Inflammation and immunity in schizophrenia: implications for pathophysiology and treatment

Schizophrenia is associated with altered DNA methylation variance

Varying combinations of genetic and environmental risk factors are thought to underpin phenotypic heterogeneity between individuals in psychiatric conditions such as schizophrenia. While epigenome-wide association studies in schizophrenia have identified extensive alteration of mean DNA methylation levels, less is known about the location and impact of DNA methylation variance, which could contribute to phenotypic and treatment response heterogeneity. To explore this question, we conducted the largest meta-analysis of blood DNA methylation variance in schizophrenia to date, leveraging three cohorts comprising 1036 individuals with schizophrenia and 954 non-psychiatric controls. Surprisingly, only a small proportion (0.1%) of the 213 variably methylated positions (VMPs) associated with schizophrenia (Benjamini-Hochberg FDR < 0.05) were shared with differentially methylated positions (DMPs; sites with mean changes between cases and controls). These blood-derived VMPs were found to be overrepresented in genes previously associated with schizophrenia and amongst brain-enriched genes, with evidence of concordant changes at VMPs in the cerebellum, hippocampus, prefrontal cortex, or striatum. Epigenetic covariance was also observed with respect to clinically significant metrics including age of onset, cognitive deficits, and symptom severity. We also uncovered a significant VMP in individuals with first-episode psychosis (n = 644) from additional cohorts and a non-psychiatric comparison group (n = 633). Collectively, these findings suggest schizophrenia is associated with significant changes in DNA methylation variance, which may contribute to individual-to-individual heterogeneity.

Targeting the gut microbiota-inflammation-brain axis as a potential therapeutic strategy for psychiatric disorders: A Mendelian randomization analysis

BACKGROUND

Extensive research indicates a link between gut microbiota dysbiosis and psychiatric disorders. However, the causal relationships between gut microbiota and different types of psychiatric disorders, as well as whether inflammatory factors mediate these relationships, remain unclear.

METHODS

We utilized summary statistics from the largest genome-wide association studies to date for gut microbiota (n = 18,340 in MiBioGen consortium), circulating inflammatory factors (n = 8293 for 41 factors and n = 14,824 for 91 factors in GWAS catalog), and six major psychiatric disorders from the Psychiatric Genomics Consortium (PGC): attention deficit hyperactivity disorder (ADHD, n = 38,691), anxiety disorder (ANX, n = 2248), bipolar disorder (BIP, n = 41,917), anorexia nervosa (AN, n = 16,992), schizophrenia (SCZ, n = 36,989), and autism spectrum disorder (ASD, n = 18,381). We conducted bidirectional Mendelian randomization (MR) analysis to explore the causal relationships between gut microbiota and psychiatric disorders. Additionally, we performed two-step MR and multivariable MR (MVMR) analyses to identify potential mediating inflammatory factors.

RESULTS

We found significant causal relationships between 11 gut microbiota and ADHD, 2 gut microbiota and ANX, 11 gut microbiota and BIP, 8 gut microbiota and AN, 15 gut microbiota and SCZ, and 5 gut microbiota and ASD. There were 16 positive and 15 negative causal effects between inflammatory factors and psychiatric disorders. Furthermore, MVMR analysis results indicated that the correlation between genus Roseburia and ADHD was mediated by MCSF, with a mediation proportion of 3.3 %; the correlation between genus Erysipelotrichaceae UCG003 and BIP was mediated by GDNF, with a mediation proportion of 3.7 %; and the correlation between family Prevotellaceae and SCZ was mediated by CD40, with a mediation proportion of 8.2 %.

CONCLUSIONS

The MR analysis results supported causal relationships between gut microbiota and six psychiatric disorders, as well as the potential mediating role of inflammatory factors. This study highlights the potential role of the gut microbiota-inflammation-brain axis in psychiatric disorders.

Monocytic TLR4 expression and activation in schizophrenia: A systematic review and meta-analysis

BACKGROUND

The role of toll-like receptor 4 (TLR4) in schizophrenia remains unclear, with studies reporting conflicting results on its expression and activation in persons with schizophrenia (PwSCZ). This systematic review/meta-analysis compared basal monocytic TLR4 expression, as well as its activation pattern between PwSCZ and healthy controls (HCs).

METHODS

This study was registered with PROSPERO (CRD42021273858) and adhered to the PRISMA guidelines. A systematic search was conducted through MEDLINE (via PubMed), Web of Science, and Scopus from inception to December 12, 2023. Quantitative syntheses were conducted for (a) basal monocytic TLR4 density, (b) basal percentage of TLR4+ monocytes, and (c) basal TLR4 gene expression. Effect sizes were computed using Hedges' g for mean differences. Random-effect models with restricted maximum-likelihood estimation were used, and subgrouping was conducted based on antipsychotic status. The studies' risk of bias was assessed using the Joanna Briggs Institute (JBI) tool.

RESULTS

Eleven studies (473 PwSCZ, 416 HCs) were included. Pooled analysis revealed a nonsignificant trend toward increased basal monocytic TLR4 density in PwSCZ (Hedges' g = 0.317 [95% CI: -0.060, 0.694], τ2 = 0.127, I2 = 68.91%). The difference became significant after sensitivity analysis and excluding one study (Hedges' g = 0.469 [0.195,0.742], p = 0.001). No significant difference was found between the groups in terms of TLR4+ monocytes percentage (Hedges' g = 0.235 [-0.245, 0.715], τ2 = 0.31, I2 = 87.30%) or TLR4 gene expression (Hedges' g = 0.179 [-0.502, 0.861], τ2 = 0.29, I2 = 79.04%). According to qualitative synthesis, TLR4 stimulation resulted in reduced monocytic activation in PwSCZ compared to HCs.

CONCLUSIONS

This study suggested a trend toward an increased basal monocytic TLR4 density in PwSCZ, with no difference in the basal percentage of TLR4+ monocytes or TLR4 gene expression. However, the limited available data underscores the need for future studies.

The anti-inflammation pharmacodynamics of lithium: Therapy of bipolar disorder

Bipolar disorder is a severe mental disorder that necessitates effective long-term treatment strategies. Clinically, lithium has demonstrated favorable outcomes in managing this condition. The inflammatory theory posits that bipolar disorder is influenced by an inflammatory response, and lithium is thought to mitigate this disorder by inhibiting such responses. In terms of the pharmacodynamics of blocking inflammatory mediators, lithium mainly acts on GSK-3β. Upon interaction with GSK-3β, lithium can suppress the gene expression of inflammatory mediators, subsequently reducing their secretion. This mechanism influences multiple downstream pathways, ultimately contributing to the therapeutic effects observed in bipolar disorder. Specifically, these pathways include the arachidonic acid pathway, nitric oxide synthase pathway, neurotransmitter pathway, and so on. This article reviews the pharmacodynamic targets and mechanisms of lithium, offering insights into the appropriate clinical application of lithium and the advancement of lithium pharmacotherapies.

Urolithin A alleviates schizophrenic-like behaviors and cognitive impairment in rats through modulation of neuroinflammation, neurogenesis, and synaptic plasticity

Cognitive impairment in schizophrenia occurs in the early stages of the disease and is closely associated with prognosis. Alleviation of cognitive impairment in schizophrenia faces major challenges owing to the lack of preventive and therapeutic drugs that are novel and effective. Urolithin A (UA) is a gut microbial metabolite of ellagic acid that has demonstrated neuroprotective effects in multiple neurological disease models. Nonetheless, the neuromodulatory role of UA in schizophrenia is yet to be elucidated. Wistar rat pups were separated from their mothers for 24 h on postnatal days (PNDs) 9-10 to establish an early-life stress model. The pups were pretreated with UA at different administration times (2, 4, and 6 weeks) and doses (50, 100, and 150 mg/kg) from adolescence (PND29). Behavioral tests were performed after the end of the administration. Subsequently, hippocampal samples were collected for histopathological and molecular evaluations. Male offspring rats subjected to maternal separation exhibited increased sensitivity to prepulse inhibition and cognitive impairment, accompanied by severe neuroinflammation and impaired neurogenesis. However, UA attenuated maternal separation-induced prepulse inhibition deficits and cognitive impairments and restored hippocampal neurogenesis in a dose-dependent manner. Furthermore, UA pretreatment preserved dendritic spine density, synapses, and presynaptic vesicles. In addition, it exerted anti-inflammatory effects by inhibiting microglial activation and expression of the proinflammatory cytokines tumor necrosis factor-α, interleukin-6, and interleukin-1β. Potential mechanisms included upregulation of brain-derived neurotrophic factor protein expression and activation of the extracellular signal-regulated kinase signaling pathway. This study is the first preclinical evaluation of the effects of UA on cognitive impairment in schizophrenia. The findings suggest that changes in cognitive function linked to schizophrenia are driven by the interaction among neuroinflammation, neurogenesis, and synaptic plasticity and that UA has the potential to reverse these processes. These observations provide evidence for future clinical trials of UA as a dietary supplement for preventing schizophrenia.

Kynurenine amplifies tetrahydrocannabinol-induced sensorimotor impairment and classic "tetrad" effects in mice

BACKGROUND

L-kynurenine (KYN), a kynurenine pathway (KP) metabolite, is the main precursor for the neuroactive metabolite kynurenic acid (KYNA). Several studies suggest a patho-physiologically relevant association between increased brain KYNA levels and cognitive dysfunctions in individuals with schizophrenia. Δ9-tetrahydrocannabinol (Δ9-THC; i.e. the main psychoactive compound of cannabis) can worse schizophrenia-related psychosis, often leads to the development of cannabis use disorder in individuals with schizophrenia, and increases the risk of earlier onset of schizophrenia symptoms in those with a genetic predisposition. A role of KP alterations and, specifically, increased brain KYNA levels in Δ9-THC-induced psychotic symptoms has been previously proposed. The aim of the study was to investigate on the possible involvement of KP alterations in Δ9-THC-induced sensorimotor and "tetrad" responses in mice.

METHODS

Adult male CD-1 mice were treated with Δ9-THC (30 mg/ kg; i.p.) and KYN (20 mg/kg; i.p.), alone or in combination, and body temperature, acute mechanical and thermal analgesia, motor activity and sensorimotor responses were evaluated. Furthermore, brain KYNA levels as well as plasma Δ9-THC and its metabolites concentrations after the treatments were also evaluated.

RESULTS

Brain KYNA levels were significantly increased 1 h, but not 4 h, after KYN and KYN + Δ9-THC administration. KYN administration amplified the Δ9-THC-induced impairment of sensorimotor responses (visual placing, acoustic and tactile responses). Furthermore, KYN significantly increased Δ9-THC-induced motor activity impairment (bar test, drag test and rotarod test) and hypothermia (core and surface body temperature), but not Δ9-THC-induced analgesia. Finally, 1 h after Δ9-THC administration, Δ9-THC and its psychoactive metabolite 11-OH-THC plasma levels were higher in mice pretreated with KYN than in control mice.

CONCLUSIONS

The present data indicate for the first time that KYN amplifies the THC-induced sensorimotor impairment and classic "tetrad" response possibly through a pharmacokinetic interaction.

Psychiatric morbidity in people with autoimmune arthritides as a model of inflammatory mechanisms in mental disorders

BACKGROUND

Rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA) are autoimmune illnesses characterised by chronic inflammation demonstrating differential associations with psychiatric conditions.

OBJECTIVE

In this matched-cohort study, we aimed to investigate whether the associations between these inflammatory illnesses and mental disorders are predominantly the consequence of the burden of the former or whether common causes might underpin the susceptibility to both.

METHODS

Using Czech national inpatient care data, we identified individuals with RA or axSpA during the years 1999-2012. We investigated the occurrence of psychiatric outcomes up to 2017 using stratified Cox proportional hazards models. In evidence triangulation, we assessed the potential moderation by age at inflammatory illness, the associations relative to counterparts with other similarly burdensome chronic illnesses and the temporal ordering of conditions.

FINDINGS

Both RA and axSpA were associated with mood and anxiety disorders and behavioural syndromes. In evidence triangulation, the associations with depression showed a decreasing age-at-inflammatory-illness gradient in RA; the association between RA and depression was stronger than that between other chronic illnesses and depression; and excluding prevalent depression attenuated the RA-depression association. RA showed consistent inverse associations with schizophrenia and Alzheimer's disease.

CONCLUSIONS

Common aetiologies might be involved in increasing the risk of developing both RA and depression. The consistent inverse associations between RA and schizophrenia and between RA and Alzheimer's disease suggest that at least part of these associations might also be a consequence of shared aetiologies as well as potential medication effects.

CLINICAL IMPLICATIONS

People with autoimmune arthritides are more likely to experience mood and anxiety disorders, even relative to counterparts with other similarly burdensome chronic illnesses.

Association between autoimmune disease and neurodevelopmental disorder: a Mendelian randomization analysis

INTRODUCTION

Neurodevelopmental disorders such as attention deficit and disruptive behaviour disorders (ADHD), autism spectrum disorder (ASD), and schizophrenia have been increasingly prevalent recently. Previous research has demonstrated that inflammatory activity from autoimmune diseases is involved in neurological diseases. However, some studies question the association between inflammatory activities and neurodevelopmental disorders. Herein, we attempt to clarify this relationship using Mendelian randomization (MR) analysis.

METHODS

We used systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 1 diabetes mellitus (T1D) to represent autoimmune diseases. First, we conducted MR analysis to examine associated SNPs between autoimmune and neurodevelopmental disorders. Second, we performed bidirectional MR analysis to identify 429 types of signalling peptides and proteins or relevant receptors with causality reported diseases. Finally, we compared the genes with the gene loci identified in the available TWAS-hub site.

RESULTS

The MR results of autoimmune diseases on neurodevelopmental disorders did not present any significant association in all models. However, we identified 20-45 factors in ADHD, ASD, and schizophrenia, including semaphorin 3, IL-27 receptor subunit alpha, and fibroblast growth factor 16, which were considered clinically significant pro-inflammatory mediators. GO and KEGG enrichment analyses revealed unequal integrities among the three neurodevelopmental diseases, and we failed to identify a shared pathway linking autoimmune diseases and neurodevelopmental disorders. TWAS analysis indicated that CHRNA5 potentially mediates inflammatory activities in schizophrenia.

CONCLUSION

According to our data, we failed to identify an association between autoimmune diseases and neurodevelopmental disorders. However, we demonstrated that some pro-inflammatory factors are involved in neurodevelopmental disorders.

Deconstruct the link between gut microbiota and neurological diseases: application of Mendelian randomization analysis

Background

Recent research on the gut-brain axis has deepened our understanding of the correlation between gut bacteria and the neurological system. The inflammatory response triggered by gut microbiota may be associated with neurodegenerative diseases. Additionally, the impact of gut microbiota on emotional state, known as the "Gut-mood" relationship, could play a role in depression and anxiety disorders.

Results

This review summarizes recent data on the role of gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including epilepsy, schizophrenia, Alzheimer's disease, brain cancer, Parkinson's disease, bipolar disorder and stroke. Also, we conducted a Mendelian randomization study on seven neurological disorders (Epilepsy, schizophrenia, Alzheimer's disease, brain cancer, Parkinson's disease, bipolar disorder and stroke). MR-Egger and MR-PRESSO tests confirmed the robustness of analysis against horizontal pleiotropy.

Conclusions

By comparing the protective and risk factors for neurological disorders found in our research and other researches, we can furtherly determine valuable indicators for disease evolution tracking and potential treatment targets. Future research should explore extensive microbiome genome-wide association study datasets using metagenomics sequencing techniques to deepen our understanding of connections and causality between neurological disorders.

Morphological alterations of the thymus gland in individuals with schizophrenia

Despite its critical function in the immune system and accumulating evidence of immunological abnormalities in schizophrenia, the thymus has long been overlooked. We aimed to investigate thymic morphological alterations and their corresponding heterogeneity in patients with schizophrenia. Imaging-derived thymic morphology was assessed and compared between 419 patients with schizophrenia and 460 age- and sex-matched control participants aged 16-40 years who underwent chest computed tomography (CT) scanning. These included measurements reflecting thymic size and density, such as average maximal thickness, anteroposterior distance, and average CT attenuation, which were also used to identify patient subtypes based on an unsupervised machine learning algorithm. Once the thymus-based patient subtypes were identified, between-subtype differences in the thymic and blood immunometabolic profiles were further tested. Case-control comparisons revealed that patients had greater average maximal thickness (Glass's delta [Δ] effect size = 0.37) but lower average CT attenuation (Δ = -0.18) in the thymus than controls. Two thymus-based subtypes with disparate thymic and blood immunometabolic profiles were identified. Specifically, Subtype 1 (containing 40.1% of patients) was characterized as greater average maximal thickness (Δ = 1.36) and longer anteroposterior distance (Δ = 0.71) but lower CT attenuation (Δ = -0.97), contrary to the abnormal patterns of Subtype 2. Furthermore, Subtype 1 had higher levels of blood immunometabolic profiles, such as lymphocyte count and lipid measures, than Subtype 2. Altered thymic morphology with considerable heterogeneity was first reported in schizophrenia, providing evidence for the immune hypothesis and facilitating the discovery of imaging biomarkers reflecting the immunometabolic status.

Maternal immune activation followed by peripubertal stress combinedly produce reactive microglia and confine cerebellar cognition

The functional alteration of microglia arises in brains exposed to external stress during early development. Pathophysiological findings of neurodevelopmental disorders such as schizophrenia and autism spectrum disorder suggest cerebellar functional deficits. However, the link between stress-induced microglia reactivity and cerebellar dysfunction is missing. Here, we investigate the developmental immune environment in translational mouse models that combine two risk factors: maternal infection and repeated social defeat stress (2HIT). We find the synergy of inflammatory stress insults, leading to microglial increase specifically in the cerebellum of both sexes. Microglial turnover correlates with the Purkinje neuron loss in 2HIT mice. Highly multiplexed imaging-mass-cytometry identifies a cell transition to TREM2(+) stress-associated microglia in the cerebellum. Single-cell-proteomic clustering reveals IL-6- and TGFβ-signaling association with microglial cell transitions. Reduced excitability of remaining Purkinje cells, cerebellum-involved brain-wide functional dysconnectivity, and behavioral abnormalities indicate cerebellar cognitive dysfunctions in 2HIT animals, which are ameliorated by both systemic and cerebellum-specific microglia replacement.

The Dysregulation of the Glymphatic System in Patients with Psychosis Spectrum Disorders Minimally Exposed to Antipsychotics: La dérégulation du système glymphatique en présence de troubles psychotiques chez des patients peu exposés à des antipsychotiques

OBJECTIVE

The pathophysiological mechanisms influencing psychosis spectrum disorders are largely unknown. The glymphatic system, which is a brain waste clearance pathway, has recently been implicated in its pathophysiology and has also been shown to be disrupted in various neurodegenerative and vascular diseases. Initial studies examining the glymphatic system in psychosis spectrum disorders have reported disruptions, but the findings have been confounded by medication effects as they included antipsychotic-treated patients. In this study, we used diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) as a technique to measure the functionality of the glymphatic system in a sample of antipsychotic-minimally exposed patients with psychosis spectrum disorders and healthy controls.

METHODS

The study included 13 antipsychotic-minimally exposed (2 weeks antipsychotic exposure in the past 3 months/lifetime) patients with psychosis spectrum disorders and 114 healthy controls. We quantified water diffusion metrics along the x-, y-, and z-axes in both projection and association fibres to derive the DTI-ALPS index, a proxy for glymphatic activity. Between-group differences were analyzed using two-way ANCOVA controlling for age and sex. Partial correlations were used to assess the association between the ALPS index and clinical variables.

RESULTS

Analyses revealed that antipsychotic-minimally exposed psychosis spectrum disorder patients had a lower DTI-ALPS index value than healthy controls in both hemispheres and the whole brain (all P < 0.005). Significant differences were also observed between the x and y projections/associations between patients and healthy controls (P < 0.001). Furthermore, we did not find any significant correlations (all P > 0.05) between the DTI-ALPS index with age, body mass index, symptomatology, and metabolic parameters.

CONCLUSION

This study shows that the glymphatic system is dysregulated in antipsychotic-minimally exposed patients with psychosis spectrum disorders. Understanding the mechanisms that influence the glymphatic system may help to understand the pathophysiology of psychosis spectrum disorders as proper waste clearance is needed for normal brain functioning.

Identification of Immune-Related Biomarkers of Schizophrenia in the Central Nervous System Using Bioinformatic Methods and Machine Learning Algorithms

Schizophrenia is a disastrous mental disorder. Identification of diagnostic biomarkers and therapeutic targets is of significant importance. In this study, five datasets of schizophrenia post-mortem prefrontal cortex samples were downloaded from the GEO database and then merged and de-batched for the analyses of differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA). The WGCNA analysis showed the six schizophrenia-related modules containing 12,888 genes. The functional enrichment analyses indicated that the DEGs were highly involved in immune-related processes and functions. The immune cell infiltration analysis with the CIBERSORT algorithm revealed 12 types of immune cells that were significantly different between schizophrenia subjects and controls. Additionally, by intersecting DEGs, WGCNA module genes, and an immune gene set obtained from online databases, 151 schizophrenia-associated immune-related genes were obtained. Moreover, machine learning algorithms including LASSO and Random Forest were employed to further screen out 17 signature genes, including GRIN1, P2RX7, CYBB, PTPN4, UBR4, LTF, THBS1, PLXNB3, PLXNB1, PI15, RNF213, CXCL11, IL7, ARHGAP10, TTR, TYROBP, and EIF4A2. Then, SVM-RFE was added, and together with LASSO and Random Forest, a hub gene (EIF4A2) out of the 17 signature genes was revealed. Lastly, in a schizophrenia rat model, the EIF4A2 expression levels were reduced in the model rat brains in a brain-regional dependent manner, but can be reversed by risperidone. In conclusion, by using various bioinformatic and biological methods, this study found 17 immune-related signature genes and a hub gene of schizophrenia that might be potential diagnostic biomarkers and therapeutic targets of schizophrenia.

A comprehensive metabolomic and lipidomic study of olanzapine in the treatment of first-episode schizophrenia

BACKGROUND

Despite advances in research, critical gaps remain in understanding the molecular mechanisms of antipsychotic medications such as olanzapine. This study investigated the molecular pathways by which olanzapine exerts its therapeutic effects and causes metabolic side effects by analyzing changes in the serum metabolic and lipid profiles of patients with first-episode schizophrenia.

METHODS

Clinical symptoms were assessed using the Positive and Negative Symptom Scale (PANSS) in 43 patients with first-episode schizophrenia. Body mass index (BMI) and fasting glucose (GLU) and tetraplex lipids levels were measured before and after treatment. Changes in patient serum metabolic and lipid profiles before and after treatment were examined. Correlation analysis was used to identify differential metabolites and lipid molecules that were significantly associated with changes in clinical symptoms and metabolic side-effect indicators.

RESULTS

After 8 weeks of olanzapine treatment, there was a significant decrease in all PANSS scores and a significant increase in BMI and GLU, total cholesterol, and low-density lipoprotein cholesterol levels in patients with first-episode schizophrenia. Metabolomic and lipidomic analyses identified 70 metabolites and 67 lipids in the serum that changed significantly after treatment. Correlation analysis revealed that the clinical symptom changes in the patients before and after treatment were significantly associated with 11 metabolites (most related to inflammation and oxidative stress), while the metabolic side-effect indicators were significantly associated with 14 lipid molecules.

CONCLUSIONS

Olanzapine may improve psychotic symptoms by modulating inflammation and oxidative stress-related metabolites; however, olanzapine may also cause metabolic disturbances by affecting lipid metabolic pathways.

Identifying periphery biomarkers of first-episode drug-naïve patients with schizophrenia using machine-learning-based strategies

Schizophrenia is a complex mental disorder. Accurate diagnosis and classification of schizophrenia has always been a major challenge in clinic due to the lack of biomarkers. Therefore, identifying molecular biomarkers, particularly in the peripheral blood, is of great significance. This study aimed to identify immune-related molecular biomarkers of schizophrenia in peripheral blood. Eighty-four Peripheral blood leukocytes of first-episode drug-naïve (FEDN) patients with schizophrenia and 97 healthy controls were collected and examined using high-throughput RNA-sequencing. Differentially-expressed genes (DEGs) were analysed. Weighted correlation network analysis (WGCNA) was employed to identify schizophrenia-associated module genes. The CIBERSORT algorithm was adopted to analyse immune cell proportions. Then, machine-learning algorithms including random forest, LASSO, and SVM-RFE were employed to screen immune-related predictive genes of schizophrenia. The RNA-seq analyses revealed 734 DEGs. Further machine-learning-based bioinformatic analyses screened out three immune-related predictive genes of schizophrenia (FOSB, NUP43, and H3C1), all of which were correlated with neutrophils and natural killer cells resting. Lastly, external GEO datasets were used to verify the performance of the machine-learning models with these predictive genes. In conclusion, by analysing the peripheral mRNA expression profiles of FEDN patients with schizophrenia, this study identified three predictive genes that could be potential molecular biomarkers for schizophrenia.

Neurobiological perturbations in bipolar disorder compared to schizophrenia - evidence from cell cultures and brain organoids

Bipolar disorder (BD) and schizophrenia (SCZ) are uniquely human disorders with a complex pathophysiology which involves adverse neuropathological events in brain development. High disease polygenicity and limited access to live human brain tissue make these disorders exceedingly challenging to study mechanistically. Cellular cultures and brain organoids generated from human-derived pluripotent stem cells preserve the genetic background of the donor cells and recapitulate some of the defining characteristics of human brain architecture and early spatiotemporal development. These model systems have already proven successful in deciphering some of the neuropathological perturbations in BD and SCZ, and methodological advancements, such as the functional integration of two or more region-specific organoids and organoid transplantation in animals, promise to deliver increasingly refined insights. Here we review a selection of recent discoveries achieved by stem cell-based models, with a particular focus on patterns of cellular and molecular convergence and divergence between BD and SCZ. We first provide a brief overview of the evidence from glial and neuronal cell cultures and brain organoids, centering our discussion on several key functional domains, including neuroinflammation, neuronal excitability, and mitochondrial function. We then review recent findings demonstrating the power of integrating stem cell-based systems with gene editing technologies to elucidate the functional consequences of risk variants identified through genetic association studies. We end with a discussion of current challenges and some promising avenues for future research.

Behavioral Abnormalities, Cognitive Impairments, Synaptic Deficits, and Gene Replacement Therapy in a CRISPR Engineered Rat Model of 5p15.2 Deletion Associated With Cri du Chat Syndrome

The Cri du Chat Syndrome (CdCS), a devastating genetic disorder caused by a deletion on chromosome 5p, faces challenges in finding effective treatments and accurate animal models. Using CRISPR-Cas9, a novel CdCS rat model with a 2q22 deletion is developed, mirroring a common genetic alteration in CdCS patients. This model exhibits pronounced deficits in social behavior, cognition, and anxiety, accompanied by neuronal abnormalities and immune dysregulation in key brain regions such as the hippocampus and medial prefrontal cortex (mPFC). The immunostaining and RNA-seq analyses provide new insights into CdCS pathogenesis, revealing inflammatory and immune processes. Importantly, it is demonstrated that early gene replacement therapy with AAV-Ctnnd2 alleviates cognitive impairments in CdCS rats, highlighting the potential for early intervention. However, the effectiveness of this therapy is confined to the early developmental stages and does not fully restore all CdCS symptoms. The findings deepen the understanding of CdCS pathogenesis and suggest promising therapeutic directions.

Lights and shadows of clozapine on the immune system in schizophrenia: a narrative literature review

Schizophrenia is a chronic mental disorder and one of the main causes of disability in the world. Approximately 1% of the general population suffers from this disorder, and almost 30% of cases are unresponsive to antipsychotic therapies. Clozapine is a Food and Drug Administration (FDA)-approved antipsychotic drug for treatment-resistant schizophrenia (TRS). Clozapine is also approved for the prevention of suicide associated with schizophrenia. However, clozapine is not the preferred first-line medication because of its potential AEs, including agranulocytosis, metabolic syndromes, and myocarditis. Clozapine prescription requires weekly absolute neutrophil count (ANC) monitoring for the first six months, followed by biweekly monitoring until the patient has finished one year of treatment. Several psychiatric disorders have been reported to be associated with inflammatory biomarkers. Dysregulation of the immune system and the elevation of pro-inflammatory cytokines were also reported to be associated with schizophrenia, highlighting the necessity of further research into the etiology of the disease and the relationship between the immune system and clozapine-responsiveness to support better management of symptoms and potential AEs. In this framework, we searched PubMed using the medical subject headings (MeSH) terms "clozapine", "antipsychotics", "schizophrenia", "treatment-resistant schizophrenia", "immune system", "inflammation", "neuroinflammation", "biomarker", "cytokine", and "chemokine" with the aim of overview the impact of clozapine on the immune system in individuals with treatment-responsive and treatment-resistant schizophrenia.

Current Strategies and Future Directions of Wearable Biosensors for Measuring Stress Biochemical Markers for Neuropsychiatric Applications

Most wearable biosensors aimed at capturing psychological state target stress biomarkers in the form of physical symptoms that can correlate with dysfunction in the central nervous system (CNS). However, such markers lack the specificity needed for diagnostic or preventative applications. Wearable biochemical sensors (WBSs) have the potential to fill this gap, however, the technology is still in its infancy. Most WBSs proposed thus far target cortisol. Although cortisol detection is demonstrated as a viable method for approximating the extent and severity of psychological stress, the hormone also lacks specificity. Multiplex WBSs that simultaneously target cortisol alongside other viable stress-related biochemical markers (SBMs) can prove to be indispensable for understanding how psychological stress contributes to the pathophysiology of neuropsychiatric illnesses (NPIs) and, thus, lead to the discovery of new biomarkers and more objective clinical tools. However, none target more than one SBM implicated in NPIs. Till this review, cortisol's connection to dysfunctions in the CNS, to other SBMs, and their implication in various NPIs has not been discussed in the context of developing WBS technology. As such, this review is meant to inform the biosensing and neuropsychiatric communities of viable future directions and possible challenges for WBS technology for neuropsychiatric applications.

Peering into the mind: unraveling schizophrenia's secrets using models

Schizophrenia (SCZ) is a complex mental disorder characterized by a range of symptoms, including positive and negative symptoms, as well as cognitive impairments. Despite the extensive research, the underlying neurobiology of SCZ remain elusive. To overcome this challenge, the use of diverse laboratory modeling techniques, encompassing cellular and animal models, and innovative approaches like induced pluripotent stem cell (iPSC)-derived neuronal cultures or brain organoids and genetically engineered animal models, has been crucial. Immortalized cellular models provide controlled environments for investigating the molecular and neurochemical pathways involved in neuronal function, while iPSCs and brain organoids, derived from patient-specific sources, offer significant advantage in translational research by facilitating direct comparisons of cellular phenotypes between patient-derived neurons and healthy-control neurons. Animal models can recapitulate the different psychopathological aspects that should be modeled, offering valuable insights into the neurobiology of SCZ. In addition, invertebrates' models are genetically tractable and offer a powerful approach to dissect the core genetic underpinnings of SCZ, while vertebrate models, especially mammals, with their more complex nervous systems and behavioral repertoire, provide a closer approximation of the human condition to study SCZ-related traits. This narrative review provides a comprehensive overview of the diverse modeling approaches, critically evaluating their strengths and limitations. By synthesizing knowledge from these models, this review offers a valuable source for researchers, clinicians, and stakeholders alike. Integrating findings across these different models may allow us to build a more holistic picture of SCZ pathophysiology, facilitating the exploration of new research avenues and informed decision-making for interventions.

NLRP3 inflammasome mediates astroglial dysregulation of innate and adaptive immune responses in schizophrenia

Mounting evidence indicates the involvement of neuroinflammation in the development of schizophrenia (SCZ), but the potential role of astroglia in this phenomenon remains poorly understood. We assessed the molecular and functional consequences of inflammasome activation using induced pluripotent stem cell (iPSC)-derived astrocytes generated from SCZ patients and healthy controls (CTRL). Screening protein levels in astrocytes at baseline identified lower expression of the NLRP3-ASC complex in SCZ, but increased Caspase-1 activity upon specific NLRP3 stimulation compared to CTRL. Using transcriptional profiling, we found corresponding downregulations of NLRP3 and ASC/PYCARD in both iPSC-derived astrocytes, and in a large (n = 429) brain postmortem case-control sample. Functional analyses following NLRP3 activation revealed an inflammatory phenotype characterized by elevated production of IL-1β/IL-18 and skewed priming of helper T lymphocytes (Th1/Th17) by SCZ astrocytes. This phenotype was rescued by specific inhibition of NLRP3 activation, demonstrating its dependence on the NLRP3 inflammasome. Taken together, SCZ iPSC-astrocytes display unique, NLRP3-dependent inflammatory characteristics that are manifested via various cellular functions, as well as via dysregulated innate and adaptive immune responses.

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.

What is the relationship between exposure to environmental pollutants and severe mental disorders? A systematic review on shared biological pathways

Severe mental disorders are multi-dimensional constructs, resulting from the interaction of genetic, biological, psychosocial, and environmental factors. Among the latter, pollution and climate change are frequently being considered in the etiopathogenesis of severe mental disorders. This systematic review aims to investigate the biological mechanisms behind the relationship between environmental pollutants, climate change, and mental disorders. An extensive literature search was performed on PubMed, Scopus, and APA PsycInfo databases according to the PRISMA guidelines. Articles were considered eligible if they involved humans or animals examining the association between exposure to environmental pollutants and if the resulting biological mechanisms that may have an impact on mental health and may support or even cause severe mental disorders (SMD) are assessed. For this reason, only studies dealing with biomarkers or biological pathways were taken into account. The 47 papers included in the review were divided into two groups: those conducted on human participants (15 studies) and those utilizing animal models (31 studies); one study included both humans and animals. Studies carried out with humans, which are mainly focused on measuring the impact of particulate matter (PM2.5 and PM10) exposure on mental health, showed an increased risk of depression or psychotic relapses through the inflammation and oxidative stress pathways, or through the alteration of the hypothalamic-pituitary-adrenal (HPA) axis. Animal models showed the potential impact of pollution on brain functioning through increased inflammatory responses, oxidative stress, HPA axis disruption, hippocampal damage, and neurotransmitters dysregulation. Our findings show that environmental pollutants have an impact on human mental health through different biological pathways. The biological mechanisms by which environmental pollution and climate change influence the onset and exacerbation of severe mental disorders are complex and include gene expression, inflammation, oxidative stress, and anatomical brain changes. A better understanding of those pathways is important for the progress of knowledge on the pathophysiology of severe mental disorders according to the one health model, that promotes a collaborative, multisectoral, and transdisciplinary approach across various levels to optimize health outcomes by recognizing the interconnectedness of humans, animals, plants, and their shared environment.

Inflammation biomarkers and neurobehavioral performance in rural adolescents

Background

Systemic inflammation has been associated with lower neurobehavioral performance in diverse populations, yet the evidence in adolescents remains lacking. Cytokines can alter neural network activity to induce neurocognitive changes. This work seeks to investigate the association between inflammation and neurobehavior in adolescents living in a rural region of Ecuador.

Methods

We examined 535 adolescents in rural communities of Ecuador (ESPINA study), 508 of which had neurobehavioral assessments (NEPSY-II) and circulating plasma levels of inflammatory markers (CRP, IL-6, TNF-⍺, sICAM-1, sVCAM-1, SAA, and sCD14). Associations between inflammatory biomarker concentrations and neurobehavioral scores were examined using adjusted bivariate semi-parametric models with generalized estimating equations. A partial least squares regression approach was used to create composite variables from multiple inflammation biomarkers and model their association with cognitive outcomes.

Results

Higher sCD14 and TNF-α concentrations were significantly associated with lower social perception scores, by -0.465 units (95% CI: -0.80, -0.13) and -0.418 units (-0.72, -0.12) for every 50% increase in inflammatory marker concentration, respectively. Similarly, every 50% increase in the inflammation summary score was associated with a significantly lower Social Perception score by -0.112 units (-0.19, -0.03). A greater inflammatory composite variable from seven markers was associated with lower scores in language (β = -0.11, p = 0.043), visuospatial processing (β = -0.15, p = 0.086), and social perception (β = -0.22, p = 0.005) domains.

Conclusions

Higher levels of inflammation were associated with lower neurobehavioral performance in adolescents, especially with social perception. In addition, using a robust analytic method to examine an association between a composite inflammatory variable integrating seven markers led to additional findings, including the domains of language and visuospatial processing. A longitudinal follow-up of such investigations could unveil potential changes in inflammation-neurobehavior performance links through developmental stages and intervention opportunities.

Genomics-driven integrative analysis highlights immune-related plasma proteins for psychiatric disorders

BACKGROUND

Genome-wide association studies (GWAS) have identified numerous variants associated with psychiatric disorders. However, it remains largely unknown on how GWAS risk variants contribute to psychiatric disorders.

METHODS

Through integrating two largest, publicly available, independent protein quantitative trait loci datasets of plasma protein and nine large-scale GWAS summary statistics of psychiatric disorders, we first performed proteome-wide association study (PWAS) to identify psychiatric disorders-associated plasma proteins, followed by enrichment analysis to reveal the underlying biological processes and pathways. Then, we conducted Mendelian randomization (MR) and Bayesian colocalization (COLOC) analyses, with both discovery and parallel replication datasets, to further identify protein-disorder pairs with putatively causal relationships. We finally prioritized the potential drug targets using Drug Gene Interaction Database.

RESULTS

PWAS totally identified 112 proteins, which were significantly enriched in biological processes relevant to immune regulation and response to stimulus including regulation of immune system process (adjusted P = 1.69 × 10-7) and response to external stimulus (adjusted P = 4.13 × 10-7), and viral infection related pathways, including COVID-19 (adjusted P = 2.94 × 10-2). MR and COLOC analysis further identified 26 potentially causal protein-disorder pairs in both discovery and replication analysis. Notably, eight protein-coding genes were immune-related, such as IRF3, CSK, and ACE, five among 16 druggable genes were reported to interact with drugs, including ACE, CSK, PSMB4, XPNPEP1, and MICB.

CONCLUSIONS

Our findings highlighted the immunological hypothesis and identified potentially causal plasma proteins for psychiatric disorders, providing biological insights into the pathogenesis and benefit the development of preventive or therapeutic drugs for psychiatric disorders.

Ambient coarse particulate matter pollution and hospital admissions for schizophrenia

OBJECTIVE

To investigate the association between ambient coarse particulate matter (PM2.5-10) pollution and risk of acute schizophrenia episodes.

METHODS

A time-stratified case-crossover study with a two-stage analytical approach was conducted to investigate the association between ambient PM2.5-10 pollution and schizophrenia admissions (an indicator for acute schizophrenia episodes) across 259 Chinese cities of prefecture-level or above during 2013-2017. A conditional logistic regression model was constructed to estimate city-specific changes in hospital admissions for schizophrenia associated with per interquartile range (IQR) increase in ambient PM2.5-10, and the overall associations were obtained by pooling the city-specific associations using the random-effects model.

RESULTS

A total of 817,296 schizophrenia admissions were included in the analysis. Per IQR increase (28.43 μg/m3) in PM2.5-10 at lag01 was associated with an increase of 1.66 % (95 % CI: 0.68 %, 2.65 %) in schizophrenia admissions. Compared to concentrations <30 μg/m3, PM2.5-10 concentrations of 30-49 μg/m3 and ≥50 μg/m3 were associated with increases of 2.25 % (95 % CI: 0.73 %%, 3.79 %) and 4.03 % (95 % CI: 1.92 %, 6.18 %) in schizophrenia admissions, respectively. City-level urbanization has the potential to attenuate the association between ambient PM2.5-10 and schizophrenia admissions (P = 0.0002).

CONCLUSIONS

Our study provides novel evidence for the acute adverse effects of ambient PM2.5-10 on schizophrenia and calls for special attention on the control of high PM2.5-10 pollution in disease prevention.

Causal relationship between mental disorders and abdominal aortic aneurysm: Insights from the genetic perspective

BACKGROUND

This study aims to investigate the genetic link between mental disorders-depression, schizophrenia (SCZ), and bipolar disorder (BIP)-and abdominal aortic aneurysm (AAA).

METHODS

We first examined the genetic associations between AAA and mental disorders by analyzing global and local genetic correlations as well as shared genomic loci. Global genetic correlation was assessed using linkage disequilibrium score regression (LDSC) and the GeNetic cOVariance Analyzer (GNOVA), while local genetic correlation was analyzed using the SUPERGNOVA approach. To identify shared genetic variants, the pleiotropy-informed conditional and conjunctional false discovery rate (pleioFDR) method was applied. Subsequently, the univariate Mendelian Randomization (UMR) was employed to evaluate the causal relationship, complemented by multivariate MR (MVMR) to account for potential confounding biases. Additionally, mediation analysis was performed to determine whether known risk factors mediate the identified causal relationships.

RESULTS

Global correlations showed positive links between depression, SCZ, and AAA, but not BIP. Local analyses identified specific genomic regions of correlation. We found 26, 141, and 10 shared loci for AAA with depression, SCZ, and BIP, respectively. UMR indicated significant associations between genetically predicted depression (OR 1.270; 95 % CI 1.071-1.504; p = 0.006) and SCZ (OR 1.047; 95 % CI 1.010-1.084; p = 0.011) with AAA, but not BIP. These results were confirmed by MVMR analyses. Mediation analyses showed that smoking, hypertension, hyperlipidemia, and coronary atherosclerosis mediated the impact of depression on AAA while smoking mediated SCZ's impact.

CONCLUSION

This study provides evidence that genetically predicted depression and SCZ are linked to an increased risk of AAA, mediated by traditional AAA risk factors.

Comprehensive bioinformatics analysis identifies hub genes associated with immune cell infiltration in early-onset schizophrenia

BACKGROUND

Early-onset schizophrenia (EOS) occurs between the ages of 13 and 17 years, and neurobiological factors leading to cognitive deficits and psychotic symptoms with varying degrees of positive and negative symptoms. Numerous studies have demonstrated a broad link between immune dysregulation and the central nervous system in EOS, and its pathogenesis involves immune dysfunction, but the exact biological mechanisms have not been elucidated. This study employs immune infiltration analysis and bioinformatics to unveil the pathogenic mechanisms of EOS and identify potential diagnostic biomarkers, aiming for more precise clinical interventions.

METHODS

In this study, we recruited 26 EOS patients and 27 healthy controls (HCs), and microarray data were collected. Crossover genes were identified using weighted gene co-expression network analysis (WGCNA) and differential expression genes (DEGs) analysis. These genes were subjected to genome enrichment analysis (GSEA) and gene ontology (GO) analysis. Hub genes were identified through protein-protein interactions (PPIs) and the GeneMANIA database. The diagnostic potential of immune-associated hub genes was evaluated using ROC analysis. Immune infiltration in EOS was analyzed with CIBERSORT. Regulatory miRNAs for the hub genes were predicted using miRNet, and the correlation between mRNAs and miRNAs was analyzed and validated in clinical samples.

RESULTS

By WGCNA and DEGs analysis, 330 relevant genes were screened in EOS patients compared to HCs. Functional enrichment analysis using Metascape showed significant enrichment in immune system pathways. Subsequently, a PPI network was constructed to select the top 10 potential hub genes, and functional analysis was performed by GeneMANIA, resulting in the identification of four immune-related genes. In addition, significant differences were observed among the four immune cell types in the two groups of samples. ROC analysis showed clinical relevance of the immune-related hub genes, and the AUC of all genes was greater than 0.7. A miRNA-mRNA regulatory network was constructed from miRNA data, and three miRNAs were found to be significantly associated with the immune-related hub genes.

CONCLUSION

Our findings demonstrated that CCL3, IL1B, CXCL8, CXCL10 and miR-34a-5p may be biomarkers that play crucial roles in the underlying mechanisms of EOS immune-related pathways. These findings contribute to the understanding of EOS pathophysiology and may help identify new diagnostic and therapeutic targets.

The role of ferroptosis and oxidative stress in cognitive deficits among chronic schizophrenia patients: a multicenter investigation

Oxidative stress (OS) is crucial in schizophrenia (SCZ) pathology. Ferroptosis, a recently discovered cell death pathway linked to OS, might contribute to the development of SCZ. This study investigated the association between ferroptosis markers and cognitive impairments in chronic SCZ patients. A retrospective analysis was conducted on 204 chronic SCZ patients with cognitive deficits and 216 healthy controls (HC) matched for relevant characteristics. Plasma levels of ferroptosis and OS markers, including iron, ferritin (FE), transferrin (TF), glutathione peroxidase 4 (GPX4), long-chain acyl-CoA synthetase 4 (ACSL4), glutathione (GSH), sirtuin 1 (SIRT1), nuclear factor erythroid 2-related factor 2 (Nrf2), malondialdehyde (MDA), and superoxide dismutase (SOD) were measured. Standardized assessments like the positive and negative syndrome scale (PANSS), and Montreal Cognitive Assessment (MoCA) were used to evaluate psychiatric symptoms, and cognitive function. SCZ patients showed significant differences in markers compared to the HC group (P < 0.01). Multiple linear regression analysis revealed that decreased GSH and iron levels, along with elevated SOD levels, were significantly associated with the overall severity of psychiatric symptoms. Additionally, reduced GPX4 levels and increased ACSL4 and FE levels were significantly linked to negative symptoms and cognitive impairments. Notably, GPX4 emerged as a key predictor for cognitive function in abstraction and language domains. Our study revealed alterations in the altered plasma levels of GPX4, GSH, iron, ACSL4, FE, and SOD in chronic SCZ patients, which might indicate a close association between biomarkers of ferroptosis and OS and the psychiatric symptoms and cognitive deficits observed in these individuals.

Inflammation proteomic profiling of psychosis in young adults: Findings from the ALSPAC birth cohort

Psychotic disorder is associated with altered levels of various inflammatory markers in blood, but existing studies have typically focused on a few selected biomarkers, have not examined specific symptom domains notably negative symptoms, and are based on individuals with established/chronic illness. Based on data from young people aged 24 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK birth cohort, we have examined the associations of 67 plasma immune/inflammatory proteins assayed using the Olink Target 96 Inflammation panel with psychotic disorder, positive (any psychotic experiences and definite psychotic experiences) and negative symptoms, using linear models with empirical Bayes estimation. The analyses included between 2317 and 2854 individuals. After adjustment for age, sex, body mass index and smoking and correction for multiple testing, positive symptoms and psychotic disorder were consistently associated with upregulation of CDCP1 and IL-6, and psychotic disorder was additionally associated with upregulation of MMP-10. Negative symptoms were associated with upregulation of CDCP1 and TRAIL. CDCP1 and MMP-10 are novel markers of psychosis identified in this study, and are involved in immune regulation, immune cell activation/migration, blood-brain barrier disruption, and extracellular matrix abnormalities. Our findings highlight psychosis symptom domains have overlapping and distinct immune associations, and support a role of inflammation and immune dysfunction in the pathogenesis of psychosis.

Peripheral blood complement factors C2 and C3 as biomarkers of clinical efficacy in patients with first-episode schizophrenia after aripiprazole treatment

OBJECTIVE

The objective of this study was to identify serum complement factor-based biomarkers indicative of clinical efficacy in patients with first-episode schizophrenia (SCZ) following treatment with aripiprazole.

METHODS

The retrospective study cohort comprised 40 patients diagnosed with first-episode SCZ (SCZ group) and 40 healthy individuals (control group). Quantitative analyses were conducted on five complement factors, namely complement component 1 (C1), C2, C3, C4, and the 50% hemolytic complement (CH50). Baseline serum complement factor levels were compared between the SCZ and control groups. Patients diagnosed with SCZ underwent a 4-week treatment regimen with aripiprazole. The severity of psychiatric symptoms in these patients was assessed using the Positive and Negative Symptom Scale (PANSS) and the Brief Psychiatric Rating Scale-18 Item Version (BPRS). Comparative analyses were conducted on PANSS and BPRS scores, as well as serum complement factor levels, both prior to (pre-treatment group) and following aripiprazole administration (post-treatment group). Pearson's correlation test was employed to evaluate the relationships between changes in serum complement factor levels and the reduction rates of PANSS/BPRS scores.

RESULTS

At baseline, patients with SCZ exhibited significantly elevated levels of C1, C2, C3, C4, and CH50 compared to the control group (P < 0.05). Moreover, following treatment, there was a significant reduction in the PANSS total score, positive symptom score, negative symptom score, and BPRS score in the post-treatment group compared to the pre-treatment group (P < 0.05). Furthermore, patients in the post-treatment group exhibited a significant reduction in serum levels of C2, C3, and C4, alongside a significant increase in the serum level of CH50 compared to those in the pre-treatment group (P < 0.05). Additionally, the baseline serum C2 levels and the variations in serum C2 levels pre- and post-treatment exhibited a negative correlation with the reduction rate of PANSS/BPRS scores (P < 0.05). Similarly, both the baseline serum C3 levels and the changes in serum C3 levels pre- and post-treatment were negatively correlated with the reduction rate of PANSS/BPRS scores (P < 0.05).

CONCLUSION

Baseline serum levels of C2 and C3, as well as their variations pre- and post-treatment, may serve as biomarkers for predicting clinical efficacy in patients with first-episode SCZ undergoing treatment with aripiprazole.

The Role of Neuroglia in the Development and Progression of Schizophrenia

Schizophrenia is a complex heterogenous disorder thought to be caused by interactions between genetic and environmental factors. The theories developed to explain the etiology of schizophrenia have focused largely on the dysfunction of neurotransmitters such as dopamine, serotonin and glutamate with their receptors, although research in the past several decades has indicated strongly that other factors are also involved and that the role of neuroglial cells in psychotic disorders including schizophrenia should be given more attention. Although glia were originally thought to be present in the brain only to support neurons in a physical, metabolic and nutritional capacity, it has become apparent that these cells have a variety of important physiological roles and that abnormalities in their function may make significant contributions to the symptoms of schizophrenia. In the present paper, we review the interactions of brain microglia, astrocytes and oligodendroglia with aspects such as transmitter dysregulation, neuro-inflammation, oxidative stress, synaptic function, the gut microbiome, myelination and the blood-brain barrier that appear to affect the cause, development and treatment of schizophrenia. We also review crosstalk between microglia, astrocytes and oligodendrocytes and the effects of antipsychotics on neuroglia. Problems associated with studies on specific biomarkers for glia in schizophrenia are discussed.

Increased GDF-15 in chronic male patients with schizophrenia: correlation with body mass index and cognitive impairment

Growth Differentiation Factor-15 (GDF-15) is a pleiotropic cytokine that plays a significant role in metabolism and inflammation. Elevated serum levels of GDF-15 have been associated with mood disorders. We propose that GDF-15 may potentially influence cognitive impairment and metabolism in male patients with chronic schizophrenia (CS), although there is limited research on this topic. This study compared serum GDF-15 levels in 72 male patients with CS and 85 healthy controls (HC). The severity of psychotic symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS), while cognitive performance was evaluated with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The male CS patients performed worse than the healthy controls in both the total score and all subscales of the RBANS. Serum GDF-15 concentrations were significantly higher in the male CS patients compared to the healthy controls. Furthermore, the log-transformed serum GDF-15 concentrations in male CS patients were positively correlated with BMI and negatively correlated with Delayed Memory scores, Immediate Memory, and the total RBANS score. This preliminary study suggests that elevated serum GDF-15 levels in male patients with chronic schizophrenia may play a role in cognitive function and BMI regulation.

Association between psychiatric symptoms with multiple peripheral blood sample test: a 10-year retrospective study

Background

Psychiatric illness is thought to be a brain somatic crosstalk disorder. However, the existing phenomenology-based Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnostic framework overlooks various dimensions other than symptoms. In this study, we investigated the associations between peripheral blood test indexes with various symptom levels of major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SCZ) to explore the availability of peripheral blood test indexes.

Methods

We extracted cases diagnosed with MDD, BD, and SCZ at West China Hospital from 2009 to 2021, translated their main complaints into Research Domain Criteria (RDoC) symptom severity scores using nature language processing (NLP), and collected their detailed psychiatric symptoms and peripheral blood test results. Then, generalized linear models were performed between seven types of peripheral blood test values with their transformed RDoC scores and detailed symptom information adjusted for age, gender, smoking, and alcohol history.

Results

Several inflammatory-related indexes were strongly associated with the negative valence system (NVS) domain (basophil percentage adjusted β = 0.275, lymphocyte percentage adjusted β = 0.271, monocyte percentage adjusted β = 0.223, neutrophil percentage adjusted β = -0.310, neutrophil count adjusted β = -0.301, glucose adjusted β = -0.287, leukocyte count adjusted β = -0.244, NLR adjusted β = -0.229, and total protein adjusted β = -0.170), the positive valence system (PVS) domain (monocyte percentage adjusted β = 0.228, basophil count adjusted β = 0.176, and glutamyl transpeptidase adjusted β = 0.171), and a wide range of mood, reward, and psychomotor symptoms. In addition, glucose, urea, urate, cystatin C, and albumin showed considerable associations with multiple symptoms. In addition, based on the direction of associations and the similarity of symptoms in terms of RDoC thinking, it is suggested that "positive" mood symptoms like mania and irritability and "negative" mood symptoms like depression and anxiety might be on a continuum considering their opposite relationships with similar blood indexes.

Limitations

The cross-sectional design, limited symptoms record, and high proportion of missing values in some other peripheral blood indexes limited our findings.

Conclusion

The proportion of high inflammatory indexes in SCZ was relatively high, but in terms of mean values, SCZ, BD, and MDD did not differ significantly. Inflammatory response showed a strong correlation with NVS, PVS, and a range of psychiatric symptoms especially mood symptoms, psychomotor symptoms, and cognitive abilities.

α-linolenic acid mitigates microglia-mediated neuroinflammation of schizophrenia in mice by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin 2

BACKGROUND

Schizophrenia (SCZ) is a heterogeneous psychiatric disorder that is poorly treated by current therapies. Emerging evidence indicates that SCZ is closely correlated with a persistent neuroinflammation. α-linolenic acid (ALA) is highly concentrated in the brain and represents a modulator of the immune system by decreasing the inflammatory response in chronic metabolic diseases. This study was first designed to investigate the potential role of dietary ALA on cognitive function and neuroinflammation in mice with SCZ.

METHODS

In vivo, after 2 weeks of modeling, mice were treated with dietary ALA treatment for 6 weeks. In vitro, inflammation model was created using lipopolysaccharide as an inducer in BV2 microglial cells.

RESULTS

Our results demonstrated that ALA alleviated cognitive impairment and enhanced synaptic plasticity in mice with SCZ. Moreover, ALA mitigated systematic and cerebral inflammation through elevating IL-10 and inhibiting IL-1β, IL-6, IL-18 and TNF-α. Furthermore, ALA notably inhibited microglia and pro-inflammatory monocytes, as well as microglial activation andpolarization. Mechanistically, ALA up-regulated the expressions of G protein coupled receptor (GPR) 120 and associated β-inhibitor protein 2 (β-arrestin2), accompanied by observable weakened levels of transforming growth factor-β activated kinase 1 (TAK1), NF-κB p65, cysteine proteinase-1 (caspase-1), pro-caspase-1, associated speck-like protein (ASC) and NLRP3. In vitro, ALA directly restrained the inflammation of microglia by decreasing the levels of pro-inflammatory factors and regulating microglial polarization via GPR120-NF-κB/NLRP3inflammasome signaling pathway, whereas AH7614 definitely eliminated this anti-inflammatory effect of ALA.

CONCLUSION

Dietary ALA ameliorates microglia-mediated neuroinflammation by suppressing the NF-κB/NLRP3 pathway via binding GPR120-β-arrestin2.

Neuroinflammation and kynurenines in schizophrenia: Impact on cognition depending on cognitive functioning and modulatory properties in relation to cognitive remediation and aerobic exercise

Background

In the last decade, the kynurenine pathway (KP) has gained attention in the pathogenesis of cognitive impairment in schizophrenia being at the croassroad between neuroinflammation and glutamatergic and cholinergic neurotransmission. However, clinical findings are scarse and conflicting, and the specific contributions of these two systems to the neurobiology of cognitive symptoms are far from being elucidated. Furthermore, little is known about the molecular underpinnings of non-pharmacological interventions for cognitive improvement, including rehabilitation strategies.

Methods

The current study examined 72 patients with schizophrenia, divided in two clusters depending on the severity of the cognitive impairment, with the aim to evaluate the impact of inflammatory biomarkers and KP metabolites depending on cognitive functioning. Moreover, we studied their possible link to the cognitive outcome in relation to sessions of cognitive remediation therapy (CRT) and aerobic exercise (AE) in a longitudinal arm of 42 patients.

Results

Neuroinflammation appeared to exert a more pronounced influence on cognition in patients exhibiting a higher cognitive functioning, contrasting with the activation of the KP, which had a greater impact on individuals with a lower cognitive profile. Cognitive improvements after the treatments were negatively predicted by levels of TNF-α and positively predicted by the 3-hydroxykynurenine (3-HK)/kynurenine (KYN) ratio, an index of the kynurenine-3-monooxygenase (KMO) enzyme activity.

Conclusion

Overall, these findings add novel evidence on the biological underpinnings of cognitive impairment in schizophrenia pointing at a differential role of neuroinflammation and KP metabolites in inducing cognitive deficits depending on the cognitive reserve and predicting outcomes after rehabilitation.

Risperidone-induced bioenergetic disruption in the isolated human peripheral blood monocytes

Risperidone (RIS) is a widely used antipsychotic drug with reported alteration in immune response. The current study investigated mitochondrial disruption as the underlying mechanism of RIS-induced immunotoxicity in isolated human peripheral blood monocytes (hPBM). RIS was cytotoxic to hPBM in exposure duration and concentration-dependent patterns. Functionally, RIS was shown to increase the release of IL-6, TNF-α, and IL-8 with a decrease in test particle phagocytosis in concertation and exposure time-based patterns. It was found that RIS decreased ATP production in isolated monocytes' mitochondria, with an estimated EC50 of around 70 μM after 24 h with parallel inhibition of mitochondrial complexes I and III activities and decreased mitochondrial membrane potential and oxygen consumption rates with increased lactate production from by the treated cells in comparison to controls. Structurally, RIS in 100 μM concentration significantly increased the mitochondrial membrane fluidity with significant increase in increased unsaturated/saturated fatty acids ratios of the mitochondrial membranes of the treated cells. Interestingly, water-soluble CoQ10 formulation significantly decreased the cytotoxic effect of RIS and improved the phagocytic activity of RIS-treated cells. To conclude, the current data suggests mitochondrial disruption as the underlying mechanism of RIS-induced immunotoxicity with shown protective effect of water-soluble CoQ10 formulation.

Systematic review of Mendelian randomization studies on antihypertensive drugs

BACKGROUND

We systematically reviewed Mendelian randomization (MR) studies and summarized evidence on the potential effects of different antihypertensive drugs on health.

METHODS

We searched PubMed and Embase for MR studies evaluating the effects of antihypertensive drug classes on health outcomes until 22 May 2024. We extracted data on study characteristics and findings, assessed study quality, and compared the evidence with that from randomized controlled trials (RCTs).

RESULTS

We identified 2643 studies in the search, of which 37 studies were included. These studies explored a wide range of health outcomes including cardiovascular diseases and their risk factors, psychiatric and neurodegenerative diseases, cancer, immune function and infection, and other outcomes. There is strong evidence supporting the protective effects of genetically proxied antihypertensive drugs on cardiovascular diseases. We found strong protective effects of angiotensin-converting enzyme (ACE) inhibitors on diabetes whereas beta-blockers showed adverse effects. ACE inhibitors might increase the risk of psoriasis, schizophrenia, and Alzheimer's disease but did not affect COVID-19. There is strong evidence that ACE inhibitors and calcium channel blockers (CCBs) are beneficial for kidney and immune function, and CCBs showed a safe profile for disorders of pregnancy. Most studies have high quality. RCT evidence supports the beneficial effects of ACE inhibitors and CCBs on stroke, diabetes, and kidney function. However, there is a lack of reliable RCTs to confirm the associations with other diseases.

CONCLUSIONS

Evidence of the benefits and off-target effects of antihypertensive drugs contribute to clinical decision-making, pharmacovigilance, and the identification of drug repurposing opportunities.

Causality between autoimmune diseases and schizophrenia: a bidirectional Mendelian randomization study

BACKGROUND

Observational studies have shown a link between autoimmune diseases and schizophrenia, with conflicting conclusions. Due to the existence of confounding factors, the causal link between autoimmune diseases and schizophrenia is still unknown.

METHOD

We conducted a comprehensive Mendelian randomization (MR) analysis of schizophrenia and ten common autoimmune diseases in individuals of European descent using genome-wide association studies (GWASs). To evaluate the relationships between autoimmune diseases and schizophrenia, inverse variance weighted, MR-RAPS, Bayesian weighted MR, constrained maximum likelihood, debiased IVW, MR-Egger, and weighted median were utilized. Several sensitivity analyses were performed to ensure the reliability of the study's results.

RESULTS

Our findings reveal that genetically predicted ankylosing spondylitis is related to an increased risk of schizophrenia, whereas celiac disease, type 1 diabetes, and systemic lupus erythematosus are associated with a lower risk of schizophrenia. In the reverse MR analysis, our study indicated that genetically predicted schizophrenia is linked to higher risks of ankylosing spondylitis, Crohn's disease, ulcerative colitis, inflammatory bowel disease, and psoriasis. Neither multiple sclerosis nor rheumatoid arthritis have been linked to schizophrenia, and vice versa.

CONCLUSION

Despite contradicting some other observational reports, this study showed support for a causal link between autoimmune diseases and schizophrenia. To gain a better understanding of the mechanisms underlying the development of immune-mediated schizophrenia, additional research is required to identify potential mechanisms identified in observational studies.

High Prevalence of aCL-IgA and aβ2GPI-IgA in Drug-Free Schizophrenia Patients: Evidence of a Potential Autoimmune Link

BACKGROUND/OBJECTIVES

Schizophrenia (SZ) is a complex psychiatric disorder with increasing evidence pointing to an autoimmune component, including the presence of antiphospholipid antibodies (aPLs). This study aims to assess the prevalence of anticardiolipin (aCL) and anti-beta-2 glycoprotein I (aβ2GPI) antibodies, particularly the IgG, IgA, and IgM isotypes, in drug-free SZ patients compared to healthy controls, and explore their possible involvement in the disease's pathophysiology.

METHODS

Eighty SZ patients meeting DSM-IV criteria were recruited, along with 80 matched healthy controls. Serum samples were analyzed using enzyme-linked immunosorbent assays (ELISA) to quantify IgG, IgA, and IgM isotypes of aCL and aβ2GPI.

RESULTS

SZ patients exhibited significantly higher levels of aCL-IgM and aCL-IgA (p < 0.05), as well as elevated aβ2GPI-IgA (22.5%, p < 0.001), compared to controls. No significant differences were observed in the aCL-IgG isotype. Interestingly, 72% of aPL-positive SZ patients were positive for aβ2GPI-IgA, with some also co-expressing multiple isotypes, suggesting a potential link between SZ and antiphospholipid syndrome (APS).

CONCLUSIONS

This study is the first to report a high prevalence of aCL-IgA and aβ2GPI-IgA in SZ patients, highlighting a possible autoimmune involvement in the disease. The presence of multiple aPL isotypes, particularly IgA, suggests a need for further investigation into their role in SZ pathogenesis and their potential association with APS.

Mitochondrial Dysfunction and Cognitive Impairment in Schizophrenia: The Role of Inflammation

BACKGROUND AND HYPOTHESIS

The complex immune-brain interactions and the regulatory role of mitochondria in the immune response suggest that mitochondrial damage reported in schizophrenia (SZ) may be related to abnormalities observed in immune and brain functions.

STUDY DESIGN

Mitochondrial DNA copy number (mtDNA CN), a biomarker of mitochondrial function, was assessed in peripheral blood leukocytes (PBLs) of 121 healthy individuals and 118 SZ patients before and after 8 weeks of antipsychotic treatment, and a meta-analysis related to blood mtDNA CN was conducted. Plasma C-reactive protein (CRP) levels in SZ patients were obtained from the medical record system. Spearman correlation analysis and hierarchical linear regression were used to analyze the relationships among mtDNA CN, CRP levels, and cognitive function. A mediation model was constructed using the PROCESS program.

STUDY RESULTS

Our results revealed the decreased mtDNA CN in PBLs from SZ patients (P = .05). The meta-analysis supported the decreased blood mtDNA CN in SZ patients (P < .01). The mtDNA CN in PBL was positively correlated with working memory (P = .02) and negatively correlated with plasma CRP levels (P = .039). Furthermore, a lower mtDNA CN in PBL in SZ patients was a significant predictor of worse working memory (P = .006). CRP acted as a mediator with an 8.0% effect.

CONCLUSIONS

This study revealed an association between peripheral mitochondrial dysfunction and cognitive impairment in SZ, with inflammation acting as a mediating effect. Therefore, mitochondrial dysfunction might provide novel targets for new treatments for cognitive impairment in SZ.

The effect of clozapine on immune-related biomarkers in schizophrenia patients

Globally, schizophrenia is one of the main causes of disability. Approximately 1 % of the general population suffers from schizophrenia, and 30 % of cases are unresponsive to therapy. Clozapine is the gold standard for therapy-resistant schizophrenia (TRS), yet it has limited effectiveness and serious adverse events in some patients. Because of the possibility of severe neutropenia, clozapine administration requires monthly hematological monitoring in the first four months. Previous investigations have demonstrated the immune system alteration after clozapine treatment in schizophrenia patients. Besides, it has been proposed that clozapine changes the cytokines profile in schizophrenia patients. These findings highlighted the need to learn more about the disease's etiology and investigate the relationship between peripheral immune system markers and clozapine response to support strategies for better treatment outcomes. The time decision-making to start clozapine could be significantly decreased if some biomarkers were developed to assist physicians in anticipating whether a particular patient will respond to the medication. Therefore, this study aimed to comprehensively review the effect of clozapine on immune-related biomarkers in schizophrenia patients.

Elevated levels of peripheral and central nervous system immune markers reflect innate immune dysregulation in autism spectrum disorder

BACKGROUND

Evidence suggests dysregulated immune functions in the pathophysiology of Autism spectrum disorder (ASD), although specific immune mechanisms are yet to be identified.

METHODS

We assessed circulating levels of 25 immune/neuroinflammatory markers in a large ASD sample (n = 151) and matched controls (n = 72) using linear models. In addition, we performed global brain transcriptomics analyses of relevant immune-related genes. We also assessed the expression and function of factors and pathway elements of the inflammasome system in peripheral blood mononuclear cells (PBMC) isolated from ASD and controls using in vitro methods.

RESULTS

We found higher circulating levels of IL-18 and adhesion factors (ICAM-1, MADCAM1) in individuals with ASD relative to controls. Consistent with this, brain levels of ICAM1 mRNA were also higher in ASD compared to controls. Furthermore, we found higher expression/activity of Caspase-1 and the inflammasome sensor NLRP3 in PBMCs in ASD, both at baseline and following inflammatory challenge. This corresponded with higher levels of secreted IL-18, IL-1β, and IL-8, as well as increased expression of adhesion factors following inflammasome activation in ASD PBMC cultures. Inhibition of the NLRP3-inflammasome rescued the observed immune phenotype in ASD in vitro.

CONCLUSION

Our results suggest a role for inflammasome dysregulation in ASD pathophysiology.

What is the neurobiology of schizophrenia?

Schizophrenia spectrum disorders are brain diseases that are developmental dementias (dementia praecox). Their pathology begins in utero with psychosis most commonly becoming evident in adolescence and early adulthood. It is estimated they afflict the U.S. population at a prevalence rate of approximately 0.8%. Genetic studies indicate that these brain diseases are about 80% determined by genes and about 20% determined by environmental risk factors. Inheritance is polygenic with some 270 gene loci having been identified as contributing to the risk for schizophrenia. Interestingly, many of the identified gene loci and gene polymorphisms are involved in brain formation and maturation. The identified genetic and epigenetic risks give rise to a brain in which neuroblasts migrate abnormally, assume abnormal locations and orientations, and are vulnerable to excessive neuronal and synaptic loss, resulting in overt psychotic illness. The illness trajectory of schizophrenia then is one of loss of brain mass related to the number of active psychotic exacerbations and the duration of untreated illness. In this context, molecules such as dopamine, glutamate, and serotonin play critical roles with respect to positive, negative, and cognitive domains of illness. Acutely, antipsychotics ameliorate active psychotic illness, especially positive signs and symptoms. The long-term effects of antipsychotic medications have been debated; however, the bulk of imaging data suggest that antipsychotics slow but do not reverse the illness trajectory of schizophrenia. Long-acting injectable antipsychotics (LAI) appear superior in this regard. Clozapine remains the "gold standard" in managing treatment-resistant schizophrenia.

The association between hematological markers of inflammation and chronic cannabis use: a systematic review and meta-analysis of observational studies

Introduction

Cannabinoids, both natural and synthetic, are a subject of scientific interest. Cannabis is widely used, and its impact on health and the immune system is being studied. The endocannabinoid system influences inflammation, including the Neutrophil-to-Lymphocyte Ratio (NLR), a potential diagnostic tool. Our study investigates the connection between cannabis use and NLR.

Methods

Our systematic review was registered in Prospero (#CRD42023463539). We searched six databases (PubMed, Scopus, Embase, PsycINFO, Web of Science, and CINAHL Complete) for records in English from inception to May 2024. We included observational studies that measured the Neutrophil-to-Lymphocyte Ratio (NLR) in cannabis users and control participants. We used the Newcastle-Ottawa Quality Assessment Scale to assess the quality of the included studies. We selected a random-effects model, and the statistical analysis was performed using Stata software version 17.

Results

Out of a total of 4,054 records, only five articles were selected for inclusion in the meta-analysis. All of these chosen studies utilized a retrospective design. Furthermore, it's worth noting that all of the studies included were of high quality. In five studies involving 3,359 cannabis users and 10,437 non-users, no significant difference in NLR was found (WMD: 0.12 [-0.16, 0.41], I2: 39.89%). Subgroup analysis on healthy and schizophrenia participants didn't show significant NLR differences (p=0.76). Secondary analysis revealed cannabis users had higher Platelet-to-Lymphocyte Ratio (PLR) (67.80 [44.54, 91.06]), neutrophil count (0.68 [0.25, 1.12]), white blood cell count (0.92 [0.43, 1.41]), monocyte count (0.11 [0.05, 0.16]), and Systemic Immune Inflammation Index (SII) (83.48 [5.92, 157.04]) compared to non-users.

Conclusion

Our systematic review and meta-analysis reveal that cannabis use may affect NLR and hematologic parameters, suggesting a potential immune impact. Complex associations exist, requiring further research. Schizophrenia and pro-inflammatory factors are discussed, highlighting the need for ongoing investigation into cannabis-related immune changes and mental health.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023463539.

Inflammation biomarkers and neurobehavioral performance in rural adolescents

Background

Systemic inflammation has been associated with lower neurobehavioral performance in diverse populations, yet the evidence in adolescents remains lacking. Cytokines can alter neural network activity to induce neurocognitive changes. This work seeks to investigate the association between inflammation and neurobehavior in adolescents living in a rural region of Ecuador.

Methods

We examined 535 adolescents in rural communities of Ecuador (ESPINA study), 508 of which had neurobehavioral assessments (NEPSY-II) and circulating plasma levels of inflammatory markers (CRP, IL-6, TNF-⍺, sICAM-1, sVCAM-1, SAA, and sCD14). Associations between inflammatory biomarker concentrations and neurobehavioral scores were examined using adjusted bivariate semi-parametric models with generalized estimating equations. A partial least square regression approach was used to create composite variables from multiple inflammation biomarkers and model their association with cognitive outcomes.

Results

Higher sCD14 and TNF-α concentrations were significantly associated with lower social perception scores, by -0.47 units (95% CI: -0.80, -0.13) and -0.42 (-0.72, -0.12) for every 50% increase in inflammatory marker concentration, respectively. Similarly, every 50% increase in the inflammation summary score was associated with a significantly lower Social Perception score by -0.11 units (-0.19, -0.03). A unit increase in inflammatory composites of seven markers were associated with lower scores in language (-0.11 units, p=0.04), visuospatial processing (-0.15, p= 0.09), and social perception (-0.22, p=0.005) domains.

Conclusions

Higher levels of inflammation were associated with lower neurobehavioral performance in adolescents, especially with social perception. In addition, using a robust analytic method to examine an association between a composite inflammatory variable integrating seven markers led to additional findings, including the domains of language and visuospatial processing. A longitudinal follow-up of such investigations could unveil potential changes in inflammation-neurobehavior performance links through developmental stages and intervention opportunities.

Impact of second-generation antipsychotics monotherapy or combined therapy in cytokine, lymphocyte subtype, and thyroid antibodies for schizophrenia: a retrospective study

BACKGROUND

Schizophrenia (SCZ) shares high clinical relevance with the immune system, and the potential interactions of psychopharmacological drugs with the immune system are still an overlooked area. Here, we aimed to identify whether the second-generation antipsychotics (SGA) monotherapy or combined therapy of SGA with other psychiatric medications influence the routine blood immunity biomarkers of patients with SCZ.

METHODS

Medical records of inpatients with SCZ from January 2019 to June 2023 were retrospectively screened from June 2023 to August 2023. The demographic data and peripheral levels of cytokines (IL-2, IL-4, IL-6, TNF-α, INF-γ, and IL-17 A), lymphocyte subtype proportions (CD3+, CD4+, CD8 + T-cell, and natural killer (NK) cells), and thyroid autoimmune antibodies (thyroid peroxidase antibody (TPOAb), and antithyroglobulin antibody (TGAb)) were collected and analyzed.

RESULTS

30 drug-naïve patients, 64 SGA monotherapy (20 for first-episode SCZ, 44 for recurrent SCZ) for at least one week, 39 combined therapies for recurrent SCZ (18 with antidepressant, 10 with benzodiazepine, and 11 with mood stabilizer) for at least two weeks, and 23 used to receive SGA monotherapy (had withdrawn for at least two weeks) were included despite specific medication. No difference in cytokines was found between the SGA monotherapy sub-groups (p > 0.05). Of note, SGA monotherapy appeared to induce a down-regulation of IFN-γ in both first (mean [95% confidence interval]: 1.08 [0.14-2.01] vs. 4.60 [2.11-7.08], p = 0.020) and recurrent (1.88 [0.71-3.05] vs. 4.60 [2.11-7.08], p = 0.027) episodes compared to drug-naïve patients. However, the lymphocyte proportions and thyroid autoimmune antibodies remained unchanged after at least two weeks of SGA monotherapy (p > 0.05). In combined therapy groups, results mainly resembled the SGA monotherapy for recurrent SCZ (p > 0.05).

CONCLUSION

The study demonstrated that SGA monotherapy possibly achieved its comfort role via modulating IFN-γ, and SGA combined therapy showed an overall resemblance to monotherapy.

Upregulated solute-carrier family genes in the hippocampus of schizophrenia can be rescued by antipsychotic medications

BACKGROUND AND HYPOTHESIS

Our previous studies have found that functional changes in the hippocampal circuit from dentate gyrus (DG) to cornu ammonis 3 and 1 (CA3, CA1) are highly associated with schizophrenia (SZ). However, no studies have explored the genetic expression across the three and two human hippocampal subfields (DG-CA3-CA1 and CA3-CA1) between subjects with SZ and healthy controls (CT).

STUDY DESIGN

We matched cohorts between CT (n = 13) and SZ (n = 13). Among SZ, 6 subjects were on antipsychotics (AP) while 7 were off AP. We combined RNA-seq data from all three and two hippocampal subfields and performed differentially expressed gene analyses across DG-CA3-CA1 and CA3-CA1 affected by either SZ or AP.

STUDY RESULTS

We found that differentially expressed genes (DEGs) from effects of SZ and AP across DG-CA3-CA1 and CA3-CA1 were highly associated with gene ontology terms related to hormonal and immune signaling, cellular mitosis and apoptosis, ion and amino acid transports, and protein modification and degradation. Additionally, we found that multiple genes related to solute-carrier family and immune signaling were significantly upregulated across DG-CA3-CA1 and CA3-CA1 in patients with SZ relative to CT, and AP consistently and robustly repressed the expression of these upregulated genes in the DG-CA3-CA1 and CA3-CA1 from subjects with SZ.

CONCLUSIONS

Together, these data suggest that the upregulated solute-carrier family genes in the hippocampus might have important roles in the pathophysiology of SZ, and that AP may reduce the symptoms of psychosis in SZ via rescuing the solute-carrier gene expression.

B Cell-activating factor (BAFF): A promising trans-nosographic biomarker of inflammation and autoimmunity in bipolar disorder and schizophrenia

Immune dysregulation is an important aspect of schizophrenia (SZ) and bipolar disorders (BD) pathophysiology, including not only inflammatory but also autoimmune process reflective of abnormal humoral immune responses. Given that B cell-activating factor (BAFF) is an integral aspect of B lymphocyte regulation, the current study investigated BAFF in SZ and BD. 255 SZ patients, 407 BD patients and 185 healthy controls (HC) were investigated across three aspects of soluble BAFF (sBAFF) by (i) comparing sBAFF circulatory levels across SZ, BD and HC, (ii) determining potential correlations between the circulating levels of sBAFF and the genotype distribution of a functionally relevant polymorphism, namely the TNFSF13B 3'UTR insertion-deletion polymorphism (GCTGT>A), (iii) analyzing relationships between both sBAFF levels and 3'UTR insertion-deletion genotypes and disease risk, patients clinical characteristics and circulating levels of potent inflammatory molecules. In addition, in subsets of patients, we also searched for possible correlations between sBAFF levels and stigma of past infectious events as well as positivity for circulating systemic autoantibodies or those directed against central nervous system (CNS) structures. Studying blood derived serum and DNA, weobserved that circulating sBAFF levels were significantly higher in SZ and BD patients, versus HC (p = 5.3*10-10and p = 4.4*10-09). Patients experiencing acute episodes, versus stable patients, in between acute episodes, exhibited higher sBAFF levels (p = 0.017).In SZ patients, positive correlations were observed between elevated sBAFF levels and: (i) elevated positive psychotic symptoms (PANSS pos), (ii) history of childhood trauma (physical abuse), and (iii) low scores on global functioning (GAF) (p = 0.024, p = 0.024, and p = 0.041).We also found that the distribution of the BAFF Ins/Del genotypes was significantly correlated with circulating sBAFF levels in SZ and BD patients (p = 0.0004). Elevated sBAFF levels were also correlated with increased levels of pro-inflammatory markers in both SZ and BD cohorts (p < 0.001). Regarding infectious stigma, only patients seropositive, versus seronegative, for herpes simplex virus (HSV)1 immunoglobulin (Ig)G antibodies exhibited a significant association with high sBAFF levels (p = 0.013). In contrast, positivity for systemic or CNS autoantibodies was significantly associated with reduced sBAFF levels, compared to patients without autoantibodies (p = 0.0017). Overall, our findings indicate that BAFF may be a promising trans-nosographic biomarker of inflammation that is likely to offer predictive, diagnostic, and prognostic tools for the management of SZ and BD. The results therefore have practicable clinical utility given the availability of immunotherapeutic treatment options including targeted monoclonal antibodies against BAFF.