Interleukin-6 and Interleukin-10 in mood disorders: A population-based study

Recurrent COVID-19-related psychotic disorder with neuro-immuno-endocrine dysfunction as a possible underlying mechanism: A case report from China

Background

SARS-CoV-2, first identified in Wuhan, China, in December 2019, has been gradually spreading worldwide since 2020. The relationship between SARS-CoV-2 infection and psychotic disorders has received much attention, and several studies have described the direct/indirect mechanisms of its effects on the brain, but no mechanism has been found to explain recurrent episodes of COVID-19-related psychotic symptoms.

Case

We report the case of an 18-year-old female patient with no family or personal psychotic disorder history with multiple hospital admissions with symptoms such as disorganized speech and behavior, hyperactivity, restlessness, and impulsive aggression during the COVID-19 recovery period. Relevant tests revealed longitudinal changes such as persistent IL-6 and IL-10 elevation, abnormal discharges on EEG, and brain and hippocampal MRI abnormal signals. The patient was treated with antipsychotics, MECT, combination therapy of hormones and antivirals, then discharged after multiple treatment rounds.

Conclusion

The case presented here outlines the possibility that the COVID-19 recovery period may be a critical period for acute psychotic episodes and that the patient's recurrent psychotic symptoms may be associated with neuro-immuno-endocrine dysfunction mediated by sustained cytokine synthesis, further causing structural and functional brain damage. Routine psychiatric evaluation and related screening should be performed at all stages of the illness to better identify, prevent, and effectively intervene in psychiatric disorders following COVID-19. Because many outcomes require long-term assessment, a clearer understanding of the impact of the COVID-19 epidemic on mental health is likely to emerge in the future.

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.

Mitigation and mechanism of low dose linoleic acid on depression caused by disorder of gut microbiome

OBJECTIVES

Depression is a widely prevalent mental disorder, and nutritional interventions play an increasingly important role in its treatment. In this paper, effects of linoleic acid (LA) on depressive behavior in mice induced by gut microbiome disorders were investigated.

METHODS

Fifty C57BL/6J male mice were randomly separated into five groups, control group (CK), ceftriaxone sodium group (CRO), low-dose linoleic acid group (LLA, 1 g/kg), medium-dose linoleic acid group (MLA, 2 g/kg), and high-dose linoleic acid group (HLA, 5 g/kg). In the LLA, MLA, and HLA groups, mice were treated with ceftriaxone sodium (CRO) to induce depressive behaviors, followed by LA administration. Behavioral tests were used to evaluate depressive behavior. High-throughput sequencing and Hematoxylin-eosin (H&E) staining in gut microenvironment were carried out. ELISA kits were used to measure brain inflammatory factors, and 5-hydroxy-tryptamine (5-HT). Gas chromatography and western blot were used to determine fatty acids compositions and the enzymes expression involved in lipid metabolism in brain respectively.

RESULTS

The results showed that 10 weeks CRO treatment contribute to depressive behavior, gut microbiome disturbance, and serotonin system disturbance. LLA and MLA improved the depressive-like behavior, and significantly increased the levels of 5-HT1A, 5-HTT and 5-HT in the hippocampus. LLA was found to improve the diversity of gut microbiome and alleviate colon tissue damage. Meantime, LLA increased the content of linoleic acid, improved the expression of FADS2 and COX-2, increased IL-10 levels, and decreased IL-6 levels in the brain.

DISCUSSION

LA alleviated depressive behavior in mice by improving the gut microenvironment, regulate fatty acid metabolism, and modulate inflammation.

C-reactive protein concentrations diverge as a function of substance use disorder: A pre-registered replication in a clinical sample

BACKGROUND

Inflammatory biomarkers may differentiate clinical disorders, which could lead to more targeted interventions. Analyses within a clinical sample (May et al., 2021) revealed that females with substance use disorders (SUD) exhibited lower C-reactive protein (CRP) and higher interleukin (IL)-8 and -10 concentrations than females without SUD who met criteria for mood/anxiety disorders. We aimed to replicate these findings in a new sample.

METHODS

Hypotheses and analyses were preregistered. Treatment-seeking individuals with mood/anxiety disorders and/or SUD (N = 184) completed a blood draw, clinical interview, and questionnaires. Participants were categorized as SUD+ (45F, 43M) and SUD- (78F, 18M). Principal component analysis (PCA) of questionnaire data resulted in two factors reflecting appetitive and aversive emotional states. SUD group and nuisance covariates (PCA factors, age, body mass index [BMI], medication, nicotine [and hormones in females]) predicted biomarker concentrations (CRP, IL-8, and IL-10) in regressions.

RESULTS

In females, the omnibus CRP model [F(8, 114) = 8.02, p <.001, R²-adjusted =.32] indicated that SUD+ exhibited lower CRP concentrations than SUD- (β = -.33, t = -3.09, p =.002, 95% CI [-.54, -.12]) and greater BMI was associated with higher CRP levels (β =.58, t = 7.17, p <.001, 95% CI [.42,.74]). SUD+ exhibited higher IL-8 levels than SUD- in simple but not omnibus regression models.

CONCLUSION

Findings across two samples bolster confidence that females with SUD show attenuated CRP-indexed inflammation. As SUD+ comorbidity was high, replication is warranted with respect to specific SUD classes (i.e., stimulants versus cannabis).

Altered serum cytokines in patients with symptomatic disk herniation and depressive symptoms

Purpose

An increasing number of studies have indicated the important role of cytokines in the development of depressive disturbances (DD). In medically ill patients, cytokines can provoked sickness behavior, the signs of which resemble DD. This results in alterations in behavior to limit energy expenditure and redirect it to cope with particular diseases. The aim of our study was to investigate the role of pro-inflammatory IL-6, TNF-α, and IL-1β and anti-inflammatory IL-10 and TGF-β in DD observed in patients suffering from pain caused by disk herniation (DH) qualified for surgery.

Patients and methods

The intensity of DD assessed by using Beck Depression Inventory, pain intensity, and functional impairment were evaluated in 70 patients with DH who were qualified for surgery. Pro-inflammatory serum levels of TNF-α, IL-1, IL-6, anti-inflammatory TGF-β, and IL-10 were measured.

Results

Elevated serum levels of TGF-β, IL-10, and IL-6 were found in the group with moderate and severe depressive symptoms (SD) compared with the groups with mild (MD) or no depressive symptoms (ND). TGF-β levels were negatively correlated with pain intensity, as assessed using the Present Pain Intensity scale in SD. Functional impairment measured using the Oswestry Disability Index was the most advanced in SD group.

Conclusion

Results of our study can suggest association between depressive disturbances and anti-inflammatory cytokines TGF-β and IL-10. Functional impairment of SD group is more severe but serum levels of TGF-β and IL-10, which are involved in the healing processes, are increased.

Neuroinflammation and Post-Stroke Depression: Focus on the Microglia and Astrocytes

Post-stroke depression (PSD), a frequent and disabling complication of stroke, has a strong impact on almost thirty percent of stroke survivors. The pathogenesis of PSD is not completely clear so far. Neuroinflammation following stroke is one of underlying mechanisms that involves in the pathophysiology of PSD and plays an important function in the development of depression and is regarded as a sign of depression. During the neuroinflammation after ischemic stroke onset, both astrocytes and microglia undergo a series of morphological and functional changes and play pro-inflammatory or anti-inflammatory effect in the pathological process of stroke. Importantly, astrocytes and microglia exert dual roles in the pathological process of PSD due to the phenotypic transformation. We summarize the latest evidence of neuroinflammation involving in PSD in this review, focus on the phenotypic transformation of microglia and astrocytes following ischemic stroke and reveal the dual roles of both microglia and astrocytes in the PSD via modulating the neuroinflammation.

Upregulation of proBDNF/p75NTR signaling in immune cells and its correlation with inflammatory markers in patients with major depression

ProBDNF is the precursor protein of brain-derived neurotrophic factor (BDNF) expressed in the central nervous system and peripheral tissues. Previous studies showed that the blood levels of both proBDNF and p75 neurotrophic receptors (p75NTR) in major depressive disorder (MDD) were increased, but which blood cell types express proBDNF and its receptors is not known. Furthermore, the relationship between proBDNF/p75NTR and inflammatory cytokines in peripheral blood of MDD is unclear. Peripheral blood mononuclear cells (PBMCs) and serum were obtained from depressive patients (n = 32) and normal donors (n = 20). We examined the expression of proBDNF and inflammatory markers and their correlative relationship in patients with major depression. Using flow cytometry analysis, we examined which blood cells express proBDNF and its receptors. Finally, the role of proBDNF/p75NTR signal in inflammatory immune activity of PBMCs was verified in vitro experiments. Inflammatory cytokines in PBMC from MDD patients were increased and correlated with the major depression scores. The levels of IL-1β and IL-10 were also positively correlated with the major depression scores, while the levels of TNF-α and IL-6 were negatively correlated with the major depression scores. Intriguingly, the levels of sortilin were positively correlated with IL-1β. Q-PCR and Western blots showed proBDNF, p75NTR, and sortilin levels were significantly increased in PBMCs from MDD patients compared with that from the normal donors. Flow cytometry studies showed that proBDNF and p75NTR were present mainly in CD4+ and CD8+ T cells. The number of proBDNF and p75NTR positive CD4+ and CD8+ T cells from MDD patients was increased and subsequently reversed after therapeutic management. Exogenous proBDNF protein or p75ECD-Fc treatment of cultured PBMC affected the release of inflammatory cytokines in vitro. ProBDNF promoted the expression of inflammatory cytokines, while p75ECD-Fc inhibited the expression of inflammatory cytokines. Given there was an inflammatory response of lymphocytes to proBDNF, it is suggested that proBDNF/p75NTR signaling may upstream inflammatory cytokines in MDD. Our data suggest that proBDNF/p75NTR signaling may not only serve as biomarkers but also may be a potential therapeutic target for MDD.

Investigating the Potential Mechanisms and Therapeutic Targets of Inflammatory Cytokines in Post-stroke Depression

Post-stroke depression (PSD) affects approximately one-third of stroke survivors, severely impacting general recovery and quality of life. Despite extensive studies, the exact mechanisms underlying PSD remain elusive. However, emerging evidence implicates proinflammatory cytokines, including interleukin-1β, interleukin-6, tumor necrosis factor-alpha, and interleukin-18, play critical roles in PSD development. These cytokines contribute to PSD through various mechanisms, including hypothalamic-pituitary-adrenal (HPA) axis dysfunction, neurotransmitter alterations, neurotrophic factor changes, gut microbiota imbalances, and genetic predispositions. This review is aimed at exploring the role of cytokines in stroke and PSD while identifying their potential as specific therapeutic targets for managing PSD. A more profound understanding of the mechanisms regulating inflammatory cytokine expression and anti-inflammatory cytokines like interleukin-10 in PSD may facilitate the development of innovative interventions to improve outcomes for stroke survivors experiencing depression.

Levels of IL-6 are Associated with Lifetime Attempted Suicide in Alcohol Use Disorder Patients

Background

Patients with alcohol use disorder (AUD) have an increased risk of suicide. Neuroimmunological measures, such as cytokines, are shown to deviate in people with attempted suicide. Few studies have investigated this among AUD patients.

Patients and Methods

One-hundred and fourteen patients undergoing residential treatment for AUD were interviewed on lifetime suicide attempts (SA) along with several other background variables and clinical characteristics. Serum blood samples were drawn for analysis of cytokines.

Results

Thirty-one patients (27%) reported at least one SA. These patients had more symptoms of current affective disorders and more severe dependence. In bivariate analysis only IL-6 and IL-10 appeared to be associated with lifetime SA but without reaching statistical significance. In multivariate linear regression, adjusting for sex, nicotine use, somatic illness, and the use of anti-inflammatory drugs, IL-6 was associated to SA (p = 0.033).

Conclusion

The cytokine IL-6 has repeatedly been found to be associated with suicidality. The present study concurs with this role of IL-6 in a naturalistic observational study of AUD patients.

Depression, anxiety, insomnia and interleukins in the early postpartum period

Background

Some new mothers have been shown to suffer from anxiety and depression associated with insomnia during the postpartum period. Our study assessed the impact of demographic, psychopathological, and biochemical factors on the incidence of depression in women during the early postpartum period.

Methods

A total of 119 women were evaluated at 24-48 h postpartum with the following psychometric scales: Hamilton Depression Rating Scale (HDRS), Edinburgh Postnatal Depression Scale (EPDS), Hamilton Anxiety Rating Scale (HARS) and Athens Insomnia Scale (AIS). In addition, blood was drawn to assay interleukin 6 (IL-6) and interleukin 10 (IL-10).

Results

The factors that had the greatest impact on the risk of postpartum depression detected with the HDRS were high HARS scores and evidence of insomnia in the AIS. There were no significant differences in IL-6 or IL-10 levels in women with and without depression (based on either HDRS or EPDS scores) and insomnia (based on AIS) after childbirth. Considering demographic factors, divorced and single women were shown to be at higher risk of postpartum depression (based on EPDS scores).

Limitations

Small sample size and short observation span.

Conclusion

This study highlights the relationship between postpartum depression and both anxiety and insomnia and emphasises the importance to assess symptoms of anxiety and sleep quality as part of screening in women at risk of postpartum depression.

Potential Inflammatory Biomarkers for Major Depressive Disorder Related to Suicidal Behaviors: A Systematic Review

Major depressive disorder (MDD) is a highly prevalent psychiatric condition affecting an estimated 280 million individuals globally. Despite the occurrence of suicidal behaviors across various psychiatric conditions, MDD is distinctly associated with the highest risk of suicide attempts and death within this population. In this study, we focused on MDD to identify potential inflammatory biomarkers associated with suicidal risk, given the relationship between depressive states and suicidal ideation. Articles published before June 2023 were searched in PubMed, Embase, Web of Science, and the Cochrane Library to identify all relevant studies reporting blood inflammatory biomarkers in patients with MDD with suicide-related behaviors. Of 571 articles, 24 were included in this study. Overall, 43 significant biomarkers associated with MDD and suicide-related behaviors were identified. Our study provided compelling evidence of significant alterations in peripheral inflammatory factors in MDD patients with suicide-related behaviors, demonstrating the potential roles of interleukin (IL)-1β, IL-6, C-reactive protein, C-C motif chemokine ligand 2, and tumor necrosis factor-α as biomarkers. These findings underscore the intricate relationship between the inflammatory processes of these biomarkers and their interactions in MDD with suicidal risk.

How to save a life: From neurobiological underpinnings to psychopharmacotherapies in the prevention of suicide

The impact of suicide on our societies, mental healthcare, and public health is beyond questionable. Every year approximately 700 000 lives are lost due to suicide around the world (WHO, 2021); more people die by suicide than by homicide and war. Although suicide is a key issue and reducing suicide mortality is a global imperative, suicide is a highly complex biopsychosocial phenomenon, and in spite of several suicidal models developed in recent years and a high number of suicide risk factors identified, we still have neither a sufficient understanding of underpinnings of suicide nor adequate management strategies to reduce its prevalence. The present paper first overviews the background of suicidal behavior including its epidemiology, prevalence, age and gender correlations and its association with neuropsychiatric disorders as well as its clinical assessment. Then we give an overview of the etiological background, including its biopsychosocial contexts, genetics and neurobiology. Based on the above, we then provide a critical overview of the currently available intervention options to manage and reduce risk of suicide, including psychotherapeutic modalities, traditional medication classes also providing an up-to-date overview on the antisuicidal effects of lithium, as well as novel molecules such as esketamine and emerging medications and further molecules in development. Finally we give a critical overview on our current knowledge on using neuromodulatory and biological therapies, such as ECT, rTMS, tDCS and other options.

Childhood trauma, inflammatory biomarkers and the presence of a current depressive episode: Is there a relationship in subjects from a population study?

This study aims to compare the serum cytokine levels between controls, individuals with a current depressive episode (CDE) with childhood trauma and individuals with CDE without childhood trauma. This is a cross-sectional with paired sample nested in a population-based study. For the purposes of the current study, subjects who had psychotic symptoms, generalized anxiety disorder, and who refused to perform blood collection were excluded. Subsequently, only individuals who had a current depressive episode were selected (n = 76). Another 76 subjects were randomly paired by sex and age, constituting a population control group. The measurements of serum cytokine levels were performed using the multiplex analysis method. In the group with a CDE, when compared to the population control group, the following cytokines were high: IL-1β, IL-2, IL-4, IL-6, IL-17A, IFN-γ and TNF-α (p < 0.05). On the other hand, there was a decrease in the levels of cytokines IL-10 (p = 0.027) and IL12p70 (p = 0.001). Bonferroni test demonstrates that there is no statistically significant difference in serum cytokine levels between subjects with a CDE, with and without trauma (p > 0.05). In a multivariable logistic regression, adjusting for socioeconomic status, tobacco, alcohol and illicit drugs abuse/dependence, and use of psychiatric medication, we found that cytokines serum levels remained associated with CDE even when adjusted for these potential confounders. Our findings demonstrate that monitoring cytokine levels and immune function may be beneficial in preventing the development of a CDE. However, future research is necessary to investigate the impact of trauma on the relationship between inflammation and CDE.

Relationships of Low Serum Levels of Interleukin-10 With Poststroke Anxiety and Cognitive Impairment in Patients With Clinical Acute Stroke

BACKGROUND AND PURPOSE

The relationships among interleukin (IL)-10 levels, anxiety, and cognitive status after stroke remain controversial. We aimed to determine the associations of serum IL-10 levels with poststroke anxiety (PSA) and poststroke cognitive impairment (PSCI).

METHODS

We recruited 350 patients with stroke, of whom only 151 completed a 1-month follow-up assessment. The Mini Mental State Examination (MMSE) and Hamilton Anxiety Scale (HAMA) were used to assess the cognitive status and anxiety, respectively. Serum IL-10 levels were measured within 24 hours of admission.

RESULTS

IL-10 levels were significantly lower in the PSA group than in the non-PSA group, and they were negatively associated with HAMA scores (r=-0.371, p<0.001). After adjusting for all potential confounders, IL-10 levels remained an independent predictor of PSA (odds ratio=0.471, 95% confidence interval=0.237-0.936, p=0.032). IL-10 levels were strongly correlated with behavior during interviews, psychic anxiety, and somatic anxiety. Patients without PSCI had higher IL-10 levels were higher in non-PSCI patients than in PSCI patients, and they were positively associated with MMSE scores in the bivariate correlation analysis (r=0.169, p=0.038), and also with memory capacity, naming ability, and copying capacity. However, IL-10 did not predict PSCI in the univariable or multivariable logistic regression.

CONCLUSIONS

Low IL-10 levels were associated with increased risks of PSA and PSCI at a 1-month follow-up after stroke. Serum IL-10 levels may therefore be helpful in predicting PSA.

Inflammatory bowel diseases, interleukin-6 and interleukin-6 receptor subunit alpha in causal association with cerebral cortical structure: a Mendelian randomization analysis

Background

Neurological involvement and psychiatric manifestations have been documented in clinical cases of inflammatory bowel disease (IBD); however, the presence of a causal relationship remains elusive. The objective of this study is to investigate the modifications occurring in the cerebral cortex as a result of IBD.

Methods

A compendium of data extracted from a genome-wide association study (GWAS) involving a maximum of 133,380 European subjects. A series of Mendelian random analyses were applied to exclude heterogeneity and pleiotropy, ensuring the stability of the results.

Results

Neither IBDs nor inflammatory cytokines (IL-6/IL-6Rα) were found to have a significant causality with surface area (SA) and thickness (TH) at the global level. At the regional functional brain level, Crohn's disease (CD) significantly decreased the TH of pars orbitalis (β=-0.003mm, Se=0.001mm, p_ivw =4.85×10^-4). IL-6 was observed to reduce the SA of middle temporal (β=-28.575mm², Se=6.482mm², p_ivw=1.04×10^-5) and increase the TH of fusiform (β=0.008mm, Se=0.002mm, p_ivw=8.86×10^-5) and pars opercularis (β=0.009mm, Se=0.002mm, p_ivw=2.34×10^-4). Furthermore, a causal relationship between IL-6Rα and an increase in the SA of superior frontal (β=21.132mm², Se=5.806mm², p_ivw=2.73×10^-4) and the TH of supramarginal (β=0.003mm, Se=0.0002mm, p_ivw=7.86×10^-37). All results passed sensitivity analysis and no heterogeneity and pleiotropy were detected.

Conclusion

The correlation between IBD and changes in cerebral cortical structures implies the existence of a gut-brain axis at the organismal level. It is recommended that clinical patients with IBD prioritize long-term management of inflammation, as changes at the organismal level can lead to functional pathologies. Magnetic resonance imaging (MRI) may be considered as an additional screening option for IBD.

Selected Biomarkers of Depression: What Are the Effects of Cytokines and Inflammation?

Depression is one of the leading mental illnesses worldwide and lowers the quality of life of many. According to WHO, about 5% of the worldwide population suffers from depression. Newer studies report a staggering global prevalence of 27.6%, and it is rising. Professionally, depression belonging to affective disorders is a psychiatric illness, and the category of major depressive disorder (MDD) comprises various diagnoses related to persistent and disruptive mood disorders. Due to this fact, it is imperative to find a way to assess depression quantitatively using a specific biomarker or a panel of biomarkers that would be able to reflect the patients' state and the effects of therapy. Cytokines, hormones, oxidative stress markers, and neuropeptides are studied in association with depression. The latest research into inflammatory cytokines shows that their relationship with the etiology of depression is causative. There are stronger cytokine reactions to pathogens and stressors in depression. If combined with other predisposing factors, responses lead to prolonged inflammatory processes, prolonged dysregulation of various axes, stress, pain, mood changes, anxiety, and depression. This review focuses on the most recent data on cytokines as markers of depression concerning their roles in its pathogenesis, their possible use in diagnosis and management, their different levels in bodily fluids, and their similarities in animal studies. However, cytokines are not isolated from the pathophysiologic mechanisms of depression or other psychiatric disorders. Their effects are only a part of the whole pathway.

A pathway phenotype linking metabolic, immune, oxidative, and opioid pathways with comorbid depression, atherosclerosis, and unstable angina

BACKGROUND

There is strong comorbidity between atherosclerosis (ATS) and depression which is attributed to increased atherogenicity, insulin resistance (IR), and immune and oxidative stress.

AIM OF THE STUDY

To examine the role of the above pathways and mu-opioid receptor (MOR), β-endorphin levels, zinc, copper, vitamin D3, calcium, and magnesium in depression due to ATS/unstable angina (UA).

METHODS

Biomarkers were assayed in 58 controls and 120 ATS patients divided into those with moderate and severe depression according to the Beck Depression Inventory-II (BDI-II) scores >19 and >29, respectively.

RESULTS

Neural network and logistic regression models showed that severe depression due to ATS/UA was best predicted by interleukin-6 (IL-6), UA, MOR, zinc, β-endorphin, calcium and magnesium, and that moderate depression was associated with IL-6, zinc, MOR, β-endorphin, UA, atherogenicity, IR, and calcium. Neural networks yielded a significant discrimination of severe and moderate depression with an area under the receiver operating curves of 0.831 and 0.931, respectively. Using Partial Least Squares path analysis, we found that 66.2% of the variance in a latent vector extracted from ATS/UA clinical features, and the BDI-II scores, atherogenicity, and IR could be explained by the regression on IL-6, IL-10, zinc, copper, calcium, MOR, and age. The BDI-II scores increased from controls to ATS to UA class III to UA class IV.

CONCLUSIONS

Immune activation, the endogenous opioid system, antioxidants, trace elements, and macrominerals modulate a common core shared by increased depressive symptoms, ATS, UA, atherogenicity, and IR.

Anxiolytic and antidepressive potentials of rosmarinic acid: A review with a focus on antioxidant and anti-inflammatory effects

Depression and anxiety are the most prevalent neuropsychiatric disorders that have emerged as global health concerns. Anxiolytic and antidepressant drugs, such as benzodiazepines, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, and tricyclics, are the first line used in treating anxiety and depression. Although these drugs lack efficacy and have a delayed response time and numerous side effects, their widespread abuse and market continue to grow. Over time, traditional practices using natural and phytochemicals as alternative therapies to chemical drugs have emerged to treat many pathological conditions, including anxiety and depression. Recent preclinical studies have demonstrated that the phenolic compound, rosmarinic acid, is effective against several neuropsychiatric disorders, including anxiety and depression. In addition, rosmarinic acid showed various pharmacological effects, such as cardioprotective, hepatoprotective, lung protective, antioxidant, anti-inflammatory, and neuroprotective effects. However, the potentialities of the use of rosmarinic acid in the treatment of nervous system-related disorders, such as anxiety and depression, are less or not yet reviewed. Therefore, the purpose of this review was to present several preclinical and clinical studies, when available, from different databases investigating the effects of rosmarinic acid on anxiety and depression. These studies showed that rosmarinic acid produces advantageous effects on anxiety and depression through its powerful antioxidant and anti-inflammatory properties. This review will examine and discuss the possibility that the anxiolytic and anti-depressive effects of rosmarinic acid could be associated with its potent antioxidant and anti-inflammatory activities.

Extracellular Nucleosomes Accelerate Microglial Inflammation via C-Type Lectin Receptor 2D and Toll-Like Receptor 9 in mPFC of Mice With Chronic Stress

Damage-associated molecular patterns (DAMPs) are the primary promoter of progressive neuroinflammation and are associated with chronic stress-related emotional disorders. The present study investigated the role and mechanism of extracellular nucleosomes and histones, the newly defined DAMPs, in mice with chronic stress. C57BL/6 mice were exposed to chronic unpredictable mild stress (CUMS) and corticosterone drinking, respectively, for 4 weeks. Negative emotional behaviors were comprehensively investigated. Microglial morphology, oxidative stress, and inflammation, as well as C-type lectin receptor 2D (Clec2d) and Toll-like receptor 9 (TLR9) expression in medial prefrontal cortex (mPFC) were assessed with flow cytometer and cell sorting. Specifically, microglial pro-inflammatory activation and inflammation were further investigated with stereotactic injection of recombinant nucleosomes and histones in mPFC and further evaluated with AAV-Clec2d knocking-down, DNase I, and activated protein C (APC) pretreatment. Moreover, the rescue effect by AAV-Clec2d knocking-down was observed in mice with chronic stress. Mice with chronic stress were presented as obviously depressive- and anxiety-like behaviors and accompanied with significant microglial oxidative stress and inflammation, indicating by reactive oxygen species (ROS) production, primed nuclear factor-κB (NF-κB) signaling pathway, activated NACHT, LRR, and PYD domain–containing protein 3 (NLRP3) inflammasome, and upregulated Clec2d and TLR9 in mPFC, together with histones dictation in cerebrospinal fluid and extracellular trap formation. Stereotactic injection of nucleosomes was contributed to promote microglial inflammation rather than histones in mPFC, indicating that the pro-inflammatory role was derived from extracellular histones-bound DNA but not freely histones. AAV-Clec2d knocking-down, DNase I, and APC were all effective to inhibit nucleosome-induced microglial oxidative stress and inflammation. Moreover, AAV-Clec2d knocking-down in mice with chronic stress exhibited reduced microglial inflammation and improved negative emotional behaviors. Our findings reveal a novel mechanism of DAMP-associated inflammation that extracellular nucleosomes accelerate microglial inflammation via Clec2d and TLR9, and then contribute to chronic stress-induced emotional disorders.

Pro-inflammatory cytokines and suicidal behavior among patients with bipolar I disorder

OBJECTIVE

Suicidal behavior and different mood states of bipolar I disorder (BD) have been shown to be associated with dysregulated proinflammatory cytokines. Only a few studies have examined the association between inflammation and SB in BD, and the association between proinflammatory cytokines, SB, and cognitive deficits in patients with BD remains unclear.

METHODS

77 patients with BD and 61 age-/sex-matched healthy controls were recruited. Patients were divided into two groups: with suicidal ideation (SI; n = 21) and no SI (n = 56). SI was defined by a score of ≥1 in item 10 of Montgomery Åsberg Depression Rating Scale. Levels of proinflammatory cytokines, including soluble interleukin-6 receptor (sIL-6R), soluble tumor necrosis factor-α receptor type 1 (sTNF-αR1), and C-reactive protein (CRP), were measured, and cognitive function was assessed using 2-back task and Go/No-Go task.

RESULTS

Patients with SI had higher levels of sTNF-αR1 than those without SI and the controls (p = .004). BD patients with or without a history of suicide attempt had higher levels of CRP than the controls. SI was associated with serum levels of sTNF-αR1 and IL-6sR, even after additionally controlling for working memory and inhibitory control (p < .05).

CONCLUSION

This study indicates that serum levels of sTNF-αR1 have distinct differences between BD patients with or without SI, and our findings strengthen the hypothesis of a link between suicidal behavior and neuro-inflammation pathophysiology in BD.

Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disorder which affects the joints in the wrists, fingers, and knees. RA is often associated with depressive and anxiety symptoms as well as chronic fatigue syndrome (CFS)-like symptoms. This paper examines the association between depressive symptoms (measured with the Beck Depression Inventory, BDI), anxiety (Hamilton Anxiety Rating Scale, HAMA), CFS-like (Fibro-fatigue Scale) symptoms and immune–inflammatory, autoimmune, and endogenous opioid system (EOS) markers, and lactosylcer-amide (CD17) in RA. The serum biomarkers were assayed in 118 RA and 50 healthy controls. Results were analyzed using the new precision nomothetic psychiatry approach. We found significant correlations between the BDI, FF, and HAMA scores and severity of RA, as assessed with the DAS28-4, clinical and disease activity indices, the number of tender and swollen joints, and patient and evaluator global assessment scores. Partial least squares analysis showed that 69.7% of the variance in this common core underpinning psychopathology and RA symptoms was explained by immune–inflammatory pathways, rheumatoid factor, anti-citrullinated protein antibodies, CD17, and mu-opioid receptor levels. We constructed a new endophenotype class comprising patients with very high immune–inflammatory markers, CD17, RA, affective and CF-like symptoms, and tobacco use disorder. We extracted a reliable and replicable latent vector (pathway phenotype) from immune data, psychopathology, and RA-severity scales. Depression, anxiety, and CFS-like symptoms due to RA are manifestations of the phenome of RA and are mediated by the effects of the same immune–inflammatory, autoimmune, and other pathways that underpin the pathophysiology of RA.

A serum proteomic study of two case-control cohorts identifies novel biomarkers for bipolar disorder

We set out to identify novel protein associations with potential as clinically viable biomarkers for bipolar disorder. To this end, we used proximity extension assay to analyze 201 unique proteins in blood serum from two independent cohorts comprising patients with bipolar disorder and healthy controls (total n = 493). We identified 32 proteins significantly associated with bipolar disorder in both case-control cohorts after adjusting for relevant covariates. Twenty-two findings are novel to bipolar disorder, but 10 proteins have previously been associated with bipolar disorder: chitinase-3-like protein 1, C-C motif chemokine 3 (CCL3), CCL4, CCL20, CCL25, interleukin 10, growth/differentiation factor-15, matrilysin (MMP-7), pro-adrenomedullin, and TNF-R1. Next, we estimated the variance in serum protein concentrations explained by psychiatric drugs and found that some case-control associations may have been driven by psychiatric drugs. The highest variance explained was observed between lithium use and MMP-7, and in post-hoc analyses and found that the serum concentration of MMP-7 was positively associated with serum lithium concentration, duration of lithium therapy, and inversely associated with estimated glomerular filtration rate in an interaction with lithium. This is noteworthy given that MMP-7 has been suggested as a mediator of renal tubulointerstitial fibrosis, which is characteristic of lithium-induced nephropathy. Finally, we used machine learning to evaluate the classification performance of the studied biomarkers but the average performance in unseen data was fair to moderate (area under the receiver operating curve = 0.72). Taken together, our serum biomarker findings provide novel insight to the etiopathology of bipolar disorder, and we present a suggestive biomarker for lithium-induced nephropathy.

Depression and Inflammatory Markers in Veterans With Multiple Sclerosis

Multiple sclerosis (MS), an inflammatory neurodegenerative disease of the central nervous system (CNS), afflicts over one per thousand people in the United States. The pathology of MS typically involves lesions in several regions, including the brain and spinal cord. The manifestation of MS is variable and carries great potential to negatively impact quality of life (QOL). Evidence that inflammatory markers are related to depression in MS is accumulating. However, there are barriers in precisely identifying the biological mechanisms underlying depression and inflammation. Analysis of cytokines provides one promising approach for understanding the mechanisms that may contribute to MS symptoms.

METHODS

In this pilot study, we measured salivary levels of interleukin (IL)-6, IL-1beta (β), and IL-10 in 24 veterans with MS. Descriptive statistics were reported and Pearson correlation coefficients were obtained between cytokines and depression.

RESULTS

The anti-inflammatory cytokine IL-10 was significantly negatively associated with depression in veterans with MS (r = -0.47, p = .024).

CONCLUSION

Cytokines may be useful for elucidating biological mechanisms associated with the depression and a measure for nurses caring for veterans with MS.

Peripheral levels of C-reactive protein, tumor necrosis factor-α, interleukin-6, and interleukin-1β across the mood spectrum in bipolar disorder: A meta-analysis of mean differences and variability

IMPORTANCE

It is unclear whether differences exist in the magnitude and variability of pro-inflammatory mediators in the different phases of bipolar disorder (BD) and among subjects with BD, as compared to healthy controls.

OBJECTIVE

To run a comparative meta-analysis of C-Reactive Protein (CRP), IL-1, IL-6, TNF-α in BD vs healthy controls, measuring mean and variability effects on all subjects. Sensitivity analyses include disease activity.

DATA SOURCES

Systematic review of observational studies in PubMed and PsycInfo up to February 2nd, 2020.

STUDY SELECTION

Case-control studies reporting inflammatory mediators' levels in BD and controls.

DATA EXTRACTION AND SYNTHESIS

Summary distribution measures of circulating CRP, IL-1β, IL-6, TNF-α in participants with BD and control groups were extracted. Random-effects multivariate meta-analyses were conducted based on individual study/mediator effect sizes (Hedge's g).

MAIN OUTCOMES AND MEASURES

Co-primary outcomes were inflammatory mediators' levels (Hedge's g) and variability (coefficient of variance ratio (CVR)) differences between participants with BD across the mood spectrum and controls.

RESULTS

Out of the initial 729 papers, 72 were assessed and then excluded after full-text review, and ultimately 53 studies were included in the systematic review, while 49 were included in the meta-analysis. The mean age was 36.96 (SD: 9.29) years, and the mean female percentage was 56.31 (SD: 16.61). CRP (g = 0.70, 95% CI 0.31-1.09, k = 37, BD = 2,215 vs HC = 3,750), IL-6 (g = 0.81, 95% CI 0.46-1.16, k = 45, BD = 1,956 vs HC = 4,106), TNF-α (g = 0.49, 95% CI 0.19-0.78, k = 49, BD = 2,231 vs HC = 3,017) were elevated in subjects with BD vs HC, but not IL-1β (g = -0.28, 95% CI -0.68-0.12, k = 4, BD = 87 vs HC = 66). When considering euthymic, depressive, and manic episodes separately, CRP and TNF-α were elevated in both depressive and manic episodes, but not in euthymia, while IL-6 remained elevated regardless of the disease state. No difference in CVR emerged for CRP, IL-1β, and TNF-α, while a lower CVR was observed for IL-6. When considering disease phases, CVR was higher in BD than in HCs for CRP during depressive episodes, lower for IL-6 during euthymia, and higher during manic episodes for CRP, IL-6, and TNF-α. Sensitivity analyses after excluding outliers identified with funnel plot visual inspection, low-quality studies, and considering only studies matched per body mass index confirmed the main results. Meta-regression showed that age (IL-6, TNF-α), gender (CRP), duration of illness (CRP) moderated elevated individual inflammatory levels.

CONCLUSIONS AND RELEVANCE

Peripheral pro-inflammatory marker elevations were confirmed in BD. CRP and TNF-α could represent state markers, as they were only elevated during mood episodes, while IL-6 appeared to be a trait marker for BD. Increased variability of specific inflammatory mediators in specific disease active states suggests that a subset of subjects with BD may exhibit elevated inflammation as part of a manic or depressive episode.

Infliximab and tocilizumab reduce anxiety-like behavior, improve cognitive performance and reverse neuropathological alterations in juvenile rats with severe autoimmune arthritis

Several studies have demonstrated that rheumatic diseases, including Juvenile Idiopathic Arthritis (JIA), are associated with anxiety-like behavior and a cognitive decline. Infliximab, a Tumor Necrosis Factor-alpha (TNF-a) inhibitor, and tocilizumab, an antibody against Interleukin-6 (IL-6) receptor, are commonly used in the treatment of JIA. Here, we aimed to evaluate the effects of infliximab and tocilizumab on anxiety symptoms and cognitive function in a juvenile model of severe autoimmune arthritis. We found that both infliximab and tocilizumab improved anxiety-like behavior in the elevated-plus and elevated-zero maze tests. Tocilizumab, also, improved cognitive performance in the passive avoidance and olfactory social memory tests. Histological examination showed that anti-cytokine treatment reversed the histopathological alterations in the brain induced by arthritis. Further, infliximab and tocilizumab treatment increased Brain-Derived Neurotrophic Factor (BDNF) expression in the hippocampal and amygdaloid area of rat brain. In summary, our findings provide evidence that infliximab and tocilizumab have a beneficial effect on anxiety-like behavior and cognitive function and alleviate neuropathological alterations in a juvenile rat model of severe arthritis, suggesting that inhibition of TNF-a and IL-6 in the periphery, may be associated with a mood and memory enhancement in JIA patients.

Interleukin-10 level is associated with post-stroke depression in acute ischaemic stroke patients

BACKGROUND

Interleukin-10 (IL-10) is a pathophysiological factor in acute ischaemic stroke (AIS) and is relevant to mood disorders after stroke. We evaluated the predictive value of IL-10 in patients with post-stroke depression (PSD).

METHODS

A total of 350 stroke patients were recruited at baseline, and 151 AIS patients were screened and completed a 1-month follow-up. Serum IL-10 levels were measured within 24 h of admission. We used the 17-item Hamilton Depression Scale (HAMD-17) to evaluate depression symptoms; PSD was defined as an HAMD score ≥ 7.

RESULTS

Fifty-one (33.8%) patients showed a more serious stroke degree, larger infarction volume, and poorer daily life activities and prognosis (P < 0.05) and were diagnosed with PSD at the 1-month follow-up. Their IL-10 level decreased significantly compared to the non-PSD group (P < 0.001). After adjusting for confounders, IL-10 could be used as an independent predictor for PSD with an adjusted odds ratio (OR) of 0.615 (95% CI 0.410-0.923, P = 0.019). In addition, the optimal cut-off value of IL-10 was 0.615 pg/mL based on an area under the receiver operating characteristic curve of 0.692 (95% CI 0.604-0.781, P < 0.001), demonstrating that IL-10 could predict the occurrence of PSD. Moreover, IL-10 was an indicator of stroke severity, living ability, and functional outcomes (P < 0.05).

LIMITATIONS

IL-10 was only measured upon admission; dynamic changes need to be further monitored. This was also a single-centre study with a relatively small sample.

CONCLUSIONS

Lower IL-10 levels may be used to predict PSD.

Effects of long-term infliximab and tocilizumab treatment on anxiety-like behavior and cognitive function in naive rats

BACKGROUND

Circulating cytokines have been proposed to be implicated in the development of mood disorders and cognitive impairment. This study aims to examine the effect of chronic treatment with infliximab, a tumor necrosis factor-alpha (TNF-alpha) inhibitor, and tocilizumab, an antibody against interleukin-6 (IL-6) receptor on anxiety-like behavior and cognitive function.

METHODS

Twenty-eight male, Wistar rats were randomly allocated into negative control, vehicle, infliximab and tocilizumab groups. After 8 weeks of intraperitoneal drug administration, rats performed the elevated-plus maze, the elevated-zero maze, the olfactory social memory and the passive avoidance tests. Brain sections at the level of the hippocampus, the amygdala and the prefrontal cortex were histologically examined. Finally, hippocampal and amygdaloid brain-derived neurotrophic factor (BDNF) expression was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

RESULTS

Infliximab group exhibited a significantly higher number of entries and time spent into the open arms of the mazes, showing a lower level of anxiety. In the olfactory social memory test, tocilizumab significantly increased the ratio of interaction. Both infliximab- and tocilizumab-treated animals had a significantly lower latency time in the passive avoidance test that suggests an improved memory. Histological examination revealed similar morphology and neuronal density between groups. BDNF expression levels were significantly increased in the groups receiving anti-cytokine treatment.

CONCLUSIONS

Our findings suggest that long-term peripheral TNF-alpha and IL-6 inhibition improves anxiety and cognitive function in rats and leads to an increased BDNF expression in the brain.

Infliximab and Tocilizumab Reduce Anxiety-Like Behaviour and Improve Cognitive Performance in a Juvenile Collagen-Induced Arthritis Rat Model

Anxiety disorders and cognitive decline are highly prevalent in rheumatic diseases, including Juvenile Idiopathic Arthritis (JIA). In this study, we investigated the effect of long-term treatment with infliximab and tocilizumab on anxiety-like behaviour and cognitive performance in a juvenile collagen-induced arthritis (CIA) rat model. Forty-nine rats with established moderate arthritis were randomly allocated into 7 equal groups: negative control, vehicle, methotrexate, infliximab, tocilizumab, methotrexate + infliximab and methotrexate + tocilizumab groups. Behavioural tests were performed to evaluate anxiety-like behaviour and cognitive function. Neuropathological changes were investigated by histological examination at the level of the hippocampus, the amygdala and the prefrontal cortex. Also, the expression of Brain-Derived Neurotrophic Factor (BDNF), a biomarker associated with neuronal survival and plasticity, was determined in the hippocampus and the amygdala by RT-qPCR. We found that both infliximab and tocilizumab reduced anxiety-like behaviour in the elevated-plus and elevated-zero maze tests. Tocilizumab, also, improved cognitive function in the olfactory social memory and passive avoidance tests. Anti-cytokine treatment reversed the histopathological changes in the brain induced by CIA. BDNF expression was higher in all treatment groups and especially those receiving monoclonal antibodies combined with methotrexate. Our data provide evidence that chronic infliximab and tocilizumab treatment reduces anxiety-like behaviour, improves cognitive function, reverses neuropathological changes and increases central BDNF expression in a juvenile arthritis rat model. These findings may be translated to humans to address behavioural comorbidities associated with JIA.

Can Molecular Biology Propose Reliable Biomarkers for Diagnosing Major Depression?

BACKGROUND

Modern medicine has provided considerable knowledge of the pathophysiology of mental disorders at the body, systemic, organ and neurochemical levels of the biological organization of the body. Modern clinical diagnostics of depression have some problems, that is why psychiatric society makes use of diagnostics and taxonomy of different types of depression by implemention of modern molecular biomarkers in diagnostic procedures. But up to now, there are no reliable biomarkers of major depressive disorder (MDD) and other types of depression.

OBJECTIVE

The purpose of this review is to find fundamentals in pathological mechanisms of depression, which could be a basis for development of molecular and genetic biomarkers, being the most feasible for clinical use.

METHOD

This review summarizes the published data using PubMed, Science Direct, Google Scholar and Scopus.

RESULTS

In this review, we summarized and discussed findings in molecular biology, genetics, neuroplasticity, neurotransmitters, and neuroimaging that could increase our understanding of the biological foundations of depression and show new directions for the development of reliable biomarkers. We did not find any molecular and genetic biomarker approved for the clinic. But the Genome-Wide Association Study method promises some progress in the development of biomarkers based on SNP in the future. Epigenetic factors also are a promising target for biomarkers. We have found some differences in the etiology of different types of atypical and melancholic depression. This knowledge could be the basis for development of biomarkers for clinical practice in diagnosis, prognosis and selection of treatment.

CONCLUSION

Depression is not a monoetiological disease. Many pathological mechanisms are involved in depression, thus up to now, there is no approved and reliable biomarker for diagnosis, prognosis and correction of treatment of depression. The structural and functional complexity of the brain, the lack of invasive technology, poor correlations between genetic and clinical manifestation of depression, imperfect psychiatric classification and taxonomy of subtypes of disease are the main causes of this situation. One of the possible ways to come over this situation can be to pay attention to the trigger mechanism of disease and its subtypes. Researchers and clinicians should focus their efforts on searching the trigger mechanism of depression and different types of it . HPA axis can be a candidate for such trigger in depression caused by stress, because it influences the main branches of disease: neuroinflammation, activity of biogenic amines, oxidative and nitrosative stress, epigenetic factors, metabolomics, etc. But before we shall find any trigger mechanism, we need to create complex biomarkers reflecting genetic, epigenetic, metabolomics and other pathological changes in different types of depression. Recently the most encouraging results have been obtained from genetics and neuroimaging. Continuing research in these areas should be forced by using computational, statistical and systems biology approaches, which can allow to obtain more knowledge about the neurobiology of depression. In order to obtain clinically useful tests, search for biomarkers should use appropriate research methodologies with increasing samples and identifying more homogeneous groups of depressed patients.

Inflammation-driven brain and gut barrier dysfunction in stress and mood disorders

Regulation of emotions is generally associated exclusively with the brain. However, there is evidence that peripheral systems are also involved in mood, stress vulnerability vs. resilience, and emotion‐related memory encoding. Prevalence of stress and mood disorders such as major depression, bipolar disorder, and post‐traumatic stress disorder is increasing in our modern societies. Unfortunately, 30%–50% of individuals respond poorly to currently available treatments highlighting the need to further investigate emotion‐related biology to gain mechanistic insights that could lead to innovative therapies. Here, we provide an overview of inflammation‐related mechanisms involved in mood regulation and stress responses discovered using animal models. If clinical studies are available, we discuss translational value of these findings including limitations. Neuroimmune mechanisms of depression and maladaptive stress responses have been receiving increasing attention, and thus, the first part is centered on inflammation and dysregulation of brain and circulating cytokines in stress and mood disorders. Next, recent studies supporting a role for inflammation‐driven leakiness of the blood–brain and gut barriers in emotion regulation and mood are highlighted. Stress‐induced exacerbated inflammation fragilizes these barriers which become hyperpermeable through loss of integrity and altered biology. At the gut level, this could be associated with dysbiosis, an imbalance in microbial communities, and alteration of the gut–brain axis which is central to production of mood‐related neurotransmitter serotonin. Novel therapeutic approaches such as anti‐inflammatory drugs, the fast‐acting antidepressant ketamine, and probiotics could directly act on the mechanisms described here improving mood disorder‐associated symptomatology. Discovery of biomarkers has been a challenging quest in psychiatry, and we end by listing promising targets worth further investigation.

The role of gene polymorphisms, and analysis of peripheral and central levels of interleukins in suicidal behavior: A systematic review

In terms of the physiological characteristics of suicidal behavior (SB) disorder, an increase inflammation response has been reported in these individuals. Therefore, the pro-inflammatory and anti-inflammatory activities of interleukins are adequate markers to research in order to understand the pathogenesis of SB. For that reason, the aim of this systematic review was to evaluate the role of interleukins in individuals with suicidal behavior disorder. A systematic search was performed in PubMed, Scopus and EBSCO databases up to July 2019. We used the words "interleukin" AND "suicide", "interleukin" AND "suicidal", and "IL-". Articles where interleukins concentrations were measured in individuals with SB and/or genetic studies addressing interleukins genes variants as possible markers to SB were included. A total of 54 articles were included. Articles that measured interleukin levels comprised 1111 cases and 1588 controls; whereas the genetic studies comprised 3082 cases and 5148 controls. These studies evaluated the concentrations of IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, sIL-2R in serum, plasma. The pro-inflammatory interleukins concentrations were higher in cases than in controls; however, we observed heterogeneity in the measurements and sample sources. Whereas, 9 polymorphisms of IL-1α, IL-1β, IL-6, IL-1β-8 genes were analyzed in association with suicide behavior disorder, though no conclusive outcomes were attained. Our results suggest that individuals with suicide risk undergo continuous stress that could trigger the release and circulation of pro-inflammatory interleukins and therefore their concentration in plasma. However, more studies are necessary in order to reach conclusively outcomes.

A Probiotic Lactobacillus gasseri Alleviates Escherichia coli-Induced Cognitive Impairment and Depression in Mice by Regulating IL-1β Expression and Gut Microbiota

Excessive expression of interleukin (IL)-1β in the brain causes depression and cognitive dysfunction. Herein, we investigated the effect of Lactobacillus gasseri NK109, which suppressed IL-1β expression in activated macrophages, on Escherichia coli K1-induced cognitive impairment and depression in mice. Germ-free and specific pathogen-free mice with neuropsychiatric disorders were prepared by oral gavage of K1. NK109 alleviated K1-induced cognition-impaired and depressive behaviors, decreased the expression of IL-1β and populations of NF-κB⁺/Iba1⁺ and IL-1R⁺ cells, and increased the K1-suppressed population of BDNF⁺/NeuN⁺ cells in the hippocampus. However, its effects were partially attenuated by celiac vagotomy. NK109 treatment mitigated K1-induced colitis and gut dysbiosis. Tyndallized NK109, even if lysed, alleviated cognitive impairment and depression. In conclusion, NK109 alleviated neuropsychiatric disorders and colitis by modulating IL-1β expression, gut microbiota, and vagus nerve-mediated gut-brain signaling.

Cytokine storm induced new onset depression in patients with COVID-19. A new look into the association between depression and cytokines -two case reports

Background

Depression appears to be a common complication in patients during and post–COVID-19 infection. Understanding the mechanism of action of cytokines such as interleukin-6, interleukin-10 and others in depression and in cytokine storm syndrome, the core component of COVID- 19, could shine a new light on future treatment options for both disorders.

Objective

This review demonstrates the role of interleukins in COVID-19 pathogenesis and their role in depression.

Results

We described cases we have treated as an example for the dual role interleukins have in COVID-19 infection and depression and reviewed approximately 70 articles focusing on the role of interleukins in cytokine storm syndrome and depression.

Conclusion

This review highlights the key features of cytokines in both diseases. As the scientific community has more time to recover and process the effect of the current pandemic, we believe that additional research will pave the way to diverse pathways to treat depression in these patient and others.

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This review highlights the key features of cytokines in both diseases.

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We believe that additional research will pave the way to diverse pathways to treat depression in COVID-19 patients and others.

Long-Term Exposure to Ceftriaxone Sodium Induces Alteration of Gut Microbiota Accompanied by Abnormal Behaviors in Mice

Background: Growing evidence points out that a disturbance of gut microbiota may also disturb the gut–brain communication. However, it is not clear to what extent the alteration of microbiota composition can modulate brain function, affecting host behaviors. Here, we investigated the effects of gut microbiota depletion on emotional behaviors.

Methods: Mice in the experimental group were orally administered ceftriaxone sodium solution (250 mg/ml, 0.2 ml/d) for 11 weeks. The open-field test and tail-suspension test were employed for the neurobehavioral assessment of the mice. Fecal samples were collected for 16s rDNA sequencing. The serum levels of cytokines and corticosterone were quantified using enzyme-linked immunosorbent assays. The immunohistochemistry method was used for the detection of brain-derived neurotrophic factor (BDNF) and c-Fos protein.

Results: The gut microbiota for antibiotic-treated mice showed lower richness and diversity compared with normal controls. This effect was accompanied by increased anxiety-like, depression-like, and aggressive behaviors. We found these changes to be possibly associated with a dysregulation of the immune system, abnormal activity of the hypothalamic-pituitary-adrenal axis, and an alteration of neurochemistry.

Conclusions: The findings demonstrate the indispensable role of microbiota in the gut–brain communication and suggest that the absence of conventional gut microbiota could affect the nervous system, influencing brain function.

Psycho-Neuroendocrine-Immune Interactions in COVID-19: Potential Impacts on Mental Health

Coronavirus disease 2019 (COVID-19) is caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The impacts of the disease may be beyond the respiratory system, also affecting mental health. Several factors may be involved in the association between COVID-19 and psychiatric outcomes, such as fear inherent in the pandemic, adverse effects of treatments, as well as financial stress, and social isolation. Herein we discuss the growing evidence suggesting that the relationship between SARS-CoV-2 and host may also trigger changes in brain and behavior. Based on the similarity of SARS-CoV-2 with other coronaviruses, it is conceivable that changes in endocrine and immune response in the periphery or in the central nervous system may be involved in the association between SARS-CoV-2 infection and impaired mental health. This is likely to be further enhanced, since millions of people worldwide are isolated in quarantine to minimize the transmission of SARS-CoV-2 and social isolation can also lead to neuroendocrine-immune changes. Accordingly, we highlight here the hypothesis that neuroendocrine-immune interactions may be involved in negative impacts of SARS-CoV-2 infection and social isolation on psychiatric issues.

Hypothesis: bipolar disorder is an Epstein-Barr virus-driven chronic autoimmune disease - implications for immunotherapy

Bipolar disorder (BD) is a chronic disease characterised by episodes of major depression and episodes of mania or hypomania, with a worldwide prevalence of 2.4%. The cause of BD is unknown. Here, I propose the hypothesis that BD is a chronic autoimmune disease caused by Epstein–Barr virus (EBV) infection of autoreactive B cells. It is postulated that EBV‐infected autoreactive B cells accumulate in the brain where they provide costimulatory survival signals to autoreactive T cells and differentiate into plasma cells producing pathogenic autoantibodies targeting brain components such as the N‐methyl‐D‐aspartate receptor. It is also proposed that the accumulation of EBV‐infected autoreactive B cells in the brain is a consequence of a genetically determined defect in the ability of CD8⁺ T cells to control EBV infection. The theory is supported by studies indicating that autoimmunity, EBV infection and CD8⁺ T‐cell deficiency all have roles in the pathogenesis of BD. According to the hypothesis, BD should be able to be treated by EBV‐specific T‐cell therapy and to be prevented by vaccination against EBV in early childhood. Exposure to sunlight or appropriate artificial light should also be beneficial in BD by augmenting CD8⁺ T‐cell control of EBV infection.

A Specific Inflammatory Profile Underlying Suicide Risk? Systematic Review of the Main Literature Findings

Consistent evidence indicates the association between inflammatory markers and suicidal behavior. The burden related to immunological differences have been widely documented in both major affective disorders and suicidal behavior. Importantly, abnormally elevated pro-inflammatory cytokines levels have been reported to correlate with suicidal behavior but whether and to what extent specific inflammatory cytokines abnormalities may contribute to our understanding of the complex pathophysiology of suicide is unknown. The present manuscript aimed to systematically review the current literature about the role of pro-inflammatory cytokines in suicidal behavior. Most studies showed a link between abnormally higher interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF), kynurenic acid (KYN), and lower IL-2, IL-4, and interferon (IFN)-γ levels in specific brain regions and suicidal behavior. Unfortunately, most studies are not able to exclude the exact contribution of major depressive disorder (MDD) as a mediator/moderator of the link between inflammatory cytokines abnormalities and suicidal behavior. The association between suicidal patients (both suicide attempters or those with suicidal ideation) and the altered immune system was documented by most studies, but this does not reflect the existence of a specific causal link. Additional studies are needed to clarify the immune pathways underlying suicidal behavior.

Altered serum interleukin-7 and interleukin-10 are associated with drug-free major depressive disorder

BACKGROUND

Abnormal expression of inflammatory cytokines in major depressive disorder (MDD) suggests the activation of an inflammatory process. The pattern of alterations in cytokine levels is still ambiguous. The present study aimed to evaluate interleukin-7 (IL-7) and interleukin-10 (IL-10) for their involvement in the pathophysiology of MDD and determine their relationships with depression risk.

METHODS

The study included 166 medication-free subjects: 84 MDD patients and 82 sex- and age-matched healthy controls (HCs). A qualified psychiatrist diagnosed patients and evaluated controls based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5). Hamilton depression rating scale (Ham-D) was used to measure the severity of depression in MDD patients. Serum IL-7 and IL-10 levels were measured using enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

Compared with HCs, the serum levels of IL-7 were significantly decreased, whereas that of IL-10 increased in MDD patients. Moreover, the severity of depression is correlated with the altered levels of IL-7 and IL-10 in MDD patients. We found a negative correlation between IL-7 and Hamilton depression rating (Ham-D) scores (r = -0.580, p < 0.05), whereas there was a positive correlation between IL-10 and Ham-D scores (r = 0.555, p < 0.05).

CONCLUSIONS

The altered levels of serum IL-7 and IL-10 in MDD patients may represent a homeostatic mechanism that enhances the inflammatory process during depression. The alterations of these cytokine levels in MDD and their association with the severity of depression support them as promising, but there may still be controversial factors for understanding the pathophysiology of depression.

Oxidative Stress-Related Endothelial Damage in Vascular Depression and Vascular Cognitive Impairment: Beneficial Effects of Aerobic Physical Exercise

Oxidative stress- (OS-) related endothelial damage is involved in the occurrence and progression of several disorders, such as vascular depression and dementia. It has been reported that moderate, aerobic, physical exercise could reduce OS and inflammation, thus limiting the cardiovascular risk factors while improving endothelial homeostasis, mood, and cognition. In this review, we will discuss about the role of OS and OS-related endothelial damage in vascular depression and vascular cognitive impairment. Then, we will comment on the effects of physical exercise on both disorders.