Patients with depression display cytokine levels in serum and cerebrospinal fluid similar to patients with diffuse neurological symptoms without a defined diagnosis

A comprehensive analysis of the differential expression in the hippocampus of depression induced by gut microbiota compared to traditional stress

Depression, which is a disease of heterogeneous etiology, is characterized by high disability and mortality rates. Gut microbiota are associated with the development of depression. To further explore any differences in the mechanisms of depression induced by gut microbiota and traditional stresses, as well as facilitate the development of microbiota-based interventions, a fecal microbiota transplantation (FMT) depression model was made. This was achieved by transplanting feces from major depressive disorder (MDD) patients into germ-free mice. Second, the mechanisms of the depression induced by gut microbiota were analyzed in comparison with those of the depression caused by different forms of stress. It turned out that mice exhibited depressive-like behavior after FMT. Then, PCR array analysis was performed on the hippocampus of the depressed mice to identify differentially expressed genes (DEGs). The KEGG analysis revealed that the pathways of depression induced by gut microbes are closely associated with immuno-inflammation. To determine the pathogenic pathways of physiological stress and psychological stress-induced depression, raw data was extracted from several databases and KEGG analysis was performed. The results from the analysis revealed that the mechanisms of depression induced by physiological and psychological stress are closely related to the regulation of neurotransmitters and energy metabolism. Interestingly, the immunoinflammatory response was distinct across different etiologies that induced depression. The findings showed that gut microbiota dysbiosis-induced depression was mainly associated with adaptive immunity, while physiological stress-induced depression was more linked to innate immunity. This study compared the pathogenesis of depression caused by gut microbiota dysbiosis, and physiological and psychological stress. We explored new intervention methods for depression and laid the foundation for precise treatment.

Current trends and hotspots of depressive disorders with colorectal cancer: A bibliometric and visual study

BACKGROUND

Depression is strongly associated with colorectal cancer (CRC). Few bibliometric analyses have systematically summarized the research focus and recent progress in this field.

AIM

To determine the research status and hotspots by bibliometric analysis of relevant publications on the relationship between CRC and depression.

METHODS

Articles on depression in CRC patients were collected from the Web of Science Core Collection. CiteSpace and VOSviewer software were used to visualize bibliometric networks.

RESULTS

From 2001 to 2022, Supportive Care in Cancer, the United States, Tilburg University, and Mols were the most productive and influential journal, country, institution, and author name. Co-occurrence cluster analysis of keywords placed quality of life, anxiety, and psychological stress in the center of the visual network diagram. Further clustering was performed for the clusters with studies of the relevant mechanism of action, which showed that: (1) Cytokines have a role essential for the occurrence and development of depressive disorders in CRC; (2) MicroRNAs have a role essential for the development of depressive disorders in CRC; (3) Some anticancer drugs have pro-depressant activity; and (4) Selective serotonin reuptake inhibitors have both antitumor and antidepressant activity.

CONCLUSION

Life quality and psychological nursing of the cancer population were key topics. The roles of cytokines and microRNAs, the pro-depression activity of anticancer drugs and their antitumor properties deserve in-depth study.

Search for cerebrospinal fluid biomarkers in patients with major psychiatric disorders: Multiplex immunoassay findings and proximity extension assay prospects

Multiplex immunoassays have been developed to detect multiple proteins simultaneously and are used to search for biomarkers, including those present in major psychiatric disorders. This study aimed to review multiplex immunoassay studies on cerebrospinal fluid (CSF) biomarkers in patients with schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD) and examine future research directions using improved proteomic techniques. According to the results of previous multiplex immunoassay studies, increased CSF IFN-β, IL-8, MCP-2, MMP-2, PAI-1, sICAM-1, and sVCAM-1 and decreased CSF ACE, APP, fibrinogen, and GDNF were observed in patients with schizophrenia, while CSF HGF and S100B were positively correlated with psychotic symptom and CSF IL-11, IL-29/IFN-λ1, and TSLP were negatively correlated. Increased CSF IFN-β and IL-1β and decreased CSF Aβ42, APP, IL-6, and NCAM-1 were observed, while CSF S100B was positively correlated with manic symptom in patients with BD. Increased CSF IL-4, MCP-1, MIP-1β, and MMP-2 were observed in patients with MDD, while CSF HGF and MMP-2 were positively correlated with depressive symptom and CSF IL-15 and MCP-1 were negatively correlated. However, signal cross-talk and cross-reactivity problems have been observed in previous studies using multiplex immunoassay. The proximity extension assay can be used to overcome cross-reactivity and enable ultrasensitive multiplexed detection and quantification of more than 1000 target proteins. However, proteomic studies using proximity extension assay technology in patients with schizophrenia, BD, or MDD are still scarce. Therefore, future high-quality proteomic studies are required to identify CSF biomarkers for larger sets of target proteins in patients with major psychiatric disorders.

Association of Long-Term HbA1c Variability with Anxiety and Depression in Patients with Type 2 Diabetes: A Cross-Sectional Retrospective Study

Purpose

To explore the relationship between long-term glycemic variability and anxiety and depression in patients with type 2 diabetes.

Participants and Methods

A cohort comprising 214 individuals diagnosed with type 2 diabetes participated in this study. Comprehensive demographic and laboratory information was gathered for them. The evaluation of anxiety relied on the 7-item Generalized Anxiety Disorder Scale (GAD-7), while depression was assessed utilizing the 9-item Health Questionnaire (PHQ-9). Based on the presence or absence of anxiety and depression, participants were categorized into either the mood disorder or control groups. Subsequently, univariate and stepwise multiple binary logistic regression analyses were conducted to investigate the potential correlations between factors and the presence of anxiety and depression.

Results

The prevalence of anxiety disorders is 23%, and depression is 32%. The prevalence of smoking, diabetic autonomic neuropathy, stroke, and osteoporosis in the mood disorder group was significantly higher than that in the control group (P < 0.05), the glycated hemoglobin A1c variability score (HVS), mean hemoglobin A1c value, total cholesterol, urinary albumin/creatinine and systemic immune-inflammatory index (SII) were significantly higher in the control group (P < 0.05). The level of high-density lipoprotein in the mood disorder group was significantly lower than the control group (P < 0.05). In stepwise multiple binary logistic regression analyses, the main factors associated with anxiety were depression (P < 0.001, OR=117.581) and gender (P < 0.001, OR=9.466), and the main factors related to depression included anxiety (P < 0.001, OR=49.424), smoking (P=0.042, OR=2.728), HVS (P=0.004, OR=8.664), and SII (P=0.014, OR=1.002).

Conclusion

Persistent fluctuations in blood glucose levels have been linked to anxiety and depression. Consequently, maintaining an optimal level of glycemic control and minimizing fluctuations becomes imperative in the comprehensive management of diabetes.

APOE Polymorphism Is Associated with Changes in the Kynurenine Pathway

BACKGROUND

APOE polymorphism and the Kynurenine pathway (KP) are associated with many disorders, but little is known about associations between APOE polymorphism and the KP. This study explored the associations between the KP and APOE polymorphism in disorders associated with APOE polymorphism and changes in the KP.

METHODS

Subjects with morbid obesity before and after bariatric surgery (numbers 139 and 95, respectively), depression (number 49), and unspecified neurological symptoms (number 39) were included. The following grouping of the APOE genotypes was used: E2 = ɛ2ɛ2 + ɛ2ɛ3, E3 = ɛ3ɛ3 + ɛ2ɛ4, and E4 = ɛ3ɛ4 + ɛ4ɛ4. The KP metabolites Tryptophan, Kynurenine, Kynurenic acid, Quinolinic acid, and Xanthurenic acid were quantified in serum.

RESULTS

The main findings were a significant positive association between E3 and Quinolinic acid (difference between E3 and E2E4: 12.0 (3.5; 18.6) ng/mL); p = 0.005), and a negative association between E4 and Kynurenine (difference between E4 and E2E3: -31.3 (-54.2; -3.2) ng/mL; p = 0.008). Quinolinic acid has been ascribed neurotoxic and inflammatory effects, and Kynurenine is a marker of inflammation.

CONCLUSIONS

The findings indicate that APOE polymorphism might cause changes in the KP that contribute to the disease. Inflammation could be the link between APOE and the KP.

Cytokine alterations in CSF and serum samples of patients with a first episode of schizophrenia: results and methodological considerations

We determined cytokine levels in paired serum/CSF samples from first-episode schizophrenia (FES) participants (n = 20) and controls (n = 21) using a 13-plex immunoassay. Applying strictly-determined detection limits, 12 cytokines were found in serum and two in CSF. Higher serum MCP-1 levels (p = 0.007) were present in FES versus controls, which correlated with serum IgG (R = - 0.750; p = 0.013). Finally, IL-18 levels correlated with body weight in FES (R = 0.691; p = 0.041). This study demonstrates potential limitations in the sensitivity of multiplex cytokine assays for CSF studies in mental disorders and suggests that some published studies in this area should be re-evaluated.

Repeated Social Defeat Stress Induces HMGB1 Nuclear Export in Prefrontal Neurons, Leading to Social Avoidance in Mice

Inflammation has been associated with depression, and innate immune receptors, such as the Toll-like receptor (TLR) 2/4 in the medial prefrontal cortex (mPFC), are crucial for chronic stress-induced depression-related behaviors in mice. HMGB1, a putative ligand for TLR2/4, has been suggested to promote depression-related behaviors under acute stress. However, the roles of endogenous HMGB1 under chronic stress remain to be investigated. Here, we found that the cerebroventricular infusion of HMGB1 proteins blocked stress-induced social avoidance and that HMGB1-neutralizing antibodies augmented repeated social defeat stress-induced social avoidance in mice, suggesting the antidepressive-like effect of HMGB1 in the brain. By contrast, the infusion of HMGB1-neutralizing antibodies to the mPFC and HMGB1 knockout in α-CaMKII-positive forebrain neurons attenuated the social avoidance, suggesting the pro-depressive-like effect of HMGB1 released from prefrontal neurons under chronic stress. In addition, repeated social defeat stress induced HMGB1 nuclear export selectively in mPFC neurons, which was abolished in the mice lacking RAGE, one of HMGB1 receptors, suggesting the positive feedback loop of HMGB1-RAGE signaling under chronic stress. These findings pave the way for identifying multiple roles of HMGB1 in the brain for chronic stress and depression.

Comparisons of 25 cerebrospinal fluid cytokines in a case-control study of 106 patients with recent-onset depression and 106 individually matched healthy subjects

BACKGROUND

Neuroinflammation has been suggested as a contributor to the pathophysiology of depression; however, large case-control studies investigating cytokine levels in the cerebrospinal fluid (CSF) from patients with recent-onset depression by multiplex analyses are missing.

METHODS

An individually matched (sex and age) prospective case-control study comparing patients with recent-onset depression to healthy controls. CSF was analyzed with the Mesoscale V-PLEX Neuroinflammation Panel 1.

OUTCOMES

comparisons of analyte levels in the CSF between groups with interleukin (IL)-6 and IL-8 as primary outcomes and 23 other cytokines as secondary outcomes.

RESULTS

We included 106 patients (84.0% outpatients) with recent-onset depression and 106 healthy controls. There were no significant differences in the primary outcomes IL-6 (relative mean difference (MD): 1.10; 95% confidence interval (CI) 0.93-1.30; p = 0.276) or IL-8 levels (MD: 1.05; 95% CI 0.96-1.16; p = 0.249) relative to healthy controls. IL-4 was 40% higher (MD: 1.40; 95% CI 1.14-1.72; p = 0.001), monocyte chemoattractant protein (MCP)-1 was 25% higher (MD: 1.25; 95% CI 1.06-1.47; p = 0.009) and macrophage inflammatory protein (MIP)-1β was 16% higher (MD: 1.16; 95% CI 1.02-1.33; p = 0.025) in patients with depression relative to healthy controls. However, only IL-4 was significantly elevated after correction for multiple testing of secondary outcomes (p = 0.025).

CONCLUSION

We found no significant differences in CSF levels of the co-primary outcomes IL-6 and IL-8, however, the higher CSF levels of IL-4, MCP-1 and MIP-1β among patients with recent-onset depression compared to healthy controls indicate a potential role of these cytokines in the neuroinflammatory response to depression.

Hyper-inflammation of astrocytes in patients of major depressive disorder: Evidence from serum astrocyte-derived extracellular vesicles

Astrocyte-derived extracellular vesicles (ADEs) allow the in vivo probing of the inflammatory status of astrocytes practical. Serum sample and ADEs were used to test the inflammatory hypothesis in 70 patients with major depressive disorder (MDD) and 70 matched healthy controls (HCs). In serum, tumor necrosis factor α (TNF-α) and interleukin (IL)-17A were significantly increased, where as IL-12p70 was significantly reduced in the MDD patients compared with HCs. In ADEs, all inflammatory markers (Interferon-γ, IL-12p70, IL-1β, IL-2, IL-4, IL-6, TNF-α, and IL-17A) except IL-10 were significantly increased in the MDD patients, the Hedge's g values of elevated inflammatory markers varied from 0.48 to 1.07. However, there were no differences of all inflammatory markers whether in serum or ADEs between MDD-drug free and medicated subgroups. The association of inflammatory biomarkers between ADEs and serum did not reach statistically significance after multi-comparison correction neither in the HCs nor MDD patients. The spearman coefficients between inflammatory factors and clinical characteristics in the MDD patients, such as onset age, disease course, current episode duration, and severity of depression, were nonsignificant after multi-comparison correction. In the receiver operating characteristic curves analysis, the corrected partial area under the curve (pAUC) of each inflammatory markers in ADEs ranged from 0.522 to 0.696, and the combination of these inflammatory factors achieved a high pAUC (>0.9). Our findings support the inflammatory glial hypothesis of depression, and suggests that in human ADEs could be a useful tool to probe the in vivo astrocyte status.

The Impact of Various Methods of Obesity Treatment on the Quality of Life and Mental Health-A Narrative Review

Obesity, defined as body mass index (BMI) ≥ 30 kg/m², is one of the most important public health problems. Over one billion people are obese, including 650 million adults, which is 13% of the worldwide population, according to the World Health Organization (WHO). Similar to obesity, mental disorders such as depression and anxiety are huge social problems with serious health implications. There are numerous studies proving a strong link between the prevalence of obesity and depressive disorders, and being overweight is also associated with decreased health-related quality of life (HRQoL). Due to the broad negative impact of obesity on a patient's health, proper treatment is crucial. Currently, the literature describes many methods of treatment such as dietary treatment, pharmacotherapy using glucagon-like peptide-1 (GLP-1) analogs, orlistat, naltrexone/bupropion (NB), or finally bariatric surgery. The most commonly used methods of obesity treatment significantly improve the patient's quality of life and reduce the symptoms of depression and anxiety. The aim of our study was to summarize the knowledge about the impact of known and commonly used methods of obesity treatment (e.g., dietary treatment, bariatric surgery, and pharmacological treatment) on mental health and quality of life. For this purpose, we will try to review the current scientific data, originating from international reports.

Binge eating disorder, frequency of depression, and systemic inflammatory state in individuals with obesity - A cross sectional study

Introduction

Binge eating disorder (BED) is the most prevalent eating disorder in individuals with obesity. Its association with factors that control hunger and satiety has not yet been elucidated. We evaluated whether levels of inflammatory markers, frequency of psychiatric comorbidities, and appetite-related hormones levels differ between individuals with obesity with and without BED.

Subjects and methods

The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-5 - Clinician Version (SCID-5-CV), Binge Eating Scale, and Hospital Anxiety and Depression Scale were evaluated in 39 individuals with obesity. Plasma levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), leptin, ghrelin, and glucagon-like peptide-1 (GLP-1) were measured.

Results

Individuals of the BED group exhibited significantly higher percentages of altered eating patterns (hyperphagia, bingeing, post-dinner eating, feeling "stuffed", and emotional eating), higher depressive symptom scores and levels of leptin, CRP, and TNF-α, compared to those from the non-BED group. Logistic regression showed that BED was independently associated with depressive symptoms and CRP levels.

Conclusion

Individuals with obesity and BED showed greater psychiatric comorbidity, worse eating patterns and worse inflammatory profile than those without BED. BED should be assessed as an indicator of clinical severity in patients with obesity.

Cerebrospinal fluid cytokines in geriatric patients with depressive disorders: A retrospective case-control study

Central nervous system inflammation might play a role in patients with depressive disorders. This hypothesis is supported by studies reporting increased cerebrospinal fluid levels of the inflammatory markers interleukin (IL)-6, IL-8 and tumor necrosis factor alpha (TNF-α) in patients with ongoing depression. In this case-control study, we aimed to examine whether these findings also applied to depressed patients in a geriatric population. Cerebrospinal fluid cytokine analyses were performed on 15 patients (age >60 years) with depressive disorders and 45 age- and sex matched controls (patients with headache or idiopathic facial palsy). IL-6, IL-8, IL-10, TNF-α, monocyte chemoattractant protein-1 and transforming growth factor beta 1 were included in the statistical analyses. Patients with depression had significantly lower cerebrospinal fluid levels of IL-6 as compared to controls (p = 0.014) in the univariate analysis. The finding was, however, no longer statistically significant after correction for age and body mass index (p = 0.097). Overall, this study indicates that the cytokines included in this study are not significantly altered in geriatric patients with depression. Future studies exploring cerebrospinal fluid cytokine levels should include corrections for possible confounding factors.

Inflammatory Pre-Conditioning of Adipose-Derived Stem Cells with Cerebrospinal Fluid from Traumatic Brain Injury Patients Alters the Immunomodulatory Potential of ADSC Secretomes

Immunomodulation by adipose-tissue-derived stem cells (ADSCs) is of special interest for the alleviation of damaging inflammatory responses in central nervous system injuries. The present study explored the effects of cerebrospinal fluid (CSF) from traumatic brain injury (TBI) patients on this immunomodulatory potential of ADSCs. CSF conditioning of ADSCs increased messenger RNA levels of both pro- and anti-inflammatory genes compared to controls. Exposure of phorbol-12-myristate-13-acetate-differentiated THP1 macrophages to the secretome of CSF-conditioned ADSCs downregulated both proinflammatory (cyclooxygenase-2, tumor necrosis factor alpha) and anti-inflammatory (suppressor of cytokine signaling 3, interleukin-1 receptor antagonist, and transforming growth factor beta) genes in these cells. Interleukin-10 expression was elevated in both naïve and conditioned secretomes. ADSC secretome treatment, further, induced macrophage maturation of THP1 cells and increased the percentage of CD11b⁺, CD14⁺, CD86⁺, and, to a lesser extent, CD206⁺ cells. This, moreover, enhanced the phagocytic activity of CD14⁺ and CD86⁺ cells, though independently of pre-conditioning. Secretome exposure, finally, also induced a reduction in the percentage of CD192⁺ adherent cells in cultures of peripheral blood mononuclear cells (PBMCs) from both healthy subjects and TBI patients. This limited efficacy (of both naïve and pre-conditioned secretomes) suggests that the effects of lymphocyte-monocyte paracrine signaling on the fate of cultured PBMCs are strongest upon adherent cell populations.

Ketogenic Diet Therapy for Intractable Epilepsy in Infantile Alexander Disease: A Small Case Series and Analyses of Astroglial Chemokines and Proinflammatory Cytokines

In infantile Alexander disease (iAxD), one of the serious symptoms is intractable epilepsy, and some reports have suggested that neuroinflammation may be involved in the pathophysiology of the disease. Drug-resistant seizures adversely affect not only the quality of life of the caregivers and patients, but also patients' lifespan. Thus, controlling epilepsy is clinically important. For intractable childhood epilepsy, ketogenic diet therapy (KDT) is well-established, but its effects on iAxD have not been characterized. Here, we describe the use of KDT in three iAxD patients experiencing drug-resistant seizures. In all three cases, the formerly intractable epilepsies were well controlled by KDT. However, the brain magnetic resonance imaging findings deteriorated even after the epilepsy was controlled. In addition, the concentrations of monocyte chemotactic protein-1 and proinflammatory cytokines in the cerebrospinal fluid of the patients remained still high. KDT is effective in controlling epilepsy in iAxD. Our results clinically support previous reports arguing the involvement of neuroinflammation in the pathophysiology of iAxD.　Although KDT cannot prevent disease progression, earlier initiation might contribute to a better prognosis.

Alleviation of Depression by Glucagon-Like Peptide 1 Through the Regulation of Neuroinflammation, Neurotransmitters, Neurogenesis, and Synaptic Function

Depression has emerged as a major cause of mortality globally. Many studies have reported risk factors and mechanisms associated with depression, but it is as yet unclear how these findings can be applied to the treatment and prevention of this disorder. The onset and recurrence of depression have been linked to diverse metabolic factors, including hyperglycemia, dyslipidemia, and insulin resistance. Recent studies have suggested that depression is accompanied by memory loss as well as depressive mood. Thus, many researchers have highlighted the relationship between depressive behavior and metabolic alterations from various perspectives. Glucagon-like peptide-1 (GLP-1), which is secreted from gut cells and hindbrain areas, has been studied in metabolic diseases such as obesity and diabetes, and was shown to control glucose metabolism and insulin resistance. Recently, GLP-1 was highlighted as a regulator of diverse pathways, but its potential as the therapeutic target of depressive disorder was not described comprehensively. Therefore, in this review, we focused on the potential of GLP-1 modulation in depression.

Pro- and anti-inflammatory properties of interleukin (IL6) in vitro: relevance for major depression and for human hippocampal neurogenesis

BACKGROUND

Although the pro-inflammatory cytokine, interleukin (IL)6, has been generally regarded as "depressogenic", recent research has started to question this assumption, in light of the fact that this cytokine can also have anti-inflammatory properties. This bimodal action seems to be dependent on its concentration levels, and on the concomitant presence of other pro-inflammatory cytokines.

METHODS

We exposed a human hippocampal progenitor cell line HPC0A07/03C to cytokine levels described in depressed patients (IL6 5pg/ml with IL1β 10pg/ml or Macrophage Migration Inhibitory Factor (MIF) 300pg/ml), in healthy subjects (IL6 with IL1β, 1pg/ml or MIF 10pg/ml), as well as to the potentially anti-inflammatory, much higher concentrations of IL6 (50000pg/ml).

RESULTS

Treatment with high concentrations of IL6 with IL1β or MIF (resembling depressed patients) decreases neurogenesis when compared with low concentrations of the same cytokines (healthy subjects), and that this is mediated via production of, respectively, IL8 and IL1β in cell supernatant. Instead, treatment with the very high, anti-inflammatory concentration of IL6 (50000pg/ml) together with high IL1β or MIF prevents the decrease in neurogenesis and reduces both IL8 and IL1β. When the high concentrations of both IL1β and MIF were used in co-treatment, as a model of treatment resistant depression, we also demonstrate a reduction in neurogenesis, and that this is mediated via a decrease in IL4; moreover, co-treatment with high IL1β and MIF and the very high concentration of IL6 prevents the reduction in neurogenesis, and increases IL4.

CONCLUSIONS

Our results demonstrate that IL6 can exert both pro- and anti-inflammatory (potentially antidepressant) properties, depending on its concentrations and combinations with other inflammatory cytokines.

C-reactive protein and clinical subtypes of major depressive disorder at Zagazig University Hospitals

Background

Although, the relation between inflammation and major depressive disorder (MDD) looks like firm, it may not exist in all patients with depression. Therefore, the main aim of this study was to compare serum C-reactive protein (CRP) level among clinical subtypes of MDD and its relation with suicidality.

Results

According to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for MDD, 98 patients included and categorized into five clinical subtypes groups: atypical, anxious, melancholic, psychotic, and unspecified depression with percent (11.2%, 31.6%, 19.4%, 15.3%, and 22.4%) respectively. Twenty-four (24.5%) of all patients had suicidal thoughts using Beck Scale for Suicidal Ideation (BSS) with statistically significant increase (P < 0.05*) in suicidality among atypical group. On assessing CRP level, there was highly statistical significant increase (P < 0.001**) among cases with atypical type and also cases with suicidal ideation. Also, logistic regression analysis found that the significant predictors for high CRP among the studied cases were smoking, suicidality, atypical depression, and suicide depression.

Conclusions

Higher level of CRP was found among patients with atypical MDD, and there was significant relationship between CRP and suicidality.

Agitation, Oxidative Stress, and Cytokines in Alzheimer Disease: Biomarker Analyses From a Clinical Trial With Nabilone for Agitation

The endocannabinoid system has been a target of interest for agitation in Alzheimer disease (AD) because of potential behavioral effects and its potential impact on mechanisms implicated in AD such as oxidative stress (OS) and neuroinflammation. We explored whether serum markers of OS and neuroinflammation were associated with response to the cannabinoid nabilone in agitated patients with AD (N = 38). All participants were enrolled in a 14-week, double-blind, cross-over trial comparing nabilone to placebo (6 weeks each) with a 1-week washout between phases. Samples were collected at the start and end of each phase. The cross-sectional relationship agitation (Cohen Mansfield Agitation Inventory) and OS and inflammatory markers were investigated to select markers of interest. Significant markers were then explored for their relationship with response. The OS marker, 4-hydroxynonenal (4-HNE; F_{1, 35} = 6.41, P = .016), and the proinflammatory cytokine, tumor necrosis factor-α (TNF-α; F_{1, 29} = 3.97, P = .06), were associated with agitation severity, and TNF-α remained significantly associated (F_{2, 25} = 3.69, P = .04) after adjustment for cognition. In the placebo phase, lower baseline 4-HNE was associated with decreases in agitation severity only (b = 0.01, P = .01), while lower baseline TNF-α was associated with decreases in agitation severity in the nabilone phase only (b = 1.14, P = .045). Changes in 4-HNE were not associated with changes in agitation severity in either phase. In the nabilone phase, lower baseline TNF-α was associated with decreases in agitation severity (b = 1.14, P = .045), and decreases in TNF-α were associated with decreases in agitation severity (b = 1.12, P = .006). These findings suggest that OS and neuroinflammation may be associated with agitation severity, while nabilone may have anti-inflammatory effects.

DNA repair deficiency and senescence in concussed professional athletes involved in contact sports

Mild traumatic brain injury (mTBI) leads to diverse symptoms including mood disorders, cognitive decline, and behavioral changes. In some individuals, these symptoms become chronic and persist in the long-term and can confer an increased risk of neurodegenerative disease and dementia diagnosis later in life. Despite the severity of its consequences, the pathophysiological mechanism of mTBI remains unknown. In this post-mortem case series, we assessed DNA damage-induced cellular senescence pathways in 38 professional athletes with a history of repeated mTBI and ten controls with no mTBI history. We assessed clinical presentation, neuropathological changes, load of DNA damage, morphological markers of cellular senescence, and expression of genes involved in DNA damage signaling, DNA repair, and cellular senescence including the senescence-associated secretory phenotype (SASP). Twenty-eight brains with past history of repeated mTBI history had DNA damage within ependymal cells, astrocytes, and oligodendrocytes. DNA damage burden was increased in brains with proteinopathy compared to those without. Cases also showed hallmark features of cellular senescence in glial cells including astrocytic swelling, beading of glial cell processes, loss of H3K27Me3 (trimethylation at lysine 27 of histone H3) and lamin B1 expression, and increased expression of cellular senescence and SASP pathways. Neurons showed a spectrum of changes including loss of emerin nuclear membrane expression, loss of Brahma-related gene-1 (BRG1 or SMARCA4) expression, loss of myelin basic protein (MBP) axonal expression, and translocation of intranuclear tau to the cytoplasm. Expression of DNA repair proteins was decreased in mTBI brains. mTBI brains showed substantial evidence of DNA damage and cellular senescence. Decreased expression of DNA repair genes suggests inefficient DNA repair pathways in this cohort, conferring susceptibly to cellular senescence and subsequent brain dysfunction after mTBI. We therefore suggest that brains of contact-sports athletes are characterized by deficient DNA repair and DNA damage-induced cellular senescence and propose that this may affect neurons and be the driver of brain dysfunction in mTBI, predisposing the progression to neurodegenerative diseases. This study provides novel targets for diagnostic and prognostic biomarkers, and represents viable targets for future treatments.

Markers of central inflammation in major depressive disorder: A systematic review and meta-analysis of studies examining cerebrospinal fluid, positron emission tomography and post-mortem brain tissue

BACKGROUND

Increased peripheral inflammation has been consistently reported in patients with major depressive disorder (MDD). However, only few studies have explored markers of central (brain) inflammation in patients with MDD. The aim of this study is to systematically review in vivo and post-mortem markers of central inflammation, including studies examining cerebrospinal fluid (CSF), positron emission tomography, and post-mortem brain tissues in subjects suffering with MDD compared with controls.

METHODS

PubMed and Medline databases were searched up to December 2018. We included studies measuring cerebrospinal fluid (CSF) cytokines and chemokines, positron emission tomography (PET) studies; and post-mortem studies measuring cytokines, chemokines and cell-specific markers of microglia and astrocytes, all in MDD. A meta-analysis was performed only for CSF and PET studies, as studies on post-mortem markers of inflammation had different cell-specific markers and analysed different brain regions.

RESULTS

A total of 69 studies met the inclusion criteria. CSF levels of IL-6 and TNF-α were higher in patients with MDD compared with controls (standardised mean difference SMD 0.37, 95%CI: 0.17-0.57 and SMD 0.58, 95%CI 0.26-0.90, respectively). CSF levels of IL-6 were increased in suicide attempters regardless of their psychiatric diagnosis. Translocator protein, a PET marker of central inflammation, was elevated in the anterior cingulate cortex and temporal cortex of patients with MDD compared with controls (SMD 0.78, 95%CI: 0.41-1.16 and SMD 0.52, 95%CI: 0.19-0.85 respectively). Abnormalities in CSF and PET inflammatory markers were not correlated with those in peripheral blood. In post-mortem studies, two studies found increased markers of microglia in MDD brains, while four studies found no MDD related changes. Of the studies investigating expression of cell-specific marker for astrocytes, thirteen studies reported a decreased expression of astrocytes specific markers, two studies reported increased expression of astrocytes specific markers, and eleven studies did not detect any difference. Four out of six studies reported decreased markers of oligodendrocytes in the prefrontal cortex. Post-mortem brain levels of tumor necrosis alpha (TNF-α) were also found increased in MDD.

CONCLUSIONS

Our review suggests the presence of an increase in IL-6 and TNF-alpha levels in CSF and brain parenchyma, in the context of a possible increased microglia activity and reduction of astrocytes and oligodendrocytes markers in MDD. The reduced number of astrocytes may lead to compromised integrity of blood brain barrier with increased monocyte recruitment and infiltration, which is partly supported by post-mortem studies and by PET studies showing an increased TSPO expression in MDD.

Cerebrospinal fluid markers of inflammation and infections in schizophrenia and affective disorders: a systematic review and meta-analysis

Infections and inflammatory processes have been associated with the development of schizophrenia and affective disorders; however, no study has yet systematically reviewed all available studies on cerebrospinal fluid (CSF) immune alterations. We aimed to systematically review the CSF immunological findings in schizophrenia spectrum and affective disorders. We identified all studies investigating CSF inflammatory markers in persons with schizophrenia or affective disorders published prior to March 23, 2017 searching PubMed, CENTRAL, EMBASE, Psychinfo, and LILACS. Literature search, data extraction and bias assessment were performed by two independent reviewers. Meta-analyses with standardized mean difference (SMD) including 95% confidence intervals (CI) were performed on case-healthy control studies. We identified 112 CSF studies published between 1942-2016, and 32 case-healthy control studies could be included in meta-analyses. Studies varied regarding gender distribution, age, disease duration, treatment, investigated biomarkers, and whether recruitment happened consecutively or based on clinical indication. The CSF/serum albumin ratio was increased in schizophrenia (1 study [54 patients]; SMD = 0.71; 95% CI 0.33-1.09) and affective disorders (4 studies [298 patients]; SMD = 0.41; 95% CI 0.23-0.60, I2 = 0%), compared to healthy controls. Total CSF protein was elevated in both schizophrenia (3 studies [97 patients]; SMD = 0.41; 95% CI 0.15-0.67, I2 = 0%) and affective disorders (2 studies [53 patients]; SMD = 0.80; 95% CI 0.39-1.21, I2 = 0%). The IgG ratio was increased in schizophrenia (1 study [54 patients]; SMD = 0.68; 95% CI 0.30-1.06), whereas the IgG Albumin ratio was decreased (1 study [32 patients]; SMD = -0.62; 95% CI -1.13 to -0.12). Interleukin-6 (IL-6) levels (7 studies [230 patients]; SMD = 0.55; 95% CI 0.35-0.76; I2 = 1%) and IL-8 levels (3 studies [95 patients]; SMD = 0.46; 95% CI 0.17-0.75, I2 = 0%) were increased in schizophrenia but not significantly increased in affective disorders. Most of the remaining inflammatory markers were not significantly different compared to healthy controls in the meta-analyses. However, in the studies which did not include healthy controls, CSF abnormalities were more common, and two studies found CSF dependent re-diagnosis in 3.2-6%. Current findings suggest that schizophrenia and affective disorders may have CSF abnormalities including signs of blood-brain barrier impairment and inflammation. However, the available evidence does not allow any firm conclusion since all studies showed at least some degree of bias and vastly lacked inclusion of confounding factors. Moreover, only few studies investigated the same parameters with healthy controls and high-quality longitudinal CSF studies are lacking, including impact of psychotropic medications, lifestyle factors and potential benefits of anti-inflammatory treatment in subgroups with CSF inflammation.

The chemokine CXCL1 and its receptor CXCR2 contribute to chronic stress-induced depression in mice

Depression is increasingly recognized as an inflammatory disease, with inflammatory crosstalk in the brain contributing its pathogenesis. Life stresses may up-regulate inflammatory processes and promote depression. Although cytokines are central to stress-related immune responses, their contribution to stress-induced depression remains unclear. Here, we used unpredictable chronic mild stress (UCMS) to induce depression-like behaviors in mice, as assessed through a suite of behavioral tests. C-X-C motif chemokine ligand 1 (CXCL1)-related molecular networks responsible for depression-like behaviors were assessed through intrahippocampal microinjection of lenti-CXCL1, the antidepressant fluoxetine, the C-X-C motif chemokine receptor 2 (CXCR2) inhibitor SB265610, and the glycogen synthase kinase-3β (GSK3β) inhibitor AR-A014418. Modulation of apoptosis-related pathways and neuronal plasticity were assessed via quantification of cleaved caspase-3, B-cell lymphoma 2-associated X protein, cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF) protein expression. CXCL1/CXCL2 expression was correlated with depression-like behaviors in response to chronic stress or antidepressant treatment in the UCMS depression model. Intrahippocampal microinjection of lenti-CXCL1 increased depression-like behaviors, activated GSK3β, increased apoptosis pathways, suppressed CREB activation, and decreased BDNF. Administration of the selective GSK3β inhibitor AR-A014418 abolished the effects of lenti-CXCL1, and the CXCR2 inhibitor SB265610 prevented chronic stress-induced depression-like behaviors, inhibited GSK3β activity, blocked apoptosis pathways, and restored BDNF expression. The CXCL1/CXCR2 axis appears to play a critical role in stress-induced depression, and CXCR2 is a potential novel therapeutic target for patients with depression.-Chai, H.-H., Fu, X.-C., Ma, L., Sun, H.-T., Chen, G.-Z., Song, M.-Y., Chen, W.-X., Chen, Y.-S., Tan, M.-X., Guo, Y.-W., Li, S.-P. The chemokine CXCL1 and its receptor CXCR2 contribute to chronic stress-induced depression in mice.

Plasma and cerebrospinal fluid inflammatory cytokines in perinatal depression

BACKGROUND

While perinatal depression is one of the most common complications of pregnancy, there is an insufficient understanding of the mechanistic underpinnings of disease. While an association between peripheral inflammatory cytokines and major depressive disorder has been demonstrated, cytokines cannot freely cross the blood-brain barrier, and thus, they give little insight into alternations in brain function. Because the brain is in direct communication with the cerebrospinal fluid, assessment of inflammation in the cerebrospinal fluid may be more directly related to the biologic markers of affective change.

OBJECTIVE

Our objectives were to examine the association between perinatal depression and inflammatory cytokines in plasma, the association between perinatal depression and inflammatory cytokines in cerebrospinal fluid, and the correlations between plasma and cerebrospinal fluid inflammatory cytokines.

STUDY DESIGN

This was a prospective, observational study of women with a singleton gestation at term undergoing a scheduled cesarean delivery. Women were screened for depression and those with depressive symptomatology preferentially enrolled. The Mini-International Neuropsychiatric Interview was administered to confirm the clinical diagnosis of depression. Maternal plasma and cerebrospinal fluid were collected preoperatively and cytokines measured via flow cytometry. Bivariable and multivariable analyses were used to determine the association between each cytokine and perinatal depression. Correlations were measured between the cytokines in plasma and cerebrospinal fluid.

RESULTS

Of the 117 women who met inclusion criteria, 76 (65%) screened positive for depression, 15 (20%) of whom met the clinical diagnostic criteria for depression. There were no significant associations between any of the plasma cytokines and perinatal depression in our sample. Conversely, in multivariable analyses, higher cerebrospinal fluid interleukin-1β (adjusted odds ratio, 232.7, 95% confidence interval, 5.9-9148.5), interleukin-23 (adjusted odds ratio, 22.1, 95% confidence interval, 1.7-294.5), and interleukin-33 (adjusted odds ratio, 1.7, 95% confidence interval, 1.1-2.6) concentrations were significantly associated with increased odds of perinatal depression. The plasma and cerebrospinal fluid cytokine concentrations were not strongly correlated.

CONCLUSION

Higher concentrations of cerebrospinal fluid cytokines were associated with perinatal depression. These cerebrospinal fluid cytokines were not strongly correlated with plasma cytokines, and accordingly, plasma cytokines were not significantly associated with perinatal depression. Central neuroinflammation, as opposed to peripheral inflammation, may represent a mechanistic pathway that contributes to perinatal depression.

Neuroinflammation and Cytokines in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Critical Review of Research Methods

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is the label given to a syndrome that can include long-term flu-like symptoms, profound fatigue, trouble concentrating, and autonomic problems, all of which worsen after exertion. It is unclear how many individuals with this diagnosis are suffering from the same condition or have the same underlying pathophysiology, and the discovery of biomarkers would be clarifying. The name "myalgic encephalomyelitis" essentially means "muscle pain related to central nervous system inflammation" and many efforts to find diagnostic biomarkers have focused on one or more aspects of neuroinflammation, from periphery to brain. As the field uncovers the relationship between the symptoms of this condition and neuroinflammation, attention must be paid to the biological mechanisms of neuroinflammation and issues with its potential measurement. The current review focuses on three methods used to study putative neuroinflammation in ME/CFS: (1) positron emission tomography (PET) neuroimaging using translocator protein (TSPO) binding radioligand (2) magnetic resonance spectroscopy (MRS) neuroimaging and (3) assays of cytokines circulating in blood and cerebrospinal fluid. PET scanning using TSPO-binding radioligand is a promising option for studies of neuroinflammation. However, methodological difficulties that exist both in this particular technique and across the ME/CFS neuroimaging literature must be addressed for any results to be interpretable. We argue that the vast majority of ME/CFS neuroimaging has failed to use optimal techniques for studying brainstem, despite its probable centrality to any neuroinflammatory causes or autonomic effects. MRS is discussed as a less informative but more widely available, less invasive, and less expensive option for imaging neuroinflammation, and existing studies using MRS neuroimaging are reviewed. Studies seeking to find a peripheral circulating cytokine "profile" for ME/CFS are reviewed, with attention paid to the biological and methodological reasons for lack of replication among these studies. We argue that both the biological mechanisms of cytokines and the innumerable sources of potential variance in their measurement make it unlikely that a consistent and replicable diagnostic cytokine profile will ever be discovered.

Metabonomics reveals peripheral and central short-chain fatty acid and amino acid dysfunction in a naturally occurring depressive model of macaques

PURPOSE

Depression is a complex psychiatric disorder. Various depressive rodent models are usually constructed based on different pathogenesis hypotheses.

MATERIALS AND METHODS

Herein, using our previously established naturally occurring depressive (NOD) model in a non-human primate (cynomolgus monkey, Macaca fascularis), we performed metabolomics analysis of cerebrospinal fluid (CSF) from NOD female macaques (N=10) and age-and gender-matched healthy controls (HCs) (N=12). Multivariate statistical analysis was used to identify the differentially expressed metabolites between the two groups. Ingenuity Pathways Analysis and MetaboAnalyst were applied for predicted pathways and biological functions analysis.

RESULTS

Totally, 37 metabolites responsible for discriminating the two groups were identified. The NOD macaques were mainly characterized by perturbations of fatty acid biosynthesis, ABC transport system, and amino acid metabolism (eg, aspartate, glycine, serine, and threonine metabolism). Interestingly, we found that eight altered CSF metabolites belonging to short-chain fatty acids and amino acids were also observed in the serum of NOD macaques (N=13 per group).

CONCLUSION

Our findings suggest that peripheral and central short-chain fatty acids and amino acids are implicated in the onset of depression.

Functional Bowel Disorders Are Associated with a Central Immune Activation

Background

Subjects with depression and unexplained neurological symptoms have a high prevalence of gastrointestinal comorbidity probably related to the brain-gut communication. This study explored associations between functional gastrointestinal disorders (FGID) and inflammatory markers in subjects with these disorders.

Methods

The FGID, including irritable bowel syndrome (IBS), were classified according to the Rome III criteria, and degree of symptoms was assessed with IBS symptom severity score (IBS-SSS). A range of interleukins (IL), chemokines and growth factors, tryptophan, and kynurenine were analysed in serum and the cerebrospinal fluid (CSF), and short-chain fatty acids (SCFA) were analysed in the faeces. The results are reported as partial correlation (pc) and p values.

Results

Sixty-six subjects were included. IBS was associated with high levels of tryptophan (p = 0.048) and kynurenine (p = 0.019) and low level of IL-10 (p = 0.047) in the CSF. IBS-SSS was associated with high tumor necrosis factor and low IL-10 in the CSF; pc = 0.341 and p = 0.009 and pc = −0.299 and p = 0.023, respectively. Propionic minus butyric acid in faeces was negatively associated with IL-10 in the CSF (pc = −0.416, p = 0.005).

Conclusions

FGID were associated with a proinflammatory immune activation in the central nervous system and a disturbed tryptophan metabolism that could have been mediated by the faecal microbiota.

The Relationships among Tryptophan, Kynurenine, Indoleamine 2,3-Dioxygenase, Depression, and Neuropsychological Performance

It has been suggested that the metabolic enzyme indoleamine 2,3-dioxygenase (IDO) is a biological mediator of inflammation related to the psychopathology of depression, with a Kynurenine (KYN) increase in the Tryptophan (TRP) metabolic pathway, resulting in reduced Serotonin. In this study, we examined KYN, TRP, and the ratio of KYN to TRP concentrations × 10³ (KT Ratio) in serum and cerebrospinal fluid (CSF) in (a) a group of depressed patients and (b) a control group of patients referred to a neurologic outpatient clinic for whom no specific diagnosis could be established. The KT Ratio is considered an index that represents IDO. The participants were examined with the Beck Depression Inventory II (BDI-II), the Montgomery Aasberg Depression Rating Scale (MADRS), and a neuropsychological test battery. We found no significant differences between the two study groups with respect to TRP, KYN, or KT Ratio in serum or CSF. Differences in neuropsychological performance between the two patient groups could be seen in the following tests: Animal Fluency, Digit Symbol, the DKEFS Color-Interference Test (Naming Part), Trail Making Test A and B, and the Grooved Pegboard Non-dominant Hand. KYN in serum correlated highly with KYN in CSF. KYN in serum correlated significantly with both age and gender. When analyzing males and females separately, we found that women had a lower level of TRP in both serum (Mann-Whitney U-test: TRP in Serum; p = 0.001) and CSF (Mann-Whitney U-test: TRP in CSF; p = 0.003). Women had a lower level of KYN in serum (p = 0.029) than men did. Age was positively associated with KYN. KYN in CSF correlated only with age, however; there were no gender differences. No significant relationship was seen between BDI-II and MADRS on the one hand, and KYN and TRP on the other. KYN in CSF as the KT Ratio in both serum and CSF was associated with neuropsychological performance. Thus, we suggest that KYN and KT Ratio are related more strongly to neuropsychological performance than to affective symptoms in depression.

Translational Identification of Transcriptional Signatures of Major Depression and Antidepressant Response

Major depressive disorder (MDD) is a highly prevalent mental illness whose therapy management remains uncertain, with more than 20% of patients who do not achieve response to antidepressants. Therefore, identification of reliable biomarkers to predict response to treatment will greatly improve MDD patient medical care. Due to the inaccessibility and lack of brain tissues from living MDD patients to study depression, researches using animal models have been useful in improving sensitivity and specificity of identifying biomarkers. In the current study, we used the unpredictable chronic mild stress (UCMS) model and correlated stress-induced depressive-like behavior (n = 8 unstressed vs. 8 stressed mice) as well as the fluoxetine-induced recovery (n = 8 stressed and fluoxetine-treated mice vs. 8 unstressed and fluoxetine-treated mice) with transcriptional signatures obtained by genome-wide microarray profiling from whole blood, dentate gyrus (DG), and the anterior cingulate cortex (ACC). Hierarchical clustering and rank-rank hypergeometric overlap (RRHO) procedures allowed us to identify gene transcripts with variations that correlate with behavioral profiles. As a translational validation, some of those transcripts were assayed by RT-qPCR with blood samples from 10 severe major depressive episode (MDE) patients and 10 healthy controls over the course of 30 weeks and four visits. Repeated-measures ANOVAs revealed candidate trait biomarkers (ARHGEF1, CMAS, IGHMBP2, PABPN1 and TBC1D10C), whereas univariate linear regression analyses uncovered candidates state biomarkers (CENPO, FUS and NUBP1), as well as prediction biomarkers predictive of antidepressant response (CENPO, NUBP1). These data suggest that such a translational approach may offer new leads for clinically valid panels of biomarkers for MDD.