Changes in serum TNF-α, IL-18, and IL-6 concentrations in patients with chronic schizophrenia at admission and at discharge

Inulin alleviates chronic ketamine-induced impairments in memory and prepulse inhibition by regulating the gut microbiota, inflammation, and kynurenine pathway

Chronic ketamine administration causes cognitive impairments similar to those observed in schizophrenia. Growing evidence suggests that patients with schizophrenia show alterations in gut microbiota, which is associated with cognitive impairments. Inulin could regulate gut microbiota. However, it is unclear whether chronic ketamine exposure causes cognitive impairments by mediating gut microbiota and whether inulin ameliorates these impairments. In this study, we found that chronic ketamine exposure for 14 days induced gut dysbiosis, thereby increasing gut permeability, upregulating LPS-activated TLR4-NF-κB-NLRP3 inflammatory pathway, causing hippocampal neuroinflammation and neuronal damage, activating tryptophan (TRP)-kynurenine (KYN)-kynurenic acid (KYNA) pathway in the hippocampus, peripheral serum, and feces, and thus leading to deficits in recognition memory and prepulse inhibition (PPI). In addition, inulin treatment restored gut dysbiosis by increasing the abundance of Turicibacter and Ileibacterium and decreasing the abundance of Alistipes, Alloprevotella, Desulfovibrio, and Parasutterella, which may improve gut barrier damage by upregulating tight junction protein expression, suppress LPS-mediated TLR4-NF-κB-NLRP3 inflammatory pathway to reduce neuroinflammation and neuronal damage, inhibit TRP-KYN-KYNA metabolism pathway, and thus alleviate chronic ketamine-associated impairments in PPI and memory. Our findings provide additional evidence that inulin treatment is a potential intervention strategy for treating chronic ketamine-associated cognitive impairments and cognitive deficits in schizophrenia.

Effect of Long-Term Tai Chi Therapy on the Immune-Inflammatory Pathway in Patients with Schizophrenia with Antipsychotic-Stabilized

The primary objective of this study was to explore the influence of prolonged (24 weeks) supplementary Tai Chi therapy on cognitive capabilities and immune-inflammatory pathways in subjects diagnosed with schizophrenia. A total of 90 individuals who have been clinically diagnosed with schizophrenia were assigned to two treatment groups, namely the Tai Chi treatment (TT) group and the routine treatment (RT) group. Following a 24-week duration of intervention, the data obtained from 32 patients in the TT group and 30 patients in the RT group were meticulously analyzed. At the commencement of the investigation and upon completion of the 24-week intervention, blood samples were gathered, and clinical evaluations were executed. In plasma, the identification of nine cytokines (IL-10, IFN-γ, IL-5, GM-CSF, TNF-α, IL-13, IL-4, IL-2, and IL-12) was conducted using the multiple primer suspension chip method. The clinical evaluations encompassed CGI, WHOQUOL-BREF, SOFS, PSS, BPRS, SAPS, SANS, and RBANS. In comparison to the RT group, the patients in the TT group demonstrated decreased levels of TNF-α and IL-5 (P < 0.05). Moreover, they encountered more pronounced advancements in SAPS, SANS, PSS, SOFS, and RBANS scores (P < 0.05). Additionally, a positive connection was detected between the plasma TNF-α level in the TT group and both the SANS score and the SPFS score (P < 0.05). Tai Chi has been shown to improve clinical symptoms in patients with schizophrenia as an add-on therapy, potentially through its effects on immunomodulatory pathways.

Psychosis of Epilepsy: An Update on Clinical Classification and Mechanism

Epilepsy is a prevalent chronic neurological disorder that can significantly impact patients' lives. The incidence and risk of psychosis in individuals with epilepsy are notably higher than in the general population, adversely affecting both the management and rehabilitation of epilepsy and further diminishing patients' quality of life. This review provides an overview of the classification and clinical features of psychosis of epilepsy, with the aim of offering insights and references for the clinical diagnosis and treatment of various types of psychosis of epilepsy. Additionally, we examine the potential pathophysiological mechanisms underlying the psychosis of epilepsy from three perspectives: neuroimaging, neurobiology, and genetics. The alterations in brain structure and function, neurotransmitters, neuroinflammatory mediators, and genetic factors discussed in this review may offer insights into the onset and progression of psychotic symptoms in epilepsy patients and are anticipated to inform the identification of novel therapeutic targets in the future.

Psychotic relapse prediction via biomarker monitoring: a systematic review

Background

Associating temporal variation of biomarkers with the onset of psychotic relapse could help demystify the pathogenesis of psychosis as a pathological brain state, while allowing for timely intervention, thus ameliorating clinical outcome. In this systematic review, we evaluated the predictive accuracy of a broad spectrum of biomarkers for psychotic relapse. We also underline methodological concerns, focusing on the value of prospective studies for relapse onset estimation.

Methods

Following the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines, a list of search strings related to biomarkers and relapse was assimilated and run against the PubMed and Scopus databases, yielding a total of 808 unique records. After exclusion of studies related to the distinction of patients from controls or treatment effects, the 42 remaining studies were divided into 5 groups, based on the type of biomarker used as a predictor: the genetic biomarker subgroup (n = 4, or 9%), the blood-based biomarker subgroup (n = 15, or 36%), the neuroimaging biomarker subgroup (n = 10, or 24%), the cognitive-behavioral biomarker subgroup (n = 5, or 12%) and the wearables biomarker subgroup (n = 8, or 19%).

Results

In the first 4 groups, several factors were found to correlate with the state of relapse, such as the genetic risk profile, Interleukin-6, Vitamin D or panels consisting of multiple markers (blood-based), ventricular volume, grey matter volume in the right hippocampus, various functional connectivity metrics (neuroimaging), working memory and executive function (cognition). In the wearables group, machine learning models were trained based on features such as heart rate, acceleration, and geolocation, which were measured continuously. While the achieved predictive accuracy differed compared to chance, its power was moderate (max reported AUC = 0.77).

Discussion

The first 4 groups revealed risk factors, but cross-sectional designs or sparse sampling in prospective studies did not allow for relapse onset estimations. Studies involving wearables provide more concrete predictions of relapse but utilized markers such as geolocation do not advance pathophysiological understanding. A combination of the two approaches is warranted to fully understand and predict relapse.

Expression pattern of long non-coding RNAs in treatment-naïve and medicated schizophrenia patients

Schizophrenia is a disabling mental disorder that affects 1% of people over their lifetime. The etiology and mechanism of schizophrenia are very complex, and many genes are involved in many different signaling pathways in the etiology of this disease. According to recent studies, one of the important mechanisms altered in this disorder is the regulation of immune system and the inflammation mechanism. In the present study, we evaluated the peripheral blood expression pattern of four lncRNAs and three protein-coding genes in the treatment- naïve patients, and medicated patients compared with sex and age-matched controls. In the medicated-patients, expression levels of IFNG, IL18RAP, AC007278.2 were significantly up-regulated (P < 0.05); and the expression level of IFNG-AS1-001 was significantly down-regulated compared to healthy controls (P < 0.05). However, levels of IL18R1, AC007278.3 and IFNG-AS1-003 were not different between these groups. In the treatment-naïve patients, IFNG, IL18R1, IL18RAP, IFNG-AS1-001, AC007278.2, and AC007278.3 were significantly up-regulated compared to controls. On the other hand, IFNG-AS1-003 was significantly down-regulated in the treatment-naïve patients compared to controls. Based on the Spearman correlation matrix, there was a significant correlation between genes in the treatment-naïve patients. We also showed the high sensitivity and specificity of IFNG-AS1-003, IFNG, IL18R1, and AC007278.3 in the identification of treatment-naïve patients from controls. The current study contributes further evidence to the understanding of the role of lncRNAs in the pathogenesis of schizophrenia. Future research is necessary to establish the validity of lncRNAs as peripheral markers for this condition.

Exploring the role of TNF-α, TGF-β, and IL-6 serum levels in categorical and noncategorical models of mood and psychosis

Psychotic and mood disorders are discussed as part of the same continuum. The potential role of immune dysregulation in defining their clinical presentations, however, remains unclear. Differences in TNF-α, IL-6 and TGF-β levels were investigated in 143 patients with schizophrenia (SCH = 63) and bipolar disorder (BD = 80), in remission. Cytokines were evaluated against the dimensional assessment of psychosis and affective symptoms using the schizo-bipolar scale, together with the severity of the same symptom domains measured by the brief psychiatric rating scale (BPRS). Lower TGF-β was associated with more lifetime episodes, family risk for psychosis, and more severe mood and psychotic symptoms in all patients. BPRS Affect symptoms domain correlated with lower TGF-β levels in BD, and higher TGF-β levels in SCH patients. Using moderated mediation analysis, TGF-β was a relevant predictor only in the setting of non-categorical symptom distribution, with familial risk for psychosis confirmed as a significant moderator. Severity of BPRS Affect symptoms domain was an independent predictor of inclination towards the psychosis spectrum. The underlying immune dysregulation may be shared by the disorders, rather than a unique characteristic of each, having significant implications for our understanding of the continuum vs. categorical approach to psychosis and mood disorders.

Navigating the Neuroimmunomodulation Frontier: Pioneering Approaches and Promising Horizons-A Comprehensive Review

The research in neuroimmunomodulation aims to shed light on the complex relationships that exist between the immune and neurological systems and how they affect the human body. This multidisciplinary field focuses on the way immune responses are influenced by brain activity and how neural function is impacted by immunological signaling. This provides important insights into a range of medical disorders. Targeting both brain and immunological pathways, neuroimmunomodulatory approaches are used in clinical pain management to address chronic pain. Pharmacological therapies aim to modulate neuroimmune interactions and reduce inflammation. Furthermore, bioelectronic techniques like vagus nerve stimulation offer non-invasive control of these systems, while neuromodulation techniques like transcranial magnetic stimulation modify immunological and neuronal responses to reduce pain. Within the context of aging, neuroimmunomodulation analyzes the ways in which immunological and neurological alterations brought on by aging contribute to cognitive decline and neurodegenerative illnesses. Restoring neuroimmune homeostasis through strategies shows promise in reducing age-related cognitive decline. Research into mood disorders focuses on how immunological dysregulation relates to illnesses including anxiety and depression. Immune system fluctuations are increasingly recognized for their impact on brain function, leading to novel treatments that target these interactions. This review emphasizes how interdisciplinary cooperation and continuous research are necessary to better understand the complex relationship between the neurological and immune systems.

TLR4 Polymorphisms (T399I/D299G) Association with Schizophrenia and Bipolar Disorder in a Tunisian Population

Immune dysregulation has been widely described in the pathophysiology of schizophrenia (SCZ) and bipolar disorder (BD). Particularly, TLR4-altered activation was proposed as one of the underlying processes of psychosis onset. Since TLR4 activation was altered by T399I and D299G polymorphisms, we hypothesized that those variants could present common genetic factors of SCZ and BD. A total of 293 healthy volunteers and 335 psychotic patients were genotyped using PCR-RFLP. Genotype, allele, and haplotype distribution between controls and patients were evaluated according to clinical parameters. Statistical analyses were adjusted by logistic regression. In dominant model, T399I CT + TT and allele frequency were significantly higher in controls compared to psychotic population (p = 0.004, p = 0.002, respectively), SCZ (p = 0.02, p = 0.01, respectively), and BD (p = 0.03, p = 0.02, respectively). Similarly, D299G AG + GG and allele frequency were significantly higher in controls compared to psychotic population (p = 0.04, p = 0.04, respectively) and SCZ (p = 0.04, p = 0.03, respectively). T399I CT + TT and T allele were overrepresented in controls compared to paranoid subgroup (Padjusted = 0.04, p = 0.04, respectively) and type I BD (p = 0.04). Moreover, T399I and D299G were less prevalent in SCZ late-onset age (p = 0.03, p = 0.02, respectively). TA haplotype was associated with protection from psychoses (p = 0.02) and particularly from schizophrenia (p = 0.04). In conclusion, TLR4 polymorphisms could present a preventive genetic background against psychoses onset in a Tunisian population. While T399I could be associated with protection against SCZ and BD, presenting an overlapping genetic factor between those psychoses, D299G was suggested to be associated with protection only from schizophrenia.

Association of serum interleukin-6 with negative symptoms in stable early-onset schizophrenia

BACKGROUND

Accumulating evidence suggests that the inflammatory cytokine interleukin-6 (IL-6) contributes to the pathophysiology of psychiatric disorders. However, there was no study concerning the relationship between IL-6 concentrations and clinical features in the chronic phase of early-onset schizophrenia (EOS).

AIM

To investigate the relationship between serum IL-6 concentration and the clinical features of EOS.

METHODS

We measured serum IL-6 Levels from 74 patients with chronic schizophrenia, including 33 with age at onset < 21 years (EOS group) and 41 with onset ≥ 21 years in [adult-onset schizophrenia (AOS) group], and from 41 healthy controls. Symptom severities were evaluated using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Serum IL-6 concentrations were higher in both EOS and AOS groups than healthy controls (F = 22.32, P < 0.01), but did not differ significantly between EOS and AOS groups (P > 0.05) after controlling for age, body mass index, and other covariates. Negative symptom scores were higher in the EOS group than the AOS group (F = 6.199, P = 0.015). Serum IL-6 concentrations in the EOS group were negatively correlated with both total PANSS-negative symptom score (r = -0.389, P = 0.032) and avolition/asociality subscore (r = -0.387, P = 0.026).

CONCLUSION

Patients with EOS may have more severe negative symptoms than those with adult-onset schizophrenia during the chronic phase of the illness. IL-6 signaling may regulate negative symptoms and its avolition/asociality subsymptoms among the early-onset chronic schizophrenic patients.

Effects of IL-6/IL-6R axis alterations in serum, plasma and cerebrospinal fluid with the schizophrenia: an updated review and meta-analysis of 58 studies

Studies investigating the association between IL-6/IL-6R axis and schizophrenia (SZ) susceptibility found inconsistent data. To reconcile the results, a systematic review followed by a meta-analysis was performed to assess the associations. This study followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A comprehensive search of the literature was carried out in July 2022 using electronic databases PubMed, EBSCO, Science Direct, PsychInfo, and Scopus. Study quality was assessed by the Newcastle-Ottawa scale. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by fixed-effect or random-effect model analysis. Fifty-eight studies were identified, including 4,200 SZ patients and 4,531 controls. Our meta-analysis results showed an increase of IL-6 levels in plasma, serum, or CSF and decreased IL-6R levels in serum in patients under treatment. Further studies are needed to better elucidate the correlation between the IL-6/IL-6R axis and the schizophrenia.

Association between elevated serum matrix metalloproteinase-2 and tumor necrosis factor-α, and clinical symptoms in male patients with treatment-resistant and chronic medicated schizophrenia

BACKGROUND

Inflammation has an important role in the pathogenesis of schizophrenia. The aim of this study was to investigate the levels of tumor necrosis factor (TNF) and matrix metalloproteinase-2 (MMP-2) in male patients with treatment-resistant schizophrenia (TRS) and chronic medicated schizophrenia (CMS), and the relationship with psychopathology.

METHODS

The study enrolled 31 TRS and 49 cm male patients, and 53 healthy controls. Serum MMP-2 and TNF-α levels were measured by the Luminex liquid suspension chip detection method. Positive and Negative Syndrome Scale (PANSS) scores were used to evaluate symptom severity and Repeatable Battery for the Assessment of Neuropsychological Status was used to assess cognitive function.

RESULTS

Serum TNF-α and MMP-2 levels differed significantly between TRS, CMS and healthy control patients (F = 4.289, P = 0.016; F = 4.682, P = 0.011, respectively). Bonferroni correction demonstrated that serum TNF-α levels were significantly elevated in CMS patients (P = 0.022) and MMP-2 levels were significantly higher in TRS patients (P = 0.014) compared to healthy controls. In TRS patients, TNF-α was negatively correlated with age (r=-0.435, P = 0.015) and age of onset (r=-0.409, P = 0.022). In CMS patients, MMP-2 and TNF-α were negatively correlated with PANSS negative and total scores, and TNF-α was negatively correlated with PANSS general psychopathology scores (all P < 0.05). MMP-2 levels were positively correlated with TNF-α levels (P < 0.05), but not with cognitive function (P > 0.05).

CONCLUSION

The results indicate the involvement of inflammation in the etiology of TRS and CMS. Further studies are warranted.

Association between cognitive function and IL-18 levels in schizophrenia: Dependent on IL18 - 607 A/C polymorphism

Accumulating evidence suggests that immune system dysregulation is associated with debilitating neurodevelopment in schizophrenia (SZ). Cognitive impairment is a persistent feature that occurs during the onset of SZ and persists throughout the course of the disease. Early studies have found that elevated interleukin (IL)- 18 interacts with IL18 polymorphism and is correlated with psychotic symptoms in SZ. This study aimed to investigate whether elevated IL-18 levels interacted with the -607 A/C polymorphism to determine cognitive decline in patients with chronic SZ. We recruited 693 inpatients and 422 healthy controls to measure IL-18 levels and genotype the - 607 A/C polymorphism. Further, cognitive function was measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). We found that IL-18 serum levels were higher in patients than those in healthy controls, and were not associated with IL18 - 607 A/C in combined subjects or either patients or healthy controls, respectively. Moreover, - 607 A/C was correlated with the visuospatial/constructional index only in the patients. In addition, our research found that IL-18 levels were positively correlated to immediate memory only in patients with the C/C genotype, but not in patients with C/A or A/A genotype. This study suggests that the relationship of IL-18 with cognitive function depends on the IL18 - 607 A/C polymorphism of SZ patients.

Is there any association between cognitive deficits and immune markers in Acute and Transient psychotic disorders? A pilot study

BACKGROUND

There are studies to support association between immune function and cognition in patients with schizophrenia (SZ). However, there are no such study which had tried to explore the same in patients with Acute and transient psychotic disorders (ATPDs), which is considered to similar in presentation to SZ.

METHODS

This is an extended analysis of the study published in which we had recruited 19 subjects with ATPDs in acute phase of illness were age-/gender-matched with patients schizophrenia in remission. Clinical assessment and immune-marker levels (IL-6,IL-8,IL-17) were carried out along with follow -up repeat immune-marker levels assessment in the ATPD group was conducted after remission status was ensured (at least 3 months after resolution of acute phase). Cognitive assessment was done on Montreal Cognitive Assessment Scale (MoCA) in both the groups (ATPD in both phases and in SZ).

RESULTS

The mean MoCA total score was 12.05 (SD-5.0) in the acute phase and 27.05 (SD-2.46) in the remission phase in the ATPD group which was statistically significant. When compared with patients with SZ in remission, patients with ATPD in remission performed better in all domains of MoCA, however only statistically significant differences in the total MoCA score and in the visuospatial domain scores of MoCA. No significant association between any of the immune marker levels (IL-6, Il-8 and IL-17) with any domains of the MoCA in patients with ATPD neither in the acute phase nor in the remission phase was found. Additionally, no significant association between the cognitive scores in the MoCA domains of the patients with schizophrenia and immune marker levels was found too.

CONCLUSION

To conclude, the present study's findings suggested that there existed definite cognitive deficits in patients with ATPDs in both acute and remission phase and in patients with SZ. However, the study could not establish any relationship/association between cognitive deficits/scores in patients with ATPDs in both phases as well as in patients with SZ with immune marker levels.

Changes in cytokine and cytokine receptor levels during postnatal development of the human dorsolateral prefrontal cortex

In addition to their traditional roles in immune cell communication, cytokines regulate brain development. Cytokines are known to influence neural cell generation, differentiation, maturation, and survival. However, most work on the role of cytokines in brain development investigates rodents or focuses on prenatal events. Here, we investigate how mRNA and protein levels of key cytokines and cytokine receptors change during postnatal development of the human prefrontal cortex. We find that most cytokine transcripts investigated (IL1B, IL18, IL6, TNF, IL13) are lowest at birth and increase between 1.5 and 5 years old. After 5 years old, transcriptional patterns proceeded in one of two directions: decreased expression in teens and young adults (IL1B, p = 0.002; and IL18, p = 0.004) or increased mean expression with maturation, particularly in teenagers (IL6, p = 0.004; TNF, p = 0.002; IL13, p < 0.001). In contrast, cytokine proteins tended to remain elevated after peaking significantly around 3 years of age (IL1B, p = 0.012; IL18, p = 0.026; IL6, p = 0.039; TNF, p < 0.001), with TNF protein being highest in teenagers. An mRNA-only analysis of cytokine receptor transcripts found that early developmental increases in cytokines were paralleled by increases in their ligand-binding receptor subunits, such as IL1R1 (p = 0.033) and IL6R (p < 0.001) transcripts. In contrast, cytokine receptor-associated signaling subunits, IL1RAP and IL6ST, did not change significantly between age groups. Of the two TNF receptors, the 'pro-death' TNFRSF1A and 'pro-survival' TNFRSF1B, only TNFRSF1B was significantly changed (p = 0.028), increasing first in toddlers and again in young adults. Finally, the cytokine inhibitor, IL13, was elevated first in toddlers (p = 0.006) and again in young adults (p = 0.053). While the mean expression of interleukin-1 receptor antagonist (IL1RN) was highest in toddlers, this increase was not statistically significant. The fluctuations in cytokine expression reported here support a role for increases in specific cytokines at two different stages of human cortical development. The first is during the toddler/preschool period (IL1B, IL18, and IL13), and the other occurs at adolescence/young adult maturation (IL6, TNF and IL13).

Immunological protein profiling of first-episode psychosis patients identifies CSF and blood biomarkers correlating with disease severity

BACKGROUND AND HYPOTHESIS

Immune activation is suggested to play an important role in psychosis. In this study, a large number of immune-related proteins were analyzed to obtain a more comprehensive picture of immune aberrations in schizophrenia.

STUDY DESIGN

Ninety-two immune markers were analyzed by the Olink Protein Extension Assay (Inflammatory Panel) in plasma and cerebrospinal fluid (CSF) from 77 first-episode psychosis (FEP) patients (of which 43 later received the diagnosis of schizophrenia) and 56 healthy controls, all recruited from the Karolinska Schizophrenia Project (KaSP), Stockholm, Sweden.

STUDY RESULTS

Differential analysis showed that 12 of 92 inflammatory proteins were significantly higher in the plasma of FEP patients (n = 77) than in controls, and several proteins were positively correlated with disease severity. Patients from the same cohort diagnosed with schizophrenia (n = 43), showed significantly higher levels of 15 plasma proteins compared to controls whereas those not receiving this diagnosis showed no significant differences. The presently used OLINK inflammatory panel allowed the detection of only 47 CSF proteins of which only CD5 differed between patients and controls.

CONCLUSIONS

The levels of several peripheral immune markers, particularly those interfering with WNT/β-catenin signaling, were significantly higher in patients with FEP than in healthy controls and associated with illness severity.

Sex differences in the association of treatment-resistant schizophrenia and serum interleukin-6 levels

BACKGROUND

Low-grade inflammation and altered inflammatory markers have been observed in treatment-resistant schizophrenia (TRS). Interleukin-6 (IL-6) is one of the pro-inflammatory cytokines linked with TRS and receives increasing attention. Previous studies showed that patients with TRS might have higher IL-6 levels compared with healthy individuals and treatment-responsive patients. Besides, emerging evidence has suggested that there are sex differences in the associations between IL-6 levels and various illnesses, including chronic hepatitis C, metabolic syndrome, etc.; however, there is limited study on TRS. In this present study, we aimed to compare the serum IL-6 levels of TRS and partially responsive schizophrenia (PRS) and explore potential sex differences in the association of TRS and IL-6 levels.

METHODS

The study population consisted of a total of 90 patients with schizophrenia: 64 TRS patients (45.3% males and 54.7% females) and 26 PRS patients (46.2% males and 53.8% females). We measured serum IL-6 levels using enzyme-linked immunosorbent assay (ELISA) and analyzed them separately by gender, controlling for confounders (age, education, medication, body mass index, and PANSS scores) rigorously.

RESULT

The results showed that patients with TRS had higher serum IL-6 levels than patients with PRS (p = 0.002). In females, IL-6 levels increased significantly in the TRS group compared with the PRS group (p = 0.005). And a positive correlation tendency was observed between IL-6 levels and PANSS general sub-scores (r = 0.31, p = 0.039), although this correlation was not significant after correcting for multiple comparisons. Whereas, there were no differences in IL-6 levels between the TRS and PRS (p = 0.124) in males.

CONCLUSION

Our findings provided evidence supporting the hypothesis that the inflammatory response system (IRS) may play a role in the pathogenesis of TRS in a sex-dependent manner. In addition, sex differences in the immune dysfunction of individuals with schizophrenia cannot be neglected, and inflammation in male and female TRS should be discussed separately.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Anti-inflammatory effects of 2nd generation antipsychotics in patients with schizophrenia: A systematic review and meta-analysis

BACKGROUND

Schizophrenia is a major psychiatric disorder with unknown aetiology. Recent evidence suggests a potential role for cytokines in its pathophysiology and that antipsychotic medication may alter this. While the aetiology of schizophrenia remains only partly understood, an altered immune function representing an important avenue of further discovery. In this systematic review and meta-analysis we focus on the specific effects of second generation antipsychotics risperidone and clozapine on inflammatory cytokines.

METHODS

A defined systematic search of PubMed and Web of Science databases was performed to identify relevant studies published between Jan 1900 and May 2022. After screening of 2969 papers, 43 studies (27 single-arm and 8 dual-arm) were included that consisted of a total of 1421 patients with schizophrenia in the systematic review. From these, twenty studies (4 dual-arm; 678 patients) had data available on which a meta-analysis could be carried out.

RESULTS

Our meta-analysis showed a significant reduction of pro-inflammatory cytokines post-risperidone treatment in the absence of a similar association with clozapine. Subgroup analyses (First episode v chronic) demonstrated that duration of illness influenced the extent of cytokine alteration; risperidone treatment produced significant cytokine changes (lowered IL-6 and TNF-α) in chronic patients but not in first-episode psychosis (FEP) patients.

CONCLUSION

Varying treatment effects on cytokines can be observed by the use of different antipsychotic drugs. The cytokine alterations post-treatment are influenced by the specific antipsychotic drugs and patient status. This may explain disease progression in certain patient groups and influence therapeutic choices in the future.

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

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

Depression trajectories and cytokines in schizophrenia spectrum disorders - A longitudinal observational study

Depression occurs frequently in all phases of schizophrenia spectrum disorders. Altered activity in the immune system is seen in both depression and schizophrenia. We aimed to uncover depressive trajectories in a sample of 144 adult individuals with schizophrenia spectrum disorders followed for one year, in order to identify possible cytokine profile differences. Patients were assessed longitudinally with the Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS), where a score above 6 predicts depression. The serum cytokine concentrations for tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10, IL-12p70 and IL-17A were measured using immunoassays. Latent growth curve models, multilevel models and latent class growth analysis (LCGA) were applied. The LCGA model supported three latent classes (trajectories) with differing CDSS profiles during the one-year follow-up: a high CDSS group (40.8 % of participants), a moderate CDSS group (43.9 %) and a low CDSS group (15.3 %). Five single PANSS items predicted affiliation to depressive trajectory: hallucinations, difficulty in abstract thinking, anxiety, guilt feelings and tension. In the high CDSS group, despite diminishing psychotic symptoms, depressive symptoms persisted throughout one year. The pro-inflammatory cytokines IFN-γ, IL-1β and TNF-α were differentially distributed between the depressive trajectories, although levels remained remarkably stable throughout 12 months. Significant changes were found for the anti-inflammatory cytokine IL-10 at baseline with an accompanying difference in change over time. More research is required to optimize future treatment stratification and investigate the contribution of inflammation in depressed patients with schizophrenia spectrum disorders.

Inflammation and Mental Health Disorders: Immunomodulation as a Potential Therapy for Psychiatric Conditions

Mood disorders are the leading cause of disability worldwide and their incidence has significantly increased after the COVID-19 pandemic. Despite the continuous surge in the number of people diagnosed with psychiatric disorders, the treatment methods for these conditions remain limited. A significant number of people either do not respond to therapy or discontinue the drugs due to their severe side effects. Therefore, alternative therapeutic interventions are needed. Previous studies have shown a correlation between immunological alterations and the occurrence of mental health disorders, yet immunomodulatory therapies have been barely investigated for combating psychiatric conditions. In this article, we have reviewed the immunological alterations that occur during the onset of mental health disorders, including microglial activation, an increased number of circulating innate immune cells, reduced activity of natural killer cells, altered T cell morphology and functionality, and an increased secretion of pro-inflammatory cytokines. This article also examines key studies that demonstrate the therapeutic efficacy of anti-inflammatory medications in mental health disorders. These studies suggest that immunomodulation can potentially be used as a complementary therapy for controlling psychiatric conditions after careful screening of candidate drugs and consideration of their efficacy and side effects in clinical trials.

A Causal-Pathway Phenotype of Chronic Fatigue Syndrome due to Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

End-stage renal disease (ESRD) is associated with fatigue and physiosomatic symptoms.

OBJECTIVE

The objective of this study is to delineate the associations between severity of fatigue and physio-somatic symptoms and glomerular filtration rate, inflammatory biomarkers, and Wnt/cateninpathway proteins.

METHODS

The Wnt-pathway related proteins β-catenin, Dickkopf-related protein 1 (DKK1), R-spondin- 1, and sclerostin were measured by ELISA technique in 60 ESRD patients and 30 controls. The Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale was used to assess the severity of FF symptoms.

RESULTS

ESRD is characterized by a significant increase in the total FF score, muscle tension, fatigue, sadness, sleep disorders, gastro-intestinal (GI) symptoms, and a flu-like malaise. The total-FF score was significantly correlated with serum levels of urea, creatinine, and copper (positively), and β-catenin, eGFR, hemoglobin, albumin, and zinc (inversely). The total-FF score was associated with the number of total dialysis and weekly dialysis sessions, and these dialysis characteristics were more important in predicting FF scores than eGFR measurements. Partial Least Squares analysis showed that the FF score comprised two factors that are differently associated with biomarkers: a) 43.0% of the variance in fatigue, GI symptoms, muscle tension, sadness, and insomnia is explained by hemoglobin, albumin, zinc, β-catenin, and R-spondin-1; and b) 22.3% of the variance in irritability, concentration and memory impairments by increased copper and cations/chloride ratio, and male sex.

CONCLUSION

ESRD patients show high levels of fatigue and physio-somatic symptoms associated with hemodialysis and mediated by dialysis-induced changes in inflammatory pathways, the Wnt/catenin pathway, and copper.

Mendelian randomization study on the effect of tumor necrosis factor on schizophrenia

OBJECTIVE

Previous observational studies have shown that the levels of tumor necrosis factor (TNF) increased in patients with schizophrenia. The present two-sample Mendelian randomization (MR) study aims to identify the causal link between TNF and schizophrenia.

METHODS

To date, the largest genome-wide association study (GWAS) for TNF (n = 23 141) and for schizophrenia (53 386 cases and 77 258 controls) was used. All participants were of European ancestry. The MR-egger_intercept test and Cochran's Q statistic were used to determine the pleiotropy and heterogeneity, respectively. Weighted median and inverse variance weighted (IVW) were used to evaluate the causal association of TNF with schizophrenia.

RESULTS

We found no significant pleiotropy or heterogeneity of all three selected plasma TNF genetic instrumental variants in breast cancer GWAS. Interestingly, the odds ratio (OR) = 1.517 with 95% confidence interval (CI), 1.006-2.288 and P = 0.047 of schizophrenia correspond to one unit increase in natural log-transformed TNF levels using IVW method. The increased trend was further proven using weighted median (OR = 1.585; 95% CI, 1.017-2.469; P = 0.042). Reverse MR analysis shows no causal effect of schizophrenia on plasma TNF levels.

CONCLUSIONS

Our analysis suggested a causal association between genetically increased TNF signaling and increased risk of schizophrenia in the European population. Thus, TNF may be a potential risk for schizophrenia.

Cytokines as Potential Biomarkers of Clinical Characteristics of Schizophrenia

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

Cytokine Imbalance as a Biomarker of Treatment-Resistant Schizophrenia

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

Predictive Significance of High-Sensitivity C-Reactive Protein Combined with Homocysteine for Coronary Heart Disease in Patients with Anxiety Disorders

Background

Currently, there are few studies on biomarkers for predicting coronary heart disease (CHD) with anxiety disorders.

Objective

To explore risk factors and investigate the predictive value of common clinical peripheral blood indicators, such as high-sensitivity C-reactive protein (hs-CRP) and homocysteine (Hcy) for CHD patients with anxiety disorders.

Methods

One hundred fifty-three hospitalized patients with chest pain as the main symptom and a Hamilton Anxiety Scale score > 14 were recruited from October 2020 to September 2021 in the hospital. Then, they were divided into an anxiety disorder with CHD group (observation group, n = 64) and a simple anxiety disorder group (control group, n = 89), according to coronary angiography (CAG) findings. Patients' demographic and clinical messages were collected and compared. Diabetes mellitus and hypertension, body mass index (BMI), and peripheral blood interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), fibrinogen, D-dimer, cortisol, and norepinephrine expression levels were compared. Binary logistic regression analysis screened independent risk factors of CHD patients with anxiety disorders. The effectiveness of independent risk factors in predicting CHD with anxiety disorders was analyzed using receiver operating characteristic (ROC) curves.

Results

IL-6, hs-CRP, and Hcy levels of anxiety disorder in the CHD group were significantly higher than those in the simple anxiety disorder group. Binary multiple logistic regression analysis indicated that IL-6, hs-CRP, and Hcy were independent risk factors for CHD in patients with anxiety disorders. hs-CRP and Hcy levels were positively correlated with the Gensini score. ROC curve analysis indicated that the detection of hs-CRP or Hcy alone or the combined detection of the 2 had clinical predictive value for CHD in patients with anxiety disorders, and the area under the curve (AUC) of the combined detection of the 2 was significantly larger than that of any single factor alone (vs. hs-CRP, P = 0.045; vs. Hcy, P = 0.045).

Conclusion

IL-6, hs-CRP, and Hcy are related to CHD with anxiety disorders. Serum levels of the combined detection of hs-CRP and Hcy have a high clinical predictive value for CHD in patients with anxiety disorders.

Increased NLRP3 inflammasome expression in peripheral blood mononuclear cells of patients with schizophrenia: a case-control study

OBJECTIVE

This study aimed to evaluate the gene expression of the P2X purinoceptor 7 (P2X7R)- nod-like receptor pyrin domain-containing protein 3 (NLRP3) signal pathway in peripheral blood mononuclear cells (PBMCs) between schizophrenia (SCZ) patients and healthy controls (HC) to reveal its relationship with clinical variables.

METHODS

Thirty-two SCZ patients and 41 healthy controls were included in this study. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), The Global Assessment of Functioning (GAF) scale and the Functioning Assessment Short Test (FAST) scales were applied. P2X7R, NLRP3, IL-1β and IL-18 gene expression levels were evaluated by real-time polymerase chain reaction in PBMCs.

RESULTS

NLRP3, P2RX7, IL-1β and IL-18 expression levels were significantly higher in PBMCs of SCZ patients than in HC subjects. Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores. There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores and a positive correlation with the SAPS scale scores.

CONCLUSIONS

Systemic inflammation is implicated in SCZ pathogenesis, according to our findings, which suggest that the NLRP3 pathway may be involved. The NLRP3 inflammasome may serve as a biomarker for SCZ, and its pharmacological regulation may be a promising treatment approach.Key pointsWe hypothesised that the NLRP3 pathway may contribute to the etiopathogenesis of schizophrenia.NLRP3, IL-1β and IL-18 mRNA levels were higher in patients with schizophrenia compared to healthy controls.Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores.There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores.The SAPS scale scores and IL-18 expression levels had a positive correlation.Given all these findings, it can be stated that NLRP3 inflammasome may play a role in the pathogenesis and symptoms of schizophrenia.

Differential effects of lipopolysaccharide on cognition, corticosterone and cytokines in socially-housed vs isolated male rats

Social isolation is an established risk factor for mental illness and impaired immune function. Evidence suggests that neuroinflammatory processes contribute to mental illness, possibly via cytokine-induced modulation of neural activity. We examined the effects of lipopolysaccharide (LPS) administration and social home cage environment on cognitive performance in the 5-Choice Serial Reaction Time Task (5CSRTT), and their effects on corticosterone and cytokines in serum and brain tissue. Male Long-Evans rats were reared in pairs or in isolation before training on the 5CSRTT. The effects of saline and LPS (150 µg/kg i.p.) administration on sickness behaviour and task performance were then assessed. LPS-induced sickness behaviour was augmented in socially-isolated rats, translating to increased omissions and slower response times in the 5CSRTT. Both social isolation and LPS administration reduced impulsive responding, while discriminative accuracy remained unaffected. With the exception of reduced impulsivity in isolated rats, these effects were not observed following a second administration of LPS, revealing behavioural tolerance to repeated LPS injections. In a separate cohort of animals, social isolation potentiated the ability of LPS to increase serum corticosterone and IL-6, which corresponded to increased IL-6 in the orbitofrontal and medial prefrontal cortices and the nucleus accumbens. Basal IL-4 levels in the nucleus accumbens were reduced in socially-isolated rats. These findings are consistent with the adaptive response of reduced motivational drive following immune challenge, and identify social isolation as an exacerbating factor. Enhanced IL-6 signalling may play a role in mediating the potentiated behavioural response to LPS administration in isolated animals.

Limited association between infections, autoimmune disease and genetic risk and immune activation in severe mental disorders

BACKGROUND

Low-grade inflammation may be part of the underlying mechanism of schizophrenia and bipolar disorder. We investigated if genetic susceptibility, infections or autoimmunity could explain the immune activation.

METHODS

Seven immune markers were selected based on indicated associations to severe mental disorders (IL-1Ra, sIL-2R, IL-18, sgp130, sTNFR-1, APRIL, ICAM-1) and measured in plasma of patients with schizophrenia (SCZ, N = 732) and bipolar spectrum disorders (BD, N = 460) and healthy controls (HC, N = 938). Information on rate of infections and autoimmune diseases were obtained from Norwegian national health registries for a twelve-year period. Polygenic risk scores (PRS) of SCZ and BD were calculated from genome-wide association studies. Analysis of covariance were used to test effects of infection rate, autoimmune disease and PRS on differences in immune markers between patients and HC.

RESULTS

Infection rate differed between all groups (BD > HC > SCZ, all p < 0.001) whereas autoimmune disease was more frequent in BD compared to SCZ (p = 0.004) and HC (p = 0.003). sIL-2R was positively associated with autoimmune disease (p = 0.001) and negatively associated with PRS of SCZ (p = 0.006) across SCZ and HC; however, associations represented only small changes in the difference of sIL-2R levels between SCZ and HC.

CONCLUSION

There were few significant associations between rate of infections, autoimmune disease or PRS and altered immune markers in SCZ and BD, and the detected associations represented only small changes in the immune aberrations. The findings suggest that most of the low-grade inflammation in SCZ and BD is explained by other factors than the underlying PRS, autoimmunity and infection rates.

Influence of antipsychotics on metabolic syndrome risk in patients with schizophrenia

OBJECTIVE

Many studies so far have shown that antipsychotic therapy may have an effect on the development of metabolic syndrome in patients diagnosed with schizophrenia. Our goal was to determine whether our respondents are at risk for developing metabolic syndrome and who is more predisposed to it.

METHODS

In a stable phase, 60 patients diagnosed with schizophrenia were equally divided into three groups according to the drug (risperidone, clozapine, and aripiprazole monotherapy). Control group had 20 healthy examinees. Patients were evaluated first using The Positive and Negative Syndrome Scale (PANSS). Prolactin, lipid status, glycemia, insulin, cytokine values (IL-33, TGF-β, and TNF-α) and C-reactive protein (CRP) were measured. Also, Body mass index (BMI), Homeostatic Model Assesment for Insulin Resistance (HOMA index), waist and hip circumference (WHR) and blood pressure (TA) measurement were performed in the study.

RESULTS

Patients treated with risperidone compared to healthy control subjects and aripiprazol group of patients had statistically significant difference in prolactin levels. In clozapine group compared to healthy control group values of HDL cholesterol and glucose level were statistically significant different. In aripiprazole group compared to healthy control group value of BMI was statistically significant different. Statistically significant correlations were found in TNF-α with glucose and HOMA index in risperidone treated patients and with BMI in clozapine group of patients; IL-33 with glucose in risperidone and with BMI in clozapine group of patients and TGF-β with glucose in risperidone group, with insulin and HOMA index in clozapine group and statistically significant negative correlation with LDL cholesterol in aripiprazole group of patients.

CONCLUSION

Patients on risperidone and clozapine therapy may be at greater risk of developing metabolic syndrome than patients treated with aripiprazole. Statistically significant difference in concentration of TNF-α and TGF-β was in the group of patients treated with risperidone compared to healthy control group.

Elevated serum levels of TNF-α, IL-6, and IL-18 in chronic methamphetamine users

OBJECTIVE

Chronic methamphetamine use causes aberrant changes in cytokines. Our aim was to analyze the serum levels of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-18 in chronic methamphetamine users. Associations between cytokines levels with the demographic properties, methamphetamine use properties, and psychiatric symptoms in chronic methamphetamine users were also evaluated.

METHODS

Seventy-eight chronic methamphetamine users who did not continue methamphetamine exposure since hospitalization and 64 healthy controls were enrolled. Serum levels of TNF-α, IL-6, and IL-18 were detected using an enzyme-linked immunosorbent assay. Psychopathological symptoms of chronic methamphetamine users were evaluated by the Positive and Negative Syndrome Scale, Beck Depression Inventory (BDI), and Beck Anxiety Inventory.

RESULTS

Serum levels of TNF-α, IL-6, and IL-18 were significantly increased in methamphetamine users who did not continue methamphetamine exposure since hospital admission (average days since last methamphetamine use = 39.06 ± 7.48) when compared to those in controls. Serum IL-6 levels showed significant positive associations with BDI score and current frequency of methamphetamine use in chronic methamphetamine users.

CONCLUSIONS

Our results suggest that increased TNF-α, IL-6, and IL-18 levels may have an important role in chronic methamphetamine use-associated psychopathological symptoms.

The Effectiveness of Chlorpromazine to Decrease the Level of Tumor Necrosis Factor-Alpha Serum in Schizophrenic Patients with Coronavirus Disease 2019

BACKGROUND: The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus-2. The COVID-19 pandemic has also had an impact on mental health, including those with schizophrenia (SCH). There were 131 inpatient schizophrenic patients who were confirmed positive for COVID-19 at Dadi Makassar Hospital, South Sulawesi, Indonesia, but all of these patients did not experience any clinical symptoms of COVID-19. Chlorpromazine as an antipsychotic also has antiviral and anti-inflammatory effects in schizophrenic patients with COVID-19, and the schizophrenic neuroinflammatory is very likely to occur in patients with COVID-19 infection. AIM: The researchers tried to examine the effectiveness of chlorpromazine on serum TNF-values in schizophrenic patients with COVID-19. METHODS: This research is a nested case–control study. The study was conducted on schizophrenic patients with mild and asymptomatic cases of COVID-19 at Dadi Mental Hospital with a sample of 40 patients compared to 42 schizophrenic patients who were not COVID-19. Study subjects received chlorpromazine 100 mg/day for 4 weeks. Serum tumor necrosis factor-alpha (TNF-α) concentrations were measured by enzyme-linked immunosorbent assays when COVID-19 was first confirmed and after 4 weeks. Positive and negative syndrome scale (PANSS) and clinical global impression SCH (CGI-SCH) examinations were also performed to measure the clinical symptoms of SCH. RESULTS: The comparison of baseline TNF-serum levels that increased in the schizophrenic group with COVID-19 was 9.33 pg/ml higher, compared to the schizophrenic group without COVID-19. The decrease in TNF-levels in the schizophrenic group with COVID-19 of 7.96 pg/ml (p < 0.001) indicated an improvement in TNF-serum levels at week 4. Meanwhile, there was no significant decrease in serum TNF- levels in the non-COVID-19 schizophrenic group (p > 0.05). CONCLUSION: The serum TNF-value of schizophrenic patients with COVID-19 is higher than schizophrenic patients without COVID-19. Coadministration of chlorpromazine, antipsychotics, and COVID-19 therapy reduces serum TNF- values in schizophrenic patients with COVID-19. The administration of chlorpromazine and antipsychotic in therapeutic doses reduced the total PANSS and CGI-SCH values.

Relationship between TNF-α levels and psychiatric symptoms in first-episode drug-naïve patients with schizophrenia before and after risperidone treatment and in chronic patients

BACKGROUND

The influence of antipsychotic drugs on tumor necrosis factor-α (TNF-α) levels is unclear, and there is no consensus on the association between TNF-α and psychotic symptoms. This study aimed to investigate the differences in TNF-α levels and clinical correlations in first-episode drug-naïve (FEDN) patients with schizophrenia before and after treatment and in chronic patients.

METHODS

A total of 103 (51 FEDN and 52 chronic) patients and 114 healthy controls were recruited. Demographic and clinical data, including TNF-α levels, were recorded. We used the Positive and Negative Syndrome Scale (PANSS) to measure the psychopathology of all patients.

RESULTS

TNF-α levels before treatment were significantly higher in FEDN patients than in chronic patients and healthy controls. No significant sex differences were found in the TNF-α levels of patients with schizophrenia. The TNF-α levels before treatment were significantly positively related to changes in PANSS negative symptoms in FEDN patients. The TNF-α levels in chronic patients were significantly negatively correlated with the general psychopathology subscales and PANSS total scores.

CONCLUSIONS

Increased TNF-α levels in FEDN patients and their correlation with psychopathology indicate that inflammatory cytokines may play a crucial role in the etiopathogenesis of schizophrenia, and inflammation-directed therapy may, therefore, improve negative symptoms.

Zinc Supplementation During Pregnancy Alleviates Lipopolysaccharide-Induced Glial Activation and Inflammatory Markers Expression in a Rat Model of Maternal Immune Activation

Maternal immune activation (MIA) model has been profoundly described as a suitable approach to study the pathophysiological mechanisms of neuropsychiatric disorders, including schizophrenia. Our previous study revealed that prenatal exposure to lipopolysaccharide (LPS) induced working memory impairments in only male offspring. Based on the putative role of prefrontal cortex (PFC) in working memory process, the current study was conducted to examine the long-lasting effect of LPS-induced MIA on several neuroinflammatory mediators in the PFC of adult male pups. We also investigated whether maternal zinc supplementation can alleviate LPS-induced alterations in this region. Pregnant rats received intraperitoneal injections of either LPS (0.5 mg/kg) or saline on gestation days 15/16 and supplemented with ZnSO4 (30 mg/kg) throughout pregnancy. At postnatal day 60, the density of both microglia and astrocyte cells and the expression levels of IL-6, IL-1β, iNOS, TNF-α, NF-κB, and GFAP were evaluated in the PFC of male pups. Although maternal LPS treatment increased microglia and astrocyte density, number of neurons in the PFC of adult offspring remained unchanged. These findings were accompanied by the exacerbated mRNA levels of IL-6, IL-1β, iNOS, TNF-α, NF-κB, and GFAP as well. Conversely, prenatal zinc supplementation alleviated the mentioned alterations induced by LPS. These findings support the idea that the deleterious effects of prenatal LPS exposure could be attenuated by zinc supplementation during pregnancy. It is of interest to suggest early therapeutic intervention as a valuable approach to prevent neurodevelopmental deficits, following maternal infection. Schematic diagram describing the experimental timeline. On gestation days (GD) 15 and 16, pregnant dams were administered with intraperitoneal injections of either LPS (0.5 mg/kg) or vehicle and supplemented with ZnSO4 (30 mg/kg) throughout pregnancy by gavage. The resulting offspring were submitted to qPCR, immunostaining, and morphological analysis at PND 60. Maternal zinc supplementation alleviated increased expression levels of inflammatory mediators and microglia and astrocyte density induced by LPS in the PFC of treated offspring. PND postnatal day, PFC prefrontal cortex.

The Role of Cytokines in the Pathogenesis of Schizophrenia

Schizophrenia is a chronic mental illness of unknown etiology. A growing and compelling body of evidence implicates immunologic dysfunction as the key element in its pathomechanism. Cytokines, whose altered levels have been increasingly reported in various patient populations, are the major mediators involved in the coordination of the immune system. The available literature reports both elevated levels of proinflammatory as well as reduced levels of anti-inflammatory cytokines, and their effects on clinical status and neuroimaging changes. There is evidence of at least a partial genetic basis for the association between cytokine alterations and schizophrenia. Two other factors implicated in its development include early childhood trauma and disturbances in the gut microbiome. Moreover, its various subtypes, characterized by individual symptom severity and course, such as deficit schizophrenia, seem to differ in terms of changes in peripheral cytokine levels. While the use of a systematic review methodology could be difficult due to the breadth and diversity of the issues covered in this review, the applied narrative approach allows for a more holistic presentation. The aim of this narrative review was to present up-to-date evidence on cytokine dysregulation in schizophrenia, its effect on the psychopathological presentation, and links with antipsychotic medication. We also attempted to summarize its postulated underpinnings, including early childhood trauma and gut microbiome disturbances, and propose trait and state markers of schizophrenia.

Cytokine Level and Symptoms of Schizophrenia

BACKGROUND: The study was intended to find one of the cytokines, that is, tumor necrosis factor (TNF)-alpha correlation with PANSS scores of people with schizophrenia (PwS) and their differences compared to the healthy people of Malayan- Mongoloid Race. AIM: The aim of this study was providing a profile of TNF-alpha level in PwS of Malayan-Mongoloid race and its correlation with positive and negative symptoms in schizophrenia. METHODS: It was conducted using cross-sectional and following sampling methods, with inclusion and exclusion criteria set for the PwS and control groups. RESULTS: The result was no correlation between TNF-alpha levels with PANSS scores on PwS (p > 0.005), with very weak correlation and positive correlation direction, and there were differences in TNF-alpha levels.between PwS and control groups. CONCLUSION: It can be concluded that the higher levels of TNF-alpha would impact on the severity symptoms experienced by PwS.

Roles of inflammation in intrinsic pathophysiology and antipsychotic drug-induced metabolic disturbances of schizophrenia

Schizophrenia is a debilitating psychiatric illness that remains poorly understood. While the bulk of symptomatology has classically been associated with disrupted brain functioning, accumulating evidence demonstrates that schizophrenia is characterized by systemic inflammation and disturbances in metabolism. Indeed, metabolic disease is a major determinant of the high mortality rate associated with schizophrenia. Antipsychotic drugs (APDs) have revolutionized management of psychosis, making it possible to rapidly control psychotic symptoms. This has ultimately reduced relapse rates of psychotic episodes and improved overall quality of life for people with schizophrenia. However, long-term APD use has also been associated with significant metabolic disturbances including weight gain, dysglycemia, and worsening of the underlying cardiometabolic disease intrinsic to schizophrenia. While the mechanisms for these intrinsic and medication-induced metabolic effects remain unclear, inflammation appears to play a key role. Here, we review the evidence for roles of inflammatory mechanisms in the disease features of schizophrenia and how these mechanisms interact with APD treatment. We also discuss the effects of common inflammatory mediators on metabolic disease. Then, we review the evidence of intrinsic and APD-mediated effects on systemic inflammation in schizophrenia. Finally, we speculate about possible treatment strategies. Developing an improved understanding of inflammatory processes in schizophrenia may therefore introduce new, more effective options for treating not only schizophrenia but also primary metabolic disorders.

Chronic fatigue syndrome and fibromyalgia-like symptoms are an integral component of the phenome of schizophrenia: neuro-immune and opioid system correlates

Physiosomatic symptoms are an important part of schizophrenia phenomenology. The aim of this study is to examine the biomarker, neurocognitive and symptomatic correlates of physiosomatic symptoms in schizophrenia. We recruited 115 schizophrenia patients and 43 healthy controls and measured the Fibromyalgia and Chronic Fatigue Syndrome Rating (FF) scale, schizophrenia symptom dimensions, and the Brief Assessment of Cognition in Schizophrenia. We measured neuro-immune markers including plasma CCL11 (eotaxin), interleukin-(IL)-6, IL-10, Dickkopf protein 1 (DKK1), high mobility group box 1 protein (HMGB1) and endogenous opioid system (EOS) markers including κ-opioid receptor (KOR), μ-opioid receptor (MOR), endomorphin-2 (EM2) and β-endorphin. Patients with an increased FF score display increased ratings of psychosis, hostility, excitement, formal though disorders, psycho-motor retardation and negative symptoms as compared with patients with lower FF scores. A large part of the variance in the FF score (55.1%) is explained by the regression on digit sequencing task, token motor task, list learning, IL-10, age (all inversely) and IL-6 (positively). Neural network analysis shows that the top-6 predictors of the FF score are (in descending order): IL-6, HMGB1, education, MOR, KOR and IL-10. We found that 45.1% of the variance in a latent vector extracted from cognitive test scores, schizophrenia symptoms and the FF score was explained by HMGB1, MOR, EM2, DKK1, and CCL11. Physiosomatic symptoms are an integral part of the phenome of schizophrenia. Neurotoxic immune pathways and lowered immune regulation coupled with alterations in the EOS appear to drive the physiosomatic symptoms of schizophrenia.

Reduced Cell-Free Mitochondrial DNA Levels Were Induced by Antipsychotics Treatment in First-Episode Patients With Schizophrenia

Cell-free mitochondrial DNA (cf-mtDNA) is a damage-associated molecular pattern that boosts the release of cytokines and induces the immune response of the body; therefore, it is closely related to mental diseases. This study aims to evaluate a potential link between cf-mtDNA and clinical progression in first-episode patients with schizophrenia. In this study, plasma cf-mtDNA levels in 34 first-episode patients with schizophrenia before and after 8 weeks of antipsychotic treatment were examined. In addition, the clinical progression of first-episode schizophrenia was assessed using the Positive and Negative Syndrome Scale (PANSS). The copy number changes in the plasma cf-mtDNA (Δcf-mtDNA) were significantly correlated with changes in the PANSS scale scores (ΔPANSS) in first-episode patients with schizophrenia (ΔPANSS total score, P = 0.002; ΔPANSS positive score, P = 0.01). Plasma cf-mtDNA may represent a relevant tool in the future to assist in the assessment of clinical progression in first-episode patients with schizophrenia.

Associations Between the Kynurenine Pathway, Proinflammatory Cytokines, and Brain-Derived Neurotrophic Factor in Hospitalized Patients With Chronic Schizophrenia: A Preliminary Study

Purpose: The kynurenine (Kyn) pathway may play a role in the pathophysiology of schizophrenia. This pathway shows crosstalk with proinflammatory cytokines, including interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), and/or brain-derived neurotrophic factor (BDNF). Moreover, Kyn metabolites affect neurotransmission and cause neurotoxicity. To date, the influence of the Kyn pathway on proinflammatory cytokines and BDNF remains to be fully elucidated. The aim of this study was to investigate the relationships of the Kyn pathway with proinflammatory cytokines, BDNF, and psychiatric symptoms in patients with schizophrenia. Methods: Thirty patients with schizophrenia and ten healthy control participants were recruited for this study. All patients were diagnosed with schizophrenia using the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5). The healthy controls were those who did not fulfill any of the diagnostic criteria in the DSM-5. The serum levels of Kyn and its metabolites, proinflammatory cytokines, and BDNF were measured in patients with schizophrenia and healthy controls. Patients with schizophrenia were also assessed for psychiatric symptoms using the Positive and Negative Syndrome Scale (PANSS). Results: Patients with schizophrenia and healthy controls showed no significant differences in the levels of Kyn and its metabolites, proinflammatory cytokines, and BDNF. A significant positive correlation was found between the serum levels of TNF-α and Kyn (r = 0.53, p = 0.0026) and the Kyn/tryptophan (Trp) value (r = 0.67, p = 0.000046) in the schizophrenia group, but not in the healthy control group. Conclusion: TNF-α affects the Kyn pathway in patients with chronic schizophrenia, but not in the healthy individuals, although serum TNF-α levels showed no difference between the two groups. Associations between the Kyn pathway and the levels of proinflammatory cytokines and BDNF or psychotic symptoms might be complicated in hospitalized patients with chronic schizophrenia.

Alterations in Peripheral C-Reactive Protein and Inflammatory Cytokine Levels in Patients with Panic Disorder: A Systematic Review and Meta-Analysis

BACKGROUND

Accumulating evidence has shown the important role of the inflammatory process in the pathophysiology of mental disorders. However, the relative levels of inflammatory markers in patients with panic disorder (PD) have rarely been evaluated. The aim of the present study was to conduct a systematic review to determine the correlation of peripheral C-reactive protein (CRP) and inflammatory cytokine profiles with PD.

METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched for quantitative research studies published up to July 31, 2021 that measured peripheral levels of CRP and inflammatory cytokines in people with PD compared with controls. Meta-analysis using a random-effects model was performed for the levels of CRP and inflammatory cytokines with data from three or more studies.

RESULTS

Fourteen identified studies met the inclusion criteria. In total, 18 cytokines were evaluated. Markers that were reported in more than 3 studies were included in this meta-analysis. The results showed that peripheral levels of CRP, IL-6, IL-2 and TNF-α were significantly higher in PD patients than in healthy controls, while there was no significant difference in peripheral levels of IL-1β, IL-10 and IFN-γ between groups. Notably, the relevant studies involving IL-6, IL-1β, IL-10 and IFN-γ in PD patients were highly heterogeneous. Similar to meta-analyses of other inflammatory factors in mental disorders, our meta-analysis also reflected differences in participant medication use, comorbid anxiety or depression, sampling methods and detection methods. Eight inflammatory cytokines were reported in only one study, and their expression levels were higher, lower, or unchanged compared with those in healthy controls.

CONCLUSION

There is preliminary evidence to suggest a significant inflammatory response in PD patients, but the role of inflammatory markers in PD remains unclear. Studying inflammatory markers in PD will help to clarify the etiology and pathophysiological mechanisms of the disorder.

The Role of Peripheral Inflammation in Clinical Outcome and Brain Imaging Abnormalities in Psychosis: A Systematic Review

Promising research investigating the association between inflammatory biomarkers and response to antipsychotic and/or adjunctive therapy, observed by improvement in psychiatric assessment, is emerging. Increased inflammation has been suggested to contribute to higher severity of symptoms/treatment resistance through the effects that this has on brain structure and function. The present systematic review aims to clarify the potential role of peripheral inflammatory markers as predictors of clinical outcomes and their association with neuroimaging markers in patients with psychosis. Systematic searches of the literature using the databases PsychInfo, OVID Medline, and Embase were conducted to collate studies investigating the association of inflammatory biomarkers with clinical outcome in patients with psychotic disorders and studies examining the relationships between inflammatory biomarkers and neuroimaging data. Seventeen studies on predictors of clinical outcome and 14 on associations between neuroimaging data and inflammatory biomarkers in psychosis were identified, and risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). The main inflammatory markers associated with clinical outcome in psychosis were interleukin (IL)-6, IL-10, and C-reactive protein (CRP). High levels of CRP and IL-6 were associated with worse clinical outcome and deterioration of symptoms over time; in contrast, increased levels of IL-10 were associated with greater symptoms improvement. Smaller hippocampal volume and reduced cortical thickness were the main neuroimaging markers associated with increased peripheral inflammation. The heterogeneity across the studies (i.e., treatments strategies, duration) suggests that potential prediction power of inflammatory biomarkers could partially depend on the methodologies, supported by the overall NOS ratings of the studies. Future studies may need to consider whether a combination of these inflammatory and neuroimaging markers could further improve our ability of predicting clinical outcome in patients with psychosis.

Differences in cytokines between patients with generalised anxiety disorder and panic disorder

OBJECTIVE

The purpose of this study was to evaluate the differences among panic disorder (PD), generalised anxiety disorder (GAD) and controls in inflammatory cytokines. We also analysed the correlation between inflammatory cytokines and response to escitalopram in PD and GAD patients.

METHODS

Eighty-six patients with PD, 86 patients with GAD and 86 healthy controls were recruited for this study. All participants were, respectively, assessed for severity of anxiety and panic symptoms using the Hamilton Anxiety Rating Scale (HAMA) and the Panic Disorder Severity Scale (PDSS); all patients in the study were also assessed after 4 weeks of treatment. The serum levels of cytokines were measured using a flow fluorescence microsphere assay.

RESULTS

Both PD and GAD patients had higher serum levels of interleukin 6 (IL-6) than controls, and patients with PD showed significantly higher IL-6 than GAD patients. Significant positive correlations were found between the IFN-γ levels and the severity of anxiety in GAD patients. Higher level of IL-6 was associated with better response to escitalopram treatment in PD patients. However, the baseline levels of cytokines were not associated with treatment responses in GAD patients.

CONCLUSION

The present findings suggest that patients with PD may have higher levels of IL-6 than GAD, and higher baseline levels of IL-6 may be a better response to escitalopram in the treatment of PD.

Interaction between TNF-α and oxidative stress status in first-episode drug-naïve schizophrenia

There has been evidence that the disturbances of TNF-α and the oxidative stress (OxS) status are involved in the mechanism of schizophrenia. However, the results of their levels in schizophrenia are still controversial, and their interactions have not yet been examined, especially in first-episode drug-naïve (FEDN) patients. We therefore applied Enzyme-linked immunosorbent assays (ELISAs) method to compare peripheral blood serum TNF-α, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) levels in 119 FEDN patients with schizophrenia and 135 healthy controls. We found that TNF-α and MDA were higher, whereas GSH-Px was lower, in FEDN patients with schizophrenia compared to healthy controls (TNF-α, 2.21 ± 0.33 vs. 2.11 ± 0.36, Bonferroni p = 0.04; MDA, 2.95 ± 0.87 vs. 2.68 ± 0.76, Bonferroni p = 0.04, GSH-Px, 177.33 ± 28.84 vs. 188.32 ± 29.34, Bonferroni p = 0.03). Furthermore, TNF-α levels had an independent positive association with negative symptoms (r = 0.37, Bonferroni p < 0.001). Finally, GSH-Px levels were negatively associated with the presence of schizophrenia (B =-0.014, Wald statistic = 9.22, p = 0.002, 95 %CI = 0.97-0.99), while the interaction of TNF-α with MDA was a risk factor for schizophrenia (B = 0.22, Wald statistic = 10.06, p = 0.002, 95 %CI = 1.09-1.43). Our results suggest that TNF-α and disturbance of oxidative stress status as well as their interaction may be involved in the pathophysiology of schizophrenia.

Serum galectin-3 levels are decreased in schizophrenia

Objective:

To determine whether changes in serum galectin-3 (gal-3) concentrations in schizophrenia patients have etiopathogenetic importance. Since very little research has assessed the connection between galectins and schizophrenia, we wanted to examine alterations in the inflammatory marker gal-3 in schizophrenia and investigate possible correlations between clinical symptomatology and serum concentrations.

Methods:

Forty-eight schizophrenia patients and 44 healthy controls were included in this study. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS) were administered to determine symptom severity. Venous blood samples were collected, and serum gal-3 levels were measured.

Results:

Mean serum gal-3 levels were significantly lower in schizophrenia patients, and there were no significant differences in age or sex with the control group. There was also a significant positive correlation between serum gal-3 concentrations and negative schizophrenia symptoms according to the SANS.

Conclusion:

The results indicate that gal-3 is decreased in schizophrenia patients, which could contribute to inflammation in the pathogenesis of schizophrenia.

Lack of Association between the IL6R Gene Asp358Ala Variant (rs2228145), IL-6 Plasma Levels, and Treatment Resistance in Chilean Schizophrenic Patients Treated with Clozapine

Alterations in neuroinflammatory processes have been suggested to contribute to the development of Schizophrenia (SZ); one component of the inflammatory system that has been linked to this disorder is interleukin-6 (IL-6). The minor allele of rs2228145, a functional polymorphism in the IL-6 receptor gene, has been associated to elevated IL-6 plasma levels and increased inflammatory activity, making it an interesting candidate to study as a possible factor underlying clinical heterogeneity in SZ. We studied a sample of 100 patients undergoing treatment with clozapine. Their symptoms were quantified by Brief Psychotic Rating Scale; those with the lowest scores ("remitted") were compared with the highest ("clozapine treatment resistant"). We determined allelic frequencies for rs2228145 and IL-6 plasma levels. Our results do not support a role of IL-6 in response to treatment with clozapine. Further studies accounting for potential confounding factors are necessary.