The Role of Cytokines in the Pathogenesis of Schizophrenia

Bartonella species bacteremia in association with adult psychosis

Introduction

The potential role of pathogens, particularly vector-transmitted infectious agents, as a cause of psychosis has not been intensively investigated. We have reported a potential link between Bartonella spp. bacteremia and neuropsychiatric symptoms, including pediatric acute onset neuropsychiatric syndrome and schizophrenia. The purpose of this study was to further assess whether Bartonella spp. exposure or infection are associated with psychosis.

Methods

In a blinded manner, we assessed the presence of anti-Bartonella antibodies by indirect immunofluorescence assays (IFA), and infection by amplification of bacterial DNA from blood by quantitative polymerase chain reaction (qPCR), digital PCR (dPCR), and droplet digital PCR (ddPCR) in 116 participants. Participants were categorized into one of five groups: 1) controls unaffected by psychosis (n = 29); 2) prodromal participants (n = 16); 3) children or adolescents with psychosis (n = 7); 4) adults with psychosis (n = 44); and 5) relatives of a participant with psychosis (n = 20).

Results

There was no significant difference in Bartonella spp. IFA seroreactivity between adults with psychosis and adult controls unaffected by psychosis. There was a higher proportion of adults with psychosis who had Bartonella spp. DNA in the bloodstream (43.2%) compared to adult controls unaffected by psychosis (14.3%, p = 0.021). The Bartonella species was determined for 18 of the 31 bacteremic participants, including infection or co-infection with Bartonella henselae (11/18), Bartonella vinsonii subsp. berkhoffii (6/18), Bartonella quintana (2/18), Bartonella alsatica (1/18), and Bartonella rochalimae (1/18).

Discussion

In conjunction with other recent research, the results of this study provide justification for a large national or international multi-center study to determine if Bartonella spp. bacteremia is more prevalent in adults with psychosis compared to adults unaffected by psychosis. Expanding the investigation to include a range of vector-borne and other microbial infections with potential CNS effects would enhance knowledge on the relationship between psychosis and infection.

Systems Genome: Coordinated Gene Activity Networks, Recurring Coordination Modules, and Genome Homeostasis in Developing Neurons

As human progenitor cells differentiate into neurons, the activities of many genes change; these changes are maintained within a narrow range, referred to as genome homeostasis. This process, which alters the synchronization of the entire expressed genome, is distorted in neurodevelopmental diseases such as schizophrenia. The coordinated gene activity networks formed by altering sets of genes comprise recurring coordination modules, governed by the entropy-controlling action of nuclear FGFR1, known to be associated with DNA topology. These modules can be modeled as energy-transferring circuits, revealing that genome homeostasis is maintained by reducing oscillations (noise) in gene activity while allowing gene activity changes to be transmitted across networks; this occurs more readily in neuronal committed cells than in neural progenitors. These findings advance a model of an "entangled" global genome acting as a flexible, coordinated homeostatic system that responds to developmental signals, is governed by nuclear FGFR1, and is reprogrammed in disease.

Eosinophils and Cognitive Impairment in Schizophrenia: A New Perspective

Schizophrenia is a complex psychiatric disorder characterized by a wide array of cognitive impairments. While research has predominantly focused on the neurological aspects of schizophrenia, emerging evidence suggests that the immune system, specifically eosinophils, may play a significant role in the cognitive deficits associated with the disorder. This review presents a novel perspective on the interplay between eosinophils and cognitive impairment in schizophrenia. Eosinophils, traditionally associated with allergic responses and inflammation, have garnered limited attention within the realm of neuropsychiatry. Recent studies have hinted at a potential link between eosinophil activation and the pathogenesis of schizophrenia. In this comprehensive review, we delve into the world of eosinophils, elucidating their nature, functions, and interactions with the immune system. We examine the cognitive deficits observed in individuals with schizophrenia and discuss existing theories on the etiology of these impairments, focusing on immune system involvement. The paper also highlights the evolving body of research that supports the idea of eosinophilic influence on schizophrenia-related cognitive deficits. Furthermore, we explore potential mechanisms through which eosinophils may exert their effects on cognitive function in schizophrenia, including interactions with other immune cells and inflammatory pathways. By discussing the clinical implications and potential therapeutic avenues stemming from this newfound perspective, we underscore the practical significance of this emerging field of research. While this paper acknowledges the limitations and challenges inherent in studying eosinophils within the context of schizophrenia, it serves as a posit for novel thought in this vexing disease space as well as a call to action for future research endeavors. By providing a comprehensive survey of the existing literature and posing unanswered questions, we aim to inspire a reimagining of the relationship between eosinophils and cognitive impairment in schizophrenia, ultimately advancing our understanding and treatment of this debilitating disorder.

Associations of Systemic Inflammation and Senescent Cell Biomarkers with Clinical Outcomes in Older Adults with Schizophrenia

Individuals with schizophrenia suffer from higher morbidity and mortality throughout life partly due to acceleration of aging-related diseases and conditions. Systemic inflammation is a hallmark of aging and is also observed in schizophrenia. An improved understanding of how inflammation and accelerated aging contribute to long-term health outcomes in schizophrenia could provide more effective treatments to preserve long-term cognitive and physical function. In this pilot cross-sectional study, 24 older adults (≥55 years old) with schizophrenia were assessed on symptoms (Positive and Negative Syndrome Scale), neurocognition (Matrics Consensus Cognitive Battery), mobility (Timed Get Up and Go), and general health (SF-12). Serum levels of 112 different cytokines were measured, from which we derived estimated senescence-associated secretory phenotype (SASP) scores for each participant. Two-tailed Pearson's bivariate correlations were computed to test the associations between schizophrenia clinical outcomes with individual cytokines, and SASP. Higher levels of eotaxin, IL-1α, IL-1β, and IFNα are associated with both worse PANSS negative and depressive symptoms scores. IL-1α and IL-1β negatively associated with general physical health whereas eotaxin negatively associated with mobility and global cognition. Overall, we found that specific inflammatory cytokines, but not composite measurements of SASP, are associated with clinical outcomes in older adults with schizophrenia.

Effects of Nostoc commune extract on the cerebral oxidative and neuroinflammatory status in a mice model of schizophrenia

Cyanobacterium Nostoc commune has long been used to alleviate various diseases. This research examines the effects of Nostoc commune extract (NCE) against behavioral disorders, cerebral oxidative stress, and inflammatory damage in the ketamine-induced schizophrenia model. Oral NCE administration (70 and 150 mg/kg/d) is performed after intraperitoneal ketamine injection (20 mg/kg) for 14 consecutive days. The forced swimming and open field tests are used to assess schizophrenia-like behaviors. After the behavioral test, dopamine (DA) level, oxidative stress markers, as well as the interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression are measured in the cerebral cortex. The results show that NCE treatment ameliorates KET-induced anxiety and depressive-like behaviors in OFT and FST, respectively. NCE considerably decreases the malondialdehyde (MDA) and DA levels and IL-6 and TNF-α expressions in mice with schizophrenia-like symptoms. Also, a significant increase is observed in the glutathione (GSH) level and catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GRx) activity in cerebral tissue. The present study shows that NCE treatment effectively improves KET-induced schizophrenia-like behaviors and oxidative and inflammatory damage. Therefore, NCE, via its bioactive constituents, could have strong neuroprotective effects in the schizophrenia-like model.

The neutrophil-to-Lymphocyte ratio is associated with clinical symptoms in first-episode medication-naïve patients with schizophrenia

Innate immunity has been shown to be associated with schizophrenia (Sch). This study explored the relationship between symptoms and neutrophil-to-lymphocyte ratio (NLR) (a marker of innate immunity) in patients with Sch. Ninety-seven first-episode medication-naïve (FEMN) patients with Sch and 65 healthy controls were recruited in this study. We measured the complete blood count and assessed the clinical symptoms using the PANSS scales. We found higher NEU counts and NLR in patients with Sch compared with control subjects. Male patients showed a higher NEU count than female patients. In addition, FEMN patients with higher NLR and NEU values showed higher PANSS-p, PANSS-g, and PANSS-total scores (all p < 0.05). Regression analysis revealed that NLR was a predictor for PANSS total scores in patients with Sch. Higher NLR value was observed in patients with Sch and the significant associations between NLR and psychotic symptoms indicate that an imbalance in inflammation and innate immune system may be involved in the pathophysiology of Sch.

IL-10 (-1082 G/A) polymorphism in Bataknese with schizophrenia

Objectives

Three biallelic polymorphisms at the promoter region of the interleukin-10 (IL-10) gene have been associated with susceptibility to schizophrenia. The aim of this case-control study was to investigate the association between IL-10 (-1082) G/A gene polymorphisms and schizophrenia among Bataknese, a native tribe inhabiting the North Sumatera province in Indonesia.

Methods

A total of 194 unrelated participants (n = 97 for each case and control groups) participated in this study. Polymerase chain reaction restriction fragment length polymorphism molecular genotyping was conducted to assess the genotype and allele distribution of IL-10 (-1082 G/A).

Results

Allele variations indicated that the dominant allele in the Batak tribe was allele A, whereas homozygous GG genotypes were not found in either group. The A allele and AA genotype were found to be risk factors for developing schizophrenia (OR = 2.26, 95% CI = 1.1825-4.3559 and OR = 2.56, 95% CI = 1.280-5.152, respectively).

Conclusion

Only the A allele and AA genotype of the IL-10 gene polymorphism at -1082 G/A contribute to schizophrenia susceptibility in Bataknese.

Genetic and inflammatory effects on childhood trauma and cognitive functioning in patients with schizophrenia and healthy participants

Recent studies have reported a negative association between exposure to childhood trauma, including physical neglect, and cognitive functioning in patients with schizophrenia. Childhood trauma has been found to influence immune functioning, which may contribute to the risk of schizophrenia and cognitive symptoms of the disorder. In this study, we aimed to test the hypothesis that physical neglect is associated with cognitive ability, and that this association is mediated by a combined latent measure of inflammatory response, and moderated by higher genetic risk for schizophrenia. The study included 279 Irish participants, comprising 102 patients and 177 healthy participants. Structural equation modelling was used to perform mediation and moderation analyses. Inflammatory response was measured via basal plasma levels of IL-6, TNF-α, and CRP, and cognitive performance was assessed across three domains: full-scale IQ, logical memory, and the emotion recognition task. Genetic variation for schizophrenia was estimated using a genome-wide polygenic score based on genome-wide association study summary statistics. The results showed that inflammatory response mediated the association between physical neglect and all measures of cognitive functioning, and explained considerably more variance than any of the inflammatory markers alone. Furthermore, genetic risk for schizophrenia was observed to moderate the direct pathway between physical neglect and measures of non-social cognitive functioning in both patient and healthy participants. However, genetic risk did not moderate the mediated pathway associated with inflammatory response. Therefore, we conclude that the mediating role of inflammatory response and the moderating role of higher genetic risk may independently influence the association between adverse early life experiences and cognitive function in patients and healthy participants.

ROI-based analysis of diffusion indices in healthy subjects and subjects with deficit or non-deficit syndrome schizophrenia

We analyzed DTI data involving 22 healthy subjects (HC), 15 patients with deficit syndrome schizophrenia (DSZ), and 25 patients with non-deficit syndrome schizophrenia (NDSZ). We used a 1.5-T MRI scanner to collect diffusion-weighted images and T1 images, which were employed to correct distortions and deformations within the diffusion-weighted images. For 156 regions of interest (ROI), we calculated the average fractional anisotropy (FA), mean diffusion (MD), and radial diffusion (RD). Each ROI underwent a group-wise comparison using permutation F-test, followed by post hoc pairwise comparisons with Bonferroni correction. In general, we observed lower FA in both schizophrenia groups compared to HC (i.e., HC>(DSZ=NDSZ)), while MD and RD showed the opposite pattern. Notably, specific ROIs with reduced FA in schizophrenia patients included bilateral nucleus accumbens, left fusiform area, brain stem, anterior corpus callosum, left rostral and caudal anterior cingulate, right posterior cingulate, left thalamus, left hippocampus, left inferior temporal cortex, right superior temporal cortex, left pars triangularis and right lingual gyrus. Significantly, the right cuneus exhibited lower FA in the DSZ group compared to other groups ((HC=NDSZ)>DSZ), without affecting MD and RD. These results indicate that compromised neural integrity in the cuneus may contribute to the pathophysiological distinctions between DSZ and NDSZ.

Study protocol for a randomized controlled trial with rituximab for psychotic disorder in adults (RCT-Rits)

BACKGROUND

The role of inflammation in the aetiology of schizophrenia has gained wide attention and research on the association shows an exponential growth in the last 15 years. Autoimmune diseases and severe infections are risk factors for the later development of schizophrenia, elevated inflammatory markers in childhood or adolescence are associated with a greater risk of schizophrenia in adulthood, individuals with schizophrenia have increased levels of pro-inflammatory cytokines compared to healthy controls, and autoimmune diseases are overrepresented in schizophrenia. However, treatments with anti-inflammatory agents are so far of doubtful clinical relevance. The primary objective of this study is to test whether the monoclonal antibody rituximab, directed against the B-cell antigen CD20 ameliorates psychotic symptoms in adults with schizophrenia or schizoaffective disorder and to examine potential mechanisms. A secondary objective is to examine characteristics of inflammation-associated psychosis and to identify pre-treatment biochemical characteristics of rituximab responders. A third objective is to interview a subset of patients and informants on their experiences of the trial to obtain insights that rating scales may not capture.

METHODS

A proof-of-concept study employing a randomised, parallel-group, double-blind, placebo-controlled design testing the effect of B-cell depletion in patients with psychosis. 120 participants with a diagnosis of schizophrenia spectrum disorders (SSD) (ICD-10 codes F20, F25) will receive either one intravenous infusion of rituximab (1000 mg) or saline. Psychiatric measures and blood samples will be collected at baseline, week 12, and week 24 post-infusion. Brief assessments will also be made in weeks 2 and 7. Neuroimaging and lumbar puncture, both optional, will be performed at baseline and endpoints. Approximately 40 of the patients and their informants will be interviewed for qualitative analyses on the perceived changes in well-being and emotional qualities, in addition to their views on the research.

DISCUSSION

This is the first RCT investigating add-on treatment with rituximab in unselected SSD patients. If the treatment is helpful, it may transform the treatment of patients with psychotic disorders. It may also heighten the awareness of immune-psychiatric disorders and reduce stigma.

TRIAL REGISTRATION

NCT05622201, EudraCT-nr 2022-000220-37 version 2.1. registered 14th of October 2022.

Interaction between high interleukin-2 and high cortisol levels is associated with psychopathology in patients with chronic schizophrenia

BACKGROUND

Both cortisol and interleukins appear at abnormal levels in schizophrenia. Our previous study has shown that cortisol and interleukins are associated with psychopathology and response to antipsychotic medications in a relatively small sample size of patients with schizophrenia. The current study was designed to investigate how cortisol, interleukins (ILs) and their interactions would correlate with clinical presentation in a relatively large sample size of patients with schizophrenia.

METHODS

We compared serum cortisol, IL-2, IL-6, and IL-8 levels in 162 medicated schizophrenia patients (including 27 patients in remission) and 62 healthy controls. Serum levels of cortisol and interleukins were measured by radioimmunoassay and quantitative ELISA, respectively. Clinical symptoms were assessed according to the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Patients with schizophrenia had significantly higher levels of cortisol and IL-2 compared to controls. Patients in remission had higher levels of IL-6 than non-remitting patients. PANSS positive symptoms, general psychopathology, cortisol and IL-2 were the most central nodes in the cortisol-IL-symptom network. The interaction between cortisol and IL-2 was associated with PANSS positive symptoms, general psychopathology and depressive factor. For patients with cortisol level above the median, IL-2 was negatively associated with PANSS positive symptoms and general psychopathology.

CONCLUSIONS

Our results indicated that the interaction between cytokines and cortisol may be associated with the pathophysiology of some symptoms in chronic schizophrenia. In particular, the interaction between cortisol and IL-2 is associated with the clinical phenotypes of schizophrenia.

Building Predictive Models for Schizophrenia Diagnosis with Peripheral Inflammatory Biomarkers

Machine learning and artificial intelligence technologies are known to be a convenient tool for analyzing multi-domain data in precision psychiatry. In the case of schizophrenia, the most commonly used data sources for such purposes are neuroimaging, voice and language patterns, and mobile phone data. Data on peripheral markers can also be useful for building predictive models. Here, we have developed five predictive models for the binary classification of schizophrenia patients and healthy individuals. Data on serum concentrations of cytokines, chemokines, growth factors, and age were among 38 parameters used to build these models. The sample consisted of 217 schizophrenia patients and 90 healthy individuals. The models architecture was involved logistic regression, deep neural networks, decision trees, support vector machine, and k-nearest neighbors algorithms. It was shown that the algorithm based on a deep neural network (consisting of five layers) showed a slightly higher sensitivity (0.87 ± 0.04) and specificity (0.52 ± 0.06) than other algorithms. Combining all variables into a single classifier showed a cumulative effect that exceeded the effectiveness of individual variables, indicating the need to use multiple biomarkers to diagnose schizophrenia. Thus, the data obtained showed the promise of using data on peripheral biomarkers and machine learning methods for diagnosing schizophrenia.

The Immunoseasonal Theory of Psychiatric Disorders

Although the influence of the weather on the well-being and mental health of psychiatric patients has been widely seen, the relationships between various seasonal weather factors and depressive, manic, anxiety, and psychotic states have not been systematized in the literature. The current article describes the seasonal changes in weather-related immune responses and their impact on the development of episodes of depression, mania, psychosis, and anxiety, highlighting the T-helper 1 (Th1) and Th2 immune balance as their potential trigger. In autumn-winter depression, the hyperactivation of the Th1 system, possibly by microbial/airborne pathogens, may lead to the inflammatory inhibition of prefrontal activity and the subcortical centers responsible for mood, drive, and motivation. Depressive mood periods are present in most people suffering from schizophrenia. In the spring and summertime, when the compensating anti-Th1 property of the Th2 immune system is activated, it decreases the Th1 response. In individuals immunogenetically susceptible to psychosis and mania, the inhibition of Th1 by the Th2 system may be excessive and lead to Th2-related frontal and subcortical hyperactivation and subsequent psychosis. In people suffering from bipolar disorder, hyperintense changes in white matter may be responsible for the partial activation of subcortical areas, preventing full paranoid psychosis. Thus, psychosis may be mood-congruent in affective disorders.

Interaction between peripheral and central immune markers in clinical high risk for psychosis

Neuroinflammatory events prior to the diagnosis of schizophrenia may play a role in transition to illness. To date only one in-vivo study has investigated this association between peripheral proinflammatory cytokines and brain markers of inflammation (e.g., mitochondrial 18 kDa translocator protein, TSPO) in schizophrenia, but none in its putative prodrome. In this study, we primarily aimed to (Barron et al., 2017) test study group (clinical high-risk (CHR) and healthy controls) differences in peripheral inflammatory markers and test for any associations with symptom measures, (Hafizi et al., 2017a) investigate the interaction between brain TSPO levels (dorsolateral prefrontal cortex (DLPFC) and hippocampus) and peripheral inflammatory clusters (entire cohort and (CHR) group independently) within a relatively large group of individuals at CHR for psychosis (N = 38) and healthy controls (N = 20). Participants underwent structural brain magnetic resonance imaging (MRI) and TSPO [18F]FEPPA positron emission tomography (PET) scans. Serum samples were assessed for peripheral inflammatory markers (i.e., CRP and interleukins). For exploratory analysis, we aimed to examine cluster differences for symptom measures and identify independent peripheral predictors of brain TSPO expression. Here, we report increased IL-8 levels that are positively correlated with prodromal general symptom severity and showed trend-level association with apathy in CHR. We identified distinct inflammatory clusters characterized by inflammatory markers (IL-1 β, IL-2, IFN-γ) that were comparable between entire cohort and CHR. TSPO levels did not differ between inflammatory clusters (entire cohort or CHR). Finally, we show that CRP, IL-1 β, TNF-α, and IFN-γ levels were the independent peripheral predictors of brain TSPO expression. Thus, alterations in brain TSPO expression in response to inflammatory processes are not evident in CHR. Taken together, clustering by inflammatory status is a promising strategy to characterize the interaction between brain TSPO and peripheral markers of inflammation.

Effects of a six-month yoga intervention on the immune-inflammatory pathway in antipsychotic-stabilized schizophrenia patients: A randomized controlled trial

BACKGROUND

Schizophrenia is a complex neuropsychiatric disorder for which several etiopathological theories have been proposed, one of the prominent ones being immune dysfunction. Recent studies on yoga as an add-on therapy have shown improvement in negative symptoms, cognition, and quality of life in schizophrenia patients. However, the biological mechanism/s of action of yoga in schizophrenia are not clear. The current study was aimed at exploring the effects of long-term (6 months) add-on yoga therapy on the immune inflammatory pathway in schizophrenia patients.

METHODS

Sixty schizophrenia patients were randomized to add-on yoga therapy (YT=30) and treatment-as-usual (TAU=30) groups of which 21 patients in YT and 20 in TAU group completed the study. Blood samples and clinical assessments were obtained at baseline and at the end of 6 months. The plasma levels of nine cytokines (IL-2, IL-4, IL-5, IL-10, IL-12(p70), IL-13, GM-CSF, IFN-γ, and TNF-α) were quantified using multiplex suspension array. The clinical assessments included SAPS, SANS, BPRS, PSS, CGI, SOFS and WHOQUOL-BREF.

RESULTS

Patients in the yoga group showed significant reductions in plasma TNF-α (Z = 2.99, p = 0.003) and IL-5 levels (Z = 2.20, p = 0.03) and greater clinical improvements in SAPS, SANS, PSS, and SOFS scores as compared to TAU group. Further, plasma TNF-α levels exhibited a positive correlation with negative symptoms (r_s =0.45, p = 0.02) and socio-occupational functioning (r_s =0.61, p = 0.002) in the YT group.

CONCLUSIONS

The findings of the study suggest that improvements in schizophrenia psychopathology with yoga interventions are associated with immuno-modulatory effects.

Acute IL-6 exposure triggers canonical IL6Ra signaling in hiPSC microglia, but not neural progenitor cells

BACKGROUND

Prenatal exposure to elevated interleukin (IL)-6 levels is associated with increased risk for psychiatric disorders with a putative neurodevelopmental origin, such as schizophrenia (SZ), autism spectrum condition (ASC) and bipolar disorder (BD). Although rodent models provide causal evidence for this association, we lack a detailed understanding of the cellular and molecular mechanisms in human model systems. To close this gap, we characterized the response of human induced pluripotent stem cell (hiPSC-)derived microglia-like cells (MGL) and neural progenitor cells (NPCs) to IL-6 in monoculture.

RESULTS

We observed that human forebrain NPCs did not respond to acute IL-6 exposure in monoculture at both protein and transcript levels due to the absence of IL6R expression and soluble (s)IL6Ra secretion. By contrast, acute IL-6 exposure resulted in STAT3 phosphorylation and increased IL6, JMJD3 and IL10 expression in MGL, confirming activation of canonical IL6Ra signaling. Bulk RNAseq identified 156 up-regulated genes (FDR < 0.05) in MGL following acute IL-6 exposure, including IRF8, REL, HSPA1A/B and OXTR, which significantly overlapped with an up-regulated gene set from human post-mortem brain tissue from individuals with schizophrenia. Acute IL-6 stimulation significantly increased MGL motility, consistent with gene ontology pathways highlighted from the RNAseq data and replicating rodent model indications that IRF8 regulates microglial motility. Finally, IL-6 induces MGLs to secrete CCL1, CXCL1, MIP-1α/β, IL-8, IL-13, IL-16, IL-18, MIF and Serpin-E1 after 3 h and 24 h.

CONCLUSION

Our data provide evidence for cell specific effects of acute IL-6 exposure in a human model system, ultimately suggesting that microglia-NPC co-culture models are required to study how IL-6 influences human cortical neural progenitor cell development in vitro.

Alteration patterns of peripheral concentrations of cytokines and associated inflammatory proteins in acute and chronic stages of schizophrenia: a systematic review and network meta-analysis

BACKGROUND

Immune system dysfunction is considered to play an aetiological role in schizophrenia spectrum disorders, with substantial alterations in the concentrations of specific peripheral inflammatory proteins, such as cytokines. However, there are inconsistencies in the literature over which inflammatory proteins are altered throughout the course of illness. Through conducting a systematic review and network meta-analysis, this study aimed to investigate the patterns of alteration that peripheral inflammatory proteins undergo in both acute and chronic stages of schizophrenia spectrum disorders, relative to a healthy control population.

METHODS

In this systematic review and meta-analysis, we searched PubMed, PsycINFO, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials from inception to March 31, 2022, for published studies reporting peripheral inflammatory protein concentrations in cases of people with schizophrenia-spectrum disorders and healthy controls. Inclusion criteria were: (1) observational or experimental design; (2) a population consisting of adults diagnosed with schizophrenia-spectrum disorders with a specified indicator of acute or chronic stage of illness; (3) a comparable healthy control population without mental illness; (4) a study outcome measuring the peripheral protein concentration of a cytokine, associated inflammatory marker, or C-reactive protein. We excluded studies that did not measure cytokine proteins or associated biomarkers in blood. Mean and SDs of inflammatory marker concentrations were extracted directly from full-text publshed articles; articles that did not report data as results or supplementary results were excluded (ie, authors were not contacted) and grey literature and unpublished studies were not sought. Pairwise and network meta-analyses were done to measure the standardised mean difference in peripheral protein concentrations between three groups: individuals with acute schizophrenia-spectrum disorder, individuals with chronic schizophrenia-spectrum disorder, and healthy controls. This protocol was registered on PROSPERO, CRD42022320305.

FINDINGS

Of 13 617 records identified in the database searches, 4492 duplicates were removed, 9125 were screened for eligibility, 8560 were excluded after title and abstract screening, and three were excluded due to limited access to the full-text article. 324 full-text articles were then excluded due to inappropriate outcomes, mixed or undefined schizophrenia cohorts, or duplicate study populations, five were removed due to concerns over data integrity, and 215 studies were included in the meta-analysis. 24 921 participants were included, with 13 952 adult cases of schizophrenia-spectrum disorder and 10 969 adult healthy controls (descriptive data for the entire cohort were not available for age, numbers of males and females, and ethnicity). Concentration of interleukin (IL)-1β, IL-1 receptor antagonist (IL-1RA), soluble interleukin-2 receptor (sIL-2R), IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, and C-reactive protein were consistently elevated in both individuals with acute schizophrenia-spectrum disorder and chronic schizophrenia-spectrum disorder, relative to healthy controls. IL-2 and interferon (IFN)-γ were significantly elevated in acute schizophrenia-spectrum disorder, while IL-4, IL-12, and IFN-γ were significantly decreased in chronic schizophrenia-spectrum disorder. Sensitivity and meta-regression analyses revealed that study quality and a majority of the evaluated methodological, demographic, and diagnostic factors had no significant impact on the observed results for most of the inflammatory markers. Specific exceptions to this included: methodological factors of assay source (for IL-2 and IL-8), assay validity (for IL-1β), and study quality (for transforming growth factor-β1); demographic factors of age (for IFN-γ, IL-4, and IL-12), sex (for IFN-γ and IL-12), smoking (for IL-4), and BMI (for IL-4); and diagnostic factors including diagnostic composition of schizophrenia-spectrum cohort (for IL-1β IL-2, IL-6, and TNF-α), antipsychotic-free cases (for IL-4 and IL-1RA), illness duration (for IL-4), symptom severity (for IL-4), and subgroup composition (for IL-4).

INTERPRETATION

Results suggest that people with schizophrenia-spectrum disorders have a baseline level of inflammatory protein alteration throughout the illness, as reflected by consistently elevated pro-inflammatory proteins, hypothesised here as trait markers (eg, IL-6), while those with acute psychotic illness might have superimposed immune activity with increased concentrations of hypothesised state markers (eg, IFN-γ). Further research is required to determine whether these peripheral alterations are reflected within the central nervous system. This research facilitates an entry point in understanding how clinically relevant inflammatory biomarkers might one day be useful to the diagnosis and prognostication of schizophrenia-spectrum disorders.

FUNDING

None.

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

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

The Inflammatory Signals Associated with Psychosis: Impact of Comorbid Drug Abuse

Psychosis and substance use disorders are two diagnostic categories whose association has been studied for decades. In addition, both psychosis spectrum disorders and drug abuse have recently been linked to multiple pro-inflammatory changes in the central nervous system. We have carried out a narrative review of the literature through a holistic approach. We used PubMed as our search engine. We included in the review all relevant studies looking at pro-inflammatory changes in psychotic disorders and substance use disorders. We found that there are multiple studies that relate various pro-inflammatory lipids and proteins with psychosis and substance use disorders, with an overlap between the two. The main findings involve inflammatory mediators such as cytokines, chemokines, endocannabinoids, eicosanoids, lysophospholipds and/or bacterial products. Many of these findings are present in different phases of psychosis and in substance use disorders such as cannabis, cocaine, methamphetamines, alcohol and nicotine. Psychosis and substance use disorders may have a common origin in an abnormal neurodevelopment caused, among other factors, by a neuroinflammatory process. A possible convergent pathway is that which interrelates the transcriptional factors NFκB and PPARγ. This may have future clinical implications.

Rituximab as an adjunctive treatment for schizophrenia spectrum disorder or obsessive-compulsive disorder: Two open-label pilot studies on treatment-resistant patients

In this explorative study, we investigated if an adjunctive treatment with one single dose of the monoclonal antibody rituximab would improve symptoms and function in treatment-resistant patients with schizophrenia spectrum disorder (SSD, n = 9) or obsessive-compulsive disorder (OCD, n = 10), based on the inflammatory hypothesis for mental disorders. Patients were followed for one year. Disability was measured with the Personal and Social Performance score (PSP). At baseline, the mean PANSS score in the SSD group was 99 ± 32 and the mean Y-BOCS score in the OCD group was 27.5 ± 7. Mean PSP scores were 32 ± 10.2 and 42.5 ± 9.9 in the SSD and OCD groups, respectively. Seven had Paediatric Acute-Onset Neuropsychiatric Syndrome (PANS) in retrospect, and 3 SSD patients had schizo-obsessive subtype. 4/8 SSD patients showed a ≥40% reduction in PANSS at endpoint I week 20, however, 7/9 were similarly improved already at week 12. Among the OCD patients, 2/10 showed a ≥35% reduction in Y-BOCS at week 20. Disability was significantly improved only in the SSD group. The percentual decrease of PANSS scores in SSD patients was associated with the increase in immunoglobulin levels week 20 (n = 8: IgG r = 0.85, p = .007; IgA r = 0.79, p = .019; IgM r = 0.73, p = .038). Rituximab was generally well tolerated in these patients. Self-rated improvements since baseline were reported for psychic (p = .021), neurological (p = .059), and autonomic (p < .001) side effects (UKU-SERS-Pat side-effect scale). Anxiety was commonly reported by OCD patients, while an initial increase in psychotic symptoms was seen in a few SSD patients. An RCT is underway to evaluate rituximab in SSD.

Chemokine Dysregulation and Neuroinflammation in Schizophrenia: A Systematic Review

Chemokines are known to be immunoregulatory proteins involved not only in lymphocyte chemotaxis to the site of inflammation, but also in neuromodulation, neurogenesis, and neurotransmission. Multiple lines of evidence suggest a peripheral proinflammatory state and neuroinflammation in at least a third of patients with schizophrenia. Therefore, chemokines can be active players in these processes. In this systematic review, we analyzed the available data on chemokine dysregulation in schizophrenia and the association of chemokines with neuroinflammation. It has been shown that there is a genetic association of chemokine and chemokine receptor gene polymorphisms in schizophrenia. Besides, the most reliable data confirmed by the results of meta-analyses showed an increase in CXCL8/IL-8, CCL2/MCP-1, CCL4/MIP-1β, CCL11/eotaxin-1 in the blood of patients with schizophrenia. An increase in CXCL8 has been found in cerebrospinal fluid, but other chemokines have been less well studied. Increased/decreased expression of genes of chemokine and their receptors have been found in different areas of the brain and peripheral immune cells. The peripheral proinflammatory state may influence the expression of chemokines since their expression is regulated by pro- and anti-inflammatory cytokines. Mouse models have shown an association of schizophrenia with dysregulation of the CX3CL1-CX3CR1 and CXCL12-CXCR4 axes. Altogether, dysregulation in chemokine expression may contribute to neuroinflammation in schizophrenia. In conclusion, this evidence indicates the involvement of chemokines in the neurobiological processes associated with schizophrenia.

Serum Inflammatory Markers and Integrity of the Superior Longitudinal Fasciculus and the Inferior Longitudinal Fasciculus in Schizophrenia, from Prodromal Stages to Chronic Psychosis-A Cross-Sectional Study

Chronic subclinical inflammation is believed to be an important factor in the pathogenesis of schizophrenia. Meta-analyses confirm the presence of increased levels of peripheral inflammatory markers (IM) in schizophrenia and its prodromal stages. Peripheral cytokines may affect the brain microstructure through chronic activation of microglia. Disruptions in the integrity of the superior longitudinal fasciculus (SLF) and inferior longitudinal fasciculus (ILF) are commonly seen in patients with schizophrenia spectrum disorders. We therefore attempted to verify in a cross-sectional study whether there is a correlation between levels of peripheral IM and the integrity of these brain regions in healthy controls, from prodromal states and first episode psychosis to long-term schizophrenia. The integrity of white matter was measured using diffusion tensor imaging. Despite a broad analysis of six IM (CRP, IL-6, IL-8, IL-10, TNF-α, and IFN-γ), we did not find any correlations with the integrity of the SLF or ILF in any of the analyzed groups (after correction for multiple comparisons). In conclusion, our study does not support the existence of a link between disrupted levels of peripheral IM and reduced integrity of ILF and SLF in schizophrenia spectrum disorders. However, prospective studies are needed to verify this over a long period of time.

[Features of inflammatory reactions in patients with juvenile depression with a clinically high risk of psychosis]

OBJECTIVE

To determine the levels of pro-inflammatory and anti-inflammatory cytokines and inflammatory markers such as C-reactive protein, leukocyte elastase, α1-proteinase inhibitor, autoantibodies to neuroantigens in the blood of patients with adolescent depression with clinical high risk for psychosis (CHR-P) and to study the relation of these biological markers to the features of psychopathological symptomatology of the patients.

MATERIAL AND METHODS

Eighty young adults, aged 16-24 years, with the first depressive episode (F32.1-2, F32.38, F32.8) were studied. Based on the presence of attenuated positive symptoms in the structure of depression, all patients were divided into two groups: with CHR-P (clinical group, n=58) and without CHR-P (comparative group, n=22). The HDRS-21, SOPS, and SANS were used for psychometric assessment of the patients. Serum levels of cytokines TNF-α, IL-6, IL-8, IL-10, and concentration of C-reactive protein (CRP) were determined. Leukocyte elastase (LE) activity, α1-proteinase inhibitor (α1-PI) activity, and plasma levels of autoantibodies to S100B protein and myelin basic protein (MBP) were assessed.

RESULTS

Both groups of patients were characterized by the high levels of inflammation as assessed by LE (250.5 (226.2-280.8) nmol/min·ml vs 248.3 (226.8-284.5) nmol/min·ml) and α1-PI activity (44.4 (37.5-50.1) IE/ml vs 45.2 (36.4-49.9) IE/ml). Higher levels (p<0.05) of IL-6 (1.22 (0.64-2.2) pg/ml), CRP (0.93 (0.18-3.18) mg/l), and TNF-α/IL-10 (0.34 (0.2-0.47)) were detected in the group with CHR-P. This group was also characterized by higher levels of antibodies to the S100B protein 0.78 (0.69-0.84 units of opt.density) compared with the group without CRH-P (p<0.05). In each clinical group, different correlations between clinical, psychometric and biological parameters were revealed.

CONCLUSIONS

The results confirm the involvement of inflammation in the development of depression in youth and indicate a different role of the inflammatory markers analyzed in the formation of CHR-P. The differences in the spectrum of inflammatory markers in depressed patients suggest a more pronounced pro-inflammatory potential in the group with CHR-P.

Potential Benefits of Anthocyanins in Chronic Disorders of the Central Nervous System

Anthocyanins have been shown to be effective in chronic diseases because of their antioxidant and anti-inflammatory effects together with changes in the gut microbiota and modulation of neuropeptides such as insulin-like growth factor-1. This review will examine whether these mechanisms may be effective to moderate the symptoms of disorders of the central nervous system in humans, including schizophrenia, Parkinson's disease, Alzheimer's disease, autism spectrum disorder, depression, anxiety, attention-deficit hyperactivity disorder and epilepsy. Thus, anthocyanins from fruits and berries should be considered as complementary interventions to improve these chronic disorders.

Cytokines as Potential Biomarkers of Clinical Characteristics of Schizophrenia

Immune activation plays a major role in the pathogenesis of schizophrenia, as confirmed by many studies, systematic reviews, and meta-analyses. The important role of neuroinflammation in the formation of the relation between impaired neurobiological processes and schizophrenia psychopathology is being actively discussed. We quantified serum concentrations of 22 cytokines in 236 patients with schizophrenia and 103 mentally and somatically healthy individuals by a multiplex assay. We found higher TGF-α (p = 0.014), IFN-γ (p = 0.036), IL-5 (p < 0.001), IL-6 (p = 0.047), IL-8 (p = 0.005), IL-10 (p <0.001), IL-15 (p = 0.007), IL-1RA (p = 0.007), and TNF-α (p < 0.001) levels in patients with schizophrenia than in healthy individuals. Subgroup analysis revealed a much greater number of statistically significant differences in cytokine levels among females than among males. Patients with a continuous course of schizophrenia showed statistically significantly higher levels of IL-12p70 (p = 0.019), IL-1α (p = 0.046), and IL-1β (p = 0.035) compared with patients with an episodic course. Most cytokines were positively correlated with positive, general, and total PANSS scores. In patients with a duration of schizophrenia of 10 years or more, the level of IL-10 was higher than that in patients with a disease duration of 5 years or less (p = 0.042). Thus, an imbalance in cytokines was revealed in patients with schizophrenia, depending on sex and clinical characteristics of the disease.

Investigating the regulation of the unc-33 promoter by environmental stressors

Environmental factors such as prenatal stress are hypothesized to contribute to the development of schizophrenia. Lee and colleagues determined rats exposed to prenatal stress exhibited decreased levels of only one protein, DPYSL2, in their prefrontal cortex and hippocampus. DYPSL2, a protein seen to be inactivated in schizophrenic patients, is important for neuronal development. The C. elegans homolog of DPYSL2, UNC-33, is also found to be critical for axonal outgrowth and synapse formation. Herein, we study the effects of environmental stressors such as increasing temperatures and pathogens on the expression of GFP driven by the unc-33 promoter. Results indicate that neuronal GFP expression was lower in C. elegans exposed to these prenatal stressors, making this the first report denoting an environmental regulation of the unc -33 promoter. This study provides insight into unc-33 and the regulation of its expression in relation to temperature and infection.

Cytokine Imbalance as a Biomarker of Treatment-Resistant Schizophrenia

Treatment-resistant schizophrenia (TRS) is an important and unresolved problem in biological and clinical psychiatry. Approximately 30% of cases of schizophrenia (Sch) are TRS, which may be due to the fact that some patients with TRS may suffer from pathogenetically “non-dopamine” Sch, in the development of which neuroinflammation is supposed to play an important role. The purpose of this narrative review is an attempt to summarize the data characterizing the patterns of production of pro-inflammatory and anti-inflammatory cytokines during the development of therapeutic resistance to APs and their pathogenetic and prognostic significance of cytokine imbalance as TRS biomarkers. This narrative review demonstrates that the problem of evaluating the contribution of pro-inflammatory and anti-inflammatory cytokines to maintaining or changing the cytokine balance can become a new key in unlocking the mystery of “non-dopamine” Sch and developing new therapeutic strategies for the treatment of TRS and psychosis in the setting of acute and chronic neuroinflammation. In addition, the inconsistency of the results of previous studies on the role of pro-inflammatory and anti-inflammatory cytokines indicates that the TRS biomarker, most likely, is not the serum level of one or more cytokines, but the cytokine balance. We have confirmed the hypothesis that cytokine imbalance is one of the most important TRS biomarkers. This hypothesis is partially supported by the variable response to immunomodulators in patients with TRS, which were prescribed without taking into account the cytokine balance of the relation between serum levels of the most important pro-inflammatory and anti-inflammatory cytokines for TRS.

Quetiapine Ameliorates MIA-Induced Impairment of Sensorimotor Gating: Focus on Neuron-Microglia Communication and the Inflammatory Response in the Frontal Cortex of Adult Offspring of Wistar Rats

The maternal immune activation produced by the systemic administration of lipopolysaccharide (LPS) in rats provides valuable insights into the basis of behavioural schizophrenia-like disturbances and biochemical changes in the brains of the offspring, such as microglial activation. Regarding therapy, antipsychotics continually constitute the cornerstone of schizophrenia treatment. To their various efficacy and side effects, as well as not fully recognised mechanisms of action, further characteristics have been suggested, including an anti-inflammatory action via the impact on neuron–microglia axes responsible for inhibition of microglial activation. Therefore, in the present study, we sought to determine whether chronic treatment with chlorpromazine, quetiapine or aripiprazole could influence schizophrenia-like behavioural disturbances at the level of sensorimotor gating in male offspring prenatally exposed to LPS. Simultaneously, we wanted to explore if the chosen antipsychotics display a positive impact on the neuroimmunological parameters in the brains of these adult animals with a special focus on the ligand-receptor axes controlling neuron–microglia communication as well as pro- and anti-inflammatory factors related to the microglial activity. The results of our research revealed the beneficial effect of quetiapine on deficits in sensorimotor gating observed in prenatally LPS-exposed offspring. In terms of axes controlling neuron–microglia communication and markers of microglial reactivity, we observed a subtle impact of quetiapine on hippocampal Cx3cl1 and Cx3cr1 levels, as well as cortical Cd68 expression. Hence, further research is required to fully define and explain the involvement of quetiapine and other antipsychotics in Cx3cl1-Cx3cr1 and/or Cd200-Cd200r axes modulation and inflammatory processes in the LPS-based model of schizophrenia-like disturbances.

Plasma linoelaidyl carnitine levels positively correlated with symptom improvement in olanzapine-treated first-episode drug-naïve schizophrenia

INTRODUCTION

Olanzapine (OLA) is one of the most commonly used second-generation antipsychotics for the treatment of schizophrenia. However, the heterogeneity of therapeutic response to OLA among schizophrenia patients deserves further exploration. The role of carnitine in the clinical response to OLA monotherapy remains unclear.

OBJECTIVES

The current study was designed to investigate whether carnitine and its derivatives are linked to the response to OLA treatment. Drug-naïve first-episode patients with schizophrenia were recruited and treated with OLA for 4 weeks. Psychiatric symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) in pre and post treatment.

RESULTS

After treatment, we found a significant decrease in 2-Octenoylcarnitine levels and a significant increase in linoelaidyl carnitine, 11Z-Octadecenylcarnitine and 9-Decenoylcarnitine levels. Furthermore, baseline linoelaidyl carnitine levels were correlated with the reduction of PANSS positive symptom subscore. Linear regression and logistic regression analyses found that the baseline linoelaidyl carnitine level was a predictive marker for the therapeutic response to OLA monotherapy for 4 weeks.

CONCLUSION

Our pilot study suggests that linoelaidyl carnitine levels at baseline may have a predictive role for the improvement of positive symptoms after OLA monotherapy in the patients with schizophrenia.

Increased blood-brain barrier permeability of the thalamus and the correlation with symptom severity and brain volume alterations in schizophrenia patients

BACKGROUND

Cumulative evidence of microvascular dysfunction has suggested the blood-brain barrier (BBB) disruption in schizophrenia, while the direct in vivo evidence from patients is inadequate. In this study, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) methods, we tried to test the hypothesis that there was increased BBB permeability in schizophrenia patients, and correlated with the clinical characters, and brain volumetric alterations.

METHODS

Structural MRI and DCE-MRI data from 29 schizophrenia patients and 18 age- and sex- matched controls (HC) were obtained. We calculated the volume transfer constant (K^trans) value and compared the difference between two groups. The regions with the abnormal K^trans value were extracted as ROIs (thalamus), and the correlation with the clinical characters and grey matter volume were analysed.

RESULTS

The results revealed that, compared with the HC, the volume transfer constant (K^trans) value of the bilateral thalamus in the schizophrenia group was increased (p < 0.001). There were significant positive correlations between thalamic mean K^trans value with disease duration (p < 0.05) and symptom severity (p < 0.001). Analysis of the thalamic subregions revealed that the BBB disruption was significant in pulvinar, especially the medial pulvinar nucleus (PuM) and lateral pulvinar nucleus (PuL) (p < 0.001). The K^trans value of the whole brain, thalamus, and thalamic subregions was negatively correlated with their volume separately.

CONCLUSION

These results provided the first in vivo evidence of BBB disruption of thalamus in schizophrenia patients, and the BBB dysfunction might contribute to the pathological brain structural alterations in schizophrenia.

Disrupted leptin-fatty acid biosynthesis is an early manifestation of metabolic abnormalities in schizophrenia

BACKGROUND

Insulin resistance (IR) and impaired energy expenditure (IEE) are irreparable metabolic comorbidities in schizophrenia. Although mechanism(s) underlying IR and IEE remains unclear, leptin and fatty acid signaling, which has profound influence on insulin secretion/sensitivity, glucose metabolism and energy expenditure, could be disrupted. However, no association of plasma leptin with erythrocyte membrane fatty acids, body mass index (BMI), and psychotic symptoms in the same cohort of untreated patients with first-episode psychosis (FEP) or medicated patients with chronic schizophrenia (CSZ) is presented before. These studies are crucial for deciphering the role of leptin and fatty acids in the development of IR and IEE in schizophrenia.

AIM

To determine the association between plasma leptin, erythrocyte membrane fatty acids, particularly, saturated fatty acids (SFAs), BMI and psychotic symptoms in patients with FEP and CSZ.

METHODS

In this study, twenty-two drug naive patients with FEP, twenty-one CSZ patients treated with atypical antipsychotic drugs, and fourteen healthy control (CNT) subjects were analyzed. Plasma leptin was measured using sandwich mode enzyme-linked immunosorbent assay. Erythrocyte membrane SFAs were measured using ultrathin capillary gas chromatography. BMI was calculated by using the formula: weight (kg)/height (m²). Psychiatric symptoms were evaluated at baseline using brief psychiatric rating scale (BPRS), and positive and negative syndrome scale (PANSS). The total BPRS scores, positive and negative symptom scores (PANSS-PSS and PANSS-NSS, respectively) were recorded. Pearson correlation coefficient (r) analyses were performed to find the nature and strength of association between plasma leptin, PANSS scores, BMI and SFAs, particularly, palmitic acid (PA).

RESULTS

In patients with FEP, plasma leptin not BMI was significantly lower (P = 0.034), whereas, erythrocyte membrane SFAs were significantly higher (P < 0.005) compared to the CNT subjects. Further, plasma leptin showed negative correlation with erythrocyte membrane SFAs-PA (r = −0.4972, P = 0.001), PANSS-PSS (r = −0.4034, P = 0.028), and PANSS-NSS (r = −0.3487, P = 0.048). However, erythrocyte membrane SFAs-PA showed positive correlation with PANSS-PSS (r = 0.5844, P = 0.0034) and PANSS-NSS (r = 0.5380, P = 0.008). In CSZ patients, plasma leptin, BMI, and erythrocyte membrane SFAs, all were significantly higher (P < 0.05) compared to the CNT subjects. Plasma leptin showed positive correlation with BMI (r = 0.312, P = 0.032) but not with PANSS scores or erythrocyte membrane SFAs-PA. However, erythrocyte membrane SFAs-PA showed positive correlation with PANSS-NSS only (r = 0.4729, P = 0.031). Similar changes in the plasma leptin and erythrocyte membrane SFAs have also been reported in individuals at ultra-high risk of developing psychosis; therefore, the above findings suggest that leptin-fatty acid biosynthesis could be disrupted before the onset of psychosis in schizophrenia.

CONCLUSION

Disrupted leptin-fatty acid biosynthesis/signaling could be an early manifestation of metabolic comorbidities in schizophrenia. Large-scale studies are warranted to validate the above findings.

Serum inflammatory markers and their associations with white matter integrity of the corpus callosum in schizophrenia patients and healthy controls

Schizophrenia is associated with disrupted integrity of white matter microstructure of a variety of brain regions, especially the corpus callosum (CC). Chronic subclinical inflammation is considered to be one of the factors involved in the pathogenesis of this disease, and increased levels of peripheral inflammatory markers are often observed in schizophrenia patients. Therefore, we decided to investigate whether the integrity of the corpus callosum is correlated with levels of these markers. A total of 50 patients with stable chronic schizophrenia (SCH) and 30 controls (CON) were enrolled in the study. All participants underwent psychiatric evaluation, neuroimaging, and blood sampling including the measurement of serum concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL - 10), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), and C-reactive protein (CRP). Additional potentially related factors, such as age, gender, BMI, smoking, disease duration, and treatment were included in the analysis. Significantly higher IL-6 and IFN-γ levels were observed in SCH compared to CON. In SCH, IFN-γ was positively correlated with mean diffusivity of region 2 of the CC. In CON, IL-6 was inversely correlated with fractional anisotropy of region 1 of the CC. These results support the potential influence of peripheral inflammatory markers on the integrity of the CC in schizophrenia, but require verification in longitudinal studies.

Schizophrenia and Alarmins

Schizophrenia, consisting of a group of severe psychiatric disorders with a complex etiology, is a leading cause of disability globally. Due to the lack of objective indicators, accurate diagnosis and selection of effective treatments for schizophrenia remain challenging. The association between schizophrenia and alarmins levels has been proposed for many years, but without solid evidence. Alarmins are prestored molecules that do not require processing and can be released upon cell death or damage, making them an ideal candidate for an early initiator of inflammation. Immunological biomarkers seem to be related to disease progression and treatment effectiveness. Several studies suggest strong associations among the high-mobility group box 1 protein (HMGB1), interleukin-1α, interleukin-33, S100B, heat-shock proteins, and uric acid with schizophrenic disorders. The purpose of this review is to discuss the evidence of central and peripheral immune findings in schizophrenia, their potential causes, and the effects of immunomodulatory therapies on symptoms and outline potential applications of these markers in managing the illness. Although there are currently no effective markers for diagnosing or predicting treatment effects in patients with schizophrenia, we believe that screening immune-inflammatory biomarkers that are closely related to the pathological mechanism of schizophrenia can be used for early clinical identification, diagnosis, and treatment of schizophrenia, which may lead to more effective treatment options for people with schizophrenia.

The mechanisms of interactions of psychotropic drugs with liver and brain cytochrome P450 and their significance for drug effect and drug-drug interactions

Cytochrome P450 (CYP) plays an important role in psychopharmacology. While liver CYP enzymes are responsible for the biotransformation of psychotropic drugs, brain CYP enzymes are involved in the local metabolism of these drugs and endogenous neuroactive substances, such as neurosteroids, and in alternative pathways of neurotransmitter biosynthesis including dopamine and serotonin. Recent studies have revealed a relation between the brain nervous system and cytochrome P450, indicating that CYP enzymes metabolize endogenous neuroactive substances in the brain, while the brain nervous system is engaged in the central neuroendocrine and neuroimmune regulation of cytochrome P450 in the liver. Therefore, the effect of neuroactive drugs on cytochrome P450 should be investigated not only in vitro, but also at in vivo conditions, since only in vivo all mechanisms of drug-enzyme interaction can be observed, including neuroendocrine and neuroimmune modulation. Psychotropic drugs can potentially affect cytochrome P450 via a number of mechanisms operating at the level of the nervous, hormonal and immune systems, and the liver. Their effect on cytochrome P450 in the brain is often different than in the liver and region-dependent. Since psychotropic drugs can affect cytochrome P450 both in the liver and brain, they can modify their own pharmacological effect at both pharmacokinetic and pharmacodynamic level. The article describes the mechanisms by which psychotropic drugs can change the expression/activity of cytochrome P450 in the liver and brain, and discusses the significance of those mechanisms for drug action and drug-drug interactions. Moreover, the brain CYP2D6 is considered as a potential target for psychotropics.

Psychopathology and Integrity of the Superior Longitudinal Fasciculus in Deficit and Nondeficit Schizophrenia

The superior longitudinal fasciculus (SLF) is a white matter bundle that connects the frontal areas with the parietal areas. As part of the visuospatial attentional network, it may be involved in the development of schizophrenia. Deficit syndrome (DS) is characterized by primary and enduring negative symptoms. The present study assessed SLF integrity in DS and nondeficit schizophrenia (NDS) patients and examined possible relationships between it and psychopathology. Twenty-six DS patients, 42 NDS patients, and 36 healthy controls (HC) underwent psychiatric evaluation and diffusion tensor imaging (DTI). After post-processing, fractional anisotropy (FA) values within the SLF were analyzed. Psychopathology was assessed with the Positive and Negative Syndrome Scale, Brief Negative Symptom Scale, and Self-evaluation of Negative Symptoms. The PANSS proxy for the deficit syndrome was used to diagnose DS. NDS patients had lower FA values than HC. DS patients had greater negative symptoms than NDS patients. After differentiating clinical groups and HC, we found no significant correlations between DTI measures and psychopathological dimensions. These results suggest that changes in SLF integrity are related to schizophrenia, and frontoparietal dysconnection plays a role in its etiopathogenesis. We confirmed that DS patients have greater negative psychopathology than NDS patients. These results are preliminary; further studies are needed.

Is There a Link between Oropharyngeal Microbiome and Schizophrenia? A Narrative Review

The study aimed to examine the impact of the oropharyngeal microbiome in the pathophysiology of schizophrenia and to clarify whether there might be a bidirectional link between the oral microbiota and the brain in a context of dysbiosis-related neuroinflammation. We selected nine articles including three systemic reviews with several articles from the same research team. Different themes emerged, which we grouped into 5 distinct parts concerning the oropharyngeal phageome, the oropharyngeal microbiome, the salivary microbiome and periodontal disease potentially associated with schizophrenia, and the impact of drugs on the microbiome and schizophrenia. We pointed out the presence of phageoma in patients suffering from schizophrenia and that periodontal disease reinforces the role of inflammation in the pathophysiology of schizophrenia. Moreover, saliva could be an interesting substrate to characterize the different stages of schizophrenia. However, the few studies we have on the subject are limited in scope, and some of them are the work of a single team. At this stage of knowledge, it is difficult to conclude on the existence of a bidirectional link between the brain and the oral microbiome. Future studies on the subject will clarify these questions that for the moment remain unresolved.

LncRNA colorectal neoplasia differentially expressed exacerbates the impairments in learning and memory induced by isoflurane

Background

This observation aimed to investigate the effect of colorectal neoplasia differentially expressed (CRNDE) targeted miR-212-5p on cognitive impairment induced by isoflurane (ISO) anesthesia in rats.

Methods

The cognitive function of rats was measured by Morris water maze test. QRT-PCR detection of CRNDE and miR-212-5p expression levels in rats in each group. Double luciferase was used to verify the targeting relationship between miR-212-5p and CRNDE, and commercial kits were used to detect the level of inflammatory cytokines in hippocampus.

Results

The concentration of CRNDE was enhanced in rats treated by ISO anesthetic. The neurological severity score was elevated, the escape latency of rats was prolonged, the stay time in the quadrant of the platform, and the number of times crossing the platform decreased in the ISO group. The above indexes of rats in ISO + si-CRNDE were improved. MiR-212-5p is a mediator in the management of CRNDE on cognition and inflammation.

Conclusion

CRNDE led to the deterioration of impairment on cognition induced by ISO through suppressing miR-212-5p expression and promoting neuroinflammation.

CNS pharmacology of NKCC1 inhibitors

The Na-K-2Cl cotransporter NKCC1 and the neuron-specific K-Cl cotransporter KCC2 are considered attractive CNS drug targets because altered neuronal chloride regulation and consequent effects on GABAergic signaling have been implicated in numerous CNS disorders. While KCC2 modulators are not yet clinically available, the loop diuretic bumetanide has been used off-label in attempts to treat brain disorders and as a tool for NKCC1 inhibition in preclinical models. Bumetanide is known to have anticonvulsant and neuroprotective effects under some pathophysiological conditions. However, as shown in several species from neonates to adults (mice, rats, dogs, and by extrapolation in humans), at the low clinical doses of bumetanide approved for diuresis, this drug has negligible access into the CNS, reaching levels that are much lower than what is needed to inhibit NKCC1 in cells within the brain parenchyma. Several drug discovery strategies have been initiated over the last ∼15 years to develop brain-permeant compounds that, ideally, should be selective for NKCC1 to eliminate the diuresis mediated by inhibition of renal NKCC2. The strategies employed to improve the pharmacokinetic and pharmacodynamic properties of NKCC1 blockers include evaluation of other clinically approved loop diuretics; development of lipophilic prodrugs of bumetanide; development of side-chain derivatives of bumetanide; and unbiased high-throughput screening approaches of drug discovery based on large chemical compound libraries. The main outcomes are that (1), non-acidic loop diuretics such as azosemide and torasemide may have advantages as NKCC1 inhibitors vs. bumetanide; (2), bumetanide prodrugs lead to significantly higher brain levels than the parent drug and have lower diuretic activity; (3), the novel bumetanide side-chain derivatives do not exhibit any functionally relevant improvement of CNS accessibility or NKCC1 selectivity vs. bumetanide; (4) novel compounds discovered by high-throughput screening may resolve some of the inherent problems of bumetanide, but as yet this has not been achieved. Thus, further research is needed to optimize the design of brain-permeant NKCC1 inhibitors. In parallel, a major challenge is to identify the mechanisms whereby various NKCC1-expressing cellular targets of these drugs within (e.g., neurons, oligodendrocytes or astrocytes) and outside the brain parenchyma (e.g., the blood-brain barrier, the choroid plexus, and the endocrine system), as well as molecular off-target effects, might contribute to their reported therapeutic and adverse effects.

Brain Fog: A Bit of Clarity Regarding Etiology, Prognosis, and Treatment

Brain fog is a lay term used to describe cognitive difficulties. Brain fog can be a response to lack of sleep, poor nutrition, medications, or drugs; however, the term is often used to describe the subjective experience of neuroinflammation. Chronic low-level inflammation is the most detrimental to the mind and body. The purpose of the current article is to examine the mechanisms, associated symptoms, and treatments for neuroinflammation and brain fog. The state of the science is lacking evidence for specific treatments targeting the mechanisms/pathways of neuroinflammation for precision-based care, yet there are pharmacological and nonpharmacological interventions that can reduce inflammation and improve functioning. [Journal of Psychosocial Nursing and Mental Health Services, 59(11), 9-13.].

First-Time Psychotic Symptoms in a Patient After COVID-19 Infection-A Case Report

A 39-year-old, previously healthy, white male with no personal or family history of mental illness presented with new, first-time psychotic symptoms. The new psychotic symptoms appeared on patient admission to the hospital, occurring during a diagnosis of symptomatic SARS-CoV-2 infection. On the first day of hospitalization for worsening psychotic symptoms and the appearance of aggression toward the staff, the patient was transferred to the psychiatric hospital. After the initial treatment with antipsychotics and benzodiazepines, his mental condition improved. The patient was then transferred for further treatment of his somatic condition in the internal medicine ward, with a recommendation to continue treatment in the psychiatric ward once his somatic condition was stabilized. This is one of the few reported cases of COVID-19-related psychosis in a patient without a personal or family history; moreover, this description contains important data regarding elevated IL-6, which may prove to be a key factor in the induction of new psychotic symptoms. It indicates the important need for careful monitoring of neuropsychiatric symptoms among COVID-19 patients.