Depression induced by treatment with interferon-alpha in patients affected by hepatitis C virus

New lung cancer treatments (immunotherapy and targeted therapies) and their associations with depression and other psychological side effects as compared to chemotherapy

OBJECTIVE

Lung cancer carries a high prevalence of distress, anxiety and depression. New treatments, targeted therapy and immunotherapy have changed the disease course for subsets of patients and confer longer survival, but their psychological associations and possible mechanisms (e.g., inflammation and physical symptoms) are not well described.

METHOD

Patients with metastatic lung cancer undergoing systemic treatment (n = 109) were evaluated for distress, self-endorsed problems using the Distress Thermometer and Problem List, and depression and anxiety using the Hospital Anxiety and Depression Scale. Demography, cancer-related information, and inflammation were evaluated for their associations with chemotherapy, targeted therapy, and immunotherapy. Inflammation was measured by C-reactive protein, albumin, and neutrophil to lymphocyte ratio.

RESULTS

Chemotherapies were given most often followed by immunotherapy and targeted therapies. Depression and anxiety were endorsed by 23.9%, respectively, and 41.1% had significant distress. Chemotherapy was associated with depression (p = .006) and inflammation (p < .001). Physical symptoms were the same among treatment types. Targeted therapy and immunotherapy predicted for less depression (p = .04, p = .04 respectively) than chemotherapy when controlling for age, sex, and performance status however these predictors where not significant when controlled for inflammation.

CONCLUSION

New immunotherapy and targeted therapies are associated with less depression and inflammation among patients who are living longer while their physical symptoms are the same.

Inflaming sex differences in mood disorders

Men and women often experience different symptoms or rates of occurrence for a variety of mood disorders. Many of the symptoms of mood disorders overlap with autoimmune disorders, which also have a higher prevalence in women. There is a growing interest in exploring the immune system to provide biomarkers for diagnosis of mood disorders, along with new targets for developing treatments. This review examines known sex differences in the immune system and their relationship to mood disorders. We focus on immune alterations associated with unipolar depression, bipolar depression, and anxiety disorders. We describe work from both basic and clinical research examining potential immune mechanisms thought to contribute to stress susceptibility and associated mood disorders. We propose that sex and age are important, intertwined factors that need to be included in future experimental designs if we are going to harness the power of the immune system to develop a new wave of treatments for mood disorders.

C-reactive protein and its association with depression in patients receiving treatment for metastatic lung cancer

BACKGROUND

Depression is highly prevalent in lung cancer. Although there is a known association between inflammation and depression, this relationship has not been examined in patients with lung cancer who undergo treatment with immune and other targeted drug therapies. Peripheral blood C-reactive protein (CRP), a marker of systemic inflammation, may help identify metastatic lung cancer patients with inflammation-associated depression.

METHOD

Patients with metastatic lung cancer undergoing treatment were evaluated for depression using the Hospital Anxiety and Depression Scale (HADS). Inflammation (CRP and CRP cutoffs ≥1 and ≥3 mg/mL) and demographic and treatment variables were analyzed for association with depression.

RESULTS

One hundred nine consecutive participants exhibited an average plasma CRP concentration of 1.79 mg/mL (median, 0.75 mg/mL [standard deviation, 2.5 mg/mL), and 20.7% had a CRP concentration of ≥3.0 mg/mL; 23.9% met depression screening criteria (HADS ≥8). A log transformation of CRP was significantly correlated with depression severity (r = 0.47, P < .001). CRP was the only covariate to predict depression severity (P = .008) in a multivariate model including lung cancer disease subtype and type of systemic treatment. Receiver operating characteristic analysis indicated that CRP had moderate predictive accuracy in identifying elevated depression (area under the curve = 0.74). A cutoff of CRP ≥3.0 generated high specificity (88%) but identified only 50% of those with elevated depression.

CONCLUSION

Elevated CRP is associated with depression in patients with metastatic lung cancer. Thus, CRP may identify a subset of lung cancer patients with inflammation-induced depression and may be useful in predicting response to treatments that target inflammation or its downstream mediators on the brain.

Expression of inflammatory markers in women with perinatal depressive symptoms

Perinatal depression affects 10-20% of women and is associated with poor outcomes for mother and child. Inflammation is associated with depression in non-pregnant adults. Perinatal depression and inflammation in pregnancy are independently associated with morbidities including obesity, gestational diabetes, preeclampsia, and preterm birth. The role of inflammation in perinatal depression has received little attention. We hypothesized an association between self-reported perinatal depressive symptoms and serum inflammatory biomarkers TNF-α, IL-6, IL-1β, and CRP. 110 healthy gravidas were recruited in third trimester from an academic medical center, with a baseline study visit at a mean of 32.5 (SD ± 1.8) weeks gestational age. Sixty-three participants completed the Edinburgh Postnatal Depression Scale (EPDS) and provided demographic information and serum samples upon enrollment and at 3 and 6 months postpartum. Serum inflammatory markers were quantified by multiplex array. Multiple linear mixed effects models were used to evaluate trends of biomarkers with the EPDS score in the third trimester of pregnancy and the postpartum period. Elevated serum TNF-α was associated with lower EPDS total score (β = - 0.90, p = 0.046) after adjusting for demographics and medication use. In contrast, IL-6, CRP, and IL-1β did not demonstrate statistically significant associations with depressive symptoms by the EPDS in either crude or adjusted models. Study findings showed no association or an inverse (TNF-α) association between inflammatory markers and perinatal depressive symptoms. Relevant literature evaluating a role for inflammation in depression in the unique context of pregnancy is both limited and inconsistent, and further exploration is merited.

Anti-cytokine agents for anhedonia: targeting inflammation and the immune system to treat dimensional disturbances in depression

The etiology of mood disorders is mechanistically heterogeneous, underscoring the need for a dimensional approach to identify and develop targeted treatments in psychiatry. Accumulating evidence implicates inflammation as an important contributor to the pathophysiology of depression and presents the immune system as a viable therapeutic target that may be more proximate to the pathogenic nexus of brain-based disorders in specific subpopulations. Anhedonia is a transdiagnostic (e.g. Parkinson's disease, diabetes mellitus, rheumatic diseases), yet specific, and clinically relevant symptom dimension subserved by well-characterized neurobiological and neurophysiological substrates of the positive valence systems (PVS). Brain circuits, nodes, and networks, as well as cellular and molecular pathways (e.g. dopaminergic transmission; excitotoxicity; synaptic plasticity), subserving anhedonia are preferentially affected by inflammatory processes. To our knowledge, no published randomized, controlled clinical trial in populations with mood disorders has, to date, primarily sought to determine the effects of an anti-inflammatory agent on PVS functions or pathophysiology. Three ongoing clinical trials aim to investigate the effects of anti-TNF-alpha biologic infliximab on measures of anhedonia [ClinicalTrials.gov identifier: NCT02363738], motivational behavior and circuitry [ClinicalTrials.gov identifier: NCT03006393], and glutamatergic changes in the basal ganglia [ClinicalTrials.gov identifier: NCT03004443] in clinical populations with unipolar or bipolar depression. Positive results would further instantiate the relevance of inflammatory processes and the immune system in the pathophysiology of mood disorders and provide the impetus to develop scalable treatments targeting inflammation and the immune system to mitigate transdiagnostic, dimensional disturbances in brain-based disorders.

Metabolomics approach in the investigation of depression biomarkers in pharmacologically induced immune-related depression

Background

The aim of this study was to identify previously unrecognised biological pathways and biomarkers that might expand the inflammatory hypothesis of depression.

Methods

Broad metabolomics analyses in plasma samples from 31 chronic hepatitis C-infected patients with and without immune-related depression were carried out using the Absolute IDQ p180 kit—a targeted metabolomics approach of combined direct flow injection and liquid chromatography that measures acylcarnitines, amino acids, biogenic amines, glycerophospholipids, sphingolipids, and sugars.

Results

The measurements showed that the average concentration of the branched-chain amino acid isoleucine was significantly lower in depressive HCV patients in comparison to non-depressive HCV patients [depression group: Median 51.35 (43.4–60.2 μmol/L) vs. Median 62.10 (38.4–81.7 μmol/L); U = -2.958; p = 0.002]. All other amino acids, acylcarnitines, biogenic amines, glycerophospholipids, sphingolipids, sugars, liver enzymes and thyroid levels showed no statistically significant differences.

Conclusions

The results of the present study suggest that the branched-chain amino acid isoleucine might play a role in the pathophysiology of immune-related major depression, which expands existing knowledge about inflammatory hypothesis of depression.

The neuroscience of depressive disorders: A brief review of the past and some considerations about the future

Depression is a common and debilitating mental health condition whose underlying aetiology and pathophysiology is still relatively poorly understood. In this article, we first turn to the past and briefly review what neuroscientific investigations have taught us so far about depression. In doing so, we cover neurochemical, neuroendocrine, immunological, functional and structural anatomical, and cognitive levels of description. We then turn our attention to the future and discuss where the field might be moving in the years to come. We argue that future developments may rely on three important lines of enquiry: first, the development of an integrated neuroscientific model of depression and its treatment in which different levels of description can be mechanistically linked, and in which distinct pathophysiological trajectories leading to depressive symptomatology can be identified. Second, the continued search for potentially overlooked pathophysiological factors, especially outside the immediate boundaries of the brain. And third, the improvement in translation of neuroscientific insights to aid and advance clinical practice and research.

Gut-brain actions underlying comorbid anxiety and depression associated with inflammatory bowel disease

IntroductionInflammatory bowel disease (IBD) is a chronic relapsing and remitting disorder characterised by inflammation of the gastrointestinal tract. There is a growing consensus that IBD is associated with anxiety- and depression-related symptoms. Psychological symptoms appear to be more prevalent during active disease states with no difference in prevalence between Crohn's disease and ulcerative colitis. Behavioural disturbances including anxiety- and depression-like symptoms have also been observed in animal models of IBD.

RESULTS

The likely mechanisms underlying the association are discussed with particular reference to communication between the gut and brain. The close bidirectional relationship known as the gut-brain axis includes neural, hormonal and immune communication links. Evidence is provided for a number of interacting factors including activation of the inflammatory response system in the brain, the hypothalamic-pituitary-adrenal axis, and brain areas implicated in altered behaviours, changes in blood brain barrier integrity, and an emerging role for gut microbiota and response to probiotics in IBD.DiscussionThe impact of psychological stress in models of IBD remains somewhat conflicted, however, it is weighted in favour of stress or early stressful life events as risk factors in the development of IBD, stress-induced exacerbation of inflammation and relapse.

CONCLUSION

It is recommended that patients with IBD be screened for psychological disturbance and treated accordingly as intervention can improve quality of life and may reduce relapse rates.

Protocol for the insight study: a randomised controlled trial of single-dose tocilizumab in patients with depression and low-grade inflammation

INTRODUCTION

Observational studies indicate a potentially causal role for interleukin 6 (IL-6), a proinflammatory cytokine, in pathogenesis of depression, but interventional studies based on patients with depression have not been conducted. Tocilizumab, anti-inflammatory drug, is a humanised monoclonal antibody that inhibits IL-6 signalling and is licensed in the UK for treatment of rheumatoid arthritis. The main objectives of this study are to test whether IL-6 contributes to the pathogenesis of depression and to examine potential mechanisms by which IL-6 affects mood and cognition. A secondary objective is to compare depressed participants with and without evidence of low-grade systemic inflammation.

METHODS AND ANALYSIS

This is a proof-of-concept, randomised, parallel-group, double-blind, placebo-controlled clinical trial. Approximately 50 participants with International Classification of Diseases 10th revision (ICD-10) diagnosis of depression who have evidence of low-grade inflammation, defined as serum high-sensitivity C reactive protein (hs-CRP) level ≥3 mg/L, will receive either a single intravenous infusion of tocilizumab or normal saline. Blood samples, behavioural and cognitive measures will be collected at baseline and after infusion around day 7, 14 and 28. The primary outcome is somatic symptoms score around day 14 postinfusion. In addition, approximately, 50 depressed participants without low-grade inflammation (serum hs-CRP level <3 mg/L) will complete the same baseline assessments as the randomised cohort.

ETHICS AND DISSEMINATION

The study has been approved by the South Central-Oxford B Research Ethics Committee (REC) (Reference: 18/SC/0118). Study findings will be published in peer-review journals. Findings will be also disseminated by conference/departmental presentations and by social and traditional media.

TRIAL REGISTRATION NUMBER

ISRCTN16942542; Pre-results.

Association of T and non-T cell cytokines with anhedonia: Role of gender differences

OBJECTIVE

Among individual depressive symptoms, anhedonia has been reliably associated with activation of the innate immune response. However, it is unclear whether this association extends to T cell cytokines and if gender differentially affects this association.

METHOD

Concentrations of T (IL-17, T-helper (Th) 1- and Th2-) and non-T cell cytokines were measured in plasma using the Bioplex Pro™ human cytokine multiplex kit in Combining Medications to Enhance Depression Outcomes (CO-MED) trial participants who provided plasma at baseline (n = 166). Anhedonia was measured with three items of the clinician-rated Inventory of Depressive Symptomatology and depression severity (minus anhedonia item) was measured with Quick Inventory of Depression Severity Self-Report version (modified-QIDS-SR). Separate generalized linear models for anhedonia and modified-QIDS-SR as dependent variables were conducted with IL-17, Th1-, Th2-, and non-T cell- cytokines as primary independent variables and gender, body mass index (BMI), and age as covariates. Exploratory analyses included gender-by-biomarker interactions.

RESULTS

Higher levels of IL-17 (p = 0.032), Th1- (p = 0.002), Th2-(p = 0.001) and non-T-(p = 0.009) cell markers were associated with greater severity of anhedonia controlling for BMI, age, and gender. Gender also had a significant main effect on anhedonia, however, there was a significant gender by immune marker interaction only for IL-17 (p = 0.050). Anhedonia severity increased with higher IL-17 in males (r = 0.42, p = 0.003) but not in females (r = 0.09, p = 0.336). Only non-T cell markers were associated with the modified-QIDS-SR, and there were no significant gender-specific associations with this variable.

CONCLUSIONS

T and non-T cell-related inflammatory markers were associated with greater severity of anhedonia, while gender moderated the association of IL-17 with anhedonia in patients with major depressive disorder.

Role of Kynurenine pathway and its metabolites in mood disorders: A systematic review and meta-analysis of clinical studies

Activation of the kynurenine pathway is one of the described mechanisms by which inflammation can induce depression. It involves multiple pathways including interference with the bioavailability of tryptophan central to the synthesis of the neurotransmitter serotonin. In this systematic review, we examine the relationship between kynurenine metabolites (kynurenine, kynurenic acid, tryptophan, quinolinic acid, the ratio of kynurenine and tryptophan) and mood disorders by conducting a meta-analysis. Fifty-six studies were identified, 21 met inclusion criteria and 14 were deemed suitable (9 investigating unipolar depression and 5 bipolar disorder). We found decreased levels of kynurenine in unipolar major depression vs. healthy controls but studies were significantly heterogeneous in nature. No significant differences were found in tryptophan levels or kynurenine/tryptophan ratios. Kynurenine metabolites are likely to play a role in major depression but an exact etiological role in mood disorder seem complex and requires further research.

Depression and sterile inflammation: Essential role of danger associated molecular patterns

Stress is a major risk factor for psychiatric disorder including major depressive disorder (MDD) and can induce inflammation, which is known to be dysregulated in depression. Several clinical and pre-clinical studies have demonstrated a strong association between depressive symptoms and the expression of factors that increase inflammation. Conversely, administration of anti-inflammatory agents has been shown to ameliorate depressive symptoms, demonstrating the importance of inflammation as a mediator of depression. Although it is clear that inflammation plays a role in the pathophysiology of depression, the mechanism by which inflammation is activated in mood disorders remains unclear. To address this issue, studies have investigated the role of pattern recognition receptor (PRR) activation in stress-induced inflammation and mood disorders. However, the identification of the endogenous factors, referred to as danger-associated molecular patterns (DAMP) that activate these receptors remains understudied. Here we review the role of DAMPs in depression and highlight the clinical evidence for elevation of DAMP signaling in MDD patients and in pre-clinical animal stress models of depression.

Changes in the tryptophan-kynurenine axis in association to therapeutic response in clinically depressed patients undergoing psychiatric rehabilitation

INTRODUCTION

In recent decades a number of studies have shown an association between the Tryptophan (Trp)-Kynurenine (Kyn) axis and neuropsychiatric disorders. However, the role of the Trp-Kyn pathway on the affective status in a general psychiatric cohort requires clarification. This study aimed to measure peripheral changes in Trp, Kyn and the Kyn/Trp-ratio as well as in the inflammatory markers high sensitive C-reactive protein (hsCRP) and interleukine-6 (IL-6) in individuals undergoing a six-week course of intensive treatment program comparing subgroups of treatment responders and non-responders.

METHODS

In this investigation 87 currently depressed individuals with a life-time history of depressive disorders were divided into treatment responders (n = 48) and non-responders (n = 39). The individuals were selected for an extreme group comparison out of 598 patients undergoing a 6-week psychiatric rehabilitation program in Austria. Responders were defined according to great changes in Becks Depression Inventory (BDI-II) between time of admission and discharge (BDI-II > 29 to BDI-II <14), while non-responders had no or minimal changes (BDI >20, max. 4 points change over time). Differences in the levels of Trp, Kyn, and the Kyn/Trp ratio as well as levels of hsCRP and IL-6, were compared between groups. Differences were analyzed at the time of admission as well as at discharge.

RESULTS

A significant group x time interaction was found for Kyn [F(1.82) = 5.79; p = 0.018] and the Kyn/Trp ratio [F(1.85) = 4.01, p = 0.048]. Importantly, Kyn increased significantly in the non-responder group, while the Kyn/Trp ratio decreased significantly in the responder group over time. Furthermore, changes in Kyn as well as hsCRP levels correlated significantly with changes in the body mass index over time (Kyn: r=0.24, p = 0.030; hsCRP: r=0.25, p = 0.021). No significant interactions were found for Trp and hsCRP, although they increased significantly over time.

DISCUSSION

Given the limitations of the study, we could show that the therapeutic response to a multimodal treatment in clinically depressed patients not receiving cytokine treatment is associated with changes in Kyn levels and the Kyn/Trp ratio as well as with hsCRP. However, it is too early to draw any causal conclusion. Future research should clarify relevant clinical and neurobiological parameters associated with changes in Kyn levels and Kyn/Trp ratio, especially in regard to clinical response.

Deciphering sex differences in the immune system and depression

Certain mood disorders and autoimmune diseases are predominately female diseases but we do not know why. Here, we explore the relationship between depression and the immune system from a sex-based perspective. This review characterizes sex differences in the immune system in health and disease. We explore the contribution of gonadal and stress hormones to immune function at the cellular and molecular level in the brain and body. We propose hormonal and genetic sex specific immune mechanisms that may contribute to the etiology of mood disorders.

Low tumor necrosis factor-α levels predict symptom reduction during electroconvulsive therapy in major depressive disorder

OBJECTIVE

Changes in the tumor necrosis factor-α (TNFα) have been associated with major depressive disorder (MDD). Findings concerning the effects of electroconvulsive therapy (ECT) on the TNFα level have been contradictory. The aim was to examine the immediate and long-term changes in the TNFα level and their associations with symptom reduction in patients with MDD during ECT.

METHOD

The study included 30 patients with MDD. Their TNFα levels were measured at baseline and 2 and 4 hr after the first, fifth and last ECT session. Depressive symptoms were assessed with the Montgomery-Asberg Depression Rating Scale (MADRS).

RESULTS

The TNFα level decreased from baseline to the 2- and 4-hr measurements. There was a correlation between the first ECT session TNFα levels and the relative symptom reduction according to the MADRS score after the ECT series. Both the first (baseline) ECT and 4-hr TNFα levels were lower in responders than in nonresponders.

CONCLUSION

ECT consistently induced a decrease in the TNFα level after each studied session. A low TNFα level at the first ECT appeared to predict a symptom reduction. These findings suggest that TNFα might have a role in the pathogenesis in MDD and in the mechanism of action of ECT.

Sex differences in the neuro-immune consequences of stress: Focus on depression and anxiety

Women appear to be more vulnerable to the depressogenic effects of inflammation than men. Chronic stress, one of the most pertinent risk factors of depression and anxiety, is known to induce behavioral and affective-like deficits via neuroimmune alterations including activation of the brain's immune cells, pro-inflammatory cytokine expression, and subsequent changes in neurotransmission and synaptic plasticity within stress-related neural circuitry. Despite well-established sexual dimorphisms in the stress response, immunity, and prevalence of stress-linked psychiatric illnesses, much of current research investigating the neuroimmune impact of stress remains exclusively focused on male subjects. We summarize and evaluate here the available data regarding sex differences in the neuro-immune consequences of stress, and some of the physiological factors contributing to these differences. Furthermore, we discuss the extent to which sex differences in stress-related neuroinflammation can account for the overall female bias in stress-linked psychiatric disorders including major depressive disorder and anxiety disorders. The currently available evidence from rodent studies does not unequivocally support the peripheral inflammatory changes seen in women following stress. Replication of many recent findings in stress-related neuroinflammation in female subjects is necessary in order to build a framework in which we can assess the extent to which sex differences in stress-related inflammation contribute to the overall female bias in stress-related affective disorders.

Translational Functional Neuroimaging in the Explanation of Depression

Translation as a notion and procedure is deeply embodied in medical science and education. Translation includes the possibility to translate data across disciplines to improve diagnosis and treatment procedures. The evidence accumulated using translation serves as a vehicle for reification of medical diagnoses. There are promising, established post hoc correlations between the different types of clinical tools (interviews and inventories) and neuroscience. The various measures represent statistical correlations that must now be integrated into diagnostic standards and procedures but this, as a whole, is a step forward towards a better understanding of the mechanisms underlying psychopathology in general and depression in particular. Here, we focus on functional magnetic resonance imaging studies using a trans-disciplinary approach and attempt to establish bridges between the different fields. We will selectively highlight research areas such as imaging genetics, imaging immunology and multimodal imaging, as related to the diagnosis and management of depression.

Immunopsychiatry: important facts

Accumulating evidence indicate a role for the immune system particularly inflammation and autoimmunity in the aetiology of major psychiatric disorders such as depression and schizophrenia. In this paper, we discuss some of the key advances in immunopsychiatry in order to highlight to psychiatrists and other health professionals how an increased understanding of this field might enhance our knowledge of illness mechanism and approaches to treatment. We present a brief overview of clinical research that link inflammation and autoimmunity with depression and psychosis, including potential role of inflammation in treatment response, current evidence for the effectiveness of immune-modulating treatment for depression and psychosis, and possible role of inflammation in common physical comorbidities for these disorders such as coronary heart disease and diabetes mellitus. Gaining a better understanding of the role of immune system could be paradigm changing for psychiatry. We need collaborations between clinicians and scientists to deliver high-quality translational research in order to fully realise the clinical potential of this exciting and rapidly expanding field.

Prevalence and Incidence of Depression during Interferon-Based Antiviral Therapy in Chronic Hepatitis C Patients in the Republic of Korea

BACKGROUND/AIMS

The association between depression and chronic hepatitis C virus (HCV) infection or pegylated interferon α and ribavirin therapy (PR therapy) has not been extensively studied in Korea. We aimed to clarify the prevalence of depression and its incidence during PR therapy in chronic hepatitis C (CHC) patients.

METHODS

In this prospective, multicenter study, 114 CHC patients were screened for depression using two self-reported scales, the Beck Depression Inventory-I (BDI-I) and the Hospital Anxiety and Depression scale (HADS). The incidence of depression during PR therapy was evaluated in 62 patients who underwent PR therapy during the study period.

RESULTS

The prevalence of baseline depression was 17.5% according to the BDI-I score ≥10 criterion and 4.4% according to the HADS-D score ≥8 criterion in the 114 CHC patients, and it was significantly associated with an unmarried state. During PR therapy, depression developed in 34.6% according to the BDI-I scale and 29.5% according to the HADS-D, which negatively affected sustained virologic response (SVR).

CONCLUSIONS

The prevalence of depression in Korean CHC patients appears to be low compared to that in Western patients; however, its incidence during PR therapy (approximately 30%) was similar to that of other populations, which led to a lower SVR rate. Active screening and multidisciplinary management of depression during PR therapy is warranted.

Depression and Chronic Liver Diseases: Are There Shared Underlying Mechanisms?

The occurrence of depression is higher in patients with chronic liver disease (CLD) than that in the general population. The mechanism described in previous studies mainly focused on inflammation and stress, which not only exists in CLD, but also emerges in common chronic diseases, leaving the specific mechanism unknown. This review was to summarize the prevalence and risk factors of depression in CLD including chronic hepatitis B, chronic hepatitis, alcoholic liver disease, and non-alcoholic fatty liver disease, and to point out the possible underlying mechanism of this potential link. Clarifying the origins of this common comorbidity (depression and CLD) may provide more information to understand both diseases.

Toll-like receptor signaling and stages of addiction

BACKGROUND

Athina Markou and her colleagues discovered persistent changes in adult behavior following adolescent exposure to ethanol or nicotine consistent with increased risk for developing addiction. Building on Dr. Markou's important work and that of others in the field, researchers at the Bowles Center for Alcohol Studies have found that persistent changes in behavior following adolescent stress or alcohol exposure may be linked to induction of immune signaling in brain.

AIM

This study aims to illuminate the critical interrelationship of the innate immune system (e.g., toll-like receptors [TLRs], high-mobility group box 1 [HMGB1]) in the neurobiology of addiction.

METHOD

This study reviews the relevant research regarding the relationship between the innate immune system and addiction.

CONCLUSION

Emerging evidence indicates that TLRs in brain, particularly those on microglia, respond to endogenous innate immune agonists such as HMGB1 and microRNAs (miRNAs). Multiple TLRs, HMGB1, and miRNAs are induced in the brain by stress, alcohol, and other drugs of abuse and are increased in the postmortem human alcoholic brain. Enhanced TLR-innate immune signaling in brain leads to epigenetic modifications, alterations in synaptic plasticity, and loss of neuronal cell populations, which contribute to cognitive and emotive dysfunctions. Addiction involves progressive stages of drug binges and intoxication, withdrawal-negative affect, and ultimately compulsive drug use and abuse. Toll-like receptor signaling within cortical-limbic circuits is modified by alcohol and stress in a manner consistent with promoting progression through the stages of addiction.

Association of Changes in Mood Status and Psychosocial Well-Being with Depression During Interferon-Based Treatment for Hepatitis C

OBJECTIVE

The aims of this prospective study were to investigate temporal changes in mood status and distress level, as well as the development of depression, during pegylated interferon (PEG-IFN)-based treatment of patients with chronic hepatitis C (CHC). We also explored whether baseline demographic, psychiatric, and personality traits predicted the evolution of depression.

METHODS

CHC patients without depression were screened with laboratory tests; psychiatric interviews; and evaluations of mood symptoms, level of distress, and personality traits. A total of 67 treatment-naïve patients with CHC were consecutively treated with PEG-IFN-α-2a plus ribavirin for 48 (genotype 1, n=29) or 24 (genotype 2, n=38) weeks. Patients were followed prospectively every 4 weeks during the treatment period.

RESULTS

Seven patients (10.4%) were diagnosed with major depressive disorder (MDD), and eight (11.9%) developed subsyndromal depression. Times to onset of MDD and subsyndromal depression were 6.67±5.01 and 11.11±5.58 weeks, respectively, after initiation of treatment. Patients who developed MDD had significantly increased fatigue and anxiety and poor psychological well-being during the course of treatment. Pretreatment subthreshold mood symptoms were a significant predictor of depression.

CONCLUSION

An early psychiatric assessment may be helpful in improving psychological well-being in those with CHC, leading to adherence to PEG-IFN-based treatment.

Emerging RNA editing biomarkers will foster drug development

Unanticipated adverse drug reactions (ADRs) on the central nervous system are a major cause of clinical attrition and market withdrawal. Current practices for their prospective assessment still lean on extensive analysis of rodent behaviour despite their highly controversial predictive value. Human-derived in vitro models that objectively quantify mechanism-related biomarkers can greatly contribute to better ADR prediction at early developmental stages. Adenosine-to-inosine RNA editing constitutes a physiological cellular process that translates environmental cues by regulating protein function at the synaptic level in health and disease. Robust solutions based on NGS-based quantification of RNA editing biomarkers have emerged to predict the likelihood of treatment-related suicidal ideation and behaviour allowing cost-effective high-throughput drug screening as a strategy for risk mitigation.

The role of neuroimmune signaling in alcoholism

Alcohol consumption and stress increase brain levels of known innate immune signaling molecules. Microglia, the innate immune cells of the brain, and neurons respond to alcohol, signaling through Toll-like receptors (TLRs), high-mobility group box 1 (HMGB1), miRNAs, pro-inflammatory cytokines and their associated receptors involved in signaling between microglia, other glia and neurons. Repeated cycles of alcohol and stress cause a progressive, persistent induction of HMGB1, miRNA and TLR receptors in brain that appear to underlie the progressive and persistent loss of behavioral control, increased impulsivity and anxiety, as well as craving, coupled with increasing ventral striatal responses that promote reward seeking behavior and increase risk of developing alcohol use disorders. Studies employing anti-oxidant, anti-inflammatory, anti-depressant, and innate immune antagonists further link innate immune gene expression to addiction-like behaviors. Innate immune molecules are novel targets for addiction and affective disorders therapies. This article is part of the Special Issue entitled "Alcoholism".

Peripheral Inflammatory Parameters in Late-Life Depression: A Systematic Review

Depressive disorders appear relatively frequently in older patients, and therefore represent an important disease burden worldwide. Given the high levels of inflammatory parameters found in depressed elderly patients, the "inflammaging" hypothesis is gaining strength. In this systematic review, we summarize current evidence regarding the relationship between inflammatory parameters and late-life depression, with a unique focus on longitudinal studies to guarantee temporality. According to the data summarized in this review, the levels of some proinflammatory parameters-especially interleukin (IL)-8, IL-6, and tumor necrosis factor (TNF)-α-could serve as biomarkers for the future development of depressive symptoms in elderly patients. Proinflammatory cytokines seem to be associated with the future development of clinically significant depression, irrespective of baseline scores, thus indicating that inflammation temporally precedes and increases depression risk. As insufficient research has been conducted in this field, further prospective studies are clearly warranted.

A Survey on the Prevalence of Depression in Blood Donors with Hepatitis C in Shiraz

BACKGROUND

Depression is the most common psychiatric disorder associated with hepatitis C.

OBJECTIVES

This study aimed to survey the prevalence rate of depression in patients with Hepatitis C Virus (HCV) before they were aware of their HCV test result.

METHODS

This cross-sectional study was conducted on all blood donors with confirmed positive HCV test results who donated blood between March 21, 2012 to March 21, 2013 at Fars blood transfusion center in Iran as case group and age- and sex-matched blood donors with negative screening test results as control group. A semi-structured interview based on DSM IV-TR depressive disorder criteria and Beck depression inventory (BDI) was conducted. BDI contained 21 items, each scored from 0 to 3 and total score of 0 to 63 for the whole scale computed by summing up all the items. A cut-off score of ≥ 19 indicated clinically significant depressive symptoms. The prevalence rate and risk factors of depression were determined.

RESULTS

The most frequent risk factors for HCV infection were intravenous drug abuse (59.3%), unsafe sexual contact (30.5%), and history of being imprisoned (25.4%). The prevalence rate of depression in the HCV group was 55.9 % (95% CI: 42.99% - 68.87%) that was significantly higher than the corresponding rate of the control group as 17.7 % ( 95% CI: 8.49% - 28.79%) (P < 0.001). The severity of depression was also more in the HCV group (P < 0.001). Besides, the prevalence rate of depression was higher among HCV patients with lower education level, previous history of drug abuse, unsafe sexual contact, and previous history of psychiatric diseases. The prevalence rate of depression was higher in the case group even after adjusting for other variables.

CONCLUSIONS

Our study underlined the remarkable prevalence of depression among HCV patients. Therefore, designing depression screening tests is suggested to help such patients before starting the treatment.

Mast cells' involvement in inflammation pathways linked to depression: evidence in mastocytosis

Converging sources of evidence point to a role for inflammation in the development of depression, fatigue and cognitive dysfunction. More precisely, the tryptophan (TRP) catabolism is thought to play a major role in inflammation-induced depression. Mastocytosis is a rare disease in which chronic symptoms, including depression, are related to mast cell accumulation and activation. Our objectives were to study the correlations between neuropsychiatric features and the TRP catabolism pathway in mastocytosis in order to demonstrate mast cells' potential involvement in inflammation-induced depression. Fifty-four patients with mastocytosis and a mean age of 50.1 years were enrolled in the study and compared healthy age-matched controls. Depression and stress were evaluated with the Beck Depression Inventory revised and the Perceived Stress Scale. All patients had measurements of TRP, serotonin (5-HT), kynurenine (KYN), indoleamine 2,3-dioxygenase 1 (IDO1) activity (ratio KYN/TRP), kynurenic acid (KA) and quinolinic acid (QA). Patients displayed significantly lower levels of TRP and 5-HT without hypoalbuminemia or malabsorption, higher IDO1 activity, and higher levels of KA and QA, with an imbalance towards the latter. High perceived stress and high depression scores were associated with low TRP and high IDO1 activity. In conclusion, TRP metabolism is altered in mastocytosis and correlates with perceived stress and depression, demonstrating mast cells' involvement in inflammation pathways linked to depression.

Side effect profile similarities shared between antidepressants and immune-modulators reveal potential novel targets for treating major depressive disorders

Background

Side effects, or the adverse effects of drugs, contain important clinical phenotypic information that may be useful in predicting novel or unknown targets of a drug. It has been suggested that drugs with similar side-effect profiles may share common targets. The diagnostic class, Major Depressive Disorder, is increasingly viewed as being comprised of multiple depression subtypes with different biological root causes. One ‘type’ of depression generating substantial interest today focuses on patients with high levels of inflammatory burden, indicated by elevated levels of C-reactive proteins (CRP) and pro-inflammatory cytokines such as interleukin 6 (IL-6). It has been suggested that drugs targeting the immune system may have beneficial effect on this subtype of depressed patients, and several studies are underway to test this hypothesis directly. However, patients have been treated with both anti-inflammatory and antidepressant compounds for decades. It may be possible to exploit similarities in clinical readouts to better understand the antidepressant effects of immune-related drugs.

Methods

Here we explore the space of approved drugs by comparing the drug side effect profiles of known antidepressants and drugs targeting the immune system, and further examine the findings by comparing the human cell line expression profiles induced by them with those induced by antidepressants.

Results

We found 7 immune-modulators and 14 anti-inflammatory drugs sharing significant side effect profile similarities with antidepressants. Five of the 7 immune modulators share most similar side effect profiles with antidepressants that modulate dopamine release and/or uptake. In addition, the immunosuppressant rapamycin and the glucocorticoid alclometasone induces transcriptional changes similar to multiple antidepressants.

Conclusions

These findings suggest that some antidepressants and some immune-related drugs may affect common molecular pathways. Our findings support the idea that certain medications aimed at the immune system may be helpful in relieving depressive symptoms, and suggest that it may be of value to test immune-modulators for antidepressant-like activity in future proof-of-concept studies.

Long-Term Fine Particulate Matter Exposure and Major Depressive Disorder in a Community-Based Urban Cohort

BACKGROUND

Previous studies have associated short-term air pollution exposure with depression. Although an animal study showed an association between long-term exposure to particulate matter ≤ 2.5 μm (PM2.5) and depression, epidemiological studies assessing the long-term association are scarce.

OBJECTIVE

We aimed to determine the association between long-term PM2.5 exposure and major depressive disorder (MDD).

METHODS

A total of 27,270 participants 15-79 years of age who maintained an address within the same districts in Seoul, Republic of Korea, throughout the entire study period (between 2002 and 2010) and without a previous MDD diagnosis were analyzed. We used three district-specific exposure indices as measures of long-term PM2.5 exposure. Cox proportional hazards models adjusted for potential confounding factors and measured at district and individual levels were constructed. We further conducted stratified analyses according to underlying chronic diseases such as diabetes mellitus, cardiovascular disease, and chronic obstructive pulmonary disease.

RESULTS

The risk of MDD during the follow-up period (2008-2010) increased with an increase of 10 μg/m3 in PM2.5 in 2007 [hazard ratio (HR) = 1.44; 95% CI: 1.17, 1.78], PM2.5 between 2007 and 2010 (HR = 1.59; 95% CI: 1.02, 2.49), and 12-month moving average of PM2.5 until an event or censor (HR = 1.47; 95% CI: 1.14, 1.90). The association between long-term PM2.5 exposure and MDD was greater in participants with underlying chronic diseases than in participants without these diseases.

CONCLUSION

Long-term PM2.5 exposure increased the risk of MDD among the general population. Individuals with underlying chronic diseases are more vulnerable to long-term PM2.5 exposure.

CITATION

Kim KN, Lim YH, Bae HJ, Kim M, Jung K, Hong YC. 2016. Long-term fine particulate matter exposure and major depressive disorder in a community-based urban cohort. Environ Health Perspect 124:1547-1553; http://dx.doi.org/10.1289/EHP192.

Glial biomarkers in human central nervous system disease

There is a growing understanding that aberrant GLIA function is an underlying factor in psychiatric and neurological disorders. As drug discovery efforts begin to focus on glia-related targets, a key gap in knowledge includes the availability of validated biomarkers to help determine which patients suffer from dysfunction of glial cells or who may best respond by targeting glia-related drug mechanisms. Biomarkers are biological variables with a significant relationship to parameters of disease states and can be used as surrogate markers of disease pathology, progression, and/or responses to drug treatment. For example, imaging studies of the CNS enable localization and characterization of anatomical lesions without the need to isolate tissue for biopsy. Many biomarkers of disease pathology in the CNS involve assays of glial cell function and/or response to injury. Each major glia subtype (oligodendroglia, astroglia and microglia) are connected to a number of important and useful biomarkers. Here, we describe current and emerging glial based biomarker approaches for acute CNS injury and the major categories of chronic nervous system dysfunction including neurodegenerative, neuropsychiatric, neoplastic, and autoimmune disorders of the CNS. These descriptions are highlighted in the context of how biomarkers are employed to better understand the role of glia in human CNS disease and in the development of novel therapeutic treatments. GLIA 2016;64:1755-1771.

Region-specific alterations of A-to-I RNA editing of serotonin 2c receptor in the cortex of suicides with major depression

Brain region-specific abnormalities in serotonergic transmission appear to underlie suicidal behavior. Alterations of RNA editing on the serotonin receptor 2C (HTR2C) pre-mRNA in the brain of suicides produce transcripts that attenuate 5-HT2CR signaling by impairing intracellular G-protein coupling and subsequent intracellular signal transduction. In brain, the distribution of RNA-editing enzymes catalyzing deamination (A-to-I modification) shows regional variation, including within the cerebral cortex. We tested the hypothesis that altered pre-mRNA 5-HT2CR receptor editing in suicide is region-specific. To this end, we investigated the complete 5-HT2CR mRNA-editing profile in two architectonically distinct cortical areas involved in mood regulation and decision-making in a clinically well-characterized cohort of age- and sex-matched non-psychiatric drug-free controls and depressed suicides. By using an original biochemical detection method, that is, capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), we corroborated the 5-HT2CR mRNA-editing profile previously described in the dorsolateral prefrontal cortex (Brodmann area 9 (BA9)). Editing of 5-HT2CR mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Compared with non-psychiatric control individuals, alterations of editing levels of 5-HT2CR mRNA were detected in both cortical areas of depressed suicides. A marked increase in editing on 5-HT2CR was especially observed in the anterior cingulate cortex in suicides, implicating this cortical area in suicide risk. The results suggest that region-specific changes in RNA editing of 5-HT2CR mRNA and deficient receptor function likely contribute to the etiology of major depressive disorder or suicide.

Associations of Blood Cadmium Levels With Depression and Lower Handgrip Strength in a Community-Dwelling Elderly Population: A Repeated-Measures Panel Study

BACKGROUND

Although biologically plausible, few studies have linked cadmium exposure to depression or muscle strength. Herein, we hypothesized that blood cadmium concentrations are associated with depression and lower handgrip strength in a community-dwelling elderly population.

METHODS

Data from 983 elderly participants who completed up to 3 surveys between 2012 and 2015 were analyzed. At every survey, we assessed depressive status using the Korean version of the Geriatric Depression Scale-Short Form (SGDS-K) and measured handgrip strength and blood cadmium levels (mean, 1.24 μg/L). We evaluated the associations of cadmium with depression using generalized linear mixed models, and handgrip strength using linear mixed models. All models were adjusted for sociodemographic factors, lifestyle factors including active and passive smoking, weight, height, and comorbidity status.

RESULTS

Interquartile-range increase (0.645 μg/L) in blood cadmium levels was associated with depression defined as SGDS-K score ≥8 (odds ratio = 1.27, 95% confidence interval: 1.06, 1.52) and lower handgrip strength (right hand: β = -0.40, 95% confidence interval: -0.75, -0.09; left hand: β = -0.36, 95% confidence interval: -0.69, -0.04). The association between cadmium levels and handgrip strength was robust after further adjustment for depressive status, although it attenuated in size by 14.7%-18.0%.

CONCLUSIONS

After adjusting for potential confounders, blood cadmium concentrations were associated with depression and lower handgrip strength in an elderly population. The participants' depressive status partially mediated the association between cadmium levels and handgrip strength.

Inflammatory insults and mental health consequences: does timing matter when it comes to depression?

It has become widely accepted that the immune system, and specifically increased levels of inflammation, play a role in the development of depression. However, not everyone with increased inflammation develops depression, and as with all other diseases, there are risk factors that may contribute to an increased vulnerability in certain individuals. One such risk factor could be the timing of an inflammatory exposure. Here, using a combination of PubMed, EMBASE, Ovid Medline and PsycINFO, we systematically reviewed whether exposure to medically related inflammation in utero, in childhood, and in adolescence, increases the risk for depression in adulthood. Moreover, we tried to determine whether there was sufficient evidence to identify a particular time point during the developmental trajectory in which an immune insult could be more damaging. While animal research shows that early life exposure to inflammation increases susceptibility to anxiety- and depressive-like behaviour, human studies surprisingly find little evidence to support the notion that medically related inflammation in utero and in adolescence contributes to an increased risk of developing depression in later life. However, we did find an association between childhood inflammation and later life depression, with most studies reporting a significantly increased risk of depression in adults who were exposed to inflammation as children. More robust clinical research, measuring direct markers of inflammation throughout the life course, is greatly needed to expand on, and definitively address, the important research questions raised in this review.

Comorbidity between depression and inflammatory bowel disease explained by immune-inflammatory, oxidative, and nitrosative stress; tryptophan catabolite; and gut-brain pathways

The nature of depression has recently been reconceptualized, being conceived as the clinical expression of activated immune-inflammatory, oxidative, and nitrosative stress (IO&NS) pathways, including tryptophan catabolite (TRYCAT), autoimmune, and gut-brain pathways. IO&NS pathways are similarly integral to the pathogenesis of inflammatory bowel disease (IBD). The increased depression prevalence in IBD associates with a lower quality of life and increased morbidity in IBD, highlighting the role of depression in modulating the pathophysiology of IBD.This review covers data within such a wider conceptualization that better explains the heightened co-occurrence of IBD and depression. Common IO&NS underpinning between both disorders is evidenced by increased pro-inflammatory cytokine levels, eg, interleukin-1 (IL-1) and tumor necrosis factor-α, IL-6 trans-signalling; Th-1- and Th-17-like responses; neopterin and soluble IL-2 receptor levels; positive acute phase reactants (haptoglobin and C-reactive protein); lowered levels of negative acute phase reactants (albumin, transferrin, zinc) and anti-inflammatory cytokines (IL-10 and transforming growth factor-β); increased O&NS with damage to lipids, proteinsm and DNA; increased production of nitric oxide (NO) and inducible NO synthase; lowered plasma tryptophan but increased TRYCAT levels; autoimmune responses; and increased bacterial translocation. As such, heightened IO&NS processes in depression overlap with the biological underpinnings of IBD, potentially explaining their increased co-occurrence. This supports the perspective that there is a spectrum of IO&NS disorders that includes depression, both as an emergent comorbidity and as a contributor to IO&NS processes. Such a frame of reference has treatment implications for IBD when "comorbid" with depression.

Urinary phthalate metabolites and depression in an elderly population: National Health and Nutrition Examination Survey 2005-2012

Previous animal studies have demonstrated that phthalate exposure is associated with depression-like behaviors. However, no human study has explored this relationship. We explored the association between urinary phthalate metabolite concentrations and depression in a nationally representative sample of the U.S. elderly population. We analyzed 2030 participants aged 60 years or older with available data on phthalates and depression from the 2005 to 2012 National Health and Nutrition Examination Survey (NHANES). We selected 10 urinary phthalate metabolites with a weighted detection rate >60%. Depression was defined as a 9-item Patient Health Questionnaire score ≥10. The models were adjusted for age, sex, race/ethnicity, education level, income-to-poverty ratio, health insurance coverage, marital status, smoking status, alcohol consumption, moderate physical activity, body mass index, comorbidity status, NHANEs cycle, and urinary creatinine levels. One-unit increases in log-transformed mono-(3-carboxypropyl) phthalate (MCPP) (odds ratio [OR]=1.24, 95% confidence interval [CI]=1.02-1.52) and mono(carboxynonyl) phthalate (MCNP) (OR=1.42, 95% CI=1.15-1.75) were positively associated with depression. When we stratified the urinary phthalate metabolites into quartiles, the highest quartiles (Q4) of MCNP (OR=2.57, 95% CI=1.25-5.27) and mono-n-butyl phthalate (MBP) (OR=2.40, 95% CI=1.10-5.22) were associated with depression compared with the lowest quartiles (Q1). Concentrations of urinary phthalate metabolites MCPP, MCNP, and MBP were positively associated with the risk of depression in a representative sample of the U.S. elderly population. However, the present cross-sectional study is hypothesis generating and the associations need to be investigated through further longitudinal studies.

The role of pro-inflammatory cytokines in neuroinflammation, neurogenesis and the neuroendocrine system in major depression

Cytokines are pleiotropic molecules with important roles in inflammatory responses. Pro-inflammatory cytokines and neuroinflammation are important not only in inflammatory responses but also in neurogenesis and neuroprotection. Sustained stress and the subsequent release of pro-inflammatory cytokines lead to chronic neuroinflammation, which contributes to depression. Hippocampal glucocorticoid receptors (GRs) and the associated hypothalamus-pituitary-adrenal (HPA) axis have close interactions with pro-inflammatory cytokines and neuroinflammation. Elevated pro-inflammatory cytokine levels and GR functional resistance are among the most widely investigated factors in the pathophysiology of depression. These two major components create a vicious cycle. In brief, chronic neuroinflammation inhibits GR function, which in turn exacerbates pro-inflammatory cytokine activity and aggravates chronic neuroinflammation. On the other hand, neuroinflammation causes an imbalance between oxidative stress and the anti-oxidant system, which is also associated with depression. Although current evidence strongly suggests that cytokines and GRs have important roles in depression, they are essential components of a whole system of inflammatory and endocrine interactions, rather than playing independent parts. Despite the evidence that a dysfunctional immune and endocrine system contributes to the pathophysiology of depression, much research remains to be undertaken to clarify the cause and effect relationship between depression and neuroinflammation.

Major depressive disorder and generalized anxiety disorder and response to treatment in hepatitis C patients in Egypt

OBJECTIVES

The aim of the study was to estimate the prevalence and associated correlates of major depressive disorder and generalized anxiety disorder in hepatitis C virus patients before and after treatment and to investigate the relationship between major depressive disorder and generalized anxiety disorder and treatment response.

METHODS

A total of 116 consecutive hepatitis C virus patients from hepatitis C virus treatment center in Zagazig city, Egypt, were included in the study and divided into treated group (N = 58) and untreated group (N = 58). All hepatitis C virus patients were screened for major depressive disorder and generalized anxiety disorder using hospital anxiety and depression scale, and those who screened positive were interviewed to confirm the diagnosis of major depressive disorder and generalized anxiety disorder using DSM-IV-TR diagnostic criteria. These measures were done at baseline and after 12 weeks of treatment or observation.

RESULTS

At baseline, 3.5% and 12.1% of hepatitis C virus patients (treated group) had major depressive disorder and generalized anxiety disorder, respectively. After 12 weeks of treatment 37.9% of hepatitis C virus patients (treated group) had major depressive disorder and 46.6% had generalized anxiety disorder. There was a significant statistical difference between hospital anxiety and depression scale scores for depression (3.3 ± 2.3 vs. 6.4 ± 3.2, t = 9.6, p = 0.001) and for anxiety (4.6 ± 2.4 vs. 7.3 ± 3.0, t = 10.2, p = 0.001) before and after treatment. There was also significant statistical difference between treated group and untreated group regarding hospital anxiety and depression scale scores after treatment and observation (depression, treated group 6.4 ± 3.2 vs. untreated group 4.0 ± 2.4, t = 3.7, p = 0.001; anxiety, treated group 7.3 ± 3.0 vs. untreated group 4.5 ± 2.3, t = 4.4, p = 0.001). There was no association between major depressive disorder and generalized anxiety disorder and treatment response.

CONCLUSIONS

Major depressive disorder and generalized anxiety disorder are common in hepatitis C virus patients after treatment with interferon and ribavirin and were not related to treatment response.

Quinolinic Acid Responses during Interferon-α-Induced Depressive Symptomatology in Patients with Chronic Hepatitis C Infection - A Novel Aspect for Depression and Inflammatory Hypothesis

BACKGROUND

The aim of this exploratory study is to gain for the first time a more comprehensive picture of the impact of changes of quinolinic acid concentrations on depressive symptomatology during and after IFN-α therapy.

METHODS

The quinolinic acid concentrations of 35 HCV patients are examined in a prospective survey over the entire period of IFN-α treatment as well as three months later at six different times (baseline, one, three, six and nine months after the beginning of IFN-α treatment, and after the end of treatment).

RESULTS

During IFN-α treatment Hamilton Depression Rating Scale scores rise significantly. At the same time there is greater activity of indoleamine 2,3-dioxygenase, with a resulting increase in plasma kynurenine concentrations. Compared to baseline values quinolinic acid concentrations increase significantly during therapy, reflecting an increased neurotoxic challenge. In addition, patients with higher scores in the Hamilton Depression Rating Scale at six and nine months after starting therapy show significantly higher levels of quinolinic acid concentration.

CONCLUSIONS

The increase of quinolinic acid during IFN-α therapy might contribute to depressive symptomatology through the neurotoxic challenge caused by quinolinic acid. Subsequently, our exploratory study results support the inflammatory hypothesis of depression. The awareness of relevant risk factors of IFN-α treatment-induced depression is essential to develop preventative treatment strategies.

Peripheral Administration of Tumor Necrosis Factor-Alpha Induces Neuroinflammation and Sickness but Not Depressive-Like Behavior in Mice

Clinical observations indicate that activation of the TNF-α system may contribute to the development of inflammation-associated depression. Here, we tested the hypothesis that systemic upregulation of TNF-α induces neuroinflammation and behavioral changes relevant to depression. We report that a single intraperitoneal injection of TNF-α in mice increased serum and brain levels of the proinflammatory mediators TNF-α, IL-6, and MCP-1, in a dose- and time-dependent manner, but not IL-1β. Protein levels of the anti-inflammatory cytokine IL-10 increased in serum but not in the brain. The transient release of immune molecules was followed by glial cell activation as indicated by increased astrocyte activation in bioluminescent Gfap-luc mice and elevated immunoreactivity against the microglial marker Iba1 in the dentate gyrus of TNF-α-challenged mice. Additionally, TNF-α-injected mice were evaluated in a panel of behavioral tests commonly used to study sickness and depressive-like behavior in rodents. Our behavioral data imply that systemic administration of TNF-α induces a strong sickness response characterized by reduced locomotor activity, decreased fluid intake, and body weight loss. Depressive-like behavior could not be separated from sickness at any of the time points studied. Together, these results demonstrate that peripheral TNF-α affects the central nervous system at a neuroimmune and behavioral level.

Glia in the cytokine-mediated onset of depression: fine tuning the immune response

Major depressive disorder (MDD) is a mood disorder of multifactorial origin affecting millions of people worldwide. The alarming estimated rates of prevalence and relapse make it a global public health concern. Moreover, the current setback of available antidepressants in the clinical setting is discouraging. Therefore, efforts to eradicate depression should be directed towards understanding the pathomechanisms involved in the hope of finding cost-effective treatment alternatives. The pathophysiology of MDD comprises the breakdown of different pathways, including the hypothalamus-pituitary-adrenal (HPA) axis, the glutamatergic system, and monoaminergic neurotransmission, affecting cognition and emotional behavior. Inflammatory cytokines have been postulated to be the possible link and culprit in the disruption of these systems. In addition, evidence from different studies suggests that impairment of glial functions appears to be a major contributor as well. Thus, the intricate role between glia, namely microglia and astrocytes, and the central nervous system's (CNSs) immune response is briefly discussed, highlighting the kynurenine pathway as a pivotal player. Moreover, evaluations of different treatment strategies targeting the inflammatory response are considered. The immuno-modulatory properties of vitamin D receptor (VDR) suggest that vitamin D is an attractive and plausible candidate in spite of controversial findings. Further research investigating the role of VDR in mood disorders is warranted.

Sex differences in depressive and socioemotional responses to an inflammatory challenge: implications for sex differences in depression

Substantial evidence demonstrates that inflammatory processes may underlie depression for a subset of patients, including work showing that healthy subjects exposed to an inflammatory challenge show increases in depressed mood and feelings of social disconnection. However, despite the fact that depression is two times as likely to occur in females than males, the vast majority of this work has been carried out in males. Thus, the objective of this study was to determine whether females (vs males) would show greater increases in proinflammatory cytokines, depressed mood, and social disconnection in response to an inflammatory challenge. One hundred and fifteen healthy participants (69 female) completed this double-blind, placebo-controlled, randomized clinical trial in which participants were randomly assigned to receive either a single infusion of low-dose endotoxin (derived from Escherichia coli; 0.8 ng/kg of body weight) or placebo (same volume of 0.9% saline). Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), depressed mood, and feelings of social disconnection were assessed hourly. Results showed that endotoxin (vs placebo) led to increases in proinflammatory cytokines (TNF-α, IL-6), depressed mood, and feelings of social disconnection. Females exposed to endotoxin showed greater increases in depressed mood and feelings of social disconnection. Furthermore, increases in TNF-α and IL-6 were correlated with increases in social disconnection for females but not for males. These sex differences in the relationships between inflammatory and socioemotional responses to an inflammatory challenge may be particularly important for understanding why females are two times as likely as males to develop depressive disorders.

Side effects of cytokines approved for therapy

Cytokines, currently known to be more than 130 in number, are small MW (<30 kDa) key signaling proteins that modulate cellular activities in immunity, infection, inflammation and malignancy. Key to understanding their function is recognition of their pleiotropism and often overlapping and functional redundancies. Classified here into 9 main families, most of the 20 approved cytokine preparations (18 different cytokines; 3 pegylated), all in recombinant human (rh) form, are grouped in the hematopoietic growth factor, interferon, platelet-derived growth factor (PDGF) and transforming growth factor β (TGFβ) families. In the hematopoietin family, approved cytokines are aldesleukin (rhIL-2), oprelvekin (rhIL-11), filgrastim and tbo-filgrastim (rhG-CSF), sargramostim (rhGM-CSF), metreleptin (rh-leptin) and the rh-erythropoietins, epoetin and darbepoietin alfa. Anakinra, a recombinant receptor antagonist for IL-1, is in the IL-1 family; recombinant interferons alfa-1, alfa-2, beta-1 and gamma-1 make up the interferon family; palifermin (rhKGF) and becaplermin (rhPDGF) are in the PDGF family; and rhBMP-2 and rhBMP-7 represent the TGFβ family. The main physicochemical features, FDA-approved indications, modes of action and side effects of these approved cytokines are presented. Underlying each adverse events profile is their pleiotropism, potency and capacity to release other cytokines producing cytokine 'cocktails'. Side effects, some serious, occur despite cytokines being endogenous proteins, and this therefore demands caution in attempts to introduce individual members into the clinic. This caution is reflected in the relatively small number of cytokines currently approved by regulatory agencies and by the fact that 14 of the FDA-approved preparations carry warnings, with 10 being black box warnings.

Applications of blood-based protein biomarker strategies in the study of psychiatric disorders

Major psychiatric disorders such as schizophrenia, major depressive and bipolar disorders are severe, chronic and debilitating, and are associated with high disease burden and healthcare costs. Currently, diagnoses of these disorders rely on interview-based assessments of subjective self-reported symptoms. Early diagnosis is difficult, misdiagnosis is a frequent occurrence and there are no objective tests that aid in the prediction of individual responses to treatment. Consequently, validated biomarkers are urgently needed to help address these unmet clinical needs. Historically, psychiatric disorders are viewed as brain disorders and consequently only a few researchers have as yet evaluated systemic changes in psychiatric patients. However, promising research has begun to challenge this concept and there is an increasing awareness that disease-related changes can be traced in the peripheral system which may even be involved in the precipitation of disease onset and course. Converging evidence from molecular profiling analysis of blood serum/plasma have revealed robust molecular changes in psychiatric patients, suggesting that these disorders may be detectable in other systems of the body such as the circulating blood. In this review, we discuss the current clinical needs in psychiatry, highlight the importance of biomarkers in the field, and review a representative selection of biomarker studies to highlight opportunities for the implementation of personalized medicine approaches in the field of psychiatry. It is anticipated that the implementation of validated biomarker tests will not only improve the diagnosis and more effective treatment of psychiatric patients, but also improve prognosis and disease outcome.

Quantifying serotonin transporters by PET with [11C]-DASB before and after interferon-α treatment

BACKGROUND

Interferon-α (IFN-α) therapy is frequently associated with disabling depression, fatigue, and related neuropsychiatric effects. Although depression in major depressive disorder is associated with low serotonin transporter binding, animal models suggest that IFN-associated mood effects are linked to increased presynaptic serotonin transporter binding. This study tested the hypotheses that IFN administration to human subjects increases presynaptic serotonin binding activity, and that this effect correlates with incident depression symptoms.

METHODS

Positron emission tomography (PET) scans using [11C]-DASB were obtained for nine hepatitis C patients before and after IFN-α treatment for 8 weeks. Serotonin transporter binding was estimated using the likelihood estimation in graphical analysis (LEGA) model and measured as the volume of distribution (VT) divided by the free fraction of ligand (fP). Depression was measured with the Structured Clinical Interview for DSM-IV Diagnosis (SCID) and the Hamilton Rating Scale for Depression (HAM-D).

RESULTS

Compared to pre-IFN treatment values, changes in serotonin transporter binding and depression symptoms were not significant. There was no correlation between changes in serotonin transporter binding and depression symptoms.

LIMITATIONS

The study is limited by small sample size, minimal effect on observed mood symptoms within the sample, and brief duration of follow-up.

CONCLUSION

These findings do not support the hypothesis of an IFN-induced change in serotonin transporter function as the cause of incident depressive symptoms in patients treated with IFN-α. Additional study of these possible relationships should be of longer duration and include more subjects with more pronounced changes in mood.