Glucocorticoid sensitivity of cognitive and inflammatory processes in depression and posttraumatic stress disorder

Antidepressant-like effects and cognitive enhancement of the total phenols extract of Hemerocallis citrina Baroni in chronic unpredictable mild stress rats and its related mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Depression induce distressed emotional state and cognitive deficits simultaneously, which both should be improved in the treatment. Hemerocallis citrina Baroni (HC) is a traditional herbal medicine in Eastern-Asia areas and the total phenols extract of HC (HCPE) contains the main active ingredients. It has been reported that HC has the emotional improvement effect. But the cognitive effect of HC was seldom researched.

AIM OF THE STUDY

We designed to evaluate the antidepressant and cognitive improvement effect of HCPE using a chronic unpredictable mild stress (CUMS) model, and the potential mechanisms were explored by investigating the corticosterone (CORT), monoamine neurotansmitters, brain-derived neurotropic factor (BDNF) and oxidative stress.

MATERIALS AND METHODS

The depression rats were induced by CUMS procedures and treated with HCPE (10, 20, 40mg/kg/day, by gastric gavage). The antidepressant effect was evaluated by sucrose preference test, open field test and body weight, while the cognitive improvement was investigated using morris water maze test. Besides, the levels of monoamine neurotransmitters in the hippocampus and frontal cortex were measured by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The serum CORT and BDNF in hippocampus were test using enzyme-linked immunosorbent assay (ELISA) kits. The oxidative stress indicators in frontal cortex were also analyzed.

RESULTS

HCPE (40mg/kg) improved the emotion and cognition related behaviors in depression effectively. Moreover, HCPE increased the neurotransmitters concentration (5-HT, DA and NE) in the hippocampus and frontal cortex compared with CUMS rats. Meanwhile, the CUMS induced changes of serum corticosterone level and the hippocampus BDNF level were reversed. Besides, HCPE reduced malondialdehyde (MDA) in the frontal cortex of model rats.

CONCLUSION

It suggested that HCPE could improve the depression-like emotional status and associated cognitive deficits in CUMS rats, which might be mediated by regulation of neurotransmitters and BDNF levels in brain, alleviation of corticosterone level as well as the alleviation of oxidative stress.

Glucocorticoid Induces Incoordination between Glutamatergic and GABAergic Neurons in the Amygdala

BACKGROUND

Stressful life leads to mood disorders. Chronic mild stress is presumably major etiology for depression, and acute severe stress leads to anxiety. These stressful situations may impair hypothalamus-pituitary-adrenal axis and in turn induce synapse dysfunction. However, it remains elusive how the stress hormones mess up subcellular compartments and interactions between excitatory and inhibitory neurons, which we have investigated in mouse amygdala, a structure related to emotional states.

METHODS AND RESULTS

Dexamethasone was chronically given by intraperitoneal injection once a day for one week or was acutely washed into the brain slices. The neuronal spikes and synaptic transmission were recorded by whole-cell patching in amygdala neurons of brain slices. The chronic or acute administration of dexamethasone downregulates glutamate release as well as upregulates GABA release and GABAergic neuron spiking. The chronic administration of dexamethasone also enhances the responsiveness of GABA receptors.

CONCLUSION

The upregulation of GABAergic neurons and the downregulation of glutamatergic neurons by glucocorticoid impair their balance in the amygdala, which leads to emotional disorders during stress.

Depression and resilience mediate the relationship between traumatic life events and ill physical health: results from a population study

We set out to investigate the mediating roles of depression, resilience, smoking, and alcohol use, in the relationship between potentially traumatic life events and objective and subjective, physical and mental health in a single study. A face-to-face, population-based survey was conducted in Hong Kong (N = 1147). Information on health conditions and traumatic life events was obtained, and participants completed measures of subjective physical and mental health, depression, and resilience. Smoking and drinking were not significant mediators of the relationship between life events and both objective and subjective health. Depressive symptomatology was found to mediate the relationship between life threatening illness and subjective physical health, the relationship between abuse (physical and sexual) and subjective mental health, and the relationship between the death of a parent/partner and subjective mental health. Resilience was found to mediate the relationships between multiple traumatic life events and subjective physical and mental health. Our results indicate that psychological factors rather than biological are important mediators of the relationship between life events exposure and health. Our findings provide evidence that depressive symptomatology has a mediating role only in the case of specific potentially traumatic life events and that resilience is only a critical factor in the face of exposure to multiple traumatic events, rather than single events. Our results also indicate that behavioural factors, such as smoking and drinking, are not significant mediators of the relationship between life events and health.

Role of neuroinflammation and sex hormones in war-related PTSD

The susceptibility to develop posttraumatic stress disorder (PTSD) is greatly influenced by both innate and environmental risk factors. One of these factors is gender, with women showing higher incidence of trauma-related mental health disorders than their male counterparts. The evidence so far links these differences in susceptibility or resilience to trauma to the neuroprotective actions of sex hormones in reducing neuroinflammation after severe stress exposure. In this review, we discuss the impact of war-related trauma on the incidence of PTSD in civilian and military populations as well as differences associated to gender in the incidence and recovery from PTSD. In addition, the mutually influencing role of inflammation, genetic, and sex hormones in modulating the consequences derived from exposure to traumatic events are discussed in light of current evidence.

Impaired GABA synthesis, uptake and release are associated with depression-like behaviors induced by chronic mild stress

Major depression is a prevalent emotion disorder. Chronic stressful life in genetically susceptible individuals is presumably a major etiology that leads to neuron and synapse atrophy in the limbic system. Molecular mechanisms underlying the pathological changes remain elusive. Mice were treated by chronic unpredictable mild stress (CUMS) until they demonstrated depression-like behavior. GABA release in the medial prefrontal cortex was evaluated by cell electrophysiology and imaging. Molecular profiles related to GABA synthesis and uptake were investigated by the high-throughput sequencings of microRNAs and mRNAs as well as western blot analysis in this cortical area. In CUMS-induced depression mice, there appear the decreases in the innervation and function of GABAergic axons and in the levels of mRNAs and proteins of glutamate decarboxylase-67, vesicular GABA transporter and GABA transporter-3. miRNA-15b-5p, miRNA-144-3p, miRNA-582-5p and miRNA-879-5p that directly downregulate such mRNAs increase in this cortex. Our results suggest that chronic mild stress impairs GABA release and uptake by upregulating miRNAs and downregulating mRNAs and proteins, which may constitute the subcellular and molecular mechanisms for the lowered GABA tone in major depression.

Aging and the HPA axis: Stress and resilience in older adults

Hypothalamic-pituitary-adrenal (HPA) axis function may change over the course of aging, and altered diurnal or stress-induced secretion of the hormone cortisol could predispose older adults to negative health outcomes. We propose that psychological resilience may interact with diurnal cortisol to affect health outcomes later in life. Emotion regulation and social support are two constructs that contribute to resilience and exhibit age-specific patterns in older adults. Determining how the use of resilience resources interacts with age-related diurnal cortisol will improve our understanding of the pathways between stress, resilience, and well-being. In this review, we assess published studies evaluating diurnal cortisol in older adults to better understand differences in their HPA axis functioning. Evidence thus far suggests that diurnal cortisol may increase with age, although cross-sectional studies limit the conclusions that can be drawn. We also review extant evidence connecting age-specific signatures of emotion regulation and social support with diurnal cortisol. Conclusions are used to propose a preliminary model demonstrating how resilience resources may modulate the effects of cortisol on health in aging.

Corticosterone regulates fear memory via Rac1 activity in the hippocampus

Stressful events can generate enduring memories, which may induce certain psychiatric disorders such as post-traumatic stress disorder (PTSD). However, the underlying molecular mechanisms in these processes remain unclear. In this study, we examined whether the active form of the small G protein Rac1, Rac1-GTP, is involved in fear memory. Firstly, we detected the time course changes of Rac1-GTP after foot shocks (a strong stressor) and exogenous corticosterone (CORT) treatment. The data showed that stress and CORT induced the downregulation of Rac1-GTP in the hippocampus. Changes in the serum CORT level were negatively correlated with the level of Rac1-GTP. Additionally, a glucocorticoid receptor antagonist, RU38486, not only recovered the expression of Rac1-GTP but also impaired fear memory. Furthermore, systemic administration of NSC23766, an inhibitor of Rac1-GTP, improved fear memory at 1.5 and 24h. Therefore, Rac1 activity plays a critical role in stress-related cognition and may be a potential target in stress-related disorders.

Neuroprotective, Neurotrophic and Anti-oxidative Role of Bacopa monnieri on CUS Induced Model of Depression in Rat

Major depression is a life threatening neuropsychiatric disorder that produces mental illness and major cause of morbidity. The present study was conducted to evaluate the neuroprotective, neurotrophic and antioxidant potential of Bacopa monnieri extract (BME) on chronic unpredictable stress (CUS) induced behavioral depression in rats. Behavioral tests were carried out for investigation of antidepressant like effects of BME, and potential mechanism was assessed by determining neurotrophin level and hippocampal neurogenesis. Depressive-like behavior was assessed by shuttle-box escape test, forced swim test and tail suspension test. Effect of BME on hypothalamic-pituitary-adrenal (HPA) axis was evaluated by measuring the plasma level of adrenocorticotropic hormone (ACTH) and corticosterone. The expression of brain derived neurotrophic factor (BDNF), neuronal marker doublecortin (DCX) in the hippocampus were measured and hippocampal neurogenesis was investigated by 5-bromo-2-deoxyuridine/neuronal nuclei (BrdU/NeuN). In addition, effects of BME on oxidative stress markers were also measured in the hippocampus of CUS exposed rats. The results indicated that BME significantly able to attenuate the depressive-like behaviors, normalized the levels of ACTH, corticosterone, and up-regulate the expression of BDNF, DCX and BrdU/NeuN in CUS induced rats compared to BME treated rats. It is also found that BME significantly increased the activity of antioxidant enzymes on CUS induced rats. These findings revealed that BME exerted neuroprotective effects possibly by promoting hippocampal neurogenesis with elevation of BDNF level and antioxidant defense against oxidative stress.

Physical Health Consequences of Interpersonal Trauma: A Systematic Review of the Role of Psychological Variables

Interpersonal forms of trauma are among the most commonly reported traumas. These types of traumas are more damaging to well-being than noninterpersonal forms. They have also been strongly associated with somatic symptoms and more general physical health problems. Nevertheless, the results of trauma studies are mixed and suggest that pathways may vary according to the stressors, mediators, and health outcomes investigated. This article presents a systematic qualitative review of published studies that have investigated interpersonal trauma, its association with physical health, and the potential role of intervening psychological variables. A systematic search was made of four psychology and health electronic databases. Of the 863 studies reviewed, 50 were preselected, 11 of which met the inclusion and methodological quality criteria. All but one study had a cross-sectional design. The findings showed that childhood trauma exposure was the most common category of interpersonal trauma addressed in the reviewed studies and that the physical health variables investigated were diverse. The psychological variables most frequently investigated in the studies were posttraumatic stress disorder, depression, dissociation, and substance abuse. Overall, the results suggest that interpersonal trauma exposure is associated with poorer physical health; however, the role of intervening psychological variables remains unclear. The limitations of the reviewed literature are discussed, and methodological recommendations are made for future research.

Molecular Mechanism for Stress-Induced Depression Assessed by Sequencing miRNA and mRNA in Medial Prefrontal Cortex

Background

Major depression is a prevalent mood disorder. Chronic stress is presumably main etiology that leads to the neuron and synapse atrophies in the limbic system. However, the intermediate molecules from stresses to neuronal atrophy remain elusive, which we have studied in the medial prefrontal cortices from depression mice.

Methods and Results

The mice were treated by the chronic unpredictable mild stress (CUMS) until they expressed depression-like behaviors confirmed by the tests of sucrose preference, forced swimming and Y-maze. High-throughput sequencings of microRNA and mRNA in the medial prefrontal cortices were performed in CUMS-induced depression mice versus control mice to demonstrate the molecular profiles of major depression. In the medial prefrontal cortices of depression-like mice, the levels of mRNAs that translated the proteins for the GABAergic synapses, dopaminergic synapses, myelination, synaptic vesicle cycle and neuronal growth were downregulated. miRNAs of regulating these mRNAs are upregulated.

Conclusion

The deteriorations of GABAergic and dopaminergic synapses as well as axonal growth are associated with CUMS-induced depression.

Protective effect of liquiritigenin on depressive-like behavior in mice after lipopolysaccharide administration

Liquiritigenin (Liq), the main active ingredient of traditional Chinese medicine licorice, possesses anti-inflammatory and neuroprotective properties. The current investigation was designed to explore whether liquiritigenin could relieve lipopolysaccharide (LPS)-induced depression-like behavior in mice and the underlying mechanism. Liquiritigenin (7.5mg/kg, 15mg/kg) and fluoxetine (20mg/kg) were pretreated intragastrically once daily for 7 consecutive days. LPS (0.5mg/kg) was injected subcutaneously to establish the depression model 30min after pretreatment on day 7. Interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels in serum and hippocampus were detected by enzyme-linked immunosorbent assay (ELISA). Behavioral assessment was conduct 24h post LPS injection. The expressions of p65NF-κB, IκBα, brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase B (TrkB) in hippocampus were determined by western blot. The obtained results showed that liquiritigenin effectively reduced the levels of pro-inflammatory cytokines and the expressions of p-p65NF-κB and p-IκBα. Furthermore, liquiritigenin preconditioning could down-regulate the immobility time in tail suspension test (TST), forced swimming test (FST) and up-regulate BDNF and TrkB contents in hippocampus. Thus, it is assumed that the antidepressant activity of liquiritigenin might be attributed to its anti-inflammatory property and BDNF/TrkB signaling pathway.

Incoordination among Subcellular Compartments Is Associated with Depression-Like Behavior Induced by Chronic Mild Stress

BACKGROUND

Major depressive disorder is characterized as persistent low mood. A chronically stressful life in genetically susceptible individuals is presumably the major etiology that leads to dysfunctions of monoamine and hypothalamus-pituitary-adrenal axis. These pathogenic factors cause neuron atrophy in the limbic system for major depressive disorder. Cell-specific pathophysiology is unclear, so we investigated prelimbic cortical GABAergic neurons and their interaction with glutamatergic neurons in depression-like mice.

METHODS

Mice were treated with chronic unpredictable mild stress for 3 weeks until they expressed depression-like behaviors confirmed by sucrose preference, Y-maze, and forced swimming tests. The structures and functions of GABAergic and glutamatergic units in prelimbic cortices were studied by cell imaging and electrophysiology in chronic unpredictable mild stress-induced depression mice vs controls.

RESULTS

In depression-like mice, prelimbic cortical GABAergic neurons show incoordination among the subcellular compartments, such as decreased excitability and synaptic outputs as well as increased reception from excitatory inputs. GABAergic synapses on glutamatergic cells demonstrate decreased presynaptic innervation and increased postsynaptic responsiveness.

CONCLUSIONS

Chronic unpredictable mild stress-induced incoordination in prelimbic cortical GABAergic and glutamatergic neurons dysregulates their target neurons, which may be the pathological basis for depressive mood. The rebalance of compatibility among subcellular compartments would be an ideal strategy to treat neural disorders.

Effects of social support on glucocorticoid sensitivity of lymphocytes in socially deprived piglets

There is growing evidence that social support given by a conspecific attenuates stress responses of a socially deprived animal. We hypothesized that the presence of a familiar social partner modulates the effectiveness of social buffering as assessed by an altered glucocorticoid sensitivity of immune cells. The current study investigated the effects of a 4-h social deprivation procedure on stress hormone responses and immune cell functions in 7-, 21- and 35-day-old piglets (52 males and 56 females). Within each of the three age categories, nine piglets were deprived of their mother and littermates either alone or with a familiar or unfamiliar age-matched piglet. Compared to non-deprived controls, piglets that were alone displayed significant increases in plasma adrenocorticotropic hormone and cortisol concentrations, and all socially deprived piglets showed a greater in vitro proliferative response of peripheral blood mononuclear cells (PBMCs) to lipopolysaccharide (LPS)-stimulation than controls. Concanavalin A (ConA)-induced in vitro proliferation was not affected by social treatment. Additionally, both the ConA- and LPS-stimulated PBMCs from piglets that experienced any of the deprivation treatments were more resistant to the inhibitory effects of cortisol than PBMCs from the controls in each of the three age categories. Irrespective of the mitogen used, the presence of an age-matched conspecific during deprivation attenuated the dose-dependent cortisol resistance. Here, familiarity between the piglets clearly improved the effectiveness of social support in an age-dependent manner. Collectively, our findings emphasize the benefits of social partners regarding stress coping abilities, with positive implications for animal welfare and health.

Glucocorticoid mediated regulation of inflammation in human monocytes is associated with depressive mood and obesity

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is observed in various conditions, including depression and obesity, which are also often related. Glucocorticoid (GC) resistance and desensitization of peripheral GC receptors (GRs) are often the case in HPA dysregulation seen in depression, and GC plays a critical role in regulation of inflammation. Given the growing evidence that inflammation is a central feature of some depression cases and obesity, we aimed to investigate the immune-regulatory role of GC-GR in relation to depressive mood and obesity in 35 healthy men and women. Depressive mood and level of obesity were assessed, using Beck Depression Inventory (BDI-Ia) and body mass index (BMI), respectively. We measured plasma cortisol levels via enzyme-linked immunosorbent assay and lipopolysaccharide-stimulated intracellular tumor necrosis factor (TNF) production by monocytes, using flow cytometry. Cortisol sensitivity was determined by the difference in monocytic TNF production between the conditions of 1 and 0 μM cortisol incubation ("cortisol-mediated inflammation regulation, CoMIR"). GR vs. mineralocorticoid receptor (MR) antagonism for CoMIR was examined by using mifepristone and spironolactone. A series of multiple regression analyses were performed to investigate independent contribution of depressive mood vs. obesity after controlling for age, gender, systolic blood pressure (SBP), and plasma cortisol in predicting CoMIR. CoMIR was explained by somatic subcomponents of depressive mood (BDI-S: β=-0.499, p=0.001), or BMI (β=-0.466, p<0.01) in separate models. The effects of BMI disappeared when BDI-S was controlled for in the model, while BDI-S remained a significant independent predictor for CoMIR (β=-0.369, p<0.05). However, BMI remained the only independent predictor when BDI-T or BDI-C were controlled for in the model. Mediation analyses also revealed that the relationship between BMI and CoMIR was mediated by BDI-S. The exploratory findings of the relative GR vs. MR roles in CoMIR, using GR and MR blockers, indicated that CoMIR in our cellular model was predominantly mediated by GRs at the higher cortisol dose (1 μM). There was initial indication that greater obesity and somatic depressive symptoms were associated with smaller efficacy of the blockers, which warrants further investigation. Our findings, although in a preclinical sample, signify the shared pathophysiology of immune dysregulation in depression and obesity and warrant further mechanistic investigation.

Better cognitive control of emotional information is associated with reduced pro-inflammatory cytokine reactivity to emotional stress

Stress is strongly associated with several mental and physical health problems that involve inflammation, including asthma, cardiovascular disease, certain types of cancer, and depression. It has been hypothesized that better cognitive control of emotional information may lead to reduced inflammatory reactivity to stress and thus better health, but to date no studies have examined whether differences in cognitive control predict pro-inflammatory cytokine responses to stress. To address this issue, we conducted a laboratory-based experimental study in which we randomly assigned healthy young-adult females to either an acute emotional stress (emotionally evocative video) or no-stress (control video) condition. Salivary levels of the key pro-inflammatory cytokines IL-1β, IL-6, and IL-8 were measured before and after the experimental manipulation, and following the last cytokine sample, we assessed participants' cognitive control of emotional information using an emotional Stroop task. We also assessed participants' cortisol levels before and after the manipulation to verify that documented effects were specific to cytokines and not simply due to increased nonwater salivary output. As hypothesized, the emotional stressor triggered significant increases in IL-1β, IL-6, and IL-8. Moreover, even in fully adjusted models, better cognitive control following the emotional (but not control) video predicted less pronounced cytokine responses to that stressor. In contrast, no effects were observed for cortisol. These data thus indicate that better cognitive control specifically following an emotional stressor is uniquely associated with less pronounced pro-inflammatory cytokine reactivity to such stress. These findings may therefore help explain why superior cognitive control portends better health over the lifespan.

Diagnostic Biomarkers for Posttraumatic Stress Disorder: Promising Horizons from Translational Neuroscience Research

Posttraumatic stress disorder (PTSD) is a heterogeneous disorder that affects individuals exposed to trauma (e.g., combat, interpersonal violence, and natural disasters). Although its diagnostic features have been recently reclassified with the emergence of the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition, the disorder remains characterized by hyperarousal, intrusive reminders of the trauma, avoidance of trauma-related cues, and negative cognition and mood. This heterogeneity indicates the presence of multiple neurobiological mechanisms underlying the etiology and maintenance of PTSD. Translational research spanning the past few decades has revealed several potential avenues for the identification of diagnostic biomarkers for PTSD. These include, but are not limited to, monoaminergic transmitter systems, the hypothalamic-pituitary-adrenal axis, metabolic hormonal pathways, inflammatory mechanisms, psychophysiological reactivity, and neural circuits. The current review provides an update to the literature with regard to the most promising putative PTSD biomarkers, with specific emphasis on the interaction between neurobiological influences on disease risk and symptom progression. Such biomarkers will most likely be identified by multi-dimensional models derived from comprehensive descriptions of molecular, neurobiological, behavioral, and clinical phenotypes.

Steroid regulation of T cell function appears unaltered in borderline personality disorder

Borderline personality disorder (BPD) is characterized by instability of interpersonal relationships and affection, impulsivity, and cognitive disruptions. Increasing evidence suggests hypothalamic-pituitary-adrenal (HPA) axis alterations in BPD. Changed glucocorticoid sensitivity of peripheral blood mononuclear cells is known in mood and posttraumatic stress disorders, representing frequent comorbidities in BPD. However, to the authors' knowledge, in BPD glucocorticoid sensitivity at the receptor level remains unexplored. Sixteen age-matched female BPD patients were compared to sixteen female healthy controls. In vitro steroid sensitivity of T cell proliferation was tested using aldosterone, dexamethasone, and hydrocortisone. Steroid sensitivity of BPD patients and healthy controls appeared comparable. Psychiatric comorbidities such as major depressive disorder or posttraumatic stress disorder and early life stress seemed to have had no influence on steroid sensitivity parameters. The data suggest unaltered GC sensitivity of T cell function in BPD.

Pre-deployment differences in glucocorticoid sensitivity of leukocytes in soldiers developing symptoms of PTSD, depression or fatigue persist after return from military deployment

Deployed soldiers are at risk of developing stress-related conditions, including posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and severe fatigue. We previously observed condition- and cell-specific differences in sensitivity of immune cells for regulation by glucocorticoids (GCs) pre-deployment between male soldiers with and without subsequent development of high levels of these stress-related symptoms. Here we investigated whether these pre-deployment dysregulations in GC-sensitivity of immune cells persisted after return from military deployment. In a prospective, longitudinal study including 721 male and female soldiers, the in vitro GC-sensitivity of monocytes and T-cells was assessed prior to deployment and one and six months post-deployment. Differences in the longitudinal course of sensitivity for regulation by dexamethasone (DEX) of LPS-stimulated TNF-α production and PHA-stimulated T-cell proliferation between soldiers with and without subsequent symptom development were investigated using linear mixed models. Within the whole group, DEX-sensitivity of monocytes was significantly decreased at six months post-deployment compared to the assessments pre-deployment and one month post-deployment. The DEX-sensitivity of T-cells did not significantly change over time. Participants developing high levels of PTSD symptoms showed high DEX-sensitivity of T-cells, while participants developing high levels of depressive symptoms showed low DEX-sensitivity of T-cells before deployment that persisted at the two time points after return. In addition, participants developing severe fatigue had low DEX-sensitivity of monocytes at all assessments. Our finding that the previously observed pre-deployment group differences in peripheral GC-sensitivity persisted until at least six months after return indicates that in vitro GC-sensitivity of T-cells and monocytes may represent a persistent biological vulnerability factor for development of stress-related conditions PTSD, depression and fatigue.

Effects of cortisol on cognition in major depressive disorder, posttraumatic stress disorder and borderline personality disorder - 2014 Curt Richter Award Winner

Stress hormones influence a wide range of cognitive functions, including memory performance and executive function. It is well established that glucocorticoids enhance memory consolidation but impair memory retrieval. While most of the effects have been attributed to glucocorticoid receptors (GR), the importance of mineralocorticoid receptors (MR) has been also emphasized. Dysfunctions in hypothalamic-pituitary-adrenal (HPA) axis have been reported for several mental disorders. While major depressive disorder (MDD) as well as borderline personality disorder (BPD) seem to be characterized by enhanced cortisol release in concert with a reduced feedback sensitivity of the HPA axis, in posttraumatic stress disorder (PTSD) a contrary picture has been reported. Despite the fact that altered GR function has been discussed for these disorders only very few studies have investigated the effects of glucocorticoids on cognitive performance in these patients so far. In a series of studies, we investigated the effects of glucocorticoids on cognition (i.e. declarative memory, working memory and response inhibition) in different mental disorders such as MDD, PTSD and BPD. While in patients with MDD cortisol administration failed to effect memory retrieval, patients with PTSD and BPD showed enhanced rather than impaired memory retrieval after cortisol administration. These results indicate an altered sensitivity to cortisol in these disorders. Results from one of our recent studies in the field of social cognition underline the importance of the MR. We found that emotional empathy was enhanced through stimulation of the MR via fludrocortisone in healthy participants and women with BPD. This review aims to integrate these findings and discuss potential mechanisms and implications.

Intra-individual psychological and physiological responses to acute laboratory stressors of different intensity

OBJECTIVES

The phenomenon of stress is understood as a multidimensional concept which can be captured by psychological and physiological measures. There are various laboratory stress protocols which enable stress to be investigated under controlled conditions. However, little is known about whether these protocols differ with regard to the induced psycho-physiological stress response pattern.

METHODS

In a within-subjects design, 20 healthy young men underwent four of the most common stress protocols (Stroop test [Stroop], cold pressor test [CPT], Trier Social Stress Test [TSST], and bicycle ergometer test [Ergometer]) and a no-stress control condition (rest) in a randomized order. For the multidimensional assessment of the stress response, perceived stress, endocrine and autonomic biomarkers (salivary cortisol, salivary alpha-amylase, and heart rate) were obtained during the experiments.

RESULTS

All stress protocols evoked increases in perceived stress levels, with the highest levels in the TSST, followed by Ergometer, Stroop, and CPT. The highest HPA axis response was found in the TSST, followed by Ergometer, CPT, and Stroop, whilst the highest autonomic response was found in the Ergometer, followed by TSST, Stroop, and CPT.

CONCLUSIONS

These findings suggest that different stress protocols differentially stimulate various aspects of the stress response. Physically demanding stress protocols such as the Ergometer test appear to be particularly suitable for evoking autonomic stress responses, whereas uncontrollable and social-evaluative threatening stressors (such as the TSST) are most likely to elicit HPA axis stress responses. The results of this study may help researchers in deciding which stress protocol to use, depending on the individual research question.

Enhanced emotional empathy after psychosocial stress in young healthy men

Empathy is a core prerequisite for human social behavior. Relatively, little is known about how empathy is influenced by social stress and its associated neuroendocrine alterations. The current study was designed to test the impact of acute stress on emotional and cognitive empathy. Healthy male participants were exposed to a psychosocial laboratory stressor (trier social stress test, (TSST)) or a well-matched control condition (Placebo-TSST). Afterwards they participated in an empathy test measuring emotional and cognitive empathy (multifaceted empathy test, (MET)). Stress exposure caused an increase in negative affect, a rise in salivary alpha amylase and a rise in cortisol. Participants exposed to stress reported more emotional empathy in response to pictures displaying both positive and negative emotional social scenes. Cognitive empathy (emotion recognition) in contrast did not differ between the stress and the control group. The current findings provide initial evidence for enhanced emotional empathy after acute psychosocial stress.

When time stands still: an integrative review on the role of chronodisruption in posttraumatic stress disorder

PURPOSE OF REVIEW

The human circadian system creates and maintains cellular and systemic rhythmicity essential to homeostasis. Loss of circadian rhythmicity fundamentally affects the neuroendocrine, immune and autonomic system, similar to chronic stress and, thus, may play a central role in the development of stress-related disorders. This article focuses on the role of circadian misalignment in the pathophysiology of posttraumatic stress disorder (PTSD).

RECENT FINDINGS

Sleep disruption is a core feature of PTSD supporting the important supraordinate pathophysiological role of circadian system in PTSD. Furthermore, direct and indirect human and animal PTSD research suggests circadian system linked neuroendocrine, immune, metabolic and autonomic dysregulation with blunted diurnal rhythms, specific sleep pattern pathologies and cognitive deficits, as well as endocannabinoid and neuropeptide Y system alterations and altered circadian gene expression, linking circadian misalignment to PTSD pathophysiology.

SUMMARY

PTSD development is associated with chronodisruption findings. Evaluation and treatment of sleep and circadian disruption should be the first steps in PTSD management. State-of-the-art methods of circadian rhythm assessment should be applied to bridge the gap between clinical significance and limited understanding of the relationship between traumatic stress, sleep and circadian system.

The Impact of Stress Hormones on Post-traumatic Stress Disorders Symptoms and Memory in Cardiac Surgery Patients

The relationship and interactions between stress hormones and post-traumatic stress disorder (PTSD) are well established from both animal and human research studies. This interaction is especially important in the post-operative phase of cardiac surgery where the development of PTSD symptoms will result in increased morbidity and mortality and prolong length of stay for critically ill cardiac surgery patients. Cardiopulmonary bypass itself will independently result in massive inflammation response and release of stress hormones in the perioperative period. Glucocorticoid may reduce this response and result in reduction of PTSD symptom clusters and therefore improve health outcome. In this review, we plan to conduct a systemic review and analysis of the literatures on this topic.

Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a 5-HT2A/C receptor agonist

The neuronal tetraspan proteins, M6A (Gpm6a) and M6B (Gpm6b), belong to the family of proteolipids that are widely expressed in the brain. We recently reported Gpm6a deficiency as a monogenetic cause of claustrophobia in mice. Its homolog proteolipid, Gpm6b, is ubiquitously expressed in neurons and oligodendrocytes. Gpm6b is involved in neuronal differentiation and myelination. It interacts with the N-terminal domain of the serotonin transporter (SERT) and decreases cell-surface expression of SERT. In the present study, we employed Gpm6b null mutant mice (Gpm6b(-/-)) to search for behavioral functions of Gpm6b. We studied male and female Gpm6b(-/-) mice and their wild-type (WT, Gpm6b(+/+)) littermates in an extensive behavioral test battery. Additionally, we investigated whether Gpm6b(-/-) mice exhibit changes in the behavioral response to a 5-HT2A/C receptor agonist. We found that Gpm6b(-/-) mice display completely normal sensory and motor functions, cognition, as well as social and emotionality-like (anxiety, depression) behaviors. On top of this inconspicuous behavioral profile, Gpm6b(-/-) mice of both genders exhibit a selective impairment in prepulse inhibition of the acoustic startle response. Furthermore, in contrast to WT mice that show the typical locomotion suppression and increase in grooming activity after intraperitoneal administration of DOI [(±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride], Gpm6b(-/-) mice demonstrate a blunted behavioral response to this 5-HT2A/C receptor agonist. To conclude, Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a serotonergic challenge.

Social support modulates splenocyte glucocorticoid sensitivity in piglets exposed to social deprivation stress

There is growing evidence that positive social interactions can attenuate the effects of stressful life experiences. However, little is known about the benefits of social partners on stress responses in farm animals. Therefore, in this study we examined the effects of social support on the endocrine and immune stress responses to a single 4h social deprivation in domestic piglets at 7, 21 or 35days of age. The piglets were socially deprived of their mother and littermates. They were left alone (DA) or in the presence of a familiar (DF) or unfamiliar (DU) age-matched piglet. Non-socially deprived piglets served as a control. DA piglets displayed elevated plasma cortisol levels, higher lipopolysaccharide (LPS)-stimulated proliferation of splenocytes and increased TNF-α and IL-6 production in splenocyte cultures than the control piglets. There were no significant buffering effects of social partners on stress-induced plasma cortisol levels and splenocyte proliferation in response to LPS. However, the presence of an age-matched conspecific diminished the IL-6 production by splenocytes in younger, socially deprived piglets, and it reduced the TNF-α release in the older piglets. Compared to the controls, LPS-stimulated splenocytes from DA piglets were more resistant to the inhibitory effects of cortisol, which was demonstrated by a higher proliferative response and increased production of pro-inflammatory cytokines. The dose-dependent cortisol resistance was attenuated by the presence of a familiar or an unfamiliar conspecific at each of the three age categories. Indeed, in the present study, the familiarity level of the social partners did not seem to play a role in the alleviation of social stress-induced inflammatory activity and splenocyte cortisol resistance. In addition, the buffering effect of social support provided by an age-matched conspecific was more pronounced in older piglets. Conclusively, these findings suggest that social support is an important factor for enhancing piglets' abilities to cope with stressful challenges, and it may be a key approach needed to improve the health and welfare of farm animals.

Stimulation of systemic low-grade inflammation by psychosocial stress

Psychosocial stress is an important precursor of disease and reduced quality of life in humans. The biological pathways between stress exposure and pathophysiological processes underlying disease have received substantial scientific attention, although the roles of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system remain insufficiently understood. Recent attention has focused on chronic systemic low-grade inflammation as a promising pathway because elevated inflammation often accompanies chronic psychosocial distress. These alterations of inflammatory activity play a key role in the pathophysiology of diseases that are adversely affected by chronic distress, such as cardiovascular disease. Transient increases in systemic inflammation are observed in response to acute psychosocial stress, with larger responses among individuals reporting adverse psychosocial states or conditions such as depression, lower self-esteem, or lower self-compassion. Recent evidence shows that lower subjective social status and perceived purpose in life are associated with sensitization of inflammatory stress responses to repeated stress exposure. The aims of this selective review article are to summarize current knowledge of the role of acute and chronic psychosocial stress on low-grade inflammation in humans and to discuss potential relationships between inflammatory responses to acute psychosocial stress and long-term development of disease.

Reduced peripheral expression of the glucocorticoid receptor α isoform in individuals with posttraumatic stress disorder: a cumulative effect of trauma burden

BACKGROUND

Posttraumatic stress disorder (PTSD) is a serious psychiatric condition that was found to be associated with altered functioning of the hypothalamic-pituitary-adrenal (HPA) axis and changes in glucocorticoid (GC) responsiveness. The physiological actions of GCs are primarily mediated through GC receptors (GR) of which isoforms with different biological activities exist. This study aimed to investigate whether trauma-experience and/or PTSD are associated with altered expression of GR splice variants.

METHODS

GRα and GRβ mRNA expression levels were determined by real-time quantitative PCR in whole blood samples of individuals with chronic and severe forms of PTSD (n = 42) as well as in ethnically matched reference subjects (non-PTSD, n = 35).

RESULTS

Individuals suffering from PTSD exhibited significantly lower expression of the predominant and functionally active GRα isoform compared to non-PTSD subjects. This effect remained significant when accounting for gender, smoking, psychotropic medication or comorbid depression. Moreover, the GRα expression level was significantly negatively correlated with the number of traumatic event types experienced, both in the whole sample and within the PTSD patient group. Expression of the less abundant and non-ligand binding GRβ isoform was comparable between patient and reference groups.

CONCLUSIONS

Reduced expression of the functionally active GRα isoform in peripheral blood cells of individuals with PTSD seems to be a cumulative effect of trauma burden rather than a specific feature of PTSD since non-PTSD subjects with high trauma load showed an intermediate phenotype between PTSD patients and individuals with no or few traumatic experiences.

Neuroimmunoendocrine interactions in post-traumatic stress disorder: focus on long-term implications of childhood maltreatment

Childhood maltreatment has been linked to enhanced vulnerability to psychiatric pathologies in adult life, including post-traumatic stress disorder (PTSD). Previous works have reported cogent neuroendocrine and immune changes related to adult traumatic events (war survivors, refugees, etc.), but little information is known regarding the impact of early-life stress (ELS) in adult physiology. Here, we review the neuroendocrine and immunological changes commonly observed in PTSD, focusing on the long-term implications of ELS. Childhood maltreatment may lead to altered glucocorticoid (GC) secretion, resulting in hypo- or hypercortisolemia, and reciprocal changes in peripheral leukocyte sensitivity to GC. It is believed that these neuroendocrine changes are correlated with the immune imbalance phenomenon (low-grade inflammation), characterized by increased plasma levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and C-reactive protein. Changes in peripheral lymphocyte subsets are also documented, such as a reduction in regulatory T cells and an expansion of activated T cells. The excess of circulating cytokines may thus interfere with key brain neurotransmitter pathways involved in depression and enhanced risk to cardiovascular, respiratory, gastrointestinal, inflammatory and autoimmune diseases. Recent gene-environment and epigenetic findings have indicated potential molecular mechanisms linking ELS, neuroendocrine and immunity in PTSD.

Peripheral blood mononuclear cell-based metabolomic profiling of a chronic unpredictable mild stress rat model of depression

Major depressive disorder (MDD) is a debilitating mood disorder with various etiopathological hypotheses.

Preparation of a sustained release drug delivery system for dexamethasone by a thermosensitive, in situ forming hydrogel for use in differentiation of dental pulp

In situ forming delivery systems composed of block copolymers are attracting substantial attention due to their ease of use, biocompatibility, and biodegradability. In this study, the thermoresponsive triblock copolymer PLGA-PEG-PLGA was studied as a dexamethasone delivery system. Dexamethasone, a synthetic glucocorticoid, is used clinically to improve inflammation, pain, and the hyperemesis of chemotherapy, and it is applied experimentally as a differentiation factor in tissue engineering. PLGA-PEG-PLGA was synthesised under microwave irradiation for 5 min. The obtained copolymer was characterised to determine its structure and phase transition temperature. An in vitro release study was conducted for various copolymer structures and drug concentrations. The yield of the reaction and HNMR analysis confirmed the appropriateness of the microwave-assisted method for PLGA-PEG-PLGA synthesis. Phase transition temperature was affected by the drug molecule as well as by the copolymer concentration and structure. An in vitro release study demonstrated that release occurs mainly by diffusion and does not depend on the copolymer structure or dexamethasone concentration.

Effects of perillaldehyde on alternations in serum cytokines and depressive-like behavior in mice after lipopolysaccharide administration

Perillaldehyde (PAH), a major component of essential oil of Perilla Frutescens, has antidepressant-like effects and anti-inflammatory effects. The present study was designed to determine whether PAH is effective in treating lipopolysaccharide (LPS)-induced depression-like behavior in mice and to explore the possible mechanism between its antidepressant-like effect and anti-inflammatory activity. PAH (60 and 120 mg/kg) and fluoxetine (20mg/kg) were administered intragastrically once daily for 7 consecutive days. In the 7th day, LPS (0.5mg/kg) was injected intraperitoneally 30 min after drug administration. Blood samples were collected 90 min after LPS injection to evaluate serum interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels by enzyme-linked immunosorbent assay (ELISA). Behavioral tests were measured 24h after LPS injection. After the behavioral tests the prefrontal cortex was rapidly dissected from the brain of the sacrificed mice, then the 5-hydroxytryptamine (5-HT) and norepinephrine (NE) levels in prefrontal cortex were determined by HPLC-MS, and IL-6 and TNF-α mRNA expression was measured using quantitative real-time PCR. Our results showed that a single administration of LPS significantly increased the levels of TNF-α and IL-6 in both the serum and the prefrontal cortex and decreased 5-HT and NE levels in the prefrontal cortex in mice. Pretreatment with fluoxetine (20mg/kg) or PAH (60 and 120 mg/kg) could effectively reverse the alterations in the concentrations of 5-HT and NE, and attenuate LPS-induced increases in TNF-α and IL-6 levels. Besides, LPS administration increased the immobility time in tail suspension test (TST) and forced swimming test (FST) without affecting spontaneous locomotor activity. Fluoxetine (20mg/kg) or PAH (60 and 120 mg/kg) significantly shortened LPS-induced increases of immobility time in both TST and FST. In conclusion, PAH exhibited significant antidepressant-like effects in mice with LPS-induced depression. The antidepressant activity of PAH might be related to the alteration of monoaminergic responses and the anti-inflammatory effects.

Effects of acute cortisol administration on response inhibition in patients with major depression and healthy controls

Glucocorticoids (GCs) have repeatedly been shown to impair hippocampus-mediated, declarative memory retrieval and prefrontal cortex-based working memory in healthy subjects. However, recent experimental studies indicated that patients with major depressive disorder (MDD) lack these impairing effects. These missing effects have been suggested to result from dysfunctional brain GC receptors. The purpose of the present study was to investigate whether response inhibition, an executive function relying on the integrity of the prefrontal cortex, would be impaired after cortisol administration in patients with MDD. In a placebo-controlled, double blind crossover study, 50 inpatients with MDD and 54 healthy control participants conducted an emotional go/no-go task consisting of human face stimuli (fearful, happy, and neutral) after receiving a dose of 10 mg hydrocortisone and after placebo. GC administration had an enhancing effect on inhibitory performance in healthy control participants, indicated by faster responses, while no GC effect was revealed for the patients group. Moreover, patients showed an overall worse performance than healthy participants. In conclusion, this study further supports the hypothesis of impaired central glucocorticoid receptor function in MDD patients. Regarding the importance of inhibitory functioning for daily living, further studies are needed to examine the impact of glucocorticoids on response inhibition.

Cortisol effects on autobiographic memory retrieval in PTSD: an analysis of word valence and time until retrieval

In healthy participants, cortisol administration has been found to impair autobiographic memory retrieval. We recently reported that administration of 10 mg of hydrocortisone had enhancing effects on autobiographical memory retrieval, i.e. more specific memory retrieval, in patients with posttraumatic stress disorder (PTSD), while in healthy controls the impairing effects were replicated. We here report a re-analysis of these data with respect to cue-word valence and retrieval time. In a placebo-controlled cross-over study, 43 patients with PTSD and 43 age- and sex-matched healthy controls received either placebo or hydrocortisone orally before the autobiographical memory test was performed. We found that the effects of cortisol on memory retrieval depended on cue-word valence and group (significant interaction effects of drug by group and drug by valence by group). The enhancing effect of cortisol on memory retrieval in PTSD seemed to be relatively independent of cue-word valence, while in the control group the impairing effects of cortisol were only seen in response to neutral cue-words. The second result of the study was that in patients as well as in controls, cortisol administration led to faster memory retrieval compared to placebo. This was seen in response to positive and (to lesser extend) to neutral cue-words, but not in response to negative cue-words. Our findings illustrate that the opposing effects of cortisol on autobiographical memory retrieval in PTSD patients and controls are further modulated by the emotionality of the cue-words.

Lymphocyte glucocorticoid receptor expression level and hormone-binding properties differ between war trauma-exposed men with and without PTSD

OBJECTIVE

Posttraumatic stress disorder (PTSD) has been shown to be associated with altered glucocorticoid receptor (GR) activity. We studied the expression and functional properties of the receptor in peripheral blood mononuclear cells (PBMCs) from non-traumatized healthy individuals (healthy controls; n=85), and war trauma-exposed individuals with current PTSD (n=113), with life-time PTSD (n=61) and without PTSD (trauma controls; n=88). The aim of the study was to distinguish the receptor alterations related to PTSD from those related to trauma itself or to resilience to PTSD.

METHODS

Functional status of the receptor was assessed by radioligand binding and lysozyme synthesis inhibition assays. The level of GR gene expression was measured by quantitative PCR and immunoblotting.

RESULTS

Current PTSD patients had the lowest, while trauma controls had the highest number of glucocorticoid binding sites (Bmax) in PBMCs. Hormone-binding potential (Bmax/KD ratio) of the receptor was diminished in the current PTSD group in comparison to all other study groups. Correlation between Bmax and KD that normally exists in healthy individuals was decreased in the current PTSD group. Contrasting Bmax data, GR protein level was lower in trauma controls than in participants with current or life-time PTSD.

CONCLUSIONS

Current PTSD is characterized by reduced lymphocyte GR hormone-binding potential and by disturbed compensation between Bmax and hormone-binding affinity. Resilience to PTSD is associated with enlarged fraction of the receptor molecules capable of hormone binding, within the total receptor molecule population in PBMCs.

Predicting PTSD: pre-existing vulnerabilities in glucocorticoid-signaling and implications for preventive interventions

Posttraumatic stress disorder (PTSD) is an anxiety disorder that may develop in response to a traumatic event. Approximately 10% of trauma-exposed individuals subsequently develop PTSD. It is hypothesized that the development of PTSD is associated with biological vulnerability factors, which are already present prior to the onset of symptoms. In this review we present an overview of currently identified vulnerability factors in the glucocorticoid (GC) signaling pathway for the development of PTSD. In addition, the implications of the identified vulnerability factors for potential preventive intervention strategies, including glucocorticoid receptor (GR) agonists and oxytocin, are discussed. Summarized, the findings of these studies indicate that individuals vulnerable for development of PTSD have dysregulations on various levels of the GC-signaling cascade: i.e. low levels of circulating levels of cortisol shortly after trauma, high GR number in peripheral blood mononuclear cells (PBMCs), high GILZ mRNA expression and low FKBP5 expression in PBMCs prior to trauma, and high sensitivity of T-cells for regulation by GCs prior to trauma. Furthermore, single nucleotide polymorphisms in the GR and FKBP5 genes have been found to be associated with increased risk for PTSD. Collectively, the identified vulnerability factors tentatively suggest that the development of PTSD may be preceded by a high sensitivity of various cells for regulation by GCs. The identification of these vulnerability factors may ultimately aid selective targeting of preventive interventions towards individuals at risk for PTSD. In addition, the identification of these vulnerability factors may eventually result in new preventive pharmacological strategies for PTSD.

Nobiletin Ameliorates the Deficits in Hippocampal BDNF, TrkB, and Synapsin I Induced by Chronic Unpredictable Mild Stress

Background. Our previous study has demonstrated that nobiletin could reverse the behavioral alterations in stressed mice. However, the relation of its antidepressant-like action with neurotrophic molecular expression remains unknown. This study aimed to explore the antidepressant-like mechanism of nobiletin related to the neurotrophic system in rats exposed to chronic unpredictable mild stress (CUMS). Methods. Depressive-like anhedonia (assessed by sucrose preference) and serum corticosterone secretion were evaluated in the CUMS, followed by brain-derived neurotrophic factor (BDNF), its tropomyosin-related kinase receptor B (TrkB), and the downstream target synapsin I expressions in the hippocampus. Results. Anhedonia, which occurred within week 2, was rapidly ameliorated by nobiletin. While fluoxetine needed additional 2 weeks to improve the anhedonia. In addition, nobiletin administration for 5 weeks significantly ameliorated CUMS-induced increase in serum corticosterone levels. Furthermore, we also found that CUMS-induced deficits of hippocampal BDNF, TrkB, and synapsin I were ameliorated by nobiletin. Conclusions. Taken together, these findings suggest that nobiletin produces rapidly acting antidepressant-like responses in the CUMS and imply that BDNF-TrkB pathway may play an important role in the antidepressant-like effect of nobiletin.

Associations between cognitive performance and cortisol reaction to the DEX/CRH test in patients recovered from depression

BACKGROUND

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis in major depression (MDD) is one of the most reliably reported neurobiological characteristics of affective disorders. Whether these alterations in HPA axis regulation are limited to the acute stage of MDD or whether they persist after recovery, remains ambiguous. A relationship between hypercortisolemia and cognitive dysfunction in acutely depressed patients has been repeatedly observed and it was also demonstrated in a number of studies that a discrete cognitive impairment often persists in the remitted state of depression. In the present study we were interested, whether these subtle impairments in cognitive functioning observed in patients recovered from depression compared to healthy control subjects are associated with HPA axis feedback sensitivity.

METHODS

In 20 recovered patients and 20 matched healthy controls we assessed HPA axis feedback sensitivity with the combined dexamethasone suppression/corticotropin-releasing-hormone (DEX/CRH) challenge test. Furthermore cognitive performance was investigated with respect to the following domains: verbal memory (Auditory Verbal Learning Test, VLMT), attention and executive control (Trail Making Test, TMT-A/B) as well as verbal fluency (Controlled Oral Word Association Test, COWAT).

RESULTS

Recovered patients showed a significantly poorer cognitive performance compared to healthy controls (all p<.05). With regard to HPA-axis activity, no overall difference was observed in the DEX/CRH test between recovered patients and controls. In recovered patients however, a significant association was observed between cortisol response and verbal memory (main effect VLMT trial 1-5: p=.046), attention (main effect TMT-A: p=.015) and executive functioning in terms of set shifting (interaction samples*TMT-B: p=.018). Poorer test performance was related to increased cortisol levels in response to challenge.

CONCLUSIONS

The present findings suggest that patients recovered from MDD are especially vulnerable toward detrimental effects of subtle HPA axis disturbances on cognitive performance.

Effects of cortisol on memory in women with borderline personality disorder: role of co-morbid post-traumatic stress disorder and major depression

BACKGROUND

Stress and cortisol administration are known to have impairing effects on memory retrieval in healthy humans. These effects are reported to be altered in patients with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) but they have not yet been investigated in borderline personality disorder (BPD).

METHOD

In a placebo-controlled cross-over study, 71 women with BPD and 40 healthy controls received either placebo or 10 mg of hydrocortisone orally before undertaking a declarative memory retrieval task (word list learning) and an autobiographical memory test (AMT). A working memory test was also applied.

RESULTS

Overall, opposing effects of cortisol on memory were observed when comparing patients with controls. In controls, cortisol had impairing effects on memory retrieval whereas in BPD patients cortisol had enhancing effects on memory retrieval of words, autobiographical memory and working memory. These effects were most pronounced for specificity of autobiographical memory retrieval. Patients with BPD alone and those with co-morbid PTSD showed this effect. We also found that co-morbid MDD influenced the cortisol effects: in this subgroup (BPD + MDD) the effects of cortisol on memory were absent.

CONCLUSIONS

The present results demonstrate beneficial effects of acute cortisol elevations on hippocampal-mediated memory processes in BPD. The absence of these effects in patients with co-morbid MDD suggests that these patients differ from other BPD patients in terms of their sensitivity to glucocorticoids (GCs).

Using optogenetics to translate the "inflammatory dialogue" between heart and brain in the context of stress

Inflammatory processes are an integral part of the stress response and are likely to result from a programmed adaptation that is vital to the organism's survival and well-being. The whole inflammatory response is mediated by largely overlapping circuits in the limbic forebrain, hypothalamus and brainstem, but is also under the control of the neuroendocrine and autonomic nervous systems. Genetically predisposed individuals who fail to tune the respective contributions of the two systems in accordance with stressor modality and intensity after adverse experiences can be at risk for stress-related psychiatric disorders and cardiovascular diseases. Altered glucocorticoid (GC) homeostasis due to GC resistance leads to the failure of neural and negative feedback regulation of the hypothalamic-pituitary-adrenal axis during chronic inflammation, and this might be the mechanism underlying the ensuing brain and heart diseases and the high prevalence of co-morbidity between the two systems. By the combined use of light and genetically-encoded light-sensitive proteins, optogenetics allows cell-type-specific, fast (millisecond-scale) control of precisely defined events in biological systems. This method is an important breakthrough to explore the causality between neural activity patterns and behavioral profiles relevant to anxiety, depression, autism and schizophrenia. Optogenetics also helps to understand the "inflammatory dialogue", the inflammatory processes in psychiatric disorders and cardiovascular diseases, shared by heart and brain in the context of stress.

Trauma exposure and health: the role of depressive and hyperarousal symptoms

Posttraumatic stress disorder (PTSD) and depressive symptoms have been theorized to mediate the relationship between trauma exposure and physical health symptoms. Although empirical evidence supports this premise, studies conducted to date have employed statistical mediation analyses that are now broadly criticized. Furthermore, the mediating roles of both PTSD and depressive symptoms have seldom been examined concurrently, and it remains unclear which PTSD symptom clusters uniquely mediate this relationship. The aim of the present study was to examine the mediating role of reexperiencing, avoidance/numbing, hyperarousal, and depressive symptoms in the relationship between trauma exposure and physical health symptoms. Participants were 516 Spanish female undergraduate students. Physical health symptoms were compared between those who reported trauma exposure (n = 266) and those who did not (n = 250). Data from trauma-exposed participants were analyzed using regression models with bootstrapping to test mediation. Results of the analyses showed that the trauma-exposed group reported significantly more physical health symptoms (r(2) = .035). Hyperarousal and depressive symptoms uniquely mediated the relationship between trauma exposure and physical health symptoms. Our findings clarify some of the mechanisms by which negative health consequences occur subsequent to trauma exposure.

Association between reduced expression of hippocampal glucocorticoid receptors and cognitive dysfunction in a rat model of traumatic brain injury due to lateral head acceleration

Expression of hippocampal glucocorticoid receptors (GRs) and spatial learning and memory were observed in rat model of diffuse traumatic brain injury (TBI) due to lateral head acceleration with an aim at investigating the relation between GRs expression and cognitive deficits. Immunohistochemical staining, Western blotting, and RT-PCR indicated that down-regulation of GRs expression occurred in the hippocampus among TBI-rats which demonstrated reduced performance of learning and memory in Morris water maze. As the GRs expression bounced up, the cognitive function approached to normal. It is concluded that reduced expression of hippocampal GRs was closely associated with learning and memory deficits in TBI-rats. Hippocampal GRs was involved in the biochemical mechanisms of cognitive deficits after TBI.

Exaggerated neurobiological sensitivity to threat as a mechanism linking anxiety with increased risk for diseases of aging

Anxiety disorders increase risk for the early development of several diseases of aging. Elevated inflammation, a common risk factor across diseases of aging, may play a key role in the relationship between anxiety and physical disease. However, the neurobiological mechanisms linking anxiety with elevated inflammation remain unclear. In this review, we present a neurobiological model of the mechanisms by which anxiety promotes inflammation. Specifically we propose that exaggerated neurobiological sensitivity to threat in anxious individuals may lead to sustained threat perception, which is accompanied by prolonged activation of threat-related neural circuitry and threat-responsive biological systems including the hypothalamic-pituitary-adrenal (HPA) axis, autonomic nervous system (ANS), and inflammatory response. Over time, this pattern of responding can promote chronic inflammation through structural and functional brain changes, altered sensitivity of immune cell receptors, dysregulation of the HPA axis and ANS, and accelerated cellular aging. Chronic inflammation, in turn, increases risk for diseases of aging. Exaggerated neurobiological sensitivity to threat may thus be a treatment target for reducing disease risk in anxious individuals.

Glucocorticoid sensitivity of leukocytes predicts PTSD, depressive and fatigue symptoms after military deployment: A prospective study

AIM

Posttraumatic stress disorder (PTSD), major depressive disorder (MDD), and severe fatigue may develop in response to severe stress and trauma. These conditions have all been shown to be associated with altered sensitivity of leukocytes for regulation by glucocorticoids (GCs). However, it remains unknown whether sensitivity of leukocytes for GCs is a pre-existing vulnerability factor, or whether GC-sensitivity of leukocytes alters as a consequence of stress and stress-related conditions. Our aim was to investigate whether sensitivity of T-cells and monocytes for regulation by GCs (i.e. dexamethasone: DEX) assessed before military deployment predicts high levels of PTSD, depressive, and/or fatigue symptoms 6 months after return from deployment.

METHODS

We included 526 male military personnel before deployment to Afghanistan. Logistic regression analysis was performed to predict fatigue, depressive, and PTSD symptoms 6 months after deployment based on sensitivity of LPS-induced TNF-α production and PHA-induced T-cell proliferation to DEX-inhibition before deployment.

RESULTS

Severe fatigue 6 months after deployment was independently associated with low DEX-sensitivity of monocyte TNF-α production before deployment. A high level of depressive symptoms after deployment was independently associated with a low DEX-sensitivity of T-cell proliferation. In contrast, a high level of PTSD symptoms after deployment was independently associated with a high DEX-sensitivity of T-cell proliferation before deployment, but only in individuals who reported PTSD symptoms without depressive symptoms. The predictive value of DEX-sensitivity was independent of childhood trauma and GR number, GR subtype and GR target gene mRNA expression in leukocytes.

CONCLUSIONS

We present here for the first time that the sensitivity of leukocytes for GCs prior to deployment is a predictive factor for the development of PTSD, depressive and fatigue symptomatology in response to deployment. Notably, PTSD, depressive and fatigue symptoms were differentially associated with GC-sensitivity of monocytes and T-cells and therefore may have different biological underpinnings.

Antidepressant-like behavioral, neurochemical and neuroendocrine effects of naringenin in the mouse repeated tail suspension test

Our previous study demonstrated that the citrus bioflavonoid naringenin ameliorated behavioral alterations via the central serotonergic and noradrenergic systems in the tail suspension test (TST) induced mice. To better understand its pharmacological activity, mice were submitted to three 6min-TSTs one week apart (Day 1: test, Day 7: retest 1, Day 14: retest 2) followed by hippocampal glucocorticoid receptor (GR), monoamine neurotransmitters and serum corticosterone measurement. The results suggested that repeated TST detected the gradual increase in the efficacy of naringenin over time, additionally 1-day (20 mg/kg), 7-day (10, 20 mg/kg) and 14-day (5, 10, 20 mg/kg) naringenin treatment markedly decreased the immobility time. Moreover, administration of naringenin for 14 days (20 mg/kg) increased hippocampal serotonin (5-HT), norepinephrine (NE) and GR levels, and reduced serum corticosterone levels in mice exposed to the repeated TST. Overall, the present study indicated that the re-exposure would facilitate the detection of the anti-immobility effects of antidepressant drugs in the mouse TST, and clearly demonstrated that the antidepressant-like effect of naringenin may be mediated by an interaction with neuroendocrine and neurochemical systems.

Cortisol has enhancing, rather than impairing effects on memory retrieval in PTSD

BACKGROUND

In the present study, we aimed to compare the effect of exogenous cortisol on memory retrieval in posttraumatic stress disorder (PTSD) with the effects in healthy controls. In healthy participants, administration of cortisol impairs declarative memory retrieval. Only a few studies have investigated these effects in PTSD yielding mixed results.

METHODS

In a placebo-controlled crossover study, 44 patients with PTSD and 65 healthy controls received either placebo or 10mg of hydrocortisone orally before memory testing. In addition to declarative memory retrieval (word list learning), we also tested autobiographical memory retrieval specificity.

RESULTS

In both tasks opposing effects of cortisol on memory were observed when comparing patients with controls. In controls, cortisol had impairing effects on memory retrieval, while in PTSD patients cortisol had enhancing effects on memory retrieval in both memory domains.

CONCLUSIONS

The present results suggest beneficial effects of acute cortisol elevations on hippocampal mediated memory processes in PTSD. Possible neurobiological mechanisms underlying these findings are discussed.

Altered salivary alpha-amylase awakening response in Bosnian War refugees with posttraumatic stress disorder

In posttraumatic stress disorder (PTSD), chronic activation of the sympathetic nervous system (SNS) has been suggested. No study so far has investigated diurnal secretion patterns of salivary alpha-amylase (sAA) in PTSD, a promising candidate for non-invasive assessment of SNS activity. We compared sAA diurnal profiles between a group of Bosnian War refugees with PTSD and a healthy control group, and further analyzed for associations with psychiatric symptoms and glucocorticoid (GC) sensitivity of inflammatory regulation. PTSD patients showed a sAA awakening response profile that was opposite to those seen in healthy controls, i.e. an increase instead of a sharp decrease. Patterns of sAA secretion were further positively associated with psychiatric symptoms of PTSD. Finally, higher sAA awakening responses were associated with higher GC sensitivity of inflammatory cytokine production. These findings are in line with altered SNS function in PTSD, and lend further support for employing assessment of diurnal sAA profiles as non-invasive biomarkers in stress-related disease.

Can variation in hypothalamic-pituitary-adrenal (HPA)-axis activity explain the relationship between depression and cognition in bipolar patients?

Background

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is thought to be associated with more mood symptoms and worse cognitive functioning. This study examined whether variation in HPA axis activity underlies the association between mood symptoms and cognitive functioning.

Methodology/Principal Findings

In 65 bipolar patients cognitive functioning was measured in domains of psychomotor speed, speed of information processing, attentional switching, verbal memory, visual memory, executive functioning and an overall mean score. Severity of depression was assessed by the Inventory of Depressive Symptomatology-self rating version. Saliva cortisol measurements were performed to calculate HPA axis indicators: cortisol awakening response, diurnal slope, the evening cortisol level and the cortisol suppression on the dexamethasone suppression test. Regression analyses of depressive symptoms and cognitive functioning on each HPA axis indicator were performed. In addition we calculated percentages explanation of the association between depressive symptoms and cognition by HPA axis indicators. Depressive symptoms were associated with dysfunction in psychomotor speed, attentional switching and the mean score, as well as with attenuation in diurnal slope value. No association was found between HPA axis activity and cognitive functioning and HPA axis activity did not explain the associations between depressive symptoms and cognition.

Conclusions/Significance

As our study is the first one in this field specific for bipolar patients and changes in HPA-axis activity did not seem to explain the association between severity of depressive symptoms and cognitive functioning in bipolar patients, future studies are needed to evaluate other factors that might explain this relationship.