The glucocorticoid receptor: part of the solution or part of the problem?

Preimplantation maternal stress impairs embryo development by inducing oviductal apoptosis with activation of the Fas system

STUDY QUESTION

What are the mechanisms by which the preimplantation restraint stress (PIRS) impairs embryo development and pregnancy outcome?

SUMMARY ANSWER

PIRS impairs embryo development by triggering apoptosis in mouse oviducts and embryos,and this involves activation of the Fas system.

WHAT IS KNOWN ALREADY

Although it is known that the early stages of pregnancy are more vulnerable than later stages to prenatalstress, studies on the effect of preimplantation stress on embryo developmentare limited. Furthermore, the mechanisms by which psychological stress impairs embryo development are largely unknown. These issues are worth exploring using the mouse PIRS models because restraint of mice is an efficient experimental procedure developed for studies of psychogenic stress.

STUDY DESIGN, SIZE AND DURATION

Mice of Kunming strain, the generalized lymphoproliferative disorder (gld) mice with a germline mutation F273L in FasL in a C57BL/6J genomic background and the wild-type C57BL/6J mice were used. Female and male mice were used 8-10 weeks and 10-12 weeks after birth, respectively. Female mice showing vaginal plugs were paired by weight and randomly assigned to restraint treatments or as controls. For restraint treatment, an individual mouse was put in a micro-cage with food and water available. Control mice remained in their cages with food and water during the time treated females were stressed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Female mice were exposed to PIRS for 48 h starting from 16:00 on the day of vaginal plug detection. At the end of PIRS, levels of glucorticoids (GC), corticotropin-releasing hormone (CRH)and redox potential were measured in serum, while levels of GC, GC receptor (GR), CRH, CRH receptor (CRHR), Fas and Fas ligand (FasL) protein, mRNAs for brain derived neurotrophic factor (BDNF) and insulin-like growth factor-1 (IGF-1), oxidative stress (OS) and apoptosis were examined in oviducts. Preimplantation development and levels of GR, Fas, redox potential and apoptosis were observed in embryos recovered at different times after the initiation of PIRS. The gld mice were used to confirm a role for the Fas system in triggering apoptosis of embryos and oviducts.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to those in control mice, while the number of blastocysts/mouse (5.0 ± 0.7 versus 11.1 ± 0.5), cell number/blastocyst (49.1 ± 1.3 versus 61.5 ± 0.9), percentages of term pregnancy (37.5% versus 90.9%) and litter size (3.7 ± 0.1versus 9.6 ± 0.6) decreased, blood CRH (560 ± 23 versus 455 ± 37 pg/ml), cortisol (27.3 ± 3.4 versus 5 ± 0.5 ng/ml) and OS index (OSI: 2.8 versus 1.7) increased significantly (all P < 0.05) following PIRS. In the oviduct, while levels of CRH (1175 ± 85 versus 881 ± 33 pg/100 mg), cortisol (28.9 ± 1.7 versus14 ± 4 ng/g), CRHR (2.3 ± 0.3 versus 1.0 ± 0.0), FasL (1.31 ± 0.06 versus 1.08 ± 0.05 ng/g), Fas (1.42 ± 0.13 versus 1.0 ± 0.0) and apoptotic cells (19.1 ± 0.5% versus 8.4 ± 0.4%) increased, levels of GR proteins (0.67 ± 0.14 versus 1.0 ± 0.0) and Igf-1 (0.6 ± 0.09 versus 1.0 ± 0.0) and Bdnf (0.73 ± 0.03 versus 1.0 ± 0.0) mRNAs decreased significantly (all P < 0.05 versus control) after PIRS. Mouse embryos expressed GR and Fas at all stages of preimplantation development and embryo OS (GSH/GSSG ratio: 0.88 ± 0.03 versus 1.19 ± 0.13) and annexin-positive cells (blastocysts: 31.4 ± 3.8% versus 10.96 ± 3.4%) increased significantly (P < 0.05) following PIRS. Furthermore, the detrimental effects of PIRS on embryo development and oviductal apoptosis were much reduced in gld mice. Thus, PIRS triggered apoptosis in oviductal cells with activation of the Fas/FasL system. The apoptotic oviductal cells promoted embryo apoptosis with reduced production of IGF-1 and BDNF and increased production of FasL.

LIMITATIONS, REASONS FOR CAUTION

Although important, the conclusions were drawn from limited results obtained using a single model in one species and thus they need further verification using other models and/or in other species. Furthermore, as differences in stressed samples were modest and sometimes not significant between gld and wild-type mice whereas differences between control and stressed samples were always present within gld mice, it is deduced that signaling pathways other than the Fas/FasL system might be involved as well in the PIRS-triggered apoptosis of oviducts and embryos.

WIDER IMPLICATIONS OF THE FINDINGS

The data are important for studies on the mechanisms by which psychological stress affects female reproduction, as FasL expression has been observed in human oviduct epithelium.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This study was supported by grants from the National Basic Research Program of China (Nos. 2014CB138503 and 2012CB944403), the China National Natural Science Foundation (Nos. 31272444 and 30972096) and the Animal breeding improvement program of Shandong Province. All authors declare that their participation in the study did not involve factual or potential conflicts of interests.

Perinatal maternal depression and cortisol function in pregnancy and the postpartum period: a systematic literature review

BACKGROUND

Perinatal depression has a significant impact on both mother and child. However, the influence of hormonal changes during pregnancy and the postpartum period remains unclear. This article provides a systematic review of studies examining the effects of maternal cortisol function on perinatal depression.

METHOD

A systematic search was conducted of six electronic databases for published research on the relationship between cortisol and perinatal depression. The databases included; MEDLINE complete, PsychINFO, SCOPUS, Psychology and Behavioural Sciences, Science Direct and EBSCO, for the years 1960 to May 2015. Risk of bias was assessed and data extraction verified by two investigators.

RESULTS

In total, 47 studies met criteria and studies showed considerable variation in terms of methodology including sample size, cortisol assays, cortisol substrates, sampling processes and outcome measures. Those studies identified as higher quality found that the cortisol awakening response is positively associated with momentary mood states but is blunted in cases of major maternal depression. Furthermore, results indicate that hypercortisolemia is linked to transient depressive states while hypocortisolemia is related to chronic postpartum depression.

DISCUSSION AND CONCLUSION

Future research should aim to improve the accuracy of cortisol measurement over time, obtain multiple cortisol samples in a day and utilise diagnostic measures of depression. Future studies should also consider both antenatal and postnatal depression and the differential impact of atypical versus melancholic depression on cortisol levels, as this can help to further clarify the relationship between perinatal depression and maternal cortisol function across pregnancy and the postpartum period.

The role of glucocorticoid receptor phosphorylation in the model of negative affective states

OBJECTIVES

To develop a structural equation model of negative affectivity (NA) that involves interaction of glucocorticoid receptor (GR) signaling, personality dimensions and recent stressful life events.

METHODS

Seventy participants - 35 diagnosed with major depression and 35 healthy controls, were enrolled in the study. Morning plasma cortisol levels were determined by chemiluminescent immunometric assays. Molecular parameters (total nuclear and cytoplasmatic GR, nuclear GR phosphorylated at serine 211 (pGR-211) and at serine 226 (pGR-226) and cytoplasmic FKBP51) were analysed from peripheral blood lymphocytes by Western blot. NA, personality dimensions and stressful life events were assessed by self-report instruments.

RESULTS

GR signalling parameters had direct independent effect on measures of NA, with pGR-226 levels showing the strongest correlation, followed by FKBP51 and pGR-211 levels. Neuroticism and extraversion also demonstrated strong independent effect on NA, while recent stressful events did not predict NA directly, but demonstrated a significant effect on personality dimensions. Cortisol, total nuclear GR and total cytoplasmatic GR levels were excluded from the model due to non-significant correlations with NA.

CONCLUSIONS

Negative affectivity is a transdiagnostic factor in vulnerability to affective disorders and possible therapeutic target. Molecular signature of negative affectivity should incorporate GR phosphorylation with other known biological underpinnings.

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.

Neurotrophic-priming of glucocorticoid receptor signaling is essential for neuronal plasticity to stress and antidepressant treatment

Neurotrophins and glucocorticoids are robust synaptic modifiers, and deregulation of their activities is a risk factor for developing stress-related disorders. Low levels of brain-derived neurotrophic factor (BDNF) increase the desensitization of glucocorticoid receptors (GR) and vulnerability to stress, whereas higher levels of BDNF facilitate GR-mediated signaling and the response to antidepressants. However, the molecular mechanism underlying neurotrophic-priming of GR function is poorly understood. Here we provide evidence that activation of a TrkB-MAPK pathway, when paired with the deactivation of a GR-protein phosphatase 5 pathway, resulted in sustained GR phosphorylation at BDNF-sensitive sites that is essential for the transcription of neuronal plasticity genes. Genetic strategies that disrupted GR phosphorylation or TrkB signaling in vivo impaired the neuroplasticity to chronic stress and the effects of the antidepressant fluoxetine. Our findings reveal that the coordinated actions of BDNF and glucocorticoids promote neuronal plasticity and that disruption in either pathway could set the stage for the development of stress-induced psychiatric diseases.

Neuroimmune mechanisms of depression

Current diagnosis of depression is based solely on behavioral symptomatology. The available US Food and Drug Administration-approved treatments for depression have come from serendipitous discovery and are ineffective in nearly 30-50% of patients, which is thought to reflect a lack of specificity in targeting underlying pathophysiological mechanisms. Recent evidence has identified depression-related disruptions in a neuroimmune axis that interfaces the immune system and CNS to control behavior. This Review examines the evidence in patients and in animal models of depression that demonstrates how the peripheral immune system acts on the brain to alter an individual's response to stress, ultimately contributing to their vulnerability to mood disorders.

Insufficient glucocorticoid signaling and elevated inflammation in coronary heart disease patients with comorbid depression

Coronary heart disease (CHD) and depression are very common and often co-existing disorders. In addition to psychological and social morbidity, depression exacerbates adverse cardiac outcomes in CHD patients. Inflammation has been proposed as one of the mechanisms involved in the association between these two debilitating diseases. Therefore, the present study aimed to evaluate inflammatory responses as well as to investigate the pathophysiological mechanisms underlying the putative inflammatory activation in CHD patients with and without depression, by assessing the function of two important biological factors regulating inflammation, the hypothalamus-pituitary-adrenal (HPA) axis and the glucocorticoid receptor (GR). Eighty-three CHD patients with (n=28) and without (n=55) comorbid depression were recruited from primary care services in South London. Depression status was assessed by means of Clinical Interview Schedule Revised for diagnosis of depression, and Beck Depression Inventory for the presence of depressive symptoms. Serum C-reactive protein (CRP), plasma vascular endothelial growth factor (VEGF), and plasma and salivary cortisol were measured using commercially available ELISA kits. Gene expression of GR and interleukin-6 (IL-6) were conducted via qPCR. GR sensitivity was evaluated in vitro in isolated peripheral blood mononuclear cells using the dexamethasone inhibition of lipopolysaccharide-stimulated IL-6 levels. Serum levels of kynurenine pathway metabolites were measured using high performance liquid chromatography. Our results show that CHD patients with depression had higher levels of CRP, IL-6 gene expression, and VEGF compared with CHD non-depressed, as well as lower plasma and saliva cortisol levels. The CHD depressed group also exhibited a reduction in GR expression and sensitivity. Finally, tryptophan levels were significantly lower in patients with depression, who also showed an increased kynurenine/tryptophan ratio. In conclusion, CHD patients with depression had elevated levels of inflammation in the context of HPA axis hypoactivity, GR resistance, and increased activation of the kynurenine pathway. Reduced cortisol bioavailability and attenuated glucocorticoid responsiveness due to decreased expression and sensitivity of GR may lead to insufficient glucocorticoid signaling and thus elevation of inflammation in these patients.

Early life adversity and the epigenetic programming of hypothalamic-pituitary-adrenal function

We review studies with human and nonhuman species that examine the hypothesis that epigenetic mechanisms, particularly those affecting the expression of genes implicated in stress responses, mediate the association between early childhood adversity and later risk of depression. The resulting studies provide evidence consistent with the idea that social adversity, particularly that involving parent-offspring interactions, alters the epigenetic state and expression of a wide range of genes, the products of which regulate hypothalamic-pituitary-adrenal function. We also address the challenges for future studies, including that of the translation of epigenetic studies towards improvements in treatments.

Hypothalamic-pituitary-adrenal axis function during perinatal depression

Abnormal function of the hypothalamic-pituitary-adrenal (HPA) axis is an important pathological finding in pregnant women exhibiting major depressive disorder. They show high levels of cortisol pro-inflammatory cytokines, hypothalamic-pituitary peptide hormones and catecholamines, along with low dehydroepiandrosterone levels in plasma. During pregnancy, the TH2 balance together with the immune system and placental factors play crucial roles in the development of the fetal allograft to full term. These factors, when altered, may generate a persistent dysfunction of the HPA axis that may lead to an overt transfer of cortisol and toxicity to the fetus at the expense of reduced activity of placental 11β-hydroxysteroid dehydrogenase type 2. Epigenetic modifications also may contribute to the dysregulation of the HPA axis. Affective disorders in pregnant women should be taken seriously, and therapies focused on preventing the deleterious effects of stressors should be implemented to promote the welfare of both mother and baby.

High fat feeding is associated with stimulation of the hypothalamic-pituitary-adrenal axis and reduced anxiety in the rat

Previous studies have shown that diet-induced obesity is associated with insulin resistance and impaired feedback control of the hypothalamic-pituitary-adrenal (HPA) axis. The objective of this study was to test the hypothesis that hyper-secretion of glucocorticoid, evoked by feeding rats a high fat (HF) diet for 12 weeks, also influences behavioural and neural responses to the elevated plus-maze (EPM) test of anxiety. HF-fed animals exhibited anxiolytic-like behaviour in the EPM but were also hyperactive in this test. Covariant analysis established that the anxiolytic-like behaviour was not secondary to the increase in activity. The HF diet significantly increased basal levels of plasma corticosterone. The groups exposed to the EPM also displayed increased plasma corticosterone levels compared to the relevant control group, although the increment was smaller in the HF-fed animals. Glucocorticoid receptor (GR) immunoreactivity in the cytoplasmic fraction of parietal cortex and hypothalamus and the particulate fraction of the parietal cortex were increased by HF feeding. The behavioural changes evoked by HF feeding did not correlate significantly with changes in GR immunoreactivity in each treatment group or 5-HT turnover in the brain areas studied. It is concluded that anxiolytic properties evoked in the EPM by high fat feeding are unlikely to be related to the changes in HPA function seen in animals fed this diet.

Antidepressant-like effects of salidroside on olfactory bulbectomy-induced pro-inflammatory cytokine production and hyperactivity of HPA axis in rats

Salidroside (SA) is the primary bioactive marker compound in the standardized extracts from Rhodiola rosea. Although it has potential antidepressant activity in a rat behavioral despair model, the mechanisms of antidepressant effect for SA remain unclear. The objective of this study was to evaluate the antidepressant effects of SA and to discuss the potential mechanisms in olfactory bulbectomized (OBX) rats. SA of 20, 40 mg/kg (p.o.) for 2 weeks notably alleviated OBX-induced hyperactivity in open field test, decreased immobility time in TST and FST. Chronic treatment with SA could remarkably reduce TNF-α and IL-1β levels in hippocampus. Western blot showed that SA could markedly increase glucocorticoid receptor (GR) and brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Besides, SA could also attenuate corticotropin-releasing hormone (CRH) expression in hypothalamus, as well as reducing significantly the levels of serum corticosterone. In conclusion, this study demonstrated that OBX rats treated with SA could significantly improve the depressive-like behaviors. The antidepressant mechanisms of SA might be associated with its anti-inflammatory effects and the regulation of HPA axis activity. Reversal of abnormalities of GR may be partly responsible for those effects. These findings suggested that SA might become a beneficial agent to prevent and treat the depression.

Inflammatory biomarker profiles of mental disorders and their relation to clinical, social and lifestyle factors

In the last few decades, mental health research has increasingly provided evidence supporting the role of inflammation in pathogenesis, course and treatment of mental disorders. With such a steep incline of research, resulting in a wealth of emerged findings, it has become difficult to follow developments within the field. The present review sets out to present the recent developments and to give an overview of the inflammatory profiles of depression, psychosis and bipolar disorder, as well as variations within these disorders. Moreover, mediating factors such as social environment and childhood experience are discussed, both in terms of their potential in elucidating the complex interface between the inflammation and other closely related biological systems, as well as the possibly confounding impact of various lifestyle factors. Whilst many issues in this fascinating area of research remain to be fully understood and elaborated, all current evidence suggests that inflammation plays a key role in mental disorders and may open up novel avenues for clinical treatment.

The selective glucocorticoid receptor antagonist CORT 108297 decreases neuroendocrine stress responses and immobility in the forced swim test

Pre-clinical and clinical studies have employed treatment with glucocorticoid receptor (GR) antagonists in an attempt to limit the deleterious behavioral and physiological effects of excess glucocorticoids. Here, we examined the effects of GR antagonists on neuroendocrine and behavioral stress responses, using two compounds: mifepristone, a GR antagonist that is also a progesterone receptor antagonist, and CORT 108297, a specific GR antagonist lacking anti-progestin activity. Given its well-documented impact on neuroendocrine and behavioral stress responses, imipramine (tricyclic antidepressant) served as a positive control. Male rats were treated for five days with mifepristone (10mg/kg), CORT 108297 (30mg/kg and 60mg/kg), imipramine (10mg/kg) or vehicle and exposed to forced swim test (FST) or restraint stress. Relative to vehicle, imipramine potently suppressed adrenocorticotropin hormone (ACTH) responses to FST and restraint exposure. Imipramine also decreased immobility in the FST, consistent with antidepressant actions. Both doses of CORT 108297 potently suppressed peak corticosterone responses to FST and restraint stress. However, only the higher dose of CORT 108297 (60mg/kg) significantly decreased immobility in the FST. In contrast, mifepristone induced protracted secretion of corticosterone in response to both stressors, and modestly decreased immobility in the FST. Taken together, the data indicate distinct effects of each compound on neuroendocrine stress responses and also highlight dissociation between corticosterone responses and immobility in the FST. Within the context of the present study, our data suggest that CORT 108297 may be an attractive alternative for mitigating neuroendocrine and behavioral states associated with excess glucocorticoid secretion.

The Interface of Stress and the HPA Axis in Behavioural Phenotypes of Mental Illness

Abnormalities of hypothalamic-pituitary-adrenal (HPA) axis function are one of the most consistent biological findings across several mental disorders, but many of the mechanisms underlying this abnormality as well as the potential contribution to behavioural phenotypes remain only partially understood. Interestingly, evidence suggests a U-curve, with dysregulation of the HPA axis towards both hyper- or hypoactivity manifesting as a risk to mental wellbeing. This review will elaborate on both the clinical and molecular role of the neuroendocrine stress system in depressive, psychotic and post-traumatic stress disorders and present some of the most recent findings that have shed light on the complex interface between environmental stressors, molecular mechanisms and clinical presentation. Crucially, plasticity of the HPA axis confers both vulnerability to adverse events, particularly so in early developmental stages, as well as hope for the treatment of mental disorder, as evidenced by changes in HPA functioning associated with remission of symptoms.

Adult hippocampal neurogenesis in depression: behavioral implications and regulation by the stress system

Adult hippocampal neurogenesis, the birth of new neurons in the dentate gyrus of the adult brain, can be regulated by stress and antidepressant treatment, and has consistently been implicated in the behavioral neurobiology of stress-related disorders, especially depression and anxiety. A reciprocal relationship between hippocampal neurogenesis and the hypothalamus-pituitary-adrenal (HPA) axis has recently been suggested, which may play a crucial role in the development and in the resolution of depressive symptoms. This chapter will review some of the existing evidence for stress- and antidepressant-induced changes in adult hippocampal neurogenesis, and critically evaluate the behavioral effects of these changes for depression and anxiety. The potential role of neurogenesis as a neurobiological mechanism for sustained remission from depressive symptoms will be discussed, integrating existing data from clinical studies, animal work, and cellular models. The effect of glucocorticoid hormones and the glucocorticoid receptor (GR) will thereby be evaluated as a central mechanism by which stress and antidepressant may exert their opposing effects on neurogenesis, and ultimately, on mood and behavior.

The neurobiological bases of memory formation: from physiological conditions to psychopathology

The formation of long-term memories is a function necessary for an adaptive survival. In the last two decades, great progress has been made in the understanding of the biological bases of memory formation. The identification of mechanisms necessary for memory consolidation and reconsolidation, the processes by which the posttraining and postretrieval fragile memory traces become stronger and insensitive to disruption, has indicated new approaches for investigating and treating psychopathologies. In this review, we will discuss some key biological mechanisms found to be critical for memory consolidation and strengthening, the role/s and mechanisms of memory reconsolidation, and how the interference with consolidation and/or reconsolidation can modulate the retention and/or storage of memories that are linked to psychopathologies.

Association between cortisol awakening response and memory function in major depression

BACKGROUND

While impaired memory and altered cortisol secretion are characteristic features of major depression, much less is known regarding the impact of antidepressant medication. We examined whether the cortisol awakening response (CAR) is increased in depressed patients with and without medication compared with healthy controls (HC) and whether CAR is associated with memory function in each group.

METHOD

We examined 21 patients with major depression without medication, 20 depressed patients on antidepressant treatment, and 41 age-, sex- and education-matched healthy subjects. We tested verbal (Auditory Verbal Learning Task) and visuospatial (Rey figure) memory and measured CAR on two consecutive days.

RESULTS

Patient groups did not differ in severity of depression. We found a significant effect of group (p = 0.03) for CAR. Unmedicated patients exhibited a greater CAR compared with medicated patients (p = 0.04) with no differences between patient groups and HC. We found a significant effect of group for verbal (p = 0.03) and non-verbal memory (p = 0.04). Unmedicated patients performed worse compared with medicated patients and HC in both memory domains. Medicated patients and HC did not differ. Regression analyses revealed a negative association between CAR and memory function in depressed patients, but not in HC.

CONCLUSIONS

While in unmedicated depressed patients the magnitude of CAR is associated with impaired memory, medicated patients showed a smaller CAR and unimpaired cognitive function compared with HC. Our findings are compatible with the idea that antidepressants reduce CAR and partially restore memory function even if depressive psychopathology is still present.

Are BDNF and glucocorticoid activities calibrated?

One hypothesis to account for the onset and severity of neurological disorders is the loss of trophic support. Indeed, changes in the levels and activities of brain-derived neurotrophic factor (BDNF) occur in numerous neurodegenerative and neuropsychiatric diseases. A deficit promotes vulnerability whereas a gain of function facilitates recovery by enhancing survival, synapse formation and synaptic plasticity. Implementation of 'BDNF therapies', however, faces numerous methodological and pharmacokinetic issues. Identifying BDNF mimetics that activate the BDNF receptor or downstream targets of BDNF signaling represent an alternative approach. One mechanism that shows great promise is to study the interplay of BDNF and glucocorticoid hormones, a major class of natural steroid secreted during stress reactions and in synchrony with circadian rhythms. While small amounts of glucocorticoids support normal brain function, excess stimulation by these steroid hormones precipitates stress-related affective disorders. To date, however, because of the paucity of knowledge of underlying cellular mechanisms, deleterious effects of glucocorticoids are not prevented following extreme stress. In the present review, we will discuss the complementary roles shared by BDNF and glucocorticoids in synaptic plasticity, and delineate possible signaling mechanisms mediating these effects.

Mineralocorticoid receptor antagonist spironolactone prevents chronic corticosterone induced depression-like behavior

High level of serum corticosteroid is frequently associated with depression, in which a notable HPA (hypothalamus-pituitary-adrenal) axis hyperactivity is often observed. There are two types of corticosteroid receptors expressed in the hippocampus that provide potent negative feedback regulation on the HPA axis but dysfunction during depression, i.e. the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). The balance between hippocampal MR and GR during chronic stress plays an important role in the occurrence of depression. The aim of this study is to explore if chronic corticosterone administration would induce depression-like behavior and affect the expression and function of hippocampal MR and GR, in addition to assess whether manipulation of corticosteroid receptors would modulate depressive behaviors. Hence, mice were treated with corticosterone (40 mg/kg) for 21 days followed by assessment in a battery of depression-like behaviors. The results show that chronic corticosterone-treated animals displayed an increased immobility time in a forced-swimming test, decreased preference to sucrose solution and novel object recognition performance, and enhanced hippocampal serotonin but decreased MR expression in both hippocampus and hypothalamus. On the other hand, co-administration of MR antagonist, spironolactone (25mg/kg, i.p. × 7 days) in corticosteroid-treated animals reduced immobility time in a forced-swimming test and improved performance in a novel object recognition test. In conclusion, we demonstrate that chronic corticosterone treatment triggers several depression-like behaviors, and in parallel, down-regulates MR expression in the hippocampus and hypothalamus. Administration of an MR antagonist confers an anti-depressant effect in chronic corticosterone-treated animals.

Antidepressant therapy in epilepsy: can treating the comorbidities affect the underlying disorder?

There is a high incidence of psychiatric comorbidity in people with epilepsy (PWE), particularly depression. The manifold adverse consequences of comorbid depression have been more clearly mapped in recent years. Accordingly, considerable efforts have been made to improve detection and diagnosis, with the result that many PWE are treated with antidepressant drugs, medications with the potential to influence both epilepsy and depression. Exposure to older generations of antidepressants (notably tricyclic antidepressants and bupropion) can increase seizure frequency. However, a growing body of evidence suggests that newer ('second generation') antidepressants, such as selective serotonin reuptake inhibitors or serotonin-noradrenaline reuptake inhibitors, have markedly less effect on excitability and may lead to improvements in epilepsy severity. Although a great deal is known about how antidepressants affect excitability on short time scales in experimental models, little is known about the effects of chronic antidepressant exposure on the underlying processes subsumed under the term 'epileptogenesis': the progressive neurobiological processes by which the non-epileptic brain changes so that it generates spontaneous, recurrent seizures. This paper reviews the literature concerning the influences of antidepressants in PWE and in animal models. The second section describes neurobiological mechanisms implicated in both antidepressant actions and in epileptogenesis, highlighting potential substrates that may mediate any effects of antidepressants on the development and progression of epilepsy. Although much indirect evidence suggests the overall clinical effects of antidepressants on epilepsy itself are beneficial, there are reasons for caution and the need for further research, discussed in the concluding section.

Exogenous glucocorticoids decrease subgenual cingulate activity evoked by sadness

The glucocorticoid hormone cortisol is known to have wide-ranging effects on a variety of physiological systems, including the morphology and physiology of the amygdala and hippocampus. Disruptions of cortisol regulation and signaling are also linked with psychiatric disorders involving emotional disturbances. Although there is much evidence to suggest a relationship between cortisol signaling and the brain physiology underlying emotion, few studies have attempted to test for direct effects of cortisol on the neurophysiology of emotion. We administered exogenous synthetic cortisol (hydrocortisone, HCT) using two different dosing regimens (25 mg/day over 4 days, 100 mg single dose), in a double-blind placebo-controlled functional magnetic resonance imaging (fMRI) study. During fMRI scanning, healthy subjects viewed images designed to induce happy, sad, and neutral emotional states. Subjective emotional reactions were collected for each experimental stimulus after fMRI scanning. Mood ratings were also collected throughout the 4 days of the study. Both dose regimens of HCT resulted in decreased subgenual cingulate activation during sadness conditions. The 25 mg/day regimen also resulted in higher arousal ratings of sad stimuli. No effects of HCT were observed on any mood ratings. Few reliable effects of HCT were observed on brain activity patterns or subjective emotional responses to stimuli that were not sad. The inhibitory effects of cortisol on sadness-induced subgenual cingulate activity may have critical relevance to the pathophysiology of major depression, as both subgenual hyperactivity and decreased sensitivity to cortisol signaling have been documented in patients with depression.

Glucocorticoid receptor and FKBP5 expression is altered following exposure to chronic stress: modulation by antidepressant treatment

Major depression is thought to originate from the interaction between susceptibility genes and adverse environmental events, in particular stress. The hypothalamus-pituitary-adrenal (HPA) axis is the major system involved in stress response and its dysregulation is an important element in the pathogenesis of depression. The stress response is therefore finely tuned through a series of mechanisms that control the trafficking of glucocorticoid receptors (GRs) to the nucleus, including binding to the chaperone protein FKBP5 and receptor phosphorylation, suggesting that these elements may also be affected under pathologic conditions. On these bases, we investigated FKBP5 and GR expression and phosphorylation in the hippocampus (ventral and dorsal) and in the prefrontal cortex of rats exposed to chronic mild stress (CMS) and we analyzed the effect of a concomitant antidepressant treatment. We found that animals exposed to CMS show increased expression of FKBP5 as well as enhanced cytoplasmic levels of GR, primarily in ventral hippocampus and prefrontal cortex. Chronic treatment with the antidepressant duloxetine is able to normalize such alterations, mainly in the prefrontal cortex. Moreover, we demonstrate that CMS-induced alterations of GR trafficking and transcription may be sustained by changes in receptor phosphorylation, which are also modulated by pharmacological intervention. In summary, while GR-related changes after CMS might be relevant for the depressive phenotype, the ability of antidepressant treatment to correct some of these alterations may contribute to the normalization of HPA axis dysfunctions associated with stress-related disorders.

Phosphorylation of leukocyte glucocorticoid receptor in patients with current episode of major depressive disorder

The impaired glucocorticoid receptor (GR) signaling has long been considered one of the cornerstones in understanding the pathophysiology of depression. Since the phosphorylation of GR is very important for GR function, in this study we investigated whether GR phosphorylation at serine 211 (pGR-S211) and serine 226 (pGR-S226) is altered in patients with current episode of major depressive disorder (MDD). Particularly, in 30 MDD patients and 35 controls we assessed the levels of nuclear total GR (tGR), pGR-S211 and pGR-S226 in peripheral blood mononuclear cells (PBMC) using Western blot technique, along with plasma cortisol concentrations from the same blood samples. Our results demonstrated increased phosphorylation of GR at S226 (p<0.001) and, to a less extent, at S211 (p<0.05) in MDD patients compared to controls. Consequently, the pGR-S211/pGR-S226 ratio was decreased (p<0.05) implying reduced transcriptional activity of GR in MDD patients. MDD subjects had higher cortisol levels than controls and cortisol concentrations were positively correlated with PBMC pGR-S226 levels from the same blood samples. There was no difference in the levels of tGR between MDD and control subjects. The study showed that altered phosphorylation of GR could contribute to impaired GR function related to the pathophysiology of depression.

Circadian activity of the hypothalamic-pituitary-adrenal axis is differentially affected in the rat chronic mild stress model of depression

The altered activity of the hypothalamic-pituitary-adrenal (HPA) axis is often observed in stress-related disorders. According to the literature, about 60% of patients with major depressive disorder elicit high levels of cortisol. It is still unclear why high cortisol levels are not observed in all patients. In this study, we used the chronic mild stress (CMS) rat model of depression, which is based on continuous exposure to unpredictable stressors, to track longitudinal changes in HPA function using fecal corticosterone metabolites (FCM) as a read out. The dexamethasone suppression test was used to assess negative feedback inhibition of the HPA axis. Our results show (1) a disturbance in diurnal corticosterone rhythm measured as fluctuations of the diurnal FCM peak, (2) differences in corticosterone levels between stress-susceptible and stress-resilient animals, (3) recovery of diurnal corticosterone rhythm after 8 weeks of CMS, and (4) alterations in sensitivity to dexamethasone in negative feedback regulation of corticosterone secretion during the time course of CMS. Thus, a disruption of HPA axis circadian rhythmicity coincides with the initial state in the development of depression-like behavior. This chronobiological abnormality, as well as the hypersecretion of corticosterone, is state, rather than trait, dependent.

Sex, stress, and mood disorders: at the intersection of adrenal and gonadal hormones

The risk for neuropsychiatric illnesses has a strong sex bias, and for major depressive disorder (MDD), females show a more than 2-fold greater risk compared to males. Such mood disorders are commonly associated with a dysregulation of the hypothalamo-pituitary-adrenal (HPA) axis. Thus, sex differences in the incidence of MDD may be related with the levels of gonadal steroid hormone in adulthood or during early development as well as with the sex differences in HPA axis function. In rodents, organizational and activational effects of gonadal steroid hormones have been described for the regulation of HPA axis function and, if consistent with humans, this may underlie the increased risk of mood disorders in women. Other developmental factors, such as prenatal stress and prenatal overexposure to glucocorticoids can also impact behaviors and neuroendocrine responses to stress in adulthood and these effects are also reported to occur with sex differences. Similarly, in humans, the clinical benefits of antidepressants are associated with the normalization of the dysregulated HPA axis, and genetic polymorphisms have been found in some genes involved in controlling the stress response. This review examines some potential factors contributing to the sex difference in the risk of affective disorders with a focus on adrenal and gonadal hormones as potential modulators. Genetic and environmental factors that contribute to individual risk for affective disorders are also described. Ultimately, future treatment strategies for depression should consider all of these biological elements in their design.

Pituitary volume, stress reactivity and genetic risk for psychotic disorder

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, associated with increased pituitary volume, may mediate observed alterations in stress reactivity in patients with psychotic disorder. We examined the association between pituitary volume, real-life stress reactivity and genetic liability for psychotic disorder.

METHOD

Pituitary volumes were derived from magnetic resonance imaging (MRI) scans of 20 patients with psychotic disorder, 37 non-psychotic siblings of these patients, and 32 controls. The Experience Sampling Method (ESM) was used to measure emotional stress reactivity [changes in negative affect (NA) associated with daily life stress] in the three groups, and biological stress reactivity (changes in cortisol associated with daily life stress) in siblings and controls. Interactions between group, stress and pituitary volume in models of NA and cortisol were examined.

RESULTS

Groups did not differ in pituitary volume. Patients showed significantly higher emotional stress reactivity than siblings and controls. In addition, emotional stress reactivity increased with increasing pituitary volume to a greater degree in patients than in controls and siblings. Siblings had higher cortisol levels than controls but did not show increased cortisol reactivity to stress. There was no interaction between pituitary volume, stress and group in the model of cortisol.

CONCLUSIONS

Higher pituitary volume was associated with increased emotional stress reactivity in patients with psychotic disorder, siblings and controls. The association was significantly stronger in the patient group, suggesting a process of progressive sensitization mediating clinical outcome.

Pathophysiology of hypercortisolism in depression: pituitary and adrenal responses to low glucocorticoid feedback

OBJECTIVE

To test three theories of hypercortisolemia in depression-hypothalamic overdrive, impaired glucocorticoid feedback, or autonomous cortisol production.

METHOD

We applied an overnight low-cortisol feedback strategy by administering metyrapone to hypercortisolemic depressed in-patients and control subjects.

RESULTS

Under metyrapone, the increases of plasma adrenocorticotropic hormone (ACTH) concentrations and of basal and pulsatile ACTH secretion were not exaggerated in hypercortisolemic depressed patients compared with control subjects. ACTH approximate entropy (ApEn) did not differ at baseline or under metyrapone. Thus, neither hypothalamic overdrive nor irregular ACTH secretion was seen. We did not detect impaired cortisol feedback: the ACTH response was not reduced, and ApEn measures that are sensitive to feedback changes were comparable in both groups. Metyrapone disrupted cortisol secretory regularity in depressed and control subjects. On the baseline day, basal cortisol secretion was significantly increased and was highly irregular (high ApEn), and ACTH-cortisol cross-ApEn was markedly elevated in high-cortisol patients.

CONCLUSION

Classical feed-forward overdrive and impaired feedback theories of hypercortisolemia in depression were not supported. Depressive hypercortisolemia may result from alternative pathophysiological mechanisms involving irregular basal hypersecretion of cortisol, associated with adrenal enlargement, possibly through splanchnic sympathetic activation of the adrenal cortex.

Central glucocorticoid receptor-mediated effects of the antidepressant, citalopram, in humans: a study using EEG and cognitive testing

Our previous work in cellular and animal models has shown that antidepressants activate glucocorticoid receptor (GR) translocation, induce GR down-regulation, and decrease GR-mediated effects in the presence of GR agonists. However, whether these effects can be extrapolated to the human brain is still unclear. In this study, the effects of four days of treatment with the antidepressant, citalopram (20 mg/day), or placebo, were assessed in a double-blind, placebo-controlled, cross-over study. Central GR-mediated effects were examined by the effects of a single dose of cortisol (30 mg, orally) on two measures known to be sensitive to glucocorticoid administration: EEG alpha power and working memory function. Twenty healthy male subjects aged between 18 and 33 years participated to the study. The results suggest that GR activation by antidepressants, and the subsequent decrease in GR-mediated effects in the presence of GR agonists, indeed occurs in the human brain. Specifically, pre-treatment with citalopram decreased the well-known ability of cortisol to increase EEG alpha power and to impair working memory: cortisol-induced increase in EEG alpha power was (anteriorly) +15 to +20% (p=0.01) after placebo and +5 to +8% (p>0.5) after citalopram; and cortisol-induced increase in working memory errors was (at level 12, on average) 2.50 vs. 4.55 (p<0.05) after placebo and 4.10 vs. 3.35 (p>0.05) after citalopram. No effects were detected on alerting. These results are consistent with the notion that citalopram treatment activates GR translocation and inhibits the functional consequences of the subsequent cortisol administration. Our study further emphasizes the importance of the GR as a target for antidepressant action in humans.

Glucocorticoid treatment and impaired mood, memory and metabolism in people with diabetes: the Edinburgh Type 2 Diabetes Study

OBJECTIVE

Both type 2 diabetes and glucocorticoid therapy are highly prevalent. Although people with type 2 diabetes may be more susceptible to adverse effects of glucocorticoids, and it is recommended that glucocorticoid therapy is avoided for fear of worsening glycaemic control, the extent to which this advice is followed and the consequences when glucocorticoids are prescribed are poorly documented. The aim was to assess the characteristics of people with type 2 diabetes prescribed glucocorticoids in a real-world setting and to quantify resulting adverse effects.

DESIGN

Cross-sectional cohort study.

METHODS

Cardiometabolic variables, body fat distribution, cognitive function and mood were studied in the 1066 participants of the Edinburgh Type 2 Diabetes Study, of whom 162 (15%) were taking systemic, topical or inhaled glucocorticoids.

RESULTS

Glucocorticoid therapy was more common in women and in smokers but was not avoided in patients with diabetic complications or cardiovascular risk factors. People taking glucocorticoids were more centrally obese with slightly higher HbA1c and total serum cholesterol but were no more likely to have hepatic steatosis or hypertension. Glucocorticoid treatment was associated with substantially lower mood and greater anxiety. Women taking glucocorticoid therapy were twice as likely to report depressive symptoms compared with those not taking treatment. Glucocorticoid therapy was also associated with poorer cognitive function among those with subclinical atherosclerosis, as indicated by low ankle-brachial pressure index.

CONCLUSIONS

Glucocorticoids are prescribed commonly for people with type 2 diabetes despite being associated with adverse indices of glycaemic control, cardiovascular risk factors, mood and cognitive function.

Depression and mortality in end-stage renal disease

End-stage renal disease is growing in prevalence and incidence. With technical advancements, patients are living longer on hemodialysis. Depression is the most prevalent comorbid psychiatric condition, estimated at about 25% of end-stage renal disease samples. The identification and assessment of depression are confounded by the overlap between depression symptomatology and uremia. Several recent studies have employed time-varying models and identified a significant association between depression and mortality. Due to the high prevalence of depression and the potential impact on survival, well-constructed investigations are warranted.

Assessment of the hypothalamic-pituitary-adrenal axis activity: glucocorticoid receptor and mineralocorticoid receptor function in depression with early life stress - a systematic review

OBJECTIVE

The mechanisms involved in the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, especially in the functioning of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) in depressed patients, are not well elucidated. The objective of this study was to conduct a systematic review of articles that assess the HPA axis activity from GR and MR in depressed patients and healthy controls with or without early life stress.

METHODS

We conducted a systematic review of articles in PubMed, SCOPUS and SciELO published between 2000 and 2011, using the following search terms: child abuse, depression, HPA axis, dexamethasone, prednisolone, fludrocortisone and spironolactone. Thirty-four papers were selected for this review.

RESULTS

Most studies identified in this review used the dexamethasone/corticotropin-releasing hormone test and dexamethasone suppression test. In these studies, hypercortisolaemia was associated with depression. We identified three studies with the Prednisolone suppression test, only one study with the use of fludrocortisone and one with spironolactone. This review found nine studies that evaluated the HPA axis in individuals with early life stress.

CONCLUSIONS

The majority of the studies assessed in this review show that early life stress leads to permanent changes in the HPA axis and may lead to development of depression in adults. The most consistent findings in the literature show increased activity of the HPA axis in depression associated with hypercortisolaemia and reduced inhibitory feedback. These findings suggest that this dysregulation of the HPA axis is partially attributable to an imbalance between GR and MR. Evidences have consistently showed that GR function is impaired in major depression, but few studies have assessed the activity of MR in depression and early life stress.

Bipolar disorder

Bipolar disorder is a serious disorder of mood that is associated with considerable psychosocial and economic morbidity. Even though it is more common than previously thought, it has until relatively recently been somewhat neglected in terms of research when compared to disorders such as schizophrenia and major depression. Recent advances in the fields of nosology, epidemiology, and molecular genetics in particular have begun to unravel some of the complexity of this disorder and the next few years are likely to witness substantial changes to the ways in which the broad spectrum of bipolar disorders is diagnosed and managed.

Inflammation and depression

Major depressive disorder (MDD) is a complex illness and it is likely that alterations in several interacting systems underlie its pathogenesis. Numerous hypotheses have been proposed to elucidate its origins. The inflammatory hypothesis emphasises the role of psycho-neuroimmunological dysfunctions. This is based on several observations: subsets of MDD patients have an altered peripheral immune system, with impaired cellular immunity and increased levels of proinflammatory cytokines; cytokines can influence neurotransmitter metabolism, neuroendocrine function and regional brain activity, all of which are relevant to depression; acute administration of cytokines causes sickness behaviour which shares features with depression, and patients undergoing cytokine treatment develop depressive symptoms. In this chapter, we discuss the evidence linking inflammation and MDD, looking at data from clinical and animal studies, the role of stress, possible mechanisms and the involvement of genetic polymorphisms. Further understanding of pathways involved is still needed. This will be vital for the identification of new drug targets and preventative strategies.

Evidence for the involvement of the glucocorticoid receptor gene in bipolar disorder in an isolated northern Swedish population

OBJECTIVES

Dysfunction of the hypothalamus-pituitary-adrenal (HPA) axis is one of the most consistent findings in the pathophysiology of mood disorders. The potential role of genes related to HPA axis function has been investigated extensively in major depression. However, in bipolar disorder (BPD) such studies are scarce. We performed a systematic HapMap-based association study of six genes crucial for HPA axis function in relation to BPD.

METHODS

Haplotype tagging single nucleotide polymorphisms (htSNPs) were selected in order to identify all haplotypes with a frequency of more than 1% in the genes encoding the glucocorticoid receptor (GR), mineralocorticoid receptor (MR), corticotrophin releasing hormone receptor 1 (CRH-R1) and 2 (CRH-R2), CRH binding protein (CRH-BP), and FK binding protein 5 (FKBP5). This resulted in a total selection of 225 SNPs that were genotyped and analyzed in 309 BPD patients and 364 matched control individuals all originating from an isolated northern Swedish population.

RESULTS

Consistent evidence for an association with BPD was found for NR3C1, the gene encoding GR. Almost all SNPs in two adjacent haplotype blocks contributed to the positive signal, comprised of significant single marker, sliding window, and haplotype-specific p-values. All these results point to a moderately frequent (10-15%) susceptibility haplotype covering the entire coding region and 3' untranslated region (UTR) of NR3C1.

CONCLUSIONS

This study contributes to the growing evidence for a role of the glucocorticoid receptor gene (NR3C1) in vulnerability to mood disorders, and BPD in particular, and warrants further in vitro investigation of the at-risk haplotypes with respect to disease etiology. However, this association might be restricted to this specific population, as it is observed in a rather small sample from an isolated population without replication, and data from large meta-analyses for genome-wide association studies in BPD do not show the GR as a very strong candidate.

Serum brain-derived neurotrophic factor and glucocorticoid receptor levels in lymphocytes as markers of antidepressant response in major depressive patients: a pilot study

Depressive patients often have altered cortisol secretion, an effect that likely derives from impaired activity of the glucocorticoid receptor (GR), the main regulator of the hypothalamus-pituitary-adrenal (HPA) axis. Glucocorticoids reduce the levels of brain-derived neurotrophic factor (BDNF), a downstream target of antidepressants. Antidepressants promote the transcriptional activity of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), a regulator of BDNF expression. To identify potential biomarkers for the onset of antidepressant action in depressive patients, GR and phospho-CREB (pCREB) levels in lymphocytes and serum BDNF levels were repeatedly measured during the course of antidepressant treatment. Thirty-four depressed outpatients (10 male and 24 female) were treated with venlafaxine (75mg/day), and individuals exhibiting a 50% reduction in their baseline 17-Item Hamilton Depression Rating Scale score by the 6th week of treatment were considered responders. Responders showed an early improvement in parallel with a rise in BDNF levels during the first two weeks of treatment. Non-responders showed increased GR levels by the third week and reduced serum BDNF by the sixth week of treatment. In contrast, venlafaxine did not affect levels of pCREB. We conclude that levels of BDNF in serum and GR levels in lymphocytes may represent biomarkers that could be used to predict responses to venlafaxine treatment.

Glucocorticoid receptor gene haplotype predicts increased risk of hospital admission for depressive disorders in the Helsinki birth cohort study

BACKGROUND

Although glucocorticoid receptors (GR) are involved in mediating hypothalamic-pituitary-adrenal-axis functioning, which is altered in acute depression, data on associations between GR gene (NR3C1) polymorphisms and depression are scarce. We examined if single nucleotide polymorphisms (SNPs) and their haplotypes spanning the entire NR3C1 are associated with depressive disorders and with self-reported depressive symptoms in adulthood.

METHODS

We successfully genotyped 10 SNPs spanning the NR3C1, and performed SNP and haplotype analyses in 1,075 women and 928 men participating in the Helsinki birth cohort study. Diagnoses of depressive disorders were extracted from the Finnish Hospital Discharge Register covering a 35-year period from early to late adulthood. In addition, depressive symptoms were self-reported with standardized questionnaire in late adulthood.

RESULTS

In comparison to the most common haplotype, one haplotype in the regulatory region of the NR3C1 was associated with increased risk of hospital admission (OR: 3.35; 95% confidence interval 1.5 to 7.3) for depressive disorders after adjusting for sex, birth year, and education. The association was statistically significant after Bonferroni correction for multiple testing. There were no other significant associations.

CONCLUSIONS

Haplotypic variation in the regulatory region of the NR3C1 may increase vulnerability to depressive disorders requiring hospital admission, but is not associated with self-reported symptoms.

Total flavonoids extracted from xiaobuxin-tang on the hyperactivity of hypothalamic-pituitary-adrenal axis in chronically stressed rats

Our previous studies have demonstrated that the total flavonoids (XBXT-2) isolated from the extract of Xiaobuxin-Tang (XBXT), a traditional Chinese herbal decoction, ameliorated behavioral alterations and hippocampal dysfunctions in chronically stressed rats. Studies over the last decades have suggested that the hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis is one of the most consistent findings in stress-related depression. Herein, we used the same chronic mild stress model of rats as before to further investigate the effect of XBXT-2 on the hyperactivity of HPA axis, including the stress hormones levels and glucocorticoid receptors (GRs) expression. Our ELISA results showed that chronic administration of XBXT-2 (25, 50 mg kg⁻¹, p.o., 28 days, the effective doses for behavioral responses) significantly decreased serum corticosterone level and its upstream stress hormone adrenocorticotropic hormone (ACTH) level in chronically stressed rats. Furthermore, western blotting result demonstrated XBXT-2 treatment ameliorated stress-induced decrease of GRs expression in hippocampus, an important target involved in the hyperactivity of HPA axis. These results were similar to that of classic antidepressant imipramine treatment (10 mg kg⁻¹, p.o.). In conclusion, the modulation of HPA axis produced by XBXT-2, including the inhibition of stress hormones levels and up-regulation of hippocampal GRs expression, may be an important mechanism underlying its antidepressant-like effect in chronically stressed rats.

Electroconvulsive therapy has acute immunological and neuroendocrine effects in patients with major depressive disorder

BACKGROUND

Major depressive disorder is associated with alterations in the neuroendocrine as well as immune system. Few studies examined the impact of electroconvulsive therapy (ECT) on these systems in patients with major depressive disorder (MDD).

METHODS

In this explorative study 12 patients suffering from medication-resistant MDD or MDD with psychotic features were studied during the first, the fifth and eleventh session of ECT. Blood samples were taken immediately prior to the electrostimulus and 5, 15 and 30 min after the electrostimulus to assess various lipopolysaccharide (LPS) stimulated or T-cell mitogen induced cytokines, immune cell numbers, Natural Killer cell activity, cortisol and ACTH.

RESULTS

Acute ECT increased the LPS-stimulated production of the cytokines IL-6 and TNF-α by peripheral monocytes but not the production of the anti-inflammatory cytokine IL-10. Acute ECT decreased T cell mitogen-induced levels of IFN-γ but IL-10 and IL-4 levels were left unaffected while NK cell activity increased momentarily but significantly. Cortisol and ACTH rose significantly after electrostimulus. Repeated ECT had no significant effect on any of the parameters.

LIMITATIONS

The study had a small group size. Also the patient group was heterogeneous as it consisted of patients with therapy-resistant depression with or without psychotic features.

CONCLUSIONS

Results suggest that acute ECT is associated with transient immunological and neuro-endocrine changes, while repeated ECT does not have an additive effect on the immune and neuroendocrine functions.

Glucocorticoids, cytokines and brain abnormalities in depression

Major depression (MD) is a common psychiatric disorder with a complex and multifactor aetiology. Potential mechanisms associated with the pathogenesis of this disorder include monoamine deficits, hypothalamic-pituitary-adrenal (HPA) axis dysfunctions, inflammatory and/or neurodegenerative alterations. An increased secretion and reactivity of cortisol together with an altered feedback inhibition are the most widely observed HPA abnormalities in MD patients. Glucocorticoids, such as cortisol, are vital hormones that are released in response to stress, and regulate metabolism and immunity but also neuronal survival and neurogenesis. Interestingly depression is highly prevalent in infectious, autoimmune and neurodegenerative diseases and at the same time, depressed patients show higher levels of pro-inflammatory cytokines. Since communication occurs between the endocrine, immune and central nervous system, an activation of the inflammatory responses can affect neuroendocrine processes, and vice versa. Therefore, HPA axis hyperactivity and inflammation might be part of the same pathophysiological process: HPA axis hyperactivity is a marker of glucocorticoid resistance, implying ineffective action of glucocorticoid hormones on target tissues, which could lead to immune activation; and, equally, inflammation could stimulate HPA axis activity via both a direct action of cytokines on the brain and by inducing glucocorticoid resistance. In addition, increased levels of pro-inflammatory cytokines also induce the production of neurotoxic end products of the tryptophan-kynurenine pathway. Although the evidence for neurodegeneration in MD is controversial, depression is co-morbid with many other conditions where neurodegeneration is present. Since several systems seem to be involved interacting with each other, we cannot unequivocally accept the simple model that glucocorticoids induce neurodegeneration, but rather that elevated cytokines, in the context of glucocorticoid resistance, are probably the offenders. Chronic inflammatory changes in the presence of glucocorticoid resistance may represent a common feature that could be responsible for the enhanced vulnerability of depressed patients to develop neurodegenerative changes later in life. However, further studies are needed to clarify the relative contribution of glucocorticoids and inflammatory signals to MD and other disorders.

Cognitive function, dementia and type 2 diabetes mellitus in the elderly

Increasing numbers of people are developing type 2 diabetes mellitus, but interventions to prevent and treat the classic microvascular and macrovascular complications have improved, so that people are living longer with the condition. This trend means that novel complications of type 2 diabetes mellitus, which are not targeted by current management strategies, could start to emerge. Cognitive impairment and dementia could come into this category. Type 2 diabetes mellitus is associated with a 1.5-2.5-fold increased risk of dementia. The etiology of dementia and cognitive impairment in people with type 2 diabetes mellitus is probably multifactorial. Chronic hyperglycemia is implicated, perhaps by promoting the development of cerebral microvascular disease. Data suggest that the brains of older people with type 2 diabetes mellitus might be vulnerable to the effects of recurrent, severe hypoglycemia. Other possible moderators of cognitive function include inflammatory mediators, rheological factors and dysregulation of the hypothalamic-pituitary-adrenal axis. Cognitive function should now be included as a standard end point in randomized trials of therapeutic interventions in patients with type 2 diabetes mellitus.

Volume of the adrenal and pituitary glands in depression

Numerous studies have shown that the hypothalamic-pituitary-adrenal (HPA) axis is hyperactive in some depressed patients. It is unclear whether such hyperactivity results in changed volumes of the adrenal glands, pituitary gland and hypothalamus. We systematically reviewed all controlled studies on the adrenal or pituitary glands or hypothalamus volume in unipolar depressive disorder published in PubMed 1966 to December 2009. We identified three studies that investigated the volume of the adrenal glands and eight studies that examined the volume of the pituitary gland, but no studies on hypothalamus were found. Two out of three studies found a statistically significant increase in adrenal volume in patients compared to controls. Four out of eight studies found a statistically significant increase in pituitary volume in patients compared to controls. Different methodological problems were identified such as small population samples, different subtypes of depression and insufficient matching of patients and controls. Due to large heterogeneity of study designs and data, it was futile to make a meta-analysis. It is concluded that it remains unclear whether hyperactivity of the HPA axis results in enlarged adrenal and pituitary glands and it is suggested that prospective studies should be conducted with scanning during successive depressive episodes and periods of remission.

Contribution of diet and major depression to incidence of acute myocardial infarction (AMI)

BACKGROUND

Despite significant improvements in the treatment of coronary heart disease (CHD), it is still a major cause of mortality and morbidity among the Iranian population. Epidemiological studies have documented that risk factors including smoking and the biochemical profile are responsible for the development of acute myocardial infarction (AMI). Psychological factors have been discussed as potential risk factors for coronary heart disease. Among emotional factors, depression correlates with coronary heart disease, particularly myocardial infarction.

METHODS

This case-control study was conducted on 120 cases (69 males and 51 females) of acute myocardial infarction (AMI) and 120 controls, with a mean age of 62.48 ± 15.39 years. Cases and controls were matched by age, residence and sex.

RESULTS

The results revealed that severe depression was independently associated with the risk of AMI (P = 0.025, OR = 2.6, 95% CI 1.1-5.8). The analysis of variables indicated that risk factors for developing depression were unmarried, low levels of polyunsaturated fatty acids (PUFAs), total dietary fiber (TDF) and carbohydrates. The levels of these dietary factors were lowest in severely depressed patients compared to those categorised as moderate or mild cases. Furthermore, severely depressed subjects were associated with higher levels of total cholesterol, high systolic blood pressure (SBP) and WHR. Age, income, a family history of coronary heart disease, education level, sex, employment and smoking were not associated with severe depression.

CONCLUSION

The present study demonstrated that severe depression symptoms are independent risk factors for AMI. Furthermore, severe depression was associated with an unhealthy diet and AMI risk factors.