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Expression of mRNA for myotrophin, endothelial nitric oxide synthase (eNOS, NOS-3), and VEGF in left ventricles from fetuses of the control (white bars), high (black bars), and low maternal cortisol (gray bars) groups. Data are expressed as in Fig. 1. *P 0.05 vs. control.
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Moderately elevated maternal cortisol levels late in gestation cause enlargement of the fetal sheep heart. We have used quantitative real-time PCR to examine expression of candidate genes in fetal hearts from mothers in whom cortisol levels were increased (by infusion of 1 mg cortisol.kg(-1).day(-1)) or decreased (by adrenalectomy and replacement t...
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Context 1
... NOS-3, and VEGF. Expression of myotrophin, NOS-3, and VEGF mRNA in left ventricle were all unchanged in response to high or low maternal cortisol levels (Fig. ...
Context 2
... to be related to growth were not found to be increased. We reasoned that since the fetal hearts were enlarged in the high cortisol group, perhaps angiogenesis was being stimulated by VEGF and NOS-3 in these hearts; however, neither of these genes was significantly increased in fetal left ventricle among the maternal cortisol treatment groups (Fig. 2). Myotrophin was also not increased in the enlarged hearts (Fig. 2). Myotrophin has been suggested as a causal agent in cardiac hypertrophy in both humans and in rodents (1,46,53). In mice, overexpression of myotrophin causes cardiac hypertrophy, and pressure overload causes a ventricle-specific increase in myotrophin, as well as wall ...
Context 3
... that since the fetal hearts were enlarged in the high cortisol group, perhaps angiogenesis was being stimulated by VEGF and NOS-3 in these hearts; however, neither of these genes was significantly increased in fetal left ventricle among the maternal cortisol treatment groups (Fig. 2). Myotrophin was also not increased in the enlarged hearts (Fig. 2). Myotrophin has been suggested as a causal agent in cardiac hypertrophy in both humans and in rodents (1,46,53). In mice, overexpression of myotrophin causes cardiac hypertrophy, and pressure overload causes a ventricle-specific increase in myotrophin, as well as wall thick- ness. Treatment of cultures of neonatal myoctes with myotro- ...
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Fetal exposure to maternal glucocorticoids may determine fetal growth and the programing of later disorders. Availability of the glucocorticoids in the placenta is regulated by the 11beta-hydroxysteroid dehydrogenase (11beta-HSDs) enzymes. To date, there are discrepancies with regard to cortisol (F) cord blood levels in fetuses with intrauterine gr...
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We investigated the effe...
Citations
... Activation of the glucocorticoid receptor (GR) by cortisol is regulated by the enzymatic activity of both 11BHSD1 and 11BHSD2. Both GR and 11BHSD1 are abundantly expressed in cardiomyocytes and blood vessels within the fetal heart, whereas 11BHSD2 is localized more predominantly in blood vessels than cardiomyocytes (Reini et al. 2006), demonstrating that cortisol has access to the developing heart. However, although LGUN increased maternal plasma cortisol concentrations for the first 10 days of the nutritional regime; fetal plasma cortisol concentrations were not increased. ...
Key points:
This study investigates the impact of decreased fetal plasma glucose concentrations on the developing heart in late gestation, by subjecting pregnant ewes to a 50% global nutrient restriction. Late gestation undernutrition (LGUN) decreased fetal plasma glucose concentrations whilst maintaining a normoxemic blood gas status. LGUN increased the mRNA expression of IGF2 and IGF2R. Fetal plasma glucose concentrations, but not fetal blood pressure, were significantly correlated with IGF2 expression and the activation of CAMKII in the fetal right ventricle. LGUN increased interstitial collagen deposition and altered the protein abundance of phospho-PLB and phospho-troponin I, regulators of cardiac contractility and relaxation. This study shows that a decrease in fetal plasma glucose concentrations may play a role in the development of detrimental changes in the right ventricle in early life, highlighting CAMKII as a potential target for the development of intervention strategies.
Abstract:
Exposure of the fetus to a range of environmental stressors, including maternal undernutrition, is associated with an increased risk of death from cardiovascular disease in adult life. This study aimed to determine the effect of maternal nutrient restriction in late gestation on the molecular mechanisms that regulate cardiac growth and development of the fetal heart. Maternal undernutrition resulted in a decrease in fetal glucose concentrations across late gestation, whilst fetal arterial PO2 remained unchanged between the control and late gestation undernutrition (LGUN) groups. There was evidence of an up-regulation of IGF2/IGF2R signalling through the CAMKII pathway in the fetal right ventricle in the LGUN group, suggesting an increase in hypertrophic signalling. LGUN also resulted in an increased mRNA expression of COL1A, TIMP1 and TIMP3 in the right ventricle of the fetal heart. In addition, there was an inverse relationship between fetal glucose concentrations and COL1A expression. The presence of interstitial fibrosis in the heart of the LGUN group was confirmed through the quantification of picrosirius red-stained sections of the right ventricle. We have therefore shown that maternal undernutrition in late gestation may drive the onset of myocardial remodelling in the fetal right ventricle and thus has negative implications for right ventricle function and cardiac health in later life.
... 24,28 Um estudo em fetos de ovelhas mostrou que os receptores mineralocorticoides (MR) e GC (GR), assim como o 11β-HSD1, são expressos abundantemente nos miócitos e nos vasos sanguíneos cardíacos. 29 Os autores sugeriram que O sistema renina-angiotensina (RAS) desempenha um papel importante nas formas primária e secundária de hipertensão. Os componentes do RAS, como a enzima conversora da angiotensina (IECA) e a angiotensina II, são produzidos localmente nos tecidos cardíacos 31 e são candidatos primários a fatores promotores de remodelação, principalmente hipertrofia cardíaca de miócitos e aumento da fibrose extracelular, que levam à deterioração da função cardíaca. ...
Background:
The dietary limitation during pregnancy influences the growth and development of the fetus and offspring and their health into adult life. The mechanisms underlying the adverse effects of gestational protein restriction (GPR) in the development of the offspring hearts are not well understood.
Objectives:
The aim of this study was to evaluate the effects of GPR on cardiac structure in male rat offspring at day 60 after birth (d60).
Methods:
Pregnant Wistar rats were fed a normal-protein (NP, 17% casein) or low-protein (LP, 6% casein) diet. Blood pressure (BP) values from 60-day-old male offspring were measured by an indirect tail-cuff method using an electro sphygmomanometer. Hearts (d60) were collected for assessment of connexin 43 (Cx43) mRNA expression and morphological and morphometric analysis.
Results:
LP offspring showed no difference in body weight, although they were born lighter than NP offspring. BP levels were significantly higher in the LP group. We observed a significant increase in the area occupied by collagen fibers, a decrease in the number of cardiomyocytes by 10⁴µm², and an increase in cardiomyocyte area associated with an increased Cx43 expression.
Conclusion:
GPR changes myocardial levels of Cx43 mRNA in male young adult rats, suggesting that this mechanism aims to compensate the fibrotic process by the accumulation of collagen fibers in the heart interstitium.
... Spontaneous decrease in FHR can occur in cases of supraventricular tachycardia/flutter. 7 However, antenatal corticosteroids have a direct, but transient effect on FHR. 8 Maternal cortisol infusion induces increase in fetal heart size and wall thickness in sheep. 9 These effects of corticosteroid on haemodynamics may cause a decrease in FHR. Moreover, corticosteroid therapy with β-methasone was reported to be effective for treatment of HF associated with congenital pulmonary airway malformation (CPAM) 10 11 and is recommended for the treatment of HF associated with CPAM. 2 These observations together with the clinical course of our case raised the possibility that corticosteroid therapy contributed to the resolution of HF in the present case with tachyarrhythmia. ...
A case of hydrops fetalis (HF) that resolved after corticosteroid therapy despite persisting fetal tachycardia of 190 bpm is reported. The fetus with confirmed normal karyotype had HF in the presence of atrial flutter and sustained ventricular rate of 200-210 bpm at gestational week (GW) 31(-6/7). Aetiologies of HF other than fetal tachyarrhythmia were unlikely in this infant. The patient's family declined pharmacological treatment with maternal digoxin and desired to continue pregnancy with only intensive monitoring of fetal condition. Maternal transplacental β-methasone was given to facilitate fetal lung maturation. The fetal tachyarrhythmia ameliorated to 190 bpm at GW 32(-5/7) and HF gradually disappeared by birth. The otherwise healthy female neonate weighing 3050 g born at GW 37(-0/7) was successfully treated with cardioversion performed 60 min after birth. This case suggested that corticosteroid therapy contributed to the resolution of HF associated with tachyarrhythmia. 2015 BMJ Publishing Group Ltd.
... One hypothesis for the effects of cortisol on the fetal heart was that increasing cortisol 1.5-fold between 120 and 130 days gestation (47) produces cardiac enlargement primarily by accelerating the normal late-gestational maturation of the heart; however, the transcriptomic analysis suggests that although some genes altered by cortisol at 130 days are those altered at 140 days in the control fetuses, this hypothesis is an oversimplification of the effect of cortisol on the fetal heart. In our earlier studies the effects of maternal cortisol did not correspond to the changes found with maturation when a subset of genes related to IGF and angiotensin were considered (48,49). ...
We have previously shown in sheep that 10 days of modest chronic increase in maternal cortisol resulting from maternal infusion of cortisol (1 mg/kg/d) caused fetal heart enlargement and Purkinje cell apoptosis. In subsequent studies we extended the cortisol infusion to term, finding a dramatic incidence of stillbirth in the pregnancies with chronically increased cortisol. To investigate effects of maternal cortisol on the heart, transcriptomic analyses were performed on the septa using ovine microarrays and Webgestalt and Cytoscape programs for pathway inference. Analyses of the transcriptomic effects of maternal cortisol infusion for 10days (130d-cortisol vs 130d-control), or ~25 days (140d-cortisol vs 140d-control) and of normal maturation (140d-control vs 130d- control) were performed. Gene ontology terms related to immune function and cytokine actions were significantly overrepresented as genes altered by both cortisol and maturation in the septa. After 10 days of cortisol, growth factor and muscle cell apoptosis pathways were significantly overrepresented, consistent with our previous histologic findings. In the term fetuses ( ~25 days of cortisol) nutrient pathways were significantly overrepresented, consistent with altered metabolism and reduced mitochondria. Analysis of mitochondrial number by mitochondrial DNA expression confirmed a significant decrease in mitochondria. The metabolic pathways modeled as altered by cortisol treatment to term were different from those modeled during maturation of the heart to term, and thus changes in gene expression in these metabolic pathways may be indicative of the fetal heart pathophysiologies seen in pregnancies complicated by stillbirth, including gestational diabetes, Cushing's disease and chronic stress.
... In many epithelial tissues, MRs are protected from binding by cortisol because of dehydrogenase activity of 11-hydroxysteroid dehydrogenase type II (11HSD2) (42,45). However, we have previously found (47) that the fetal heart expresses both MR and GR and has relatively low expression of 11HSD2 and relatively high expression of the complementary enzyme 11HSD1, which has predominant reductase activity; in comparison fetal kidney at 130 days of gestation had 13-fold lower expression of MR and 750-fold higher expression of 11HSD2 (47). Therefore, it would be expected that cortisol action in the fetal heart could be mediated by both MR and GR. ...
We have previously found that modest chronic increases in maternal cortisol result in an enlarged fetal heart. In order to explore the mechanisms of this effect, we used intrapericardial infusions of a mineralocorticoid receptor (MR) antagonist (canrenoate) or of a glucocorticoid receptor (GR) antagonist (mifepristone) in the fetus during maternal infusion of cortisol (1 mg/kg/d). We have shown that the MR antagonist blocked the increase in fetal heart weight and in wall thickness resulting from maternal cortisol infusion. In the current study we extended those studies and found that cortisol increased Ki67 staining in both ventricles, indicating cell proliferation, but also increased active caspase-3 staining in cells of the conduction pathway in the septum and subendocardial layers of the left ventricle, suggesting increased apoptosis in Purkinje fibers. The MR antagonist blocked the increase in cell proliferation, whereas the GR antagonist blocked the increased apoptosis in Purkinje fibers. We also found evidence of activation of caspase-3 in c-kit positive cells, suggesting apoptosis in stem cell populations in the ventricle. These studies suggest a potentially important role of corticosteroids in the terminal remodeling of the late gestation fetal heart, and suggest a mechanism for the cardiac enlargement with excess corticosteroid exposure.
... Reactions were carried out using 20 ng of cDNA template. Probes and primers used in the analysis are previously published sequences: GHR (Bloomfield et al. 2006), glucocorticoid receptor (GR) (Keller- , IGF-I (Meinel et al. 2003), IGF-II, IGF-1R and IGF-2R (Reini et al. 2006), IGF-BP1, -BP2 and -BP3 (Shaikh et al. 2005), and β-actin (Keller- Wood et al. 2009). All samples were run in triplicate; all samples for each gene from all three experimental groups were analyzed on the same PCR plate. ...
Maternal cortisol levels increase during pregnancy. Although this change is important for optimal fetal growth, the mechanisms of the changes in growth remain unclear. The hypothesis examined was that alterations in maternal plasma cortisol concentrations are associated with changes in the fetal insulin-like growth factor (IGF) axis. Pregnant ewes in late gestation (115 ± 0.4 days) were studied: six control animals, five ewes given 1 mg kg(-1) day(-1) cortisol (high cortisol) and five adrenalectomised ewes given 0.5-0.6 mg kg(-1) day(-1) cortisol (low cortisol). Blood samples were taken throughout the experiment and at necropsy (130 ± 0.2 days) and fetal liver was frozen for mRNA analysis. Fetal IGF-I and insulin plasma concentrations were lower and insulin-like growth factor-binding protein-1 (IGFBP-1) concentrations were higher in the low cortisol group compared with those in the control group (P < 0.05). Fetal liver IGF-II and IGFBP-3 mRNA were decreased in low cortisol animals compared with controls (P < 0.05). There were no significant changes in these parameters in the high cortisol group, and there were no changes in fetal liver IGF-I, growth hormone receptor, IGF-I receptor, IGF-II receptor, IGFBP-1 or IGFBP-2 mRNA levels between the groups. These data suggest that reduced fetal IGF availability contributes to reduced fetal growth when maternal cortisol secretion is impaired, but not during exposure to moderate increases in cortisol.
... Reactions were carried out using cDNA template (20 or 100 ng). Probes and primers used in the analysis are previously published sequences: IGF-I [16], IGF-II, insulin-like growth factor-I receptor (IGF-IR) and IGF-IIR [17], insulinlike growth factor binding protein-1 (IGF-BP1), -BP2 and -BP3 [18], MR and GR [19], AT1R, AT2R, 11β-HSD1 and 2 [20], and β-actin [21]. All samples were run in triplicate with samples from all three experimental groups run on the same plate. ...
... We did not find any change in the expression of AT1R in the placenta with maternal cortisol treatment. Previous studies in other fetal organs have found a decrease in gene expression of AT1R in the kidney and liver and an increase [29] or decrease [17] in the heart as a result of cortisol treatment. We found that there was a significant increase in the ratio of AT2 to AT1 receptor expression in the B and C type cotyledons compared with A types, independent of treatment group. ...
The aim of this study was to investigate the effect of cortisol on growth-related genes in the ovine placenta.
Ewes carrying singleton pregnancies were operated on between 112 and 116 days of gestation (115 ± 0.4, term = 147 days) and randomly assigned into three groups: six control animals, five ewes that were administered cortisol by continuous intravenous infusion (1 mg/kg/day, high cortisol), and five ewes that were adrenalectomized and replaced with 0.5-0.6 mg cortisol/kg/day and 3 μg aldosterone/kg/day to produce cortisol concentrations equivalent to pre-pregnancy values (low cortisol). At necropsy (130 ± 0.2 days of gestation), placental tissue was frozen and stored at -80 °C for mRNA analysis.
To assess potential molecular mechanisms by which cortisol alters placental structure and function and fetal growth.
Cortisol levels did not significantly affect 11β-hydroxysteroid dehydrogenase 1 and 2 enzymes, glucocorticoid receptor, mineralocorticoid receptor and angiotensin II receptor, type 1 (AT1R) expression levels. Gene expression levels of AT2R were increased in the high cortisol group for type B placentomes. There was little effect of cortisol on the insulin-like growth factor (IGF) axis. There was significantly more IGF-I mRNA in B versus A type and more IGFBP-2 mRNA in B and C type versus A type placentomes regardless of treatment (p < 0.05).
These data suggest that cortisol increases placental AT2R expression at high concentrations whereas it has little effect on the placental IGF axis.
... This study indicates that changes in the expression of mRNAs related to angiotensin activity correspond to changes in proliferative activity and differentiation in the maturing heart. Angiotensin has been implicated in fetal cardiac growth (Reini and S.A., 2006;Segar et al., 2001), hyperplasia of fetal cardiomyocytes (Sundgren et al., 2003b), and in cardiac hypertrophy in response to increased blood pressure in the fetus (Lumbers et al., 2005). In the adult heart, the local production of angiotensin has been implicated in playing a major role in cardiac hypertrophy and fibrosis (Xu et al., 2007). ...
... The same genes were studied in RNA from RV except for IGFBP3. Probe and primer sequences were based on previously published sequences: MR and GR , IGF-I (Meinel et al., 2003), angiotensinogen (Burrell et al., 2003), 11βHSD2, AT1R and AT2R (Dodic et al., 2002), IGFBP2 and IGFBP3 (Bloomfield et al., 2006), and for 11βHSD1, IGF-II, IGF-1R, IGF-2R, ACE1 and ACE2 (Reini and S.A., 2006). For ACE1 and ACE2, SYBR Green (Bio-Rad) was used instead of Taqman probes (FAM-TAMRA purchased from Applied Biosystems). ...
The objective of this study was to determine the ontogenetic profiles in left and right ventricle of genes implicated in cardiac growth, including mineralocorticoid (MR) and glucocorticoid (GR) receptor, 11 beta-hydroxysteroid dehydrogenase (11β-HSD) 1 and 2 and genes of the angiotensin system and insulin-like growth factor (IGF) family. Samples from left and right ventricles (LV, RV) were collected from hearts of sheep fetuses at 80, 100, 120, 130, and 145 days of gestation and from newborn lambs. Quantitative real-time PCR was performed to determine the MR, GR, 11β-HSD 1 and 2, angiotensin converting enzyme (ACE) 1 and 2, IGF1, IGF2, IGF receptors IGF-1R and IGF-2R, and IGF-binding proteins (IGFBP) 2 and 3. In the LV, MR and GR both decreased toward term. In the RV, MR and GR expression did not decrease, but both 11β-HSD 1 and 2 mRNA levels increased after birth. ACE1 expression in LV and RV sharply increases just before parturition, whereas ACE2 decreased in the LV and RV in late gestation. IGF2, IGF2R, and IGFBP2 expression levels substantially decreased in late gestation in LV and RV; IGF2R also decreased with age in LV. These patterns suggest that reduced expression of genes related to IGF and angiotensin II action occur as proliferative activity declines and terminal differentiation occurs in the late gestation fetal heart.
... We have shown that maternal cortisol infusion in sheep during late gestation caused an increase in fetal heart size and wall thickness without increasing fetal arterial pressure or cardiac angiotensinogen; we found an increase in the ratio of angiotensin type 2 receptor (AT2 receptor) to angiotensin type 1 receptor (AT1 receptor) mRNA in the fetal heart, suggesting that the renin-angiotensin system (RAS) may play a key role in the enlargement process. Furthermore, in the same study it was observed that left ventricular expression of 11 -HSD2 mRNA, the enzyme that converts cortisol into cortisone, decreased in the fetal hearts in response to the elevated cortisol, suggesting that cortisol can act directly on Page 3 of 33 mineralocorticoid (MR) or glucocorticoid (GR) receptors to induce the cardiac enlargement (Reini et al. 2006). ...
... Hearts were dehydrated with increasing concentrations of reagent alcohol followed by xylene, embedded in paraffin wax, cut into 10-µm-thick sections on a Zeiss rotary microtome, and placed on poly-l-lysine coated slides. The sections were stained with anti-GR (Santa Cruz Bioreagents, M-20, ) or anti-MR ( M1-18, 6G1, gift of E. Gomez-Sanchez; (Gomez-Sanchez et al. 2006)) as previously described (Reini et al. 2006) This analysis was performed to assess the ability of the drugs to act in the heart and cause the expected changes in cytonuclear localization of the receptors. The MR antagonist canrenoate acts in a similar manner to spironolactone and would therefore be expected to prevent nuclear localization of MR (Fejes-Toth et al. 1998;Lombes et al. 1994); conversely the GR antagonist mifepristone (also known as RU486) causes nuclear localization even in the absence of agonist (Jewell et al. 1995;Scheuer et al. 2004). ...
... Our laboratory has previously shown that both MR and GR are abundantly expressed in the heart in the late gestation ovine fetus (Reini et al. 2006), suggesting a role for these receptors in fetal heart development in vivo. Other investigators have found that aldosterone directly stimulates myocyte surface area (Okoshi et al. 2004) and remodeling of myocyte membrane (Kliche et al. 2006) in cultures of neonatal myocytes, and effect presumed to be mediated by MR in the myocytes. ...
Previous studies have demonstrated that modest, physiologically relevant increases in maternal cortisol in late gestation result in enlargement of the fetal heart. In this study, we investigated the role of mineralocorticoid receptor (MR) or glucocorticoid receptor (GR) in this enlargement. Ewes with single fetuses were randomly assigned at approximately 120 days of gestation to one of four groups: maternal cortisol infusion (1 mg/kg per day, cortisol); maternal cortisol infusion with fetal intrapericardial infusion of the MR antagonist (MRa) potassium canrenoate (600 microg/day; cortisol+MRa); maternal cortisol infusion with fetal intrapericardial infusion of the GR antagonist (GRa) mifepristone (50 microg/day, cortisol+GRa); and maternal saline infusion (control). At approximately 130 days of gestation, fetal heart to body weight ratio and right ventricular (RV) and left ventricular (LV) free wall thicknesses were increased in the cortisol group when compared with control group. Fetal hearts from the cortisol+MRa group weighed significantly less, with thinner LV, RV, and interventricular septum walls, when compared with the cortisol group. Fetal hearts from the cortisol+GRa group had significantly thinner RV walls than the cortisol group. Fetal arterial pressure and heart rate were not different among groups at 130 days. Picrosirius red staining of fetal hearts indicated that the increased size was not accompanied by cardiac fibrosis. These results suggest that physiologic increases in maternal cortisol in late gestation induce fetal cardiac enlargement via MR and, to a lesser extent, by GR, and indicate that the enlargement is not secondary to an increase in fetal blood pressure or an increase in fibrosis within the fetal heart.
... In epithelial tissue, corticosterone is converted into cortisone, which is inactive at MR, by 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) (46). However, in cardiac myocytes 11β-HSD2 is not appreciably expressed (47,48). In this regard, it is noteworthy that corticosterone could bind MR in our experimental protocol. ...
The roles of aldosterone in the progression of heart failure have not been fully elucidated. This study examined whether aldosterone nongenomically activates reactive oxygen species (ROS) production, causing myocyte apoptosis. Addition of aldosterone to neonatal rat cardiac myocytes caused the activation of NADPH oxidase and intracellular ROS production in a dose-dependent manner (10-(9)-10(-7) mol/L). NADPH oxidase activation was evident as soon as 5 min after aldosterone treatment. Neither an inhibitor for nuclear transcription (actinomycin D) nor an inhibitor of new protein synthesis (cycloheximide) blocked this rapid activation, and specific binding of aldosterone to plasma membrane fraction was inhibited by eplerenone, suggesting a nongenomic mechanism. Aldosterone did not affect the mRNA or protein levels of NOX2, which is a major subunit of NADPH oxidase in myocytes, after 48 h. Nuclear staining with DAPI showed that aldosterone (10(-7) mol/L) increased the myocyte apoptosis (2.3 fold, p<0.001), coincident with the activation of caspase-3 (1.4 fold, p<0.05), compared with the serum-deprived control after 48 h. Aldosterone also induced phosphorylation of apoptosis signal-regulating kinase 1 (ASK1). These effects of aldosterone on myocyte ROS accumulation, ASK1 activation, and apoptosis were abolished by eplerenone, a mineralocorticoid receptor (MR) antagonist, apocynin, an inhibitor of NADPH oxidase activation, and tempol, a free radical scavenger, but by neither RU486, a glucocorticoid receptor antagonist, nor butylated hydroxyanisol (BHA), a mitochondrial ROS scavenger. In conclusion, aldosterone-mediated ROS production is blocked by eplerenone and induced by the nongenomic activation of NADPH oxidase, leading to myocyte apoptosis associated with ASK1 activation. These proapoptotic actions of aldosterone may play a role in the progression of heart failure.
