Evidence for physiological effects of hypercortisolemia in psychiatric patients

MAD2B Blunts Chronic Unpredictable Stress and Corticosterone Stimulation-Induced Depression-Like Behaviors in Mice

BACKGROUND

Depression is a prevalent and recurrent psychiatric disorder. Aberrant neural structure and activity play fundamental roles in the occurrence of depression. Mitotic arrest deficient protein (MAD2B) is highly expressed in neurons and may be implicated in synaptic plasticity in the central nervous system. However, the effect of MAD2B in depression, as well as the related molecular mechanism, is uncertain.

METHODS

Here, we employed mouse models of depression induced by chronic unpredictable stress exposure or corticosterone (CORT) stimulation. Depression-like behaviors in mice were evaluated by sucrose preference, forced swimming, and tail suspension tests. Hippocampal MAD2B overexpression was mediated by adeno-associated virus 8 containing enhanced green fluorescent protein. In vitro primary neuronal cells were obtained from the hippocampus of rat embryos and were treated with CORT, and MAD2B overexpression was performed using lentivirus. MAD2B and glutamate metabotropic receptor 4 (GRM4) levels were evaluated by western blots and quantitative PCR. Primary neuronal miR-29b-3p expression was detected by quantitative PCR.

RESULTS

MAD2B expression was reduced in the hippocampus in mice exhibiting depressive-like behaviors. However, hippocampal MAD2B overexpression protected mice from developing either chronic unpredictable stress- or CORT-induced depression-like behaviors, an effect associated with reduced expression of GRM4, a presynaptic receptor involved in depression. Moreover, MAD2B overexpression in primary neuronal cells also decreased GRM4 expression while enhancing the level of miR-29b-3p; this phenomenon was also observed under CORT stimulation.

CONCLUSIONS

Our results suggest an important role of neuronal MAD2B in the pathogenesis of depression via the miR-29b-3p/GRM4 signaling pathway. MAD2B could be a potential therapeutic target for depressive disorders.

Depressive and Neurocognitive Disorders in the Context of the Inflammatory Background of COVID-19

The dysfunctional effects of the coronavirus disease 2019 (COVID-19) infection on the nervous system are established. The manifestation of neuropsychiatric symptoms during and after infection is influenced by the neuroinvasive and neurotrophic properties of SARS-CoV-2 as well as strong inflammation characterised by a specific "cytokine storm". Research suggests that a strong immune response to a SARS-CoV-2 infection and psychological stressors related to the pandemic may cause chronic inflammatory processes in the body with elevated levels of inflammatory markers contributing to the intensification of neurodegenerative processes. It is suggested that neuroinflammation and associated central nervous system changes may significantly contribute to the etiopathogenesis of depressive disorders. In addition, symptoms after a COVID-19 infection may persist for up to several weeks after an acute infection as a post-COVID-19 syndrome. Moreover, previous knowledge indicates that among SSRI (selective serotonin reuptake inhibitor) group antidepressants, fluoxetine is a promising drug against COVID-19. In conclusion, further research, observation and broadening of the knowledge of the pathomechanism of a SARS-CoV-2 infection and the impact on potential complications are necessary. It is essential to continue research in order to assess the long-term neuropsychiatric effects in COVID-19 patients and to find new therapeutic strategies.

Morphine Exposure and Enhanced Depression-like Behaviour Confronting Chronic Stress in Adult Male Offspring Rat

Introduction:

Opioid addiction is an important concern in the World. Reports demonstrate that substance use disorder could influence genetic and environmental factors, and children of addicts have a higher rate of psychopathology. In this study, we investigated depression-like behavior among offspring of morphine-exposed rat parents.

Methods:

Adult male and female Wistar rats received morphine for 21 consecutive days and then let them were free of drugs for ten days. Offspring of these rats were divided into three distinct groups: maternal morphine-exposed, paternal morphine-exposed, and both maternal and paternal morphine-exposed. We used sucrose preference and Forced Swim Test (FST) to measure depression-like behavior. Also, we induced chronic mild stress using repeated corticosterone injection and evaluated depression-like behavior in offspring of morphine-exposed parents compared with offspring of healthy ones.

Results:

Results indicated that depression-like behaviors in the offspring of morphine-exposed rats were higher than those in the offspring of the control group in confronting with chronic mild stress. Additionally, mild chronic stress can produce an exaggerated effect on depression-like behavior in offspring of the morphine-exposed parent(s) compared with those of the control group.

Conclusion:

Our data support the previous hypothesis that the depression rate is higher in the children of addicts. We verified that even when mother or father was clean of opioid in the time of gestation, their children would be susceptible to depression. Dysregulation of hypothalamic-pituitary-adrenal axis and changing in neuronal features in the hippocampus increased depression-like behavior in the offspring of morphine-exposure parents.

Of sound mind and body: depression, disease, and accelerated aging

Major depressive disorder (MDD) is associated with a high rate of developing serious medical comorbidities such as cardiovascular disease, stroke, dementia, osteoporosis, diabetes, and the metabolic syndrome. These are conditions that typically occur late in life, and it has been suggested that MDD may be associated with “accelerated aging.” We review several moderators and mediators that may accompany MDD and that may give rise to these comorbid medical conditions. We first review the moderating effects of psychological styles of coping, genetic predisposition, and epigenetic modifications (eg, secondary to childhood adversity). We then focus on several interlinked mediators occurring in MDD (or at least in subtypes of MDD) that may contribute to the medical comorbidity burden and to accelerated aging: limbic-hypothalamic-pituitary-adrenal axis alterations, diminution in glucocorticoid receptor function, altered glucose tolerance and insulin sensitivity, excitotoxicity, increases in intracellular calcium, oxidative stress, a proinflammatory milieu, lowered levels of “counter-regulatory” neurosteroids (such as allopregnanolone and dehydroepiandrosterone), diminished neurotrophic activity, and accelerated cell aging, manifest as alterations in telomerase activity and as shortening of telomeres, which can lead to apoptosis and cell death. In this model, MDD is characterized by a surfeit of potentially destructive mediators and an insufficiency of protective or restorative ones. These factors interact in increasing the likelihood of physical disease and of accelerated aging at the cellular level. We conclude with suggestions for novel mechanism-based therapeutics based on these mediators.

Chronic corticosterone administration down-regulates metabotropic glutamate receptor 5 protein expression in the rat hippocampus

Several lines of evidence suggest a dysfunctional glutamate system in major depressive disorder (MDD). Recently, we reported reduced levels of metabotropic glutamate receptor subtype 5 (mGluR5) in postmortem brains in MDD, however the neurobiological mechanisms that induce these abnormalities are unclear. In the present study, we examined the effect of chronic corticosterone (CORT) administration on the expression of mGluR5 protein and mRNA in the rat frontal cortex and hippocampus. Rats were injected with CORT (40 mg/kg s.c.) or vehicled once daily for 21 days. The expression of mGluR5 protein and mRNA was assessed by Western blotting and quantitative real-time PCR (qPCR). In addition, mGluR1 protein was measured in the same animals. The results revealed that while there was a significant reduction (-27%, P=0.0006) in mGluR5 protein expression in the hippocampus from CORT treated rats, mRNA levels were unchanged. Also unchanged were mGluR5 mRNA and protein levels in the frontal cortex and mGluR1 protein levels in both brain regions. Our findings provide the first evidence that chronic CORT exposure regulates the expression of mGluR5 and are in line with previous postmortem and imaging studies showing reduced mGluR5 in MDD. Our findings suggest that elevated levels of glucocorticoids may contribute to impairments in glutamate neurotransmission in MDD.

Glucocorticoids. Mood, memory, and mechanisms

Elevated circulating levels of glucocorticoids are associated with psychiatric symptoms across several different conditions. It remains unknown if this hormonal abnormality is a cause or an effect of the psychiatric conditions. For example, the hypercortisolemia observed in a subset of patients with depression may have a direct impact on the symptoms of depression, but it is also possible that the hypercortisolemia merely reflects the stress associated with depression. Further, rather than causing depression, hypercortisolemia could represent a homeostatic attempt to overcome glucocorticoid resistance. Each of these possibilities will be considered, and correlational and causal evidence will be reviewed. This article will focus on the relationships between glucocorticoids and psychiatric symptoms in Cushing's syndrome, major depression, and steroid psychosis/steroid dementia, as well as the effects of exogenously administered glucocorticoids in normal volunteers. Similarities and differences in the relationship of glucocorticoid hormones to psychiatric symptoms in these conditions will be reviewed. Possible mediators of glucocorticoid effects on the brain and behavior, as well as possible "pro-aging" effects of glucocorticoids in certain cells of the body, will be reviewed. The article concludes with a conceptual model of glucocorticoid actions in the brain that may lead to novel therapeutic opportunities.

Antidepressant-like effects of the glucocorticoid receptor antagonist RU-43044 are associated with changes in prefrontal dopamine in mouse models of depression

Chronic corticosterone and isolation rearing paradigms may provide reliable mouse models of depression. Using these models, the present study examined if the specific glucocorticoid receptor antagonist, RU-43044, has an antidepressant-like effect, and studied the possible role of prefrontal neurotransmission on the behavioral effects. Chronic administration of corticosterone and isolation rearing increased the immobility time in the forced swim and tail suspension tests. Subchronic treatment with RU-43044 decreased the immobility time in the forced swim test in chronic corticosterone-treated and isolation-reared mice, but not the control mice. Chronic corticosterone decreased the levels of cortical glucocorticoid receptors and stress-induced increases in plasma corticosterone levels, and blocked the response of plasma corticosterone to dexamethasone, while isolation rearing did not cause any changes in the glucocorticoid receptor system. Both chronic corticosterone and isolation rearing markedly increased high K+ -induced dopamine release, but not serotonin release, in the prefrontal cortex. Subchronic RU-43044 reversed the enhanced release of dopamine in the prefrontal cortex of chronic corticosterone-treated and isolation-reared mice. These results suggest that chronic corticosterone and isolation rearing increase the depressive-like behavior in glucocorticoid receptor-dependent and independent manners, respectively, and that RU-43044 shows an antidepressant-like effect, probably via an inhibition of enhanced prefrontal dopaminergic neurotransmission in these mouse models.

A mouse model of depression induced by repeated corticosterone injections

A rat model of depression has been recently developed by exogenous corticosterone administration. In this study, we further determined whether corticosterone administration also increased depression-like behavior in mice and explored the brain biochemical consequences of exposure to this administration paradigm. Mice received repeated injections of vehicle and 20 mg/kg of corticosterone for 1, 3 and 5 weeks, and then were subjected to the forced-swim and tail suspension tests. The results showed that repeated corticosterone injections increased immobility behavior in the forced-swim and tail suspension tests in a time-dependent manner. Meanwhile, this injection paradigm produced a time-related effect on tyrosine hydroxylase (TH) levels in the hippocampus of mice. These results are consistent with correlations in stress-induced depression models, and suggest that the repeated corticosterone injection paradigm provides a useful and reliable mouse model within which to further study the role of stress and glucocorticoids in depressive illness, as well as screen for antidepressants or preventive drugs.

Effect of different doses of corticosterone on depression-like behavior and HPA axis responses to a novel stressor

Stress is recognized to precipitate depressive illness, yet the specific relationship between stress, glucocorticoids and depression is not well understood. We have recently shown that repeated corticosterone (CORT) injections reliably increase depression-like behavior on the forced-swim test in rats, suggesting that glucocorticoids can precipitate depressive symptomatology. The purpose of this experiment was to determine the extent to which the effects of CORT on depression-like behavior depend on (1) the dose-injected and (2) the duration of treatment. Rats received either acute or repeated injections of vehicle, 10, 20 or 40 mg/kg of CORT, and then were subjected to the forced-swim test. Serum CORT levels were assessed after the 21-day injection period, and 30 and 60 min after the onset of forced-swim testing. Repeated, but not acute, CORT injections decreased body weight and increased immobility behavior in the forced-swim test in a dose-dependent manner. In addition, all doses of repeated CORT injections suppressed CORT release after the novel stress of forced-swim testing. Our results demonstrate that glucocorticoids increase depression-like behavior in rats in a dose-dependent manner and disrupt normal HPA axis function. These results support the hypothesis that high levels of cortisol contribute to the etiology of depressive symptomatology in humans.

Association of depression with medical illness: does cortisol play a role?

Elevated cortisol in a subset of depressed patients is an enduring and well-replicated finding. Much interest has focused on the possible effects of depression on the hippocampus; however, an emerging body of evidence suggests an association between depression and non-central nervous system illnesses. In this review, data on the effects of depression on the brain and other organ systems sensitive to elevated cortisol are discussed. From searches of the MEDLINE, PSYCHINFO, and Current Contents databases, and other sources, articles were found specifically related to depression and physical changes or medical conditions associated with corticosteroid excess in patients with Cushing's disease, including cognitive impairment, hippocampal atrophy, increased waist-to-hip ratio, bone loss, hypertension, diabetes, peptic ulcers, and hyperlipidemia. Data are strongest for a relationship between elevated cortisol and depression, hippocampal atrophy, cognitive impairment, abdominal obesity, and loss of bone density. Some evidence suggests an association between depression and hypertension, peptic ulcers, and diabetes. Depression does not appear to be associated with hyperlipidemia. The data provide some support for similar health effects in depressed patients and patients with Cushing's disease or the metabolic syndrome; however, additional studies are needed relating systemic effects of depression to cortisol. Limitations of the current literature, treatment implications, and possible directions for future research are discussed.

Cushing’s disease and melancholia

Striking similarities exist in the endocrinology of Cushing's disease and melancholic depression.Laboratory abnormalities, which have been found in both, include raised urinary,plasma and salivary cortisol, non-suppression of cortisol in the dexamethasone suppression test and adrenocorticotrophin (ACTH) hypersecretion. The hypercortisolism can be so severe in melancholic depression that it is difficult to distinguish from Cushing's disease and has been described as a "pseudo-Cushing's" state. Cerebrospinal fluid corticotrophin-releasing hormone (CRH) levels have been found to be lower in patients with Cushing's disease than in depressed subjects. Dynamic endocrine tests may help to distinguish between the two disorders.An exaggerated response to synacthen has been found in both but a reduced ACTH response to CRH occurs in depression, unlike those with Cushing's disease who show ACTH hyper-responsiveness. Other tests, which may help to distinguish between the two disorders,include the dexamethasone-CRH test, the naloxone test, the insulin-induced hypoglycemia test and the desmopressin stimulation test. Similarities in psychiatric symptoms have been recognised for many years. More recently, the physical complications of melancholic depression have been noted. These include osteoporosis, an increased risk of death from cardiovascular disease, hypertension, a redistribution of fat to intra abdominal sites and insulin resistance. Cushing's disease shares these physical complications and we propose that the common underlying factor is excessive plasma glucocorticoids. The increasing recognition of the physical complications and the increased morbidity and mortality in those who suffer from depression underscores the necessity for early detection and treatment of this illness and screening for undetected physical complications.

Plasma neopterin in major depression: relationship to basal and stimulated pituitary-adrenal cortical axis function

We measured plasma neopterin at baseline and after oCRH and ACTH(1-24) stimulation tests in 35 unmedicated, adult major-depressive patients (mean age = 41 +/- 12 years) and in 35 normal control subjects individually matched to the patients. Neopterin is released by gamma-interferon-stimulated macrophages; because gamma-interferon is secreted by activated T-lymphocytes, elevated circulating neopterin is considered to reflect activation of the cell-mediated immune system. Plasma ACTH(1-39) and cortisol also were measured as indicators of pituitary-adrenal axis activity. Baseline plasma neopterin did not differ significantly between patients and controls (medians = 6.25 and 6.57 microg/l, respectively), but the baseline neopterin:creatinine ratio showed a trend toward lower values in the patients (P < 0.07). There was no apparent plasma neopterin change from baseline (area under the curve-AUC) following oCRH or ACTH(1-24) administration in either group of subjects. As with baseline neopterin, there was no significant patient-control difference in neopterin AUC following either hormone challenge, but there were trends toward lower neopterin:creatinine ratios in the patients following both challenges. In the patients, neither baseline neopterin nor neopterin AUCs following hormone challenge were significantly correlated with age, duration of depressive episode, lifetime number of episodes, melancholic subtype, Hamilton Depression Scale total score, Hamilton factor scores, or the Hamilton suicidality item score.

Glucocorticoid receptor binding in three different cell types in major depressive disorder: lack of evidence of receptor binding defect

1. In order to further understand the apparent glucocorticoid resistance in major depressive disorder, circadian variation in cortisol concentration, dexamethasone suppression and glucocorticoid receptor binding in mononuclear leukocytes, polymorphonuclear leukocytes and cultured skin fibroblasts were measured in rigidly defined major depressive disorder patients and non-depressed psychiatric controls. 2. Mononuclear leukocytes binding to glucocorticoid correlated significantly with polymorphonuclear leukocytes binding to glucocorticoid, but both determinations failed to differentiate major depressive disorder and control subjects. 3. Initial and post-dexamethasone in vitro fibroblast binding to glucocorticoid was not different between major depressive disorder and non-depressed control subjects. 4. The phenomenon of glucocorticoid resistance in major depressive disorder remains unexplained.

Measurement of cortisol and lymphocyte subpopulations in depressed and conduct-disordered adolescents

Lymphocyte subpopulations were analyzed in 11 adolescents with major depressive disorder, 11 with conduct disorder, and eight normal age-matched subjects. No significant differences were noted on any T or B cell measure between the groups. Further, no significant correlations were found between any cortisol measure (baseline cortisol, post-dexamethasone cortisol, urinary free cortisol) and any lymphocyte measure in either depressed or conduct-disordered adolescents. The negative findings in this small sample contrast with those reported in adult patients and suggest that an aging effect may be associated with the immunological changes reported in older depressed patients.

Lymphocyte subpopulations in depressed elderly women

Dexamethasone Suppression Tests (DST) and measurement of lymphocyte subpopulations were conducted in 21 medically healthy elderly women with major depressive disorder and 77 healthy elderly women volunteers. Depressed women revealed significantly reduced absolute lymphocytes (p less than 0.01), T cells (p less than 0.01), and T helper cells (p less than 0.02) compared to normal elderly women. Of the depressed women, 50% had positive DSTs (postdexamethasone cortisols greater than 5 micrograms/dl) compared to 5.4% of the normal women (p less than 0.0001). Within the depressed group, patients with positive DSTs had significantly reduced absolute lymphocytes (p less than 0.05) and T helper cells (p less than 0.025) compared with depressed women who had normal DSTs. Further, a significant negative correlation was found between postdexamethasone cortisols (at both 4:00 and 11:00 PM) and absolute lymphocyte count and T helper cells. These data suggest that the hypercortisolemia seen in some patients with major depressive disorder is sufficient to alter leukocyte distribution in the peripheral circulation, particularly that of the T helper cell subset. The association between cortisol and lymphopenia appears to be more pronounced in an elderly population than in younger depressed patients.

Cardiovascular risk factors in affective disorder

100 patients with affective disorder (unipolar affective disorder and bipolar affective disorder) were evaluated for evidence of increased risk for the major cardiovascular risk factors including hypertension, hypercholesterolemia, obesity, and cigarette use. Unipolar affective disorder patients showed no evidence of increased cardiovascular risk compared to population controls. Bipolar affective disorder patients displayed increased systolic blood pressure, definite hypertension, and use of cigarettes. These findings are consistent with a link between affective disorders and excess cardiovascular mortality.

Cushing's syndrome after treatment: changes in cortisol and ACTH levels, and amelioration of the depressive syndrome

Twenty-three patients with pituitary adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome were studied before and after treatment. The relationship between the amelioration of the depressive syndrome and changes in cortisol and ACTH levels was investigated. There was a significant difference in mean change in 24-hour urinary free cortisol (UFC) excretion for changes in the depressed mood score from first to last visit. There were also significant correlations between decreases in UFC and decreases in both the depressed mood score and the modified Hamilton depression score. These relationships were not found for ACTH. Furthermore, with cortisol decreased to normal levels, continued high ACTH levels did not prevent improvement in depressed mood. The possibility that cortisol may also play a role in the pathogenesis and/or maintenance of the mood disorder in psychiatric patients is discussed.