Brain-derived neurotrophic factor levels in schizophrenia: a systematic review with meta-analysis

Treatments for weight gain in schizophrenia

PURPOSE OF REVIEW

Obesity and related metabolic disorders are extremely common in psychiatric patients, particularly in those with schizophrenia. Elucidating this link's neurobiology may inform clinicians and researchers of rational therapeutic approaches necessary to optimize clinical outcomes.

RECENT FINDINGS

Current literature highlights the pivotal role of the inflammation-oxidative stress-insulin resistance loop in the pathophysiology of both metabolic and neuropsychiatric disorders. The concept of 'diabetophrenia' is put forward to highlight the overlapping neurobiological mechanisms underlying metabolic dysfunction and schizophrenia symptoms. Innovative treatments, including the combination of xanomeline with trospium and incretin-based medicines, demonstrate encouraging potential in addressing such complex health challenges.

SUMMARY

The nuanced dynamics of chronic inflammation and psychiatric symptomatology underscore the significance of addressing both metabolic and mental health factors in a cohesive fashion while considering unique psychosocial contexts, dietary preferences, and lifestyle choices. A multidisciplinary strategy is essential for incorporating counseling, dietary interventions, behavioral therapies, and pharmacotherapy into the management of schizophrenia. The ensuing enhanced collaboration among healthcare professionals may render obsolete the prevailing siloed conceptualizations of mental disorders, opening new vistas for generating synergistic insights into the mind-body systems and leading to improved health and quality of life for patients with schizophrenia and other psychiatric conditions.

Neuroendocrine characterization into schizophrenia: norepinephrine and melatonin as promising biomarkers

Background

Although brain-derived neurotrophic factor (BDNF)has garnered extensive attention as a neuroendocrine marker in schizophrenia (SZ), its clinical utility remains limite due to inconsistent findings.

Methods

To address this gap, serum samples were collected from 24 female patients with SZ and 25 healthy controls. The metabolic profiling was performed using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) to capture abroad range of metabolites.

Results

Our results revealed that BDNF is not a robust discriminatory biomarker. Marked differences in metabolic profiles were identified between patients with SZ and healthy individuals. The GC-MS analysis revealed significant differences in 79 metabolites; while the LC-MS analysis identified 419 significantly differential metabolites. Functional analysis reveals that these differential metabolites predominantly contribute to metabolic and neuro-related processes. Our findings demonstrate that norepinephrine and melatonin, two additional neuroendocrine compounds, are significantly elevated in patients with SZ compared to healthy controls. Notably, their higher areas under the curve (AUC) values compared to BDNF highlight their potential as more reliable biomarkers for SZ.

Conclusion

This study offers valuable insights into the altered metabolic patterns of female patients with SZ and establishes melatonin and norepinephrine as promising neuroendocrine biomarkers, underscoring their diagnostic value and role in the neuroendocrine regulation of mental disorders.

Light Treatment Ameliorates Sub-chronic MK-801-Induced Cognitive Deficits in Mice Through Up-regulating BDNF/p-CREB/p-ERK Signaling Pathway

Cognitive impairment associated with schizophrenia (CIAS) is considered a core symptom of the illness, yet effective treatments remain limited. Light plays an important role in regulating cognitive functions. However, the potential of light treatment (LT) to improve CIAS remains unknown. The current study aimed to investigate the efficacy of LT on CIAS and explore the underlying molecular mechanisms in a CIAS animal model. The CIAS group and the control group were sub-chronically administered MK-801 and saline, respectively. Concurrently, the LT/CIAS group, consisting of CIAS mice, received LT exposure (3000 Lux, 2 h/day, for 3 weeks). Results showed a significant enhancement in cognitive performance among LT/CIAS mice, as evidenced by improvements in the novel object recognition (NOR) test, novel location recognition (NLR) test, and Morris water maze (MWM) compared to the CIAS group. Remarkably, these beneficial effects of LT persisted for over 4 weeks after the termination of LT. Furthermore, Golgi-cox staining unveiled an increased dendritic spine density and enhanced morphological complexity in hippocampal CA1 pyramidal neurons following 3 weeks of LT. Subsequent investigations revealed elevated levels of brain-derived neurotrophic factor (BDNF) and heightened phosphorylation of cAMP response element-binding phosphorylation protein (p-CREB) in the hippocampus of the LT/CIAS group compared to the CIAS group. Moreover, LT elevated the phosphorylated extracellular signal-regulated kinase (p-ERK) in the hippocampus of the LT/CIAS group relative to the CIAS group. In conclusion, the current study demonstrates that long-term LT effectively ameliorated sub-chronic MK-801-induced cognitive deficits in mice, and the altered dendritic spine density and morphology of CA1 pyramidal neurons were rescued in the LT/CIAS group, potentially through the up-regulation of the BDNF/p-CREB/p-ERK signaling pathway in LT/CIAS mice.

IUPHAR review - Novel therapeutic targets for schizophrenia treatment: A translational perspective

Schizophrenia is a severe and debilitating psychiatric disorder that profoundly impacts cognitive, emotional, and social functioning. Despite its devastating personal and societal toll, current treatments often provide only partial relief, underscoring the urgent need for innovative therapeutic strategies. This review explores emerging approaches that target the complex neurobiological underpinnings of schizophrenia, moving beyond traditional dopamine-centric models. Among these, some novel drugs still employ multimodal mechanisms, simultaneously targeting dopaminergic and serotonergic systems to enhance efficacy and tolerability. Given the well-documented excitatory/inhibitory imbalance in schizophrenia, significant efforts have been directed toward addressing NMDA receptor hypofunctionality. However, strategies targeting this pathway have yet to demonstrate consistent clinical efficacy. In contrast, therapies targeting the cholinergic system have shown greater promise. For instance, the xanomeline-trospium combination, which modulates muscarinic receptors, has recently gained approval, and other molecules with similar mechanisms are currently under development. Beyond these approaches, novel strategies are being explored to target innovative pathways, including neuroplasticity, neuroinflammation, and mitochondrial dysfunction. These efforts are often designed as part of a combinatorial strategy to enhance the efficacy of currently available antipsychotic drugs. Despite significant progress, challenges remain in translating experimental discoveries into effective clinical applications. Future research should prioritize biomarker-driven approaches and precision medicine to optimize individualized treatment outcomes. By integrating these emerging therapeutic targets, schizophrenia treatment may evolve toward a more comprehensive and personalized approach, addressing the disorder's full spectrum of symptoms and improving patient quality of life.

Cerebrolysin Induces Dendritic Tree Plastic Changes and BDNF Increase in the Amygdala of Male Rats with Maternal Deprivation

Several psychopathologies may be triggered, among other factors, by stress or trauma in childhood. The maternal deprivation model (MD) replicates some of the core factors that may induce the onset of different psychopathologies like structural and plasticity defects. Among other brain regions, the amygdala is susceptible to stress and trauma and plays a key role in integrating social behavior. Several molecules, such as Cerebrolysin® (CBL), have been used to treat different symptoms by reversing the underlying neurobiological plasticity-related changes. In this study, maternal deprivation (MD) was conducted on 9-day-old male Sprague-Dawley rats (n = 28; 7 rats per group: Intact, Intact + CBL, MD, and MD + CBL). At 25 postnatal days (PND), CBL treatment was administered for 10 consecutive days, and social behavior was evaluated in a three-chamber social test at 35 PND. Moreover, Sholl analysis and immunohistochemistry were carried out for dendritic intersection and brain-derived neurotrophic factor (BDNF) presence in the amygdala, respectively. CBL treatment had an augmentative effect on intact animals in terms of social behavior and incidences, but no differences between MD and CBL-treated animals. Moreover, dendritic intersections and BDNF decreased after the MD protocol but increased by CBL treatment in MD animals. Our results show that CBL could be part of the treatment in case of a traumatic or stressful event in neurodevelopment, especially in the youth age. According to this preclinical study, CBL could help reverse symptoms of different psychopathologies caused by stress or trauma, with neurobiological changes underlying its effect.

Psychedelics and schizophrenia: a double-edged sword

Psychedelics have shown promising effects in several psychiatric diseases as demonstrated by multiple clinical trials. However, no clinical experiments on patients with schizophrenia have been conducted up to date, except for some old semi-anecdotal studies mainly performed in the time-span '50s-'60s. Notably, these studies reported interesting findings, particularly on the improvement of negative symptoms and social cognition. With no doubts the lack of modern clinical studies is due to the psychomimetic properties of psychedelics, a noteworthy downside that could worsen positive symptoms. However, a rapidly increasing body of evidence has suggested that the mechanisms of action of such compounds partially overlaps with the pathogenic underpinnings of schizophrenia but in an opposite way. These findings suggest that, despite being a controversial issue, the use of psychedelics in the treatment of schizophrenia would be based on a strong biological rationale. Therefore, the aim of our perspective paper is to provide a background on the old experiments with psychedelics performed on patients with schizophrenia, interpreting them in the light of recent molecular findings on their ability to induce neuroplasticity and modulate connectivity, the immune and TAARs systems, neurotransmitters, and neurotropic factors. No systematic approach was adopted in reviewing the evidence given the difficulty to retrieve and interpret old findings. Interestingly, we identified a therapeutic potential of psychedelics in schizophrenia adopting a critical point of view, particularly on negative symptoms and social cognition, and we summarized all the relevant findings. We also identified an eligible subpopulation of chronic patients predominantly burdened by negative symptoms, outlining possible therapeutic strategies which encompass very low doses of psychedelics (microdosing), carefully considering safety and feasibility, to pave the way to future clinical trials.

Glial Derived Neurotrophic Factor and Schizophrenia Spectrum Disorders: A Scoping Review

BACKGROUND

Psychotic disorders, characterized by altered brain function, significantly impair reality perception. The neurodevelopmental hypothesis suggests these disorders originate from early brain development disruptions. Glial-derived neurotrophic factor (GDNF) is crucial for neuronal survival and differentiation, especially in dopaminergic neurons, and shows promise in neurodegenerative and neuropsychiatric conditions.

OBJECTIVES

This scoping review aims to examine the role of GDNF in schizophrenia spectrum disorders and substance-induced psychoses, integrating knowledge on the neurobiological mechanisms and therapeutic potential of GDNF.

METHODS

A comprehensive literature search was conducted using PubMed and Scopus databases from January 2001 onwards. Data extraction focused on GDNF levels, cognitive function, antipsychotic treatment effects, and genetic studies.

RESULTS

The review included 25 studies (18 human, 7 animal). While some studies demonstrated inconsistent results regarding GDNF serum levels in schizophrenic patients, the majority reported correlations between GDNF levels and cognitive functions. Animal studies underscored GDNF's role in stress response, drug-induced neurotoxicity, and dopamine signaling abnormalities. Genetic studies revealed potential associations between GDNF gene polymorphisms and schizophrenia susceptibility, though findings were mixed.

DISCUSSION

GDNF plays a significant role in cognitive functions and neuroprotection in schizophrenia. The variability in study results underscores the complexity of GDNF's involvement. The therapeutic potential of GDNF in psychotic disorders remains unclear, necessitating further research to clarify its efficacy and safety.

CONCLUSION

This review emphasizes the importance of integrated biomarker strategies, gene therapy approaches, and precision medicine in advancing the understanding and treatment of psychotic disorders.

Understanding the potential mechanisms of disease modifying effects of physical activity and exercise in people with schizophrenia

Schizophrenia is a serious chronic mental health problem that usually starts during adolescence and early childhood. It is characterized by positive symptoms (delusions, hallucinations and grossly disorganized speech and behaviour), negative symptoms (apathy, isolation and diminished affect), and cognitive impairment that negatively affect quality of life. Its treatments include the use of pharmacological interventions, exercise, non-invasive brain stimulation and cognitive remediation training. Exercise is a very simple and cost-effective intervention. However, it is important the mechanisms of its effects are understood so that it can be trusted in clinical practice. In addition, understanding the mechanisms is important for its modification and safe use. Similarly, it may help provide the basis for invention of safe and cost-effective pharmacological or alternative therapies. From the literature, the mechanisms of diseases modifying effects of exercise seem to include increased cardiorespiratory fitness, biochemical changes (increased level of BDNF, increased N-acetylaspartate (NAA)/cr (creatine) ratio, decreased level of triglycerides, increased high density lipoprotein (HDL) and decreased salivary cortisol), structural changes (increase in cerebral volume, increased white matter integrity and increased cortical thickness) and anthropometric changes (reduced body weight and body mass index (BMI), increased muscular strength and decreased waist-hip ratio or waist circumference or hip circumference).

Brain-derived neurotrophic factor levels in perinatal depression: A systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aim to synthesize the available evidence and determine the overall brain-derived neurotrophic factor (BDNF) levels in individuals diagnosed with perinatal depression (PND).

METHODS

We performed a thorough search of electronic databases, including PubMed, Embase, PsycINFO, and Web of Science, from their start until April 30, 2023. Our search strategy involved using specific keywords and medical subject headings (MeSH) terms related to BDNF, perinatal, post-partum, and antepartum depression. In the meta-analysis, we employed a random-effects model, and subgroup analyses were conducted to investigate any variations in the results.

RESULTS

A total of 15 studies met the inclusion criteria, of which 10 were used in the quantitative analysis. The meta-analysis demonstrated a significant decrease in BDNF levels in both individuals with antepartum depression (SMD: -0.31; 95% CI: -0.48 to -0.13; p-value = 0.0008; I2 = 71%), and post-partum depression (SMD: -0.61; 95% CI: -0.99 to -0.22; p-value = 0.0002 I2 = 77%). Furthermore, a significantly higher rate of PND among individuals in the lowest BDNF quartile (OR: 2.64; 95% CI: 1.01 to 6.89; p-value = 0.05; I2 = 90%) was seen. The results of subgroup analyses showed a statistically significant effect of the depression assessment tool on overall heterogeneity between studies.

CONCLUSION

This systematic review and meta-analysis provide evidence of lower BDNF protein levels in individuals diagnosed with PND. The results indicate that BDNF dysregulation may play a part in the development of PND. More research is needed to understand the mechanisms behind this and explore potential therapeutic applications.

Brain-Derived Neurotrophic Factor (BDNF) as a Predictor of Treatment Response in Schizophrenia and Bipolar Disorder: A Systematic Review

Brain-derived neurotrophic factor (BDNF) is a potential biomarker of response to treatment in psychiatric disorders. As it plays a role in the pathophysiological development of schizophrenia and bipolar disorder, it is of interest to study its role in predicting therapeutic responses in both conditions. We carried out a systematic review of the literature, looking for differences in baseline BDNF levels and the Val66Met BDNF polymorphism in these disorders between responders and non-responders, and found information showing that the Val/Val genotype and higher baseline BDNF levels may be present in patients that respond successfully to pharmacological and non-pharmacological treatments. However, there is still limited evidence to support the role of the Val66Met polymorphism and baseline BDNF levels as predictors of treatment response.

BDNF: New Views of an Old Player in Traumatic Brain Injury

Traumatic brain injury is a common health problem affecting millions of people each year. BDNF has been investigated in the context of traumatic brain injury due to its crucial role in maintaining brain homeostasis. Val66Met is a functional single-nucleotide polymorphism that results in a valine-to-methionine amino acid substitution at codon 66 in the BDNF prodomain, which ultimately reduces secretion of BDNF. Here, we review experimental animal models as well as clinical studies investigating the role of the Val66Met single-nucleotide polymorphism in traumatic brain injury outcomes, including cognitive function, motor function, neuropsychiatric symptoms, and nociception. We also review studies investigating the role of BDNF on traumatic brain injury pathophysiology as well as circulating BDNF as a biomarker of traumatic brain injury.

Multitrait Analysis to Decipher the Intertwined Genetic Architecture of Neuroanatomical Phenotypes and Psychiatric Disorders

BACKGROUND

There is increasing evidence of shared genetic factors between psychiatric disorders and brain magnetic resonance imaging (MRI) phenotypes. However, deciphering the joint genetic architecture of these outcomes has proven to be challenging, and new approaches are needed to infer the genetic structures that may underlie those phenotypes. Multivariate analyses are a meaningful approach to reveal links between MRI phenotypes and psychiatric disorders missed by univariate approaches.

METHODS

First, we conducted univariate and multivariate genome-wide association studies for 9 MRI-derived brain volume phenotypes in 20,000 UK Biobank participants. Next, we performed various complementary enrichment analyses to assess whether and how univariate and multitrait approaches could distinguish disorder-associated and non-disorder-associated variants from 6 psychiatric disorders: bipolar disorder, attention-deficit/hyperactivity disorder, autism, schizophrenia, obsessive-compulsive disorder, and major depressive disorder. Finally, we conducted a clustering analysis of top associated variants based on their MRI multitrait association using an optimized k-medoids approach.

RESULTS

A univariate MRI genome-wide association study revealed only negligible genetic correlations with psychiatric disorders, while a multitrait genome-wide association study identified multiple new associations and showed significant enrichment for variants related to both attention-deficit/hyperactivity disorder and schizophrenia. Clustering analyses also detected 2 clusters that showed not only enrichment for association with attention-deficit/hyperactivity disorder and schizophrenia but also a consistent direction of effects. Functional annotation analyses of those clusters pointed to multiple potential mechanisms, suggesting in particular a role of neurotrophin pathways in both MRI phenotypes and schizophrenia.

CONCLUSIONS

Our results show that multitrait association signature can be used to infer genetically driven latent MRI variables associated with psychiatric disorders, thereby opening paths for future biomarker development.

The Influence of Intestinal Microbiota on BDNF Levels

The regulation of neurogenesis, the complex process of producing and differentiating new brain tissue cells, is influenced by a complex interaction of internal and external factors. Over the past decade, extensive research has been conducted on neurotrophins and their key role in adult neurogenesis, as well as their impact on diseases such as depression. Among neurotrophins, the brain-derived neurotrophic factor (BDNF) has been the subject of comprehensive studies on adult neurogenesis, and scientific evidence supports its necessity for neurogenesis in the subventricular zone of the hippocampus. A novel area of research is the emerging role of gut microbiota as a significant contributor to neurogenesis and neurotrophin production. Studies have shown that reduced BDNF levels can lead to mood disorders, which are observed in intestinal dysbiosis, characterized by an imbalance in the composition and quantity of the intestinal microbiota. There is evidence in the literature that there is a link between brain function and gut microbiota. Physical activity, and especially the regularity and intensity of exercise, is important in relation to the level of BDNF and the intestinal microbiota. Probiotics, prebiotics and physical activity may have a positive effect on the intestinal microbiota, and therefore also on the level of the brain-derived neurotrophic factor.

The importance of oxidative biomarkers in diagnosis, treatment, and monitoring schizophrenia patients

INTRODUCTION

The etiology of schizophrenia (SCZ), an incredibly complex disorder, remains multifaceted. Literature suggests the involvement of oxidative stress (OS) in the pathophysiology of SCZ.

OBJECTIVES

Determination of selected OS markers and brain-derived neurotrophic factor (BDNF) in patients with chronic SCZ and those in states predisposing to SCZ-first episode psychosis (FP) and ultra-high risk (UHR).

MATERIALS AND METHODS

Determination of OS markers and BDNF levels by spectrophotometric methods and ELISA in 150 individuals (116 patients diagnosed with SCZ or in a predisposed state, divided into four subgroups according to the type of disorder: deficit schizophrenia, non-deficit schizophrenia, FP, UHR). The control group included 34 healthy volunteers.

RESULTS

Lower activities of analyzed antioxidant enzymes and GSH and TAC concentrations were found in all individuals in the study group compared to controls (p < 0.001). BDNF concentration was also lower in all groups compared to controls except in the UHR subgroup (p = 0.01). Correlations were observed between BDNF, R-GSSG, GST, GPx activity, and disease duration (p < 0.02). A small effect of smoking on selected OS markers was also noted (rho<0.06, p < 0.03).

CONCLUSIONS

OS may play an important role in the pathophysiology of SCZ before developing the complete clinical pattern of the disorder. The redox imbalance manifests itself with such severity in individuals with SCZ and in a state predisposing to the development of this psychiatric disease that natural antioxidant systems become insufficient to compensate against it completely. The discussed OS biomarkers may support the SCZ diagnosis and predict its progression.

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Systematic Review and Meta-analysis of Exercise Interventions for Psychotic Disorders: The Impact of Exercise Intensity, Mindfulness Components, and Other Moderators on Symptoms, Functioning, and Cardiometabolic Health

BACKGROUND AND HYPOTHESIS

Exercise therapy has been shown to be an effective complementary treatment for patients with psychotic disorders. However, the specific impacts of different training modalities remain poorly understood. This article aims to quantitatively review the moderating influence of different exercise modalities, hypothesizing that higher exercise intensity as well as utilization of mindfulness-based exercise (MBE) components, will improve intervention outcomes.

STUDY DESIGN

PubMed, Web of Science, and PsycINFO were searched from 2010 to March 2022 for randomized controlled trials investigating exercise interventions in patients with psychotic disorders (preregistration: https://doi.org/10.17605/OSF.IO/J8QNS). Outcomes considered were positive/negative symptoms, Positive and Negative Syndrome Scale (PANSS) General Psychopathology/Total scores, depressive symptoms, psychosocial functioning, quality of life, cardiorespiratory fitness, and body mass index. Separate meta-analyses, including moderator analyses, were performed to evaluate the moderating influence of different training modalities.

STUDY RESULTS

Of 6653 studies, 40 (n = 2111 patients) were included in the meta-analysis. The effects of moderate-intensity exercise exceed low-intensity approaches for PANSS Total scores (P = .02) and depressive symptoms (P = .04). The presence of MBE components was associated with improvements in positive symptoms (P = .04) and PANSS General Psychopathology subscores (P = .04) but also with higher error and between-study heterogeneity. Our analysis also shows improved intervention effects on depression in younger patients (P = .012) and improved psychosocial functioning scores following more frequent sessions (P < .01).

CONCLUSIONS

A minimum of moderate intensity should be considered. More frequent training sessions per week also seem to be beneficial. While adding mindfulness elements is promising, it increases heterogeneity and requires caution in terms of generalization.

Novel α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) potentiator LT-102: A promising therapeutic agent for treating cognitive impairment associated with schizophrenia

AIMS

We aimed to evaluate the potential of a novel selective α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) potentiator, LT-102, in treating cognitive impairments associated with schizophrenia (CIAS) and elucidating its mechanism of action.

METHODS

The activity of LT-102 was examined by Ca2+ influx assays and patch-clamp in rat primary hippocampal neurons. The structure of the complex was determined by X-ray crystallography. The selectivity of LT-102 was evaluated by hERG tail current recording and kinase-inhibition assays. The electrophysiological characterization of LT-102 was characterized by patch-clamp recording in mouse hippocampal slices. The expression and phosphorylation levels of proteins were examined by Western blotting. Cognitive function was assessed using the Morris water maze and novel object recognition tests.

RESULTS

LT-102 is a novel and selective AMPAR potentiator with little agonistic effect, which binds to the allosteric site formed by the intradimer interface of AMPAR's GluA2 subunit. Treatment with LT-102 facilitated long-term potentiation in mouse hippocampal slices and reversed cognitive deficits in a phencyclidine-induced mouse model. Additionally, LT-102 treatment increased the protein level of brain-derived neurotrophic factor and the phosphorylation of GluA1 in primary neurons and hippocampal tissues.

CONCLUSION

We conclude that LT-102 ameliorates cognitive impairments in a phencyclidine-induced model of schizophrenia by enhancing synaptic function, which could make it a potential therapeutic candidate for CIAS.

Symptomatic remission and recovery in major psychosis: Is there a role for BDNF? A secondary analysis of the LABSP cohort data

Remission, relapse prevention, and clinical recovery are crucial areas of interest in schizophrenia (SCZ) research. Although SCZ is a chronic disorder with poor overall outcomes, years of research demonstrated that recovery is possible. There are considerable data linking brain-derived neurotrophic factor (BDNF) to SCZ, however, evidence on the role of BDNF in remission in SCZ is scarce. This secondary analysis of the Longitudinal Assessment of BDNF in Sardinian patients (LABSP) data aimed to investigate the relationship between serum BDNF levels and symptomatic remission, simultaneous clinical and functional remission, and recovery in patients with SCZ. A total of 105 patients with SCZ or schizoaffective disorder were recruited for a longitudinal assessment of BDNF levels over 24 months. Longitudinal data were analyzed using mixed-effects linear regression models. The study found significant associations between use of long acting injectables (χ2 = 7.075, df = 1, p = 0.008), baseline serum BDNF levels (U = 701, z = -2.543, p = 0.011), and "childhood" (U = 475, z = -2.124, p = 0.034) and "general" (U = 55, z = -2.014, p = 0.044) subscales of the Premorbid Adjustment Scale (PAS) with patients maintaining remission and recovery. The diagnosis of SCZ was significantly associated with lower BDNF levels for patients with simultaneous clinical and functional remission (Z = 2.035, p = 0.0419) and recovery (Z = 2.009, p = 0.0445) compared to those without. There were no significant associations between remission in the entire sample and longitudinal serum BDNF levels or genetic variants within the BDNF gene. These findings provide further insight into the complex relationship between BDNF and SCZ.

Stress, Environment and Early Psychosis

Existing literature provides extended evidence of the close relationship between stress dysregulation, environmental insults, and psychosis onset. Early stress can sensitize genetically vulnerable individuals to future stress, modifying their risk for developing psychotic phenomena. Neurobiological substrate of the aberrant stress response to hypothalamic-pituitary-adrenal axis dysregulation, disrupted inflammation processes, oxidative stress increase, gut dysbiosis, and altered brain signaling, provides mechanistic links between environmental risk factors and the development of psychotic symptoms. Early-life and later-life exposures may act directly, accumulatively, and repeatedly during critical neurodevelopmental time windows. Environmental hazards, such as pre- and perinatal complications, traumatic experiences, psychosocial stressors, and cannabis use might negatively intervene with brain developmental trajectories and disturb the balance of important stress systems, which act together with recent life events to push the individual over the threshold for the manifestation of psychosis. The current review presents the dynamic and complex relationship between stress, environment, and psychosis onset, attempting to provide an insight into potentially modifiable factors, enhancing resilience and possibly influencing individual psychosis liability.

Effect of cannabis use on blood levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF): A systematic review and meta-analysis

BACKGROUND

The impact of cannabis uses on blood levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) remains uncertain, with conflicting findings reported in the literature. BDNF and NGF both are essential proteins for neuron's growth, and their dysregulation is seen in various mental disorders. This study aims to evaluate the relationship between cannabis usage and BDNF and NGF levels due to their potential implications for mental health.

METHODS

A comprehensive search of electronic databases was performed using appropriate MeSH terms and keywords. Inclusion criteria comprised human studies investigating the relationship between cannabis use and BDNF and NGF levels.

RESULTS

A total of 11 studies met the inclusion criteria and were included. The pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of BDNF (random-effects model, standardized mean differences [SMD] = .26, 95% CI -.34 to .76, p = .40). The results of our subgroup analysis based on BDNF source showed a nonsignificant between-group difference. For NGF levels, four studies were included, the pooled analysis revealed a nonsignificant association between cannabis use and dysregulated blood levels of NGF (random-effects model, SMD = -.60, 95% CI -1.43 to -.23, p = .16). In both analyses, high heterogeneity was observed among the included studies which is a notable limitation to current meta-analysis.

CONCLUSION

This systematic review highlights the need for further research to elucidate the relationship between cannabis use and these neurotrophic factors. A better understanding of these associations can contribute to our knowledge of the neurobiological effects of cannabis and inform potential implications for mental health, cognitive function, and neurodegenerative disorders.

The Effects of Curcumin on Brain-Derived Neurotrophic Factor Expression in Neurodegenerative Disorders

Brain-Derived Neurotrophic Factor (BDNF) is a crucial molecule implicated in plastic modifications related to learning and memory. The expression of BDNF is highly regulated, which can lead to significant variability in BDNF levels in healthy subjects. Changes in BDNF expression might be associated with neuropsychiatric diseases, particularly in structures important for memory processes, including the hippocampus and parahippocampal areas. Curcumin is a natural polyphenolic compound that has great potential for the prevention and treatment of age-related disorders by regulating and activating the expression of neural protective proteins such as BDNF. This review discusses and analyzes the available scientific literature on the effects of curcumin on BDNF production and function in both in vitro and in vivo models of disease.

Biomarkers for Psychosis: Are We There Yet? Umbrella Review of 1478 Biomarkers

Background and Hypothesis

This umbrella review aims to comprehensively synthesize the evidence of association between peripheral, electrophysiological, neuroimaging, neuropathological, and other biomarkers and diagnosis of psychotic disorders.

Study Design

We selected systematic reviews and meta-analyses of observational studies on diagnostic biomarkers for psychotic disorders, published until February 1, 2018. Data extraction was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Evidence of association between biomarkers and psychotic disorders was classified as convincing, highly suggestive, suggestive, weak, or non-significant, using a standardized classification. Quality analyses used the Assessment of Multiple Systematic Reviews (AMSTAR) tool.

Study Results

The umbrella review included 110 meta-analyses or systematic reviews corresponding to 3892 individual studies, 1478 biomarkers, and 392 210 participants. No factor showed a convincing level of evidence. Highly suggestive evidence was observed for transglutaminase autoantibodies levels (odds ratio [OR] = 7.32; 95% CI: 3.36, 15.94), mismatch negativity in auditory event-related potentials (standardized mean difference [SMD] = 0.73; 95% CI: 0.5, 0.96), P300 component latency (SMD = -0.6; 95% CI: -0.83, -0.38), ventricle-brain ratio (SMD = 0.61; 95% CI: 0.5, 0.71), and minor physical anomalies (SMD = 0.99; 95% CI: 0.64, 1.34). Suggestive evidence was observed for folate, malondialdehyde, brain-derived neurotrophic factor, homocysteine, P50 sensory gating (P50 S2/S1 ratio), frontal N-acetyl-aspartate, and high-frequency heart rate variability. Among the remaining biomarkers, weak evidence was found for 626 and a non-significant association for 833 factors.

Conclusions

While several biomarkers present highly suggestive or suggestive evidence of association with psychotic disorders, methodological biases, and underpowered studies call for future higher-quality research.

Neurotrophic Factors in Cannabis-induced Psychosis: An Update

BACKGROUND

Cannabis is the most widely used illicit substance. Numerous scientific evidence confirm the strong association between cannabis and psychosis. Exposure to cannabis can induce the development of psychosis and schizophrenia in vulnerable individuals. However, the neurobiological processes underlying this relationship are unknown. Neurotrophins are a class of proteins that serve as survival factors for central nervous system (CNS) neurons. In particular, Nerve Growth Factor (NGF) plays an important role in the survival and function of cholinergic neurons while Brain Derived Neurotrophic Factor (BDNF) is involved in synaptic plasticity and the maintenance of midbrain dopaminergic and cholinergic neurons. Glial Cell Derived Neurotrophic Factor (GDNF) promotes the survival of midbrain dopaminergic neurons and Neuregulin 1 (NrG- 1) contributes to glutamatergic signals regulating the N-methyl-D-aspartate (NMDA). They have a remarkable influence on the neurons involved in the Δ-9-THC (tethra-hydro-cannabinol) action, such as dopaminergic and glutamatergic neurons, and can play dual roles: first, in neuronal survival and death, and, second, in activity-dependent plasticity.

METHODS

In this brief update, reviewing in a narrative way the relevant literature, we will focus on the effects of cannabis on this class of proteins, which may be implicated, at least in part, in the mechanism of the psychostimulant-induced neurotoxicity and psychosis.

CONCLUSION

Since altered levels of neurotrophins may participate in the pathogenesis of psychotic disorders which are common in drug users, one possible hypothesis is that repeated cannabis exposure can cause psychosis by interfering with neurotrophins synthesis and utilization by CNS neurons.

Plasma biomarkers in adolescents with schizophrenia-spectrum disorder

AIM

Schizophrenia onset in the developmental age has a strong neurodevelopmental burden and is associated with a poorer prognosis. The approach to diagnosis is still based on symptomatic description without objective validation. In this study, we aimed to compare the peripheral blood levels of hypothesized biomarker proteins: brain-derived neurotrophic factor (BDNF), proBDNF, p75 neurotrophin receptor (p75NTR ) and S100B between early-onset schizophrenia-spectrum adolescents (n = 45) and healthy controls (n = 34).

METHODS

Clinical assessment of the participants encompassed symptomatic description with the use of structured interviews and executive function objective measurement. Plasma levels of BDNF protein were significantly lower in schizophrenia patients than in controls both at admission (p = .003) and 6-8 weeks follow-up (p = .007).

RESULTS

We observed significant correlations between BDNF, proBDNF and p75NTR levels and positive and negative symptoms scale (PANSS) scores, p75NTR and S100B levels and suicidal parameters, as well as a correlation of BDNF plasma level with the risky decision-making style in Iowa Gambling Task (IGT).

CONCLUSIONS

The results indicate a potential value of studied proteins as a biomarker in the diagnosis and monitoring of the disease's course.

The relationship between the brain-derived neurotrophic factor and neurocognitive response to physical exercise in individuals with schizophrenia

OBJECTIVE

Physical exercise can improve neurocognition in individuals with schizophrenia, presumably by facilitating neuroplasticity. There is, however, large inter-individual variation in response. The brain-derived neurotrophic factor (BDNF) has been proposed to mediate these effects. The current aim was to investigate the sparsely studied relationship between peripheral resting BDNF and neurocognitive response to physical exercise in individuals with schizophrenia.

METHOD

The current study reports secondary analyses of data from a randomized controlled trial (RCT), ClinicalTrials.gov number 02205684, recently reported according to the CONSORT guidelines. Eighty-two individuals with schizophrenia (mean age 37 ± 14 years old, 61% men) were randomly allocated to high-intensity interval training (HIIT) or a comparison group performing low-intensity active video gaming (AVG). Both interventions consisted of 2 sessions/week for 12 weeks. In previously published primary RCT analyses, HIIT and AVG showed comparable small to moderate improvements in neurocognition. We now address the inter-individual variability in neurocognitive response. We apply mediation and moderation analyses for repeated measures designs (MEMORE) and mixed effects models.

RESULTS

Baseline neurocognition was not significantly correlated with baseline levels of mature BDNF (baseline-mBDNF) or the precursor proBDNF. Nonetheless, baseline-mBDNF, but not baseline proBDNF, moderated the effect of exercise on neurocognition (p = 0.025) and explained 7% of the variance. The neurocognitive improvement increased with increasing baseline-mBDNF values. The moderating effect of baseline-mBDNF remained significant in a more complex model adding the moderating effects of exercise mode, sex, age, duration of illness and baseline VO2max on the outcome (neurocognition). Mean baseline-mBDNF significantly decreased from baseline to post-intervention (p = 0.036), regardless of exercise mode, differing by sex and associated with improved VO2max but not with change in neurocognition. A mediating role of mBDNF on the effect of physical exercise on neurocognition was not supported. Values of proBDNF mainly remained stable from baseline to post-intervention.

CONCLUSION

We found that baseline-mBDNF moderated the effect of physical exercise on neurocognition in individuals with schizophrenia and explained a small part of the inter-individual variation in neurocognitive response. Mean mBDNF decreased from baseline to post-intervention, regardless of exercise mode. A mediating role of mBDNF on the effect of exercise on neurocognition was not supported. The inter-individual variation in neurocognitive response and the complex role of peripheral BDNF in physical exercise is still to be elucidated.

The Gut-Brain Axis in Schizophrenia: The Implications of the Gut Microbiome and SCFA Production

Schizophrenia, a severe mental illness affecting about 1% of the population, manifests during young adulthood, leading to abnormal mental function and behavior. Its multifactorial etiology involves genetic factors, experiences of adversity, infection, and gene-environment interactions. Emerging research indicates that maternal infection or stress during pregnancy may also increase schizophrenia risk in offspring. Recent research on the gut-brain axis highlights the gut microbiome's potential influence on central nervous system (CNS) function and mental health, including schizophrenia. The gut microbiota, located in the digestive system, has a significant role to play in human physiology, affecting immune system development, vitamin synthesis, and protection against pathogenic bacteria. Disruptions to the gut microbiota, caused by diet, medication use, environmental pollutants, and stress, may lead to imbalances with far-reaching effects on CNS function and mental health. Of interest are short-chain fatty acids (SCFAs), metabolic byproducts produced by gut microbes during fermentation. SCFAs can cross the blood-brain barrier, influencing CNS activity, including microglia and cytokine modulation. The dysregulation of neurotransmitters produced by gut microbes may contribute to CNS disorders, including schizophrenia. This review explores the potential relationship between SCFAs, the gut microbiome, and schizophrenia. Our aim is to deepen the understanding of the gut-brain axis in schizophrenia and to elucidate its implications for future research and therapeutic approaches.

BDNF gene Val66Met polymorphisms as a predictor for clinical presentation in schizophrenia - recent findings

Schizophrenia is a highly heritable, severe psychiatric disorder that involves dysfunctions in thinking, emotions, and behavior, with a profound impact on a person's ability to function normally in their daily life. Research efforts continue to focus on elucidating possible genetic underlying mechanisms of the disorder. Although the genetic loci identified to date to be significantly associated with schizophrenia risk do not represent disease-causing factors, each one of them could be seen as a possible incremental contributor. Considering the importance of finding new and more efficient pharmacological approaches to target the complex symptomatology of this disorder, in this scoping review, we are focusing on the most recent findings in studies aiming to elucidate the contribution of one of the genetic factors involved - the BDNF gene Val66Met polymorphisms. Here we performed a systematic search in Pubmed, Embase, and Web of Science databases with the search terms: (BDNF gene polymorphism) AND (schizophrenia) for articles published in the last 5 years. To be selected for this review, articles had to report on studies where genotyping for the BDNF Val66Met polymorphism was performed in participants diagnosed with schizophrenia (or schizophrenia spectrum disorders or first-episode psychosis). The search provided 35 results from Pubmed, 134 results from Embase, and 118 results from the Web of Science database. Twenty-two articles were selected to be included in this review, all reporting on studies where an implication of the BDNF Val66Met polymorphisms in the disorder's pathophysiology was sought to be elucidated. These studies looked at BDNF gene Val66Met polymorphism variants, their interactions with other genes of interest, and different facets of the illness. The Met/Met genotype was found to be associated with higher PANSS positive scores. Furthermore, Met/Met homozygous individuals appear to present with worse cognitive function and lower levels of serum BDNF. In the Val/Val genotype carriers, increased BDNF levels were found to correlate with weight gain under Risperidone treatment. However, due to heterogeneous results, the diversity in study populations and studies' small sample sizes, generalizations cannot be made. Our findings emphasize the need for further research dedicated to clarifying the role of gene polymorphisms in antipsychotic treatment to enhance specificity and efficacy in the 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.

Plasma levels of neurotrophin 4/5, NGF and pro-BDNF influence transition to mental disorders in a sample of individuals at ultra-high risk for psychosis

BACKGROUND

Neurotrophins (NTs) and their precursors (pro-NTs) are polypeptides with important roles in neuronal development, differentiation, growth, survival and plasticity, as well as apoptosis and neuronal death. Imbalance in NT levels were observed in schizophrenia spectrum disorders, but evidence in ultra-high risk for psychosis (UHR) samples is scarce.

METHODS

A naturalistic sample of 87 non-help-seeking UHR subjects and 55 healthy controls was drawn from the general population. Blood samples were collected and NT-3, NT-4/5, BDNF, pro-BDNF, NGF, pro-NGF were analyzed through enzyme linked immunosorbent assay (ELISA). Information on cannabis and tobacco use was also collected. Logistic regression models and path analysis were used to control for confounders (tobacco, age, cannabis use).

RESULTS

NT-4/5 was significantly decreased, and pro-BDNF was significantly increased in UHR individuals compared to controls. Cannabis use and higher NGF levels were significantly related to transition to psychiatric disorders among UHR subjects. Increased pro-BDNF and decreased NT-4/5 influenced transition by the mediation of perceptual abnormalities.

CONCLUSIONS

Our study shows for the first time that NTs are altered in UHR compared to healthy control individuals, and that they can be a predictor of transition to psychiatric illnesses in this population. Future studies should employ larger naturalistic samples to confirm the findings.

The emerging role of exosomes in Schizophrenia

Schizophrenia (SCZ), a serious mental disorder, is one of the leading causes of disease burden worldwide. Exosomes, as a natural nanocarrier, are able to cross the blood-brain barrier (BBB) and play a key bridging role in central nervous system (CNS) communication, participating in important physiological processes such as neural regeneration, prominent plasticity, axonal support, and neuroinflammation. In recent years, exosomes have received widespread attention in the field of neurodegenerative diseases and mental disorders, especially Alzheimer's disease. However, there are few reviews on exosomes and SCZ. Therefore, we conducted a literature search in PubMed and Web of Science using the following search terms: "schizophrenia", "mental disorder", "central system", "exosome", "extracellular vesicles" to identify publications from January 2010 to December 2022. Our review summarized exosomes secreted by different cell types in the CNS and the double-edged role of exosomes in the development of SCZ, and discussed their future potential as biomarkers and therapeutic targets. In conclusion, this article provides an up-to-date overview of the current research on the involvement of exosomes in SCZ, while also highlighting the challenges that are currently faced in this field.

High blood levels of brain-derived neurotrophic factor (BDNF) mRNA in early psychosis are associated with inflammatory markers

The brain-derived neurotrophic factor (BDNF) single nucleotide polymorphism (SNP) rs6265C > T, Val66Met, affects BDNF secretion and has been related to inflammatory processes. Both the rs6265 and BDNF protein levels have been widely investigated in neuropsychiatric disorders with conflicting results. In the present study we examined BDNF mRNA expression in blood considering the SNP rs6265 and its relationship with inflammatory markers in the early stages of psychosis. The rs6265 genotype and blood BDNF mRNA levels were measured in 34 at-risk mental states (ARMS) individuals, 37 patients with first-episode psychosis (FEP) and 42 healthy controls (HCs) by quantitative PCR and reverse transcription (RT)-qPCR using validated TaqMan assays. We also obtained measures of interleukin-6 (IL6) mRNA levels, fibrinogen, neutrophil-to-lymphocyte ratio (NLR) and high-sensitivity C-reactive protein. We identified that BDNF mRNA levels were associated with the rs6265 genotype in an allele-dose-dependent manner, with low expression levels associated with the T allele (Met substitution). Thus, we controlled for the rs6265 genotype in all analyses. Blood BDNF mRNA levels differed between diagnostic groups: patients with FEP exhibited higher blood BDNF mRNA levels than ARMS individuals, and the lowest levels were observed in HC. In addition, we observed significant correlations between BDNF mRNA levels and inflammatory markers (IL6 mRNA levels and NLR), controlled by the rs6265 genotype, in ARMS and FEP groups. This exploratory study suggests that the rs6265 genotype is associated with differential blood mRNA expression of BDNF that increases with illness progression and correlated with inflammation in the early stages of psychosis.

Exercise as an Adjuvant Treatment of Schizophrenia: A Review

Schizophrenia is a chronic debilitating condition associated with impaired social functioning, memory, and executive functioning. To date, we are still unsure about the exact etiology of schizophrenia, but there are many factors, such as genetics, diminished hippocampal volume, and imbalance of neurotransmitters, that lead to the pathogenies of the disease. Antipsychotics are the most effective treatment option for schizophrenia so far, yet they are associated with a wide array of side effects, ranging from extrapyramidal side effects to conditions, such as metabolic syndrome. Exercise has been shown to increase neural connections in the brain, which can improve cognition and memory. This literature review focuses on the signs and symptoms of schizophrenia, its treatment options, and how exercise can help with some of the symptoms of schizophrenia, especially the negative symptoms that are least effectively treated by antipsychotics.

BDNF and Cognitive Function in Chilean Schizophrenic Patients

Despite cognitive symptoms being very important in schizophrenia, not every schizophrenic patient has a significant cognitive deficit. The molecular mechanisms underlying the different degrees of cognitive functioning in schizophrenic patients are not sufficiently understood. We studied the relation between brain-derived neurotrophic factor (BDNF) and cognitive functioning in two groups of schizophrenic patients with different cognitive statuses. According to the Montreal Cognitive Assessment (MoCA) results, the schizophrenic patients were classified into two subgroups: normal cognition (26 or more) and cognitive deficit (25 or less). We measured their plasma BDNF levels using ELISAs. The statistical analyses were performed using Spearman's Rho and Kruskal-Wallis tests. We found a statistically significant positive correlation between the plasma BDNF levels and MoCA score (p = 0.04) in the subgroup of schizophrenic patients with a cognitive deficit (n = 29). However, this correlation was not observed in the patients with normal cognition (n = 11) and was not observed in the total patient group (n = 40). These results support a significant role for BDNF in the cognitive functioning of schizophrenics with some degree of cognitive deficit, but suggest that BDNF may not be crucial in patients with a normal cognitive status. These findings provide information about the molecular basis underlying cognitive deficits in this illness.

Effects of curcumin nanodelivery on schizophrenia and glioblastoma

Curcumin is a natural polyphenol, which has a variety of pharmacological activities, including, antineoplastic, antioxidative and neuroprotective effects. Recent studies provided evidence for the bioactive role of curcumin in the prevention and treatment of various central nervous system (CNS)-related diseases including Parkinson's, Alzheimer's, Schizophrenia disease and glioma neoplasia. Schizophrenia is a disabling psychiatric disorder related with an aberrant functional coupling between hippocampus and prefrontal cortex that might be crucial for cognitive dysfunction. Animal studies have lent support to the hypothesis that curcumin could improve cognitive functioning and enhance cell proliferation of dentate gyrus. In relation to brain tumors, specifically gliomas, the antineoplastic action of curcumin is based on the inhibition of cell growth promoting apoptosis or autophagy and preventing angiogenesis. However, one of the main impediments for the application of curcumin to patients is its low bioavailability. In intracranial lesions, curcumin has problems to cross the blood-brain barrier (BBB). Currently nano-based drug delivery systems are opening a new horizon to tackle this problem. The bioavailability and effective release of curcumin can be made possible in the form of nanocurcumin. This nanoformulation preserves the properties of curcumin and makes it reach tissues with pathology. This review try to study the beneficial effects of the curcumin nanodelivery in central nervous pathologies such us schizophrenia and glioma disease.

Serum brain-derived neurotrophic factor levels in patients with schizophrenia and methamphetamine addiction: correlation with Mini-Mental State Examination (MMSE)

Methamphetamine use can induce psychosis resembling acute schizophrenia spectrum psychosis, making it challenging to differentiate between the two based on symptoms alone. Brain-derived neurotrophic factor (BDNF) exerts a critical role in hippocampal neural plasticity, influencing critical cognitive functions such as memory and learning. This study aimed to determine the role of serum BDNF levels in schizophrenia and methamphetamine addiction. A case-control study was conducted involving 50 patients with schizophrenia, 50 patients with methamphetamine addiction, and 50 healthy control subjects recruited from Ibn-Rushed Psychiatric Teaching Hospital in Baghdad. Cognitive impairment was assessed using the Mini-Mental State Examination (MMSE), while serum BDNF levels were measured using ELISA following standardized protocols. The findings revealed significantly lower median levels of BDNF (0.36 pg/ml) in patients with schizophrenia compared to both the control group (0.51 pg/ml) and the methamphetamine group (0.72 pg/ml). Moreover, there was a significant difference observed between the methamphetamine group and the control group. At a cut-off value of BDNF=0.37 pg/ml, the sensitivity and specificity of BDNF in differentiating between schizophrenia and methamphetamine addiction were 84% and 70%, respectively. Serum level of BDNF could be used to differentiate between schizophrenia and methamphetamine addiction when clinical distinctions are challenging to detect.

Genes implicated by a methylome-wide schizophrenia study in neonatal blood show differential expression in adult brain samples

Schizophrenia is a disabling disorder involving genetic predisposition in combination with environmental influences that likely act via dynamic alterations of the epigenome and the transcriptome but its detailed pathophysiology is largely unknown. We performed cell-type specific methylome-wide association study of neonatal blood (N = 333) from individuals who later in life developed schizophrenia and controls. Suggestively significant associations (P < 1.0 × 10-6) were detected in all cell-types and in whole blood with methylome-wide significant associations in monocytes (P = 2.85 × 10-9-4.87 × 10-9), natural killer cells (P = 1.72 × 10-9-7.82 × 10-9) and B cells (P = 3.8 × 10-9). Validation of methylation findings in post-mortem brains (N = 596) from independent schizophrenia cases and controls showed significant enrichment of transcriptional differences (enrichment ratio = 1.98-3.23, P = 2.3 × 10-3-1.0 × 10-5), with specific highly significant differential expression for, for example, BDNF (t = -6.11, P = 1.90 × 10-9). In addition, expression difference in brain significantly predicted schizophrenia (multiple correlation = 0.15-0.22, P = 3.6 × 10-4-4.5 × 10-8). In summary, using a unique design combining pre-disease onset (neonatal) blood methylomic data and post-disease onset (post-mortem) brain transcriptional data, we have identified genes of likely functional relevance that are associated with schizophrenia susceptibility, rather than confounding disease associated artifacts. The identified loci may be of clinical value as a methylation-based biomarker for early detection of increased schizophrenia susceptibility.

Schizophrenia, Curcumin and Minimizing Side Effects of Antipsychotic Drugs: Possible Mechanisms

Schizophrenia is a mental disorder characterized by episodes of psychosis; major symptoms include hallucinations, delusions, and disorganized thinking. More recent theories focus on particular disorders of interneurons, dysfunctions in the immune system, abnormalities in the formation of myelin, and augmented oxidative stress that lead to alterations in brain structure. Decreased dopaminergic activity and increased phospholipid metabolism in the prefrontal cortex might be involved in schizophrenia. Antipsychotic drugs used to treat schizophrenia have many side effects. Alternative therapy such as curcumin (CUR) can reduce the severity of symptoms without significant side effects. CUR has important therapeutic properties such as antioxidant, anti-mutagenic, anti-inflammatory, and antimicrobial functions and protection of the nervous system. Also, the ability of CUR to pass the blood-brain barrier raises new hopes for neuroprotection. CUR can improve and prevent further probable neurological and behavioral disorders in patients with schizophrenia. It decreases the side effects of neuroleptics and retains lipid homeostasis. CUR increases the level of brain-derived neurotrophic factor and improves hyperkinetic movement disorders. CUR may act as an added counteraction mechanism to retain cell integrity and defense against free radical injury. Thus it appears to have therapeutic potential for improvement of schizophrenia. In this study, we review several properties of CUR and its ability to improve schizophrenia and minimize the side effects of antipsychotic drugs, and we explore the underlying mechanisms by which CUR affects schizophrenia and its symptoms.

The Effects of Treatment in Psychotic Disorders-Changes in BDNF Levels and Clinical Outcomes: Systematic Review

Psychotic disorders are associated with significant impairment in functioning, and their treatment remains a great therapeutic challenge. Patients are at a higher risk of suicide and premature mortality. Biomarkers, such as brain-derived neurotrophic factor (BDNF), play a vital role in neurotransmission and neurodevelopment. Decreased levels of BDNF alter neuronal signaling and cause the appearance of symptoms such as the impairment of working memory. A literature search was performed using the PubMed data base. Following the inclusion and exclusion criteria, 24 original articles were selected. We collected available data showcasing the influence of antipsychotic and non-pharmacological treatments, in patients suffering from psychotic disorders, on clinical conditions and BDNF levels in serum or plasma. In this review, we outline emerging data regarding the influence of different antipsychotic drugs and non-pharmacological treatment methods on BDNF and discuss their role as predictors of treatment outcome. Most studies conducted with antipsychotics saw an increase in BDNF levels; however, no positive correlation between change in BDNF and PANSS scores was observed. Studies based on non-pharmacological methods varied based on the treatment applied. Therefore, it is difficult to draw definite conclusions.

The Role of Brain-Derived Neurotrophic Factor (BDNF) in Diagnosis and Treatment of Epilepsy, Depression, Schizophrenia, Anorexia Nervosa and Alzheimer's Disease as Highly Drug-Resistant Diseases: A Narrative Review

Brain-derived neurotrophic factor (BDNF) belongs to the family of neurotrophins, which are growth factors with trophic effects on neurons. BDNF is the most widely distributed neurotrophin in the central nervous system (CNS) and is highly expressed in the prefrontal cortex (PFC) and hippocampus. Its distribution outside the CNS has also been demonstrated, but most studies have focused on its effects in neuropsychiatric disorders. Despite the advances in medicine in recent decades, neurological and psychiatric diseases are still characterized by high drug resistance. This review focuses on the use of BDNF in the developmental assessment, treatment monitoring, and pharmacotherapy of selected diseases, with a particular emphasis on epilepsy, depression, anorexia, obesity, schizophrenia, and Alzheimer's disease. The limitations of using a molecule with such a wide distribution range and inconsistent method of determination are also highlighted.

Peripheral brain-derived neurotrophic factor (BDNF) and salivary cortisol levels in college students with different levels of academic stress. Study protocol

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) is essential for brain physiological processes influencing memory and learning. BDNF levels can be affected by many factors, including stress. Stress increase serum and salivary cortisol levels. Academic stress is of the chronic type. BDNF levels can be measure from serum, plasma or platelets, and there is still no standard methodology, which is relevant to ensure reproducibility and comparability between studies.

HYPOTHESIS

(i) BDNF concentrations in serum show greater variability than in plasma. (ii) In college students with academic stress, peripheral BDNF decreases and salivary cortisol increases.

GENERAL OBJECTIVE

To standardize plasma and serum collection for BDNF levels and to determine whether academic stress affects peripheral BDNF and salivary cortisol levels.

DESIGN

Quantitative research, with a non-experimental cross-sectional descriptive design.

PARTICIPANTS

Student volunteers. Under convenience sampling, 20 individuals will be included for standardization of plasma and serum collection and between 70 and 80 individuals to determine the effect of academic stress on BDNF and salivary cortisol.

PERIPHERAL BLOOD AND SALIVARY CORTISOL SAMPLING, MEASUREMENTS

12 mL of peripheral blood (with and without anticoagulant) will be drawn per participant, separated from plasma or serum and cryopreserved at -80°C. Additionally, they will be instructed in the collection of 1 mL of saliva samples, which will be centrifuged. Val66Met polymorphism will be performed by allele-specific PCR, while BDNF and salivary cortisol levels will be determined by ELISA.

STATISTICAL ANALYSIS

(i) descriptive analysis of the variables, through measures of central tendency and dispersion, and the categorical variables through their frequency and percentage. (ii) Then a bivariate analysis will be performed comparing groups using each variable separately.

EXPECTED RESULTS

We expect to (i) determine the analytical factors that allow a better reproducibility in the measurement of peripheral BDNF, and (ii) the effect of academic stress on BDNF and salivary cortisol levels.

BDNF Levels According to Variations in the CACNA1C Gene: Sex-Based Disparity

The CACNA1C gene encodes the pore-forming alpha-1c subunit of L-type voltage-gated calcium channels. The calcium influx through these channels regulates the transcription of the brain-derived neurotrophic factor (BDNF). Polymorphisms in this gene have been consistently associated with psychiatric disorders, and alterations in BDNF levels are a possible biological mechanism to explain such associations. Here, we sought to investigate the effect of the CACNA1C rs1006737 and rs4765913 polymorphisms and their haplotypes on serum BDNF concentration. We further aim to investigate the regulatory function of these SNPs and the ones linked to them. The study enrolled 641 young adults (362 women and 279 men) in a cross-sectional population-based survey. Linear regression was used to test the effects of polymorphisms and haplotypes on BDNF levels adjusted for potential confounders. Moreover, regulatory putative functional roles were assessed using in silico approach. BDNF levels were not associated with CACNA1C polymorphisms/haplotype in the total sample. When the sample was stratified by sex, checking the effect of polymorphisms on men and women separately, the A-allele of rs4765913 was associated with lower BDNF levels in women compared with the TT genotype (p = 0.010). The AA (rs1006737-rs4765913) haplotype was associated with BDNF levels in opposite directions regarding sex, with lower levels of BDNF in women (p = 0.040) compared to those without this haplotype, while with higher levels in men (p = 0.027). These findings were supported by the presence of regulatory marks only on the male fetal brain. Our results suggest that the BDNF levels regulation may be a potential mechanism underpinning the association between CACNA1C and psychiatric disorders, with a differential role in women and men.

Fingolimod ameliorates schizophrenia-like cognitive impairments induced by phencyclidine in male rats

BACKGROUND AND PURPOSE

Improvement of cognitive deficits in schizophrenia remains an unmet need owing to the lack of new therapies and drugs. Recent studies have reported that fingolimod, an immunomodulatory drug for treating multiple sclerosis, demonstrates anti-inflammatory and neuroprotective effects in several neurological disease models. This suggests its usefulness for ameliorating cognitive dysfunction in schizophrenia. Herein, we assessed the efficacy profile and mechanism of fingolimod in a rat model of phencyclidine (PCP)-induced schizophrenia.

EXPERIMENTAL APPROACH

Male Sprague-Dawley rats were treated with PCP for 14 days. The therapeutic effect of fingolimod on cognitive function was assessed using the Morris water maze and fear conditioning tests. Hippocampal neurogenesis and the expression of astrocytes and microglia were evaluated using immunostaining. Cytokine expression was quantified using multiplexed flow cytometry. Brain-derived neurotrophic factor expression and phosphorylation of extracellular signal-regulated kinase were determined using western blot analysis.

KEY RESULTS

Fingolimod attenuated cognitive deficits and restored hippocampal neurogenesis in a dose-dependent manner in PCP-treated rats. Fingolimod treatment exerted anti-inflammatory effects by inhibiting microglial activation and IL-6 and IL-1β pro-inflammatory cytokine expression. The underlying mechanism involves the upregulation of brain-derived neurotrophic factor protein expression and activation of the ERK signalling pathway.

CONCLUSION AND IMPLICATIONS

This is the first preclinical assessment of the effects of fingolimod on cognitive function in a model for schizophrenia. Our results suggest the immune system plays an crucial role in cognitive alterations in schizophrenia and highlight the potential of immunomodulatory strategies to improve cognitive deficits in schizophrenia.

Biomarkers in the diagnosis of neurodegenerative diseases

Biomarkers are molecules that behave as of biological states. Ideally, they should have high sensitivity, specificity, and accuracy in reflecting the total disease burden. The review discusses the current status of biomarkers used in neurological disorders. Neurodegenerative diseases are a heterogeneous group disorders characterized by progressive loss of structure and function of the central nervous system or peripheral nervous system. The review discusses the main biomarkers that have predictive value for describing clinical etiology, pathophysiology, and intervention strategies. Preciseness and reliability are one of important requirement for good biomarker. As a result of the analysis of literature data, it was revealed that beta-amyloid, total tau protein and its phosphorylated forms are the first biochemical biomarkers of neurodegenerative diseases measured in cerebrospinal fluid, but these markers are dependent upon invasive lumbar puncture and therefore it’s a cumbersome process for patients. Among the various biomarkers of neurodegenerative diseases, special attention is paid to miRNAs. MicroRNAs, important biomarkers in many disease states, including neurodegenerative disorders, make them promising candidates that may lead to identify new therapeutic targets. Conclusions. Biomarkers of neurological disease are present optimal amount in the cerebrospinal fluid but they are also present in blood at low levels. The data obtained reveal the predictive value of molecular diagnostics of neurodegenerative disorders and the need for its wider use.

Converging Evidence Points to BDNF as Biomarker of Depressive Symptoms in Schizophrenia-Spectrum Disorders

Brain-derived neurotrophic factor (BDNF) is a key modulator of neuroplasticity and has an important role in determining the susceptibility to severe psychiatric disorder with a significant neurodevelopmental component such as major psychoses. Indeed, a potential association between BDNF serum levels and schizophrenia (SCZ) and schizoaffective disorder (SAD) has been tested in diverse studies and a considerable amount of them found reduced BDNF levels in these disorders. Here, we aimed at testing the association of BDNF serum levels with several demographic, clinical, and psychometric measures in 105 patients with SCZ and SAD, assessing the moderating effect of genetic variants within the BDNF gene. We also verified whether peripheral BDNF levels differed between patients with SCZ and SAD. Our findings revealed that BDNF serum levels are significantly lower in patients affected by SCZ and SAD presenting more severe depressive symptomatology. This finding awaits replication in future independent studies and points to BDNF as a possible prognostic indicator in major psychoses.

Cognitive impairment in psychiatric diseases: Biomarkers of diagnosis, treatment, and prevention

Psychiatric diseases, such as schizophrenia, bipolar disorder, autism spectrum disorder, and major depressive disorder, place a huge health burden on society. Cognitive impairment is one of the core characteristics of psychiatric disorders and a vital determinant of social function and disease recurrence in patients. This review thus aims to explore the underlying molecular mechanisms of cognitive impairment in major psychiatric disorders and identify valuable biomarkers for diagnosis, treatment and prevention of patients.

Brain-Derived neurotrophic factor (BDNF) plasma level increases in patients with resistant schizophrenia treated with electroconvulsive therapy (ECT)

OBJECTIVES

The study aimed to assess the effect of Electroconvulsive Therapy (ECT) on plasma BDNF levels in patients with resistant schizophrenia.

METHODS

It was a cohort study that included 60 patients with resistant schizophrenia fulfilling the DSM-5 criteria of schizophrenia and APA criteria of resistant schizophrenia. They were divided into two groups, followed over 4 weeks, and compared to their baseline assessment. Group (A) included 45 patients who received 4-10 sessions of ECT while Group (B) included 15 patients who received the usual treatment with antipsychotics without ECT. The assessment included the severity of psychotic symptoms assessed by the Positive and Negative Symptom Scale (PANSS) in addition to plasma BDNF level.

RESULTS

Patients in Group (A) had an increased level of BDNF after treatment with a statistically significant difference in comparison to their baseline BDNF level (P = 0.027). Meanwhile, patients in group (B) showed a non-significant increase in BDNF. Patients in both groups improved significantly in all PANSS subscales after treatment.

CONCLUSIONS

It was concluded that plasma BDNF levels in patients with resistant schizophrenia increase after electroconvulsive therapy in association with clinical improvement.Key pointsBDNF increases after ECT treatment of resistant schizophrenia.BDNF is not correlated with the severity of psychotic symptomsPatients treated with ECT showed a better response.

Spironolactone alleviates schizophrenia-related reversal learning in Tcf4 transgenic mice subjected to social defeat

Cognitive deficits are a hallmark of schizophrenia, for which no convincing pharmacological treatment option is currently available. Here, we tested spironolactone as a repurposed compound in Tcf4 transgenic mice subjected to psychosocial stress. In this ‘2-hit’ gene by environment mouse (GxE) model, the animals showed schizophrenia-related cognitive deficits. We had previously shown that spironolactone ameliorates working memory deficits and hyperactivity in a mouse model of cortical excitatory/inhibitory (E/I) dysbalance caused by an overactive NRG1-ERBB4 signaling pathway. In an add-on clinical study design, we used spironolactone as adjuvant medication to the standard antipsychotic drug aripiprazole. We characterized the compound effects using our previously established Platform for Systematic Semi-Automated Behavioral and Cognitive Profiling (PsyCoP). PsyCoP is a widely applicable analysis pipeline based on the Research Domain Criteria (RDoC) framework aiming at facilitating translation into the clinic. In addition, we use dimensional reduction to analyze and visualize overall treatment effect profiles. We found that spironolactone and aripiprazole improve deficits of several cognitive domains in Tcf4tg x SD mice but partially interfere with each other’s effect in the combination therapy. A similar interaction was detected for the modulation of novelty-induced activity. In addition to its strong activity-dampening effects, we found an increase in negative valence measures as a side effect of aripiprazole treatment in mice. We suggest that repurposed drug candidates should first be tested in an adequate preclinical setting before initiating clinical trials. In addition, a more specific and effective NRG1-ERBB4 pathway inhibitor or more potent E/I balancing drug might enhance the ameliorating effect on cognition even further.

Paternal age and specific neurological soft signs as reliable and valid neurobiological markers for the diagnosis of patients with schizophrenia

Advanced parental age at delivery and neurological soft signs (NSS) constitute risk factors for schizophrenia. The aim of the current study was to develop a neurobiological diagnostic index by combining them, and without the contribution of clinical symptomatology. The study sample included 133 patients suffering from schizophrenia according to DSM-IV-TR (77 males and 56 females; aged 33.55 ± 11.22 years old) and 122 normal controls (66 males and 56 females; aged 32.89 ± 9.91 years old). The assessment included the Neurological Evaluation Scale (NES), and a number of scales assessing the clinical symptoms and adverse effects. The statistical analysis included exploratory t-test, Pearson Correlation coefficient (R) and Discriminant Function Analysis (DFA). Exploratory t-tests and Pearson's R suggested that sex, parental age and NSS constitute independent components. On the basis of DFA results, the Psychotic Neurological Index was developed. At the cut-off PNI score of 8.5, sensitivity was equal to 94.74 and specificity to 93.44. The current is probably the first study to report on an easily obtainable diagnostic neurobiological marker with identifiable properties which is absolutely independent from the clinical manifestations and could serve in distinguishing between patients with schizophrenia and healthy controls with high efficacy.

Association of serum brain-derived neurotrophic factor with hepatic enzymes, AST/ALT ratio, and FIB-4 index in middle-aged and older women

Substantial evidence suggests an important role of liver function in brain health. Liver function is clinically assessed by measuring the activity of hepatic enzymes in the peripheral blood. Brain-derived neurotrophic factor (BDNF) is an important regulator of brain function. Therefore, we hypothesized that blood BDNF levels are associated with liver function and fibrosis. To test this hypothesis, in this cross-sectional study, we investigated whether serum BDNF concentration is associated with liver enzyme activity, aspartate aminotransferase (AST)/ alanine aminotransferase (ALT) ratio, and fibrosis-4 (FIB-4) index in middle-aged and older women. We found that serum BDNF level showed a significant positive association with ALT and γ-glutamyltranspeptidase (GGT) activity and negative association with FIB-4 index, and a trend of negative association with the AST/ALT ratio after adjustment for age. Additionally, these associations remained statistically significant even after adjustment for body mass index (BMI) and fasting blood glucose level. These results demonstrate associations of serum BDNF levels with liver enzymes and hepatic fibrosis-related indices, which may underlie liver-brain interactions.