5.25; p˂.001). An analysis as to whether there was a relation between the BDNF levels and the drug-naïve duration indicated no correlations. An examination of the relationship between PANSS scores and BDNF levels of the patients yielded no correlations.

Discussion

Serum BDNF levels seem to be one of the indicators of schizophrenia and its progress; nevertheless, we still do not have sufficient information about this neurotropic factor. In light of our study, the neurodevelopmental changes that occur at disease onset of the illness prominently affect the progress of the illness, which highlights the importance of the treatment in the early stages.

Acute Low Back Pain: Differential Somatosensory Function and Gene Expression Compared With Healthy No-Pain Controls

OBJECTIVES

Low back pain (LBP) is the second most frequently diagnosed pain condition in the United States, and although a majority of individuals have resolution of pain during the acute period, an estimated 40% of individuals will experience persistent pain. Given the heterogenous nature of LBP, this study sought to describe and compare somatosensory and molecular (gene expression) profiles between individuals with acute LBP and healthy no-pain controls.

METHODS

Using a previously established protocol, we comprehensively assessed somatosensory parameters among 31 no-pain control participants and 31 participants with acute LBP. Samples of whole blood were drawn to examine mRNA expression of candidate genes involved in the transduction, maintenance, and modulation of pain.

RESULTS

The acute LBP group exhibited increased pain sensitivity to cold stimuli, mechanical stimuli, including mechanical temporal summation at both the painful back area and remote location suggesting a mechanism of enhanced central nervous system excitability. In addition, deep tissue-specific peripheral sensitization was suggested due to significant differences in pressure pain threshold of the painful back area, but not the remote body site. Several genes that were differentially expressed were significantly associated with somatosensory alterations identified in the acute LBP group.

DISCUSSION

Acute LBP participants showed selective pain sensitivity enhancement and differential gene expression profiles compared with pain-free controls. Further research to characterize pain-associated somatosensory changes in the context of altered mRNA expression levels may provide insight on the molecular underpinnings of maladaptive chronic pain.

A comparison of the neutrophil-lymphocyte, platelet-lymphocyte and monocyte-lymphocyte ratios in schizophrenia and bipolar disorder patients - a retrospective file review

Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and monocyte-lymphocyte ratio (MLR) have recently been used as indicators of inflammation. Higher MLR and PLR values have been determined in the euthymic and manic periods in patients with bipolar disorder compared to a control group. High NLR values were determined in the only study investigating this ratio in schizophrenia patients. The purpose of this study was to compare NLR, PLR and MLR values and complete blood count elements in patients receiving treatment and hospitalized due to schizophrenic psychotic episode and bipolar disorder manic episode. All patients meeting the inclusion criteria among subjects receiving treatment and hospitalized due to schizophrenia-psychotic episode and bipolar affective disorder-manic episode at the Ondokuz Mayıs University Medical Faculty Psychiatry Department, Turkey, in 2012-2016 were included in our study. A total of 157 healthy donors were included as a control group. White blood cell (WBC), neutrophil, lymphocyte, platelet and monocyte numbers were noted retrospectively from complete blood counts at time of admission, and NLR, PLR and MLR were calculated from these. NLR, PLR and MLR values and platelet numbers in this study were higher and lymphocyte numbers were lower in bipolar disorder patients compared to the controls. Elevation in NLR, MLR and PLR values and neutrophil numbers and lower lymphocyte numbers were determined in schizophrenia patients compared to the controls. Higher NLR and MLR values were found in schizophrenia patients compared to bipolar disorder. Findings of our study supported the inflammation hypothesis for schizophrenia and bipolar disorder.

Val66Met functional polymorphism and serum protein level of brain-derived neurotrophic factor (BDNF) in acute episode of schizophrenia and depression

BACKGROUND

Brain-derived neurotrophic factor (BDNF) influences neuron differentiation during development as well as the synaptic plasticity and neuron survival in adulthood. BDNF has been implicated in the pathogenesis of schizophrenia and depression. Val66Met polymorphism and BDNF serum level are potential biomarkers in neuropsychiatric disorders. The aim of this study was to determine the effect of BDNF gene Val66Met functional polymorphism on serum BDNF concentration in patients with schizophrenia, during depression episode and in healthy control group.

METHODS

183 participants were recruited (61 patients with depressive episode, 56 females with schizophrenia, 66 healthy controls) from Polish population. Serum BDNF levels were measured using ELISA method. Val66Met polymorphism was genotyped using PCR- RFLP method.

RESULTS

Serum BDNF levels were not associated with Val66Met polymorphism in either of the groups. A significant increase of BDNF level in schizophrenia (p = 0.0005) and depression (p = 0.026) comparing to the control group has been observed.

CONCLUSIONS

Our results suggest that the functional Val66Met BDNF polymorphism is not associated with BDNF serum levels, which is in line with previous findings. Replication studies on larger groups are needed.

Brain-Derived Neurotrophic Factor Expression in Individuals With Schizophrenia and Healthy Aging: Testing the Accelerated Aging Hypothesis of Schizophrenia

PURPOSE OF REVIEW

Schizophrenia has been hypothesized to be a syndrome of accelerated aging. Brain plasticity is vulnerable to the normal aging process and affected in schizophrenia: brain-derived neurotrophic factor (BDNF) is an important neuroplasticity molecule. The present review explores the accelerated aging hypothesis of schizophrenia by comparing changes in BDNF expression in schizophrenia with aging-associated changes.

RECENT FINDINGS

Individuals with schizophrenia show patterns of increased overall mortality, metabolic abnormalities, and cognitive decline normally observed later in life in the healthy population. An overall decrease is observed in BDNF expression in schizophrenia compared to healthy controls and in older individuals compared to a younger cohort. There is a marked decrease in BDNF levels in the frontal regions and in the periphery among older individuals and those with schizophrenia; however, data for BDNF expression in the occipital, parietal, and temporal cortices and the hippocampus is inconclusive. Accelerated aging hypothesis is supported based on frontal regions and peripheral studies; however, further studies are needed in other brain regions.

Longitudinal assessment of brain-derived neurotrophic factor in Sardinian psychotic patients (LABSP): a protocol for a prospective observational study

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) plays a crucial role in neurodevelopment, synaptic plasticity and neuronal function and survival. Serum and plasma BDNF levels are moderately, but consistently, decreased in patients with schizophrenia (SCZ) compared with healthy controls. There is a lack of knowledge, however, on the temporal manifestation of this decline. Clinical, illness course and treatment factors might influence the variation of BDNF serum levels in patients with psychosis. In this context, we propose a longitudinal study of a cohort of SCZ and schizophrenic and schizoaffective disorder (SAD) Sardinian patients with the aim of disentangling the relationship between peripheral BDNF serum levels and changes of psychopathology, cognition and drug treatments.

METHODS AND ANALYSIS

Longitudinal assessment of BDNF in Sardinian psychotic patients (LABSP) is a 24-month observational prospective cohort study. Patients with SAD will be recruited at the Psychiatry Research Unit of the Department of Medical Science and Public Health, University of Cagliari and University of Cagliari Health Agency, Cagliari, Italy. We will collect BDNF serum levels as well as sociodemographic, psychopathological and neurocognitive measures. Structured, semistructured and self-rating assessment tools, such as the Positive and Negative Syndrome Scale for psychopathological measures and the Brief Assessment of Cognition in Schizophrenia for cognitive function, will be used.

ETHICS AND DISSEMINATION

This study protocol was approved by the University of Cagliari Health Agency Ethics Committee (NP2016/5491). The study will be conducted in accordance with the principles of good clinical practice, in the Declaration of Helsinki in compliance with the regulations. Participation will be voluntary and written informed consent will be obtained for each participant upon entry into the study. We plan to disseminate the results of our study through conference presentations and publication in international peer-reviewed journals. Access to raw data will be available in anonymised form upon request to the corresponding author.

The Efficacy of Non-Pharmacological Interventions on Brain-Derived Neurotrophic Factor in Schizophrenia: A Systematic Review and Meta-Analysis

Several studies have investigated the relationship between non-pharmacological interventions (NPIs) and peripheral brain-derived neurotrophic factor (BDNF) in schizophrenia patients. We conducted a systematic review and meta-analysis to review the efficacy of NPIs on peripheral serum and plasma BDNF in subjects with schizophrenia (including schizoaffective disorder). Meta-analyses were conducted to examine the effects of NPIs on blood BDNF levels by using the standardized mean differences (SMDs) between the intervention groups and controls. In total, six randomized controlled trials with 289 participants were included. Of them, five studies used exercise, physical training or diet products. One study used cognitive training. Overall, the BDNF levels in the NPI group increased significantly compared with the control groups (SMD = 0.95, 95% confidence interval (CI) = 0.07 to 1.83, p = 0.03). Subgroup analyses indicated beneficial effects of a non-exercise intervention on peripheral BDNF levels (SMD = 0.41, 95% CI = 0.08 to 0.74, p = 0.01). Meta-regression analyses showed that the completion rate influenced the variation in SMD (p = 0.01). Despite insufficient evidence to draw a conclusion, our results suggest that use of NPIs as adjunctive treatments, specifically non-exercise interventions, may affect positively serum or plasma BDNF in patients with schizophrenia.

Increased serum brain-derived neurotrophic factor levels following electroconvulsive therapy or antipsychotic treatment in patients with schizophrenia

BACKGROUND

Many schizophrenia patients experience residual symptoms even after treatment. Electroconvulsive therapy (ECT) is often used in medication-resistant schizophrenia patients when pharmacologic interventions have failed; however, the mechanism of action is unclear. Brain-derived neurotrophic factor (BDNF) levels are reduced in drug-naive, first-episode schizophrenia and are increased by antipsychotic treatment. We tested the hypothesis that ECT increases serum BDNF levels by measuring BDNF concentrations in schizophrenia patients before and after they received ECT.

METHODS

A total of 160 patients with schizophrenia were examined. The ECT group (n=80) was treated with antipsychotics and ECT (eight to 10 sessions administered every other day). The drug therapy group (n=80) received only antipsychotic treatment. A control group (n=77) was recruited that served as the baseline for comparison.

RESULTS

Baseline serum BDNF level in ECT group was lower than in controls (9.7±2.1 vs. 12.4±3.2ng/ml; P<0.001), but increased after ECT, such that there was no difference between the two groups (11.9±3.3 vs. 12.4±3.2ng/ml; P=0.362). There was no correlation between patients' Positive and Negative Syndrome Scale (PANSS) score and serum BDNF level before ECT; however, a negative correlation was observed after ECT (total: r=-0.692; P<0.01). From baseline to remission after ECT, serum BDNF level increased (P<0.001) and their PANSS score decreased (P<0.001). Changes in BDNF level (2.21±4.10ng/ml) and PANSS score (28.69±14.96) were positively correlated in the ECT group (r=0.630; P<0.01).

CONCLUSIONS

BDNF level was lower in schizophrenia patients relative to healthy controls before ECT and medication. BDNF level increased after ECT and medication, and its longitudinal change was associated with changes in patients' psychotic symptoms. These results indicate that BDNF mediates the antipsychotic effects of ECT.

DNA Methylation of BDNF Gene in Schizophrenia

Background

Although genetic factors are risk factors for schizophrenia, some environmental factors are thought to be required for the manifestation of disease. Epigenetic mechanisms regulate gene functions without causing a change in the nucleotide sequence of DNA. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that regulates synaptic transmission and plasticity. It has been suggested that BDNF may play a role in the pathophysiology of schizophrenia. It is established that methylation status of the BDNF gene is associated with fear learning, memory, and stressful social interactions. In this study, we aimed to investigate the DNA methylation status of BDNF gene in patients with schizophrenia.

Material/Methods

The study included 49 patients (33 male and 16 female) with schizophrenia and 65 unrelated healthy controls (46 male and 19 female). Determination of methylation pattern of CpG islands was based on the principle that bisulfite treatment of DNA results in conversion of unmethylated cytosine residues into uracil, whereas methylated cytosine residues remain unmodified. Methylation-specific PCR was performed with primers specific for either methylated or unmethylated DNA.

Results

There was no significant difference in methylated or un-methylated status for BDNF promoters between schizophrenia patients and controls. The mean duration of illness was significantly lower in the hemi-methylated group compared to the non-methylated group for BDNF gene CpG island-1 in schizophrenia patients.

Conclusions

Although there were no differences in BDNF gene methylation status between schizophrenia patients and healthy controls, there was an association between duration of illness and DNA methylation.

Molecular Pathways Bridging Frontotemporal Lobar Degeneration and Psychiatric Disorders

The overlap of symptoms between neurodegenerative and psychiatric diseases has been reported. Neuropsychiatric alterations are commonly observed in dementia, especially in the behavioral variant of frontotemporal dementia (bvFTD), which is the most common clinical FTD subtype. At the same time, psychiatric disorders, like schizophrenia (SCZ), can display symptoms of dementia, including features of frontal dysfunction with relative sparing of memory. In the present review, we discuss common molecular features in these pathologies with a special focus on FTD. Molecules like Brain Derived Neurotrophic Factor (BDNF) and progranulin are linked to the pathophysiology of both neurodegenerative and psychiatric diseases. In these brain-associated illnesses, the presence of disease-associated variants in BDNF and progranulin (GRN) genes cause a reduction of circulating proteins levels, through alterations in proteins expression or secretion. For these reasons, we believe that prevention and therapy of psychiatric and neurological disorders could be achieved enhancing both BDNF and progranulin levels thanks to drug discovery efforts.

Peripheral blood brain-derived neurotrophic factor in bipolar disorder: a comprehensive systematic review and meta-analysis

Peripheral blood brain-derived neurotrophic factor (BDNF) has been proposed as a potential biomarker related to disease activity and neuroprogression in bipolar disorder, speculated to mirror alterations in brain expression of BDNF. The research area is rapidly evolving; however, recent investigations have yielded conflicting results with substantial variation in outcomes, highlighting the need to critically assess the state of current evidence. The aims of the study were to investigate differences in peripheral blood BDNF concentrations between bipolar disorder patients and healthy control subjects and between affective states in bipolar disorder patients, including assessment of the effect of treatment of acute episodes on BDNF levels. A systematic review of English language studies without considering publication status was conducted in PubMed (January 1950-November 2014), Embase (1974-November 2014) and PsycINFO (1806-November 2014), and 35 studies comprising a total of 3798 participants were included in the meta-analysis. The results indicated that crude peripheral blood BDNF levels may be lower in bipolar disorder patients overall (Hedges' g=-0.28, 95% CI: -0.51 to -0.04, P=0.02) and in serum of manic (g=-0.77, 95% CI: -1.36 to -0.18, P=0.01) and depressed (g=-0.87, 95% CI: -1.42 to -0.32, P=0.002) bipolar disorder patients compared with healthy control subjects. No differences in peripheral BDNF levels were observed between affective states overall. Longer illness duration was associated with higher BDNF levels in bipolar disorder patients. Relatively low study quality, substantial unexplained between-study heterogeneity, potential bias in individual studies and indications of publication bias, was observed and studies were overall underpowered. It could thus not be excluded that identified differences between groups were due to factors not related to bipolar disorder. In conclusion, limitations in the evidence base prompt tempered conclusions regarding the role of peripheral BDNF as a biomarker in bipolar disorder and substantially improving the quality of further research is warranted.

The search for new biomarkers for cognition in schizophrenia

The search for biomarkers in cognition has been the focus of a large part of the research on patients suffering from schizophrenia. The scientific literature is heterogeneous, and few studies establishing an integrative model of pathogenesis and therapeutic response are available in this field. In this review, we aimed to summarize three essential aspects correlated with cognitive performance: 1) the relationship between inflammation and cognition in schizophrenia, 2) the role of prolactin in cognition, and 3) the association between cognition and neurotrophic factors, particularly brain-derived neurotrophic factor (BDNF). Several studies support the association of inflammatory markers with cognitive status in schizophrenia. In recent decades, the development of effective therapies for cognitive impairment in schizophrenia has focused on the search for anti-inflammatory and immunomodulatory medications. Conversely, the implications of prolactin and its functions in cognition, the transition to psychosis and the diagnosis and prognosis of schizophrenia have been established independent of antipsychotic treatment. With regard to neurotrophic factors, a recent study has correlated BDNF levels with cognitive recovery in schizophrenic patients treated with cognitive remediation. We conclude that although there is a diversity of biomarkers focused on cognitive function in schizophrenia, BDNF is the biomarker that has accumulated the vast majority of evidence in the current literature.

Serum brain-derived neurotrophic factor and cortical thickness are differently related in patients with schizophrenia and controls

Brain-derived neurotrophic factor (BDNF) has been implicated in neuronal plasticity, a key process related to the pathophysiology of schizophrenia. However, the relationship of peripheral levels of BDNF to cortical thickness and subcortical structures has not been extensively investigated. This study aims to investigate the relationship of peripheral serum BDNF levels to cortical thickness and volumes of the hippocampus and amygdala. Twenty-nine patients with schizophrenia and 32 healthy controls were included in this study. Structural magnetic resonance imaging (MRI) scans obtained in a 1.5 T scanner were performed in all subjects. Images were processed using Freesurfer software. Blood samples were collected on the same day of the MRI scan for BDNF peripheral levels. Vertex-wise analysis revealed significantly thinner cortex in patients compared with controls. BDNF levels and cortical thickness showed different patterns of correlation for patients and healthy controls in one cluster in the right hemisphere distributed across the supramarginal, postcentral, and inferior frontal cortices.

Peripheral brain-derived neurotrophic factor in schizophrenia and the role of antipsychotics: meta-analysis and implications

It has been postulated that schizophrenia (SZ) is related to a lower expression of brain-derived neurotrophic factor (BDNF). In the past few years, an increasing number of divergent clinical studies assessing BDNF in serum and plasma have been published. It is now possible to verify the relationship between BDNF levels and severity of symptoms in SZ as well as the effects of antipsychotic drugs on BDNF using meta-analysis. The aims of this study were to verify if peripheral BDNF is decreased in SZ, whether its levels are correlated with positive and negative symptomatology and if BDNF levels change after antipsychotic treatment. This report consists of two distinct meta-analyses of peripheral BDNF in SZ including a total of 41 studies and more than 7000 participants: (1) peripheral BDNF levels in serum and plasma were moderately reduced in SZ compared with controls. Notably, this decrease was accentuated with the disease duration. However, the extent of peripheral BDNF level decrease did not correlate with the severity of positive and negative symptoms. (2) In plasma, but not serum, peripheral BDNF levels are consistently increased after antipsychotic treatment irrespective of the patient's response to medication. In conclusion, there is compelling evidence that there are decreased levels of peripheral BDNF in SZ, in parallel to previously described reduced cerebral BDNF expression. It remains unclear whether these systemic changes are causally related to the development of SZ or if they are merely a pathologic epiphenomenon.

What's New in Traumatic Brain Injury: Update on Tracking, Monitoring and Treatment

Traumatic brain injury (TBI), defined as an alteration in brain functions caused by an external force, is responsible for high morbidity and mortality around the world. It is important to identify and treat TBI victims as early as possible. Tracking and monitoring TBI with neuroimaging technologies, including functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), positron emission tomography (PET), and high definition fiber tracking (HDFT) show increasing sensitivity and specificity. Classical electrophysiological monitoring, together with newly established brain-on-chip, cerebral microdialysis techniques, both benefit TBI. First generation molecular biomarkers, based on genomic and proteomic changes following TBI, have proven effective and economical. It is conceivable that TBI-specific biomarkers will be developed with the combination of systems biology and bioinformation strategies. Advances in treatment of TBI include stem cell-based and nanotechnology-based therapy, physical and pharmaceutical interventions and also new use in TBI for approved drugs which all present favorable promise in preventing and reversing TBI.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Altered BDNF is correlated to cognition impairment in schizophrenia patients with tardive dyskinesia

BACKGROUND

Long-term antipsychotic treatment for schizophrenia is often associated with the emergence of tardive dyskinesia (TD), which is linked to greater cognitive impairment. Brain-derived neurotrophic factor (BDNF) plays a critical role in cognitive function, and schizophrenia patients with TD have lower BDNF levels than those without TD.

OBJECTIVE

This study examines the BDNF levels, the cognitive function, and the association of BDNF with cognitive function in schizophrenia patients with or without TD.

METHODS

We recruited 83 male chronic patients with (n=35) and without TD (n=48) meeting DSM-IV criteria for schizophrenia and 52 male control subjects. We examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and BDNF levels for all subjects. Positive and Negative Symptom Scale (PANSS) and the Abnormal Involuntary Movement Scale (AIMS) were assessed in patients.

RESULTS

BDNF levels were lower in patients with than those without TD (p<0.05). RBANS total score (p<0.01) and subscales of immediate memory, visuospatial/constructional performance, and attention were lower in patients with than those without TD (all p<0.05). BDNF levels were positively associated with immediate memory in patients without TD, but negatively in TD patients (both p<0.05). Multiple regression analysis confirmed that in either TD or non-TD group, BDNF was an independent contributor to immediate memory (both p<0.05).

CONCLUSIONS

BDNF may be involved in the pathophysiology of TD. While the associations between BDNF and cognition in both TD and non-TD patients suggest a close relationship between BDNF and cognition, the different directions may implicate distinct mechanisms between TD and non-TD patients.

Brain-Derived Neurotrophic Factor and Delayed Verbal Recall in Crack/Cocaine Dependents

BACKGROUND/AIMS

Considering the role of brain-derived neurotrophic factor (BDNF) in memory processes and its peripheral response during the detoxification of cocaine, the aim of this study was to investigate whether plasma BDNF levels could be related to memory performance in women with crack/cocaine dependence.

METHODS

Twenty-five abstinent female crack/cocaine users (CCD) and 25 unmedicated healthy women (HW), carefully matched for age and years of formal education, were assessed regarding memory performance. Logical Memory was used to assess the immediate verbal recall (IVR), delayed verbal recall (DVR) and memory retention. Plasma BDNF levels were measured by Elisa immunoassay. Beck Depression Inventory was used to assess the severity of depressive symptoms, and the Cocaine Selective Severity Assessment the severity of cocaine abstinence symptoms.

RESULTS

The CCD group had lower DVR scores and higher plasma BDNF levels when compared to HW group. In addition, a linear regression model showed that BDNF levels predicted DVR scores within CCD group independently of depressive symptoms (R = 0.51; R(2) = 0.26; t(22) = 4.025, p = 0.03).

CONCLUSION

Despite higher plasma BDNF levels, crack users exhibited memory impairments when compared to healthy women. Specifically, peripheral BDNF levels predicted better cognitive performance only within individuals who already had cognitive impairment.

A Review of Biomarkers in Mood and Psychotic Disorders: A Dissection of Clinical vs. Preclinical Correlates

Despite significant research efforts aimed at understanding the neurobiological underpinnings of mood (depression, bipolar disorder) and psychotic disorders, the diagnosis and evaluation of treatment of these disorders are still based solely on relatively subjective assessment of symptoms as well as psychometric evaluations. Therefore, biological markers aimed at improving the current classification of psychotic and mood-related disorders, and that will enable patients to be stratified on a biological basis into more homogeneous clinically distinct subgroups, are urgently needed. The attainment of this goal can be facilitated by identifying biomarkers that accurately reflect pathophysiologic processes in these disorders. This review postulates that the field of psychotic and mood disorder research has advanced sufficiently to develop biochemical hypotheses of the etiopathology of the particular illness and to target the same for more effective disease modifying therapy. This implies that a "one-size fits all" paradigm in the treatment of psychotic and mood disorders is not a viable approach, but that a customized regime based on individual biological abnormalities would pave the way forward to more effective treatment. In reviewing the clinical and preclinical literature, this paper discusses the most highly regarded pathophysiologic processes in mood and psychotic disorders, thereby providing a scaffold for the selection of suitable biomarkers for future studies in this field, to develope biomarker panels, as well as to improve diagnosis and to customize treatment regimens for better therapeutic outcomes.

Decreased serum levels of brain-derived neurotrophic factor in schizophrenic patients with deficit syndrome

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a well-established neurotrophin that plays a role in the pathophysiology of numerous psychiatric disorders. Many studies have investigated the serum BDNF levels in patients with schizophrenia. However, there are restricted data in the literature that compare the serum BDNF levels in patients with deficit and nondeficit syndromes. In this study, we aimed to compare the serum BDNF levels between schizophrenic patients with deficit or nondeficit syndrome and healthy controls.

METHODS

After fulfilling the inclusion and exclusion criteria, 58 patients with schizophrenia and 36 healthy controls were included in the study. The patients were grouped as deficit syndrome (N=23) and nondeficit syndrome (N=35) according to the Schedule for the Deficit Syndrome. Three groups were compared in terms of the sociodemographic and clinical variants and serum BDNF levels.

RESULTS

The groups were similar in terms of age, sex, body mass index, and smoking status. The serum BDNF levels in patients with deficit syndrome were significantly lower than those in healthy controls. In contrast, the serum BDNF levels in patients with nondeficit syndrome were similar to those in healthy controls.

CONCLUSION

This study suggests that decreased BDNF levels may play a role in the pathophysiology of schizophrenic patients with deficit syndrome. Nonetheless, additional studies using a larger patient sample size are needed to investigate the serum BDNF levels in schizophrenic patients with deficit syndrome.

Diverse glial cell line-derived neurotrophic factor (GDNF) support between mania and schizophrenia: a comparative study in four major psychiatric disorders

BACKGROUND

Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) have essential roles in synaptic plasticity which is involved in pathogenesis and treatment of psychiatric disorders. However, it is not clear whether they act simultaneously during illness states in major psychiatric disorders.

METHODS

BDNF and GDNF serum levels were measured concomitantly by enzyme-linked immunosorbent assay (ELISA) method in 171 patients diagnosed with schizophrenia (n=33), bipolar disorder-manic episode (n=39), bipolar/unipolar depression (n=64, 24/40) and obsessive-compulsive disorder (n=35) according to DSM-IV, and 78 healthy volunteers. SCID-I and SCID non-patient version were used for clinical evaluation of the patients and healthy volunteers, respectively. Correlations between the two trophic factor levels, and illness severity scores, duration of illness and medication dosages were studied across different illnesses.

RESULTS

While patients had equally lower BDNF levels in all diagnoses, GDNF levels were significantly higher in mania and lower in schizophrenia compared to healthy controls. BDNF levels were negatively correlated to illness severity scores in affective episodes (mania and depression). Longer duration of illness (>5 years) had an impact on lower GDNF levels in schizophrenia. BDNF levels and antipsychotic drug dosages in schizophrenia, and GDNF levels and antidepressant drug dosages in obsessive-compulsive disorder were positively correlated.

CONCLUSION

Our data confirmed the evidence of equally deficient neuronal support by BDNF in all major psychiatric illnesses, but suggested a diverse glial functioning between schizophrenia and mania.

Comparison of serum BDNF levels in deficit and nondeficit chronic schizophrenia and healthy controls

The aim of this study was to compare serum BDNF levels of chronic schizophrenic patients, with or without deficit syndrome, and healthy controls. A comparative study of serum BDNF levels, determined by ELISA, was performed in 47 chronic patients with schizophrenia matched with 47 healthy controls. A part of the chronic schizophrenic sample was further divided into patients with a deficit (n=14) and a nondeficit syndrome (n=20), according to the Proxy for the Deficit Syndrome Scale. A significant difference was observed in decreased serum BDNF levels between chronic schizophrenia and healthy controls. No statistical significant differences in BDNF levels between deficit and nondeficit chronic schizophrenic patients were found. Our study confirms differences of serum BDNF levels of chronic schizophrenia and healthy controls, which correspond to the clinical progression of the disease. Our results do not support a relation between deficit profile in chronic schizophrenia and lower serum BDNF levels.

Can BDNF and IL-2 be indicators for the diagnosis in schizophrenic patients with depressive symptoms?

OBJECTIVE

The aim of the current study is to determine whether serum levels of brain-derived neurotrophic factor (BDNF) and interleukin-2 (IL-2) can be biological indicators for the diagnosis of schizophrenia in patients with depressive symptoms.

METHOD

Forty-seven patients (11 patients diagnosed with schizophrenia, 16 patients diagnosed with schizophrenia and comorbid depression and 20 patients diagnosed with major depressive disorder) and 20 healthy subjects were enrolled. The Positive and Negative Symptoms Scale, the Calgary Depression Scale for Schizophrenia and the Hamilton Depression Rating Scale were used for assessment. The serum BDNF and IL-2 levels of all the subjects were studied.

RESULTS

Decreased levels of serum BDNF and increased levels of serum IL-2 were found in the patients diagnosed with either schizophrenia, schizophrenia with depression, or major depressive disorder (p = 0.049, p = 0.010; p = 0.001 and p = 0.044; p = 0.027, p = 0.003; respectively) compared with control group. There were no significant differences between the patient groups in their serum BDNF and IL-2 levels.

CONCLUSIONS

The present study suggests that neurotrophic factors and immune system changes are involved in the pathogenesis of schizophrenia with or without depressive symptomatology. However, the data do not clarify whether depressive symptoms in schizophrenia occur as a dimension of schizophrenia or as symptoms of major depression that is comorbid with schizophrenia.