The immune-mediated alteration of serotonin and glutamate: towards an integrated view of depression

The antipsychotic chlorpromazine reduces neuroinflammation by inhibiting microglial voltage-gated potassium channels

Neuroinflammation, the result of microglial activation, is associated with the pathogenesis of a wide range of psychiatric and neurological disorders. Recently, chlorpromazine (CPZ), a dopaminergic D2 receptor antagonist and schizophrenia therapy, was proposed to exert antiinflammatory effects in the central nervous system. Here, we report that the expression of Kv1.3 channel, which is abundant in T cells, is upregulated in microglia upon infection, and that CPZ specifically inhibits these channels to reduce neuroinflammation. In the mouse medial prefrontal cortex, we show that CPZ lessens Kv1.3 channel activity and reduces proinflammatory cytokine production. In mice treated with LPS, we found that CPZ was capable of alleviating both neuroinflammation and depression-like behavior. Our findings suggest that CPZ acts as a microglial Kv1.3 channel inhibitor and neuroinflammation modulator, thereby exerting therapeutic effects in neuroinflammatory psychiatric/neurological disorders.

Exosomes Derived from DPA-treated UCMSCs Attenuated Depression-like Behaviors and Neuroinflammation in a Model of Depression Induced by Chronic Stress

Depression is characterized by both neuroinflammation and neurodegeneration. Exosomes (Exo) have been shown to function as inhibitors of inflammation and promoters of neurogenesis. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid, can combat depression by increasing levels of docosapentaenoic acid (DPA). This study explored the effects of DPA on the therapeutic potential of Exo derived from human umbilical cord mesenchymal stem cells (hUCMSCs) in glia-induced neuroinflammation associated with depression. Exposure to chronic unpredictable mild stress (CUMS) over six weeks induced depression- and anxiety-like behaviors, while decreasing the levels of serotonin and dopamine. Molecularly, CUMS increased the concentrations of the microglial M1 markers Iba1, iNOS, and IL-1β, while reducing the M2 markers Arg1, CD206, and IL-10 in the prefrontal cortex and hippocampus. However, Exo therapy reversed these effects. Moreover, DPA treatment of Exo demonstrated superior efficacy in alleviating depressive behaviors, neurotransmitter deficiencies, and M1 microglial activation. In vitro, Exo suppressed LPS-stimulated BV2 cell viability and M1 microglial activation, while mitigating the SH-SY5Y cell apoptosis triggered by treatment with the conditioned medium from LPS-activated BV2 cells. Furthermore, administration of DPA enhanced this effect. Mechanically, DPA enhanced Exo function by upregulating miR125b-5p expression, thereby targeting the MyD88/TRAF6/NF-κB signaling pathway. In summary, Exo exhibited antidepressant effects by suppressing M1 microglial neuroinflammation, while DPA treatment provided a more potent therapeutic effect on depression-like changes through the upregulation of miR125b-5p targeting the MyD88/TRAF6/NF-κB pathway.

Convergence of endothelial dysfunction, inflammation and glucocorticoid resistance in depression-related cardiovascular diseases

Major Depressive Disorder, or depression, has been extensively linked to dysregulated HPA axis function, chronic inflammation and cardiovascular diseases. While the former two have been studied in depth, the mechanistic connection between depression and cardiovascular disease is unclear. As major mediators of vascular homeostasis, vascular pathology and immune activity, endothelial cells represent an important player connecting the diseases. Exaggerated inflammation and glucocorticoid function are important topics to explore in the endothelial response to MDD. Glucocorticoid resistance in several cell types strongly promotes inflammatory signaling and results in worsened severity in many diseases. However, endothelial health and inflammation in chronic stress and depression are rarely considered from the perspective of glucocorticoid signaling and resistance. In this review, we aim to discuss (1) endothelial dysfunction in depression, (2) inflammation in depression, (3) general glucocorticoid resistance in depression and (4) endothelial glucocorticoid resistance in depression co-morbid inflammatory diseases. We will first describe vascular pathology, inflammation and glucocorticoid resistance separately in depression and then describe their potential interactions with one another in depression-relevant diseases. Lastly, we will hypothesize potential mechanisms by which glucocorticoid resistance in endothelial cells may contribute to vascular disease states in depressed people. Overall, endothelial-glucocorticoid signaling may play an important role in connecting depression and vascular pathology and warrants further study.

Associations Between Neuropsychiatric Symptoms and Inflammation in Neurodegenerative Dementia: A Systematic Review

Background

Neuropsychiatric symptoms are common in dementia and linked to adverse outcomes. Inflammation is increasingly recognized as playing a role as a driver of early disease progression in Alzheimer's disease (AD) and related dementias. Inflammation has also been linked to primary psychiatric disorders, however its association with neuropsychiatric symptoms in neurodegenerative dementias remains uncertain.

Methods

We conducted a systematic literature review investigating associations between inflammation and neuropsychiatric symptoms in neurodegenerative dementias, including AD, Lewy body, Frontotemporal, Parkinson's (PD) and Huntington's disease dementias.

Results

Ninety-nine studies met our inclusion criteria, and the majority (n = 59) investigated AD and/or mild cognitive impairment (MCI). Thirty-five studies included PD, and only 6 investigated non-AD dementias. Inflammation was measured in blood, CSF, by genotype, brain tissue and PET imaging. Overall, studies exhibited considerable heterogeneity and evidence for specific inflammatory markers was inconsistent, with lack of replication and few longitudinal studies with repeat biomarkers. Depression was the most frequently investigated symptom. In AD, some studies reported increases in peripheral IL-6, TNF-a associated with depressive symptoms. Preliminary investigations using PET measures of microglial activation found an association with agitation. In PD, studies reported positive associations between TNF-a, IL-6, CRP, MCP-1, IL-10 and depression.

Conclusion

Central and peripheral inflammation may play a role in neuropsychiatric symptoms in neurodegenerative dementias; however, the evidence is inconsistent. There is a need for multi-site longitudinal studies with detailed assessments of neuropsychiatric symptoms combined with replicable peripheral and central markers of inflammation.

The role of kynurenines in migraine-related neuroimmune pathways

Migraine, a primary headache disorder whose mechanism remains incompletely understood, appears to involve the activation of the trigeminovascular system (TS) during attacks. Research suggests that inflammatory processes mediated by the immune system may play a role in migraine pathophysiology. Neuroinflammation is often associated with migraine attacks, with cytokines serving as crucial mediators in the process. Elevated levels of pro-inflammatory cytokines, such as interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), have been observed in the blood and cerebrospinal fluid of individuals experiencing migraine attacks. These cytokines have the capacity to sensitize pain pathways in the brain, thereby increasing sensitivity to pain stimuli. This phenomenon, known as central sensitization, is believed to contribute to the intensity and persistence of migraine pain. Kynurenines, endogenous mediators of glutamatergic mechanisms, can significantly influence the pathophysiology of primary headache disorders. The kynurenine system is collectively known as the kynurenine pathway (KP), which can act on multiple receptors, such as glutamate receptors, aryl hydrocarbon receptors (AhRs), G protein-coupled receptors 35 (GPR35), and α-7 nicotinic acetylcholine (α7 nACh) receptors. These receptors are also found on various cells of the immune system, so the role of the KP in the pathomechanism of primary headaches may also be mediated through them. In this review, our goal is to show a possible link between the receptors of the KP and immune system in the context of inflammation and migraine. Migraine research in recent years has focused on neuropeptides, such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) as potential pathogenic factors and possible therapeutic approaches. These peptides share many similarities in their characteristics and roles. For instance, they exhibit potent vasodilation, occur in both the peripheral and central nervous systems, and play a role in transmitting nociception and neurogenic inflammation. The investigation of potential connections between the aforementioned neuropeptides and the kynurenine pathway could play a significant role in uncovering the pathomechanism of migraine and identifying new drug candidates.

Regional Changes in Brain Biomolecular Markers in a Collagen-Induced Arthritis Rat Model

BACKGROUND

The effects of collagen-induced arthritis (CIA), a model of systemic inflammation, on brain regional molecular markers associated with neurological disorders are uncertain.

OBJECTIVE

This study investigated the brain regional molecular changes in markers associated with inflammation and neuronal dysfunction in a CIA model.

METHODS

Fourteen male Sprague Dawley rats were divided into control (n = 5) or CIA (n = 9) groups. 10 weeks after CIA induction, brain tissue was collected. Brain regional mRNA expression of inflammatory markers (IL-1β and IL-6), apoptotic markers (BAX and Bcl2) and neurotrophic factors (BDNF, CREB and TrkB) was determined. Monoamine distribution and abundance in different brain regions were determine by mass spectrometry imaging (MSI).

RESULTS

Neuroinflammation was confirmed in the CIA group by increased IL-β mRNA expression, concurrent with an increased BAX/Bcl2 ratio. The mRNA expression of CREB was increased in the midbrain and hippocampus while BDNF was increased and TrkB was decreased across all brain regions in CIA compared to control animals. Serotonin was decreased in the midbrain and hippocampus while dopamine was decreased in the striatum of CIA rats, compared to controls.

CONCLUSION

CIA resulted in neuroinflammation concurrent with an apoptotic state and aberrant expression of neurotrophic factors and monoamines in the brain, suggestive of neurodegeneration.

The complex role of the chemokine CX3CL1/Fractalkine in major depressive disorder: A narrative review of preclinical and clinical studies

Evidence suggests that neuroinflammation exhibits a dual role in the pathogenesis of major depressive disorder (MDD), both potentiating the onset of depressive symptoms and developing as a consequence of them. Our narrative review focuses on the role of the chemokine fractalkine (FKN) (also known as CX3CL1), which has gained increasing interest for its ability to induce changes to microglial phenotypes through interaction with its corresponding receptor (CX3CR1) that may impact neurophysiological processes relevant to MDD. Despite this, there is a lack of a clear understanding of the role of FKN in MDD. Overall, our review of the literature shows the involvement of FKN in MDD, both in preclinical models of depression, and in clinical studies of depressed patients. Preclinical studies (N = 8) seem to point towards two alternative hypotheses for FKN's role in MDD: a) FKN may drive pro-inflammatory changes to microglia that contribute towards MDD pathogenesis; or b) FKN may inhibit pro-inflammatory changes to microglia, thereby exerting a protective effect against MDD pathogenesis. Evidence for a) primarily derives from preclinical chronic stress models of depression in mice, whereas for b) from preclinical inflammation models of depression. Whereas, in humans, clinical studies (N = 4) consistently showed a positive association between FKN and presence of MDD, however it is not clear whether FKN is driving or moderating MDD pathogenesis. Future studies should aim for larger and more controlled clinical cohorts, in order to advance our understanding of FKN role both in the context of stress and/or inflammation.

Antidepressant Effect of Heracleum moellendorffii Extract on Behavioral Changes in Astrocyte Ablation Mouse Model of Depression by Modulating Neuroinflammation through the Inhibition of Lipocalin-2

Astrocyte dysfunction and inflammation play a pivotal role in depression. In this study, we evaluated the antidepressant properties of Heracleum moellendorffii root extract (HME), which is traditionally used for inflammation-related diseases, in a mouse model with astrocyte depletion that resembles the prefrontal cortex pathology of depressive patients. Mice were divided into four groups, with 10 mice per group. To induce astrocyte ablation in the mice's prefrontal cortex (PFC), we used astrocytic toxin L-alpha-aminoadipic acid (L-AAA) and administered HME orally at 200 and 500 mg/kg for 22 days. We utilized the tail suspension test (TST) to assess depression-like behaviors and the open field test (OFT) to evaluate anxiety-like activities. Additionally, astrocytic and inflammatory markers in the PFC were evaluated using immunohistochemistry and ELISA. The results showed that infusion of L-AAA significantly decreased the expression of astrocytic glial fibrillary acidic protein (GFAP), which was accompanied by increased depression and anxiety-like behaviors. However, HME significantly reversed these effects by dose-dependently enhancing GFAP expression and modulating inflammatory markers, such as TNF-α, IL-6, and particularly lipocalin-2, a master proinflammatory mediator. These results imply that HME contributes to the alleviation of depression and anxiety-like behaviors by promoting astrocyte recovery and reducing neuroinflammation, especially through lipocalin-2 inhibition.

Unveiling the hidden pathways: Exploring astrocytes as a key target for depression therapy

Depressive disorders are widely debilitating psychiatric disease. Despite the considerable progress in the field of depression therapy, extensive research spanning many decades has failed to uncover pathogenic pathways that might aid in the creation of long-acting and rapid-acting antidepressants. Consequently, it is imperative to reconsider existing approaches and explore other targets to improve this area of study. In contemporary times, several scholarly investigations have unveiled that persons who have received a diagnosis of depression, as well as animal models employed to study depression, demonstrate a decrease in both the quantity as well as density of astrocytes, accompanied by alterations in gene expression and morphological attributes. Astrocytes rely on a diverse array of channels and receptors to facilitate their neurotransmitter transmission inside tripartite synapses. This study aimed to investigate the potential processes behind the development of depression, specifically focusing on astrocyte-associated neuroinflammation and the involvement of several molecular components such as connexin 43, potassium channel Kir4.1, aquaporin 4, glutamatergic aspartic acid transporter protein, SLC1A2 or GLT-1, glucocorticoid receptors, 5-hydroxytryptamine receptor 2B, and autophagy, that localized on the surface of astrocytes. The study also explores novel approaches in the treatment of depression, with a focus on astrocytes, offering innovative perspectives on potential antidepressant medications.

Neuroimmune modulation by tryptophan derivatives in neurological and inflammatory disorders

The nervous and immune systems are highly developed, and each performs specialized physiological functions. However, they work together, and their dysfunction is associated with various diseases. Specialized molecules, such as neurotransmitters, cytokines, and more general metabolites, are essential for the appropriate regulation of both systems. Tryptophan, an essential amino acid, is converted into functional molecules such as serotonin and kynurenine, both of which play important roles in the nervous and immune systems. The role of kynurenine metabolites in neurodegenerative and psychiatric diseases has recently received particular attention. Recently, we found that hyperactivity of the kynurenine pathway is a critical risk factor for septic shock. In this review, we first outline neuroimmune interactions and tryptophan derivatives and then summarized the changes in tryptophan metabolism in neurological disorders. Finally, we discuss the potential of tryptophan derivatives as therapeutic targets for neuroimmune disorders.

Correlation of Sociodemographic Factors, Characteristics of Burns, and Neutrophil-to-Lymphocyte Ratio with the Level of Depression in Patients with Burn injuries

Background

The most common psychological impact experienced by patients with burn injuries is depression. Several significant risk factors influence depression, including sociodemographic factors (gender, employment status, socioeconomic status, and marital status) and burn characteristics (burn depth, burn area, and total burn surface area). Neutrophil-to-lymphocyte ratio (NLR) was discovered as a new biomarker for depression detection. The purpose of this study was to investigate the correlation of sociodemographic factors, burn characteristics, and NLR with the severity of depression in patients with burn injuries.

Methods

This analytic descriptive study was conducted at Dr. Hasan Sadikin General Hospital from June 2022 to April 2023. Samples were assessed by a psychiatrist using the Hamilton Depression Rating Scale instrument, and a differential white blood count was calculated to obtain the NLR value.

Results

The study sample consisted of 32 patients, including 27 males and 6 females. There was no correlation of sociodemographic factors and burn wound characteristics with the level of depression. NLR in patients with burn injuries who had no depression, mild depression, and moderate depression was 5.78 ± 2.23, 7.4 ± 1.77, and 13.04 ± 6.25, respectively. NLR was statistically significantly associated with the level of depression in patients with burn injuries (p = 0.001).

Conclusion

There was no correlation of sociodemographic factors and burn characteristics with the level of depression. There was a significant correlation between NLR and the level of depression in patients with burn injuries at Dr. Hasan Sadikin General Hospital.

Exploring the Psychiatric Manifestations of Primary Sjögren's Syndrome: A Narrative Review

Background

Primary Sjögren's syndrome (pSS) is recognized for its autoimmune origin. Its hallmark symptoms, dry eyes and mouth, result from glandular inflammation. Prior literature indicates that pSS not only affects the peripheral system but also involves the central nervous system (CNS), giving rise to various neuropsychiatric symptoms. However, there is limited published research on the psychiatric comorbidities in individuals with pSS.

Methods

A comprehensive search was conducted on PubMed and Google Scholar for this narrative review. The search spanned from inception until August 2023. Its aim was to locate studies focusing on the psychiatric manifestations of pSS and the potential underlying mechanisms.

Results

The most commonly reported psychiatric complications among these individuals are depression and cognitive dysfunction. Other psychiatric manifestations that have been reported in pSS individuals include anxiety, sleep disorders, psychosis, catatonia, bipolar disorder, and obsessive-compulsive disorder.

Conclusion

In conclusion, patients with pSS often display multiple psychiatric symptoms. These symptoms can significantly impair functioning and reduce quality of life. Hence, prompt diagnosis and management are crucial.

Unraveling the Role of the Blood-Brain Barrier in the Pathophysiology of Depression: Recent Advances and Future Perspectives

Depression is a highly prevalent psychological disorder characterized by persistent dysphoria, psychomotor retardation, insomnia, anhedonia, suicidal ideation, and a remarkable decrease in overall well-being. Despite the prevalence of accessible antidepressant therapies, many individuals do not achieve substantial improvement. Understanding the multifactorial pathophysiology and the heterogeneous nature of the disorder could lead the way toward better outcomes. Recent findings have elucidated the substantial impact of compromised blood-brain barrier (BBB) integrity on the manifestation of depression. BBB functions as an indispensable defense mechanism, tightly overseeing the transport of molecules from the periphery to preserve the integrity of the brain parenchyma. The dysfunction of the BBB has been implicated in a multitude of neurological disorders, and its disruption and consequent brain alterations could potentially serve as important factors in the pathogenesis and progression of depression. In this review, we extensively examine the pathophysiological relevance of the BBB and delve into the specific modifications of its components that underlie the complexities of depression. A particular focus has been placed on examining the effects of peripheral inflammation on the BBB in depression and elucidating the intricate interactions between the gut, BBB, and brain. Furthermore, this review encompasses significant updates on the assessment of BBB integrity and permeability, providing a comprehensive overview of the topic. Finally, we outline the therapeutic relevance and strategies based on BBB in depression, including COVID-19-associated BBB disruption and neuropsychiatric implications. Understanding the comprehensive pathogenic cascade of depression is crucial for shaping the trajectory of future research endeavors.

Immunotherapy for depression: Recent insights and future targets

Depression stands as a prominent contributor to global disability, entailing an elevated risk of suicide. Substantial evidence supports the notion that immune dysregulation may play a role in the development of depression and impede responses to antidepressant treatments. Immune dysregulation may cause depression in susceptible individuals through raising inflammatory responses. Differences in immune cell types and the release of pro-inflammatory mediators are observed in the blood and cerebrospinal fluid of patients with major depressive disorder, which is associated with neuroimmune dysfunction. Therefore, the interaction of peripheral and central immune targets in depression needs to be understood. Urgent attention is required for the development of innovative therapeutics directed at modulating immune responses for the treatment of depression. This review delineates the immune mechanisms involved in the pathogenesis of depression, assesses the therapeutic potential of immune system targeting for depression treatment, and deliberates on the merits and constraints of employing immunotherapy in the management of depression.

Depression in Rheumatoid Arthritis: Prevalence and Effects on Disease Activity

Background:The primary objective of this study was to estimate depression's prevalence in a cohort of rheumatoid arthritis (RA) patients, and the secondary objective was to evaluate the impact of depression on disease activity over time. Methods: We included all patients with RA presenting to our clinic from 2019 to 2020, who had three follow-up visits available. Depression prevalence was calculated using the patient's history of diagnosed depression, and disease activity was assessed using the disease activity score for 28 joints (DAS28) and its components: tender joint count (TJC), swollen joint count (SJC), pain value on a visual analog scale (VAS), and inflammatory markers. Results: A total of 400 RA patients were included, 75 of whom had diagnosed depression, generating a prevalence of 18.8%. The mean values of DAS28 and its components were higher, with statistical significance, in the depression subgroup at all three follow-ups (p < 0.001). Conclusions: Depression is prevalent in the RA population, and leads to higher disease activity in dynamic evaluations. Assessing depression could be a psychological marker for RA prognosis with an important outcome in controlling disease activity.

Anti-angiogenic mechanisms and serotonergic dysfunction in the Rgs2 knockout model for the study of psycho-obstetric risk

Psychiatric and obstetric diseases are growing threats to public health and share high rates of co-morbidity. G protein-coupled receptor signaling (e.g., vasopressin, serotonin) may be a convergent psycho-obstetric risk mechanism. Regulator of G Protein Signaling 2 (RGS2) mutations increase risk for both the gestational disease preeclampsia and for depression. We previously found preeclampsia-like, anti-angiogenic obstetric phenotypes with reduced placental Rgs2 expression in mice. Here, we extend this to test whether conserved cerebrovascular and serotonergic mechanisms are also associated with risk for neurobiological phenotypes in the Rgs2 KO mouse. Rgs2 KO exhibited anxiety-, depression-, and hedonic-like behaviors. Cortical vascular density and vessel length decreased in Rgs2 KO; cortical and white matter thickness and cell densities were unchanged. In Rgs2 KO, serotonergic gene expression was sex-specifically changed (e.g., cortical Htr2a, Maoa increased in females but all serotonin targets unchanged or decreased in males); redox-related expression increased in paraventricular nucleus and aorta; and angiogenic gene expression was changed in male but not female cortex. Whole-cell recordings from dorsal raphe serotonin neurons revealed altered 5-HT1A receptor-dependent inhibitory postsynaptic currents (5-HT1A-IPSCs) in female but not male KO neurons. Additionally, serotonin transporter blockade by the SSRI sertraline increased the amplitude and time-to-peak of 5-HT1A-IPSCs in KO neurons to a greater extent than in WT neurons in females only. These results demonstrate behavioral, cerebrovascular, and sertraline hypersensitivity phenotypes in Rgs2 KOs, some of which are sex-specific. Disruptions may be driven by vascular and cell stress mechanisms linking the shared pathogenesis of psychiatric and obstetric disease to reveal future targets.

Lower serum insulin-like growth factor 2 level in patients with bipolar disorder is associated with the severity of manic symptoms during manic episodes

Objective

Accumulating evidence has indicated that neurodevelopmental defects may underlie the pathophysiology of bipolar disorder (BD). Insulin-like growth factors (IGFs) are a family of neurotrophic factors that are essential for the survival and development of neurons. The present study aims to investigate whether IGF-2 signaling is implicated in the pathophysiological processes of BD.

Method

50 healthy controls and 78 patients with BD, including 23 patients who diagnosed acute depressive episode and 55 patients who diagnosed acute manic episode, were recruited in this study. The 17-item Hamilton Depression Rating Scale (HAMD-17) and the Young Mania Rating Scale (YMRS) were used to assess the severity of the depressive and manic symptoms, respectively. The serum IGF-2 level was determined by an enzyme-linked immunosorbent assay (ELISA). The Kolmogorov-Smirnov and Mann-Whitney U tests were used for between-group comparisons and spearman analysis was used to analyze correlations.

Results

Patients with BD had lower serum IGF-2 levels (66.08 ± 21.22 ng/ml) when compared to healthy controls (88.72 ± 31.55 ng/ml). BD patients were divided into manic episode and depressive episode subgroups. We found that serum IGF-2 levels were reduced in both the mania and depression subgroups (mania: 67.19 ± 21.52 ng/ml, depression: 63.43 ± 20.67 ng/ml; P < 0.001), while no significant difference was observed between two groups (P > 0.05). Spearman correlation analyses revealed that the levels of serum IGF-2 were negatively correlated with the YMRS scores in BD patients (r = -0.522, P < 0.001). Furthermore, IGF-2 was found to be an independent contributor to the severity of symptoms in patients with manic episodes (B = -0.610, t = -5.299, P < 0.001).

Conclusion

Lower serum IGF-2 levels were found in BD patients and correlated with the severity of the manic symptoms in these patients during manic episodes. These results suggest that reduced IGF-2 levels might be involved in the pathophysiology of BD, and serum IGF-2 could be a peripheral biomarker for the evaluation of the severity of manic symptoms in BD patients.

Neutrophil-to-lymphocyte ratio as a predictive biomarker for early diagnosis of depression: A narrative review

Depression is a mood disorder that causes persistent feelings of sadness, hopelessness, loss of interest, and decreased energy. Early diagnosis of depression can improve its negative impacts and be effective in its treatment. Previous studies have indicated that inflammation plays an important role in the initiation and development of depression, hence, various inflammatory biomarkers have been investigated for early diagnosis of depression, the most popular of which are blood biomarkers. The Neutrophil to lymphocyte ratio (NLR) may be more informative in the early diagnosis of depression than other widely used markers, such as other leukocyte characteristics or interleukins. Considering the importance of early diagnosis of depression and the role of NLR in early diagnosis of depression, our paper reviews the literature on NLR as a diagnostic biomarker of depression, which may be effective in its treatment. Various studies have shown that elevated NLR is associated with depression, suggesting that NLR may be a valuable, reproducible, easily accessible, and cost-effective method for the evaluation of depression and it may be used in outpatient clinic settings. Closer follow-up can be performed for these patients who have higher NLR levels. However, it seems that further studies on larger samples, taking into account important confounding factors, and assessing them together with other inflammatory markers are necessary to draw some conclusive statements.

Investigating causal associations among gut microbiota, metabolites, and psoriatic arthritis: a Mendelian randomization study

Background

Currently, there has been observed a significant alteration in the composition of the gut microbiome (GM) and serum metabolites in patients with psoriatic arthritis (PsA) compared to healthy individuals. However, previous observational studies have shown inconsistent results regarding the alteration of gut microbiota/metabolites. In order to shed light on this matter, we utilized Mendelian randomization to determine the causal effect of GM/metabolites on PsA.

Methods

We retrieved summary-level data of GM taxa/metabolites and PsA from publicly available GWAS statistics. Causal relationships between GM/metabolites and PsA were determined using a two-sample MR analysis, with the IVW approach serving as the primary analysis method. To ensure the robustness of our findings, we conducted sensitivity analyses, multivariable MR analysis (MVMR), and additional analysis including replication verification analysis, LDSC regression, and Steiger test analysis. Furthermore, we investigated reverse causality through a reverse MR analysis. Finally, we conducted an analysis of expression quantitative trait loci (eQTLs) involved in the metabolic pathway to explore potential molecular mechanisms of metabolism.

Results

Our findings reveal that eight GM taxa and twenty-three serum metabolites are causally related to PsA (P < 0.05). Notably, a higher relative abundance of Family Rikenellaceae (ORIVW: 0.622, 95% CI: 0.438-0.883, FDR = 0.045) and elevated serum levels of X-11538 (ORIVW: 0.442, 95% CI: 0.250-0.781, FDR = 0.046) maintain significant causal associations with a reduced risk of PsA, even after adjusting for multiple testing correction and conducting MVMR analysis. These findings suggest that Family Rikenellaceae and X-11538 may have protective effects against PsA. Our sensitivity analysis and additional analysis revealed no significant horizontal pleiotropy, reverse causality, or heterogeneity. The functional enrichment analysis revealed that the eQTLs examined were primarily associated with glycerolipid metabolism and the expression of key metabolic factors influenced by bacterial infections (Vibrio cholerae and Helicobacter pylori) as well as the mTOR signaling pathway.

Conclusion

In conclusion, our study demonstrates that Family Rikenellaceae and X-11538 exhibit a strong and negative causal relationship with PsA. These particular GM taxa and metabolites have the potential to serve as innovative biomarkers, offering valuable insights into the treatment and prevention of PsA. Moreover, bacterial infections and mTOR-mediated activation of metabolic factors may play an important role in this process.

A cross talk on the role of contemporary biomarkers in depression

Introduction: Biomarkers can be used to identify determinants of response to various treatments of mental disorders. Evidence to date demonstrates that markers of inflammatory, neurotransmitter, neurotrophic, neuroendocrine, and metabolic function can predict the psychological and physical consequences of depression in individuals, allowing for the development of new therapeutic targets with fewer side effects. Extensive research has included hundreds of potential biomarkers of depression, but their roles in depression, abnormal patients, and how bioinformatics can be used to improve diagnosis, treatment, and prognosis have not been determined or defined. To determine which biomarkers can and cannot be used to predict treatment response, classify patients for specific treatments, and develop targets for new interventions, proprietary strategies, and current research projects need to be tailored.Material and Methods: This review article focuses on - biomarker systems that would help in the further development and expansion of newer targets - which holds great promise for reducing the burden of depression.Results and Discussion: Further, this review point to the inflammatory response, metabolic marker, and microribonucleic acids, long non-coding RNAs, HPA axis which are - related to depression and can serve as future targets.

Quantile regression to explore association of sleep duration with depression among adults in NHANES and KNHANES

BACKGROUND

Sleep duration has been associated with depression. However, mean regression, such as linear regression or logistic regression, may not capture relationships that occur mainly in the tails of outcome distribution. This study aimed to evaluate the associations between sleep duration and depression along the entire distribution of depression using quantile regression approach.

METHODS

This study included 55,954 adults aged 18 to 80 years from the National Health and Nutrition Examination Survey (N = 34,156) and the Korea National Health and Nutrition Examination Survey (N = 21,798). The coefficients corresponding to cross-group differences in PHQ-9 scores were estimated when comparing short or long sleep duration with normal sleep duration on deciles of PHQ-9 score distribution.

RESULTS

At lower quantiles, either short or long sleep duration was not associated with depression. At higher quantiles, the association of both short and long sleep duration with depression became much more pronounced. Compared with normal sleep duration, short and long sleep duration were associated with increases of 1.34 (95 % CI: 1.16, 1.51) and 0.28 (95 % CI: 0.04, 0.52) in PHQ-9 scores at the 50th quantile, while the corresponding increases were 3.27 (95 % CI: 2.83, 3.72) and 1.65 (95 % CI: 0.86, 2.45) at the 90th quantile, respectively. We also found that the magnitude of association between short sleep duration and depression was stronger among females and individuals with chronic diseases.

CONCLUSIONS

The beneficial effect of sufficient sleep in decreasing depression severity may be more evident among individuals with severe depression. Further studies could explore whether these heterogeneous associations can be generalized to populations with different characteristics.

Single-cell RNA sequencing reveals that the immunosuppression landscape induced by chronic stress promotes colorectal cancer metastasis

The high prevalence of depressive disorders in individuals with cancer and their contribution to tumour progression is a topic that is gradually gaining attention. Recent evidence has shown that there are prominent connections between immune gene variants and mood disorders. The homeostasis of the tumour immune microenvironment (TIME) and the infiltration and activation of immune cells play a very important role in the antitumour effect. In this study, we established a compound mouse model with chronic unpredictable mild stress (CUMS) and orthotopic colorectal cancer to simulate colorectal cancer (CRC) patients with depression. Using 10✕Genomics single-cell transcriptome sequencing technology, we profiled nearly 30,000 cells from tumour samples of 8 mice from the control and CUMS groups, revealed that immune cells in tumours under a chronic stress state trend toward a more immunosuppressive and exhaustive status, and described the crosstalk between the overall inflammatory environment and immunosuppressive landscape to provide mechanistic information or efficacious strategies for immune-oncology treatments in CRC with depressive disorders.

Microbes and Mental Illness: Past, Present, and Future

A review of the association between microbes and mental illness is performed, including the history, relevant definitions, infectious agents associated with mental illnesses, complex interactive infections, total load theory, pathophysiology, psychoimmunology, psychoneuroimmunology, clinical presentations, early-life infections, clinical assessment, and treatment. Perspectives on the etiology of mental illness have evolved from demonic possession toward multisystem biologically based models that include gene expression, environmental triggers, immune mediators, and infectious diseases. Microbes are associated with a number of mental disorders, including autism, schizophrenia, bipolar disorder, depressive disorders, and anxiety disorders, as well as suicidality and aggressive or violent behaviors. Specific microbes that have been associated or potentially associated with at least one of these conditions include Aspergillus, Babesia, Bartonella, Borna disease virus, Borrelia burgdorferi (Lyme disease), Candida, Chlamydia, coronaviruses (e.g., SARS-CoV-2), Cryptococcus neoformans, cytomegalovirus, enteroviruses, Epstein-Barr virus, hepatitis C, herpes simplex virus, human endogenous retroviruses, human immunodeficiency virus, human herpesvirus-6 (HHV-6), human T-cell lymphotropic virus type 1, influenza viruses, measles virus, Mycoplasma, Plasmodium, rubella virus, Group A Streptococcus (PANDAS), Taenia solium, Toxoplasma gondii, Treponema pallidum (syphilis), Trypanosoma, and West Nile virus. Recognition of the microbe and mental illness association with the development of greater interdisciplinary research, education, and treatment options may prevent and reduce mental illness morbidity, disability, and mortality.

Brain signatures of chronic gut inflammation

Gut inflammation is thought to modify brain activity and behaviour via modulation of the gut-brain axis. However, how relapsing and remitting exposure to peripheral inflammation over the natural history of inflammatory bowel disease (IBD) contributes to altered brain dynamics is poorly understood. Here, we used electroencephalography (EEG) to characterise changes in spontaneous spatiotemporal brain states in Crohn's Disease (CD) (n = 40) and Ulcerative Colitis (UC) (n = 30), compared to healthy individuals (n = 28). We first provide evidence of a significantly perturbed and heterogeneous microbial profile in CD, consistent with previous work showing enduring and long-standing dysbiosis in clinical remission. Results from our brain state assessment show that CD and UC exhibit alterations in the temporal properties of states implicating default-mode network, parietal, and visual regions, reflecting a shift in the predominance from externally to internally-oriented attentional modes. We investigated these dynamics at a finer sub-network resolution, showing a CD-specific and highly selective enhancement of connectivity between the insula and medial prefrontal cortex (mPFC), regions implicated in cognitive-interoceptive appraisal mechanisms. Alongside overall higher anxiety scores in CD, we also provide preliminary support to suggest that the strength of chronic interoceptive hyper-signalling in the brain co-occurs with disease duration. Together, our results demonstrate that a long-standing diagnosis of CD is, in itself, a key factor in determining the risk of developing altered brain network signatures.

Mitochondrial dysfunction: A fatal blow in depression

Mitochondria maintain the normal physiological function of nerve cells by producing sufficient cellular energy and performing crucial roles in maintaining the metabolic balance through intracellular Ca2+ homeostasis, oxidative stress, and axonal development. Depression is a prevalent psychiatric disorder with an unclear pathophysiology. Damage to the hippocampal neurons is a key component of the plasticity regulation of synapses and plays a critical role in the mechanism of depression. There is evidence suggesting that mitochondrial dysfunction is associated with synaptic impairment. The maintenance of mitochondrial homeostasis includes quantitative maintenance and quality control of mitochondria. Mitochondrial biogenesis produces new and healthy mitochondria, and mitochondrial dynamics cooperates with mitophagy to remove damaged mitochondria. These processes maintain mitochondrial population stability and exert neuroprotective effects against early depression. In contrast, mitochondrial dysfunction is observed in various brain regions of patients with major depressive disorders. The accumulation of defective mitochondria accelerates cellular nerve dysfunction. In addition, impaired mitochondria aggravate alterations in the brain microenvironment, promoting neuroinflammation and energy depletion, thereby exacerbating the development of depression. This review summarizes the influence of mitochondrial dysfunction and the underlying molecular pathways on the pathogenesis of depression. Additionally, we discuss the maintenance of mitochondrial homeostasis as a potential therapeutic strategy for depression.

Neuroprotective astroglial response to neural damage and its relevance to affective disorders

Astrocytes not only support neuronal function with essential roles in synaptic neurotransmission, action potential propagation, metabolic support, or neuroplastic and developmental adaptations. They also respond to damage or dysfunction in surrounding neurons and oligodendrocytes by releasing neurotrophic factors and other molecules that increase the survival of the supported cells or contribute to mechanisms of structural and molecular restoration. The neuroprotective responsiveness of astrocytes is based on their ability to sense signals of degeneration, metabolic jeopardy and structural damage, and on their aptitude to locally deliver specific molecules to remedy threats to the molecular and structural features of their cellular partners. To the extent that neuronal and other glial cell disturbances are known to occur in affective disorders, astrocyte responsiveness to those disturbances may help to better understand the roles astrocytes play in affective disorders. The astrocytic sensing apparatus supporting those responses involves receptors for neurotransmitters, purines, cell adhesion molecules and growth factors. Astrocytes also share with the immune system the capacity of responding to cytokines released upon neuronal damage. In addition, in responses to specific signals astrocytes release unique factors such as clusterin or humanin that have been shown to exert potent neuroprotective effects. Astrocytes integrate the signals above to further deliver structural lipids, removing toxic metabolites, stabilizing the osmotic environment, normalizing neurotransmitters, providing anti-oxidant protection, facilitating synaptogenesis and acting as barriers to contain varied deleterious signals, some of which have been described in brain regions relevant to affective disorders and related animal models. Since various of the injurious signals that activate astrocytes have been implicated in different aspects of the etiopathology of affective disorders, particularly in relation to the diagnosis of depression, potentiating the corresponding astrocyte neuroprotective responses may provide additional opportunities to improve or complement available pharmacological and behavioral therapies for affective disorders.

Brain-specific Pd1 deficiency leads to cortical neurogenesis defects and depressive-like behaviors in mice

Embryonic neurogenesis is tightly regulated by multiple factors to ensure the precise development of the cortex. Deficiency in neurogenesis may result in behavioral abnormalities. Pd1 is a well-known inhibitory immune molecule, but its function in brain development remains unknown. Here, we find brain specific deletion of Pd1 results in abnormal cortical neurogenesis, including enhanced proliferation of neural progenitors and reduced neuronal differentiation. In addition, neurons in Pd1 knockout mice exhibit abnormal morphology, both the total length and the number of primary dendrites were reduced. Moreover, Pd1cKO mice exhibit depressive-like behaviors, including immobility, despair, and anhedonia. Mechanistically, Pd1 regulates embryonic neurogenesis by targeting Pax3 through the β-catenin signaling pathway. The constitutive expression of Pax3 partly rescues the deficiency of neurogenesis in the Pd1 deleted embryonic brain. Besides, the administration of β-catenin inhibitor, XAV939, not only rescues abnormal brain development but also ameliorates depressive-like behaviors in Pd1cKO mice. Simultaneously, Pd1 plays a similar role in human neural progenitor cells (hNPCs) proliferation and differentiation. Taken together, our findings reveal the critical role and regulatory mechanism of Pd1 in embryonic neurogenesis and behavioral modulation, which could contribute to understanding immune molecules in brain development.

Gut and oral microbiome modulate molecular and clinical markers of schizophrenia-related symptoms: A transdiagnostic, multilevel pilot study

Although increasing evidence links microbial dysbiosis with the risk for psychiatric symptoms through the microbiome-gut-brain axis (MGBA), the specific mechanisms remain poorly characterized. In a diagnostically heterogeneous group of treated psychiatric cases and nonpsychiatric controls, we characterized the gut and oral microbiome, plasma cytokines, and hippocampal inflammatory processes via proton magnetic resonance spectroscopic imaging (1H-MRSI). Using a transdiagnostic approach, these data were examined in association with schizophrenia-related symptoms measured by the Positive and Negative Syndrome Scale (PANSS). Psychiatric cases had significantly greater heterogeneity of gut alpha diversity and an enrichment of pathogenic taxa, like Veillonella and Prevotella, in the oral microbiome, which was an accurate classifier of phenotype. Cases exhibited significantly greater positive, negative, and general PANSS scores that uniquely correlated with bacterial taxa. Strong, positive correlations of bacterial taxa were also found with cytokines and hippocampal gliosis, dysmyelination, and excitatory neurotransmission. This pilot study supports the hypothesis that the MGBA influences psychiatric symptomatology in a transdiagnostic manner. The relative importance of the oral microbiome in peripheral and hippocampal inflammatory pathways was highlighted, suggesting opportunities for probiotics and oral health to diagnose and treat psychiatric conditions.

Management protocols of chronic Orofacial Pain: A Systematic Review

Objective

Chronic orofacial pain (CP) is a persistent and debilitating condition that affects the face, mouth, and jaw and can have a significant impact on an individual's quality of life by posing problems to eat, speak, and perform everyday activities. By the means of this narrative review, we aim to assess different types of management modalities that exist to combat chronic orofacial pain.

Design

Various databases were explored with MeSH keywords of chronic orofacial pain, orofacial pain, and interventions and treatment protocols for eligible articles. After an extensive literature search, it was ascertained that this review identified four major categories of treatment modalities for the management of chronic orofacial pain, namely pharmacological management, psychological management, lifestyle interventions-based management, and current stimulation-based management.

Results

Of the four categories discussed, although pharmacological intervention offered the most immediate relief-especially from orofacial pain that was of a sudden, stab-like in nature-psychological management demonstrated a remarkable ability to reduce/alleviate the more serious aspect of chronic orofacial pain and was deemed better in comparison to the rest. Lifestyle-based techniques and current stimulation-based management were of limited use since they tended to focus more on the causal and not the symptomatic aspect of orofacial pain.

Conclusions

Many patients with persistent orofacial discomfort can experience notable improvements in their symptoms and general well-being by all the treatment modalities evaluated.

Relationships among Inflammatory Biomarkers and Self-Reported Treatment-Related Symptoms in Patients Treated with Chemotherapy for Gynecologic Cancer: A Controlled Comparison

Previous research suggests that inflammation triggers cancer-treatment-related symptoms (i.e., fatigue, depression, and disruptions in sleep and physical activity), but evidence is mixed. This study examined relationships between inflammatory biomarkers and symptoms in patients with gynecologic cancer compared to age-matched women with no cancer history (i.e., controls). Patients (n = 121) completed assessments before chemotherapy cycles 1, 3, and 6, and 6 and 12 months later. Controls (n = 105) completed assessments at similar timepoints. Changes in inflammation and symptomatology were evaluated using random-effects mixed models, and cross-sectional differences between patients and controls in inflammatory biomarkers and symptoms were evaluated using least squares means. Associations among inflammatory biomarkers and symptoms were evaluated using random-effects fluctuation mixed models. The results indicated that compared to controls, patients typically have higher inflammatory biomarkers (i.e., TNF-alpha, TNFR1, TNFR2, CRP, IL-1ra) and worse fatigue, depression, and sleep (ps < 0.05). Patients reported lower levels of baseline physical activity (p = 0.02) that became more similar to controls over time. Significant associations were observed between CRP, depression, and physical activity (ps < 0.05), but not between inflammation and other symptoms. The results suggest that inflammation may not play a significant role in fatigue or sleep disturbance among gynecologic cancer patients but may contribute to depression and physical inactivity.

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

Elevated red blood cell distribution width levels predict depression after intracerebral hemorrhage: A 3-month follow-up study

Objectives

Inflammation vitally impacts the progression of depression resulting from intracerebral hemorrhage (ICH), while red blood cell distribution width (RDW) marks inflammatory-related diseases. The present study aimed at evaluating how RDW affects depression after ICH.

Methods

From prospective analyses of patients admitted to our department between January 2017 and September 2022, ICH patients with complete medical records were evaluated. The 17-item Hamilton Depression (HAMD-17) scale was used for measuring the depressive symptoms at 3 months after ICH. Diagnosis of post-ICH depression was conducted for patients based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria.

Results

A total of 438 patients were enrolled in the study, out of which 93 (21.23%) patients had PSD at the 3-month follow-up. Accordingly, patients with depression had higher RDW levels (13.70 [IQR: 13.56–13.89] vs.13.45 [IQR: 12.64–13.75], p &lt; 0.001) at admission compared with those without depression. In multivariate analyses, RDW was used for independently predicting the depression after ICH at 3 months (OR: 2.832 [95% CI: 1.748–4.587], p &lt; 0.001). After adjusting the underlying confounding factors, the odds ratio (OR) of depression after ICH was 4.225 (95% CI: 1.686–10.586, p = 0.002) for the highest tertile of RDW relative to the lowest tertile. With an AUC of 0.703 (95% CI: 0.649–0.757), RDW demonstrated a significantly better discriminatory ability relative to CRP and WBC. RDW as an indicator for predicting depression after ICH had an optimal cutoff value of 13.68, and the sensitivity and specificity were 63.4% and 64.6%, respectively.

Conclusions

Elevated RDW level predicted post-ICH depression at 3 months, confirming RDW as an effective inflammatory marker for predicting depression after ICH.

Dysbiosis of the Gut Microbiota and Kynurenine (Kyn) Pathway Activity as Potential Biomarkers in Patients with Major Depressive Disorder

With increasing attention paid to the concept of the microbiota-gut-brain axis, mounting evidence reveals that the gut microbiota is involved in a variety of neurological and psychiatric diseases. However, gut microbiota changes in major depressive disorder (MDD) patients and their association with disease mechanisms remain undefined. Fifty MDD patients and sixty healthy controls were recruited from the Shanghai Healthy Mental Center, China. Fecal samples were collected, and the compositional characteristics of the intestinal flora were determined in MDD patients by MiSeq sequencing. Venous blood was collected for the detection of plasma indoleamine-2,3-dioxygenase (Ido), kynurenine (Kyn) and tryptophan (Trp) levels. Stool samples of bacterial 16S sequencing was carried out. A total of 2,705,809 optimized sequences were obtained, with an average of 54,116 per sample. More unique OTUs were observed at the family, genus and species levels in the control group compared with the MDD cases. Further analysis showed significant changes in the α- and β-diversities and relative abundance levels of gut microbial entities in MDD patients, as well as elevated amounts of Ido and Kyn indicating Kyn pathway activation, KEGG bacterial 16S function prediction analysis shows a variety of amino acids and metabolic (including Ido, Trp and Kyn) changes in the body of patients with MDD. These may result in increased neurotoxic metabolites and reduced generation of serotonin in the disease process. These changed factors may potentially be utilized as biomarkers for MDD in the future, playing more important roles in the disease course.

Rheumatoid arthritis and the risk of postpartum psychiatric disorders: a Nordic population-based cohort study

BACKGROUND

Postpartum psychiatric disorders (PPD) are common complications of childbirth. A common explanation for their development is that the psychological, hormonal, and immune changes associated with pregnancy and parturition may trigger psychiatric symptoms postpartum. Rheumatoid arthritis (RA) is characterized by abnormalities in the activity of the hypothalamic-pituitary-adrenal axis and of the immune system, but its association with PPD is unknown. We analyzed whether women with RA before childbirth have an increased risk of PPD.

METHODS

We conducted a large population-based cohort study including mothers of singleton births in the Danish (1995-2015), Finnish (1997-2013), and Swedish Medical Birth Registers (2001-2013) (N = 3,516,849). We linked data from the Medical Birth Registers with data from several national socioeconomic and health registers. Exposure was defined as having a diagnosis of RA before childbirth, while the main outcome was a clinical diagnosis of psychiatric disorders 90 days postpartum. We analyzed the association between RA and PPD using Cox proportional hazard models, stratified by a personal history of psychiatric disorders.

RESULTS

Among women without a history of psychiatric disorders, the PPD incidence rate was 32.2 in the exposed and 19.5 per 1000 person-years in the unexposed group; women with RA had a higher risk of overall PPD than their unexposed counterparts [adjusted hazard ratio (HR) = 1.52, 95% confidence intervals (CI) 1.17 to 1.98]. Similar associations were also observed for postpartum depression (HR = 1.65, 95% CI 1.09 to 2.48) and other PPD (HR = 1.59, 95% CI 1.13 to 2.24). Among women with a history of psychiatric disorders, the incidence rate of overall PPD was 339.6 in the exposed and 346.6 per 1000 person-years in the unexposed group; RA was not associated with PPD. We observed similar associations between preclinical RA (RA diagnosed after childbirth) and PPD to those corresponding to clinical RA.

CONCLUSIONS

Rheumatoid arthritis was associated with an increased PPD risk in women without, but not in those with a psychiatric history. If our findings are confirmed in future studies, new mothers with RA may benefit from increased surveillance for new-onset psychiatric disorders postpartum.

Association between autoimmune diseases of the nervous system and schizophrenia: A systematic review and meta-analysis of cohort studies

INTRODUCTION

Numerous studies have found an association between autoimmune diseases of the nervous system (ADNS) and schizophrenia (SCZ), but the findings remain controversial. We conducted the first meta-analysis to summarize the current evidence from cohort studies that evaluated the association between ADNS and SCZ.

METHODS

PubMed, Web of Science, and Embase were comprehensively searched until May 30, 2022 for articles on the association between ADNS and SCZ. Every included study was reported effect size with 95% CIs for the association between ADNS and SCZ. Meta-regression and subgroup analysis were used to assess the heterogeneity.

RESULTS

A total of 8 cohort studies with 12 cohorts were included in the meta-analysis. We observed a significant association between ADNS and SCZ (RR = 1.42; 95%CI, 1.18-1.72). Subgroup analysis showed that the risk of SCZ was significantly increased when ADNS were used as exposure factors (RR = 1.48; 95%CI, 1.15-1.89), whereas with SCZ did not observe an increased risk of subsequent ADNS (RR = 1.33; 95%CI, 0.92-1.92); multiple sclerosis (MS) was positively associated with SCZ (RR = 1.36; 95%CI, 1.12-1.66), but no significant association was found between Guillain-Barre syndrome (GBS) and SCZ (RR = 1.90; 95%CI, 0.87-4.17). Meanwhile, we found location was the source of heterogeneity.

LIMITATIONS

High heterogeneity was observed (I² = 92.0%), and only English literature was included in the meta-analysis.

CONCLUSIONS

We found a positive association between ADNS and SCZ, and the association was different across the different types of ADNS. The results of the study are helpful for clinicians to carry out targeted preventive measures for ADNS and SCZ.

Effects of exercise training on inflammatory, neurotrophic and immunological markers and neurotransmitters in people with depression: A systematic review and meta-analysis

BACKGROUND

Major depressive disorder is the most common type of mental disorder. The biological pathway by which exercise promotes its antidepressant effects remains uncleared. This study aimed to systematically review the chronic effect of exercise on blood biomarkers and its association with changes in depressive symptoms in adults with major depressive disorder.

METHODS

Randomized controlled trials (RCT) published until February 2020 were screened in seven databases. Studies were systematically reviewed by two independent reviewers. Random effect meta-analysis was performed and reported as standardized mean differences (SMD) and 95 % confidence interval (CI). The meta- analysis protocol was registered with PROSPERO (CRD42021221177).

RESULTS

From 3865 records, 12 studies (N = 757 participants, mean age [SD]: 43.0 [11.0], 66.2 % women) were included in this review. Exercise training resulted in superior increase in circulating BDNF (SMD: 0.44, 95%CI: 0.15, 0.73) and kynurenine (SMD: 0.29, 95%CI: 0.04, 0.54), and decrease depressive symptoms (SMD: -0.72, 95%CI: -1.08, -0.37) in adults with major depression disorder compared to control groups. Multivariate meta-regression analysis showed that improvements in circulating levels of BDNF, kynurenine and interleukyn-6 were associated with decreases in depressive symptoms.

LIMITATIONS

Results were not stratified by the type of medication used by participants due to the lack of reporting of the included studies. Few studies provided data on other biomarkers (e.g., TNF-α and IL-10) besides BNDF and kynurenine.

CONCLUSIONS

Antidepressant effect of exercise may be triggered by improved circulating levels of BNDF, kynurenine, and interleukine-6 in adults with major depressive disorder.

Associations between the kynurenine pathway and the brain in patients with major depressive disorder-A systematic review of neuroimaging studies

Previous studies have indicated that an imbalance in the kynurenine (KYN) pathway is an important pathophysiological mechanism of depression. Several studies have reported that an imbalance in the KYN pathway and its metabolites is associated with abnormalities in cerebral structure and function in depression, but the available evidence has been inconsistent. In this review, we systematically reviewed and integrated the findings concerning the associations between the KYN pathway and the brain in patients with major depressive disorder (MDD). A total of 22 neuroimaging studies were ultimately included in the present study. The neuroimaging modalities used in the studies included structural magnetic resonance imaging (MRI), diffusion tensor imaging, functional MRI, magnetic resonance spectroscopy, arterial spin labelling and positron emission tomography. The results revealed that an imbalance in the KYN pathway was associated with structural and functional abnormalities in several brain regions in patients with MDD. The brain regions most frequently associated with an imbalance in the KYN pathway were cortical regions (i.e., anterior cingulate cortex and orbitofrontal cortex), subcortical regions (i.e., striatum, thalamus and amygdala) and white matter fibres (i.e., inner capsule and left superior longitudinal tract). Our study provides robust evidence that cerebral abnormalities associated with the KYN pathway may be the underlying pathophysiological mechanisms of MDD. Future prospective studies are needed to further elucidate the causal relationships between the imbalanced KYN pathway and cerebral abnormalities in patients with MDD.

The prevalence and the effect of interferon -γ in the comorbidity of rheumatoid arthritis and depression

BACKGROUND

Depression is the most common comorbidities associated with rheumatoid arthritis (RA). We aimed to explore the mechanism of association between RA and depression.

METHODS

120 subjects were enrolled and depression was diagnosed and assessed using DSM-5 and 24-item version of Hamilton Depression Scale. Pain intensity and joint function in patients with RA were assessed using the visual analog scale (VAS) and health assessment questionnaire (HAQ). Serum levels of interferon-gamma (IFN-γ), indoleamine 2,3-dioxygenase (IDO), kynurenine (KYN), tryptophan (TRP), and quinolinic acid (QUIN)were detected. In animal experiments, K/BxN mice with RA-like phenotype was used and depressive behavior was observed. The protein expression level of N-methyl -D- aspartate receptor 2B (NR2B) in the hippocampus was detected.

RESULTS

In this study, 36.67 % of patients with RA also had depression. The working status, month family income, tender joint count, the VAS and HAQ score were the main factors influencing the depression in RA patients. HAQ score was found to be an independent risk factor for depression in RA. Serum IDO, IFN-γ, KYN were increased and TRP contents were decreased in RA group. K/BxN mice with RA-like phenotype showed depressive behavior. However, injection of IFN-γ neutralizing antibody could inhibit kynurenine pathway and reverse the depressive behavior in mice. The levels of QUIN in the neurotoxic metabolic pathway were increased and N-methyl -D- aspartate receptors (NMDAR) were activated, which may be the mechanism behind the onset of depression.

CONCLUSIONS

From clinical and preclinical aspects, the occurrence of depression in RA was explored and the related mechanism was revealed.

Nanoparticulate MgH2 ameliorates anxiety/depression-like behaviors in a mouse model of multiple sclerosis by regulating microglial polarization and oxidative stress

Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system (CNS). Anxiety and depression are the most common psychiatric comorbidities of MS, which seriously affect patients' quality of life, treatment compliance, and prognosis. However, current treatments for anxiety and depression in MS show low therapeutic efficacy and significant side effects. In the present study, we explored the therapeutic effects of a novel low-toxic anti-inflammatory drug, nanoparticulate magnesium hydride (MgH₂), on mood disorders of MS. We observed that anxiety/depression-like behaviors in experimental autoimmune encephalomyelitis (EAE) mice were alleviated by MgH₂ treatment. In addition, disease severity and inflammatory demyelination were also diminished. Furthermore, we confirmed the suppressive effect of MgH₂ on depression in the acute restraint stress model. Mechanistically, MgH₂ may play a therapeutic role by promoting microglial M2 polarization, inhibiting microglial M1 polarization, and reducing oxidative stress and mitochondrial damage. Therefore, nanoparticulate MgH₂ may be a promising therapeutic drug for psychiatric comorbidities of MS.

Serum serotonin levels are elevated in patients with increased risk of rheumatoid arthritis

Background

Even though serotonin (5-HT) has been ascribed immunomodulatory features, very little is known about its role in chronic inflammatory diseases. Serotonin is implicated in inflammation and increased levels have been associated with progression of bone erosions in RA.

Objective

To investigate serum serotonin levels in patients with increased risk of rheumatoid arthritis (RA) and patients with recent-onset disease. Moreover, we aimed to determine the prognostic value of serotonin for arthritis development and the disease course.

Methods

Two prospective observational patient cohorts were studied; anti-citrullinated protein antibody (ACPA) -positive patients with musculoskeletal pain without clinical arthritis (n = 82) and patients with early RA (n = 412). Serotonin levels were measured by enzyme-linked immunosorbent assay (ELISA) in baseline serum samples from both cohorts, and longitudinally in at-risk individuals.

Results

Compared to healthy controls (median 65 ng/ml), serotonin levels were significantly higher in both at-risk individuals (median 111 ng/ml, p < 0.0001) and patients with early RA (median 135 ng/ml, p < 0.0001). No significant differences were found between at-risk individuals and patients with early RA. At-risk individuals progressing to arthritis had similar levels as those not progressing, and no significant differences were seen over time. Baseline levels in early RA did not associate with mean 28-joint disease activity scores during 3 years follow-up.

Conclusion

Serum serotonin levels are elevated both at, and prior to, onset of RA. However, increased serotonin is not prognostic for arthritis development or disease course.

Elevated Serum IL-2 Levels are Associated With Major Depressive Disorder: A Case-Control Study

Objectives

Numerous earlier studies have stated an association between major depressive disorder (MDD) and altered expression of inflammatory process. However, it still needs to determine whether the alteration of cytokines is the causative factor or a consequence of this disorder. Therefore, we attempted to evaluate the role of the pro-inflammatory cytokine IL-2 in the pathophysiology of depression.

Methods

We collected blood samples from 111 MDD patients and 112 healthy controls (HCs) matched by age and sex. Diagnostic and statistical manual of mental disorders (DSM-5) score was used to assess study participants. We determined the severity of depression using the Hamilton Depression (Ham-D) rating scale. We assayed serum levels of IL-2 using the Enzyme-Linked Immunosorbent Assay (ELISA) kit.

Results

Elevated levels of IL-2 were detected in MDD patients than HCs (29.79 ± 6.18 and 12.77 ± 4.84 pg/ml, P < 0.05). We observed a higher level of IL-2 in female MDD patients compared to female HCs (31.98 ± 8.34 and 7.76 ± 0.36 pg/ml, P < 0.05). We witnessed a sex-specific correlation between the serum IL-2 levels and the Ham-D score and found that the females with higher Ham-D scores had higher serum IL-2 levels. Moreover, the ROC curve represented the good diagnostic performance of serum IL-2 levels as a biomarker with sensitivity and specificity values of 83.7% and 80.4%, respectively.

Conclusions

The current study findings indicate that elevated serum IL-2 levels are associated with MDD. This alteration may be the cause of triggering depression or a result of the activated inflammatory process during the depression. Therefore, we recommend further interventional research to clarify the actual reasons for these altered IL-2 levels in MDD patients.

[Psychosomatic medicine: old resources and new technologies]

Two primary research directions closely coexist in psychosomatic medicine. One is the most traditional, associated with an assessment of the psychological aspects of the connection, interconnection and mutual impact of mental and somatic pathology. The second, based on the rapid development of biological medicine in the last decade, studies causal associations and looks for shared mechanisms. In our review, we consider the previous main stages in the psychosomatic medicine and the prospective approaches to its further study. Evaluation of the etiopathogenesis of the entire set of mental and somatic symptoms in their interaction and dynamics can help identify individual subpopulations of patients with shared pathobiochemical and neurophysiological disorders. The recent interpretation of the biopsychosocial model is mainly related to the etiology and pathogenesis of mental disorders and also provides a good perspective for research on these issues. Today, there are sufficient opportunities to study all three domains of the model. Productive study of the biological, personal and social domains is also possible on the base of evidence-based design using modern research technologies.

The Glutamatergic System in Treatment-Resistant Depression and Comparative Effectiveness of Ketamine and Esketamine: Role of Inflammation?

The glutamatergic system is the primary excitatory pathway within the CNS and is responsible for cognition, memory, learning, emotion, and mood. Because of its significant importance in widespread nervous system function, it is tightly regulated through multiple mechanisms, such as glutamate recycling, microglial interactions, and inflammatory pathways. Imbalance within the glutamatergic system has been implicated in a wide range of pathological conditions including neurodegenerative conditions, neuromuscular conditions, and mood disorders including depression. Major depressive disorder (MDD) is the most common mood disorder worldwide, has a high prevalence rate, and afflicts approximately 280 million people. While there are numerous treatments for the disease, 30-40% of patients are unresponsive to treatment and deemed treatment resistant; approximately another third experience only partial improvement (World Health Organization, Depression fact sheet [Internet], 2020). Esketamine, the S-enantiomer of ketamine, was approved by the Food and Drug Administration for treatment-resistant depression (TRD) in 2019 and has offered new hope to patients. It is the first treatment targeting the glutamatergic system through a complex mechanism. Numerous studies have implicated imbalance in the glutamatergic system in depression and treatment resistance. Esketamine and ketamine principally work through inhibition of the NMDA receptor, though more recent studies have implicated numerous other mechanisms mediating the antidepressant efficacy of these agents. These mechanisms include increase in brain-derived neurotrophic factor (BDNF), activation of mammalian target of the rapamycin complex (mTORC), and reduction in inflammation. Esketamine and ketamine have been shown to decrease inflammation in numerous ways principally through reducing pro-inflammatory cytokines (e.g., TNF-α, IL-6) (Loix et al., Acta Anaesthesiol Belg 62(1):47-58, 2011; Chen et al., Psychiatry Res 269:207-11, 2018; Kopra et al., J Psychopharmacol 35(8):934-45, 2021). This anti-inflammatory effect has also been shown to be involved in the antidepressive properties of both ketamine and esketamine (Chen et al., Psychiatry Res 269:207-11, 2018; Kopra et al., J Psychopharmacol 35(8):934-45, 2021).

The role of indoleamine 2,3-dioxygenase 1 in early-onset post-stroke depression

Background

The immune-inflammatory response has been widely considered to be involved in the pathogenesis of post-stroke depression (PSD), but there is ambiguity about the mechanism underlying such association.

Methods

According to Diagnostic and Statistical Manual of Mental Disorders (5th edition), depressive symptoms were assessed at 2 weeks after stroke onset. 15 single nucleotide polymorphisms (SNPs) in genes of indoleamine 2,3-dioxygenase (IDO, including IDO1 and IDO2) and its inducers (including pro-inflammatory cytokines interferon [IFN]-γ, tumor necrosis factor [TNF]-α, interleukin [IL]-1β, IL-2 and IL-6) were genotyped using SNPscan™ technology, and serum IDO1 levels were detected by double-antibody sandwich enzyme-linked immune-sorbent assay.

Results

Fifty-nine patients (31.72%) were diagnosed with depression at 2 weeks after stroke onset (early-onset PSD). The IDO1 rs9657182 T/T genotype was independently associated with early-onset PSD (adjusted odds ratio [OR] = 3.008, 95% confidence interval [CI] 1.157-7.822, p = 0.024) and the frequency of rs9657182 T allele was significantly higher in patients with PSD than that in patients with non-PSD (χ2 = 4.355, p = 0.037), but these results did not reach the Bonferroni significance threshold (p > 0.003). Serum IDO1 levels were also independently linked to early-onset PSD (adjusted OR = 1.071, 95% CI 1.002-1.145, p = 0.044) and patients with PSD had higher serum IDO1 levels than patients with non-PSD in the presence of the rs9657182 T allele but not homozygous C allele (t = -2.046, p = 0.043). Stroke patients with the TNF-α rs361525 G/G genotype had higher serum IDO1 levels compared to those with the G/A genotype (Z = -2.451, p = 0.014).

Conclusions

Our findings provided evidence that IDO1 gene polymorphisms and protein levels were involved in the development of early-onset PSD and TNF-α polymorphism was associated with IDO1 levels, supporting that IDO1 which underlie strongly regulation by cytokines may be a specific pathway for the involvement of immune-inflammatory mechanism in the pathophysiology of PSD.

Potential diagnostic markers and therapeutic targets for rheumatoid arthritis with comorbid depression based on bioinformatics analysis

Background

Rheumatoid arthritis (RA) and depression are prevalent diseases that have a negative impact on the quality of life and place a significant economic burden on society. There is increasing evidence that the two diseases are closely related, which could make the disease outcomes worse. In this study, we aimed to identify diagnostic markers and analyzed the therapeutic potential of key genes.

Methods

We assessed the differentially expressed genes (DEGs) specific for RA and Major depressive disorder (MDD) and used weighted gene co-expression network analysis (WGCNA) to identify co-expressed gene modules by obtaining the Gene expression profile data from Gene Expression Omnibus (GEO) database. By using the STRING database, a protein-protein interaction (PPI) network constructed and identified key genes. We also employed two types of machine learning techniques to derive diagnostic markers, which were assessed for their association with immune cells and potential therapeutic effects. Molecular docking and in vitro experiments were used to validate these analytical results.

Results

In total, 48 DEGs were identified in RA with comorbid MDD. The PPI network was combined with WGCNA to identify 26 key genes of RA with comorbid MDD. Machine learning-based methods indicated that RA combined with MDD is likely related to six diagnostic markers: AURKA, BTN3A2, CXCL10, ERAP2, MARCO, and PLA2G7. CXCL10 and MARCO are closely associated with diverse immune cells in RA. However, apart from PLA2G7, the expression levels of the other five genes were associated with the composition of the majority of immune cells in MDD. Molecular docking and in vitro studies have revealed that Aucubin (AU) exerts the therapeutic effect through the downregulation of CXCL10 and BTN3A2 gene expression in PC12 cells.

Conclusion

Our study indicates that six diagnostic markers were the basis of the comorbidity mechanism of RA and MDD and may also be potential therapeutic targets. Further mechanistic studies of the pathogenesis and treatment of RA and MDD may be able to identify new targets using these shared pathways.

Toward Elucidating the Human Gut Microbiota-Brain Axis: Molecules, Biochemistry, and Implications for Health and Diseases

In recent years, a substantial amount of data have supported an active role of gut microbiota in mediating mammalian brain function and health. Mining gut microbiota and their metabolites for neuroprotection is enticing but requires that the fundamental biochemical details underlying such microbiota-brain crosstalk be deciphered. While a neuronal gut-brain axis (through the vagus nerve) is not disputable, accumulating studies also point to a humoral route (via blood/lymphatic circulation) by which innumerable microbial molecular cues translocate from local gut epithelia to circulation with potentials to further cross the blood-brain barrier and reach the brain. In this Perspective, we review a realm of gut microbial molecules to evaluate their fate, function, and neuroactivities in vivo as mediated by microbiota. We turn to seminal studies of neurophysiology and neurologic disease models for the elucidation of biochemical pathways that link microbiota to gut-brain signaling. In addition, we discuss opportunities and challenges for advancing the microbiota-brain axis field while calling for high-throughput discovery of microbial molecules and studies for resolving the interspecies, interorgan, and interclass interaction among these neuroactive microbial molecules.