Interleukin-1beta and tumor necrosis factor-alpha in children with major depressive disorder or dysthymia

Cord serum cytokines at birth and children's trajectories of mood dysregulation symptoms from 3 to 8 years: The EDEN birth cohort

There is growing evidence that in utero imbalance immune activity plays a role in the development of neurodevelopmental and psychiatric disorders in children. Mood dysregulation (MD) is a debilitating transnosographic syndrome whose underlying pathophysiological mechanisms could be revealed by studying its biomarkers using the Research Domain Criteria (RDoC) model. Our aim was to study the association between the network of cord serum cytokines, and mood dysregulation trajectories in offsprings between 3 and 8 years of age. We used the data of a study nested in the French birth cohort EDEN that took place from 2003 to 2014 and followed mother-child dyads from the second trimester of pregnancy until the children were 8 years of age. The 2002 mother-child dyads were recruited from the general population through their pregnancy follow-up in two French university hospitals. 871 of them were included in the nested cohort and cord serum cytokine levels were measured at birth. Children's mood dysregulation symptoms were assessed with the Strengths and Difficulties Questionnaire Dysregulation Profile at the ages 3, 5 and 8 years in order to model their mood dysregulation trajectories. Out of the 871 participating dyads, 53% of the children were male. 2.1% of the children presented a high mood dysregulation trajectory whereas the others were considered as physiological variations. We found a significant negative association between TNF-α cord serum levels and a high mood dysregulation trajectory when considering confounding factors such as maternal depression during pregnancy (adjusted Odds Ratio (aOR) = 0.35, 95% Confidence Interval (CI) [0.18-0.67]). Immune imbalance at birth could play a role in the onset of mood dysregulation symptoms. Our findings throw new light on putative immune mechanisms implicated in the development of mood dysregulation and should lead to future animal and epidemiological studies.

Risks of anxiety disorders, depressive disorders, and sleep disorders in patients with dengue fever: A nationwide, population-based cohort study

BACKGROUND

Dengue virus (DENV) infection, a common mosquito-borne disease, has been linked to several mental disorders like depression and anxiety. However, the temporal risk of these disorders after DENV infection is not well studied.

METHODS

This population-based cohort study encompassed 45,334 recently lab-confirmed dengue patients in Taiwan spanning 2002 to 2015, matched at a 1:5 ratio with non-dengue individuals based on age, gender, and residence (n = 226,670). Employing subdistribution hazard regression analysis, we assessed the immediate (<3 months), intermediate (3-12 months), and prolonged (>12 months) risks of anxiety disorders, depressive disorders, and sleep disorders post DENV infection. Corrections for multiple comparisons were carried out using the Benjamini-Hochberg procedure.

RESULTS

A significant increase in depressive disorder risk across all timeframes post-infection was observed (<3 months [aSHR 1.90, 95% CI 1.20-2.99], 3-12 months [aSHR 1.68, 95% CI 1.32-2.14], and >12 months [aSHR 1.14, 95% CI 1.03-1.25]). Sleep disorder risk was higher only during 3-12 months (aSHR 1.55, 95% CI 1.18-2.04). No elevated anxiety disorder risk was found. Subgroup analysis of hospitalized dengue patients showed increased risk of anxiety disorders within 3 months (aSHR 2.14, 95% CI 1.19-3.85) and persistent risk of depressive disorders across all periods. Hospitalized dengue patients also had elevated sleep disorder risk within the first year.

CONCLUSION

Dengue patients exhibited significantly elevated risks of depressive disorders in both the short and long term. However, dengue's impact on sleep disorders and anxiety seems to be short-lived. Further research is essential to elucidate the underlying mechanisms.

Intricate role of sleep deprivation in modulating depression: focusing on BDNF, VEGF, serotonin, cortisol, and TNF-α

In this review article, we aimed to discuss intricate roles of SD in modulating depression in preclinical and clinical studies. Decades of research have shown the inconsistent effects of SD on depression, focusing on SD duration. However, inconsistent role of SD seems to be more complicated, and SD duration cannot be the only one factor. Regarding this issue, we chose some important factors involved in the effects of SD on cognitive functions and mood including brain-derived neurotrophic factor (BDNF), vascular endothelial growth factor (VEGF), serotonin, cortisol, and tumor necrosis factor-alpha (TNF-α). It was concluded that SD has a wide-range of inconsistent effects on BDNF, VEGF, serotonin, and cortisol levels. It was noted that BDNF diurnal rhythm is significantly involved in the modulatory role of SD in depression. Furthermore, the important role of VEGF in blood-brain barrier permeability which is involved in modulating depression was discussed. It was also noted that there is a negative correlation between cortisol and BDNF that modulates depression. Eventually, it was concluded that TNF-α regulates sleep/wake cycle and is involved in the vulnerability to cognitive and behavioral impairments following SD. TNF-α also increases the permeability of the blood-brain barrier which is accompanied by depressive behavior. In sum, it was suggested that future studies should focus on these mechanisms/factors to better investigate the reasons behind intricate roles of SD in modulating depression.

Cytokine alterations in pediatric internalizing disorders: Systematic review and exploratory multi-variate meta-analysis

Pediatric internalizing disorders are prevalent and characterized by a maladaptive cognitive, emotional response to a perceived stressor. The hypothesized effect of this response is observable changes in behavior mediated by homeostatic inflammatory cytokines. The aim of this study was to synthesize the literature and analyze the effect of cytokines on pediatric internalizing disorders. Influential moderating variables, including mean body mass index, fasting status at blood collection, participant sex, cytokine type, mean age, percentage of sample medicated, and diagnosis, were also assessed. A systematic literature search was performed in electronic databases (Medline, PubMed, and PsycINFO) from January 1, 1980 to June 15, 2022. Case-control studies of pediatric internalizing disorders, specifically anxiety and depression, were reviewed for their association with peripheral cytokine levels. Meta-analyses were performed using a random effects multi-variate model and effect sizes were calculated using Hedge's g for IL-2, CRP, IL-6, TNF-α, IL-1β, IFN-γ, and IL-10. Thirty-three studies were reviewed and 28 studies were included in the meta-analysis (n = 1322 cases and n = 3617 controls). Peripheral cytokine levels were elevated in pediatric internalizing disorders compared to controls (Hedge's g = 0.19, p < 0.001). In the moderator analyses, depression diagnosis (Hedge's g = 0.18, p = 0.009) and non-fasting blood collection (Hedge's g = 0.20, p = 0.006) were significant. The meta-analytic findings are limited by methodological variation between studies, high heterogeneity, and low statistical power. Despite this, the findings suggest that elevated peripheral cytokine levels may play a role in the etiology and/or symptom maintenance of pediatric internalizing disorders.

IL-10 (-819C/T), TNFA (-30G/A) and ENOS (-786T/C) Polymorphisms Modulating the Outcome Related to Mental Disorders in Crack Addicted Users

Background

Cocaine/crack use affects immune system molecules and development of mental disorders has been identified.

Objective

To investigate the relationship of polymorphisms in the TNFA (-308G/A), IL-10 (-819C/T) and ENOS (-786T/C) genes with mental disorders in cocaine and crack users.

Methods

A case-control study was carried out, which included 107 cocaine and crack users and 115 controls who never used healthy cocaine and crack. The SNPs in the TNFA (-308G/A), IL-10 (-819C/T) and ENOS (-786T/C) genes were genotyped by real time PCR.

Results

As for the individuals included in this study, the average age of 31.4 years (± 8.59). We identified that the G/A genotype to TNFA (-308) (OR = 0.24; p = 0.03) and the A allele (OR = 0.30; p = 0.03) were associated with reduced risk for dysthymic disorder. The T allele of the IL-10 (-819) polymorphism was associated with decreased risk of developing panic disorder (OR = 0.44; p = 0.01), while the C allele was correlated with an increased risk for alcohol dependence (OR = 1.97; p = 0.04), alcohol abuse (OR = 1.81; p = 0.04) and psychotic syndrome (OR = 2.23; p = 0.01). C/C genotype was correlated with increased chances of developing current psychotic syndrome (OR = 4.23; p = 0.01).

Conclusion

Our results suggest that genetic polymorphisms promote susceptibility or promote protection for clinical phenotypes of psychiatric comorbidities in cocaine and crack users and be considered as good prognostic markers.

Inflammatory Cytokines Changed in Patients With Depression Before and After Repetitive Transcranial Magnetic Stimulation Treatment

Studies have found that repetitive transcranial magnetic stimulation rTMS can produce antidepressant effects by affecting inflammatory cytokines in patients with depression, which plays a key role in the therapeutic mechanism of antidepressants. This study aimed to explore the changes in inflammatory cytokine levels in patients with depression after 4 weeks of rTMS treatment to determine the possible antidepressant mechanism of rTMS. This prospective, double-blind, pseudo-stimulus-controlled study was conducted, and a total of 57 patients with depression and 30 healthy controls were recruited. Patients were randomly divided into the active rTMS (n = 29) and sham rTMS groups (n = 28). The Hamilton Depression Scale was used to evaluate depressive symptoms and their severity. The serum levels of seven inflammatory cytokines were measured using enzyme-linked immunosorbent assay. Inflammatory cytokines include high-sensitivity C-reactive protein (CRP-hc); tumor necrosis factor (TNF-α); interferon (IFN-γ); interleukin-2 (IL-2); interleukin-4 (IL-4); interleukin-6 (IL-6); and interleukin-8 (IL-8). At baseline, TNF-α (F = 36.699, p < 0.001), IFN-γ (F = 8.907, p < 0.001), IL-4 (F = 66.256, p < 0.001), and IL-2 (F = 9.162, p < 0.001) levels in the depression group were significantly different from those of healthy controls. In the self-control analysis of the active rTMS group, the levels of IL-2 and CRP-hc increased significantly after 2 and 12 weeks of treatment. In the sham-rTMS group, IFN-γ increased after 2 and 12 weeks of treatment. Our results revealed that the changes in inflammatory cytokines after rTMS treatment showed different patterns compared to the sham group, suggesting that the antidepressant effect of rTMS may be related to changes in inflammatory cytokines.

Linking childhood trauma and cytokine levels in depressed adolescents

BACKGROUND

Evidence supports raised circulating levels of inflammatory mediators, such as interleukin-6 (IL-6) and tumor necrosis factor (TNFα), among clinically depressed adults, although preliminary findings in adolescents are mixed. Independently, meta-analyses identify correlations between childhood trauma and elevated cytokine levels in adulthood. Here, we examine the possible role of individual differences in exposure to childhood trauma in contributing to variability in cytokine levels in depressed adolescents.

METHODS

52 depressed adolescents and 20 healthy adolescents completed measures of childhood trauma and provided blood for the assessment of plasma IL-6 and TNFα. Cross-sectional associations of childhood trauma and cytokine measures were assessed in both depressed and healthy adolescents, along with exploratory analysis of childhood trauma subtypes. Longitudinal relationships between childhood trauma and cytokine measures were also studied in an exploratory fashion within a subset of depressed participants (n = 36).

RESULTS

Higher childhood trauma (particularly emotional abuse) was positively associated with TNFα in depressed adolescents. Childhood trauma was not linked to longitudinal changes in cytokine levels.

DISCUSSION

In depressed adolescents, childhood trauma may relate to higher levels of the proinflammatory cytokine TNFα and contribute to heterogeneity in cytokine elevation among depressed adolescents. Such findings may ultimately help guide more effective individualized treatments for adolescents with depression.

Increased telomerase activity in major depressive disorder with melancholic features: Possible role of pro-inflammatory cytokines and the brain-derived neurotrophic factor

The biological mechanisms responsible for depression symptoms are not yet understood. For this reason, it is important to reveal the etiopathogenetic mechanisms in this disease. This study aims to compare the levels of pro-inflammatory cytokines, Brain-Derived Neurotrophic Factor (BDNF), and telomerase activity in patients with major depressive disorder (MDD) and healthy controls. Plasma BDNF, interleukin-6 (IL-6), IL-1beta, and Tumor Necrosis Factor-alpha (TNF-alpha) levels, and telomerase activity were measured in 39 patients with major depression and 39 healthy controls matched with patients in terms of age, gender, and education year. Plasma concentration of BDNF, IL-6 levels, and telomerase activity was significantly different between patients with MDD and healthy controls. Correlation analysis showed a positive trend between plasma BDNF levels and plasma IL-6 levels in patients with MDD with melancholic features. Furthermore, the path analysis results showed that the telomerase activity was indirectly affected by gender, IL-1β, IL-6, BDNF, and BMI, via the severity of depression and anxiety and MDD status as the mediators. Further studies are needed to examine the molecular mechanism of the telomerase activity and the role of BDNF and pro-inflammatory cytokines in the telomerase activation in MDD.

Immunological Effects of an Add-On Physical Exercise Therapy in Depressed Adolescents and Its Interplay with Depression Severity

BACKGROUND

Pro-inflammatory cytokines (PICs) have gained attention in the pathophysiology and treatment of depressive disorders. At the same time, the therapeutic effect of physical activity seems to work via immunomodulatory pathways. The interventional study "Mood Vibes" analyzed the influence of exercise on depression severity (primary endpoint) in depressive adolescents; the influence of PICs on the clinical outcome was analyzed as a secondary endpoint.

METHODS

Clinically diagnosed depressed adolescents (N = 64; 28.1% male; mean age = 15.9; mean BMI = 24.6) were included and participated either in Whole Body Vibration (WBV) (n = 21) or bicycle ergometer training (n = 20) in addition to treatment-as-usual (TAU). Patients in the control treatment group received TAU only (n = 23). The PICs (interleukin-6-IL-6 and tumor necrosis factor-α-TNF-α) were analyzed before intervention, after 6 weeks of training (t1), and 8 weeks post-intervention (t2). The effects of the treatment on depression severity were rated by self-rating "Depression Inventory for Children and Adolescents" (DIKJ).

RESULTS

Basal IL-6 decreased in all groups from t0 to t1, but it increased again in WBV and controls at t2. TNF-α diminished in ergometer and controls from baseline to t1. PIC levels showed no correlation with depression severity at baseline. The influence on DIKJ scores over time was significant for IL-6 in the WBV group (p = 0.008). Sex had an impact on TNF-α (p < 0.001), with higher concentrations in male patients. Higher body mass index was associated with higher IL-6 concentrations over all measurement points (p < 0.001).

CONCLUSIONS

The positive effects of an intensive add-on exercise therapy on adolescent depression seem to be partly influenced by immunomodulation. A small sample size and non-randomized controls are limitations of this study.

Long-term evaluation of temporomandibular disorders in association with cytokine and autoantibody status in young women

Temporomandibular disorders (TMD) is a chronic pain disease affecting 4-60% of general population. Its suggested etiology includes mechanical overloading to related structures, psychosocial factors, and genetic vulnerability. However, its pathogenesis is yet to be fully understood, especially in cases with a higher level of pain and more associated comorbidities. Recently chronic systemic inflammation and possible autoimmunity has been indicated in several pain conditions as the underlying mechanism of chronicity but this aspect has not been rigorously investigated in TMD. This article focuses on analyzing the levels of cytokines, chemokines, autoantibodies and nonspecific inflammatory markers and comparing their levels according to pain severity and duration in 66 female TMD patients in their 20 s and investigating their association with clinical indices of TMD and comorbidities. The high pain disability group showed decreased range of jaw function and more pain on palpation of capsule areas compared to the low pain disability group. Comorbidities such as anxiety and sleep disturbance were also significantly more prevalent. The level of IL-8 and IgG were significantly higher in the high pain disability group. IL-2, -8, -13, IFN- γ, RANTES, PGE2, and thrombopoietin levels showed a significant effect on indices reflecting jaw function, generalized pain intensity, and health related quality of life. Such results imply that longer pain duration and higher pain intensity is associated with higher levels of systemic inflammation suggesting the possible role of immunologic disturbance as an underlying factor of chronic TMD pain and warranting further investigation for its consideration in diagnosis and treatment.

Personalized Medicine Using Neuroimmunological Biomarkers in Depressive Disorders

Major depressive disorder (MDD) is associated with increased suicidal risk and reduced productivity at work. Neuroimmunology, the study of the immune system and nervous system, provides further insight into the pathogenesis and outcome of MDD. Cytokines are the main modulators of neuroimmunology, and their levels are somewhat entangled in depressive disorders as they affect depressive symptoms and are affected by antidepressant treatment. The use of cytokine-derived medication as a treatment option for MDD is currently a topic of interest. Although not very promising, cytokines are also considered as possible prognostic or diagnostic markers for depression. The machine learning approach is a powerful tool for pattern recognition and has been used in psychiatry for finding useful patterns in data that have translational meaning and can be incorporated in daily clinical practice. This review focuses on the current knowledge of neuroimmunology and depression and the possible use of machine learning to widen our understanding of the topic.

Depression and inflammation among children and adolescents: A meta-analysis

BACKGROUND

Increasing evidence suggests that youth with Major Depressive Disorder (MDD) exhibit early indicators of cardiovascular disease. A leading hypothesized mechanism of this association is via inflammatory pathways, however, results examining this direct association are mixed. Our objective was to synthesize and quantify observational studies examining the association of depression and inflammation among children and adolescents.

METHODS

Electronic searches were conducted in MEDLINE, Embase, PsycINFO, and Scopus, yielding 2,757 non-duplicate records from 1946 to 2019. The included studies measured depression or depressive symptoms and examined its association with inflammation in participants younger than 18 years. All relevant articles were reviewed and data extracted by two independent coders. Estimates were examined by using random-effects meta-analysis.

RESULTS

Twenty-two studies (20,791 participants) were included. Significant associations were observed between concurrent depression and CRP (n = 7; r = 0.12; 95% confidence interval [CI] = 0.04 to 0.19), and IL-6 (n = 7; r = 0.17; 95% CI= 0.10 to 0.24). Longitudinal analyses revealed that depression is a significant predictor of IL-6 (n = 3; r = 0.29; 95% CI= 0.04 to 0.50) and conversely, that inflammation (measured by CRP or IL-6) predicts future depression (n = 4; r = 0.04; 95% CI= 0.00 to 0.08).

LIMITATIONS

Results are limited by the small number of studies preventing examination of some moderator variables. Findings are correlational, not causal.

CONCLUSION

Depression is positively associated with concurrent and future inflammation among children and adolescents. Results suggest that bidirectional associations may exist between depression and a pro-inflammatory state.

Association of Anxiety With Pain and Disability but Not With Increased Measures of Inflammation in Adolescent Patients With Juvenile Idiopathic Arthritis

Objective

To explore whether anxiety and depression are associated with clinical measures of disease for adolescent patients with juvenile idiopathic arthritis (JIA) and whether anxiety and depression are associated with increased peripheral proinflammatory cytokine levels in adolescent patients with JIA and in healthy adolescent controls.

Methods

A total of 136 patients with JIA and 88 healthy controls ages 13–18 years completed questionnaires on anxiety and depressive symptoms. For patients with JIA, pain, disability, physician global assessment (using a visual analog scale [VAS]), and number of joints with active inflammation (active joint count) were recorded. In a subsample, we assessed lipopolysaccharide‐stimulated interleukin 6 (IL‐6) production from peripheral blood mononuclear cells, serum IL‐6, cortisol, and C‐reactive protein levels. Data were analyzed by linear regression analysis.

Results

Levels of anxiety and depressive symptoms in patients with JIA were not significantly different than those in healthy controls. For patients with JIA, anxiety was significantly associated with disability (β = 0.009, P = 0.002), pain (β = 0.029, P = 0.011), and physician global assessment VAS (β = 0.019, P = 0.012), but not with active joint count (β = 0.014, P = 0.120). Anxiety was not associated with any laboratory measures of inflammation for JIA patients. These relationships were also true for depressive symptoms. For healthy controls, there was a trend toward an association of anxiety (but not depressive symptoms) with stimulated IL‐6 (β = 0.004, P = 0.052).

Conclusion

Adolescent patients with JIA experience equivalent levels of anxiety and depressive symptoms as healthy adolescents. For adolescent patients with JIA, anxiety and depressive symptoms are associated with pain, disability, and physician global assessment VAS, but not with inflammation.

Prospective study on cytokine levels in medication-naïve adolescents with first-episode major depressive disorder

BACKGROUND

Evidence suggests that depression is correlated with immune-inflammatory responses, and efforts have been made to identify the relationships between depression and inflammatory markers. This study investigated the level of cytokines before and after treatment for major depressive disorder (MDD) in medication-naïve adolescents with first-episode MDD and compared them with the levels in healthy adolescents. The relationship between cytokine levels and the severity of depressive symptoms was also examined.

METHODS

Twenty-five adolescents with MDD and 25 healthy controls aged 13 to 18 years were included in the study. Blood samples were obtained, and depression severity was assessed twice in the MDD group before and after treatment and once in the healthy group.

RESULTS

When compared with healthy controls, adolescents with MDD had lower levels of interleukin 2 (IL-2), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α) and IL-10 before treatment and higher levels of IL-2, IFN-γ, and IL-10 after treatment. In addition, the IFN-γ levels correlated with depressive severity scores in both the Children's Depression Inventory (CDI) and Hamilton Depression Rating Scale (HDRS). The IL-10 level correlated with depressive severity only on the HDRS.

LIMITATIONS

The sample size was small, and the 12-week follow-up time after treatment was relatively short.

CONCLUSION

IL-2, IFN-γ, TNF-α, and IL-10 levels in medication-naïve adolescents with first-episode MDD differed from those in healthy controls. The levels of IL-2, IFN-γ, and IL-10 were altered after antidepressant treatment. Further, the IFN-γ and IL-10 levels correlated with the severity of depressive symptoms.

Tumor Necrosis Factor-α Variations in Patients With Major Depressive Disorder Before and After Antidepressant Treatment

Tumor necrosis factor-α (TNF-α) had been identified as a key pro-inflammatory cytokine in the pathophysiology of major depressive disorder (MDD) and the mechanism of antidepressant treatment. The primary aim of the present study was to examine the serum TNF-α levels in Chinese inpatients with MDD during the acute phase and to explore the changes in TNF-α levels after effective clinical treatment. Fifty-seven consecutive inpatients with MDD and 30 healthy controls were recruited. The serum TNF-α levels were detected using ELISA. Symptoms of depression were evaluated using the 24-item Hamilton Rating Scale for Depression (HAM-D-24). TNF-α levels and HAM-D-24 scores were assessed at baseline and after 2 and 12 weeks of follow-up. The serum TNF-α levels were higher in the MDD group than in the control group. After 2 and 12 weeks of antidepressant treatment, there were significant improvements in the patients' symptoms and significant decreases in the TNF-α levels. The baseline TNF-α levels significantly correlated with the decreased HAM-D-24 scores, particularly for the depressive symptoms of anxiety/somatization and weight loss. The present findings indicate that depression is accompanied by activation of TNF-α, which also has a predictive value for the antidepressant treatment response in patients with MDD.

Depressive and Anxiety Symptoms among Pediatric In-Patients with Dengue Fever: A Case-Control Study

BACKGROUND

Psychiatric symptoms have been reported in adult patients with dengue fever (DF); however, information on pediatric patients remains inadequate. We sought to identify the prevalence and predictors of depressive and anxiety symptoms and identify other psychiatric symptoms among pediatric patients with DF. This case-control study involved pediatric in-patients (n = 225) who had clinical or serologic-confirmed DF and healthy school-based controls (n = 260). Participants completed the Revised Child Anxiety and Depression Scale (RCADS).

RESULTS

The prevalence of depressive (13.3%) and anxiety (34.2%) symptoms among pediatric patients with DF was significantly (p < 0.001) higher than that among controls (3.5% and 16.2%, respectively). Multiple linear regression analysis found that age, family history of DF, ≤2 days of hospitalization, myalgia, and arthralgia were predictors of increased depressive and anxiety symptoms among the patients. Further, 26.7% of pediatric patients reported irritability, agitation, visual hallucinations, and aggressiveness.

CONCLUSION

Pediatric patients present depressive and anxiety symptoms whose levels were associated with social and clinical factors. However, whether these symptoms are present only during the infection or may still persist after recovery or are brought by children's adverse reactions to hospitalization are unknown, and thus, further studies are needed.

Inflammatory biomarkers and brain health indicators in children with overweight and obesity: The ActiveBrains project

INTRODUCTION

Chronic inflammation plays an important role on the pathogenesis of several cardiovascular and metabolic diseases, as well as on brain function and behaviour. The aim of the present study was to examine the associations between inflammatory biomarkers and a wide range of brain health indicators (i.e., academic performance, executive function, behavioural and emotional functioning, and brain volume) in children with overweight/obesity.

METHODS

A total of 107 children (10.0 ± 1.1 years, 41% girls) from the ActiveBrains project were included in the analysis. Five inflammatory biomarkers were analysed in plasma: white blood cell (WBC) count, interleukin-6 (IL-6), interleukin-1β, tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP). Academic performance was assessed by Woodcock-Muñoz Tests of Achievement. Executive function was assessed through the Design Fluency Test for cognitive flexibility, the Stroop test for cognitive inhibition, and the Delayed Non-Match-to-Sample task for working memory. Behavioural and emotional functioning was evaluated through the Behavior Assessment System for Children (BASC) questionnaire. Total and regional brain volume was assessed by magnetic resonance imaging.

RESULTS

IL-6 was inversely associated with adaptive skills (β = -0.228; p = 0.030), while TNF-α was related to mathematics (β = -0.198; p = 0.034). In addition, CRP was positively associated with externalizing (β = 0.246; p = 0.046) and internalizing problems (β = 0.234; p = 0.039), as well as the behavioural symptoms index (β = 0.236; p = 0.047). However, these significant associations disappeared after multiple comparisons correction. Inflammatory biomarkers were not associated with executive function and total brain volumes. Regarding regional brain analyses, WBC was positively associated with gray matter volume in the left middle temporal gyrus (β = 0.387; p < 0.001, k = 44), and CRP was positively associated with gray matter volume in the right superior temporal gyrus (β = 0.439; p < 0.001, k = 29). Additionally, when adjusting by total brain volume, CRP was positively associated with gray matter volume in the right supplementary motor cortex (β = 0.453; p < 0.001, k = 51). Moreover, both, IL-6 (β = 0.366; p < 0.001, k = 81) and TNF-α (β = 0.368; p < 0.001, k = 62) were positively associated with white matter volume around the right inferior frontal gyrus pars opercularis, while CRP was inversely associated with white matter volume around the left superior frontal gyrus (β = -0.482; p < 0.001, k = 82). After adjusting by total brain volume, CRP was also inversely associated with white matter volume in 3 additional clusters (β ranging from -0.473 to -0.404; p < 0.001, k = 87).

CONCLUSIONS

Inflammation was slightly associated with brain health (i.e., academic performance, behavioural and emotional functioning and regional brain volume) in children with overweight or obesity. Further larger longitudinal and interventional studies are warranted to elucidate the short-term and long-term effect of systemic low-grade inflammation on children's brain health.

Depressive symptoms and immune transcriptional profiles in late adolescents

BACKGROUND

Rates of depression increase and peak during late adolescence and alterations in immune processes are thought to be both a risk factor and outcome of depression. However, few studies have examined depression-immune dynamics among adolescents. Using a functional genomics approach, the current study examined whether depressive symptoms were associated with activation of a gene expression profile, characterized by upregulated expression of pro-inflammatory-related genes and downregulated expression of antiviral-related genes in a sample of older adolescents (M_age = 18.37, SD = 0.51).

METHOD

Participants (n = 87) reported on their depressive symptoms during the past week using the CES-D, and provided blood samples for genome-wide transcriptional profiling of mRNA.

RESULTS

Adolescents with clinically-significant levels of depressive symptoms (CES-D ≥ 16) exhibited upregulated expression of inflammation-related genes and downregulated expression of antiviral-related genes compared to their peers with lower levels of depressive symptoms (CES-D < 16). Bioinformatics analyses suggested that this pattern of differential gene expression was mediated by greater activity of the pro-inflammatory transcription factor, nuclear factor-kappa B (NF-κB), and reduced activity of glucocorticoid receptors (GRs) and interferon response factors (IRFs). Additional analyses implicated monocytes, B cells, and dendritic cells as primary cellular sources of the observed gene expression patterns associated with depressive symptoms.

CONCLUSION

Results are consistent with past work demonstrating links between depression and altered immunity. They provide a molecular basis for these associations and suggest that the underlying molecular signature may emerge as early as late adolescence when rates of depression tend to increase.

Interplay between pro-inflammatory cytokines, childhood trauma, and executive function in depressed adolescents

BACKGROUND

Pro-inflammatory cytokines have been linked to depression, early childhood trauma, and impairment in executive function in adults. Whether these links are present during adolescence, a time when vulnerability to depression is heightened, a point more proximal to childhood trauma, and a critical period of brain development, is not well understood.

METHOD

Serum levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor alpha (TNF-α) were measured in 70 adolescents aged 12-17, including 40 with a DSM-IV depressive disorder (DEP), a sub-set (n = 22) of whom reported a history of childhood trauma (DEP-T), and 30 healthy controls (HCs). Participants completed performance-based (Parametric Go/No-Go Task) and observer-rated (Behavior Rating Inventory of Executive Function) measures of executive function. Procedures were conducted at a subspecialty clinic (Dec 2015-June 2017).

RESULTS

IL-6 was elevated in DEP and DEP-T adolescents compared to controls (p = .014) and TNF-α was elevated in DEP participants only (p = .040) compared to controls, whereas no group differences were found in IL-1β (p = .829). Additionally, DEP-T participants demonstrated relative deficits in performance-based (p = .044) and observer-rated inhibitory control (p = .049) compared to controls. Across the whole sample, TNF-α was associated with performance-based (r = -0.25, p = .039) and observer-rated (r = 0.32, p = .009) inhibitory control deficits. In subgroup analyses, TNF-α was associated with increased observer-rated inhibitory deficits in DEP, and at the trend level, with reduced inhibitory control performance in DEP-T.

CONCLUSIONS

The current results suggest that inflammation may be a marker of disease processes in adolescent depression. Though longitudinal studies are needed, depressed adolescents with childhood trauma exposure appear to constitute a uniquely vulnerable group in terms of objective risk for executive dysfunction. Immune dysregulation may partly contribute to this risk.

Inflammatory Cytokines in Children and Adolescents with Depressive Disorders: A Systematic Review and Meta-Analysis

Objective: Meta-analytic evidence shows alterations of peripheral inflammatory cytokines in adults with depressive disorders. By contrast, no evidence synthesis on alterations of peripheral inflammatory cytokines in children/adolescents with depressive disorders is available to date. To fill this gap, we conducted a systematic review and meta-analysis of case-control studies comparing serum cytokine levels in children/adolescents with depressive disorders and healthy controls. Methods: Based on a preregistered protocol (PROSPERO-CRD42018095418), we searched PubMed, Ovid, and Web of Knowledge from inception through July 21, 2018, with no language restrictions, and contacted study authors for unpublished data/information. Random-effects model was used to compute effect size for each cytokine. The Newcastle-Ottawa Scale was used to asses study bias. Results: From a pool of 4231 nonduplicate, potentially relevant references, 8 studies were retained for the qualitative synthesis and 5 for the meta-analysis. TNF-α was higher in participants with depressive disorders versus controls, falling short of statistical significance. Conclusions: Overall, due to the small number of studies, in contrast to the literature in adults, further evidence is needed to confirm possible inflammatory alterations associated with depression in youth.

Environmental Exposures and Neuropsychiatric Disorders: What Role Does the Gut-Immune-Brain Axis Play?

PURPOSE OF REVIEW

Evidence is growing that environmental exposures-including xenobiotics as well as microbes-play a role in the pathogenesis of many neuropsychiatric disorders. Underlying mechanisms are likely to be complex, involving the developmentally sensitive interplay of genetic/epigenetic, detoxification, and immune factors. Here, we review evidence supporting a role for environmental factors and disrupted gut-immune-brain axis function in some neuropsychiatric conditions.

RECENT FINDINGS

Studies suggesting the involvement of an altered microbiome in triggering CNS-directed autoimmunity and neuropsychiatric disturbances are presented as an intriguing example of the varied mechanisms by which environmentally induced gut-immune-brain axis dysfunction may contribute to adverse brain outcomes. The gut-immune-brain axis is a burgeoning frontier for investigation of neuropsychiatric illness. Future translational research to define individual responses to exogenous exposures in terms of microbiome-dependent skew of the metabolome, immunity, and brain function may serve as a lens for illumination of pathways involved in the development of CNS disease and fuel discovery of novel interventions.

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

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

Increased neutrophil-lymphocyte ratios in depressive adolescents is correlated with the severity of depression

We aimed to investigate the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescents with major depression. Sixty-seven adolescents and 121 healthy controls were enrolled in the study. The diagnosis was made by using both the Kiddie and Young Adult Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version and the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition. The severity of depressive symptoms was evaluated using the Beck depression inventory (BDI). The neutrophil-lymphocyte ratios of the adolescents with depression were significantly higher than those of the control group, even after adjusting for age, sex, BMI, and BDI scores, whereas there was no significant difference in platelet-lymphocyte ratios. A positive correlation between the severity of depression and neutrophil-lymphocyte ratios and platelet-lymphocyte ratios were determined in the case group. The results of this study may promote the hypothesis that inflammation plays an important role in the etiology of major depression in adolescents.

Depressive symptoms, pain and disability for adolescent patients with juvenile idiopathic arthritis: results from the Childhood Arthritis Prospective Study

Objectives

To determine if depressive symptoms assessed near diagnosis associate with future measures of pain, disability and disease for adolescent patients diagnosed with JIA.

Methods

Data were analysed from JIA patients aged 11–16 years recruited to the Childhood Arthritis Prospective Study, a UK-based inception cohort of childhood-onset arthritis. Depressive symptoms (using the Mood and Feelings Questionnaire; MFQ), active and limited joint count, disability score (Childhood Health Assessment Questionnaire), pain visual analogue scale and patient’s general evaluation visual analogue scale were collected. Associations between baseline measures (first visit to paediatric rheumatologist) were analysed using multiple linear regression. Linear mixed-effect models for change in the clinical measures of disease over 48 months were estimated including MFQ as an explanatory variable.

Results

Data from 102 patients were analysed. At baseline, median (IQR) age was 13.2 years (11.9–14.2 years) and 14.7% scored over the MFQ cut-off for major depressive disorder. At baseline, depressive symptoms significantly associated with all clinical measures of disease (P ⩽ 0.01). High baseline depressive symptoms scores predicted worse pain (P ⩽ 0.005) and disability (P ⩽ 0.001) 12 months later but not active and limited joint counts.

Conclusions

Adolescent patients with JIA and depressive symptoms had more active joints, pain and disability at the time of their first specialist appointment. The associations between baseline depression and both pain and disability continued for at least one year, however, this was not the case for active joint count.

Mechanisms underlying the association between insomnia, anxiety, and depression in adolescence: Implications for behavioral sleep interventions

There is robust evidence of an association between insomnia, anxiety, and depression in adolescence. The aim of this review is to describe and synthesize potential mechanisms underlying this association and explore implications for the design of adolescent behavioral sleep interventions. Specifically, we examine whether insomnia symptoms are a mechanism for the development of internalizing symptoms in adolescence and whether sleep interventions are an effective treatment for both insomnia and internalizing symptoms in adolescence because they target the shared mechanisms underlying these disorders. Research using different methodologies points to the role of sequential, parallel, and interacting mechanisms. In this paper, we review a wide range of relevant biological (i.e., polymorphisms and dysregulation in serotonin, dopamine, and circadian clock genes; alterations in corticolimbic and mesolimbic brain circuits; cortisol reactivity to stress; inflammatory cytokine dysregulation; biased memory consolidation; changes in sleep architecture), psychological (i.e., cognitive inflexibility, interpretational biases, judgment biases, negative attribution styles, worry, rumination, biased attention to threat, dysfunctional beliefs and attitudes about sleep, misperception of sleep deficit), and social mechanisms (i.e., reduced and impaired social interactions, unhelpful parenting behaviors, family stress) and propose an integrative multilevel model of how these phenomena may interact to increase vulnerability to both insomnia and internalizing disorders. Several 'biopsychosocial' mechanisms hold promise as viable treatment targets for adolescent behavioral sleep interventions, which may reduce both insomnia and internalizing symptoms.

Gene expression in blood of children and adolescents: Mediation between childhood maltreatment and major depressive disorder

Investigating major depressive disorder (MDD) in childhood and adolescence can help reveal the relative contributions of genetic and environmental factors to MDD, since early stages of disease have less influence of illness exposure. Thus, we investigated the mRNA expression of 12 genes related to the hypothalamic-pituitary-adrenal (HPA) axis, inflammation, neurodevelopment and neurotransmission in the blood of children and adolescents with MDD and tested whether a history of childhood maltreatment (CM) affects MDD through gene expression. Whole-blood mRNA levels of 12 genes were compared among 20 children and adolescents with MDD diagnosis (MDD group), 49 participants without MDD diagnosis but with high levels of depressive symptoms (DS group), and 61 healthy controls (HC group). The differentially expressed genes were inserted in a mediation model in which CM, MDD, and gene expression were, respectively, the independent variable, outcome, and intermediary variable. NR3C1, TNF, TNFR1 and IL1B were expressed at significantly lower levels in the MDD group than in the other groups. CM history did not exert a significant direct effect on MDD. However, an indirect effect of the aggregate expression of the 4 genes mediated the relationship between CM and MDD. In the largest study investigating gene expression in children with MDD, we demonstrated that NR3C1, TNF, TNFR1 and IL1B expression levels are related to MDD and conjunctly mediate the effect of CM history on the risk of developing MDD. This supports a role of glucocorticoids and inflammation as potential effectors of environmental stress in MDD.

Pro-Inflammatory Cytokines in Psychiatric Disorders in Children and Adolescents: A Review

Cytokines are a large group of small proteins which play a significant role in cell signaling and regulate a variety of processes in organisms, including proliferation and differentiation of many cells, mediation in defense reactions and regulation of hematopoiesis. Cytokines can be divided into those with pro- and those with anti-inflammatory properties. In the group of pro-inflammatory cytokines the most important are: IL-1 beta, IL-6, TNF-alpha, and IFN-gamma. Pro-inflammatory cytokines might be involved in the pathophysiology of many psychiatric conditions in adults, but their role in children and adolescents is less clear. The aim of this article is to demonstrate the patterns of pro-inflammatory cytokines in children and adolescents.

Changes in cytokine and chemokine expression distinguish dysthymic disorder from major depression and healthy controls

An important area of uncertainty is the inflammatory degree to which depression occurring as part of dysthymic disorder may differ from major depression. Using a 27-plex cytokine assay, we analyzed the serum of 12 patients with dysthymic disorder, 12 with major depression, and an age-, sex-, and body mass index-matched control group of 20 healthy volunteers. We observed that patients with dysthymic disorder exhibited aberrant cytokine and chemokine expression compared with healthy controls and patients with major depression. The levels of interferon-γ-induced protein 10 highly predicted dysthymic disorder. Network analyses revealed that in patients with dysthymic disorder, the vertices were more sparsely connected and adopted a more hub-like architecture, and the connections from neighboring vertices of interleukin 2 and eotaxin-1 increased. After treatment with the same antidepressant, there was no difference between dysthymic disorder and major depression regarding any of the cytokines or chemokines analyzed. For dysthymic disorder, changes in the levels of interferon-γ-induced protein 10 and macrophage inflammatory protein-1α correlated with depression improvement. The findings suggest that the cytokine milieu in dysthymic disorder differs either at the level of individual expression or in network patterns. Moreover, chemokines play an important role in driving the pathophysiology of dysthymic disorder.

Pro-inflammatory Cytokines in Psychiatric Disorders in Children and Adolescents: A Review

Cytokines are a large group of small proteins which play a significant role in cell signaling and regulate a variety of processes in organisms, including proliferation and differentiation of many cells, mediation in defense reactions and regulation of hematopoiesis. Cytokines can be divided into those with pro- and those with anti-inflammatory properties. In the group of pro-inflammatory cytokines the most important are: IL-1 beta, IL-6, TNF-alpha, and IFN-gamma. Pro-inflammatory cytokines might be involved in the pathophysiology of many psychiatric conditions in adults, but their role in children and adolescents is less clear. The aim of this article is to demonstrate the patterns of pro-inflammatory cytokines in children and adolescents.

Serum Cytokine Levels in Major Depressive Disorder and Its Role in Antidepressant Response

OBJECTIVE

Cytokines have been reported to have key roles in major depressive disorder (MDD). However, much less is known about cytokines in MDD and antidepressant treatment due to the diversity of cytokines and the heterogeneity of depression. We investigated the levels of cytokines in patients with MDD compared with healthy subjects and their associations with antidepressant response.

METHODS

We investigated the changes of several cytokines (eotaxin, sCD40L, IL-8, MCP-1alpha, TNF-alpha, INF-gamma and MIP-1alpha) by Luminex assay in 66 patients with MDD and 22 healthy controls. The antidepressant response was assessed by 17-item Hamilton Rating Scale for Depression.

RESULTS

We found the levels of sCD40L (p=0.001), IL-8 (p=0.004) and MCP-1 (p=0.03) of healthy controls were significantly higher than those of depressive patients. However, the level of eotaxin and TNF-alpha were not associated with MDD. In addition, we found the level of MCP-1 was significantly changed after antidepressant treatment (p=0.01).

CONCLUSION

These findings suggest the roles of cytokines in MDD are complex, and could vary according to the individual characteristics of each patient. Further studies regarding the relationship between cytokines and MDD will be required.

Inflammatory cytokines and nuclear factor-kappa B activation in adolescents with bipolar and major depressive disorders

Adults with bipolar disorder (BD) and major depressive disorder (MDD) have higher circulating levels of proinflammatory cytokines than healthy controls. However, it is not known whether pediatric-onset patients with BD or MDD show increases in levels of inflammation or activation of nuclear factor kappa B (NF-κB), a key transcription factor in inflammatory signaling. Circulating levels of inflammatory cytokines, as well as spontaneous and stimulated levels of activated NF-κB in total peripheral blood mononuclear cells, monocytes and lymphocytes were measured in adolescents with BD (n=18), MDD (n=13), or no psychiatric history (n=20). Participants had a range of mood symptoms at time of testing. Adolescents with BD had significantly higher spontaneous levels of NF-κB in peripheral blood mononuclear cells, monocyte and lymphocyte populations, and higher plasma levels of IL-1β than healthy controls. Following stimulation with recombinant human TNF-α, participants with BD and MDD both had greater increases in NF-κB in monocytes than controls. Further, greater stimulated increases of NF-κB in monocytes were associated with the current severity of depressive symptoms. The results are limited by the small sample and cross-sectional design. Interventions that target early immunological dysregulation should be examined in relation to long-term outcomes in youth with bipolar and depressive disorders.

CLINICAL TRIAL REGISTRATION INFORMATION

Early Intervention for Youth at Risk for Bipolar Disorder, https://clinicaltrials.gov/ct2/show/NCT01483391.

The Role of C-Reactive Protein in Mood Disorders

Recently, a possible relationship between C-Reactive Protein (CRP), a marker of underlying low-grade inflammation, and mood disorders has been proposed by some researchers. The aim of this review is to elucidate the current facts and views about CRP in mood disorders such as Depressive and Bipolar Disorders. Several studies have examined the relationship between affective disorders and CRP, but the majority of the studies in literature have been limited by retrospective, case-controlled study design, and very few studies have examined the relationship between depression and CRP in large study samples. In conclusion, the role of CRP in mood disorders is, to date, intriguing but somewhat unclear. Further prospective studies are needed to introduce the CRP in clinical settings as a marker of affective states and suicidability.

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

To clarify findings of elevated cytokine levels in major depression (MD), this study aimed to investigate the relationship between serum levels of cytokines, symptoms of MD and antidepressant treatment outcome. At baseline (T0) and 4 weeks following initiation of antidepressant treatment (T1), levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, granulocyte-macrophage-colony-stimulating-factor (GM-CSF), CRP and depression ratings HAMD-17 and BDI-II were assessed in 30 patients with MD and 30 age-and sex-matched controls. At T0, in the patient group, cytokines, but not CRP, negatively correlated with individual BDI-II-items, factors and severities and showed both negative and positive correlations with HAMD-17 items. At T1 and within the controls, no such relationships were observed. At T0 and T1, levels of both pro- and anti-inflammatory cytokines were significantly higher in treatment responders (ΔHAMD-17T0-T1≥50%,n=15) compared to non-responders. When controlled for baseline BDI, differences between groups were only found significant for IL-2 at T0. The results suggest cytokines are not generally pro-depressive but rather relate to more specific regulation of symptoms and severities in MD. Together with the association between cytokines and treatment responder status, these data support cytokines as a promising but still controversial biomarker of depression.

Depression, immune function, and early adrenarche in children

Despite consistent findings of an association between depression and immunity in adult and adolescent populations, little is known about the nature of this relationship at earlier ages. Studies of children have yielded mixed results, suggesting methodological confounds and/or the presence of significant moderating factors. Timing of adrenarche, the first phase of puberty that occurs during late childhood, is a plausible moderator of the depression-immunity relationship in late childhood due to its associations with both the immune system and psychological wellbeing. We hypothesized that: (1) a depression-immunity association exists in children, (2) this association is moderated by adrenarcheal timing, and, (3) this association is also moderated by gender. Data were drawn from a nested study of 103 participants (62 females, Mage=9.5, age range: 8.67-10.21 years) participating in a population based cohort study of the transition from childhood to adolescence (across puberty). Participants in this nested study completed the Children's Depression Inventory 2 (CDI-2) and provided morning saliva samples to measure immune markers (i.e., C-reactive protein, CRP; and secretory immunoglobulin A, SIgA). Using hierarchical regression, inflammation measured by CRP was positively associated with the negative mood/physical symptoms (NM/PS) subscale (β=0.23, t=2.33, p=0.022) of the CDI-2. A significant interaction effect of SIgA x adrenarcheal timing was found for NM/PS (β=-0.39, t=-2.19, p=0.031) and Interpersonal Problems (β=-0.47, t=-2.71, p=0.008). SIgA and NM/PS were positively associated for relatively late developers. SIgA and Interpersonal Problems were positively associated for late developers, and negatively associated for early developers. We suggest that both sets of findings might be partially explained by the immunosuppressive effect of the hormonal changes associated with earlier adrenarche, namely testosterone. These results also suggest that adrenarcheal timing has an effect on the association between depression and immunity, and is therefore an important measure in research with younger populations. Future research should utilize longitudinal designs to demonstrate direction of influence of variables, and use a broader range of pro- and anti-inflammatory markers.

Adolescent-Onset Depression: Are Obesity and Inflammation Developmental Mechanisms or Outcomes?

Depression often has its first onset during adolescence and is associated with obesity. Furthermore, inflammatory processes have been implicated in both depression and obesity, although research amongst adolescents is limited. This review explores associations between depression and obesity, depression and inflammation, and obesity and inflammation from a developmental perspective. The temporal relations between these factors are examined to explore whether obesity and elevated inflammation act as either risk factors for, or outcomes of, adolescent-onset depression. Sex differences in these processes are also summarized. We propose a model whereby increases in sex hormones during puberty increase risk for depression for females, which can lead to obesity, which in turn increases levels of inflammation. Importantly, this model suggests that inflammation and obesity are outcomes of adolescent depression, rather than initial contributing causes. Further research on biological and psychosocial effects of sex hormones is needed, as is longitudinal research with children and adolescents.

Serum cytokines and anxiety in adolescent depression patients: Gender effect

The present study compares the serum cytokine levels between adolescent depression patients and healthy controls and assesses correlation between depression, anxiety scores and serum levels of eight cytokines. Study also checked the variation in serum levels with medication status (medication free/naïve vs. patients on medication). Following clinical and psychometric assessment of 77 adolescent (aged 13-18 years) depression patients (49 males and 28 females; 56 medication free/naïve) and 54 healthy controls (25 males, 29 females), eight cytokines (IL-1β, IL-2, IL-6, IL-10, TNF-α, IFN-γ, TGF-β1 and IL-17A {denoted IL-17 throughout}) were measured in serum using ELISA. Depressed adolescents had significantly high levels of IL-2 (p<0.001) and IL-6 (p=0.03) as compared to controls. The female population skewed the result of one cytokine (IL-6) in patients. Anxiety scores showed positive correlation (only in female patients) with IL-1β, IL-10 and negative correlation with TGF-β1 and IL-17. The gender effect in relationship between anxiety and cytokines was not straightforward. On comparing study groups on the medication/naïve status, IL-2 and TGF-β1 showed significant difference between the groups (p<0.001, p=0.007 higher in medicated). Depression in adolescents was associated with elevation of proinflammatory serum cytokines with a gender bias for females. Anxiety scores correlated negatively with TGF-β1 and IL-17.

Comorbidity between depression and asthma via immune-inflammatory pathways: a meta-analysis

BACKGROUND

Depression is often present in patients with asthma and vice versa. In this review, we aimed to summarize reports on the comorbidity of depression and asthma, and to seek evidence that the biological mechanisms of allergy may have an important role linking asthma and depression.

METHOD

To explore the relationship and pathway underpinning this comorbidity, we reviewed medical articles and undertook a meta-analysis of epidemiological studies on (i) incidence of asthma in patients with depression; (ii) morbidity of depression in patients with asthma; (iii) concentration of cytokines in depressed subjects.

RESULTS

High level of comorbidity of asthma and depression was consistently demonstrated in 10 studies of patients with asthma and four studies of patients with depression. In search of biological connection of the two illnesses, thirty-eight studies were included for Meta-analyses examining differences in allergy related cytokines between patients with depression and non-depressive subjects. In people with depression, concentration of monocytes related cytokines such as IL-1 (1.56ng/mL, 95% CI: 0.00-3.12, p=0.05) was significantly higher than that in non-depressive control subjects. At the same time, some other inflammatory factors including IL-4 (5.77pg/mL, 95% CI: 2.34-9.21, p=0.00010), IL-6 (1.44ng/mL, 95% CI: 1.05-1.82, p<0.00001) and TNF-α(3.01ng/mL, 95% CI: 1.76-4.26, p<0.00001) were extremely significantly higher in depressed people compared with the controls. There was no significant differences of the T cell related cytokine levels, IFN-γ (-0.16ng/mL, 95% CI: -0.85-7.73, p=0.97), accompanied with IL-10 (0.67ng/mL, 95% CI: -0.84-2.18, p=0.38) between depressive and non-depressive groups.

CONCLUSIONS

The varying levels of certain cytokines play an important role in arousing and remitting asthma and depression. That suggests inflammatory response could be a common pathway adjusting both depression and asthma.

Serum inflammatory cytokines and depression in coronary artery disease

Background:

Severe depression may be accompanied by immune dysregulation and is also associated with increased risk of coronary artery disease (CAD).

Objectives:

We investigated serum levels of 10 cytokines and their relationship with depression in patients with cardiovascular diseases as well as healthy subjects in northeast of Iran.

Patients and Methods:

The study was carried out on 462 subjects (120 healthy subjects and 342 candidates undergoing angiography). The healthy subjects were referred for routine annual checkups or pre-employment examinations; they did not have clinically evident CAD. A questionnaire was used to obtain demographic data and the Beck depression inventory (BDI) was applied to assess depression. The Evidence Investigator^® platform was used for cytokines assays for IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, MCP-1 and IFN-γ, using sandwich chemiluminescent method. The statistical analysis was performed using SPSS version 11.5.

Results:

The mean age was 53.3 ± 11.5, 54.8 ± 11.3, and 59.5 ± 11.3 in healthy, angiography (-), and angiography (+) subjects, respectively (P < 0.05). There were significant differences in serum levels of IL-4, IL-6, IL-10, and MCP-1 cytokines, comparing subjects with CAD and healthy persons (P < 0.05). When all subjects were divided to with and without depression regardless of their cardiovascular status, there was a significant difference in serum levels of IL-8 and IL-6 between the groups (P < 0.05). When the subgroup with features of CAD was selected and divided to those with and without depression, there was also a significant difference in serum levels of IL-8 and TNF-α (P < 0.05).

Conclusions:

The positive interaction between depression and CAD was probably mediated by inflammatory mechanisms.

Inflammatory cytokine-associated depression

Inflammatory cytokines can sometimes trigger depression in humans, are often associated with depression, and can elicit some behaviors in animals that are homologous to major depression. Moreover, these cytokines can affect monoaminergic and glutamatergic systems, supporting an overlapping pathoetiology with major depression. This suggests that there could be a specific major depression subtype, inflammatory cytokine-associated depression (ICAD), which may require different therapeutic approaches. However, most people do not develop depression, even when exposed to sustained elevations in inflammatory cytokines. Thus several vulnerabilities and sources of resilience to inflammation-associated depression have been identified. These range from genetic differences in neurotrophic and serotonergic systems to sleep quality and omega-3 fatty acid levels. Replicating these sources of resilience as treatments could be one approach for preventing "ICAD". This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Inflammation in children and adolescents with neuropsychiatric disorders: a systematic review

OBJECTIVE

There has been rapid growth in research regarding inflammation in neuropsychiatric disorders as it relates to youth. We therefore set out to systematically review the literature on inflammation and neuropsychiatric disorders in children and adolescents.

METHOD

A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies were included if proinflammatory markers (PIMs) in children and/or adolescents with neuropsychiatric disorders were measured.

RESULTS

Sixty-seven studies were included, involving 3,952 youth. Evidence for a proinflammatory state is strongest for autism spectrum disorders (ASD). PIMs are elevated in children and adolescents with major depressive disorder (MDD), bipolar disorder (BD), post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), Tourette's disorder (TD), attention-deficit/hyperactivity disorder (ADHD), and schizophrenia (SZ). However, the data are inconsistent. Evidence for specific PIMs is equivocal at this stage, although the findings in youth with MDD, BD, and PTSD converge with the extant adult literature in these areas. Definitive conclusions are limited by methodologic factors including cross-sectional and retrospective study design, between-study differences in specific markers and methods of analysis, small sample size, and other sources of heterogeneity.

CONCLUSION

The literature regarding inflammation among children and adolescents with neuropsychiatric disorders represents nearly 4,000 youth. There is preliminary evidence for elevated markers of inflammation in this population. Larger, prospective studies are needed to realize the goal of inflammatory markers informing clinical practice. In the interim, present findings suggest that further examination of this topic is warranted.

Internalizing and externalizing behaviors predict elevated inflammatory markers in childhood

BACKGROUND

Children with behavior problems, such as internalizing or externalizing disorders, are at increased risk for poorer physical health in adulthood. Inflammation has been posited as a potential biological mediator underlying this association. However, it is unclear how early in development associations between behavior problems and inflammation may be detected, and whether associations are present for both internalizing and externalizing behaviors in pre-pubertal children.

METHODS

Using data from children in the Avon Longitudinal Study of Parents and Children, we examined associations between behavior problems at age 8 (assessed via the parent-report Strengths and Difficulties Questionnaire) and inflammatory markers assessed at age 10. Inflammatory markers included C-reactive protein (CRP; n=4069) and interleukin-6 (IL-6; n=4061). We further evaluated whether body mass index (BMI) mediated associations, and tested for potential reverse causality by considering whether age 10 inflammation was associated with changes from initial levels to age 12 behavior problems.

RESULTS

After adjusting for relevant covariates, age 8 externalizing behaviors were associated with elevated CRP at age 10, and age 8 internalizing and externalizing behaviors were associated with elevated IL-6 at age 10 (p's<0.05). We found no evidence that observed associations were mediated by BMI or that inflammatory markers at age 10 were associated with increased internalizing or externalizing behavior problems at age 12.

CONCLUSIONS

These findings document an association between behavior problems and elevated concentrations of CRP and IL-6 at 10 years. Heightened inflammation in childhood may be a pathway through which early behavior problems increase risk for adult chronic diseases.

Interleukin-1β is associated with depressive episode in major depression but not in bipolar disorder

Our work was sought to investigate possible changes in peripheral levels of interleukin-1β (IL-1β) according to the diagnosis of major depression (MD) and bipolar disorder (BD) and in different mood episodes. This is a cross-sectional nested in a population-based study comparing 240 young adults (80 controls, 80 MD and 80 BD), balanced for age and gender. Serum levels of IL-1β were significantly higher in MD when compared to control or BD subjects. In addition, when divided by current mood episode, MD subjects in current depression presented higher IL-1β levels than controls. No differences in IL-1β levels were found between different episodes of BD (euthymic, depressed, mania or mixed). Moreover, the use of psychiatric medication was very low in our sample and not associated with changes in IL-1β levels. In conclusion, increased peripheral IL-1β might be a useful marker associated with a depressive episode in the context of MD.

Acute phase protein and cytokine levels in serum and saliva: a comparison of detectable levels and correlations in a depressed and healthy adolescent sample

Recent research has examined associations between inflammation and mental health, and has increasingly focused on utilising younger samples to characterise the temporal relationship between inflammatory responses and the emergence of other symptoms. These studies have typically used blood to measure inflammation, although rates of detection for many inflammatory markers appear to be low. Saliva is a safe and low-cost alternative, and adult research has shown that levels of some salivary markers correlate well with those in serum. However, no research has examined this association in young people. This study examined 16 inflammatory markers in serum and saliva in 17 depressed adolescents and 18 healthy controls, aged 13-18 years. In general, detection rates were higher in saliva compared to in serum. When non-detectable levels were excluded, serum levels of C-reactive protein (CRP) correlated with salivary CRP (r=0.424, p=0.015), and this correlation appeared to only exist for those individuals with high levels of serum CRP (r=0.599, p=0.014). However, when non-detectable levels were included as zero, salivary levels of CRP, interleukin (IL)-2, IL-12p70, and interferon (IFN)-γ correlated with their serum counterparts. No significant clinical group differences in any acute phase proteins or cytokines were present. This study suggests that saliva can be used to measure inflammation in studies with adolescent participants, especially CRP, as it appears to correlate with systemic inflammation for those individuals who are expected to have high levels of inflammation. Implications for future directions in research on salivary inflammatory markers are discussed.

The association between immune activation and manic symptoms in patients with a depressive disorder

Although recent studies have shown that immunological processes play an important role in the pathophysiology of mood disorders, immune activation may only be present in specific subgroups of patients. Our study aimed to examine whether immune activation was associated with (a) the presence of manic symptoms and (b) the onset of manic symptoms during 2 years of follow-up in depressed patients. Patients with a depressive disorder at baseline (N=957) and healthy controls (N=430) were selected from the Netherlands Study of Depression and Anxiety. Assessments included lifetime manic symptoms at baseline and two-year follow up, as well as C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) at baseline. Within depressed patients, immune activation was not related to the presence or absence of lifetime manic symptoms at baseline. However, CRP levels were strongly elevated in depressed men who developed manic symptoms compared with those who did not develop manic symptoms over 2 years (P<0.001, Cohen's d=0.89). IL-6 and TNF-α were also higher in depressed men with an onset of manic symptoms, but this association was not significant. However, we found that the onset of manic symptoms was particularly high in men with multiple elevated levels of inflammatory markers. Depressed men who developed manic symptoms during follow-up had increased immunological activity (especially CRP) compared with depressed men who did not develop manic symptoms. Further research should explore whether a treatment approach focusing on inflammatory processes may be more effective in this specific subgroup of depressed patients.

Plasma Levels of IL-23 and IL-17 before and after Antidepressant Treatment in Patients with Major Depressive Disorder

OBJECTIVE

Cytokines are believed to have a role in the pathophysiology of major depression. The alteration in levels of pro-inflammatory cytokines [interleukin 1β (IL-1β), IL-2, IL-6, IL-12, interferon γ, and tumor necrosis factor α] in major depression supports the cytokine hypothesis of this illness. IL-23 and IL-17 are also pro-inflammatory cytokines, but few studies have focused on their role in major depression. This study investigated the potential role of the IL-23 and IL-17 axis in major depression.

METHODS

Plasma IL-23 and IL-17 levels were measured in 26 major depressive disorder (MDD) patients before and after 6-week treatment with antidepressants; these levels were measured in 28 age- and sex-matched normal controls. Depression severity was assessed using the Hamilton Depression Rating Scale (HDRS). IL-23 and IL-17 plasma levels were estimated using quantitative enzyme-linked immunosorbent assay.

RESULTS

Pre-treatment plasma levels of IL-23 and IL-17 in MDD patients were not significantly different from those of normal controls. In MDD patients, IL-23 and IL-17 levels after 6 weeks of antidepressant treatment were not different from the baseline levels. There was no significant correlation between changes in the cytokine levels and changes in the HDRS scores representing the severity of depression.

CONCLUSION

The present study does not support a potential involvement of IL-23 and IL-17 axis in major depression. Replication and extension using a larger sample are required.

Research review: the role of cytokines in depression in adolescents: a systematic review

BACKGROUND

While cytokines have been implicated in the pathophysiology of depression in adults, the potential role in younger age groups such as adolescents is less clear. This article therefore reviews the literature (a) to explore the relationship between cytokines and depression in adolescents, and (b) to examine how cytokines may be related to adolescent depression in the context of other neurobiological theories of depression.

METHOD

A systematic review of the scientific literature on the subject was conducted in February 2013, searching the Web of Knowledge, PubMed (Medline), PsycInfo and Cochrane electronic databases.

RESULTS

Eighteen studies were identified measuring both depression or depressive symptoms and cytokines or immune markers in adolescents. Adolescents with depression show age-specific characteristics of the immune and inflammatory system, specifically in NK cell activity and in pro-inflammatory cytokines (such as IL-1β and TNF-α). In addition, the role of cytokines in adolescent depression is influenced by neurodevelopment, hormonal changes, stress and trauma.

CONCLUSIONS

There may be differences in the neurobiology of adolescent major depressive disorder (MDD) compared with adult MDD. Increased understanding of the role of cytokines in adolescent MDD may lead to improved outcomes in the treatment of adolescent depression.

Ketamine exerts antidepressant effects and reduces IL-1β and IL-6 levels in rat prefrontal cortex and hippocampus

Ketamine has fast-acting and robust antidepressant effects in animal models and depressed patients. It has been hypothesized that its underlying mechanism of action is associated with the inflammatory response in the central nervous system. Therefore, the present study was designed to investigate the antidepressant effects of ketamine and the expression of interleukin (IL)-1β and IL-6 in the prefrontal cortex and hippocampus of a rat model. Twenty Wistar rats were randomly divided into 2 groups (each group, n=10); the saline group and the ketamine group. On the 1st day, rats undertook a forced swimming test (FST) for 15 min (pre-test session). On the 2nd day, saline or ketamine was administered intraperitoneally 30 min before the test session. Following this, rats performed another FST for 5 min (test session) and the immobility time was recorded. The rats were then sacrificed, and the prefrontal cortex and hippocampus were harvested for determination of IL-1β and IL-6 levels. Compared with the saline group, ketamine administration significantly decreased the immobility time of rats during the FST (P<0.05). In addition, the ketamine group demonstrated a statistically significant decrease in the expression of IL-1β and IL-6 in rat prefrontal cortex and hippocampus compared with the saline group (P<0.05). Ketamine-induced antidepressant effects are associated with decreased levels of IL-1β and IL-6 in rat prefrontal cortex and hippocampus.

IL-1β, IL-6, IL-8, IL-10, IFN-γ, TNF-α and its relationship with lipid parameters in patients with major depression

There is some evidence that an immune response with an increased production of proinflammatory cytokines frequently accompanies major depression. The aim of this study was to determine the serum levels of interleukines (IL-1β, IL-6, IL-8, IL-10), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and immonuglobulines (IgG, IgA and IgM) levels and to examine the relationships between all above parameters and lipid parameters. The study group included 30 patients and 30 healthy volunteers. Although total cholesterol, HDL-cholesterol, and IgM levels were increased significantly (p < 0.05) in patients and compared to those of the controls, no statistically significant differences (p > 0.05) were observed with other parameters. IFN-γ were positively correlated with total cholesterol (r = 0.425; P = 0.019) and LDL-cholesterol (r = 0.391; P = 0.032) levels in patients. Other cytokines and immunoglobulins did not show any correlation with lipid parameters. It was concluded that although no differences was observed in cytokines and immunoglobulin levels in the present study, the dysregulation of the lipids and immune system including the cytokine network is associated with the etiology and pathophysiology of major depressive disorders.