Brain derived neurotrophic factor (BDNF) polymorphism moderates the interactive effect of 5-HTTLPR polymorphism and childhood abuse on diagnoses of major depression in women

Adverse childhood experience and depression: the role of gut microbiota

Depression is the most common psychiatric disorder that burdens modern society heavily. Numerous studies have shown that adverse childhood experiences can increase susceptibility to depression, and depression with adverse childhood experiences has specific clinical-biological features. However, the specific neurobiological mechanisms are not yet precise. Recent studies suggest that the gut microbiota can influence brain function and behavior associated with depression through the "microbe-gut-brain axis" and that the composition and function of the gut microbiota are influenced by early stress. These studies offer a possibility that gut microbiota mediates the relationship between adverse childhood experiences and depression. However, few studies directly link adverse childhood experiences, gut microbiota, and depression. This article reviews recent studies on the relationship among adverse childhood experiences, gut microbiota, and depression, intending to provide insights for new research.

Exploration of the Moderating Effects of Physical Activity and Early Life Stress on the Relation between Brain-Derived Neurotrophic Factor (BDNF) rs6265 Variants and Depressive Symptoms among Adolescents

Depression affects one in five persons at 18 years of age. Allele A of the brain-derived neurotrophic factor (BDNF) rs6265 is considered to be a risk factor for depression. Previous studies of the interaction between BDNF rs6265, early adversity, and/or physical activity have shown mixed results. In this study, we explored the relation between BDNF rs6265 polymorphism and childhood stress, as well as the moderating effect of physical activity in relation to depressive symptoms using binary logistic regressions and process models 1, 2 and 3 applied to data obtained at three times (waves 1, 2 and 3) from the Survey of Adolescent Life in Västmanland cohort study (SALVe). Results revealed that both childhood stress and physical activity had a moderation effect; physical activity in wave 1 with an R2 change = 0.006, p = 0.013, and the Johnson−Neyman regions of significance (RoS) below 1.259, p = 0.05 for 11.97%; childhood stress in wave 2 with the R2 change = 0.008, p = 0 002, and RoS below 1.561 with 26.71% and >4.515 with 18.20%; and a three-way interaction in wave 1 in genotype AA carriers. These results suggest that allele A is susceptible to physical activity (positive environment) and childhood stress (negative environment).

Time moderates the interplay between 5-HTTLPR and stress on depression risk: gene x environment interaction as a dynamic process

The serotonin-transporter-linked promoter region (5-HTTLPR) has been widely investigated as contributing to depression vulnerability. Nevertheless, empirical research provides wide contrasting findings regarding its involvement in the etiopathogenesis of the disorder. Our hypothesis was that such discrepancy can be explained considering time as moderating factor. We explored this hypothesis, exploiting a meta analytic approach. We searched PubMed, PsychoINFO, Scopus and EMBASE databases and 1096 studies were identified and screened, resulting in 22 studies to be included in the meta-analyses. The effect of the 5-HTTLPR x stress interaction on depression risk was found to be moderated by the following temporal factors: the duration of stress (i.e. chronic vs. acute) and the time interval between end of stress and assessment of depression (i.e. within 1 year vs. more than 1 year). When stratifying for the duration of stress, the effect of the 5-HTTLPR x stress interaction emerged only in the case of chronic stress, with a significant subgroup difference (p = 0.004). The stratification according to time interval revealed a significant interaction only for intervals within 1 year, though no difference between subgroups was found. The critical role of time interval clearly emerged when considering only chronic stress: a significant effect of the 5-HTTLPR and stress interaction was confirmed exclusively within 1 year and a significant subgroup difference was found (p = 0.01). These results show that the 5-HTTLPR x stress interaction is a dynamic process, producing different effects at different time points, and indirectly confirm that s-allele carriers are both at higher risk and more capable to recover from depression. Overall, these findings expand the current view of the interplay between 5-HTTLPR and stress adding the temporal dimension, that results in a three-way interaction: gene x environment x time.

Childhood Adversity and the Association Between Stress Sensitivity and Problematic Alcohol Use in Adults

Early life adversity (ELA) increases the risk of problematic alcohol use and alcohol use disorder (AUD). However, it is unclear why some but not all ELA-exposed individuals develop problematic alcohol use. Research is needed to determine how this environmental risk factor interacts with underlying neurobehavioral vulnerabilities to problem alcohol use. Hypersensitivity to uncertain threats (U-threat) has been posited as an endophenotype for AUD that might aid in the refinement of mechanistic models of problematic alcohol use. Therefore, U-threat hypersensitivity requires examination as a possible individual difference factor that facilitates problematic alcohol use among ELA-exposed individuals. We examined the unique and interactive effects of ELA and U-threat reactivity on problem drinking and depressive and anxiety symptom severity. Participants (N = 131) completed a well-validated threat-of-shock task, and startle eyeblink potentiation was recorded to index aversive responding. Individuals also completed self-report measures of alcohol use, anxiety, and depressive symptoms. Results demonstrated a positive association between ELA and higher levels of problematic alcohol use at high levels of U-threat reactivity, β = .75, t = 3.93, p < .001. Conversely, at low levels of U-threat reactivity, ELA exposure was negatively associated with problematic alcohol use, β = -.49, t = -2.30, p = .023. There was no significant ELA x U-Threat reactivity interaction on anxiety or depression. U-threat response strongly interacts with ELA exposure, affecting the direction of the association between ELA and problem drinking. U-threat reactivity may be a promising target for the prevention and treatment of problematic drinking among ELA-exposed individuals.

Adverse childhood experiences, the serotonergic system, and depressive and anxiety disorders in adulthood: A systematic literature review

BACKGROUND

Recent studies have examined the role that the serotonergic system plays in moderating the association between adverse childhood experiences (ACEs) and depressive and anxiety disorders in adulthood. The aim of this literature review is to synthesize studies that examined serotonin's impact in relation to ACEs, and depressive and anxiety disorders in this population.

METHODS

Published studies from 2008 to 2018 were retrieved from PubMed, CINAHL, and PsychINFO databases, and were included if ACEs, the serotonergic system, and depressive and or anxiety disorders were assessed in those with a mean age between nineteen and forty.

RESULTS

Twenty-eight studies were included. Various genetic polymorphisms in the serotonergic signaling system moderated the association between ACEs and depression. Additionally, selective serotonin reuptake inhibitors with a high affinity for the serotonin transporter, resulted in poor treatment outcomes for those with history of ACEs.

CONCLUSION

Additional research is needed in order to further define the role that the serotonergic genes play in the association between ACEs and depressive and anxiety disorders in adulthood.

Potential biomarkers: differentially expressed proteins of the extrinsic coagulation pathway in plasma samples from patients with depression

Depression is a severe disabling psychiatric illness and the pathophysiological mechanisms remain unknown. In previous work, we found the changes in extrinsic coagulation (EC) pathway proteins in depressed patients compared with healthy subjects were significant. In this study, we screened differentially expressed proteins (DEPs) in the EC pathway, and explored the molecular mechanism by constructing a protein-protein interaction (PPI) network. The DEPs of the EC pathwaywere initially screened by isobaric tags for relative and absolute quantification (iTRAQ) in plasma samples obtained from 20 depression patients and 20 healthy controls, and were then identified by Enzyme-linked immunosorbent assays (ELISAs). Ingenuity Pathway Analysis (IPA) software was used to analyse pathway. The differentially expressed genes (DEGs) were identified by analyzing the GSE98793 microarray data from the Gene Expression Omnibus database using the Significance Analysis for Microarrays (SAM, version 4.1) statistical method. Cytoscape version 3.4.0 software was used to construct and visualize PPI networks. The results show that Fibrinogen alpha chain (FGA), Fibrinogen beta chain (FGB), Fibrinogen gamma chain (FGG) and Coagulation factor VII (FVII) were screened in the EC pathway from depression patient samples. FGA, FGB, and FGG were significantly up-regulated, and FVII was down-regulated. Thirteen DEGs related to depression and EC pathways were identified from the microarray database. Among them NF-κB Inhibitor Beta (NFKBIB) and Heat shock protein family B (small) member 1 (HSPB1) were highly correlated with EC pathway. We conclude that EC pathway is associated with depression, which provided clues for the biomarker development and the pathogenesis of depression.

Early Life Adversity as a Moderator of Symptom Change following Selective Serotonin Reuptake Inhibitors and Cognitive Behavioral Therapy

Background

Early Life Adversity (ELA) is consistently linked to chronic, treatment-resistant depression and anxiety. Selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy (CBT) represent the two first-line treatments for internalizing disorders. However, little is known about the efficacy of these therapies for individuals with ELA, particularly within heterogeneous cohorts of patients with high levels of comorbidity.

Methods

Treatment seeking adults with depression and/or anxiety were randomized to twelve weeks of SSRI (n = 46) or CBT (n = 50), and internalizing disorder symptoms were assessed pre- and post-treatment. Individuals with and without ELA were included.

Results

Both SSRI and CBT resulted in reductions in internalizing symptoms, as expected. A significant ELA by treatment type interaction for depression, but not anxiety, also emerged. Individuals with a positive history of ELA had a greater reduction in depression symptoms following SSRIs compared with CBT. In contrast, individuals with a negative history of ELA had a greater reduction in depression symptoms following CBT compared with SSRIs.

Conclusions

Findings suggest that SSRIs may be particularly effective for individuals with ELA and CBT may be particularly effective for individuals without ELA in reducing depression, but not anxiety, symptoms. Clinical implications and future directions are discussed.

The relationship between occupational stress, musculoskeletal disorders and the mental health of coal miners: The interaction between BDNF gene, TPH2 gene polymorphism and the environment

OBJECTIVE

Mental disorders are prevalent among the population and seriously endanger people's working ability as well as their physical and mental health. This study employed stratified cluster random sampling to examine occupational stress, musculoskeletal disorders (MSDs) and the mental health status of 1675 coal miners in Xinjiang.

METHODS

A cross-sectional investigation was carried out, and BDNF (rs6265, rs10835210) gene polymorphism and TPH2(rs4570625, rs4131347) gene polymorphism were identified in 30% of the study's participants. This study aimed to analyze the relationship between mental disorders, occupational stress and MSDs, and to explore the role of gene-gene and gene-environment interactions in respect to the incidence of psychological disorders. On this basis, the risk prediction model of mental disorders was constructed.

RESULTS

The study identified the following risk factors for mental disorders among coal miners: Female, age, four shifts, coal miners, college education or above, single, occupational stress, and MSDs. MSDs, BDNF gene (rs6265) and TPH2 gene (rs4570625) are directly related to mental disorders, and interactions were found between MSDs and BDNF gene (rs6265),TPH2 gene (rs4570625), affecting the incidence of mental disorders. The Bayesian network model of mental disorders showed that MSDs, educational level, TPH2 gene (rs4570625) and marital status had a higher influence on mental disorders. Monthly income and educational level can indirectly affect mental disorders through occupational stress. BDNF gene (rs6265) and TPH2 gene (rs4570625) can indirectly affect mental disorders through MSDs. There may be an interaction between MSDs and educational level.

CONCLUSIONS

Besides demographic characteristics, occupational stress and musculoskeletal disorders are also factors affecting the mental health of coal miners. It was found that BDNF rs10835210, TPH2 rs4570625 and TPH2 rs4131347 interact with each other, increasing the risk of mental disorders among coal miners.

The roles of early-life adversity and rumination in neural response to emotional faces amongst anxious and depressed adults

BACKGROUND

Early-life adversity (ELA) is a risk factor for internalizing psychopathology (IP). ELA is also linked to alterations in neural phenotypes of emotion processing and maladaptive emotion regulatory strategies, such as ruminative brooding, in adulthood. We therefore expected that ELA would predict cortical brain activation to emotional faces in transdiagnostic IP and in turn, mediate the extent of rumination amongst patients with IPs and ELA (IP + ELA).

METHOD

One hundred and thirty-two individuals, including 102 treatment-seeking adults with heterogeneous IPs and 30 healthy controls (HCs) performed an Emotional Face-Matching Task during functional magnetic resonance imaging. Whole-brain analyses compared HC (n = 30), IP (n = 52), and IP + ELA (n = 50) neural responses to emotional (angry, fearful, happy, and sad) faces v. shapes, controlling for depression and anxiety symptoms. Parameter estimates of activation were extracted for significant between-group differences and tested as a mediator of ruminative brooding in IP + ELA.

RESULTS

IP + ELA demonstrated increased activation in the superior frontal gyrus and anterior cingulate cortex (fear), superior parietal lobule, precuneus, posterior cingulate, and inferior temporal gyrus (fear only), and cuneus (fear and angry). These regions were preferentially correlated with ruminative brooding in IP + ELA, many of which mediated the link between IP + ELA and ruminative brooding.

CONCLUSIONS

Results provide evidence that ELA history amongst IP patients augments engagement of brain regions involved in emotion processing, above and beyond what is accounted for by current symptoms. Though longitudinal designs are needed, alterations in the neural correlates of maladaptive processing of socio-emotional information may be a common pathway by which ELA poses risk for psychopathology.

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.

BDNF Val66Met polymorphism, life stress and depression: A meta-analysis of gene-environment interaction

BACKGROUND

Depression is thought to be multifactorial in etiology, including genetic and environmental components. While a number of gene-environment interaction studies have been carried out, meta-analyses are scarce. The present meta-analysis aimed to quantify evidence on the interaction between brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and stress in depression.

METHODS

Included were 31 peer-reviewed with a pooled total of 21060 participants published before October 2016 and literature searches were conducted using PubMed, Wolters Kluwer, Web of Science, EBSCO, Elsevier Science Direct and Baidu Scholar databases.

RESULTS

The results indicated that the Met allele of BDNF Val66Met polymorphism significantly moderated the relationship between stress and depression (Z=2.666, p = 0.003). The results of subgroup analysis concluded that stressful life events and childhood adversity separately interacted with the Met allele of BDNF Val66Met polymorphism in depression (Z = 2.552, p = 0.005; Z = 1.775, p = 0.03).

LIMITATIONS

The results could be affected by errors or bias in primary studies which had small sample sizes with relatively lower statistic power. We could not estimate how strong the interaction effect between gene and environment was.

CONCLUSIONS

We found evidence that supported the hypothesis that BDNF Val66Met polymorphism moderated the relationship between stress and depression, despite the fact that many included individual studies did not show this effect.

Gene-environment interactions between stress and 5-HTTLPR in depression: A meta-analytic update

BACKGROUND

Meta-analyses have yielded contradictory findings concerning the role of 5-HTTLPR in interaction with stress (GxE) in depression. The current meta-analysis investigates if these contradictory findings are a result of differences between studies in methodological approaches towards the assessment of stress and depression.

METHODS

After performing a systematic database search (February to December 2016), first, a meta-analysis was used to investigate the total effect size and publication bias. Second, stratified meta-analyses were used to investigate the potential moderating influence of different methodological approaches on heterogeneity of study findings. Third, a meta-regression was used to investigate the combined influence of the methodological approaches on the overall effect size.

RESULTS

Results showed a small but significant effect of 5-HTTLPR in interaction with stress in the prediction of depression (OR[95%CI] = 1.18[1.09; 1.28], n = 48 effect sizes from 51 studies, totaling 51,449 participants). There was no evidence of publication bias. Heterogeneity of effect sizes was a result of outliers and not due to different methodological approaches towards the assessment of stress and depression. Yet, there was some evidence that studies adopting a categorical and interview approach to the assessment of stress report higher GxE effects, but further replication of this finding is needed.

LIMITATIONS

A large amount of heterogeneity (i.e., 46%) was not explained by the methodological factors included in the study and there was a low response rate of invited studies.

CONCLUSIONS

The current meta-analysis provides new evidence for the robustness of the interaction between stress and 5-HTTLPR in depression.

Childhood Adversities and Depression in Adulthood: Current Findings and Future Directions

Considerable support exists supporting a relationship between childhood adversities and adult depression. Consistent evidence has emerged linking early life adversities with a more chronic course for depression, as well as to poorer treatment outcomes. What remain decidedly less clear, however, are the moderators and mediating mechanisms underlying this association. This article provides a review of the existing research relating early adversities to adult depression, as well as recent studies suggestive of potential mediators and moderators of this relation. Advances in these areas are important for their potential to lead to the identification of new targets for clinical intervention for adults with a history of childhood adversities, as well as to the development of individually tailored prevention and treatment strategies.