Evaluation of interleukin-6 and serotonin as biomarkers to predict response to fluoxetine

Peripheral serotonin levels as a predictor of antidepressant treatment response: A systematic review

There are currently no reliable biomarkers to predict clinical response to pharmacological treatments of depressive disorders. Peripheral blood 5-hydroxytryptamine (5-HT; serotonin) has been suggested as a biomarker of antidepressant treatment response, but there has not been an attempt to systematically summarize and evaluate the scientific evidence of this hypothesis. In this systematic review we searched MEDLINE, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials. Twenty-six relevant studies investigating peripheral 5-HT as an antidepressant biomarker were identified. In all, we did not find robust support for an association between baseline 5-HT and treatment response. Several larger studies with lower risk of bias, however, showed that higher baseline 5-HT was associated with a greater antidepressant response to SSRIs, prompting future studies to investigate this hypothesis. Our results also confirm previous reports that SSRI treatment is associated with a decrease in peripheral 5-HT levels; however, we were not able to confirm that larger decreases of 5-HT are associated with better treatment outcome as results were inconclusive.

Inflammatory markers in persons with clinically-significant depression, anxiety or PTSD: A systematic review and meta-analysis

BACKGROUND

Depression, anxiety and PTSD appear to be risk factors for dementia, but it is unclear whether they are causal or prodromal. The inflammatory-mediated neurodegeneration hypothesis suggests a causal link, proposing that mental illness is associated with an inflammatory response which, in turn, triggers neurodegenerative changes that lead to dementia. Existing meta-analyses have yet to examine inflammatory markers in depression, anxiety or PTSD with the view to exploring the inflammatory-mediated neurodegeneration hypothesis. The current meta-analysis therefore examined whether: a) depression, anxiety and PTSD are individually associated with inflammation, independently of comorbid mental illnesses and physical health problems with known inflammatory responses, and b) there are any similarities in the inflammatory profiles of these disorders in order to provide a basis for exploring inflammation in people with dementia who have a history of clinically-significant anxiety, depression or PTSD.

METHODS

PubMed, EMBASE, PsycINFO and CINAHL searches identified 64 eligible studies.

RESULTS

Depression is associated with an inflammatory response, with tentative evidence to suggest anxiety and PTSD are also associated with inflammation. However, the specific response may differ across these disorders.

LIMITATIONS

The data for anxiety, PTSD and multiple inflammatory markers were limited.

CONCLUSIONS

Depression, anxiety, and PTSD each appear to be associated with an inflammatory response in persons who do not have comorbid mental or physical health problems that are known to be associated with inflammation. Whether this inflammatory response underlies the increased risk of dementia in persons with a history of depression and anxiety, and possibly PTSD, remains to be determined.

Age-specific associations between inflammatory markers and remission of depression during antidepressant use

The roles of inflammatory markers in predicting the response to antidepressants are controversial. The levels of inflammatory markers increase with age. Here, we compared the associations of inflammatory markers with remission during 12-week pharmacotherapy according to patient age. Higher high-sensitivity C-reactive protein (hsCRP) levels were associated with non-remission in younger, but not older, patients. However, higher interleukin (IL)-1β and IL-6 levels were associated with non-remission in all patients, regardless of age. Differential associations were observed between inflammatory markers and remission, according to patient age. Patient age should be considered when predicting the response to antidepressants based on serum hsCRP level.

Fluoxetine modulates the pro-inflammatory process of IL-6, IL-1β and TNF-α levels in individuals with depression: a systematic review and meta-analysis

Clinical evidence suggests that inflammation is a key factor to understand the causes of depressive symptoms. Fluoxetine is one of the main first-line medications used for depression, and it is hypothesized that it participates in the decrease of pro-inflammatory cytokines. Hence, our aim was to perform a meta-analysis and systematic review to understand the interaction of fluoxetine in the IL-1β, IL-6 and TNF-α inflammatory process. Studies identified in PubMed and Scopus databases were used to perform a meta-analysis via the Comprehensive software. Standardized mean difference (SMD) was used as a summary statistic. The analysis included a total of 292 individuals with major depressive disorder who received fluoxetine for a period longer than 6 weeks; additionally, IL-1β, IL-6 or TNF-α levels were measured at the end of the antidepressant treatment. The findings were significant revealed decreased levels of the cytokines studied. In conclusion, the pooled data suggest that fluoxetine treatment improved depressive symptomatology by the modulation of pro-inflammatory process such as IL-1β, IL-6 or TNF-α.

Effects of forest bathing (shinrin-yoku) on serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males

BACKGROUND

We previously found that a forest bathing (shinrin-yoku) program significantly reduced the scores for depression, anxiety, anger, fatigue, and confusion and increased the score for vigor in the profile of mood states (POMS) test and showed a potential preventive effect on the depressive status in both males and females. In the present study, we investigated the effects of a forest bathing program on the level of serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males.

METHODS

Twenty healthy male subjects aged 57.3 ± 8.4 years were selected after obtaining informed consent. These subjects took day trips to a forest park, the birthplace of forest bathing in Japan named Akasawa Shizen Kyuyourin, Agematsu, Nagano Prefecture (situated in central Japan), and to an urban area of Nagano Prefecture as a control in June 2019. On both trips, they walked 2.5 km for 2 hours each in the morning and afternoon on Saturday and Sunday, respectively. Blood was sampled in the afternoon before and after each trip. Concentrations of serotonin and lactic acid in serum were measured. The POMS test and a questionnaire for subjective sleep quality were conducted before and after the trips. Ambient temperature and humidity were monitoring during the trips. The Ethics Committees of the Nippon Medical School and Nagano Prefectural Kiso Hospital approved this study.

RESULTS

The forest bathing program significantly increased level of serotonin in serum, and significantly increased the score for vigor and decreased the score for fatigue in the POMS test. The forest bathing program also improved the sleepiness on rising and feeling refreshed (recovery from fatigue) in the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA).

CONCLUSIONS

Taken together, the present study suggests that forest bathing may have potential preventive effects on depression (depressive status).

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.

Predictive values of tumor necrosis factor-α for depression treatment outcomes: effect modification by hazardous alcohol consumption

Inflammation is potentially associated with poor antidepressant treatment outcomes. Pro-inflammatory cytokines are influenced by hazardous alcohol consumption. The aim of the present study was to investigate the effects of the serum tumor necrosis factor-α (sTNF-α) level on antidepressant treatment outcomes in terms of the 12-week and 12-month remission rates and 24-month relapse rate, and to investigate the potential modifying effects of alcohol consumption on these associations in patients with depressive disorders. At baseline, sTNF-α was measured and alcohol-related data from the Alcohol Use Disorders Identification Test (AUDIT) and consumption history were collected from 1094 patients. Patients received stepwise antidepressant treatment. Remission at 12 weeks and 12 months was defined as a Hamilton Depression Rating Scale (HAMD) score ≤ 7. Relapse (HAMD score ≥ 14) was identified until 24 months for those who had initially responded (HAMD score <14) at 12 weeks. Higher sTNF-α levels were found to have significant effects on the 12-week and 12-month non-remission and 24-month relapse rates. These effects were more prominent in those with low levels of alcohol consumption (AUDIT score ≤ 8 or no current alcohol consumption); the effects were not significant in those exhibiting hazardous alcohol consumption (AUDIT score > 8 or current drinking). Significant interactions were found for the 12-month non-remission and relapse rates, although the interaction was not statistically significant for 12-week remission. In conclusion, baseline sTNF-α levels may be a useful predictor for both short- and long-term antidepressant treatment outcomes, and the consideration of alcohol consumption status may increase predictability, in particular for long-term outcomes.

Interactive effects of systemic inflammation and life stressors on treatment response of depressive disorders

Inflammation is an important contributor in the pathophysiology of depression and recent evidence suggests that systemic inflammation and life stressors have interactive roles in depression onset. The aim of the present study was to investigate the individual and interactive effects of systemic inflammation and life stressors with short- and long-term treatment responses in outpatients with depressive disorders in a naturalistic one-year prospective design. Serum high-sensitivity C-reactive protein (hsCRP) levels were measured and number of stressful life events (SLEs) during the last 3 months were ascertained from 1094 patients at baseline. These patients received initial antidepressant monotherapy, then, for patients with an insufficient response or uncomfortable side effects, next treatment with alternative strategies were administered at every 3 weeks in the acute treatment phase (3, 6, 9, and 12 weeks) and at every 3 months in the continuation treatment phase (6, 9, and 12 months). 12-week and 12-month remission was estimated, defined as a Hamilton Depression Rating Scale score of ≤ 7. In multivariable logistic regression analyses, individual effects were found only between higher baseline serum hsCRP levels (≥1.0 vs. < 1.0 mg/L) and 12-week non-remission. Significant interactive effects between higher hsCRP levels and higher number of SLEs (≥2 vs. < 2) on both 12-week and 12-month non-remission were observed. Combining serum hsCRP levels and number of SLEs might therefore be a useful predictor for short- and long-term treatment responses in patients with depressive disorders receiving pharmacotherapy.

Effects of Antidepressant Treatment on Peripheral Biomarkers in Patients with Major Depressive Disorder (MDD)

Major depressive disorder (MDD) is one of the most prevalent mental illness and a leading cause of disability worldwide. Despite a range of effective treatments, more than 30% of patients do not achieve remission as a result of conventional therapy. In these circumstances the identification of novel drug targets and pathogenic factors becomes essential for selecting more efficacious and personalized treatment. Increasing evidence has implicated the role of inflammation in the pathophysiology of depression, revealing potential new pathways and treatment options. Moreover, convergent evidence indicates that MDD is related to disturbed neurogenesis and suggests a possible role of neurotrophic factors in recovery of function in patients. Although the influence of antidepressants on inflammatory cytokines balance was widely reported in various studies, the exact correlation between drugs used and specific cytokines and neurotrophins serum levels often remains inconsistent. Available data suggest anti-inflammatory properties of selective serotonin reuptake inhibitors (SSRIs), selective serotonin and noradrenaline inhibitors (SNRIs), and tricyclic antidepressants (TCAs) as a possible additional mechanism of reduction of depressive symptoms. In this review, we outline emerging data regarding the influence of different antidepressant drugs on a wide array of peripheral biomarkers such as interleukin (IL)-1ß, IL-2, IL-5, IL-6, IL-8, IL-10, C-reactive protein (CRP), or interferon (IFN)-γ. Presented results indicate anti-inflammatory effect for selected drugs or lack of such effect. Research in this field is insufficient to define the role of inflammatory markers as a predictor of treatment response in MDD.

Analysis of cytokine levels, T regulatory cells and serotonin content in patients with depression

Alterations in peripheral serotonin concentrations and an imbalanced immune system have been reported in patients with depression. Cytokines and T regulatory (Treg) cells may play an important role in the development of depression. This study investigates the levels of cytokines and Treg cells, as well as the concentration of serotonin (5-HT) in the blood of 89 patients suffering from depression and 89 healthy participants between two acquisitions. We investigated the state of health before (T1) and after (T2) psychological and pharmacological therapy. Both cytokine (IL-6, IL-10, TNF-α, and INF-γ) and 5-HT levels in the blood were measured by enzyme-linked immunosorbent assays. The levels of CD4⁺ CD25⁺ Treg cells were determined by flow cytometric analysis. Patients with depression showed significantly higher serum levels of IL-6 and INF-γ, no altered serum levels of IL-10 and TNF-α, and decreased platelet and serum 5-HT levels compared with healthy participants at the first acquisition. In addition, the symptoms of depression and anxiety, the TNF-α level, and the amount of CD4⁺ CD25⁺ cells in the blood were decreased from the first to the second acquisition. Further, a correlation between IL-6 and platelet 5-HT has been observed in patients. An imbalance of the immune system in patients with depression and an association of the serotonergic system and cytokines were observed. These results indicate that the development of depression might be related to several interacting proteins, including cytokines and 5-HT, and the treatment affects imbalances of these factors.

Higher baseline interleukin-1β and TNF-α hamper antidepressant response in major depressive disorder

Raised pro-inflammatory immune/inflammatory setpoints, leading to an increased production of peripheral cytokines, have been associated with Major Depressive Disorder (MDD) and with failure to respond to first-line antidepressant drugs. However, the usefulness of these biomarkers in clinical psychopharmacology has been questioned because single findings did not translate into the clinical practice, where patients are prescribed treatments upon clinical need. We studied a panel of 27 inflammatory biomarkers in a sample of 108 inpatients with MDD, treated with antidepressant monotherapy for 4 weeks upon clinical need in a specialized hospital setting, and assessed the predictive effect of baseline peripheral measures of inflammation on antidepressing efficacy (response rates and time-lagged pattern of decrease of depression severity) using a machine-learning approach with elastic net penalized regression, and multivariate analyses in the context of the general linear model. When considering both categorical and continuous measures of response, baseline levels of IL-1β predicted non-response to antidepressants, with the predicted probability to respond being highly dispersed at low levels of IL-1β, and stratifying toward non-response when IL-1β is high. Significant negative effects were also detected for TNF-α, while IL-12 weakly predicted response. These findings support the usefulness of inflammatory biomarkers in the clinical psychopharmacology of depression, and add to ongoing research efforts aiming at defining reliable cutoff values to identify depressed patients in clinical settings with high inflammation, and low probability to respond.

Potential biomarkers of emotional stress induced neurodegeneration

Mental health is a matter of great significance and interest both socially and scientifically. The present review aims to provide an informative platform about the classical biomarkers available to identify and diagnose the neurodegeneration induced by emotional stress and depression. Present article provides an expert comprehensive overview of the universally accepted markers and their mechanism of action involved in emotional stress assessment and its management. This envisioned piece of work emphasize on the incorporation of clinical markers in classical psychiatry experiments will make the information more significant, reliable and universally accepted. The information summaries in the article will facilitates the researchers of clinical psychiatry, neuropharmacology and neuropsychiatry in management of depressive disorders along with the identification of possible neurodegenerative association.

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Health is an overall outcome of emotional, physiological, endocrinological and neurological factors.

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Emotional stress and depression are silent causes of neurodegeneration.

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Clinical markers play a vital role in the management of neurological health.

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Endocrine secretions play a vital role in mediation of various neurotransmission, nerves excitability and neurodegeneration.

Increased circulatory IL-6 during 8-week fluoxetine treatment is a risk factor for suicidal behaviors in youth

OBJECTIVE

Selective serotonin reuptake inhibitors (SSRIs) are commonly used to treat anxiety and/or depression in pediatric populations. However, the response rates are low (approximately 50%). Moreover, SSRI use is frequently associated with adverse events (AE). Currently there are no available biomarkers for treatment response/AE. Identification of biomarkers predicting early response and/or AE could help maximize the benefit-risk ratio for the use of SSRIs, and accelerate matching of treatments to patients. Pro-inflammatory cytokines were proposed as potential biomarkers.

METHOD

Ninety-two patients (35 boys and 57 girls) with major depressive disorder and/or anxiety disorders, aged 13.90 ± 2.41 years, were treated with fluoxetine (FLX) for 8 weeks. Plasma concentrations of TNFα, IL-6, and IL-1β were measured by enzyme linked immunosorbent assays before and after FLX treatment. Clinical response and AE were measured using several clinical scales, including the Clinical Global Impression - improvement, Children's Depression Rating Scale-Revised, the Beck Depression Inventory, the Screen for Child Anxiety Related Emotional Disorders, the Columbia suicide severity rating scale, and the Suicide Ideation Questionnaire.

RESULTS

IL-6 levels increased after treatment only in the group of children who developed FLX-associated suicidality.

CONCLUSION

An increase in IL-6 levels during treatment may be a risk factor for the emergence of FLX-associated suicidality (OR = 1.70). Further studies are necessary to clarify the role and mechanism(s) of this cytokine in the pathogenesis of this life-threatening AE.

Inflammatory markers in depression: A meta-analysis of mean differences and variability in 5,166 patients and 5,083 controls

IMPORTANCE

The magnitude and variability of cytokine alterations in depression are not clear.

OBJECTIVE

To perform an up to date meta-analysis of mean differences of immune markers in depression, and to quantify and test for evidence of heterogeneity in immune markers in depression by conducting a meta-analysis of variability to ascertain whether only a sub-group of patients with depression show evidence of inflammation.

DATA SOURCES

Studies that reported immune marker levels in peripheral blood in patients with depression and matched healthy controls in the MEDLINE database from inception to August 29th 2018 were examined.

STUDY SELECTION

Case-control studies that reported immune marker levels in peripheral blood in patients with depression and healthy controls were selected.

DATA EXTRACTION AND SYNTHESIS

Means and variances (SDs) were extracted for each measure to calculate effect sizes, which were combined using multivariate meta-analysis.

MAIN OUTCOMES AND MEASURES

Hedges g was used to quantify mean differences. Relative variability of immune marker measurements in patients compared with control groups as indexed by the coefficient of variation ratio (CVR).

RESULTS

A total of 107 studies that reported measurements from 5,166 patients with depression and 5,083 controls were included in the analyses. Levels of CRP (g = 0.71; 95%CI: 0.50-0.92; p < 0.0001); IL-3 (g = 0.60; 95%CI: 0.31-0.89; p < 0.0001); IL-6 (g = 0.61; 95%CI: 0.39-0.82; p < 0.0001); IL-12 (g = 1.18; 95%CI: 0.74-1.62; p < 0.0001); IL-18 (g = 1.97; 95%CI: 1.00-2.95; p < 0.0001); sIL-2R (g = 0.71; 95%CI: 0.44-0.98; p < 0.0001); and TNFα (g = 0.54; 95%CI: 0.32-0.76; p < 0.0001) were significantly higher in patients with depression. These findings were robust to a range of potential confounds and moderators. Mean-scaled variability, measured as CVR, was significantly lower in patients with depression for CRP (CVR = 0.85; 95%CI: 0.75-0.98; p = 0.02); IL-12 (CVR = 0.61; 95%CI: 0.46-0.80; p < 0.01); and sIL-2R (CVR = 0.85; 95%CI: 0.73-0.99; p = 0.04), while it was unchanged for IL-3, IL-6, IL-18, and TNF α.

CONCLUSIONS AND RELEVANCE

Depression is confirmed as a pro-inflammatory state. Some of the inflammatory markers elevated in depression, including CRP and IL-12, show reduced variability in patients with depression, therefore supporting greater homogeneity in terms of an inflammatory phenotype in depression. Some inflammatory marker elevations in depression do not appear due to an inflamed sub-group, but rather to a right shift of the immune marker distribution.

Inflammatory modulation of fluoxetine use in patients with depression: A systematic review and meta-analysis

There is growing evidence that there is a relationship between major depressive disorder (MDD), also simply known as "depression", and inflammatory processes. Selective serotonin inhibitors, such as fluoxetine, are used as a first-line treatment for depression, and it is hypothesized that its use can reduce levels of proinflammatory cytokines. The aim of this systematic review and meta-analysis is to enable a better understanding of how treatment with the antidepressant fluoxetine modulates inflammation, and the roles of the main cytokines in this process. Risk of bias (RoB) in the included studies was assessed using the Cochrane Risk of Bias Assessment tool for Non-randomized studies (RoBANS). In the meta-analysis, standardized mean difference (SMD) was used as a summary statistic and grouped statistics using the generic inverse variation method in RevMan 5 with random effects model. Heterogeneous changes in cytokine levels were also evaluated from the SMD forest plot of individual studies. After analysis, we observed that fluoxetine was able to decrease TNF-α levels (SMD ± 0.90, 95% CI = 0.16, 1.165, Z ± 2.40, p = 0.02), but not change IL-6 levels (SMD ± 0.37, 95% CI = 0.21, 0.95, Z ± 1.25, p = 0.21).Fluoxetine acts by modulating neuroimmunology, and not only by acting only on the independent restoration of neurotransmission and neuroinflammation pathways.

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.

Plasma levels of IL-6 in patients with untreated major depressive disorder: comparison with catecholamine metabolites

OBJECTIVE

IL-6 and catecholamines play roles in the pathophysiology of major depressive disorder (MDD).

AIM

The present study investigated associations between plasma IL-6 and plasma catecholamine metabolites in patients with MDD.

PARTICIPANTS AND METHODS

A total of 148 patients (male/female 65/83, age 49.5±12.1 years) who met the criteria for MDD based on the Diagnostic and Statistical Manual of Mental Disorders IV and 40 participants as healthy controls (HC; male/female 23/17, age 44.0±10.5 years) were enrolled in the present study. Plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were analyzed using high-performance liquid chromatography, and plasma IL-6 levels were measured using ELISA.

RESULTS

No correlations were observed among plasma IL-6 levels, MHPG levels, and HVA levels in patients with MDD. Plasma IL-6 levels in patients with MDD were significantly higher than in the HC. A positive correlation was found between plasma IL-6 levels and Hamilton Rating Scale for Depression-17 scores.

CONCLUSION

No correlations existed between plasma IL-6 levels and plasma catecholamine metabolite levels in patients with MDD, and the severity of depressive state was related to plasma IL-6 levels in MDD.

Effects of SSRIs on peripheral inflammatory markers in patients with major depressive disorder: A systematic review and meta-analysis

INTRODUCTION

Peripheral levels of inflammatory markers are elevated in major depressive disorder (MDD). Selective serotonin reuptake inhibitors (SSRIs) affect levels of inflammatory markers in patients with MDD, but studies have reported inconsistent findings. This systematic review and meta-analysis aims to investigate the effects of SSRI treatment on peripheral levels of a range of inflammatory markers in MDD patients.

METHODS

Systematic literature search (Pubmed, Web of Science, Embase, Cochrane) for studies published before November 2018. Studies were included if they used SSRI monotherapy and peripheral levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were measured before and after treatment in patients with MDD. Meta-analysis was conducted using Comprehensive Meta-analysis (version 2). Effect sizes were calculated using bias-corrected standardized mean difference (Hedges' g) between pre- and post-treatment. Sub-group analyses, meta-regression and publication bias estimates were undertaken; sensitivity analyses were performed using different estimated pre- and post-treatment correlations and after removing poor quality studies.

RESULTS

Twenty two eligible studies including 827 MDD patients were included in the meta-analysis: fifteen studies for IL-6; eleven for TNF-α; eight for IL-10; seven for IL-1β; six for IL-4; five for IL-2; and four for IFN-γ. The pooled effect estimate indicates SSRI treatment decreased levels of pro-inflammatory markers IL-6 (Hedges' g, -0.418; 95%CI, -0.663 to -0.174; I² = 89.412), TNF-α (Hedges' g, -0.554; 95%CI, -0.990 to -0.118; I² = 95.438) and IL-1β (Hedges' g = -0.574; 95%CI, -1.014 to -0.135; I² = 91.622), and anti-inflammatory marker IL-10 (Hedges' g = -0.615; 95%CI, -0.989 to -0.242; I² = 90.406). There were no significant treatment effects on levels of IL-2, IL-4, or IFN-γ. There was a high level of heterogeneity between studies. Sensitivity analyses indicated the robustness of the primary analyses.

CONCLUSIONS

The current review and meta-analysis indicates moderate immunomodulating effects of SSRI treatment for MDD, which suggests SSRIs may owe some of their therapeutic effect to their anti-inflammatory properties. High heterogeneity across studies may limit interpretation of the findings and larger randomized clinical trials are warranted.

Low-Grade Inflammation as a Predictor of Antidepressant and Anti-Inflammatory Therapy Response in MDD Patients: A Systematic Review of the Literature in Combination With an Analysis of Experimental Data Collected in the EU-MOODINFLAME Consortium

Low-grade inflammation plays a role not only in the pathogenesis of major depressive disorder (MDD) but probably also in the poor responsiveness to regular antidepressants. There are also indications that anti-inflammatory agents improve the outcomes of antidepressants. Aim: To study whether the presence of low-grade inflammation predicts the outcome of antidepressants, anti-inflammatory agents, or combinations thereof. Methods: We carried out a systematic review of the literature on the prediction capability of the serum levels of inflammatory compounds and/or the inflammatory state of circulating leukocytes for the outcome of antidepressant/anti-inflammatory treatment in MDD. We compared outcomes of the review with original data (collected in two limited trials carried out in the EU project MOODINFLAME) on the prediction capability of the inflammatory state of monocytes (as measured by inflammatory gene expression) for the outcome of venlafaxine, imipramine, or sertraline treatment, the latter with and without celecoxib added. Results: Collectively, the literature and original data showed that: 1) raised serum levels of pro-inflammatory compounds (in particular of CRP/IL-6) characterize an inflammatory form of MDD with poor responsiveness to predominately serotonergic agents, but a better responsiveness to antidepressant regimens with a) (add-on) noradrenergic, dopaminergic, or glutamatergic action or b) (add-on) anti-inflammatory agents such as infliximab, minocycline, or eicosapentaenoic acid, showing-next to anti-inflammatory-dopaminergic or lipid corrective action; 2) these successful anti-inflammatory (add-on) agents, when used in patients with low serum levels of CRP/IL-6, decreased response rates in comparison to placebo. Add-on aspirin, in contrast, improved responsiveness in such "non-inflammatory" patients; 3) patients with increased inflammatory gene expression in circulating leukocytes had a poor responsiveness to serotonergic/noradrenergic agents. Conclusions: The presence of inflammation in patients with MDD heralds a poor outcome of first-line antidepressant therapies. Immediate step-ups to dopaminergic or glutamatergic regimens or to (add-on) anti-inflammatory agents are most likely indicated. However, at present, insufficient data exist to design protocols with reliable inflammation parameter cutoff points to guide such therapies, the more since detrimental outcomes are possible of anti-inflammatory agents in "non-inflamed" patients.

Baseline Serum Levels of Beclin-1, but Not Inflammatory Factors, May Predict Antidepressant Treatment Response in Chinese Han Patients With MDD: A Preliminary Study

Currently, the choice of medical treatment for major depressive disorder (MDD) is primarily based on a trial-and-error process. Thus, identification of individual factors capable of predicting treatment response is of great clinical relevance. Recent work points towards beclin-1 and inflammatory factors as potential biomarkers of antidepressant treatment response. The primary aim of the study was to investigate whether pre-treatment serum levels of beclin-1 and inflammatory factors could predict antidepressant treatment response in Chinese Han patients with MDD. Forty patients with MDD were treated with either a selective serotonin reuptake inhibitor (SSRI) (paroxetine in 20 cases) or a serotonin-norepinephrine reuptake inhibitor (SNRI) (duloxetine in 13 cases and venlafaxine in 7 cases). Depression scores and serum levels of beclin-1 were measured at the baseline and after 8 weeks of antidepressant treatment. Serum C-reactive protein (CRP), interleukin (IL)-1B, and IL-6 levels were determined using enzyme-linked immunosorbent assay kits at the baseline. Twenty-seven patients were identified as treatment responders, whereas 13 were identified as non-responders after 8 weeks of antidepressant treatment. Baseline serum beclin-1 levels were significantly higher in non-responders than in responders (p = 0.001), whereas no differences were found in baseline serum CRP, IL-1B, or IL-6 levels between responders and non-responders. There were no significant correlations between baseline levels of beclin-1 and baseline IL-1β, IL-6, and CRP levels-neither in the total sample nor in responder and non-responder groups. Moreover, logistic regression models and a random forest model showed that baseline serum beclin-1, but not inflammatory factors, was an independent and the most important predictor for antidepressant treatment response. Furthermore, serum beclin-1 levels were significantly increased in responders (p = 0.027) but not in non-responders after 8 weeks of treatment (p = 0.221). Baseline serum beclin-1 levels may be a predictive biomarker of antidepressant response in patients with MDD. Moreover, beclin-1 may be involved in the therapeutic effect of antidepressant drugs.

Both Serum Brain-Derived Neurotrophic Factor and Interleukin-6 Levels Are Not Associated with Therapeutic Response to Lamotrigine Augmentation Therapy in Treatment-Resistant Depressive Disorder

BACKGROUND/AIMS

Serum levels of brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) were prospectively monitored in relation with therapeutic response to lamotrigine augmentation therapy in 46 (15 males and 31 females) inpatients with treatment-resistant depressive disorder during an 8-week treatment with lamotrigine using an open-study design.

METHODS

The subjects were 46 depressed patients who had already shown insufficient response to at least 3 psychotropics including antidepressants, mood stabilizers, and atypical antipsychotics. The diagnoses were major depressive disorder (n = 19), bipolar I disorder (n = 6), and bipolar II disorder (n = 22). The final doses of lamotrigine were 100 mg/day for 26 subjects who were not taking valproate and 75 mg/day for 20 subjects taking valproate, respectively. Depressive symptoms were evaluated by the Montgomery-Åsberg Depression Rating Scale (MADRS) before and after the 8-week treatment. Blood sampling was performed before the start of lamotrigine treatment and at week 8. Serum BDNF and IL-6 levels were measured using quantitative sandwich enzyme immunoassays.

RESULTS

No significant changes in serum BDNF or IL-6 levels during the 8-week lamotrigine treatment were observed in the total of subjects, responders or nonresponders. There was no significant correlation between the changes in serum BDNF or IL-6 levels and the percent improvement in MADRS scores in the overall subjects.

CONCLUSION

The present study suggests that the acute effect of lamotrigine augmentation therapy for a major depressive episode is not related to either BDNF or IL-6, at least in patients with treatment-resistant depressive disorder.

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.

Clinical Phenotype of Depression Affects Interleukin-6 Synthesis

Major depressive disorder (MDD) is not a single disease, but a number of various ailments that form one entity. Psychomotor retardation, anhedonia, sleep disorders, an increased suicide risk, and anxiety are the main symptoms that often define the clinical diagnosis of depression. Interleukin-6 (IL-6), as one of the proinflammatory cytokines, seems to be overexpressed during certain mental disorders, including MDD. Overexpression of IL-6 in depression is thought to be a factor associated with bad prognosis and worse disease course. IL-6 may directly affect brain functioning and production of neurotransmitters; moreover, its concentration is correlated with certain clinical symptoms within the wide range of depressive symptomatology. Furthermore, there is a strong correlation between IL-6 synthesis and psychosomatic functioning of the patient. This article discusses potential sources and significance of IL-6 in the pathogenesis of depression.

Is metabolic dysregulation associated with antidepressant response in depressed women in climacteric treated with individualized homeopathic medicines or fluoxetine? The HOMDEP-MENOP Study

BACKGROUND

Climacteric is associated with both depression and metabolic dysregulation. Scarce evidence suggests that metabolic dysregulation may predict poor response to conventional antidepressants. Response to depression treatment has not been studied in homeopathic medicine. The aim of this study was to investigate the prevalence of metabolic disorders in depressed climacteric women treated with homeopathic medicines, fluoxetine or placebo, and if these alterations have any association with response to depression treatment.

METHODS

One hundred and thirty-three Mexican women (40-65 years) with depression, enrolled in the HOMDEP-MENOP study, a randomized, placebo-controlled, double-blind, double-dummy, three-arm trial with a 6 week follow-up, underwent a complete medical history and clinical examination. Metabolic parameters were assessed at baseline. Association between baseline metabolic parameters and response to depression treatment was analyzed with bivariate analysis in the three groups. Odds ratios (OR) with their 95% confidence interval (95% CI) were calculated. Metabolic parameters were considered for inclusion in the logistic regression model if they had a statistically significant relationship with response rate on bivariate analysis at p<0.05 or if they were clinically relevant.

RESULTS

Overall combined prevalence (obesity and overweight) was 86.5%; 52.3% had hypertriglyceridemia; 44.7% hypercholesterolemia; 46.7% insulin resistance; and 16% subclinical hypothyroidism. There was no statistically significant association between dyslipidemia, overweight, or insulin resistance and non-response in the homeopathy group [OR (95% CI) 1.57 (0.46-5.32), p=0.467; 0.37 (0.003-1.11), p=0.059; 0.67 (0.16-2.7), p=0.579, respectively].

CONCLUSION

Metabolic dysregulation was not significantly associated with response to depression treatment in depressed climacteric women treated with individualized homeopathic treatment (IHT), fluoxetine or placebo. Due to the high prevalence of metabolic disorders and its relationship with depression in the climacteric, further investigation should be focused on whether individualized prescriptions based on classical homeopathy for depressed climacteric women have an effect on metabolic parameters, and/or if treating the metabolic disorders at the same time could lead to higher response rates. ClinicalTrials.gov Identifier: NCT01635218 URL: http://clinicaltrials.gov/ct2/show/NCT01635218?term=depression+homeopathy&rank=1.