Glucocorticoid sensitivity in mood disorders

The mediation effect of glucocorticoid receptor gene (NR3C1) methylation between childhood maltreatment and depressive symptoms in Chinese adolescents: A 2-year longitudinal study

This three-wave longitudinal study examined whether methylation alterations in promoter exon 1F of a stress-related gene-NR3C1 (NR3C1-1F)-explained the longitudinal associations between childhood maltreatment and adolescent depressive symptoms. A total of 370 Han Chinese adolescents (Mage  = 16.31 ± 1.28 years; 51.4% girls) recruited from Shandong, China were tracked from 2018 to 2020. The results showed that the severity of childhood maltreatment, especially that of emotional abuse and physical neglect, conferred risk for adolescent depressive symptoms via reducing NR3C1-1F methylation levels. These mediation effects of NR3C1-1F methylation did not vary between adolescent sex or NR3C1 BclI and Tth111I polymorphisms. The findings highlight how childhood maltreatment contributes to psychopathology development at a biological level.

The interplay of hypoxic and mental stress: Implications for anxiety and depressive disorders

Adequate oxygen supply is essential for the human brain to meet its high energy demands. Therefore, elaborate molecular and systemic mechanism are in place to enable adaptation to low oxygen availability. Anxiety and depressive disorders are characterized by alterations in brain oxygen metabolism and of its components, such as mitochondria or hypoxia inducible factor (HIF)-pathways. Conversely, sensitivity and tolerance to hypoxia may depend on parameters of mental stress and the severity of anxiety and depressive disorders. Here we discuss relevant mechanisms of adaptations to hypoxia, as well as their involvement in mental stress and the etiopathogenesis of anxiety and depressive disorders. We suggest that mechanisms of adaptations to hypoxia (including metabolic responses, inflammation, and the activation of chemosensitive brain regions) modulate and are modulated by stress-related pathways and associated psychiatric diseases. While severe chronic hypoxia or dysfunctional hypoxia adaptations can contribute to the pathogenesis of anxiety and depressive disorders, harnessing controlled responses to hypoxia to increase cellular and psychological resilience emerges as a novel treatment strategy for these diseases.

Variation in glucocorticoid sensitivity and the relation with obesity

Increasing evidence points to a relation between increased glucocorticoid (GC) exposure and weight gain. In support, long-term cortisol measurements using hair analysis revealed that many individuals with obesity appear to have cortisol values in the high physiological range. The mechanisms behind this relationship need to be determined in order to develop targeted therapy to reach sustainable weight loss in these subgroups. The effect of GCs is not only determined by the plasma concentration of GCs but also by individual differences in GC sensitivity and the target tissue, which can be analyzed by functional GC assays. GC sensitivity is influenced by multiple genetic and acquired (e.g., disease-related) factors, including intracellular GC availability, hormone binding affinity, and expression levels of the GC receptors and their isoforms, as well as factors involved in the modulation of gene transcription. Interindividual differences in GC sensitivity also play a role in the response to exogenous GCs, with respect to both therapeutic and adverse effects. Accordingly, in this review, we summarize current knowledge on mechanisms that influence GC sensitivity and their relationships with obesity and discuss personalized treatment options targeting the GC receptor.

Pediatric Cancer Survivorship: Impact Upon Hair Cortisol Concentration and Family Functioning

A clearer understanding of the association between a biomarker of long-term stress reactivity and family functioning among pediatric cancer survivors may guide both survivorship research and clinical practice. The current study examined the relationship between a long-term measure of hypothalamic-pituitary-adrenal (HPA) activity (cortisol concentration; CORT_HAIR) and parent-reported family functioning (Family Environment Scale; FES) in a cross-sectional sample of survivors (n = 26) and controls (n = 53). Child CORT_HAIR was not different in survivors and controls, though treatment severity was significantly related to child survivor CORT_HAIR. Child CORT_HAIR and parent CORT_HAIR were positively correlated. Cancer survivor parents reported greater FES Organization. Child CORT_HAIR was inversely associated with FES Independence, while parent CORT_HAIR was inversely correlated with FES Organization. Parent CORT_HAIR and FES Independence were significant and unique predictors of child CORT_HAIR. Our results provide preliminary evidence for a relationship between a stress biomarker, child CORT_HAIR, and family functioning among pediatric cancer survivors and controls.

FKBP5 and early life stress affect the hippocampus by an age-dependent mechanism

Early life stress (ELS) adversely affects the brain and is commonly associated with the etiology of mental health disorders, like depression. In addition to the mood-related symptoms, patients with depression show dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, increased peripheral inflammation, and structural brain alterations. Although the underlying causes are unknown, polymorphisms in the FK506-binding protein 5 (FKBP5) gene, a regulator of glucocorticoid receptor (GR) activity, interact with childhood adversities to increase vulnerability to depressive disorders. We hypothesized that high FKBP5 protein levels combined with early life stress (ELS) would alter the HPA axis and brain, promoting depressive-like behaviors. To test this, we exposed males and females of a mouse model overexpressing FKBP5 in the brain (rTgFKBP5 mice), or littermate controls, to maternal separation for 14 days after birth. Then, we evaluated neuroendocrine, behavioral, and brain changes in young adult and aged mice. We observed lower basal corticosterone (CORT) levels in rTgFKBP5 mice, which was exacerbated in females. Aged, but not young, rTgFKBP5 mice showed increased depressive-like behaviors. Moreover, FKBP5 overexpression reduced hippocampal neuron density in aged mice, while promoting markers of microglia expression, but these effects were reversed by ELS. Together, these results demonstrate that high FKBP5 affects basal CORT levels, depressive-like symptoms, and numbers of neurons and microglia in the hippocampus in an age-dependent manner.

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High FKBP5 reduces basal corticosterone levels in mice, especially in females.

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ELS prevents FKBP5-induced susceptibility to depressive-like behavior in aged mice.

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FKBP5 overexpression reduces hippocampal neuron density in aged mice, while increasing microglial markers.

Occurrence of mental disorders in nonspecific inflammatory bowel diseases: a primary or secondary problem in relation to the biological therapy used?

Introduction: Nonspecific inflammatory bowel diseases include Crohn’s disease (CD) and ulcerative colitis (CU – colitis ulcerosa), which are chronic diseases characterized by periods of exacerbation and remission. Extraintestinal complications caused by the disease and the applied treatment, mainly steroid therapy, constitute a predisposition to infections and mental disorders such as depressive disorders with apathy, slowness of movement or agitation, and even manic syndromes.

Aim and method: The aim of this study was to review the literature on the occurrence of primary and secondary mental disorders in the course of inflammatory bowel diseases. The literature in the Google Scholar database was reviewed using the following keywords: colitis ulcerosa, Crohn disease, depression, mental disorders, inflammatory bowel disease. The time descriptors 2011-2021 were also used.

Conclusions: The review of epidemiological studies shows that the most common mental disorders in nonspecific inflammatory bowel diseases are anxiety and depression disorders. The effect of steroid therapy on the development of mental disorders is equally significant. Most of the available empirical data relating to corticosteroids confirm the correlation between the drugs and depressive symptoms, and other psychiatric effects, including mania and psychosis.

Summary: As with most chronic diseases, the prevalence of anxiety and depression disorders is higher in nonspecific inflammatory bowel diseases than in the general population.

The Glucocorticoid Receptor Gene (NR3C1) 9β SNP Is Associated with Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) has been associated with glucocorticoid (GC) hypersensitivity. Although genetic factors account for 30–46% of the variance in PTSD, no associations have been found between single nucleotide polymorphisms (SNPs) of the GC receptor (GR) gene (NR3C1) and risk for this disorder. We studied the association of five SNPs in the GR gene (rs10052957, rs6189/rs6190, rs6195, rs41423247, and rs6198) and haplotypes with PTSD, in a group of Portuguese male war veterans (33 with lifetime PTSD, 28 without). To determine whether the 9β SNP (rs6198) was associated with chronically altered cortisol levels, we evaluated hair cortisol concentrations (HCC) in a sample of 69 veterans’ offspring. The 9β variant (G allele) was significantly associated with lifetime PTSD under a dominant model of inheritance. The 9β variant was also significantly associated with severity of current PTSD symptoms. The haplotype analysis revealed an association between a common haplotype comprising the 9β risk allele and lifetime PTSD. Carriers of the 9β risk allele had significantly lower HCC than non-carriers. We found the 9β risk allele and a haplotype comprising the 9β risk allele of the GR gene to be associated with PTSD in veterans. This 9β risk allele was also associated with lower HCC in their offspring.

Hypothalamic-pituitary-adrenal axis-related genes and cognition in major mood disorders and schizophrenia: a systematic review

Hypothalamic-pituitary-adrenal (HPA) axis dysregulation and cognitive deficits are two well-characterized endophenotypes present in different serious mental illnesses (SMIs), including major depressive disorder, bipolar disorder and schizophrenia. Our aim was to study the influence of genetic and epigenetic variations in HPA axis-related genes on cognitive performance in clinical samples, including patients with major mood disorders and schizophrenia. A systematic search was performed using PubMed (Medline), PsycINFO and Scopus databases. The systematic review identified 12 studies dealing with HPA-related genes and cognition in samples including patients with SMIs, focusing on single nucleotide polymorphism (SNP) variants, while no studies analysing epigenetic variations were found. The results suggest different and specific effects on the cognitive performance of SNP variants in the HPA axis-related genes studied, as well as interactions with traumatic experiences. There was high heterogeneity in the studied samples, genes analysed, and cognitive tasks evaluated. The relationship between HPA-related genes and cognition in SMIs is still largely unknown, and further studies including larger samples and epigenetic variations are needed.

Hair cortisol concentrations in chronic central serous chorioretinopathy

PURPOSE

Central serous chorioretinopathy (CSC), a distinct form of macular degeneration, has been associated with glucocorticoid use and possibly also with an increased endogenous activity of the hypothalamic-pituitary-adrenal (HPA) axis. To estimate long-term glucocorticoid exposure, measurement of hair cortisol concentrations (HCC) has emerged. This cross-sectional study aimed to investigate HCC, as a reflection of chronic endogenous steroid exposure, in a cohort of patients with chronic CSC (cCSC).

METHODS

Hair cortisol concentrations (HCC) were determined in 48 patients with cCSC and 230 population-based controls (Lifelines cohort study), not using exogenous corticosteroids.

RESULTS

Increased HCC (defined as >10.49 pg/mg) were present in 2 (4%) patients with cCSC and 13 (6%) controls. Mean HCC values were not different between patients and controls, and no difference in HCC was found between patients with active cCSC disease and patients with inactive disease. No correlation between HCC and urinary free cortisol (UFC) levels in patients with cCSC was found.

CONCLUSIONS

This study shows that HCC in patients with cCSC are not elevated compared to population-based controls, and no association between HCC and cCSC severity was found. This finding questions the previous suggestion that cCSC is associated with increased HPA axis activity. In line, HCC do not seem useful in monitoring cCSC disease activity.

Predicted Cellular and Molecular Actions of Lithium in the Treatment of Bipolar Disorder: An In Silico Study

BACKGROUND

Lithium remains the first-line treatment for bipolar disorder (BD), but patients respond to it variably. While a myriad of studies have attributed many genes and signaling pathways to lithium responsiveness, a comprehensive study with an integrated conclusion is still lacking.

OBJECTIVE

We aim to present an integrated mechanism for the therapeutic actions of lithium in BD.

METHODS

First, a list of lithium responsiveness-associated genes (LRAGs) was collected by searching in the literature. Thereafter, gene set enrichment analysis together with gene-gene interaction network analysis was performed, in order to find the cellular and molecular events related to the LRAGs.

RESULTS

Gene set enrichment analyses showed that the chromosomal regions 3p26, 4p21, 5q34 and 7p13 could be novel associated loci for lithium responsiveness in BD. Also, expression pattern analysis of the LRAGs showed their enrichment in adulthood stages and different cell lineages of brain, blood and immune system. Most of the LRAGs exhibited enriched expression in central parts of human brain, suggesting major contribution of these parts in lithium responsiveness. Beside the prediction of several biological processes and signaling pathways related to lithium responsiveness, an interaction network between these processes was constructed that was found to be regulated by a set of microRNAs. Proteins of the network were mainly classified as transcription factors and kinases, which also highlighted the crucial role of glycogen synthase kinase 3β (GSK3β) in lithium responsiveness.

CONCLUSIONS

The predicted cellular and molecular events in this study could be considered as mechanisms and also determinants of lithium responsiveness in BD.

Psychiatric symptoms and expression of glucocorticoid receptor gene in cocaine users: A longitudinal study

BACKGROUND

Chronic cocaine users (CU) display reduced peripheral expression of the glucocorticoid receptor gene (NR3C1), which is potentially involved in stress-related psychiatric symptoms frequently occurring in CU. However, it is unknown whether psychiatric symptoms and lower NR3C1 expression are related to each other and whether reduction of drug consumption reverse them.

METHOD

At baseline, NR3C1 mRNA expression was measured in 68 recreational CU, 30 dependent CU, and 68 stimulant-naïve controls. Additionally, the Revised Symptom Checklist (SCL-90R) and the Barratt Impulsiveness Scale (BIS) were assessed. At a one-year follow-up, the association between change in NR3C1 expression and psychiatric symptoms was examined in 48 stimulant-naïve controls, 19 CU who increased and 19 CU who decreased their consumption. At both test sessions, cocaine concentrations in hair samples were determined. Mixed-effects models were used to investigate how changes in drug use intensity affect severity of psychiatric symptoms and NR3C1 expression over time.

RESULTS

At baseline, recreational and dependent CU displayed elevated impulsivity and considerable symptom burden across most of the SCL-90R subscales. Time-group interaction effects were found for several impulsivity scores, SCL-90R Global Severity Index, Paranoid Thoughts, and Depression subscales as well as for NR3C1 expression. Pairwise comparisons showed that decreasing CU specifically improved in these SCL-90R subscales, while their NR3C1 expression was adapted. Finally, changes in NR3C1 expression were negatively correlated with changes in impulsivity but not SCL-90R scores.

CONCLUSION

Our findings suggest that NR3C1 expression changes and some psychiatric symptoms are reversible upon reduction of cocaine intake, thus favouring abstinence-oriented treatment approaches.

Normalized Cortisol Reactivity Predicts Future Neuropsychological Functioning in Children With Mild/Moderate Asthma

Cortisol reactivity to adrenocorticotropic hormone (ACTH) has been associated with neuropsychological processes including attention and memory in children with asthma. While cortisol reactivity to a psychological stressor is often considered a measure of current neuroendocrine functioning, this study examines the association of the cortisol reactivity and subsequent neuropsychological functioning. Using prospective data from the Childhood Asthma Management Program (CAMP), we explored the predictive ability of cortisol reactivity to ACTH and children's later attention and memory using traditional and an alternative cortisol reactivity (normalized cortisol) measures. Cortisol reactivity was assessed at study entry and 1-year follow-up, and neuropsychological functioning was assessed at 3-year follow-up. Cortisol reactivity was assessed through plasma cortisol concentrations collected at baseline (CORTBASELINE) and 30 min post-ACTH challenge (CORTPOST-A CTH). An alternative measure of cortisol reactivity was developed through post-ACTH stimulation cortisol, normalized by cortisol by baseline (CORTNORM -ACTH). CORT B ASELINE positively predicted year 3 attention, while CORTNORM -ACTH negatively predicted attention, suggesting convergence of cortisol variables in prediction of neuropsychological function. Year 1 CORTACTH positively predicted child memory at year 3; Year 1 CORTNORM-ACTH negatively predicted year 3 sustained attentions. These findings demonstrate that HPA reactivity, including the application of normalized cortisol reactivity, can predict subsequent neuropsychological functioning of children with mild to moderate asthma.

The Relationship Between Neuroimmunity and Bipolar Disorder: Mechanism and Translational Application

Neuroimmune system may be involved in the pathological process of bipolar disorder (BD), but the essential association is not fully understood. Accumulating evidence has shown that BD involves the activation of immune cells and the release of inflammatory substances in the central nerve system (CNS). Meanwhile, neuroimmune responses also interact with other hypothesis of the etiology of BD that are widely recognized, such as neurotransmitter systems, neuroendocrine systems, neurotrophic factors, and oxidative stress. Simultaneously, related genes and immune changes in peripheral blood vary with it. Overall, neuroimmunity may play an important role in the pathogenesis of BD, and the inflammatory cytokines, especially interleukin-6 and tumor necrosis factor-alpha, have potential value for the clinical diagnosis and prognosis of BD, as well as predicting the therapeutic effects of drugs. Large-scale studies are needed to extend the evidence on neuroimmunity in BD, and to examine its clinical value for applications such as early prediction and treatment.

Associations between fatigue, sleep disturbance and eating style in adults with type 2 diabetes: A correlational study

AIMS AND OBJECTIVES

To test the hypothesis that fatigue and sleep disturbance account for a significant amount of variation in eating styles among people with type 2 diabetes (T2D).

BACKGROUND

Healthy eating is an important component of diabetes self-care but remains a major challenge. In people with T2D, symptoms of fatigue and sleep disturbance are pervasive. However, there is limited understanding of whether fatigue and sleep disturbance are associated with eating style in people with T2D.

DESIGN

Correlational design.

METHODS

This study was reported following the STROBE checklist. Data were collected between February 2017 and January 2018. A convenience sample of 64 T2D adults completed the Three-Factor Eating Questionnaire-R18V2 to measure eating style (e.g., emotional eating, cognitive restraint and uncontrolled eating). Diabetes distress, fatigue and sleep disturbance were measured using validated questionnaires. Hierarchical regression analyses were performed.

RESULTS

Only age was a significant predictor (β = -0.344) of cognitive restraint. Participant demographics, psychological factor and health-related factors contribute significantly to the model predicting emotional eating, but only diabetes distress was a significant predictor (β = 0.433). Introducing fatigue and poor sleep quality explained an additional 12.0% of the variation in emotional eating. The final model explained 24.9% of the variation in emotional eating; both diabetes distress (β = 0.294) and fatigue (β = 0.360) were significant predictors.

CONCLUSION

There is a strong, independent relationship of fatigue and diabetes distress with emotional eating T2D patients. The effect of improving fatigue and diabetes distress on eating style should be explored.

RELEVANCE TO CLINICAL PRACTICE

In clinical practice, nurses are recommended to include a detailed assessment of fatigue and distress in patients with diabetes. Additional to the conventional nutrition therapy focusing on diet advice, eating style should also be incorporated in diet education by diabetes nurses.

Does Prenatal Stress Shape Postnatal Resilience? - An Epigenome-Wide Study on Violence and Mental Health in Humans

Stress during pregnancy widely associates with epigenetic changes and psychiatric problems during childhood. Animal studies, however, show that under specific postnatal conditions prenatal stress may have other, less detrimental consequences for the offspring. Here, we studied mental health and epigenome-wide DNA methylation in saliva following intimate partner violence (IPV) during pregnancy in São Gonçalo, a Brazilian city with high levels of violence. Not surprisingly, mothers exposed to pregnancy IPV expressed elevated depression, PTSD and anxiety symptoms. Children had similar psychiatric problems when they experienced maternal IPV after being born. More surprisingly, when maternal IPV occurred both during (prenatal) and after pregnancy these problems were absent. Following prenatal IPV, genomic sites in genes encoding the glucocorticoid receptor (NR3C1) and its repressor FKBP51 (FKBP5) were among the most differentially methylated and indicated an enhanced ability to terminate hormonal stress responses in prenatally stressed children. These children also showed more DNA methylation in heterochromatin-like regions, which previously has been associated with stress/disease resilience. A similar relationship was seen in prenatally stressed middle-eastern refugees of the same age as the São Gonçalo children but exposed to postnatal war-related violence. While our study is limited in location and sample size, it provides novel insights on how prenatal stress may epigenetically shape resilience in humans, possibly through interactions with the postnatal environment. This translates animal findings and emphasizes the importance to account for population differences when studying how early life gene–environment interactions affects mental health.

Methylation of the glucocorticoid receptor gene associated with depression in patients with acute coronary syndrome

OBJECTIVE

The present study investigated the longitudinal effects of NR3C1 1 F exon methylation on the risk of depression following ACS and treatment outcomes.

METHODS

In total, 969 patients admitted for recent ACS were recruited within 2 weeks of ACS; 711 of these patients were followed up at 1 year. Depressive disorder was diagnosed according to DSM-IV criteria and included prevalent depressive disorder at baseline and incident or persistent depressive disorder at follow-up based on depression status at the two examinations. Of the 378 baseline participants who were diagnosed with depression, 255 participated in a randomized double-blind placebo-controlled trial of escitalopram, while the remaining 123 were managed with the usual medical treatment for ACS.NR3C1 1 F exon methylation was measured using peripheral blood samples, and various demographic and clinical characteristics were assessed as covariates.

RESULTS

Higher NR3C1 1 F exon methylation levels were independently associated with prevalent depressive disorder at baseline but not with incident or persistent depressive disorder at follow-up based on logistic regression analyses adjusted for covariates. The effects of escitalopram on the remission of depressive symptoms was not influenced by NR3C1 1 F exon methylation status in ACS patients, but a placebo effect on the remission of depressive symptoms was observed, particularly in patients with lower methylation levels.

CONCLUSIONS

ACS patients with higher NR3C1 1 F exon methylation levels were at higher risk of developing depressive disorder within 2 weeks of ACS. Additionally, adequate antidepressant treatment may be effective for the remission of depressive symptoms regardless of NR3C1 1 F exon methylation status.

Epigenetic and Neurological Impairments Associated with Early Life Exposure to Persistent Organic Pollutants

The incidence of neurodevelopmental and neurodegenerative diseases worldwide has dramatically increased over the last decades. Although the aetiology remains uncertain, evidence is now growing that exposure to persistent organic pollutants during sensitive neurodevelopmental periods such as early life may be a strong risk factor, predisposing the individual to disease development later in life. Epidemiological studies have associated environmentally persistent organic pollutant exposure to brain disorders including neuropathies, cognitive, motor, and sensory impairments; neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD); and neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). In many ways, this expands the classical “Developmental Origins of Health and Disease” paradigm to include exposure to pollutants. This model has been refined over the years to give the current “three-hit” model that considers the individual's genetic factors as a first “hit.” It has an immediate interaction with the early-life exposome (including persistent organic pollutants) that can be considered to be a second “hit.” Together, these first two “hits” produce a quiescent or latent phenotype, most probably encoded in the epigenome, which has become susceptible to a third environmental “hit” in later life. It is only after the third “hit” that the increased risk of disease symptoms is crystallised. However, if the individual is exposed to a different environment in later life, they would be expected to remain healthy. In this review, we examine the effect of exposure to persistent organic pollutants and particulate matters in early life and the relationship to subsequent neurodevelopmental and neurodegenerative disorders. The roles of those environmental factors which may affect epigenetic DNA methylation and therefore influence normal neurodevelopment are then evaluated.

Genetic variation in the glucocorticoid receptor and psychopathology after dexamethasone administration in cardiac surgery patients

The glucocorticoid receptor (GR) agonist dexamethasone is frequently used for its anti-inflammatory properties. We recently showed that a single high-dose of dexamethasone had long-lasting protective effects on the development of psychopathology after cardiac surgery and postoperative intensive care unit stay. In this study, we investigated whether common genetic variation in the hypothalamic-pituitary-adrenal (HPA)-axis would influence the susceptibility for PTSD and depression after dexamethasone administration. Participants (n = 996) of the Dexamethasone for Cardiac Surgery (DECS) randomized clinical trial were followed after receiving a single high intraoperative dose of dexamethasone (1 mg/kg), a GR agonist, or placebo. PTSD and depressive symptoms were assessed up to four years after cardiac surgery. We focused primarily on five common single nucleotide polymorphisms (SNPs) in the glucocorticoid receptor (GR). Secondarily, we comprehensively assessed common genetic variation in the FK506 binding protein (FKBP5) and the mineralocorticoid receptor (MR). The protective effects of dexamethasone on postoperative PTSD symptoms were dependent on the GR polymorphisms rs41423247 (p = .009), rs10052957 (p = .003), and rs6189 (p = .002), but not on rs6195 (p = .025) or rs6198, (p = .026) after Bonferroni correction. No genotype-dependent effects were found for postoperative depressive symptoms. Also, no associations of FKBP5 and MR polymorphisms were found on PTSD and depression outcomes. Protective effects of dexamethasone on PTSD symptoms after cardiac surgery and ICU stay seem to depend on common genetic variation in its target receptor, the GR. These effects indicate that pre-operative genetic screening could potentially help in stratifying patients for their vulnerability for developing PTSD symptoms after surgery.

Hsp90 and FKBP51: complex regulators of psychiatric diseases

Mood disorders affect nearly a quarter of the world's population. Therefore, understanding the molecular mechanisms underlying these conditions is of great importance. FK-506 binding protein 5 (FKBP5) encodes the FKBP51 protein, a heat shock protein 90 kDa (Hsp90) co-chaperone, and is a risk factor for several affective disorders. FKBP51, in coordination with Hsp90, regulates glucocorticoid receptor (GR) activity via a short negative feedback loop. This signalling pathway rapidly restores homeostasis in the hypothalamic-pituitary-adrenal (HPA) axis following stress. Expression of FKBP5 increases with age through reduced DNA methylation. High levels of FKBP51 are linked to GR resistance and reduced stress coping behaviour. Moreover, common allelic variants in the FKBP5 gene are associated with increased risk of developing affective disorders like anxiety, depression and post-traumatic stress disorder (PTSD). This review highlights the current understanding of the Hsp90 co-chaperone, FKBP5, in disease from both human and animal studies. In addition, FKBP5 genetic implications in the clinic involving life stress exposure, gender differences and treatment outcomes are discussed.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.

Longitudinal associations between glucocorticoid receptor methylation and late-life depression

It has been suggested that hypothalamus-pituitary-adrenal (HPA) axis dysregulation plays a role in the etiology of depression. HPA axis function is mediated by glucocorticoid receptors (GRs), which are influenced by epigenetic mechanisms (DNA methylation). The association between the DNA methylation of the GR gene (nuclear receptor subfamily 3, group C, member 1; NR3C1) and late-life depression as well as the role of NR3C1 methylation in the prediction of the incidence of depression have not yet been investigated. Therefore, we examined the independent and longitudinal effects of the methylation of three CpG sites in exon 1_F of NR3C1 on late-life depression using peripheral blood. In total, 732 Korean community residents aged ≥65 years were assessed; 521 individuals in this group without depression at baseline were followed 2 years later. The Geriatric Mental State Schedule was used to identify depression, and demographic and clinical covariates were evaluated. The effects of NR3C1 methylation (the individual methylation status of three CpG sites and their average values) on current and follow-up depression were calculated using a multivariate logistic regression model. Higher NR3C1 methylation levels at CpG 2 and 3 and the average methylation value were independently associated with the prevalence of depression at baseline. Additionally, a higher NR3C1 methylation level at CpG 2 was associated with depression incidence 2 years later in this population. These findings suggest an association between the methylation of NR3C1 exon 1_F, especially at CpG 2, and depression later in life.

Influence of CRHR1 Polymorphisms and Childhood Abuse on Suicide Attempts in Affective Disorders: A GxE Approach

Background: Previous studies have shown that the hypothalamus-pituitary-adrenal-axis (HPA-axis) is closely involved in the development of affective disorders. Given that early life events are also linked to dysregulation of the same system, there might be an association between childhood adversities and suicidal behavior in affective disorders, moderated by HPA-axis genes. We aimed to investigate a potential association between childhood trauma and previous suicide attempts in affective disorder patients, moderated by variants of the corticotropin-releasing hormone receptor 1 (CRHR1) gene. Methods: The current pilot study is part of an ongoing study on suicidal behavior in affective disorders (VieSAD). Two hundred fifty eight Caucasian affective disorder patients were assessed at the Department of Psychiatry and Psychotherapy of the Medical University Vienna and the Karl Landsteiner University for Health and Science. An assemblage of psychiatric interviews was performed (e.g., SCAN, HAMD, SBQ-R, CTQ) and DNA samples of peripheral blood cells were genotyped with TaqMan® SNP Genotyping Assays (rs7209436, rs4792887, rs110402, rs242924, and rs242939). Results: Neither genetic, nor haplotypic associations between CRHR1 polymorphisms and previous suicide attempts could be established for the present sample. Using a binary logistic regression model, significant gene-environment-interactions were found for the single nucleotide polymorphisms (SNPs) rs7209436 and rs110402, reflecting the impact of childhood trauma and CRHR1 polymorphisms on previous suicide attempts. Limitations: A larger sample size will be required to ultimately elucidate the link between childhood trauma and the HPA axis in suicidal behavior. Conclusion: This pilot study presents promising gene-environment-interaction findings in affective disorder patients with a history of suicide attempts.

Exposure to Ambient Air Particles Increases the Risk of Mental Disorder: Findings from a Natural Experiment in Beijing

Epidemiology studies indicated that air pollution has been associated with adverse neurological effects in human. Moreover, the secretion of glucocorticoid (GC) affects the mood regulation, and the negative feedback of hippocampal glucocorticoid receptors (GR) inhibits the GC secretion. Meanwhile, the over secretion of GC can interfere the immune system and induce neurotoxicity. In the present study, the human test showed that the secretion of the cortisol in plasma was elevated after exposure in heavy air pollution. In the mouse model, we found that breathing the highly polluted air resulted in the negative responses of the mood-related behavioral tests and morphology of hippocampus, as well as the over secretion of GC in plasma, down regulation of GR, and up-regulation of cytokine and chemokine in the hippocampus. When considering the interrelated trends between the hippocampal GR, inflammatory factors, and plasmatic GC, we speculated that PM_2.5 exposure could lead to the increased secretion of GC in plasma by decreasing the expression of GR in hippocampus, which activated the inflammation response, and finally induced neurotoxicity, suggesting that PM_2.5 exposure negatively affects mood regulation. When combined with the results of the human test, it indicated that exposure to ambient air particles increased the risk of mental disorder.

The role of genetic variation in the glucocorticoid receptor (NR3C1) and mineralocorticoid receptor (NR3C2) in the association between cortisol response and cognition under acute stress

Although HPA - axis reactivity has repeatedly been related to cognitive functioning, ambiguity remains regarding the direction of the effect, i.e. whether it benefits or impairs functioning. Genetic factors that contribute to HPA - axis reactivity on the one hand and to cognitive functioning on the other could therefore help clarify the association between stress and cognition. We genotyped 10 single nucleotide polymorphisms (SNPs) on the NR3C1 gene (rs10482682, rs33389, rs10482633, rs10515522, rs2963156, rs4128428, rs9324918, rs41423247, rs6189, rs10052957) coding for the glucocorticoid receptor (GR) and 4 SNPs on the NR3C2 gene (rs6810951, rs4635799, rs11099695, rs2070950) coding for the mineralocorticoid receptor (MR) and required N=126 healthy males to perform tasks assessing attention and reasoning before and after experiencing an acute laboratory stressor (the Socially Evaluated Cold Pressor Test, SECPT). Haplotype analyses revealed significant effects of NR3C1 (p=0.011) and NR3C2 (p=0.034) on cortisol stress response. NR3C2 also influenced attentional performance via an interaction with stress-induced cortisol response (p<0.001). Neither NR3C1 haplotype nor NR3C2 haplotype was associated with reasoning abilities. Results suggest that the association between stress induced cortisol reactivity and cognition strongly depends on genetic variation. The idea of an optimal arousal level depending on stress reactivity and genetic disposition is discussed.

Application of Proteomic Techniques for Improved Stratification and Treatment of Schizophrenia Patients

For major psychiatric disorders such as schizophrenia, there have been shortcomings in the translation of scientific findings into new treatments and this has led to diminished interest for large pharmaceutical companies. This chapter describes how incorporation of proteomic approaches into the clinical pipeline can lead to identification and implementation of biomarker tests for improved patient characterization, prediction of treatment response and monitoring treatment effects to help revitalize efforts in this important area. In addition, the construction of specific biomarker tests for disease prediction should smooth the progress of early intervention strategies which, in turn, may help to slow disease onset or progression. Finally, the development of purpose-built biomarker tests using lab-on-a-chip platforms with smartphone readouts will help to shift the diagnosis and treatment of this major psychiatric disorder into point-of-care settings for increased effectiveness and improved patient outcomes.

The Cortisol Awakening Response and Depressive Symptomatology: The Moderating Role of Sleep and Gender

The association between depression and the cortisol awakening response (CAR) has been widely examined, yet the results are mixed and factors responsible for such inconsistencies are poorly understood. The current study investigated whether the link between depressive symptomatology and CAR varied as a function of two such factors: sleep and gender. The sample included 58 young adults (30 females; M_age  = 18.7; SD_age  = 0.91). Participants completed the Beck Depression Inventory as well as the Consensus Sleep Diary to assess depressive symptomatology and daily sleep patterns, respectively. Participants also provided four salivary cortisol samples (0, 30, 45 and 60 min after awakening) during two consecutive weekdays. Results demonstrated that greater depressive symptoms were associated with a greater CAR but only when depressive symptoms were linked to a shorter sleep time. In addition, gender significantly moderated the association between depressive symptoms and CAR. While greater depressive symptoms were associated with an elevated CAR among females, they were associated with a blunted CAR among males. These findings provide some insight into potential mechanisms linking depressive symptomatology and CAR, and suggest that future studies examining CAR as a biomarker of depression should account for differences in sleep and gender. Copyright © 2016 John Wiley & Sons, Ltd.

Dynamic expression of FKBP5 in the medial prefrontal cortex regulates resiliency to conditioned fear

The factors influencing resiliency to the development of post-traumatic stress disorder (PTSD) remain to be elucidated. Clinical studies associate PTSD with polymorphisms of the FK506 binding protein 5 (FKBP5). However, it is unclear whether changes in FKBP5 expression alone could produce resiliency or susceptibility to PTSD-like symptoms. In this study, we used rats as an animal model to examine whether FKBP5 in the infralimbic (IL) or prelimbic (PL) medial prefrontal cortex regulates fear conditioning or extinction. First, we examined FKBP5 expression in IL and PL during fear conditioning or extinction. In contrast to the stable expression of FKBP5 seen in PL, FKBP5 expression in IL increased after fear conditioning and remained elevated even after extinction suggesting that IL FKBP5 levels may modulate fear conditioning or extinction. Consistent with this possibility, reducing basal FKBP5 expression via local infusion of FKBP5–shRNA into IL reduced fear conditioning. Furthermore, reducing IL FKBP5, after consolidation of the fear memory, enhanced extinction memory indicating that IL FKBP5 opposed formation of the extinction memory. Our findings demonstrate that lowering FKBP5 expression in IL is sufficient to both reduce fear acquisition and enhance extinction, and suggest that lower expression of FKBP5 in the ventral medial prefrontal cortex could contribute to resiliency to PTSD.

The sex-dependent role of the glucocorticoid receptor in depression: variations in the NR3C1 gene are associated with major depressive disorder in women but not in men

Genetic variations in the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR) have been associated with maladaptive stress responses and major depressive disorder (MDD). In a case-control study design, we examined whether single nucleotide polymorphisms (SNPs) and haploid genotype (haplotype) associations of MR gene NR3C2, GR gene NR3C1 and genes of GR chaperone molecules FK506 binding protein 5 (FKBP5) and corticotrophin-releasing hormone receptor 1 (CRHR1) differed between healthy subjects (n = 634) and inpatients with major depressive disorder (n = 412). All analyses were conducted for women and men separately. After conservative correction of Type-I-error to obtain reliable p values, one SNP in the NR3C1 gene, namely rs6195, showed a significant association with the presence of a major depression (p = 0.048) in females. In contrast, NR3C2, FKBP5 and CRHR1 polymorphisms were not significantly associated with MDD. No haplotype effects could be identified. Our results support the notion of an association between variants of GR-related genes in women and the pathophysiology of depression: females suffering from MDD showed a more than three times higher frequency of the T/C polymorphism compared to controls, which thus seems to increase the vulnerability to depression in females.

Psychological and endocrine factors and pain after mastectomy

BACKGROUND

This prospective study was designed to examine the associations of demographic, clinical, psychological and neuroendocrine factors with acute and chronic post-operative pain following partial mastectomy.

METHODS

Sixty-four female patients scheduled for partial mastectomy were enrolled. Pre-operative anxiety/depression was assessed, using the Hospital Anxiety and Depression Scale (HADS). Pre-operative 24-h urinary cortisol levels were measured 2 days before surgery. Post-operative pain was examined using a visual analog scale (VAS) for acute pain on 0-2 post-operative day (POD), and a short-form McGill Pain Questionnaire for chronic pain at 6 months after surgery. In the last 29 subjects, post-operative 24-h urinary cortisol levels were also measured on 0 POD and were subjected to correlation analysis.

RESULTS

Multivariate logistic regression analysis revealed that lower pre-operative cortisol secretion and greater pre-operative anxiety were significantly associated with an increased risk of moderate to severe acute post-operative pain [Odds Ratio (95% Confidence Interval); 0.96 (0.92-0.98), and 1.24 (1.04-1.54)], and that patients with greater pre-operative anxiety and moderate to severe acute pain were more likely to develop chronic post-operative pain [OR (95% CI); 1.63 (1.23-2.40), and 5.07 (1.30-24.6)]. Correlational analysis demonstrated that the post-operative cortisol level was inversely correlated with pre-operative anxiety and the intensity of acute post-operative pain (r = -0.40, p < 0.05, and r = -0.50, p < 0.01), but not with the intensity of chronic pain.

CONCLUSIONS

This study confirms that pre-operative anxiety is associated with both acute and chronic post-operative pain after partial mastectomy. It also suggests that lower perioperative cortisol secretion might be associated with greater acute post-operative pain.

SIGNIFICANCE

Although the associations between psychological stress/stress hormone levels and chronic post-operative pain remain to be determined, pre-operative psychological stress and perioperative cortisol levels are correlated with acute post-operative pain.

Glucocorticoid receptor gene polymorphisms in hereditary angioedema with C1-inhibitor deficiency

BACKGROUND

Hereditary angioedema caused by C1-inhibitor deficiency (C1-INH-HAE) is a rare, autosomal dominant disorder. C1-INH-HAE is characterized by edema-formation, which may occur in response to stress. The individual's response to stress stimuli is partly genetically determined. Activation of the hypothalamic-pituitary-adrenal axis results in the release of cortisol. In turn, the secreted gluco- and mineralocorticoids affect the metabolism, as well as the cardiovascular and immune systems. We hypothesized that changes in serum cortisol level and polymorphisms of the glucocorticoid receptor (GR) modify the individual sensitivity to stressor stimuli of C1-INH-HAE patients.

RESULTS

We compared the response to stress with Rahe's Brief Stress and Coping Inventory of 43 C1-INH-HAE patients, 18 angioedema patients and 13 healthy controls. 139 C1-INH-HAE patients and 160 healthy controls were genotyped for glucocorticoid receptor polymorphisms BclI, N363S and A3669G. Serum cortisol levels were determined during attacks and during symptom-free periods in 36 C1-INH-HAE patients. The relationships between clinical, laboratory data and GR SNPs (Single Nucleotide Polymorphisms) were assessed using ANOVA. C1-INH-HAE patients have decreased coping capabilities compared to healthy controls. Cortisol levels were significantly higher during attacks than in symptom-free periods (p = 0.004). The magnitude of the elevation of cortisol levels did not show a significant correlation with any clinical or laboratory data. Among the C1-INH-HAE patients, the carriers of the A3669G allele had significantly lower cortisol levels, and increased body mass index compared with non-carriers.

CONCLUSIONS

The higher cortisol level observed during attacks may reflect the effect of a stressful situation (such as of the attack itself), on the patients' neuroendocrine system. In A3669G carriers, the lower cortisol levels might reflect altered feedback to the hypothalamic-pituitary-adrenal axis, due to decreased sensitivity to glucocorticoids.

The Application of Multiplex Biomarker Techniques for Improved Stratification and Treatment of Schizophrenia Patients

In the case of major psychiatric disorders such as schizophrenia, shortcomings in the conversion of scientific discoveries into newer and safer treatment options has led to a loss of confidence and precipitated a crisis for large pharmaceutical companies. This chapter describes how incorporation of multiplex biomarker approaches into the clinical pipeline can lead to better patient characterization, delivery of novel treatment approaches and help to renew efforts in this important area. The development of specific biomarker test panels for disease prediction should facilitate early intervention strategies, which may help to slow disease development or progression. Furthermore, the development of such tests using lab-on-a-chip and smartphone platforms will help to shift diagnosis and treatment of this major disorder into a point-of-care setting for improved patient outcomes.

A users guide to HPA axis research

Glucocorticoid hormones (cortisol and corticosterone - CORT) are the effector hormones of the hypothalamic-pituitary-adrenal (HPA) axis neuroendocrine system. CORT is a systemic intercellular signal whose level predictably varies with time of day and dynamically increases with environmental and psychological stressors. This hormonal signal is utilized by virtually every cell and physiological system of the body to optimize performance according to circadian, environmental and physiological demands. Disturbances in normal HPA axis activity profiles are associated with a wide variety of physiological and mental health disorders. Despite numerous studies to date that have identified molecular, cellular and systems-level glucocorticoid actions, new glucocorticoid actions and clinical status associations continue to be revealed at a brisk pace in the scientific literature. However, the breadth of investigators working in this area poses distinct challenges in ensuring common practices across investigators, and a full appreciation for the complexity of a system that is often reduced to a single dependent measure. This Users Guide is intended to provide a fundamental overview of conceptual, technical and practical knowledge that will assist individuals who engage in and evaluate HPA axis research. We begin with examination of the anatomical and hormonal components of the HPA axis and their physiological range of operation. We then examine strategies and best practices for systematic manipulation and accurate measurement of HPA axis activity. We feature use of experimental methods that will assist with better understanding of CORT's physiological actions, especially as those actions impact subsequent brain function. This research approach is instrumental for determining the mechanisms by which alterations of HPA axis function may contribute to pathophysiology.

The Very Low-Dose Dexamethasone Suppression Test in the General Population: A Cross-Sectional Study

Determinants of the hypothalamic-pituitary-adrenal (HPA) axis functioning are increasingly explored in population-based studies. However, functional tests measuring the negative feedback of the HPA axis cannot easily be implemented into large observational studies. Furthermore, high doses of dexamethasone often completely suppress the HPA axis in healthy persons. This study aimed to detect the effects of the health, lifestyle and sociodemographic factors, psychiatric problems and cognitive functions on the negative feedback of the HPA axis using a very low-dose (0.25 mg) dexamethasone suppression test (DST).We evaluated the associations of several determinants with the saliva cortisol concentrations after dexamethasone intake in a confounder-adjusted model also corrected for baseline saliva cortisol concentrations in the Rotterdam Study, a large population-based study (N = 1822). We found that female sex, low income, lack of exercise, instrumental disability and smoking were all independently associated with stronger suppression of the HPA axis. Even though there were no linear associations between psychiatric measures and cortisol suppression, we found that depressive symptoms and anxiety disorders were more common in persons with non-suppression of cortisol. Conversely, psychotropic medication use was related to enhanced suppression of cortisol after DST. In this large study, we found that female gender, low socioeconomic status and poor health were all related to suppression of the HPA axis. Non-linear associations were detected between the suppression of the HPA axis and common psychiatric disorders in community-dwelling persons.

Stress and Depression: a Crucial Role of the Mineralocorticoid Receptor

Cortisol and corticosterone act on the appraisal process, which comprises the selection of an appropriate coping style and the encoding of the experience for storage in the memory. This action exerted by the stress hormones is mediated by mineralocorticoid receptors (MRs), which are expressed abundantly in the limbic circuitry, particularly in the hippocampus. Limbic MR is down-regulated by chronic stress and during depression but induced by antidepressants. Increased MR activity inhibits hypothalamic-pituitary-adrenal axis activity, promotes slow wave sleep, reduces anxiety and switches circuit connectivity to support coping. Cortisol and emotion-cognition are affected by MR gene haplotypes based on rs5522 and rs2070951. Haplotype 1 (GA) moderates the effects of (early) life stressors, reproductive cycle and oral contraceptives. MR haplotype 2 (CA) is a gain of function variant that protects females against depression by association with an optimistic, resilient phenotype. Activation of MR therefore may offer a target for alleviating depression and cognitive dysfunction. Accordingly, the MR agonist fludrocortisone was found to enhance the efficacy of antidepressants and to improve memory and executive functions in young depressed patients. In conclusion, CORT coordinates via MR the networks underlying how an individual copes with stress, and this action is complemented by the widely distributed lower affinity glucocorticoid receptor (GR) involved in the subsequent management of stress adaptation. In this MR:GR regulation, the MR is an important target for promoting resilience.

Childhood maltreatment and methylation of FK506 binding protein 5 gene (FKBP5)

A growing body of evidence suggests that alterations of the stress response system may be a mechanism by which childhood maltreatment alters risk for psychopathology. FK506 binding protein 51 (FKBP5) binds to the glucocorticoid receptor and alters its ability to respond to stress signaling. The aim of the present study was to examine methylation of the FKBP5 gene (FKBP5), and the role of an FKBP5 genetic variant, in relation to childhood maltreatment in a sample of impoverished preschool-aged children. One hundred seventy-four families participated in this study, including 69 with child welfare documentation of moderate to severe maltreatment in the past 6 months. The children, who ranged in age from 3 to 5 years, were racially and ethnically diverse. Structured record review and interviews in the home were used to assess a history of maltreatment, other traumas, and contextual life stressors; and a composite variable assessed the number exposures to these adversities. Methylation of two sites in intron 7 of FKBP5 was measured via sodium bisulfite pyrosequencing. Maltreated children had significantly lower levels of methylation at both CpG sites (p < .05). Lifetime contextual stress exposure showed a trend for lower levels of methylation at one of the sites, and a trend for an interaction with the FKBP5 polymorphism. A composite adversity variable was associated with lower levels of methylation at one of the sites as well (p < .05). FKBP5 alters glucocorticoid receptor responsiveness, and FKBP5 gene methylation may be a mechanism of the biobehavioral effects of adverse exposures in young children.

Allelic variation in CRHR1 predisposes to panic disorder: evidence for biased fear processing

Corticotropin-releasing hormone (CRH) is a major regulator of the hypothalamic-pituitary-adrenal axis. Binding to its receptor CRHR1 triggers the downstream release of the stress response-regulating hormone cortisol. Biochemical, behavioral and genetic studies revealed CRHR1 as a possible candidate gene for mood and anxiety disorders. Here we aimed to evaluate CRHR1 as a risk factor for panic disorder (PD). Allelic variation of CRHR1 was captured by 9 single-nucleotide polymorphisms (SNPs), which were genotyped in 531 matched case/control pairs. Four SNPs were found to be associated with PD, in at least one sub-sample. The minor allele of rs17689918 was found to significantly increase risk for PD in females after Bonferroni correction and furthermore decreased CRHR1 mRNA expression in human forebrains and amygdalae. When investigating neural correlates underlying this association in patients with PD using functional magnetic resonance imaging, risk allele carriers of rs17689918 showed aberrant differential conditioning predominantly in the bilateral prefrontal cortex and safety signal processing in the amygdalae, arguing for predominant generalization of fear and hence anxious apprehension. Additionally, the risk allele of rs17689918 led to less flight behavior during fear-provoking situations but rather increased anxious apprehension and went along with increased anxiety sensitivity. Thus reduced gene expression driven by CRHR1 risk allele leads to a phenotype characterized by fear sensitization and hence sustained fear. These results strengthen the role of CRHR1 in PD and clarify the mechanisms by which genetic variation in CRHR1 is linked to this disorder.

Sequencing analysis of the human glucocorticoid receptor (NR3C1) gene in multiple sclerosis patients

Various specific human glucocorticoid receptor (NR3C1) gene polymorphisms have been described in multiple sclerosis (MS) patients and correlated with disease progression, susceptibility and aggressiveness. Herein, we investigated the presence of gene alterations in the entire coding region of the NR3C1 in MS patients of variable clinical status (CIS, RRMS and SPMS) and the association(s) of these alterations with severity of disease (EDSS), response to glucocorticoid (GC) treatment and clinical improvement. Sixty Caucasian Greek MS patients were included. Sequencing the coding sequences and intron-exon boundaries of the NR3C1 did not reveal the presence of mutation(s) in any of the MS patients. Three previously described polymorphisms were detected: p.N363S (rs6195), p.N766N (rs6196) and c.1469-16G>T (rs6188). None of the identified alleles/genotypes were found to be associated with the severity of disease, response to glucocorticoids and disease subtypes. Known polymorphism, such as ER22/23EK that has been previously detected in MS patients, was not detected. There is a considerable ethnicity-related variation in the frequency of the NR3C1 polymorphisms. Although a genetic basis of the glucocorticoid sensitivity exists in healthy population, in the presence of chronic inflammation and abundance of cytokines--such in MS patients--other factors appear to play a more important role in GC sensitivity.

Sex differences in the outcome of juvenile social isolation on HPA axis function in rats

Women are more likely than men to suffer from anxiety disorders and major depression. These disorders share hyperresponsiveness to stress as an etiological factor. Thus, sex differences in brain arousal systems and their regulation by chronic stress may account for the increased vulnerability to these disorders in women. Social isolation is a model of early life stress that results in neurobiological alterations leading to increased anxiety-like and depressive-like behaviors. Here we investigated the sex difference in the effects of post-weaning social isolation on acute stress sensitivity and behavior in rats. In both sexes, social isolation at weaning reduced basal levels of the neuroactive steroid allopregnanolone in the brain and of corticosterone in plasma. Moreover, acute stress increased plasma corticosterone levels in both group-housed and socially isolated male and female rats; however this effect was greater in male than female rats subjected to social isolation. Intriguingly, group-housed female rats showed no change in plasma and brain levels of allopregnanolone after acute foot-shock stress. The absence of stress-induced effects on allopregnanolone synthesis might be due to the physiologically higher levels of this hormone in females vs. males. Accordingly, increasing allopregnanolone levels in male rats blunted the response to foot-shock stress in these animals. Socially isolated male, but not female, rats also display depressive-like behavior and increased hippocampal brain-derived neurotrophic factor (BDNF). The ovarian steroids could "buffer" the effect of this adverse experience in females on these parameters. Finally, the dexamethasone (DEX) suppression test indicated that the chronic stress associated with social isolation impairs feedback inhibition in both sexes in which an increase in the abundance of glucocorticoid receptors (GRs) in the hippocampus was found. Altogether, these results demonstrate that social isolation affects neuroendocrine reactivity to stress, plasticity and emotionality in a sexually dimorphic manner.

The cardiovascular and hypothalamus-pituitary-adrenal axis response to stress is controlled by glucocorticoid receptor sequence variants and promoter methylation

BACKGROUND

Gender, genetic makeup, and prior experience interact to determine physiological responses to an external perceived stressor. Here, we investigated the contribution of both genetic variants and promoter methylation of the NR3C1 (glucocorticoid receptor) gene to the cardiovascular and hypothalamus-pituitary-adrenal (HPA) axis response to the socially evaluated cold pressor test (seCPT).

RESULTS

Two hundred thirty-two healthy participants were recruited and underwent the experiment. They were randomly assigned to either the seCPT group (cold water) or a control group (warm water). The seCPT group had a clear stress reaction; salivary cortisol levels and peak systolic and diastolic blood pressure all increased significantly compared to the control group. GR genotype (TthIIII, NR3C1-I, 1H, E22E, R23K, BclI and 9beta) and methylation data were obtained from 218 participants. Haplotypes were built from the GR genotypes, and haplotype 2 (minor allele of BclI) carriers had a higher cortisol response to the seCPT in comparison to non-carriers (20.77 ± 13.22; 14.99 ± 8.42; p = 0.034), as well as independently of the experimental manipulation, higher baseline heart rate (72.44 ± 10.99; 68.74 ± 9.79; p = 0.022) and blood pressure (115.81 ± 10.47; 111.61 ± 10.74; p = 0.048). Average methylation levels throughout promoter 1F and 1H were low (2.76 and 1.69 %, respectively), but there was a strong correlation between individual CpGs and the distance separating them (Pearson's correlation r = 0.725, p = 3.03 × 10(-26)). Higher promoter-wide methylation levels were associated with decreased baseline blood pressure, and when incorporated into a linear mixed effect model significantly predicted lower systolic and diastolic blood pressure evolution over time in response to the experimental manipulation. The underlying genotype significantly predicted methylation levels; particularly, the homozygous BclI minor allele was associated with higher methylation in promoter 1H (p = 0.042).

CONCLUSIONS

This is one of the first studies linking epigenetic modifications of the GR promoter, receptor genotype and physiological measures of the stress response. At baseline, there were clear genetic and epigenetic effects on blood pressure. The seCPT induced a strong cardiovascular and HPA axis response, and both systems were affected by the functional genetic variants, although methylation also predicted blood pressure reactivity. The return to baseline was predominantly influenced by the genomic sequence. Overall, the physiological response to the seCPT is controlled by an exquisite mix of genetic and epigenetic factors.

Emotional attentional control predicts changes in diurnal cortisol secretion following exposure to a prolonged psychosocial stressor

Hypothalamic-pituitary-adrenal (HPA) axis irregularities have been associated with several psychological disorders. Hence, the identification of individual difference variables that predict variations in HPA-axis activity represents an important challenge for psychiatric research. We investigated whether self-reported attentional control in emotionally demanding situations prospectively predicted changes in diurnal salivary cortisol secretion following exposure to a prolonged psychosocial stressor. Low ability to voluntarily control attention has previously been associated with anxiety and depressive symptomatology. Attentional control was assessed using the Emotional Attentional Control Scale. In students who were preparing for academic examination, salivary cortisol was assessed before (time 1) and after (time 2) examination. Results showed that lower levels of self-reported emotional attentional control at time 1 (N=90) predicted higher absolute diurnal cortisol secretion and a slower decline in cortisol throughout the day at time 2 (N=71). Difficulty controlling attention during emotional experiences may lead to chronic HPA-axis hyperactivity after prolonged exposure to stress. These results indicate that screening for individual differences may foster prediction of HPA-axis disturbances, paving the way for targeted disorder prevention.

Early life trauma, depression and the glucocorticoid receptor gene--an epigenetic perspective

BACKGROUND

Hopes to identify genetic susceptibility loci accounting for the heritability seen in unipolar depression have not been fully realized. Family history remains the 'gold standard' for both risk stratification and prognosis in complex phenotypes such as depression. Meanwhile, the physiological mechanisms underlying life-event triggers for depression remain opaque. Epigenetics, comprising heritable changes in gene expression other than alterations of the nucleotide sequence, may offer a way to deepen our understanding of the aetiology and pathophysiology of unipolar depression and optimize treatments. A heuristic target for exploring the relevance of epigenetic changes in unipolar depression is the hypothalamic-pituitary-adrenal (HPA) axis. The glucocorticoid receptor (GR) gene (NR3C1) has been found to be susceptible to epigenetic modification, specifically DNA methylation, in the context of environmental stress such as early life trauma, which is an established risk for depression later in life.

METHOD

In this paper we discuss the progress that has been made by studies that have investigated the relationship between depression, early trauma, the HPA axis and the NR3C1 gene. Difficulties with the design of these studies are also explored.

RESULTS

Future efforts will need to comprehensively address epigenetic natural histories at the population, tissue, cell and gene levels. The complex interactions between the epigenome, genome and environment, as well as ongoing nosological difficulties, also pose significant challenges.

CONCLUSIONS

The work that has been done so far is nevertheless encouraging and suggests potential mechanistic and biomarker roles for differential DNA methylation patterns in NR3C1 as well as novel therapeutic targets.

Inflammation as a neurobiological substrate of cognitive impairment in bipolar disorder: Evidence, pathophysiology and treatment implications

BACKGROUND

Bipolar disorder (BD) has been associated with cognitive impairment during depressed, manic and euthymic periods. Inflammation has been shown to be involved in the pathophysiology of BD and cognitive impairment.

METHODS

For this systematic review, the MEDLINE/PubMed, Embase, Google Scholar and ClinicalTrials.gov databases were searched for relevant articles assessing the association between cognitive function and inflammatory markers in BD subjects. A discussion of potential mechanisms and therapeutic implications is also included to provide further context to the subject matter.

RESULTS

Eight studies, including a total of 555 BD subjects, assessing the association between cognitive function and inflammatory markers were identified. Cognitive dysfunction was associated with elevated levels of pro-inflammatory markers YKL40, IL-6, sCD40L, IL-1Ra, hsCRP and TNF-α. Mechanistically, elevation in inflammatory cytokines alters monoamine levels leading to cognitive and affective dysfunction. Neuro-inflammation, manifesting as microglial activation, leads to increased oxidative stress, pathologic synaptic pruning and impaired neuroplasticity in key brain regions sub-serving mood and cognition. Immune dysfunction also activates the hypothalamic-pituitary-adrenal (HPA) axis leading to hypercortisolemia and metabolic dysfunction, further promoting neuronal dysfunction. Anti-inflammatory agents are therefore currently being investigated in the treatment of BD and appear to exert an antidepressant effect; however, cognitive outcomes have yet to be reported.

CONCLUSION

Several studies suggest that immune dysfunction is associated with cognitive impairment in BD. Several neurobiological pathways have been identified whereby immune dysfunction may promote cognitive impairment in BD. Future investigations of anti-inflammatory agents targeting cognitive function as a treatment outcome are merited.

High cortisol in 5-year-old children causes loss of DNA methylation in SINE retrotransposons: a possible role for ZNF263 in stress-related diseases

Background

Childhood stress leads to increased risk of many adult diseases, such as major depression and cardiovascular disease. Studies show that adults with experienced childhood stress have specific epigenetic changes, but to understand the pathways that lead to disease, we also need to study the epigenetic link prospectively in children.

Results

Here, we studied a homogenous group of 48 5-year-old children. By combining hair cortisol measurements (a well-documented biomarker for chronic stress), with whole-genome DNA-methylation sequencing, we show that high cortisol associates with a genome-wide decrease in DNA methylation and targets short interspersed nuclear elements (SINEs; a type of retrotransposon) and genes important for calcium transport: phenomena commonly affected in stress-related diseases and in biological aging. More importantly, we identify a zinc-finger transcription factor, ZNF263, whose binding sites where highly overrepresented in regions experiencing methylation loss. This type of zinc-finger protein has previously shown to be involved in the defense against retrotransposons.

Conclusions

Our results show that stress in preschool children leads to changes in DNA methylation similar to those seen in biological aging. We suggest that this may affect future disease susceptibility by alterations in the epigenetic mechanisms that keep retrotransposons dormant. Future treatments for stress- and age-related diseases may therefore seek to target zinc-finger proteins that epigenetically control retrotransposon reactivation, such as ZNF263.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0123-z) contains supplementary material, which is available to authorized users.

Association of fatigue with emotional-eating behavior and the response to mental stress in food intake in a young adult population

Fatigue is a common complaint among young adults. We investigated whether eating behaviors are associated with fatigue in this population. The participants consisted of 117 healthy students attending Osaka City University. They completed questionnaires assessing fatigue and eating behaviors. To identify the factors associated with the prevalence of fatigue, multivariate logistic regression analysis adjusted for gender was performed. The Emotional Eating subscale score of the Japanese version of Three-Factor Eating Questionnaire Revised 21-item and stress response in food intake (large decrease vs. no change) were positively associated with the prevalence of fatigue assessed by the Japanese version of the Chalder Fatigue Scale. The finding suggests that emotional eating and decrease in amount of food intake under mental stress were associated with fatigue in healthy young adults. Our findings may help to clarify the mechanisms underlying fatigue-eating coupling as well as the etiology of diseases related to abnormal eating behavior.

Glucocorticoid and mineralocorticoid receptor polymorphisms and recurrence of major depressive disorder

OBJECTIVE

Previous research found that variants of the glucocorticoid receptor (GR) (9β, ER22/23EK, BclI, TthIIIl, NR3C1-1 and N363S) and mineralocorticoid receptor (MR) gene polymorphism (-2 C/G and I180V) are associated with both glucocorticoid (GC) sensitivity and major depressive disorder (MDD). There are no data which investigated prospectively whether these variants are associated with recurrence of MDD.

METHODS

Data were derived from the Netherlands Study of Depression and Anxiety (NESDA) which used the Composite International Diagnostic Interview (CIDI) to determine MDD. Polymorphisms in the GR and MR gene were determined and haplotypes were characterized. We analyzed in retrospect whether recurrent MDD (n=951) in comparison with first onset MDD (n=919) was associated with polymorphisms in the GR and MR gene. Furthermore, we analyzed prospectively for 4 years the time to recurrence among 683 subjects with a remitted MDD diagnosis. Time to recurrence of MDD was assessed using the CIDI and a life chart interview. Additionally, we analyzed interactions of the investigated polymorphisms with childhood trauma and recent negative life events.

RESULTS

GR and MR gene polymorphisms and derived haplotypes were not associated with recurrence of depression in both retrospective and prospective analyses. In addition, no consistent interactions between GR and MR polymorphisms and childhood trauma or life events were found.

CONCLUSION

This study did not find consistent associations between GR and MR gene polymorphisms, interactions between GR and MR haplotypes and stressful conditions and recurrence of MDD.

An excitatory synapse hypothesis of depression

Depression is a common cause of mortality and morbidity, but the biological bases of the deficits in emotional and cognitive processing remain incompletely understood. Current antidepressant therapies are effective in only some patients and act slowly. Here, we propose an excitatory synapse hypothesis of depression in which chronic stress and genetic susceptibility cause changes in the strength of subsets of glutamatergic synapses at multiple locations, including the prefrontal cortex (PFC), hippocampus, and nucleus accumbens (NAc), leading to a dysfunction of corticomesolimbic reward circuitry that underlies many of the symptoms of depression. This hypothesis accounts for current depression treatments and suggests an updated framework for the development of better therapeutic compounds.

Salivary cortisol results obtainable within minutes of sample collection correspond with traditional immunoassays

PURPOSE

Cortisol is frequently assayed as a stress-responsive biomarker which changes over the course of minutes to meet the demands of a person's social context. Salivary cortisol is often used as a noninvasive sampling method that possesses important health implications. A critical barrier to psychobiological research that involves salivary cortisol is a time delay of days to months before cortisol results are obtained via immunoassay, long after the person is no longer proximate to the social context in which they provided the sample. The present study was designed to address this critical barrier through creation of a lateral flow test (LFT) cortisol device capable of measuring salivary cortisol within minutes of sample collection. The LFT is frequently used within commercial point-of-care settings to obtain rapid answers to the presence/absence of a biomarker. The present study extends the LFT into the research domain by presenting performance characteristics of a quantitative LFT that measures salivary cortisol within 20 minutes of sample collection.

METHODS

Saliva samples from 29 adults (15 men) were obtained in the morning and afternoon by using Passive Drool and then the Super·SAL Extra Collection Device (hereafter Super·SAL) and later assayed with LFT and a commercially available enzyme immunoassay.

FINDINGS

Results indicate the LFT correlated well with these collection methods (R = 0.872 with Super · SAL, R = 0.739 with Passive Drool, P < 0.0001) and at comparable levels to correspondence of Super · SAL with Passive Drool (R = 0.798, P < 0.0001) which were measured with the same assay.

IMPLICATIONS

These results open an exciting new possibility to integrate this technologic advance into stress research, including knowing and potentially changing the person's social context in a time-sensitive manner. Methodological improvements such as this have the possibility of refining conceptual models of stress reactivity and regulation.