Glucocorticoid Receptor Density Research Articles

Разработка и реализация протокола поведенческого эксперимента для оценки когнитивных способностей и социального поведения мышей после стресса в раннем возрасте

<p style="text-align: justify;">This manuscript presents a protocol designed for the comprehensive investigation of early life stress (ELS) outcomes and a feasibility study conducted with this protocol. ELS alters normal development by interfering at various levels: hormonal changes, brain cellular architecture, epigenome, and chromosomal structural elements. The protocol combines classic behavioral tests with advanced molecular techniques to obtain comprehensive data and thus uncover the underlying mechanisms of ELS. In this protocol, the main source of stress is maternal separation. Briefly, a group of C57Bl/6 mice undergoes maternal separation; then, mice perform the radial maze test and the resident-intruder test. As a control, another group of mice stays undisturbed and performs the same behavioral tests in the same timeframe. After the behavioral tests, biosamples are collected, including urine for corticosterone measurements, peripheral blood, hippocampus, amygdala, and prefrontal cortex tissues for DNA isolation and its downstream analyses (DNA methylation profiling and telomere length measuring), and whole brains for immunohistochemistry analysis of the glucocorticoid receptor density. This protocol was successfully tested as a feasibility study for a large-scale investigation that addresses potential flaws to establish a robust methodology. This paper reports on a comprehensive approach to examining multiple aspects of development that interrogates a holistic analysis of multilayer and multidimensional data and may contribute valuable insights for both animal and human studies.</p>

Rapid Changes in the Expression of Active Caspase-3 and Glucocorticoid Receptors in Striatum Cells Induced by Neuroinflammation

Activation of microglia, resident immune cells of the central nervous system, plays a key role in the pathogenesis of neurological disorders induced by infections, as well as traumatic and ischemic events. Understanding the responses of brain cells, primarily microglial cells, to damaging effects can help overcome their pathological consequences. In this work, we analyzed the cellular effects of bacterial lipopolysaccharide (LPS), which is widely used as a pro-inflammatory stimulus. The injection of LPS into the area of right striatum of rats caused a pronounced neurological deficit in a day, which was accompanied by an increase in the number of microglial cells, an increase in the density of glucocorticoid receptors (GR) and their translocation into the nuclei of cells co-expressing the executive protease of apoptosis, active caspase-3 and GR, in the area of LPS injection. The results indicate acute changes in the activity of microglial cells, as well as in the expression and functional activity of GR in response to bacterial endotoxin. Further elucidation of the functional role of active caspase-3 and GR in microglial cells under conditions of pro-inflammatory activation may help identify targets for alleviating the symptoms of a neurological disorder.

Gestational stress and perinatal SSRIs differentially impact the maternal and neonatal microbiome-gut-brain axis.

Selective serotonin reuptake inhibitors (SSRIs) are the most popular antidepressant medications used to manage perinatal mood disturbances, yet our understanding of how they affect the microbiome-gut-brain axis of the mother and offspring is limited. The purpose of this study was to determine how peripartum SSRI treatment may prevent the effects of gestational stress on plasticity in the maternal hippocampus, plasticity in the neonatal brain and related changes in gut microbiota. To do this Sprague-Dawley female rats were left untreated or subjected to unpredictable stress during pregnancy. Half of the females were supplemented daily with fluoxetine. On postpartum day 2 brains were collected for measurement of plasticity (neurogenesis and microglia content) in the maternal hippocampus and in the neonatal brain. Glucocorticoid receptor density was also investigated in the maternal hippocampus. Microbiota composition was analyzed in fecal samples of dams during and after pregnancy, and colon tissue samples from offspring on postnatal day 2. Main findings show there are significant changes to the maternal microbiome-gut-brain axis that may be fundamental to mediating plasticity in the maternal hippocampus. In addition, there is significant impact of gestational stress on neonatal gut microbiota and brain microglia density, while the effects of SSRIs are limited. This is the first study to explore the impact of gestational stress and SSRIs on the microbiome-gut-brain axis in the mother and neonate. Findings from this study will help inform pathways to intervention strategies including stress reduction techniques and/or microbiota targeted nutritional approaches directed towards improving maternal gut health and outcomes for mother and neonate.

The effects of synthetic glucocorticoid treatment for inflammatory disease on brain structure, function, and dementia outcomes: A systematic review

Many regions of the brain have a high density of glucocorticoid receptors, and the prolonged elevation of endogenous glucocorticoids may cause neurotoxicity and increase risk for cognitive decline and dementia. However, despite synthetic glucocorticoids being the first line of treatment for many inflammatory diseases, few studies have addressed whether therapeutic glucocorticoids may have similar undesirable effects on the brain. Thus, our systematic review investigated the impact of long-term glucocorticoid usage on adult brain structure, cognitive function, and dementia risk. We identified 13 studies that met our eligibility criteria and found conflicting results dependent on the outcome studied. In particular, all but one study on hippocampal and amygdalar volumes found significant atrophy of both structures occurred in those who took glucocorticoids. Additionally, executive function, particularly working memory, and global cognitive function were significantly poorer in those taking long-term glucocorticoids. Notably, declines in episodic memory were not associated with long-term usage. Furthermore, most studies of dementia (all-cause) and Alzheimer’s disease, excluding vascular dementia, showed null to negative associations with glucocorticoids, suggesting a potential protective effect. Therefore, glucocorticoid therapy in those with inflammatory disease may impair certain brain structures and specific cognitive functions, but could lead to a significantly reduced risk of dementia.

Long-term consequences of alcohol use in early adolescent mice: Focus on neuroadaptations in GR, CRF and BDNF.

Our aim was to assess the cognitive and emotional state, as well as related-changes in the glucocorticoid receptor (GR), the corticotropin-releasing factor (CRF) and the brain-derived neurotrophic factor (BDNF) expression of adolescent C57BL/6J male mice after a 5-week two-bottle choice protocol (postnatal day [pd]21 to pd52). Additionally, we wanted to analyse whether the behavioural and neurobiological effects observed in late adolescence (pd62) lasted until adulthood (pd84). Behavioural testing revealed that alcohol during early adolescence increased anxiety-like and compulsive-related behaviours, which was maintained in adulthood. Concerning cognition, working memory was only altered in late adolescent mice, whereas object location test performance was impaired in both ages. In contrast, novel object recognition remained unaltered. Immunohistochemical analysis showed that alcohol during adolescence diminished BDNF+ cells in the cingulate cortex, the hippocampal CA1 layer and the central amygdala. Regarding hypothalamic-pituitary-adrenal axis (HPA) functioning, alcohol abuse increased the GR and CRF expression in the hypothalamic paraventricular nucleus and the central amygdala. Besides this, GR density was also higher in the prelimbic cortex and the basolateral amygdala, regardless of the animals' age. Our findings suggest that adolescent alcohol exposure led to long-term behavioural alterations, along with changes in BDNF, GR and CRF expression in limbic brain areas involved in stress response, emotional regulation and cognition.

Aberrant Early in Life Stimulation of the Stress-Response System Affects Emotional Contagion and Oxytocin Regulation in Adult Male Mice.

Results over the last decades have provided evidence suggesting that HPA axis dysfunction is a major risk factor predisposing to the development of psychopathological behaviour. This susceptibility can be programmed during developmental windows of marked neuroplasticity, allowing early-life adversity to convey vulnerability to mental illness later in life. Besides genetic predisposition, also environmental factors play a pivotal role in this process, through embodiment of the mother’s emotions, or via nutrients and hormones transferred through the placenta and the maternal milk. The aim of the current translational study was to mimic a severe stress condition by exposing female CD-1 mouse dams to abnormal levels of corticosterone (80 µg/mL) in the drinking water either during the last week of pregnancy (PreCORT) or the first one of lactation (PostCORT), compared to an Animal Facility Rearing (AFR) control group. When tested as adults, male mice from PostCORT offspring and somewhat less the PreCORT mice exhibited a markedly increased corticosterone response to acute restraint stress, compared to perinatal AFR controls. Aberrant persistence of adolescence-typical increased interest towards novel social stimuli and somewhat deficient emotional contagion also characterised profiles in both perinatal-CORT groups. Intranasal oxytocin (0 or 20.0 µg/kg) generally managed to reduce the stress response and restore a regular behavioural phenotype. Alterations in density of glucocorticoid and mineralocorticoid receptors, oxytocin and µ- and κ-opioid receptors were found. Changes differed as a function of brain areas and the specific age window of perinatal aberrant stimulation of the HPA axis. Present results provided experimental evidence in a translational mouse model that precocious adversity represents a risk factor predisposing to the development of psychopathological behaviour.

Pharmacological Treatment of Anxiety Disorders: The Role of the HPA Axis.

Stress in general, and early life stress in particular, has been associated with the development of anxiety and mood disorders. The molecular, biological and psychological links between stress exposure and the pathogenesis of anxiety and mood disorders have been extensively studied, resulting in the search of novel psychopharmacological strategies aimed at targets of the hypothalamic-pituitary-adrenal (HPA) axis. Hyperactivity of the HPA axis has been observed in certain subgroups of patients with anxiety and mood disorders. In addition, the effects of different anti-anxiety agents on various components of the HPA axis has been investigated, including benzodiazepines, tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs). For example, benzodiazepines, including clonazepam and alprazolam, have been demonstrated to reduce the activity of corticotrophin releasing factor (CRF) neurons in the hypothalamus. TCAs and SSRIs are also effective anti-anxiety agents and these may act, in part, by modulating the HPA axis. In this regard, the SSRI escitalopram inhibits CRF release in the central nucleus of the amygdala, while increasing glucocorticoid receptor (GRs) density in the hippocampus and hypothalamus. The molecular effects of these anti-anxiety agents in the regulation of the HPA axis, taken together with their clinical efficacy, may provide further understanding about the role of the HPA axis in the pathophysiology of mood and anxiety disorders, paving the way for the development of novel therapeutic strategies.

Особенности свободнорадикального окисления и динамики содержания кортикостероидных рецепторов в легких у животных с разной чувствительностью к гипоксии в постреанимационном периоде

Цель исследования - изучение особенностей динамики показателей свободнорадикального окисления и уровня кортикостероидных рецепторов в легких у животных с разной чувствительностью к гипоксии в постреанимационном периоде. Методика. Эксперимент выполнен на самцах беспородных белых крыс, разделенных по устойчивости к гипоксии на 2 группы: неустойчивые и высокоустойчивые. Остановку системного кровообращения продолжительностью 5 мин моделировали под общим эфирным наркозом (через 1 нед после тестирования на устойчивость к гипоксии) интраторакальным пережатием сосудистого пучка сердца с последующей реанимацией. Через 1, 3, 5, 7, 14, 21 и 35 сут животных под эфирным наркозом декапитировали. В плазме крови определяли содержание кортикостерона и альдостерона, в гомогенатах легких - концентрацию глюкокортикоидных и минералокортикоидных рецепторов, уровни продуктов, реагирующих с тиобарбитуровой кислотой, карбонилированных белков, железозависимое образование битирозина, активность супероксиддисмутазы, каталазы, содержание восстановленного глутатиона. Результаты. Установлено, что для неустойчивых к гипоксии животных характерна высокая интенсивность свободнорадикального окисления, проявляющаяся развитием карбонильного стресса на фоне снижения активности ключевых антиоксидантов и сопряженная с выраженными изменениями динамики кортикостероидных рецепторов: в первые 3 сут постреанимационного периода наблюдалось снижение уровня кортикостероидных рецепторов, а к концу 35-суточного мониторинга значительное нарастание концентрации минералокортикоидных рецепторов. Высокую степень устойчивости к гипоксии отличает относительно низкая интенсивность свободнорадикального окисления, характеризующаяся только усилением липопероксидации за счет адекватной емкости и сохранности водорастворимых антиоксидантных систем, экранирующих белки. В раннем восстановительном периоде это сопровождается сохранением уровня кортикостероидных рецепторов, в позднем - существенным ростом концентрации глюкокортикоидных рецепторов. Заключение. Увеличение содержания глюкокортикоидных рецепторов у высокоустойчивых к гипоксии животных в позднем восстановительном периоде (14-е - 35-е сут) играет важную роль, предположительно путем модулирования течения воспалительного процесса, ограничения неконтролируемых иммунных реакции и повреждение тканей. Следствием значительного нарастания концентрации минералокортикоидных рецепторов у животных с низкой устойчивостью к гипоксии может быть усиление сосудистого ремоделирования и развитие фиброза в легких. Aim. The aim of the study was to characterize changes in free radical oxidation and corticosteroid receptor density in the lungs of animals with different sensitivity to hypoxia in the postresuscitation period. Methods. Experiments were performed on mongrel male white rats divided into two groups based on their hypoxia resistance, non-resistant and highly resistant. One week after testing the rats for resistance to hypoxia, a 5-min arrest of systemic circulation was modeled under ether anesthesia by intrathoracic compression of the vascular bundle of the heart with subsequent resuscitation. The follow-up period was 35 days. At 1, 3, 5, 7, 14, 21, and 35 days, the animals were sacrificed by decapitation under ether anesthesia, and blood and tissue samples were collected. Concentrations of corticosterone and aldosterone were measured in plasma; concentrations of glucocorticoid and mineralocorticoid receptors, thiobarbituric acid reactive substances, and carbonylated proteins, iron-dependent formation of dityrosine, activities of superoxide dismutase and catalase, and concentration of reduced glutathione were measured in lung homogenates. Results. Hypoxia non-resistant rats had a high intensity of free radical oxidation as evident from the development of carbonyl stress associated with decreased activities of key antioxidants and pronounced changes in the dynamics of corticosteroid receptors. A reduced level of corticosteroid receptors was observed in the first three days of resuscitation period and followed by a significant increase in mineralocorticoid receptors at the end of 35-day monitoring. High resistance to hypoxia was characterized by a relatively low intensity of free radical oxidation, evident only from increased lipid peroxidation, due to an adequate capacity and preservation of water-soluble antioxidants. During the early recovery period, high resistance to hypoxia was associated with preserved level of corticosteroid receptors whereas during late recovery, the high hypoxia resistance was associated with a significant increase in the concentration of glucocorticoid receptors. Conclusion. The increased density of glucocorticoid receptors in hypoxia high-resistant animals during the late recovery period (days 14-35) plays an important role, presumably by modulating the inflammatory process and restricting uncontrolled immune responses and tissue damage. The significant increase in mineralocorticoid receptors in hypoxia low-resistance animals may result in stimulation of vascular remodeling and development of pulmonary fibrosis.

GR Dimerization and the Impact of GR Dimerization on GR Protein Stability and Half-Life.

Pharmacologically, glucocorticoids, which mediate their effects via the glucocorticoid receptor (GR), are a most effective therapy for inflammatory diseases despite the fact that chronic use causes side-effects and acquired GC resistance. The design of drugs with fewer side-effects and less potential for the development of resistance is therefore considered crucial for improved therapy. Dimerization of the GR is an integral step in glucocorticoid signaling and has been identified as a possible molecular site to target for drug development of anti-inflammatory drugs with an improved therapeutic index. Most of the current understanding regarding the role of GR dimerization in GC signaling derives for dimerization deficient mutants, although the role of ligands biased toward monomerization has also been described. Even though designing for loss of dimerization has mostly been applied for reduction of side-effect profile, designing for loss of dimerization may also be a fruitful strategy for the development of GC drugs with less potential to develop GC resistance. GC-induced resistance affects up to 30% of users and is due to a reduction in the GR functional pool. Several molecular mechanisms of GC-mediated reductions in GR pool have been described, one of which is the autologous down-regulation of GR density by the ubiquitin-proteasome-system (UPS). Loss of GR dimerization prevents autologous down-regulation of the receptor through modulation of interactions with components of the UPS and post-translational modifications (PTMs), such as phosphorylation, which prime the GR for degradation. Rational design of conformationally biased ligands that select for a monomeric GR conformation, which increases GC sensitivity through improving GR protein stability and increasing half-life, may be a productive avenue to explore. However, potential drawbacks to this approach should be considered as well as the advantages and disadvantages in chronic vs. acute treatment regimes.

Repeated Systemic Treatment with Rapamycin Affects Behavior and Amygdala Protein Expression in Rats.

BackgroundClinical data indicate that therapy with small-molecule immunosuppressive drugs is frequently accompanied by an incidence rate of neuropsychiatric symptoms. In the current approach, we investigated in rats whether repeated administration of rapamycin, reflecting clinical conditions of patients undergoing therapy with this mammalian target of rapamycin inhibitor, precipitates changes in neurobehavioral functioning.MethodsMale adult Dark Agouti rats were daily treated with i.p. injections of rapamycin (1, 3 mg/kg) or vehicle for 8 days. On days 6 and 7, respectively, behavioral performance in the Elevated Plus-Maze and the Open-Field Test was evaluated. One day later, amygdala tissue and blood samples were taken to analyze protein expression ex vivo.ResultsThe results show that animals treated with rapamycin displayed alterations in Elevated Plus-Maze performance with more pronounced effects in the higher dose group. Besides, an increase in glucocorticoid receptor density in the amygdala was seen in both treatment groups even though p-p70 ribosomal S6 kinase alpha, a marker for mammalian target of rapamycin functioning, was not affected. Protein level of the neuronal activity marker c-Fos was again only elevated in the higher dose group. Importantly, effects occurred in the absence of acute peripheral neuroendocrine changes.ConclusionsOur findings indicate that anxiety-related behavior following rapamycin treatment was not directly attributed to mTOR-dependent mechanisms or stress but rather due to hyperexcitability of the amygdala together with glucocorticoid receptor-regulated mechanism(s) in this brain region. Together, the present results support the contention that subchronic treatment with rapamycin may induce neurobehavioral alterations in healthy, naive subjects. We here provide novel insights in central effects of systemic rapamycin in otherwise healthy subjects but also raise the question whether therapy with this drug may have detrimental effects on patients’ neuropsychological functioning during immune therapy.

Perinatal fluoxetine prevents the effect of pre-gestational maternal stress on 5-HT in the PFC, but maternal stress has enduring effects on mPFC synaptic structure in offspring

Maternal affective disorders are frequently treated with selective serotonin reuptake inhibitor medications (SSRIs); with up to 10% of women being prescribed these medications during pregnancy. Infant development depends on the early serotonergic environment, which is altered by perinatal SSRIs, raising concern about how these medications affect neural outcomes. While clinical and preclinical research suggests an impact of SSRIs on the developing brain, more research is needed to determine the effects on neuroplasticity, the serotonergic system, and the hypothalamic-pituitary-adrenal axis in neural regions mediating behavior. The current work investigated the effects of the SSRI, fluoxetine, on the serotonergic system in the prefrontal cortex (PFC) during pre-adolescence, and changes to synaptic markers and glucocorticoid receptor density in the cingulate cortex (medial PFC) of pre-adolescent and adult Sprague-Dawley male and female rats. To model aspects of Perinatal Depression and maternal anxiety, pre-gestational maternal stress was used resulting in male and female offspring from 4 groups: 1) control, 2) perinatal fluoxetine exposed, 3) pre-gestational maternal stress exposed, and 4) pre-gestational maternal stress + fluoxetine. Perinatal fluoxetine prevented the effects of maternal stress on 5-HT levels and 5-HT turnover ratio in the PFC of pre-adolescent offspring, particularly in females. However, pre-gestational stress reduced synaptophysin and PSD-95 densities in the cingulate cortex, effects that were more pronounced in males. Interestingly, perinatal fluoxetine exposure reduced GR density in adult males in this same brain area. Together, results show differential effects of perinatal SSRIs and pre-gestational maternal stress on neurodevelopment in the PFC of males and females.

Environmental Intervention as a Therapy for Adverse Programming by Ancestral Stress.

Ancestral stress can program stress sensitivity and health trajectories across multiple generations. While ancestral stress is uncontrollable to the filial generations, it is critical to identify therapies that overcome transgenerational programming. Here we report that prenatal stress in rats generates a transgenerationally heritable endocrine and epigenetic footprint and elevated stress sensitivity which can be alleviated by beneficial experiences in later life. Ancestral stress led to downregulated glucocorticoid receptor and prefrontal cortex neuronal densities along with precocious development of anxiety-like behaviours. Environmental enrichment (EE) during adolescence mitigated endocrine and neuronal markers of stress and improved miR-182 expression linked to brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) regulation in stressed lineages. Thus, EE may serve as a powerful intervention for adverse transgenerational programming through microRNA-mediated regulation of BDNF and NT-3 pathways. The identification of microRNAs that mediate the actions of EE highlights new therapeutic strategies for mental health conditions and psychiatric disease.

Hydrocortisone Counteracts Adverse Stress Effects on Dual-Task Performance by Improving Visual Sensory Processes

The impact of acute stress on executive processes is commonly attributed to glucocorticoid-induced disruptions of the pFC. However, the occipital cortex seems to express a higher density of glucocorticoid receptors. Consequently, acute stress effects on executive processes could as well be mediated by glucocorticoid (e.g., cortisol)-induced alterations of visual sensory processes. To investigate this alternative route of stress action by demarcating the effects of acute stress and cortisol on executive from those on visual sensory processes, 40 healthy young men completed a standardized stress induction (i.e., the Trier Social Stress Test) and control protocol in two consecutive sessions. In addition, they received either a placebo or hydrocortisone (0.12-mg/kg bodyweight) pill and processed a dual and a partial report task to assess their executive and visual sensory processing abilities, respectively. Hydrocortisone administration improved both partial report and dual-task performance as indicated by increased response accuracies and/or decreased RTs. Intriguingly, the hydrocortisone-induced increase in dual-task performance was completely mediated by its impact on partial report performance (i.e., visual sensory processes). Moreover, RT measures in both tasks shared approximately 26% of variance, which was only in part attributable to hydrocortisone administration (ΔR2 = 8%). By contrast, acute stress selectively impaired dual-task performance (i.e., executive processes), presumably through an alternative route of action. In summary, the present results suggest that cortisol secretion (as mimicked by hydrocortisone administration) may counteract adverse residual stress effects on executive processes by improving visual sensory processes (e.g., the maintenance and amplification of task-relevant sensory information).

Mild cognitive deficits in patients with primary adrenal insufficiency

BackgroundThe brain is a major target organ for cortisol considering its high density of glucocorticoid receptors. Several states of hypothalamus–pituitary–adrenal dysregulation point towards impairments in cognitive functioning. However, there is a very limited body of research on the effects of hypocortisolism on cognitive functioning. AimTo evaluate cognitive functioning in patients with hypocortisolism (i.e., primary adrenal insufficiency (PAI)) and to examine the possible effect of postponing early-morning hydrocortisone intake on cognitive functioning. MethodsThirty-one patients with PAI on regular morning hydrocortisone intake and 31 healthy matched controls underwent nine neuropsychological tests, evaluating memory and executive functioning. In addition, the effect of normal timing and postponement of morning hydrocortisone intake on neuropsychological tests were assessed in an additional 29 patients with PAI. ResultsCompared to controls, patients with PAI performed worse on auditory and visual memory tasks (all P≤0.024) and executive functioning tasks (all P≤0.012). In contrast, patients performed better on a concentration and an attention task (both P<0.05). Postponement of hydrocortisone intake in the morning did not affect the outcomes of neuropsychological tests. ConclusionPatients on long-term hydrocortisone replacement for PAI show mild cognitive deficits compared to controls. There was no effect of postponement of regular hydrocortisone intake on cognition.

The opposite effects of oxytocin and urocortin-3 on long-term social recognition memory, correlate with their bidirectional modulation of synaptic plasticity in the medial amygdala

Background: The brain is a major target area for cortisol considering its high density of glucocorticoid receptors. Previous studies in patients treated for hypercortisolism, such as in Cushing’s disease (CD), suggest that hypothalamic–pituitary–adrenal axis dysregulation is related to cognitive impairment. However, there is a very limited body of research on the effects of hypocortisolism on cognitive functioning. Aim: To evaluate cognitive functioning in patients with hypocortisolism (primary adrenal insufficiency (PAI)) and to examine thepossible effect of postponing early-morningHydrocortisone intake. Furthermore,we aimed to compare cognitive functioning of patients with PAI to patients with CD. Methods: Thirty-one patients with PAI and 31 healthymatched controls underwent eight neuropsychological tests, evaluating memory and executive functioning. An additional 29 patients with PAI were included who postponed their morning Hydrocortisone intake. Scores of patients in remission of CD were obtained from previous research. Results: Compared to controls, patients with PAI performed worse on auditory and visual memory tasks (all P≤0.024) and executive functioning tasks (all P≤0.012). In contrast, patients performed better on a concentration and an attention task (both P<0.05).No importantdifferenceswereobservedbetweenpatients with andwithout Hydrocortisone intake, or between patients with PAI and patients in remission of CD. Conclusion: The present study demonstrates that patients on long-term Hydrocortisone replacement for PAI show mild cognitive deficits compared to controls, and perform generally similar to patients in remission of CD. Future longitudinal studies are needed to provide more insight into the development and course of the observed cognitive alterations.

Mild cognitive deficits in patients on stable treatment for primary adrenal insufficiency

Background: The brain is a major target area for cortisol considering its high density of glucocorticoid receptors. Previous studies in patients treated for hypercortisolism, such as in Cushing’s disease (CD), suggest that hypothalamic–pituitary–adrenal axis dysregulation is related to cognitive impairment. However, there is a very limited body of research on the effects of hypocortisolism on cognitive functioning. Aim: To evaluate cognitive functioning in patients with hypocortisolism (primary adrenal insufficiency (PAI)) and to examine thepossible effect of postponing early-morningHydrocortisone intake. Furthermore,we aimed to compare cognitive functioning of patients with PAI to patients with CD. Methods: Thirty-one patients with PAI and 31 healthymatched controls underwent eight neuropsychological tests, evaluating memory and executive functioning. An additional 29 patients with PAI were included who postponed their morning Hydrocortisone intake. Scores of patients in remission of CD were obtained from previous research. Results: Compared to controls, patients with PAI performed worse on auditory and visual memory tasks (all P≤0.024) and executive functioning tasks (all P≤0.012). In contrast, patients performed better on a concentration and an attention task (both P<0.05).No importantdifferenceswereobservedbetweenpatients with andwithout Hydrocortisone intake, or between patients with PAI and patients in remission of CD. Conclusion: The present study demonstrates that patients on long-term Hydrocortisone replacement for PAI show mild cognitive deficits compared to controls, and perform generally similar to patients in remission of CD. Future longitudinal studies are needed to provide more insight into the development and course of the observed cognitive alterations.

Glucocorticoid receptor density and binding affinity in healthy horses and horses with systemic inflammatory response syndrome.

BackgroundDysregulation of the hypothalamic‐pituitary‐adrenal (HPA) axis occurs in horses with systemic inflammatory response syndrome (SIRS). Peripheral resistance to glucocorticoids has not been investigated in horses.ObjectiveTo determine if glucocorticoid receptor (GR) function in horses can be measured using flow cytometry, and to use this information to evaluate HPA axis dynamics.AnimalsEleven healthy adult horses in parts 1 and 2. Ten horses with SIRS and 10 age and sex matched controls in part 3.MethodsFlow cytometry was used to evaluate GR density and binding affinity (BA) in 3 healthy horses in part 1. In part 2, exogenous ACTH was administered to eight healthy horses. Their cortisol response and GR properties were measured. In part 3, CBC, serum biochemistry, cortisol and ACTH, and GR properties were compared between controls without SIRS (n = 10) and horses with SIRS (n = 10), and between survivors and nonsurvivors (n = 4 and n = 6 respectively).ResultsFlow cytometry can be used to measure GR properties in equine PBMCs. No correlation was observed between plasma cortisol concentration and GR density or BA in healthy horses (r = −0.145, P = .428 and r = 0.046, P = .802 respectively). Nonsurvivors with SIRS had significantly decreased GR BA (P = .008). Horses with triglyceride concentration > 28.5 mg/dL had increased odds of nonsurvival (OR=117; 95% CI, 1.94–7,060). GR BA <35.79% was associated with nonsurvival (OR = 30.33; 95% CI, 0.96–960.5).Conclusions and Clinical ImportanceTissue resistance to glucocorticoids contributes to HPA axis dysfunction in adult horses with SIRS. These horses might benefit from treatment with exogenous glucocorticoids.

Effects of stress early in gestation on hippocampal neurogenesis and glucocorticoid receptor density in pregnant rats

Pregnancy is a time of marked neural, physiological and behavioral plasticity in the female and is often a time when women are more vulnerable to stress and stress-related diseases, such as depression and anxiety. Unfortunately the impact of stress during gestation on neurobiological processes of the mother has yet to be fully determined, particularly with regard to changes in the hippocampus; a brain area that plays an important role in stress-related diseases. The present study aimed to determine how stress early in pregnancy may affect hippocampal plasticity in the pregnant female and whether these effects differ from those in virgin females. For this purpose, adult age-matched pregnant and virgin female Sprague–Dawley rats were divided into two conditions: (1) Control and (2) Stress. Females in the stress condition were restrained during days 5–11 of gestation and at matched time-points in virgin females. All pregnant females received an injection of bromodeoxyuridine (BrdU) on day 1 of gestation and were sacrificed 21days later. The same procedure was carried out at matched time points in virgin females. Results show that for number of Ki67-immunoreactive (ir) cells and doublecortin (DCX)-ir cells, there were significant interactions between reproductive state (pregnant/virgin) and stress exposure (p=.05, p=.04, respectively) with control virgin and stressed pregnant females having more Ki67-ir cells than control pregnant females and more DCX-ir cells than stressed virgin females. Results also show that pregnant females had significantly greater glucocorticoid receptor (GR) density in the CA1, CA3 and granule cell layer compared to virgin females. In addition, there was a main effect of stress on GR density in the CA3 region, with stressed females having significantly lower GR density compared to control females (p=.01). This work adds to our understanding of how stress and reproductive state affect plasticity in the female hippocampus.

An analysis of glucocorticoid receptor-mediated gene expression in BEAS-2B human airway epithelial cells identifies distinct, ligand-directed, transcription profiles with implications for asthma therapeutics.

International asthma guidelines recommend that inhaled glucocorticoids be used as a monotherapy in all patients with mild to moderate disease because of their ability to suppress airways inflammation. Current evidence suggests that the therapeutic benefit of glucocorticoids is due to the transactivation and transrepression of anti-inflammatory and pro-inflammatory genes respectively. However, the extent to which clinically relevant glucocorticoids are equivalent in their ability to modulate gene expression is unclear. A pharmacodynamics investigation of glucocorticoid receptor (GR)-mediated gene transactivation in BEAS-2B human airway epithelial cells was performed using a glucocorticoid response element luciferase reporter coupled with an analysis of glucocorticoid-inducible genes encoding proteins with anti-inflammatory and adverse-effect potential. Using transactivation as a functionally relevant output, a given glucocorticoid displayed a unique, gene expression 'fingerprint' where intrinsic efficacy and GR density were essential determinants. We showed that depending on the gene selected for analysis, a given glucocorticoid can behave as an antagonist, partial agonist, full agonist or even 'super agonist'. In the likely event that different, tissue-dependent gene expression profiles are reproduced in vivo, then the anti-inflammatory and adverse-effect potential of many glucocorticoids currently available as asthma therapeutics may not be equivalent. The generation of gene expression 'fingerprints' in target and off-target human tissues could assist the rational design of GR agonists with improved therapeutic ratios. This approach could identify compounds that are useful in the management of severe asthma and other inflammatory disorders where systemic exposure is desirable.

Hydrocortisone accelerates the decay of iconic memory traces: On the modulation of executive and stimulus-driven constituents of sensory information maintenance

A substantial amount of research documents the impact of glucocorticoids on higher-order cognitive functioning. By contrast, surprisingly little is known about the susceptibility of basic sensory processes to glucocorticoid exposure given that the glucocorticoid receptor density in the human visual cortex exceeds those observed in prefrontal and most hippocampal brain regions. As executive tasks also rely on these sensory processes, the present study investigates the impact of glucocorticoid exposure on different performance parameters characterizing the maintenance and transfer of sensory information from iconic memory (IM; the sensory buffer of the visual system) to working memory (WM). Using a crossover factorial design, we administered one out of three doses of hydrocortisone (0.06, 0.12, or 0.24mg/kg bodyweight) and a placebo to 18 healthy young men. Thereafter participants performed a partial report task, which was used to assess their individual ability to process sensory information. Blood samples were concurrently drawn to determine free and total cortisol concentrations. The compiled pharmacokinetic and psychophysical data demonstrates that free cortisol specifically accelerated the decay of sensory information (r=0.46) without significantly affecting the selective information transfer from IM to WM or the capacity limit of WM. Specifically, nonparametric regression revealed a sigmoid dose-response relationship between free cortisol levels during the testing period and the IM decay rates. Our findings highlight that glucocorticoid exposure may not only impact on the recruitment of top-down control for an active maintenance of sensory information, but alter their passive (stimulus-driven) maintenance thereby changing the availability of information prior to subsequent executive processing.