Glucocorticoid receptor gene, low-grade inflammation, and heart failure: the Heart and Soul study

Cardiometabolic Aspects of Congenital Adrenal Hyperplasia

Treatment of classic congenital adrenal hyperplasia (CAH) is directed at replacing deficient hormones and reducing androgen excess. However, even in the era of early diagnosis and lifelong hormonal substitution, the presence of CAH is still associated with numerous complications and also with increased mortality. The aim of this article was to create an authoritative and balanced review concerning cardiometabolic risk in patients with CAH. The authors searched all major databases and scanned reference lists of all potentially eligible articles to find relevant articles. The risk was compared with that in other forms of adrenal insufficiency. The reviewed articles, most of which were published recently, provided conflicting results, which can be partially explained by differences in the inclusion criteria and treatment, small sample sizes, and gene-environment interactions. However, many studies showed that the presence of CAH is associated with an increased risk of weight gain, worsening of insulin sensitivity, high blood pressure, endothelial dysfunction, early atherosclerotic changes in the vascular wall, and left ventricular diastolic dysfunction. These complications were more consistently reported in patients with classic than nonclassic CAH and were in part related to hormonal and functional abnormalities associated with this disorder and/or to the impact of overtreatment and undertreatment. An analysis of available studies suggests that individuals with classic CAH are at increased cardiometabolic risk. Excess cardiovascular and metabolic morbidity is likely multifactorial, related to glucocorticoid overtreatment, imperfect adrenal hormone replacement therapy, androgen excess, and adrenomedullary failure. Cardiometabolic effects of new therapeutic approaches require future targeted studies.

Adrenal crisis-induced cardiogenic shock (ACCS): a comprehensive review

Adrenal insufficiency (AI) is a disorder in which inadequate glucocorticoid and mineralocorticoid hormone production leads to a variety of symptoms, including fatigue, weight loss, and nausea. In some patients with unknown AI, adrenal crisis-induced cardiogenic shock (ACCS) can be the first presentation, resulting in a fatal situation. The ACCS may exhibit unresponsiveness to inotropes and fluid therapy; thus, glucocorticoid administration is the primary vital intervention, making early detection of AI essential. Hence, in this study, we review the case reports demonstrating acute cardiomyopathies in the context of AI. The review addresses the suggested underlying mechanisms, including the diminished protective effects of glucocorticoids against catecholamines in AI. We also highlighted some clues to aid physicians in considering AI as a differential diagnosis in critically ill patients presenting cardiogenic shock.

Corticosteroid Receptors in Cardiac Health and Disease

Nuclear receptors play a central role in both energy metabolism and cardiomyocyte death and survival in the heart. Recent evidence suggests they may also influence cardiomyocyte endowment. Although several members of the nuclear receptor family play key roles in heart maturation (including thyroid hormone receptors) and cardiac metabolism, here, the focus will be on the corticosteroid receptors, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). The heart is an important target for the actions of corticosteroids, yet the homeostatic role of GR and MR in the healthy heart has been elusive. However, MR antagonists are important in the treatment of heart failure, a condition associated with mitochondrial dysfunction and energy failure in cardiomyocytes leading to mitochondria-initiated cardiomyocyte death (Ingwall and Weiss, Circ Res 95:135-145, 2014; Ingwall , Cardiovasc Res 81:412-419, 2009; Zhou and Tian , J Clin Invest 128:3716-3726, 2018). In contrast, animal studies suggest GR activation in cardiomyocytes has a cardioprotective role, including in heart failure.

Generalized and tissue specific glucocorticoid resistance

Glucocorticoids (GCs) are steroid hormones that influence several physiologic functions and are among the most frequently prescribed drugs worldwide. Resistance to GCs has been observed in the context of the familial generalized GC resistance (Chrousos' syndrome) or tissue specific GC resistance in chronic inflammatory states. In this review, we have summarized the major factors that influence individual glucocorticoid sensitivity/resistance. The fine-tuning of GC action is determined in a tissue-specific fashion that includes the combination of different GC receptor promoters, translation initiation sites, splice isoforms, interacting proteins, post-translational modifications, and alternative mechanisms of signal transduction.

Glucocorticoid Signaling and the Aging Heart

A decline in normal physiological functions characterizes the aging process. While some of these changes are benign, the decrease in the function of the cardiovascular system that occurs during aging leads to the activation of pathological processes associated with an increased risk for heart disease and its complications. Imbalances in endocrine function are also common occurrences during the aging process. Glucocorticoids are primary stress hormones and are critical regulators of energy metabolism, inflammation, and cardiac function. Glucocorticoids exert their actions by binding the glucocorticoid receptor (GR) and, in some instances, to the mineralocorticoid receptor (MR). GR and MR are members of the nuclear receptor family of ligand-activated transcription factors. There is strong evidence that imbalances in GR and MR signaling in the heart have a causal role in cardiac disease. The extent to which glucocorticoids play a role in the aging heart, however, remains unclear. This review will summarize the positive and negative direct and indirect effects of glucocorticoids on the heart and the latest molecular and physiological evidence on how alterations in glucocorticoid signaling lead to changes in cardiac structure and function. We also briefly discuss the effects of other hormones systems such as estrogens and GH/IGF-1 on different cardiovascular cells during aging. We will also review the link between imbalances in glucocorticoid levels and the molecular processes responsible for promoting cardiomyocyte dysfunction in aging. Finally, we will discuss the potential for selectively manipulating glucocorticoid signaling in cardiomyocytes, which may represent an improved therapeutic approach for preventing and treating age-related heart disease.

Role of the glucocorticoid receptor in glomerular disease

Glucocorticoids are potent anti-inflammatory agents that are commonly used in the treatment of various glomerular diseases. Data from in vitro and in vivo studies, in both animals and humans, convincingly demonstrate that glucocorticoids have many beneficial direct effects on glomeruli, including podocytes, suggesting that, in theory, systemic administration is not necessary to achieve therapeutic benefit. Indeed, it is increasingly recognized that systemic steroids often have an unfavorable risk-to-benefit ratio. As we move into an age of personalized medicine, strategies to develop targeted steroid delivery systems and individualized risk assessment algorithms are desirable in clinicians' efforts to "first, do no harm."

Circulating Interleukin-6 concentration covaries inversely with self-reported sleep duration as a function of polymorphic variation in the glucocorticoid receptor

Growing evidence links extremes of self-reported sleep duration with higher circulating markers of inflammatory disease risk, although not all findings are consistent. Extremes of sleep duration also associate with activation of the hypothalamic-pituitary-adrenocortical (HPA) system and the peripheral release of cortisol, a glucocorticoid (GC) important in downregulating transcription of pro-inflammatory molecules. Polymorphic variation in the gene encoding the GC receptor (GR; NR3C1) modulates cellular sensitivity to GC-mediated anti-inflammatory signaling, thereby affecting levels of pro-inflammatory molecules. Thus, we hypothesized that extremes of self-reported sleep duration may covary with circulating levels of inflammatory markers as a function of allelic variation in NR3C1. Specifically, we examine the possibility that a single nucleotide polymorphism of the GR gene-(rs6198), the minor (G) allele of which confers reduced GR sensitivity-moderates an association of sleep duration with interleukin (IL)-6 and C-reactive protein (CRP) among a large sample (IL-6: N = 857; CRP: N = 929) of midlife community volunteers of European ancestry. Findings showed that sleep duration varied inversely with IL-6 (β = -0.087, p = .012), and this association was stronger among individuals homozygous for the rs6198 G-allele compared to alternate genotypes (β = -0.071, p = .039). We also found that sleep duration showed a U-shaped association with CRP (polynomial term: β = 0.093, p = .006), which was not moderated by rs6198 genotype. In conclusion, we show that a common genetic variant in the GR moderates an inverse association of self-reported sleep duration with circulating IL-6, possibly contributing to the increased disease risk observed among some short sleepers.

Cardiomyocyte glucocorticoid and mineralocorticoid receptors directly and antagonistically regulate heart disease in mice

Stress is increasingly associated with heart dysfunction and is linked to higher mortality rates in patients with cardiometabolic disease. Glucocorticoids are primary stress hormones that regulate homeostasis through two nuclear receptors, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR), both of which are present in cardiomyocytes. To examine the specific and coordinated roles that these receptors play in mediating the direct effects of stress on the heart, we generated mice with cardiomyocyte-specific deletion of GR (cardioGRKO), MR (cardioMRKO), or both GR and MR (cardioGRMRdKO). The cardioGRKO mice spontaneously developed cardiac hypertrophy and left ventricular systolic dysfunction and died prematurely from heart failure. In contrast, the cardioMRKO mice exhibited normal heart morphology and function. Despite the presence of myocardial stress, the cardioGRMRdKO mice were resistant to the cardiac remodeling, left ventricular dysfunction, and early death observed in the cardioGRKO mice. Gene expression analysis revealed the loss of gene changes associated with impaired Ca²⁺ handling, increased oxidative stress, and enhanced cell death and the presence of gene changes that limited the hypertrophic response and promoted cardiomyocyte survival in the double knockout hearts. Reexpression of MR in cardioGRMRdKO hearts reversed many of the cardioprotective gene changes and resulted in cardiac failure. These findings reveal a critical role for balanced cardiomyocyte GR and MR stress signaling in cardiovascular health. Therapies that shift stress signaling in the heart to favor more GR and less MR activity may provide an improved approach for treating heart disease.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Generating diversity in human glucocorticoid signaling through a racially diverse polymorphism in the beta isoform of the glucocorticoid receptor

Alternative splicing of the human glucocorticoid receptor gene generates two isoforms, hGRα and hGRβ. hGRβ functions as a dominant-negative regulator of hGRα activity and but also has inherent transcriptional activity, collectively altering glucocorticoid sensitivity. Single-nucleotide polymorphisms in the 3' UTR of hGRβ have been associated with altered receptor protein expression, glucocorticoid sensitivity, and disease risk. Characterization of the hGRβ G3134T polymorphism has been limited to a relatively small, homogenous population. The objective of this study was to determine the prevalence of hGRβ G3134T in a diverse population and assess the association of hGRβ G3134T in this population with physiological outcomes. In a prospective cohort study, 3730 genetically diverse participants were genotyped for hGRβ G3134T and four common GR polymorphisms. A subset of these participants was evaluated for clinical and biochemical measurements. Immortalized human osteosarcoma cells (U-2 OS), stably transfected with wild-type or G3134T hGRβ, were evaluated for receptor expression, stability, and genome-wide gene expression. Glucocorticoid-mediated gene expression profiles were investigated in primary macrophages isolated from participants. In a racially diverse population, the minor allele frequency was 74% (50.7% heterozygous carriers and 23.3% homozygous minor allele), with a higher prevalence in Caucasian non-Hispanic participants. After adjusting for confounding variable, carriers of hGRβ G3134T were more likely to self-report allergies, have higher serum cortisol levels, and reduced cortisol suppression in response to low-dose dexamethasone. The presence of hGRβ G3134T in U-2 OS cells increased hGR mRNA stability and protein expression. Microarray analysis revealed that the presence of the hGRβ G3134T polymorphism uniquely altered gene expression profiles in U-2 OS cells and primary macrophages. hGRβ G3134T is significantly present in the study population and associated with race, self-reported disease, and serum levels of glucocorticoids. Underlying these health differences may be changes in gene expression driven by altered receptor stability.

Cardiac GR and MR: From Development to Pathology

The efficacy of mineralocorticoid receptor (MR) antagonism in the treatment of certain patients with heart failure has highlighted the pivotal role of aldosterone and MR in heart disease. The glucocorticoid (GC) receptor (GR) is also expressed in heart, but the role of cardiac GR had received much less attention until recently. GR and MR are highly homologous in both structure and function, although not in cellular readout. Recent evidence in animal models has uncovered a tonic role for GC action via GR in cardiomyocytes in prevention of heart disease. Here, we review this evidence and the implications for a balance between GR and MR activation in the early life maturation of the heart and its subsequent health and disease.

Glucocorticoid signaling in the heart: A cardiomyocyte perspective

Heart failure is one of the leading causes of death in the Western world. Glucocorticoids are primary stress hormones that regulate a vast array of biological processes, and synthetic derivatives of these steroids have been mainstays in the clinic for the last half century. Abnormal levels of glucocorticoids are known to negatively impact the cardiovascular system; however, surprisingly little is known about the direct role of glucocorticoid signaling in the heart. The actions of glucocorticoids are mediated classically by the glucocorticoid receptor (GR). In certain cells, such as cardiomyocytes, glucocorticoid occupancy and activation of the mineralocorticoid receptor (MR) may also contribute to the observed response. Recently, there has been a surge of reports investigating the in vivo function of glucocorticoid signaling in the heart using transgenic mice that specifically target GR or MR in cardiomyocytes. Results from these studies suggest that GR signaling in cardiomyocytes is critical for the normal development and function of the heart. In contrast, MR signaling in cardiomyocytes participates in the development and progression of cardiac disease. In the following review, we discuss these genetic mouse models and the new insights they are providing into the direct role cardiomyocyte glucocorticoid signaling plays in heart physiology and pathophysiology. This article is part of a Special Issue entitled 'Steroid Perspectives'.

MicroRNAs in the Myocyte Enhancer Factor 2 (MEF2)-regulated Gtl2-Dio3 Noncoding RNA Locus Promote Cardiomyocyte Proliferation by Targeting the Transcriptional Coactivator Cited2

Understanding cell cycle regulation in postmitotic cardiomyocytes may lead to new therapeutic approaches to regenerate damaged cardiac tissue. We have demonstrated previously that microRNAs encoded by the Gtl2-Dio3 noncoding RNA locus function downstream of the MEF2A transcription factor in skeletal muscle regeneration. We have also reported expression of these miRNAs in the heart. Here we investigated the role of two Gtl2-Dio3 miRNAs, miR-410 and miR-495, in cardiac muscle. Overexpression of miR-410 and miR-495 robustly stimulated cardiomyocyte DNA synthesis and proliferation. Interestingly, unlike our findings in skeletal muscle, these miRNAs did not modulate the activity of the WNT signaling pathway. Instead, these miRNAs targeted Cited2, a coactivator required for proper cardiac development. Consistent with miR-410 and miR-495 overexpression, siRNA knockdown of Cited2 in neonatal cardiomyocytes resulted in robust proliferation. This phenotype was associated with reduced expression of Cdkn1c/p57/Kip2, a cell cycle inhibitor, and increased expression of VEGFA, a growth factor with proliferation-promoting effects. Therefore, miR-410 and miR-495 are among a growing number of miRNAs that have the ability to potently stimulate neonatal cardiomyocyte proliferation.

Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.

Genetic and in vivo determinants of glucocorticoid sensitivity in relation to clinical outcome of childhood nephrotic syndrome

Following initial glucocorticoid treatment, the clinical course in children with nephrotic syndrome is highly variable. Intrinsic sensitivity to glucocorticoids might be a determinant of this variability. Functional polymorphisms of the glucocorticoid receptor gene NR3C1 have been associated with either relatively impaired (GR-9β) or increased (BclI) glucocorticoid sensitivity. Here, in a prospective, well-defined cohort of children with nephrotic syndrome, we evaluated both carriage of GR-9β+TthIII-1 and BclI haplotypes in 113 children and a dexamethasone suppression test in 90 children in relation to their clinical outcome over a median follow-up of 4.4 years. Carriers of GR-9β+TthIII-1 had a significantly higher incidence of steroid dependence 13/25 (52%) compared with noncarriers 19/75 (25%) with a hazard ratio adjusted for gender, age, and descent of 3.04 with 95% confidence interval 1.37-6.74. Both first and frequent relapses happened significantly more often in GR-9β+TthIII-1 carriers than in noncarriers. There were no significant differences in therapeutic outcomes between carriers and noncarriers of the BclI haplotype. Results of the dexamethasone test showed no associations with clinical outcome. Thus, the GR-9β+TthIII-1 haplotype of the glucocorticoid receptor gene offers new insights into the clinical course of children with nephrotic syndrome.

Glucocorticoid sensitivity in health and disease

Glucocorticoids regulate many physiological processes and have an essential role in the systemic response to stress. For example, gene transcription is modulated by the glucocorticoid-glucocorticoid receptor complex via several mechanisms. The ultimate biologic responses to glucocorticoids are determined by not only the concentration of glucocorticoids but also the differences between individuals in glucocorticoid sensitivity, which is influenced by multiple factors. Differences in sensitivity to glucocorticoids in healthy individuals are partly genetically determined by functional polymorphisms of the gene that encodes the glucocorticoid receptor. Hereditary syndromes have also been identified that are associated with increased and decreased sensitivity to glucocorticoids. As a result of their anti-inflammatory properties, glucocorticoids are widely used in the treatment of allergic, inflammatory and haematological disorders. The variety in clinical responses to treatment with glucocorticoids reflects the considerable variation in glucocorticoid sensitivity between individuals. In immune-mediated disorders, proinflammatory cytokines can induce localized resistance to glucocorticoids via several mechanisms. Individual differences in how tissues respond to glucocorticoids might also be involved in the predisposition for and pathogenesis of the metabolic syndrome and mood disorders. In this Review, we summarize the mechanisms that influence glucocorticoid sensitivity in health and disease and discuss possible strategies to modulate glucocorticoid responsiveness.

Essential role of stress hormone signaling in cardiomyocytes for the prevention of heart disease

Heart failure is a leading cause of death in humans, and stress is increasingly associated with adverse cardiac outcomes. Glucocorticoids are primary stress hormones, but their direct role in cardiovascular health and disease is poorly understood. To determine the in vivo function of glucocorticoid signaling in the heart, we generated mice with cardiomyocyte-specific deletion of the glucocorticoid receptor (GR). These mice are born at the expected Mendelian ratio, but die prematurely from spontaneous cardiovascular disease. By 3 mo of age, mice deficient in cardiomyocyte GR display a marked reduction in left ventricular systolic function, as evidenced by decreases in ejection fraction and fractional shortening. Heart weight and left ventricular mass are elevated, and histology revealed cardiac hypertrophy without fibrosis. Removal of endogenous glucocorticoids and mineralocorticoids neither augmented nor lessened the hypertrophic response. Global gene expression analysis of knockout hearts before pathology onset revealed aberrant regulation of a large cohort of genes associated with cardiovascular disease as well as unique disease genes associated with inflammatory processes. Genes important for maintaining cardiac contractility, repressing cardiac hypertrophy, promoting cardiomyocyte survival, and inhibiting inflammation had decreased expression in the GR-deficient hearts. These findings demonstrate that a deficiency in cardiomyocyte glucocorticoid signaling leads to spontaneous cardiac hypertrophy, heart failure, and death, revealing an obligate role for GR in maintaining normal cardiovascular function. Moreover, our findings suggest that selective activation of cardiomyocyte GR may represent an approach for the prevention of heart disease.

The biology of the glucocorticoid receptor: new signaling mechanisms in health and disease

Glucocorticoids are primary stress hormones necessary for life that regulate numerous physiologic processes in an effort to maintain homeostasis. Synthetic derivatives of these hormones have been mainstays in the clinic for treating inflammatory diseases, autoimmune disorders, and hematologic cancers. The physiologic and pharmacologic actions of glucocorticoids are mediated by the glucocorticoid receptor (GR), a member of the nuclear receptor superfamily of ligand-dependent transcription factors. Ligand-occupied GR induces or represses the transcription of thousands of genes through direct binding to DNA response elements, physically associating with other transcription factors, or both. The traditional view that glucocorticoids act through a single GR protein has changed dramatically with the discovery of a large cohort of receptor isoforms with unique expression, gene-regulatory, and functional profiles. These GR subtypes are derived from a single gene by means of alternative splicing and alternative translation initiation mechanisms. Posttranslational modification of these GR isoforms further expands the diversity of glucocorticoid responses. Here we discuss the origin and molecular properties of the GR isoforms and their contribution to the specificity and sensitivity of glucocorticoid signaling in healthy and diseased tissues.

Glucocorticoid receptor is required for foetal heart maturation

Glucocorticoids are vital for the structural and functional maturation of foetal organs, yet excessive foetal exposure is detrimental to adult cardiovascular health. To elucidate the role of glucocorticoid signalling in late-gestation cardiovascular maturation, we have generated mice with conditional disruption of glucocorticoid receptor (GR) in cardiomyocytes and vascular smooth muscle cells using smooth muscle protein 22-driven Cre recombinase (SMGRKO mice) and compared them with mice with global deficiency in GR (GR(-/-)). Echocardiography shows impaired heart function in both SMGRKO and GR(-/-) mice at embryonic day (E)17.5, associated with generalized oedema. Cardiac ultrastructure is markedly disrupted in both SMGRKO and GR(-/-) mice at E17.5, with short, disorganized myofibrils and cardiomyocytes that fail to align in the compact myocardium. Failure to induce critical genes involved in contractile function, calcium handling and energy metabolism underpins this common phenotype. However, although hearts of GR(-/-) mice are smaller, with 22% reduced ventricular volume at E17.5, SMGRKO hearts are normally sized. Moreover, while levels of mRNA encoding atrial natriuretic peptide are reduced in E17.5 GR(-/-) hearts, they are normal in foetal SMGRKO hearts. These data demonstrate that structural, functional and biochemical maturation of the foetal heart is dependent on glucocorticoid signalling within cardiomyocytes and vascular smooth muscle, though some aspects of heart maturation (size, ANP expression) are independent of GR at these key sites.

Primary generalized familial and sporadic glucocorticoid resistance (Chrousos syndrome) and hypersensitivity

Familial or sporadic primary generalized glucocorticoid resistance or Chrousos syndrome is a rare genetic condition characterized by generalized, partial, target-tissue insensitivity to glucocorticoids and a consequent hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis. Primary generalized glucocorticoid hypersensitivity (PGGH) represents the mirror image of the former, and is characterized by generalized, partial, target-tissue hypersensitivity to glucocorticoids, and compensatory hypoactivation of the HPA axis. The molecular basis of both conditions has been ascribed to mutations in the human glucocorticoid receptor (hGR) gene, which impair the molecular mechanisms of hGR action and alter tissue sensitivity to glucocorticoids. This review summarizes the pathophysiology, molecular mechanisms and clinical aspects of Chrousos syndrome and PGGH.

Acute and chronic stress induced changes in sensitivity of peripheral inflammatory pathways to the signals of multiple stress systems --2011 Curt Richter Award Winner

Exposure to psychosocial stress has been associated with increasing rates of morbidity in humans and in animal models, but the underlying mechanisms are not completely understood. Major stress responsive systems, such as the hypothalamus-pituitary adrenal (HPA) axis and the autonomic nervous system (ANS) are under investigation as underlying pathways, but although acute stress reliably activates these systems, findings of long-term alternations in baseline activity are inconsistent at present. Emerging evidence suggests that stress-related changes in the sensitivity of target systems toward glucocorticoid (GC) regulation, i.e. development of GC resistance, might help explain inflammatory disinhibition and development of disease related to inflammation. More recent findings further show that the autonomic nervous system might play an important role in the regulatory control of the inflammatory cascade. The major argument put forward in this manuscript is that target tissues for stress system modulation, such as the inflammatory cascade, vary in their ability to respond to stress system signaling, and that assessing alterations in this stress signal sensitivity which can be caused by stress or disease processes, might be necessary to understand and explain stress effects on health. This review focuses on the inflammatory system in particular, because anti-inflammatory effects of most stress systems have been documented, but the general assumption might have to be generalized to other target systems. The main conclusion to be made is that reduction in glucocorticoid sensitivity of target tissues is the most consistent finding at present, and that assessing such changes in glucocorticoid sensitivity might be necessary to understand many stress-related changes in physiology.

Glucocorticoid sensitivity in mood disorders

In this review, we provide an overview of recent literature on glucocorticoid (GC) sensitivity in mood disorders. Assessing GC sensitivity is often performed by measuring the cortisol awakening rise (CAR), by challenging the hypothalamic-pituitary-adrenal (HPA) axis using a dexamethasone suppression test (DST) or a dexamethasone/cortisol-releasing hormone test (DEX/CRH); more recently by measuring cortisol as a retrospective calendar in scalp hair. The main findings in mood disorders are higher mean cortisol levels in hair samples and a higher CAR, showing a hyperactivity of the HPA axis. This is in line with the mild resistance for GCs previously observed in challenge tests during mood episodes. GC sensitivity is partly determined by polymorphisms in the genes encoding receptors and other proteins involved in the regulation of the HPA axis. We shortly discuss the glucocorticoid receptor, as well as the mineralocorticoid receptor, the cortisol-releasing hormone receptor-1, and the glucocorticoid receptor co-chaperone FKBP5. Data clearly indicate genetic changes, along with epigenetic changes which influence the set-point and regulation of the HPA axis. Early trauma, as well as influences in utero, appears to be important. Future research is necessary to further clarify the biological background and consequences of an individual's cortisol exposure in relation to mood.

Glucocorticoid receptor-9beta polymorphism is associated with systolic blood pressure and heart growth during early childhood. The Generation R Study

BACKGROUND

glucocorticoid receptor-9β polymorphism (rs6198) is associated with the susceptibility for cardiovascular disease.

AIM

to examine whether the GR-9 β variant is also associated with blood pressure and heart growth in early childhood.

STUDY DESIGN

this study was embedded in a population-based prospective cohort study from fetal life onwards. Analyses were based on 857 children.

OUTCOME MEASURES

Left cardiac structures (aortic root diameter, left atrial diameter and left ventricular mass), shortening fraction and heart beat were measured postnatally at the ages of 1.5, 6 and 24 months. Blood pressure was measured at 24 months of age.

RESULTS

the distribution of the GR-9β genotype showed 75.1% homozygous reference, 23.5% heterozygous and 1.4% homozygous variant subjects. No differences in cardiovascular outcomes were observed at the ages of 1.5 and 6 months. At the age of 24 months, homozygous variants showed an increased systolic blood pressure of 2.65 mmHg (95% CI: 0.16, 5.14), an increased heart rate of 9.10 beats per minute (95% CI: 1.28, 16.7) and an increased left ventricular mass of 4.99 g (95% CI: 1.33, 8.65) compared to homozygous references. This means an increase of 2.6%, 8.6% and 16%, respectively. GR-9 β polymorphism was significantly associated with left ventricular mass growth during the first 2 years.

CONCLUSION

our findings suggest that genetically determined differences in cortisol exposure affect cardiovascular development in early life.

Research resource: nuclear receptor atlas of human retinal pigment epithelial cells: potential relevance to age-related macular degeneration

Retinal pigment epithelial (RPE) cells play a vital role in retinal physiology by forming the outer blood-retina barrier and supporting photoreceptor function. Retinopathies including age-related macular degeneration (AMD) involve physiological and pathological changes in the epithelium, severely impairing the retina and effecting vision. Nuclear receptors (NRs), including peroxisome proliferator-activated receptor and liver X receptor, have been identified as key regulators of physiological pathways such as lipid metabolic dysregulation and inflammation, pathways that may also be involved in development of AMD. However, the expression levels of NRs in RPE cells have yet to be systematically surveyed. Furthermore, cell culture lines are widely used to study the biology of RPE cells, without knowledge of the differences or similarities in NR expression and activity between these in vitro models and in vivo RPE. Using quantitative real-time PCR, we assessed the expression patterns of all 48 members of the NR family plus aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator in human RPE cells. We profiled freshly isolated cells from donor eyes (in vivo), a spontaneously arising human cell line (in vitro), and primary cell culture lines (in vitro) to determine the extent to which NR expression in the cultured cell lines reflects that of in vivo. To evaluate the validity of using cell culture models for investigating NR receptor biology, we determined transcriptional activity and target gene expression of several moderately and highly expressed NRs in vitro. Finally, we identified a subset of NRs that may play an important role in pathobiology of AMD.