Pro- and anti-inflammatory cytokines, but not CRP, are inversely correlated with severity and symptoms of major depression

Exploring the multiverse: the impact of researchers' analytic decisions on relationships between depression and inflammatory markers

In recent years, a replication crisis in psychiatry has led to a growing focus on the impact of researchers' analytic decisions on the results from studies. Multiverse analyses involve examining results across a wide array of possible analytic decisions (e.g., log-transforming variables, number of covariates, or treatment of outliers) and identifying if study results are robust to researchers' analytic decisions. Studies have begun to use multiverse analysis for well-studied relationships that have some heterogeneity in results/conclusions across studies.We examine the well-studied relationship between peripheral inflammatory markers (PIMs; e.g., white blood cell count (WBC) and C-reactive protein (CRP)) and depression severity in the large NHANES dataset (n = 25,962). Specification curve analyses tested the impact of 9 common analytic decisions (comprising of 58,000+ possible combinations) on the association of PIMs and depression severity. Relationships of PIMs and total depression severity are robust to analytic decisions (based on tests of inference jointly examining effect sizes and p-values). However, moderate/large differences are noted in effect sizes based on analytic decisions and the majority of analyses do not result in significant findings, with the percentage of analyses with statistically significant results being 46.1% for WBC and 43.8% for CRP. For associations of PIMs with specific symptoms of depression, some associations (e.g., sleep, appetite) in males (but not females) were robust to analytic decisions. We discuss how multiverse analyses can be used to guide research and also the need for authors, reviewers, and editors to incorporate multiverse analyses to enhance replicability of research findings.

Cytokine associated with severity of depressive symptoms in female nurses in Korea

Background

Depression has been associated with the risk of developing physical illnesses and diseases. Inflammatory hypotheses of immunoactive and dysregulated cytokine production have been proposed to describe this association; however, data pertaining to the high prevalence of depression among nurses are limited.

Objective

This study aimed to use a comprehensive immune-profiling approach to determine whether an abnormal profile of circulating cytokines could be identified in nurses with self-reported depression and whether this profile is associated with the severity of depression.

Methods

We investigated a cohort of 157 female nurses in Korea. The self-report Patient Health Questionnaire was used to measure the depression levels of nurses. In addition, peripheral blood samples were collected and used to measure the cytokine profile using the Luminex multiplexing system. Generalized gamma regression analyses were conducted to evaluate the association between cytokine and depressive symptoms.

Results

Regarding severity of depressive symptoms, 28.0% of nurses had moderately severe depression while 9.6% had severe depression. Moderately-severe depressive symptoms in nurses were associated with elevated levels of interleukin-6 (B = 0.460, p = 0.003), interleukin-8 (B = 0.273, p = 0.001), and interleukin-18 (B = 0.236, p = 0.023), whereas interferon-gamma levels (B = -0.585, p = 0.003) showed the opposite profile. Participants with severe depressive symptoms presented decreased interferon-gamma levels (B = -1.254, p < 0.001).

Conclusion

This study demonstrated that proinflammatory cytokines were associated with depression among nurses. This calls for early detection and intervention, considering the mechanisms linking depression to physical illness and disease.

Enlarged cross-sectional area of the left vagus nerve in patients with major depressive disorder

Purpose

Autonomic dysfunction and a chronic low-grade inflammation are supposed to play a role in the etiology of major depressive disorder (MDD). The vagus nerves (VN) form a major part of the parasympathetic nervous system and of the gut-brain axis. They are supposed to exert anti-inflammatory and epithelial barrier protective effects in the gut. A reduced vagal activity was described in patients with MDD. We aimed to examine the VN in patients with MDD with high-resolution ultrasound (HRUS) and hypothesized that the cross-sectional area (CSA) and the echogenicity of the VNs were altered in comparison to healthy controls.

Materials and methods

The echogenicity (gray scale mean) and the CSA of the cervical VNs at the level of the thyroid gland and both median nerves were examined with HRUS in 50 patients with MDD and 50 matched healthy controls.

Results

The left VN-CSA was significantly larger in the MDD group compared to the control group (1.7 ± 0.4 mm2 versus 1.5 ± 0.4 mm2; p = 0.045). The CSA of the right VN and both median nerves (MN) were similar between groups. In MDD subgroup analyses, recurrent depressive disorders were the main contributing factor for the left VN-CSA enlargement. Echogenicity was not altered in the VN and MN between groups.

Conclusion

The enlargement of the left VN-CSA in patients with MDD, and especially in these patients with recurrent depressive disorders, might turn out as a promising imaging biomarker. Longitudinal studies are warranted to examine whether the VNs-CSA change in the course of MDD.

S100B Protein but Not 3-Nitrotyrosine Positively Correlates with Plasma Ammonia in Patients with Inherited Hyperammonemias: A New Promising Diagnostic Tool?

Individuals with inherited hyperammonemias often present developmental and intellectual deficiencies which are likely to be exaggerated by hyperammonemia episodes in long-term outcomes. In order to find a new, systemic marker common to the course of congenital hyperammonemias, we decided to measure the plasma level of S100 calcium-binding protein B (S100B), which is associated with cerebral impairment. Further, we analyzed three mechanistically diverged but linked with oxidative-nitrosative stress biochemical parameters: 3-nitrotyrosine (3-NT), a measure of plasma proteins' nitration; advanced oxidation protein products (AOPP), a measure of protein oxidation; and glutathione peroxidase (GPx) activity, a measure of anti-oxidative enzymatic capacity. The plasma biomarkers listed above were determined for the first time in congenital hyperammonemia. Also, the level of pro- and anti-inflammatory mediators (i.e., IL-12, IL-6, IL-8, TNF-α, IL-1β, and IL-10) and chemokines (IP-10, MCP-1, MIG, and RANTES) were quantified. S100B was positively correlated with plasma ammonia level, while noticeable levels of circulating 3-NT in some of the patients' plasma did not correlate with ammonia concentration. Overall, the linear correlation between ammonia and S100B but not standard oxidative stress-related markers offers a unique perspective for the future identification and monitoring of neurological deficits risk-linked with hyperammonemia episodes in patients with inherited hyperammonemias. The S100B measure may support the development of therapeutic targets and clinical monitoring in these disorders.

Hybrid molecules combining GABA-A and serotonin 5-HT6 receptors activity designed to tackle neuroinflammation associated with depression

There is clear evidence that the presence of inflammatory factors and impaired GABA-ergic neurotransmission in depressed patients is associated with poor clinical outcome. We designed hybrid molecules, bearing the GABA molecule assembled with chemical fragments that interact with the serotonin 5-HT₆ receptor. Such a combination aimed to curb neuroinflammation, remodel GABA-ergic signaling, and provide antidepressant-like activity. The most promising hybrid 3B exerted nanomolar affinity for 5-HT₆ receptors and exerted agonistic properties on GABA-A receptors. Developability studies conferred that 3B exerted favorable drug-like properties and optimal brain penetration. In in vivo studies, 3B exerted robust antidepressant-like activity and proved to be highly effective in reducing levels of oxidative stress markers and the pro-inflammatory cytokine IL-6. The inetersting pharmacological profile of 3B makes it a promising candidate for further development for depression associated with neuroinflammation.

Pre-treatment plasma cytokine levels as potential predictors of short-term remission of depression

OBJECTIVES

The response to antidepressants varies significantly among individuals and is difficult to predict before treatment. In this randomised control trial, we explored cytokines that correlate with the therapeutic effect of mirtazapine (MIR) and selective serotonin reuptake inhibitors (SSRIs) and whether they could be predictors of remission for each antidepressant.

METHODS

Plasma cytokines, such as tumour necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were assayed in 95 participants before medication and assayed by the enzyme-linked immunosorbent assay. The Hamilton Rating Scale for Depression assessed depressive symptoms over 4 weeks.

RESULTS

In the SSRI group, the baseline GM-CSF level was significantly higher in the remission group than in the non-remission group (p = .022). In the MIR group, the baseline level of TNF-α was significantly higher (p = .039) and IL-2 was lower (p = .032) in the remission group than in the non-remission group. In patients prescribed with MIR, the cut-off values of TNF-α (10.035 pg/mL) and IL-2 (1.170 pg/mL) calculated from the receiver operating characteristic curve suggested that the remission rate, which corresponds to a positive predictive value, could be increased from 31.3% to 60.0% and 50.0%, respectively. For those prescribed with SSRIs, the remission rate was 37.0% and using the cut-off value of GM-CSF (0.205 pg/mL), the remission rate could be almost doubled to 70%.

CONCLUSIONS

Our study shows that pre-treatment plasma concentrations of TNF-α, IL-2, and GM-CSF may suggest the predictability of remission by SSRIs or MIR.

Inflammatory Cytokines, but Not Dietary Patterns, Are Related to Somatic Symptoms of Depression in a Sample of Women

Background

Depression is a heterogenous disorder with both cognitive and somatic symptom dimensions that may differentially relate to systemic inflammation. Diet, which has the potential to modulate both inflammation levels and mood, is yet to be studied within the context of individual depression dimensions. This study examined the associations between inflammatory cytokines and dietary patterns with depressive symptom dimension profiles among a sample of women recruited in a non-clinical setting.

Methods

Inflammatory cytokines (IL-6 and TNF-α), inflammatory diet (Diet Inflammatory Index; DII), and depressive symptoms (Beck Depression Inventory-II; BDI-II) were measured in 136 females (M age = 22.01 ± 4.02, range 18-59 years). Multiple linear regressions were used to investigate the relationships between inflammatory cytokines and diet with self-reported cognitive, somatic, and total depressive symptoms, adjusting for demographic factors.

Results

Findings showed that increased somatic dimension scores were positively associated with IL-6 (ß = 0.273, p = 0.002) and TNF-α (ß = 0.215, p = 0.017), but not inflammatory diet (p = 0.300). Total BDI-II scores were only positively associated with IL-6 (ß = 0.221, p = 0.012), and cognitive dimension scores were not associated with any inflammation measures.

Conclusions

These findings contribute to existing evidence that inflammatory cytokines are associated with the somatic symptoms of depression. Inflammatory diet index was not associated with depression measures.

Jia Wei Xiao Yao San ameliorates chronic stress-induced depression-like behaviors in mice by regulating the gut microbiome and brain metabolome in relation to purine metabolism

BACKGROUND

The pathogenesis of depression remains largely unknown. Accumulating evidence demonstrates the existence of a complex relationship between gut microbiome composition and brain functions. Jia Wei Xiao Yao San (JWXYS) is considered a potential antidepressant. However, the pharmacological mechanisms of JWXYS have not yet been clarified.

PURPOSE

This study aimed to explore the effects of JWXYS on chronic stress-induced depression-like behaviors in mice.

METHODS

A chronic restraint stress mouse model of depression was established. JWXYS was administered, and the responses of these mice to treatment were evaluated through several behavioral tests. The activity of astrocytes and microglia was detected by specific fluorescent labels. Inflammatory cytokines were quantified in intestinal and cerebral tissues. An integrated approach with full-length 16S rRNA sequencing and different types of untargeted metabolomics was conducted to investigate the relationship between the gut microbiome at the species level, metabolic brain functions, and JWXYS.

RESULTS

We found that behavioral symptoms were associated with the relative abundance of Lactobacillus animalis. After JWXYS treatment, the relative abundance of Ileibacterium valens with enzymes potentially involved in purine metabolism was also described. The activation of astrocytes and microglia was negatively correlated with the relative abundance of L. animalis. Combined with network pharmacological analysis, several targets predicted based on JWXYS treatment focused on purine metabolism, which was also enriched from cerebral metabolites regulated by JWXYS.

CONCLUSION

Our study suggests that L. animalis is involved in depression-like behaviors in mice. JWXYS increases the abundance of I. valens with potential enzymes in relation to cerebral purine metabolism, which is positively correlated with the activation of astrocytes in the amygdala.

Neurobiological Highlights of Cognitive Impairment in Psychiatric Disorders

This review is focused on several psychiatric disorders in which cognitive impairment is a major component of the disease, influencing life quality. There are plenty of data proving that cognitive impairment accompanies and even underlies some psychiatric disorders. In addition, sources provide information on the biological background of cognitive problems associated with mental illness. This scientific review aims to summarize the current knowledge about neurobiological mechanisms of cognitive impairment in people with schizophrenia, depression, mild cognitive impairment and dementia (including Alzheimer's disease).The review provides data about the prevalence of cognitive impairment in people with mental illness and associated biological markers.

Are serum levels of inflammatory markers associated with the severity of symptoms of bipolar disorder?

BACKGROUND

To explore the relationship between serum levels of inflammatory markers and symptomatic severity of bipolar disorder (BD).

MATERIALS AND METHODS

A cross-sectional study was conducted on 126 BD patients with current depressive episode (BDD), 102 BD patients with current mixed or (hypo)manic episode (BDM) and 94 healthy controls (HC). All participants were drug-naïve and had no current active physical illness associated with inflammatory response or history of substance abuse. Fasting serum levels of CRP, leptin (LEP), adiponectin (ADP), visfatin (VIS), TNF-α, IL-2, IL-6, IL-10, IL-17), and monocyte chemoattractant protein-1 (MCP-1) were measured with enzyme-linked immunosorbent assay (ELISA). Symptomatic severity of BD was assessed with HAMD-17 and YMRS. Generalized linear model was used to determine the association between the serum levels of inflammatory markers and symptomatic severity of BD.

RESULTS

The serum levels of IL-6, IL-10 and IL-17, and the IL-6/IL-10 ratio were significantly lower in mild BDD than in HC. In moderate BDD, the serum levels of MCP, IL-6 and IL-17 were significantly lower than in HC. In severe BDD, the serum level of ADP, MCP-1, IL-10 and IL-17and the IL-17/IL-10 ratio were significantly lower than in HC. The serum levels of TNF-α and the IL-6/IL-10 ratio were significantly higher in mild BDM than in HC. In moderate BDM, the serum level of VIS, IL-2, and IL-17 were significantly higher than in HC, but the IL-6/IL-10 ratio was significantly lower than in control. In severe BDM, the serum levels of IL-6 and IL-17 and the ratios of IL-6/IL-10 and IL-17/IL-10 were significantly lower than in HC, but the neutrophil/lymphocyte ratio was significantly higher than in HC.

CONCLUSION

In BDD, immune-inhibition is persistently predominant, while in mild-to-moderate BDM, immune system is activated but inhibited in severe BDM. The dynamic change of serum inflammatory markers suggests that alteration of peripheral inflammatory markers in BD is state-dependent instead of trait-marked.

Association Between Systemic Inflammation and Individual Symptoms of Depression: A Pooled Analysis of 15 Population-Based Cohort Studies

OBJECTIVE

Evidence from anti-inflammatory drug trials for the treatment of depression has been inconsistent. This may be ascribed to the differing symptom-specific effects of inflammation. Accordingly, the authors explored the associations between systemic inflammation and an array of individual symptoms of depression across multiple studies.

METHODS

This random-effects pooled analysis included 15 population-based cohorts and 56,351 individuals age 18 years and older. Serum or plasma concentrations of C-reactive protein (CRP) and interleukin-6 (IL-6) were measured at baseline. Using validated self-report measures, 24 depressive symptoms were ascertained in 15 cross-sectional studies, and, in seven cohorts, were also assessed at follow-up (mean follow-up period, 3.2 years).

RESULTS

The prevalence of depressive symptoms ranged from 1.1% (suicidal ideation) to 21.5% (sleep problems). In cross-sectional analyses, higher concentrations of CRP were robustly associated with an increased risk of experiencing four physical symptoms (changes in appetite, felt everything was an effort, loss of energy, sleep problems) and one cognitive symptom (little interest in doing things). These associations remained after adjustment for sociodemographic variables, behavioral factors, and chronic conditions; in sex- and age-stratified analyses; in longitudinal analyses; when using IL-6 as the inflammatory marker of interest; in depressed individuals; and after excluding chronically ill individuals. For four exclusively emotional symptoms (bothered by things, hopelessness about the future, felt fearful, life had been a failure), the overall evidence was strongly against an association with inflammation.

CONCLUSIONS

These findings suggest symptom-specific rather than generalized effects of systemic inflammation on depression. Future trials exploring anti-inflammatory treatment regimens for depression may benefit from targeting individuals presenting with symptom profiles characterized by distinct inflammation-related physical and cognitive symptoms.

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.

Effects of antidepressant drug therapy with or without physical exercise on inflammatory biomarkers in major depressive disorder: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To conduct a systematic review and meta-analysis of the effects of antidepressant drug therapy (with or without physical exercise) on peripheral inflammatory markers in patients with major depressive disorder (MDD).

METHODS

MEDLINE, PyscINFO, Embase, and Google Scholar databases were searched until May 2020. Randomized trials that measured at least one inflammatory biomarker and included adult outpatients with MDD under antidepressant drug therapy (any drug) with or without physical exercise (any modality) were eligible. Results were summarized using the standardized mean difference (SMD) with 95% confidence intervals (95% CI) under a random-effects model. The Cochrane risk of bias tool (2010) was used to evaluate the risk of bias in the included trials.

RESULTS

Sixty-three trials were identified, encompassing data from 3482 patients, and 20 investigated biomarkers. Trials had biases across multiple domains, rising concerns primarily to selection bias/performance bias/detection bias/attrition bias. SMDs between pre- and post-results indicated a significant reduction in the levels of IL-2 (SMD, - 0.25; 95% CI, - 0.41 to - 0.09, P = 0.002), IL-6 (SMD, - 0.19; 95% CI, - 0.35 to - 0.025, P = 0.024), IL-10 (SMD, - 0.32; 95% CI, - 0.57 to - 0.07, P = 0.011), and serum cortisol (SMD, - 0.35; 95% CI, - 0.58 to - 0.12, P = 0.002). Evidence supporting the influence of physical exercise combined with antidepressant drugs on peripheral inflammatory markers in MDD is sparse and heterogeneous.

CONCLUSION

There is some evidence that antidepressant drug therapy is associated with an overall positive reduction in inflammatory markers, but the evidence is heterogeneous. Further research linking how inflammatory biomarkers modulate physiology related to antidepressant response is required.

TRIAL REGISTRATION

CRD42020220735.

Potential biomarkers of major depression diagnosis and chronicity

BACKGROUND

Molecular biomarkers are promising tools to be routinely used in clinical psychiatry. Among psychiatric diseases, major depression disorder (MDD) has gotten attention due to its growing prevalence and morbidity.

METHODS

We tested some peripheral molecular parameters such as serum mature Brain-Derived Neurotrophic Factor (mBDNF), plasma C-Reactive Protein (CRP), serum cortisol (SC), and the salivary Cortisol Awakening Response (CAR), as well as the Pittsburgh sleep quality inventory (PSQI), as part of a multibiomarker panel for potential use in MDD diagnosis and evaluation of disease's chronicity using regression models, and ROC curve.

RESULTS

For diagnosis model, two groups were analyzed: patients in the first episode of major depression (MD: n = 30) and a healthy control (CG: n = 32). None of those diagnosis models tested had greater power than Hamilton Depression Rating Scale-6. For MDD chronicity, a group of patients with treatment-resistant major depression (TRD: n = 28) was tested across the MD group. The best chronicity model (p < 0.05) that discriminated between MD and TRD included four parameters, namely PSQI, CAR, SC, and mBDNF (AUC ROC = 0.99), with 96% of sensitivity and 93% of specificity.

CONCLUSION

These results indicate that changes in specific biomarkers (CAR, SC, mBDNF and PSQI) have potential on the evaluation of MDD chronicity, but not for its diagnosis. Therefore, these findings can contribute for further studies aiming the development of a stronger model to be commercially available and used in psychiatry clinical practice.

Inflammation and the Association of Vitamin D and Depressive Symptomatology

Depression and vitamin D deficiency are major public health problems. The existing literature indicates the complex relationship between depression and vitamin D. The purpose of this study was to examine whether this relationship is moderated or mediated by inflammation. A community sample (n = 7162) from the LIFE-Adult-Study was investigated, for whom depressive symptoms were assessed via the German version of CES-D scale and serum 25-hydroxyvitamin D (25(OH)D) levels and inflammatory markers (IL-6 and CRP levels, WBC count) were quantified. Mediation analyses were performed using Hayes’ PROCESS macro and regression analyses were conducted to test moderation effects. There was a significant negative correlation between CES-D and 25(OH)D, and positive associations between inflammatory markers and CES-D scores. Only WBC partially mediated the association between 25(OH)D levels and depressive symptoms both in a simple mediation model (ab: −0.0042) and a model including covariates (ab: −0.0011). None of the inflammatory markers showed a moderation effect on the association between 25(OH)D levels and depressive symptoms. This present work highlighted the complex relationship between vitamin D, depressive symptoms and inflammation. Future studies are needed to examine the effect of vitamin D supplementation on inflammation and depressive symptomatology for causality assessment.

Mental Comorbidity in Rheumatic Diseases

In this review, we summarise the most relevant studies in a PubMed Search term “mental disorders and rheumatic disease” in the last 15 years. Mental disorders such as depression and anxiety are common in people with rheumatic diseases. Treating these comorbidities can improve the patientʼs quality of life. The high prevalence of symptoms of psychiatric disorders is a challenge for rheumatologists, especially with regard to the differentiation of possible psychiatric components in rheumatological diseases. Screening for psychiatric problems in patients with rheumatic diseases should be evaluated as soon as possible, as these can have a major influence on the perception of pain and physical functioning status from the outset. Mental health disorders are seen as a risk factor for poor patient outcomes, as patients may not adhere to medical treatments. The potential side effects of biological agents can increase patient anxiety and affect adherence to therapy. Therefore, interdisciplinary care would be of great advantage in the treatment of rheumatic patients with psychological comorbidities.

Relationship Between Serum Fibrinogen Level and Depressive Symptoms in an Adult Population with Spinal Cord Injury: A Cross-Sectional Study

PURPOSE

Depression is associated with an inflammatory immune response. There are minimal data regarding the association of inflammatory markers with depression in patients with spinal cord injury (SCI). We aimed to investigate the association of inflammatory markers with depression in middle-aged and elderly SCI patients.

METHODS

Data were obtained from the Midlife in the United States (MIDUS) study, a longitudinal study of a representative sample of the adult population. We analyzed the associations of serum levels of fibrinogen, interleukin-6, tumor necrosis factor-ɑ, and C-reactive protein with depressive symptoms.

RESULTS

The median participant age was 52.5 years; 44.9% of participants were men. Multivariate linear regression analyses showed that an increased serum fibrinogen level (Sβ = 0.114, p = 0.005) was associated with higher Centre for Epidemiological Studies-Depression (CES-D) scores after adjustment for age, sex, body mass index (BMI), ethnicity, education, marital status, smoking, alcohol use, exercise, perceived stress score, and cardiovascular disease (CVD). Multivariate logistic regression analysis showed that an increased serum fibrinogen level was independently associated with a history of depression (odds ratio [OR] = 1.240, 95% confidence interval [CI] = 1.103-1.997, p = 0.012) and depressive symptoms (OR = 1.884, 95% CI = 1.165-2.499, p < 0.001; CES-D score ≥ 16) after adjustment for confounding factors. Stratified analysis revealed that the association between serum fibrinogen level and depressive symptoms was affected by antidepressant use.

CONCLUSION

Serum fibrinogen level had a significantly positive association with depressive symptoms in middle-aged and elderly patients with SCI. Future longitudinal cohort studies should evaluate the possible use of serum fibrinogen for diagnosis of depression in SCI patients.

The Combination of Serum BDNF, Cortisol and IFN-Gamma Can Assist the Diagnosis of Major Depressive Disorder

PURPOSE

Misdiagnosis and ineffective treatment are common in major depressive disorder (MDD) in current clinical practice, while the combination of various serum proteins may assist the correct diagnosis. The study aimed to explore whether the combination of serum inflammatory, stress, and neurotrophic factors could be helpful for the diagnosis of MDD and to investigate the predictors associated with early symptom improvements.

PATIENTS AND METHODS

Baseline serum levels of C-reactive protein (CRP), interleukin (IL)-6, IL-10, IL-1beta, tumor necrosis factor (TNF)-alpha, interferon (INF)-gamma, cortisol, and brain-derived neurotrophic factor (BDNF) were detected in 30 MDD patients and 30 age- and gender-matched healthy controls. 17-item Hamilton Depression Rating Scale (HAMD-17) and Hamilton Anxiety Rating Scale (HAMA) were applied to assess symptoms both at baseline and two weeks after antidepressant treatment. Stepwise multiple linear regression was employed to identify the early efficacy predictors, and a logistic regression model was built with the above serum proteins. The area under the receiver operating characteristic (AUC) curve was calculated to evaluate the model's diagnostic power.

RESULTS

Multiple linear regression revealed that baseline scores of retardation (β = -0.432, P = 0.012) and psychological anxiety (β = -0.423, P = 0.014) factors were negatively associated with the reduction rate of HAMD-17. A simple and efficient diagnostic model using serum BDNF, cortisol, and IFN-gamma levels was established by the forward stepwise logistic regression, and the model achieved an AUC of 0.884, with 86.7% sensitivity and 83.3% specificity.

CONCLUSION

The results showed that combining serum BDNF, cortisol and IFN-gamma could aid the diagnosis of MDD, while baseline retardation and psychological anxiety may predict the poor early symptom improvement.

Inflammatory processes linked to major depression and schizophrenic disorders and the effects of polypharmacy in psychiatry: evidence from a longitudinal study of 279 patients under therapy

Over the past 2 decades, polypharmacy has become the de-facto standard of acute treatment in psychiatry where patients with psychiatric disorders receive a multiple medication regimen. There is growing evidence for a potential link between major psychiatric disorders and inflammatory processes. Combining these two aspects aims at avoiding polypharmacy attempts among patients with inflammatory activation through alternative treatment strategies. In this study, we addressed the following questions: (1) to what extent can polypharmacy be explained through the factors "diagnosis", "previous history", "severity at baseline", "age", "gender", and "psychiatrist in charge"; (2) what are the differences between polypharmacy and monotherapy regarding efficacy and side effect profiles; and (3) what amount of between-patient variance is explainable by the natural antibody immunoglobulin M (IgM) within each diagnostic group. This naturalistic longitudinal study was comprised of 279 patients under therapy with a clinical diagnosis of depressive (ICD-10: "F3x.x"; n = 195) or schizophrenic disorders (ICD-10: "F2x.x"; n = 84). The study protocol included (1) assessment of previous history by the SADS Syndrome Check List SSCL-16 (lifetime version); (2) repeated measurements over 5 weeks assessing the time course of improvement by the Hamilton Depression Scale HAM-D and the Positive and Negative Syndrome Scale PANSS, along with medication and unwanted side effects through the Medication and Side Effects Inventory MEDIS; and (3) the collection of blood samples from which DNA and serum were extracted. The association between inflammatory response system and psychiatric disorders was detailed by fitting multi-layer Neural Net (NN) models to the observed data ("supervised learning"). The same approach was used to set up prediction models of side effects. Our data showed that polypharmacy was omnipresent. Yet the various polypharmacy regimens had no advantage over monotherapy: we even found slightly larger baseline score reductions under monotherapy, independent of primary diagnoses and for comparable baseline severities. Most patients experienced unwanted side effects. The close link between side effects and treatment regimen was revealed by a linear model in which the mere number of drugs explained a significant (p < 0.001) proportion of the observed variance. As to the inflammatory response system: For the F2 patients, our NN model identified a 22.5% subgroup exhibiting a significant correlation of r = 0.746 (p = 0.0004) between global schizophrenia scores and IgM levels, along with a correct prediction of response of 94.4%, thus explaining 55.7% of the observed between-patient variance. For the F3 patients, our NN model identified a 19.6% subgroup exhibiting a significant correlation of r = 0.644 (p = 0.00003) between global depression scores and IgM levels, along a correct prediction of response of 89.6%, thus explaining 41.4% of the observed between-patient variance. Polypharmacy is omnipresent in today's acute treatment of psychiatric disorders. Given the large proportion of patients with unwanted side effects and the strong correlation between side effects and the number of drugs, polypharmacy approaches are not equally suited for every patient. In terms of efficacy, there are no advantages of polypharmacy over monotherapy. Most notably, our study appears to have cleared the way for the reliable identification of a subgroup of patients for whom the inflammatory response system is a promising target of therapeutic intervention.

An increase in IL-6 levels at 6-month follow-up visit is associated with SSRI-emergent suicidality in high-risk children and adolescents treated with fluoxetine

Major depressive disorder (MDD) is associated with alterations in circulatory cytokines, in adults as well as in children and adolescents. Administration of selective serotonin reuptake inhibitors (SSRIs) to MDD pediatric patients modifies cytokine levels. However, most studies only assessed changes over a short time period. In this study, we evaluated long-term effects of the SSRI fluoxetine (FLX) in children and adolescents treated for anxiety and/or MDD, including a high-risk group with pre-treatment suicidality. The study group included ninety-two patients (35 boys and 57 girls) with MDD and/or anxiety disorders, aged 13.90 ± 2.41 years. All patients were treated with FLX and followed for 6 months. The study group included children with pretreatment suicidality (high-risk group;N = 62) and without pretreatment suicidality (N = 30) according to the Columbia Suicide Severity Rating Scale. Plasma concentrations of TNFα, IL-6, and IL-1β were measured by enzyme linked immunosorbent assays before and after six months of treatment. IL-6 and IL-1β significantly increased as a factor of time after 6 months of treatment. The elevation was statistically significant confined to children with pretreatment suicidality. Within the children with pretreatment suicidality, IL-6 levels increased significantly after 6 months only in the children who developed SSRI-associated suicidality. To summarize, an increase in IL-6 levels after 6 months of treatment may be associated with SSRI-emergent suicidality in children with pretreatment suicidality. Further studies are needed to clarify the role and mechanism(s) of IL-6 in the pathogenesis of this life-threatening adverse event.

Circulating versus lipopolysaccharide-induced inflammatory markers as correlates of subthreshold depressive symptoms in older adults

Objectives: Circulating cytokines have been associated with depression, but their detection has limitations, which may be overcome by direct detection of intracellular cytokines (ICCs) after lipopolysaccharide (LPS) stimulation in vitro. This study compared circulating versus LPS-induced inflammatory markers as correlates of subthreshold depressive symptoms.Methods: Secondary data analysis of a cross-sectional insomnia study in healthy community-dwelling older adults was conducted. In 117 participants (≥55 years), plasma tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP) and in vitro LPS-induced monocyte production of IL-6 and TNF-α were assayed. Depressive symptoms were assessed using the clinician-rated Inventory of Depressive Symptomatology (IDS-C). Multivariate linear regression was conducted to test the associations between inflammatory markers and subthreshold depressive symptoms in the entire sample as well as in subgroups stratified into higher and lower inflammation levels.Results: LPS-induced TNF-α (adjusted β = 0.28, p = .04), IL-6 (0.29, p = .03) and TNF-α + IL-6 (0.43, p = .001) significantly positively correlated with subthreshold depressive symptoms only in higher inflammation subgroups. No circulating biomarkers positively correlated in any subgroups. In the entire sample, no biomarkers were significantly associated with subthreshold depressive symptoms.Conclusions: LPS-induced cytokines may be more sensitive correlates of subthreshold depressive symptoms than circulating cytokines, particularly in older adults with higher systemic inflammation.Clinical Trials Registry: ClinicalTrials.gov NCT00280020.

Different cytokine patterns associate with melancholia severity among inpatients with major depressive disorder

BACKGROUND

Six melancholic features (MFs) of the Hamilton Depression Rating Scale (HAM-D6) represent the construct of melancholia along a continuum of severity (from least to most severe: depressed mood, work and activities, somatic symptoms, psychic anxiety, guilty feelings, psychomotor retardation). We aimed to evaluate the association between these MFs and inflammatory cytokines (IC) in the blood.

METHODS

Each IC [interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2), IL-4, IL-6, IL-10, and IL-17] was associated with the HAM-D6 MFs of 139 severely depressed inpatients, using multiple linear regressions adjusted for covariates. Levels were compared with those of 100 healthy controls.

RESULTS

Depressed mood was associated with higher levels of IL-4 (β = 0.167; p = 0.041). Psychic anxiety: lower IL-17 levels (β = -0.173; p = 0.039). Guilt feelings: lower IL-2 levels (β = -0.168; p = 0.041) Psychomotor retardation: higher IL-6 levels (β = 0.195; p = 0.017). Depressed patients' TNF-α, INF-γ, and IL-4 levels were not significantly different from controls. Depressed patients' IL-2, IL-6, IL-10, and IL-17 levels were higher than those of controls (p <0.001).

CONCLUSION

Less severe MFs (depressed mood, psychic anxiety, and guilt feelings) were associated with an anti-inflammatory pattern (higher IL-4, lower IL-17 and lower IL-2, respectively). The presence of the most severe MF, psychomotor retardation, was associated with a higher pro-inflammatory response (higher IL-6).

Psychiatric face of COVID-19

The Coronavirus Disease 2019 (COVID-19) represents a severe multiorgan pathology which, besides cardio-respiratory manifestations, affects the function of the central nervous system (CNS). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), similarly to other coronaviruses demonstrate neurotropism; the viral infection of the brain stem may complicate the course of the disease through damaging central cardio-respiratory control. The systemic inflammation as well as neuroinflammatory changes are associated with massive increase of the brain pro-inflammatory molecules, neuroglial reactivity, altered neurochemical landscape and pathological remodelling of neuronal networks. These organic changes, emerging in concert with environmental stress caused by experiences of intensive therapy wards, pandemic fears and social restrictions, promote neuropsychiatric pathologies including major depressive disorder, bipolar disorder (BD), various psychoses, obsessive-compulsive disorder and post-traumatic stress disorder. The neuropsychiatric sequelae of COVID-19 represent serious clinical challenge that has to be considered for future complex therapies.

[Depression and severity of articular destruction in patients with rheumatoid arthritis]

AIM

To assess the influence of anxiety and depressive disorders on joint destruction in patients with rheumatoid arthritis (RA).

MATERIALS AND METHODS

128 RA-patients were included, 87% were women with a mean age of 47.411.3 years and a median of RA duration 96 [48; 228] months. At the inclusion most patients had moderate (n=56, 43.7%) and severe (n=48, 37.5%) disease activity according to DAS28. Joint destruction was classified as maximal in patients with radiographic stage III, IV and/or osteonecrosis) and minimal in patients with stage I, II and no osteonecrosis. Pain intensity was measured with the BPI (Brief Pain Inventory) scale, severity of fatigue with fatigue severity scale (FSS), clinically important fatigue was diagnosed in patients with FSS4. Anxiety and depressive disorders (ADD) were diagnosed by a licensed psychiatrist in 123 (96.1%) of RA-patients in accordance with ICD-10 in semi-structured interview. Severity of depression and anxiety was evaluated with Montgomery-Asberg Depression Rating Scale (MADRS) and Hamilton Anxiety Rating Scale (HAM-A). RA-patients with ADD were divided into the following treatment groups: 1 сDMARDs (n=39), 2 сDMARDs+PPT (sertraline or mianserine), n=43, 3 сDMARDs+bDMARDs (n=32), 4 сDMARDs+bDMARDs+PPT (sertraline or mianserine), n=9. Biologics treatment duration varied from 1 to 6 years, antidepressants from 6 to 96 weeks. 83 (67.5%) RA patients were assessed at five-years follow-up. Linear regression analysis was conducted to determine factors associated with maximal join destruction.

RESULTS

According to linear regression analysis, maximal joint destruction at 5 years follow-up was associated with higher baseline BPImax, longer RA and ADD duration, clinically important fatigue at baseline, baseline extraarticular RA manifestations, recurrent depressive disorder at 5-years follow-up and treatment with cDMARDs only.

CONCLUSION

Recurrent depressive disorder without antidepressant treatment is an important predictor of progression of joint destruction in patients with rheumatoid arthritis.

Interferon-γ acutely augments inhibition of neocortical layer 5 pyramidal neurons

BACKGROUND

Interferon-γ (IFN-γ, a type II IFN) is present in the central nervous system (CNS) under various conditions. Evidence is emerging that, in addition to its immunological role, IFN-γ modulates neuronal morphology, function, and development in several brain regions. Previously, we have shown that raising levels of IFN-β (a type I IFN) lead to increased neuronal excitability of neocortical layer 5 pyramidal neurons. Because of shared non-canonical signaling pathways of both cytokines, we hypothesized a similar neocortical role of acutely applied IFN-γ.

METHODS

We used semi-quantitative RT-PCR, immunoblotting, and immunohistochemistry to analyze neuronal expression of IFN-γ receptors and performed whole-cell patch-clamp recordings in layer 5 pyramidal neurons to investigate sub- and suprathreshold excitability, properties of hyperpolarization-activated cyclic nucleotide-gated current (I_h), and inhibitory neurotransmission under the influence of acutely applied IFN-γ.

RESULTS

We show that IFN-γ receptors are present in the membrane of rat's neocortical layer 5 pyramidal neurons. As expected from this and the putative overlap in IFN type I and II alternative signaling pathways, IFN-γ diminished I_h, mirroring the effect of type I IFNs, suggesting a likewise activation of protein kinase C (PKC). In contrast, IFN-γ did neither alter subthreshold nor suprathreshold neuronal excitability, pointing to augmented inhibitory transmission by IFN-γ. Indeed, IFN-γ increased electrically evoked inhibitory postsynaptic currents (IPSCs) on neocortical layer 5 pyramidal neurons. Furthermore, amplitudes of spontaneous IPSCs and miniature IPSCs were elevated by IFN-γ, whereas their frequency remained unchanged.

CONCLUSIONS

The expression of IFN-γ receptors on layer 5 neocortical pyramidal neurons together with the acute augmentation of inhibition in the neocortex by direct application of IFN-γ highlights an additional interaction between the CNS and immune system. Our results strengthen our understanding of the role of IFN-γ in neocortical neurotransmission and emphasize its impact beyond its immunological properties, particularly in the pathogenesis of neuropsychiatric disorders.

Peripheral cytokine levels and response to antidepressant treatment in depression: a systematic review and meta-analysis

Predicting antidepressant treatment response has been a clinical challenge for major depressive disorder (MDD). The inflammation hypothesis of depression suggests that cytokines play a key role in the pathophysiology of MDD and alterations in peripheral cytokine levels are associated with antidepressant treatment outcome. Present meta-analysis aimed to examine the association between baseline peripheral cytokine levels and the response to antidepressant treatment and to evaluate whether changes of cytokine levels were associated with the response to antidepressant treatment in patients with MDD. Human-based studies published in any language in peer-reviewed journals were systematically searched from the PubMed, Embase and Web of Science databases, from inception up to October 2018. The search terms included cytokine, depressive disorder and antidepressant and their synonyms. Case-control or case-case studies reporting on levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, CRP, TNF-α, IFN-γ, GM-CSF, MIP-1α, and Eotaxin-1 in patients with MDD based on validated depression scales both before and after antidepressant treatment were included. Of 7408 identified records, 44 studies met inclusion. Standardized mean differences in each cytokine were evaluated, and random-effects meta-analyses were performed. MDD patients who responded to antidepressant treatment had lower baseline IL-8 levels than the nonresponders (Hedge's g = -0.28; 95%CI, -0.43 to -0.13; P = 0.0003; FDR = 0.004). Antidepressant treatment significantly decreased levels of TNF-α (Hedge's g = 0.60; 95%CI, 0.26-0.94; P = 0.0006; FDR = 0.004) only in responders, and responders showed significantly more decreased TNF-α levels compared with nonresponders (P = 0.046). These findings suggested that alterations in peripheral cytokine levels were associated with antidepressant treatment outcomes in MDD. Further investigations are warranted to elucidate sources of heterogeneity and examine the potentiality of using inflammatory cytokines as novel predictive markers for the pharmacological treatment of MDD.

SOD2 genetic polymorphism (rs4880) has no impact on 6-month response to antidepressant treatment and inflammatory biomarkers in depressed patients

Two thirds of patients suffering from a major depressive episode (MDE) do not reach a complete response with antidepressant drugs. This lack of response is due to several factors, including genetic determinants. Since major depressive disorder is associated with inflammatory and oxidative stress abnormalities, the metabolism of superoxide anions might be involved in non-response to antidepressant drugs. Superoxide anions are metabolized by manganese-dependent superoxide dismutase (SOD2) in the mitochondria. A functional genetic polymorphism (SOD2, rs4880), responsible of a 40% reduction in enzyme activity, is associated with anti-inflammatory response of rosuvastatin. We investigated the association of ala-allele of SOD2 rs4880 and both antidepressant efficacy and inflammatory parameters in patients treated for a MDE with antidepressant drugs. The Hamilton Depression Rating Scale (HDRS) score and levels of plasma CRP and inflammatory cytokines were assessed at baseline, one month (M1), 3 months (M3) and 6 months (M6) after antidepressant treatment. They were compared according to SOD2 genetic polymorphism. Of the 484 patients studied, 361 (74.6%) carried the ala-allele (Ala group), 123 (25.4%) of them had Val/Val genotype (Val/Val group). No significant difference was observed between the Ala and Val/Val groups neither for baseline clinical characteristics, nor for HDRS scores, response/remission rates, plasma CRP and cytokine levels throughout the study. The rs4880 SOD2 genetic polymorphism was not associated with the clinical response and cytokines levels after antidepressant treatment. These data suggest that SOD2 is not a major genetic determinant of antidepressant response. Other genes of the oxidative stress pathways should be explored in further studies.

Inflammation and the dimensions of depression: A review

Patients with depressive disorders show a wide range of clinical manifestations including cognitive and neurovegetative symptoms. Importantly, these symptoms can differ in terms of biological etiology, and deconstructing depression into specific symptoms may provide valuable insight into the underlying neurobiology. Little research has examined inflammation in the context of depressive dimensions. Here we conduct a narrative review of the existing literature (21 studies) to elucidate whether the depression-inflammation link is symptom specific. Overall, there is evidence that an association exists between neurovegetative symptoms of depression and inflammation, independent of cognitive symptoms. The same cannot be said of cognitive symptoms and inflammation. There is also some evidence of gender differences in the directionality of the relationship between depression and inflammation. Potential explanations for these findings, limitations of the existing literature and recommendations for future research design are discussed.

Multimodal Psychotherapeutic Inpatient Therapy of Depression Is Successful in Patients With High Cytokine Production

Objective: In experimental settings, systemically elevated inflammation markers interfere with major depression treatment. In German healthcare, compulsory national health insurance covers treatment of a wide variety of depressive disorders, if it follows evidence-based medicine guidelines combining recommended therapies. To date, little is known about the relevance of immune system cytokine production with regard to real-world clinical care for patients with moderate depression. Methods: Seventy three patients with moderate depression subjected to multimodal psychotherapeutic inpatient therapy (mPT) following a psychodynamic concept at a German university hospital were included. As a primary outcome, mPT success, evidenced by delta HADS "depression," was analyzed according to tumor necrosis factor alpha (TNFα) production by peripheral blood mononuclear cells (PBMC) after phytohemagglutinin (PHA) challenge at baseline. Secondary outcomes addressed the inflammatory response and mental health comparing high and low TNFα-producers. Results: First, higher PBMC TNFα production at baseline predicted a better mPT-outcome (R ² 0.162, p = 0.014). Second, patients with high TNFα (hTNF) at baseline produced significantly more acute inflammatory cytokines [interleukin (IL)1β, IL6), TH1/TH2 cytokines [interferon gamma (IFNγ), IL4] as well as eotaxin and IL2 compared to low TNFα producers (lTNF) (Cohen's ds between -0.532 and -1.013). Demographic data, diagnosis subtype-distribution, medication, systemic inflammation markers [C-reactive protein (CRP), high mobility group box 1 (HMGB1), leptin], anxiety and depression (HADS) did not differ. From baseline to mPT-discharge, HADS "depression" decreased in both hTNF (11.31 to 5.47, p = 0.001, d = 1.184) and lTNF patients (11.50-7.92, p = 0.001, d = -0.765), while PBMC cytokine production decreased significantly in hTNF (Cohen's ds between -0.304 and -0.345) with a significant group by time interaction for TH1/TH2 ratio. At the end of therapy, comparison of TNF groups revealed significantly lower depression-scores in hTNF compared to lTNF patients (5.47 compared to 7.92, p = 0.035, d = 0.504). Conclusions: Our study demonstrates successful treatment of depression in a clinical care setting using multimodal psychotherapy based on a psychodynamic concept following guideline recommendation. The greatest improvement in patient depression was linked to the highest production of TNFα by PBMCs at baseline. Our study contributes to the definition of patient subpopulations with differing cytokine responses that are related to succesful treatment of depression.

Is There an Association or Not?-Investigating the Association of Depressiveness, Physical Activity, Body Composition and Sleep With Mediators of Inflammation

BACKGROUND

Cytokines are mediators of inflammation that contribute to a low-grade inflammation in different disorders like major depression and obesity. It still remains unclear which psychological and medical factors interact with cytokine regulation. In the current investigation, the association between levels of pro-and anti-inflammatory cytokines and anthropometrics, mood state (depressiveness), physical activity and sleep were investigated in a sample of community-dwelled adults.

METHODS

Forty-nine subjects met the inclusion criteria for analyses and were assessed at two time-points (baseline (T1) and follow-up (T2), average T1-T2-interval = 215 days). Serum cytokine measures included the pro-inflammatory cytokines interleukin (IL)-2, IL-12, IFN-γ and TNF-α, the anti-inflammatory cytokines IL-4, IL-5, IL-10 and IL-13 and the granulocyte-macrophage colony-stimulating factor (GM-CSF); anthropometrics were assessed via physical examination, depressiveness was assessed via Beck Depression Inventory (BDI)2, parameters of physical activity (steps, METs) and sleep (night/total sleep duration) were measured via a 1-week actigraphy.

RESULTS

Correlation analyses showed low-to moderate significant relationships between the majority of cytokines and the BDI2 at T1, positive correlation with weight and BMI at T1 and T2, and negative correlations with the number of steps and METs at T2 and T2. Regression analyses for T1 revealed that the BDI2 score was the best positive predictor for the concentrations of all nine cytokines, followed by the number of steps and the nightsleep duration as negative predictors. At T2, the amount of steps was found to be negatively associated with IL-4, IL5, IL-10, GM-CSF, IFN-γ, and TNF-α, whereas the BMI could significantly predict IL-12 and IL-13. The BDI2-score was not significantly associated with any of the cytokines. No associations could be found between dynamics in cytokines from T1 and T2 and changes in any of the variables.

DISCUSSION

The present results indicate an influence of physical activity, subjective well-being and body composition on inflammatory mediators. Since there was no standardized intervention targeting the independent variables between T1 and T2, no assumptions on causality can be drawn from the association results.

Ligands and receptors of the TNF superfamily are decreased in major depression and during early antidepressant therapy

BACKGROUND

The up-regulation of pro-inflammatory agents, amongst them tumor necrosis factor (TNF), may represent low-grade inflammation in major depression. To further elucidate inflammatory mechanisms related to TNF in depression, the aim of the current study was to investigate the involvement of ligands and receptors of the TNF/TNF-receptor-superfamily yet un- or little explored in major depression.

METHODS

Serum levels of ligands (TNF, TNF-related weak inducer of apoptosis [TWEAK], B-cell activating factor [BAFF], tumor necrosis factor superfamily member 14 [TNFSF14; LIGHT], A proliferation-inducing ligand [APRIL]) and receptor molecules (TNF receptor superfamily member 8 [TNFRSF8; sCD30], soluble TNF receptor type 1 [sTNFR1] and type 2 [sTNFR2]) of the TNF/TNF-receptor-superfamily were measured in 50 unmedicated patients suffering from major depression and 48 healthy controls and were reassessed in 37 of the depressed patients two weeks after the initiation of antidepressive treatment.

RESULTS

In comparison to the healthy controls, the interrelated serum levels of TWEAK, BAFF, TNFSF8, sTNFR1 and sTNFR2 were reduced both in the unmedicated and medicated depressed patients. Serum levels of BAFF and TNF significantly increased during the initiation of antidepressive treatment. In the combined sample of unmedicated depressed and healthy controls, but not the separate groups, scores of the BDI-II inversely correlated with levels of TWEAK, BAFF, sTNFR1, sTNFR2 and TNFSF8.

CONCLUSION

The current findings give evidence for a role of the TNF/TNF-receptor-superfamily in the pathophysiology of major depression that may involve reduced tissue regeneration and neurogenesis rather than an acceleration of pro-inflammatory pathways.

Cytokines in agitated and non-agitated patients admitted to an acute psychiatric department: A cross-sectional study

BACKGROUND

Different psychiatric diagnostic groups have been reported to have cytokine levels deviating from healthy controls. In acute clinical settings however, the specific challenging symptoms and signs are more important than a diagnostic group. Thus, exploration of cytokines and immune activity and their role in specific symptoms is important. Reports in this field so far are sparse.

OBJECTIVE

In the present study, we aimed to examine the association between immune activity measured as levels of cytokines and agitation (independent of diagnostic group) in patients admitted to an acute psychiatric inpatient department.

METHODS

A total of 316 patients admitted to an acute psychiatric inpatient department were included. Thirty-nine patients with psychosis were subject to subgroup analyses. Agitation was assessed by the Positive and Negative Syndrome Scale, Excitement Component (PANSS-EC). Based on PANNS-EC patients were stratified into two groups: 67 agitated patients and 249 non-agitated patients. Serum concentrations of the following immune markers were measured: interleukin (IL) -1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF) -α, interferon (IFN) -γ and transforming growth factor (TGF) -β.

RESULTS

Serum levels of TNF-α were significantly higher in patients with agitation compared to those without, both when all patients were included in the analyses (p = 0.004) and in the psychosis group (p = 0.027). After correcting for multiple testing, only the findings in the total population remained significant.

CONCLUSIONS

Our findings suggest an association between TNF-α and agitation in an acute psychiatric population. A similar trend was reproduced to the psychosis subgroup. This suggests that agitation might be an independent entity associated with cytokines across different diagnostic groups.

Lipopolysaccharide-stimulated intracellular cytokines and depressive symptoms in community-dwelling older adults

Background

Inflammation is involved in the pathophysiology of depression, and circulating inflammatory cytokines have been associated with depressive symptoms. However, measuring circulating cytokines have inherent methodological limitations. In vitro lipopolysaccharide (LPS)-stimulated intracellular cytokines (ICCs) overcome these limitations. Furthermore, because psychosocial and physiological stressors activate inflammatory responses and LPS-stimulated ICCs reflect the inflammatory responsivity of monocytes to such stressors, ICCs may reflect individual stress responsivity.

Methods

This cross-sectional study examined whether LPS-stimulated expression of ICCs in peripheral blood mononuclear cells (PBMCs) is a sensitive inflammation measure correlated with depressive symptoms in 180 community-dwelling older adults. We tested correlations of not only intracellular but also circulating inflammatory markers with depressive symptoms assessed using the 10-item Center for Epidemiological Studies Depression Scale (CES-D). Intracellular markers included expression of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and both in PBMCs. Circulating markers included IL-6, TNF-α, and C-reactive protein (CRP) in plasma.

Results

None of the correlations were statistically significant. However, in contrast to circulating markers, the correlations of ICCs were consistently in the expected direction, i.e., higher ICC expression correlating with higher depression severity.

Discussion

Despite the non-significant findings, further research is required for the evaluation of LPS-stimulated ICC expression as biomarkers of depressive symptoms.

Biomarkers for response in major depression: comparing paroxetine and venlafaxine from two randomised placebo-controlled clinical studies

The identification of biomarkers of response might speed drug development and set the premises to assist clinical practice in psychiatry. In this work, we evaluated a panel of peripheral biomarkers (including IL-6, IL-10, TNF-α, TNFRII, BDNF, CRP, MMP9 and PAI1) in depressed patients receiving paroxetine, venlafaxine, or placebo. Samples were obtained from two randomised placebo-controlled studies evaluating the efficacy and tolerability of a novel drug candidate, using either paroxetine or venlafaxine as active comparators. In both studies, the biomarker candidates were analysed in plasma collected at randomization and after 10 weeks of treatment with either placebo or active comparator (for a total of 106 and 108 subjects in the paroxetine and venlafaxine study, respectively). Data were obtained by multiplexing sandwich-ELISA system. Data were subjected to statistical analysis to assess their correlation with baseline severity and with response outcome. Increases in biomarker levels were correlated with reduction in depression severity for TNF-α, IL-6 IL-10 and CRP. Response to paroxetine treatment correlated with baseline IL-10, IL-6 and TNF-α levels, with the strongest signal being observed in males. In the venlafaxine study, a correlation was observed only between CRP level at randomisation and response, suggesting differences between the two active treatments and the two studies. Our investigations suggest that a combination of pro- and anti-inflammatory cytokines may predict response outcome in patients treated with paroxetine. The potential for IL-10, IL-6 and TNF-α as response biomarkers for a wider range of antidepressants warrants further investigations in clinical trials with other monoamine reuptake inhibitors.

Characteristics of pro- and anti-inflammatory cytokines alteration in PTSD patients exposed to a deadly earthquake

BACKGROUND

Many studies have shown that the disturbance of pro-inflammatory and/or anti-inflammatory cytokines is involved in the modulation of traumatic stress and related psychiatric disorders, typically posttraumatic stress disorder (PTSD). However, the specific immune alterations associated with PTSD symptoms are still unclear. The present study compared levels of pro- and anti-inflammatory cytokines between PTSD and non-PTSD controls, and investigated the relationships of immune changes with PTSD symptomatology.

METHODS

In this study, 51 earthquake-exposed PTSD patients and 136 earthquake-exposed healthy controls were recruited. We assessed trauma exposure, PTSD and depression severity, and quantified a panel of pro- inflammatory cytokines, including interleukin (IL)-1β, IL-2, IL-6, IL-8, tumor necrosis factor alpha (TNF-α), interferon ϒ (IFN_ϒ), and anti-inflammatory cytokines, including IL-4, IL-10 and IL-13 with enzyme-linked immunosorbent assays. Additionally, total pro-inflammatory cytokines score and total anti-inflammatory cytokines score were calculated to reflect the status of two balance system.

RESULTS

Behavioral data showed that the PTSD group had greater severity of depression, as well as total symptoms and every symptom cluster in the seven-factor model of PTSD compared to the non-PTSD control group. Immune data showed that PTSD subjects had higher levels of IL-1β and TNFα, as well as total pro-inflammatory cytokine scores compared to controls, suggesting an increase of inflammatory activity in PTSD. In all subjects, the IL-1β levels were correlated with PCL scores, after controlling for covariates, including age, education, marital status and gender, trauma exposure severity and depression.

LIMITATIONS

The current study did not include a non-traumatized healthy control group, and PTSD was assessed using a self-reported measure.

CONCLUSIONS

Thus, by including a control group comprised entirely of earthquake-exposed individuals as means to discriminate specific alterations of cytokine levels in PTSD, these findings suggest that the increased inflammatory cytokines, especially IL-1β, may play a role in the pathophysiology of PTSD.

Inflammatory Profiles in Depressed Adolescents Treated with Fluoxetine: An 8-Week Follow-up Open Study

Changes in cytokine levels in major depression and during treatment have been reported in adults. However, few studies have examined cytokine levels in an adolescent sample despite this being a common age of onset. Methods. We measured proinflammatory (IL-2, IFN-γ, IL-1β, TNF-α, IL-6, IL-12, and IL-15) and anti-inflammatory (IL-4, IL-5, IL-13, IL-1Ra, and IL-10) cytokine serum levels in 22 adolescents with major depression and 18 healthy volunteers. Cytokines were measured by multiplex bead-based immunoassays at baseline, and 4 and 8 weeks after commencement of fluoxetine administration in the clinical group. Results. Compared to healthy volunteers, adolescents with major depression at baseline showed significant increases in all pro- and anti-inflammatory cytokines, except IL-1Ra and IL-10. Significant changes were observed in fluoxetine treatment compared to baseline: proinflammatory cytokines IFN-γ, IL-1β, TNF-α, IL-6, IL-12, and IL-15 were decreased only at week 4 whereas IL-2 was increased only at week 8; anti-inflammatory cytokines IL-4 and IL-5 were increased at week 8 while IL-1Ra was reduced only at week 4. There were no significant correlations between cytokine levels and symptomatic improvement in HDRS. Discussion. The results suggest a significant interplay between cytokine levels, the depressive state, and the stage of treatment with an SSRI. To the best of our knowledge, this is the first report in depressed adolescents with elevated IL-12, IL-13, and IL-15 levels. Further studies are necessary to clarify the role and mechanisms of altered cytokine levels in the pathogenesis and physiopathology of major depressive disorder.

Hippocampal CA1 βCaMKII mediates neuroinflammatory responses via COX-2/PGE2 signaling pathways in depression

Background

Neuroinflammation has recently emerged as a critical risk factor in the pathophysiology of depression. However, the underlying molecular mechanisms and the development of novel therapeutic strategies as means to target these inflammatory pathways for use in the treatment of depression remain unresolved. In the present study, we aimed to investigate the molecular events of neuroinflammation as related to its induction of depression-like behaviors.

Methods

Chronic unpredictable mild stress (CUMS) or lipopolysaccharide (LPS) was used to induce depression-like behaviors in rats. The inflammatory factors and related proteins were verified by RT-PCR, immunoblotting, and immunofluorescence assay. In vivo intracerebral injection of adenovirus-associated virus (AAV) in rats was used to overexpress or block the function of the β form of the calcium/calmodulin-dependent protein kinase type II (βCaMKII). In vivo intracerebroventricular injection of SB203580 was used to block p38 mitogen-activated protein kinase (MAPK). Finally, the prostaglandin E2 (PGE2) concentration was verified by using enzyme-linked assay kit.

Results

The expression of cyclo-oxygenase (COX)-2, which is responsible for production of the pro-inflammatory factor PGE2 and thus glial activation, was increased in the CA1 hippocampus in a rat model of depression. Further, the βCaMKII in CA1 was significantly upregulated in depressed rats, while antidepressant treatment downregulated this kinase. Overexpression of βCaMKII via infusion of a constructed AAV-βCaMKII into the CA1 region resulted in phosphorylation of the p38 MAPK and the activating transcription factor 2 (ATF2). These effects were accompanied by an enhanced activity of the COX-2/PGE2 pathway and effectively induced core symptoms of depression. Conversely, knockdown of βCaMKII within the CA1 region reversed these inflammation-related biochemical parameters and significantly rescued depression symptoms.

Conclusion

These results demonstrate that βCaMKII can act as a critical regulator in depression via activating neuroinflammatory pathways within the CA1 region. Moreover, this study provides new perspectives on molecular targets and drug therapies for future investigation in the treatment of depression.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1377-0) contains supplementary material, which is available to authorized users.

Innate immune activation of astrocytes impairs neurodevelopment via upregulation of follistatin-like 1 and interferon-induced transmembrane protein 3

BACKGROUND

Polyriboinosinic-polyribocytidylic acid (polyI:C) triggers a strong innate immune response that mimics immune activation by viral infections. Induction of interferon-induced transmembrane protein 3 (Ifitm3) in astrocytes has a crucial role in polyI:C-induced neurodevelopmental abnormalities. Through a quantitative proteomic screen, we previously identified candidate astroglial factors, such as matrix metalloproteinase-3 (Mmp3) and follistatin-like 1 (Fstl1), in polyl:C-induced neurodevelopmental impairment. Here, we characterized the Ifitm3-dependent inflammatory processes focusing on astrocyte-derived Fstl1 following polyI:C treatment to assess the neuropathologic role of Fstl1.

METHODS

Astrocytes were treated with PBS (control) or polyI:C (10 μg/mL). The conditioned medium was collected 24 h after the polyI:C treatment and used as astrocyte condition medium (ACM). The expression of Fstl1 mRNA and extracellular Fstl1 protein levels were analyzed by quantitative PCR and western blotting, respectively. For functional studies, neurons were treated with ACM and the effects of ACM on dendritic elongation were assayed. To examine the role of Fstl1, recombinant Fstl1 protein and siRNA for Fstl1 were used. To investigate the expression of Fstl1 in vivo, neonatal mice were treated with vehicle or polyI:C on postnatal day 2 to 6.

RESULTS

ACM prepared with polyI:C (polyI:C ACM) contained significantly higher Fstl1 protein than control ACM, but no increase in Fstl1 was observed in polyI:C ACM derived from Ifitm3-deficient astrocytes. We found that the production of Fstl1 involves the inflammatory responsive molecule Ifitm3 in astrocytes and influences neuronal differentiation. In agreement, the levels of Fstl1 increased in the hippocampus of polyI:C-treated neonatal mice. COS7 cells co-transfected with both Fstl1 and Ifitm3 had higher extracellular levels of Fstl1 than the cells transfected with Fstl1 alone. Treatment of primary cultured hippocampal neurons with recombinant Fstl1 impaired dendritic elongation, and the deleterious effect of polyI:C ACM on dendritic elongation was attenuated by knockdown of Fstl1 in astrocytes.

CONCLUSIONS

The extracellular level of Fstl1 is regulated by Ifitm3 in astrocytes, which could be involved in polyI:C-induced neurodevelopmental impairment.

Medial Forebrain Bundle Deep Brain Stimulation Reverses Anhedonic-Like Behavior in a Chronic Model of Depression: Importance of BDNF and Inflammatory Cytokines

Deep brain stimulation (DBS) of the medial forebrain bundle (MFB) displays a promising antidepressant effects in patients with treatment-refractory depression; however, a clear consensus on underlying mechanisms is still enigmatic. Herein, we investigated the effects of MFB-DBS on anhedonic-like behavior using the Froot Loops® consumption in a chronic unpredictable mild stress (CUS) model of depression, biochemical estimation of peripheral and central inflammatory cytokines, stress hormone, and brain-derived neurotrophic factor (BDNF). Seven days of MFB-DBS significantly reversed the 42-day CUS-generated anhedonic-like phenotype (p < 0.02) indicated by an increase in Froot Loops® consumption. Gross locomotor activity and body weight remained unaffected across the different groups. A dramatic augmentation of adrenocorticotropic hormone levels was seen in the plasma and cerebrospinal fluid (CSF) samples of CUS rats, which significantly reduced following MFB-DBS treatment. However, C-reactive protein levels were found to be unaffected. Interestingly, decreased levels of BDNF in the CUS animals were augmented in the plasma, CSF, and hippocampus following MFB-DBS, but remained unaltered in the nucleus accumbens (NAc). While multiplex assay revealed no change in the neuronal levels of inflammatory cytokines including IL-1α, IL-4, IL-10, IL-12, IL-13, and IL-17 in the neuroanatomical framework of the hippocampus and NAc, increased levels of IL-1β, IL-2, IL-5, IL-6, IL-7, IL-18, TNF-α, and INF-γ were seen in these brain structures after CUS and were differentially modulated in the presence of MFB stimulation. Here, we show that there is dysregulation of BDNF and neuroimmune mediators in a stress-driven chronic depression model, and that chronic MFB-DBS has the potential to undo these aberrations.

Second generation atypical antipsychotics olanzapine and aripiprazole reduce expression and secretion of inflammatory cytokines in human immune cells

Schizophrenia and major depression are associated with alterations in peripheral inflammatory markers, and anti-inflammatory therapy has been proposed as a promising add-on approach in the pharmacologic treatment of both disorders. Second-generation atypical antipsychotics are currently first-line drugs in the treatment of schizophrenia and are also used as augmentation strategies in treatment-resistant major depression. Furthermore, these drugs have been reported to exhibit distinct metabolic side effects and to influence inflammatory processes. In this study, we used ex vivo stimulation of primary human peripheral blood mononuclear cells (PBMC) from healthy blood donors with atypical antipsychotics olanzapine or aripiprazole to examine effects on cytokine production independent from metabolic side effects and disease status. Both olanzapine and aripiprazole stimulation decreased mRNA levels of IL-1β, IL-6, and TNF-α and resulted in diminished protein concentrations of IL-6 and TNF-α in conditioned medium of stimulated PBMC. A multiplex approach revealed additional downregulation of IL-2; MIP-1β and IP-10 secretion. Similarly, olanzapine and aripiprazole stimulation of the human monocytic cell line THP-1 resulted in a significant decrease in expression and secretion of IL-1β and TNF-α. Our results suggest that atypical antipsychotics directly influence immune cell function and thereby highlight the importance to factor in potential side effects of drugs routinely used in treatment of schizophrenia and major depression on inflammatory processes when considering anti-inflammatory drug therapy as an additional treatment option.

Type A Behavior Pattern, Impulsiveness, Risk Propensity, and Empathy as Predictors of Dyspnea and Number of Infections in Men with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

BACKGROUND Stress and psychological factors can induce dyspnea in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to assess selected elements of the clinical presentation of COPD in the context of the severity of type A pattern of behavior, impulsiveness, and tendency for empathy. MATERIAL AND METHODS This was a cross-sectional study. The study group consisted of 179 men with COPD and the control group consisted of 31 healthy male smokers. In all patients, the number of infectious exacerbations over the past year, the result on the dyspnea scale (MRC), and the FEV1-to- predicted FEV1 ratio was assessed. The A pattern of behavior was measured using the Type A scale. To measure impulsivity, risk propensity, and empathy, the IVE impulsivity questionnaire was used. RESULTS An increase in the number of infectious exacerbations was associated with an increased score on the Type A scale, an increase in risk propensity, and a decrease in impulsivity score. Increased severity of dyspnea was associated with an increase in Type A behavior pattern score and an increase in the risk propensity score. CONCLUSIONS Type A behavior pattern and risk propensity are independent predictors of the number of infections in the last year and of the subjective severity of dyspnea among men with COPD and healthy male smokers.

Correlation between interferon γ and interleukin 6 with PTSD and resilience

Posttraumatic Stress Disorder (PTSD) is a debilitating psychiatric disorder with decreased general health prognosis and increased mortality. Inflammation has been hypothesised to be a link between PTSD and the most common co-morbid medical disorders. However, the relationship between inflammation and PTSD is not clear. Individual inflammatory markers have shown variable associations with PTSD. This study investigates the correlations between serum cytokines, PTSD and resilience in a cohort of Caucasian Vietnam combat veterans (n = 299). After correction for multiple testing, PTSD severity was correlated with small but significant decreases in interleukin 6 and interferon γ (p = 0.004, p = 0.013, respectively) whereas resilience was correlated with increased levels of interleukin 6 and interferon γ (p = 0.023; p = 0.007, respectively). Analyses of sub-symptoms of PTSD revealed that mood and arousal symptoms showed the most significant effect on interleukin 6 and interferon γ. More research is needed to further elucidate the mechanisms underlying the relationship between cytokine levels, PTSD sub-symptoms and trauma outcomes to improve the knowledge base of differences in trauma response and the biological system.

Effect of antidepressant treatment on peripheral inflammation markers - A meta-analysis

INTRODUCTION

Major Depressive Disorder (MDD) in accordance to the inflammatory concept is associated with complex immunological disturbances in the central nervous system (CNS). This is reflected by elevated plasma levels of inflammatory cytokines in depressed subjects. Although numerous studies report significant influence of antidepressants on pro-inflammatory/anti-inflammatory cytokines balance, the available data is often inconsistent regarding specific cytokines and drugs used. We aimed to perform a comprehensive meta-analysis of the effect of antidepressant treatment on a wide array of cytokines.

METHODS

We performed a systematic search of 6 databases, which yielded 32 studies measuring the levels of selected cytokines before and at a second time-point during antidepressant treatment. For meta-analysis of selected studies with a continuous measure we analysed variables containing the number of cases, mean and standard deviation of the level of IL-1ß, IL-2, IL-5, IL-6, IL-8, IL-10, CRP, TNF-α, IFN-γ levels observed in the different studies, in the intervention groups before and after antidepressant treatment.

RESULTS

Statistical analysis revealed significant decreases of IL-4, IL-6, and IL-10 in MDD subjects after antidepressant treatment. In case of IL-1ß the decrease was significant exclusively for SSRI drugs. We did not find any significant effect of antidepressant medication on IL-2, TNF-α IFN-γ and CRP.

CONCLUSIONS

Antidepressant treatment affects the levels of cytokines in depression. The immunological imbalance in MDD is complex and seems to be mediated by other factors yet to be elucidated. The credibility of our results is limited by high heterogeneity among studies and very few studies with a placebo-controlled design. Research with MDD subtypes, response to treatment status and cytokine associations with the kynurenine pathway taken into account pose a promising target for future studies.

Cytokine serum levels remain unchanged during lithium augmentation of antidepressants in major depression

Lithium augmentation (LA) of antidepressants is a first-line therapy in treatment-resistant depression. Immunomodulatory effects of lithium have been described. The cytokine hypothesis of depression postulates that cytokines play a key role in the pathophysiology of depression. Concordantly, it has been shown that proinflammatory cytokine serum levels decrease during antidepressant treatment. The aim of this study was to investigate changes in cytokine serum levels during LA. Serum concentrations of the cytokines interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor alpha, interferon-gamma, granulocyte and monocyte colony stimulating factor were measured in a total of 95 acutely depressed patients before and after four weeks of LA. Changes in cytokine levels were corrected for the confounding factors severity of depression, treatment response, lithium serum level, gender, age and body mass index in a linear mixed-model analysis. We did not find a significant change in any of the measured cytokine serum levels during LA (p > 0.05). In conclusion, our study does not support the role of cytokine serum levels as a state marker in treatment of depression with LA.

Serum Markers of Inflammation Mediate the Positive Association Between Neuroticism and Depression

Background: The personality trait neuroticism has been implicated in a poor response to stress, may relate to increased concentrations of cytokines and the development of depression. Inflammatory mechanisms may also be associated with the onset, severity and symptoms of depression. Both are related to poor antidepressant treatment outcome. Therefore, mediators of inflammation may bridge the relationship between neuroticism and depression. Methods: To disentangle these interrelationships, the associations between neuroticism (according to NEO-PIR-N), depressive symptoms (BDI-II scores) and serum levels of hsCRP, TNF-α, IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, GM-CSF were investigated in a group of 212 participants, consisting of 37 depressed and 175 non-depressed subjects. A mediation model was used to investigate whether the impact of neuroticism on depressive symptoms may be mediated by cytokines. Results: Regression analyses revealed that IFN-γ, IL-5, and IL-12-levels, but none of the anti-inflammatory cytokines, were associated with the overall neuroticism score and several of the cytokines were related to the different facets of neuroticism. TNF-α, IFN-γ, IL-5, IL-12, and IL-13 were further related to the severity of depressive symptoms, as well as the somatic-affective and the cognitive dimensions of depression. Pro-inflammatory IFN-γ, IL-5 and IL-12 were identified as mediators of the positive prediction of depression severity by the degree of neuroticism. Conclusions: The current findings demonstrate that conditions related to long-term stress, such as depression and high neuroticism, are related to an up-regulation of inflammatory agents. Neuroticism may increase stress perception and, thus, increase the production of pro-inflammatory messenger molecules which are involved in the development of depression. This evidence may contribute to future anti-inflammatory interventions, particularly in subjects with high neuroticism who are at risk for developing depression. Furthermore, depressed patients with high neuroticism and cytokine levels may require early escalations in the intensity of treatment, along with additional therapeutic elements to increase the rate of treatment success.

Proteomics profiling reveals inflammatory biomarkers of antidepressant treatment response: Findings from the CO-MED trial

Animal and human studies suggest an association between depression and aberrant immune response. Further, common inflammatory markers may change during the course of antidepressant treatment in patients. The objective of this study was to evaluate changes in inflammatory markers and clinical outcomes from subjects enrolled in the Combining Medications to Enhance Depression Outcome (CO-MED) trial. At baseline and week 12 (treatment completion), plasma samples of 102 participants were analyzed via a multiplex assay comprised of inflammatory markers using a 27-plex standard assay panel plus a 4-plex human acute phase xMAP technology based platform. We carried out analyses in two steps. First, t-tests were used to identify inflammatory marker levels that changed between baseline and week 12. For markers that were altered, logistic regression models were then conducted to look for associated changes in remission at week 12. Among the 31 inflammatory markers analyzed, several cytokines (IL-5, IFN-γ, IL-13), two chemokines (Eotaxin-1/CCL11, RANTES) and an acute-phase reactant (serum amyloid P component) showed change from baseline to week 12. However, only two indicated differential remission responses. Interestingly, increased levels of Eotaxin-1/CCL11 correlated with remission at week 12, whereas decreased levels of IFN-γ correlated with non-remission at week 12. Results suggest that these inflammatory proteins may serve as predictors of treatment response.

The effects of vitamin B on the immune/cytokine network and their involvement in depression

Increasing evidence indicates that there are various interactions between the nervous system and the immune system, and that the immune system plays an important role in the pathogenesis of depression. Pro-inflammatory cytokines (such as IL-1, IL-6, TNF-α) have been implicated in the neurobiological manifestations of depression. The immune/cytokine network has a powerful influence on the brain. In addition, deficiency in B vitamins has been linked to depression. Hence, greater knowledge of how immune cells change in the presence of vitamin B derivatives could improve understanding of how immune changes may correlate with depression, all of which are discussed herein.