Administration Of Spironolactone Research Articles

Spironolactone (Sp) reduces renal dysfunction and structural damage in established chronic cyclosporine (CsA) nephrotoxicity.

Recent studies from our laboratory showed that the mineralocorticoid receptor blockade with Sp reduced renal injury and reestablished renal dysfunction in both, acute and chronic CsA nephrotoxicity. This study was design to evaluate if spironolactone administration reduces or prevents functional and structural renal damage in established chronic CsA nephrotoxicity. Wistar male rats were fed whit low sodium diet, twenty received vehicle (V) and twenty were treated with CsA (15mg/K sc), after 18 days one half of each group received Sp (20 mg/K p.o.) by 18 days more. Creatinine clearance, arteriolopathy, tubulo-interstitial fibrosis, TGFβ and kidney injury molecule 1 (KIM-1) mRNA levels, as well as KIM-1 in urine were evaluated. Sp reduced renal dysfunction progression and renal structural damage. These effects were associated with reduction of TGFβ and KIM-1 mRNA levels as well as urinary KIM-1. All our findings together showed that the early Sp administration confers greater renoprotection that when it is administrated once the nephropathy is established. These results also pointed out to spironolactone as a potential treatment to prevent or reduce CsA nephrotoxicity in transplant patients.

Combination Therapy with Aldosterone Blockade and Renin-Angiotensin Inhibitors Confers Organ Protection

There is increasing evidence that aldosterone exerts major adverse cardiovascular effects through classical mineralocorticoid receptors (MR) in nonepithelial tissues such as the brain and heart. This nonepithelial role of aldosterone has been underscored by the recent Randomized Aldactone Evaluation Study (RALES) and the Eplerenone Post-AMI Heart Failure Efficacy and Survival Study (EPHESUS). These studies also showed that when using MR antagonist as an "organ protecting" drug, further organ protection could be derived by the addition of an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II type 1 receptor blocker (ARB). The long-term effect of aldosterone was not inhibited in some subjects, so the possibility of organ damage due to so-called "breakthrough" aldosterone cannot be ignored. Nonepithelial MR-mediated effects played a major role in this aldosterone effect. These effects can be inhibited by MR antagonist at a small dose, not lower blood pressure. Therefore, the idea is now to combine a small dose of MR antagonist with an ACE inhibitor or ARB. However, warnings have been given recently due to the emergence of hyperkalemia and other adverse effects associated with inappropriate combination therapy. It is important to note that, if the eligibility criteria of RALES and EPHESUS are fulfilled, the potassium level will rarely become problematic. Therefore, the recent increase in the incidence of adverse effects can be attributed to the incorrect application of combination therapy. Elderly patients or those with dehydration, renal dysfunction, and aggravated heart failure require further close monitoring or termination of spironolactone administration. The combination of an MR antagonist and renin-angiotensin inhibitors should be a useful strategy if subjects are carefully selected, and carefully monitored. Adverse effects will occur only if the usage recommendations based on previous researches are not followed.

Serum concentration of potassium in chronic heart failure patients administered spironolactone plus furosemide and either enalapril maleate, losartan potassium or candesartan cilexetil

To retrospectively investigate elevation of serum potassium when spironolactone (25 or 50 mg/day) and furosemide were administered concomitantly with an angiotensin II converting enzyme inhibitor (ACE-I) or angiotensin II receptor blocker (ARB) to patients with chronic heart failure for 12 months and occurrence of hyperkalemia and hypokalemia because of concomitant administration of spironolactone plus an ACE-I or ARB and furosemide. Patients with chronic heart failure, who visited departments of cardiovascular internal medicine and cardiovascular surgery at the National Hospital Organization Osaka Medical Center, were enrolled for this study. Serum potassium, blood urea nitrogen (BUN), serum creatinine, uric acid, and serum sodium were determined in every patient at the time of start of treatment and at 3 and 12 months of treatment. Data from patients in Groups A (25 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) and B (50 mg/day spironolactone + 40 mg/day furosemide + an ACE-I or ARB) were analysed for differences with respect to the ACE-I and ARB used. When 50 mg/day spironolactone plus 5 mg/day enalapril maleate (enalapril) or 50 mg/day losartan potassium (losartan) or 8 mg/day candesartan cilexetil (candesartan) plus 40 mg/day furosemide were concomitantly used, the mean value of serum potassium was significantly elevated only in the group treated with 50 mg/day spironolactone regardless of the concomitant drug. The number of patients with hyperkalemia (>5.5 mEq/L) at 12 months of treatment was 12 (8.8%), while the number of patients with hypokalemia (<or=3.5 mEq/L) was 7 (5.1%). However, the occurrence of hyperkalemia was almost the same regardless of the dose of spironolactone or the ACE-I or ARB concomitantly administered. Therefore, if enalapril, losartan, or candesartan is concomitantly used, it is necessary to monitor the serum concentration of potassium, even if spironolactone is administered at a dose of 25 mg/day. The occurrence of hyperkalemia in patients administered spironolactone is influenced by the dose, but when it is used concomitantly with enalapril, losartan or candesartan, the occurrence of hyperkalemia exceeding 5.5 mEq/L may increase even if the dose of spironolactone is as low as 25 mg. Thus it is essential to always monitor serum potassium.

The hypothalamopituitary–adrenal axis and alcohol preference

Effects of alterations in stress hormones and their actions were investigated on alcohol preference, by intraperitoneal administration of RU38486 (a Type II glucocorticoid receptor antagonist, also given by the intracerebroventricular route), spironolactone (a Type I glucocorticoid receptor antagonist), metyrapone (a corticosterone synthesis inhibitor), corticosterone, adrenocorticotropin (ACTH1-39), or intracerebroventricular injection of corticotropin releasing factor (CRF) or a CRF antagonist (alpha-helical CRF9–41). Intracerebroventricular or intraperitoneal administration of RU38486 did not alter the alcohol consumption of mice with high preference for alcohol, or, on first administration, the intake of those with low alcohol preference. When given by repeated intraperitoneal injection however this drug prevented the increase in alcohol consumption seen in “low preference” mice after 3 weeks vehicle injections. Spironolactone did not alter alcohol preference when given by intracerebroventricular or intraperitoneal routes. Repeated, but not single, administration of metyrapone reduced alcohol preference in both high and low preference animals and prevented the increase from low alcohol preference caused by repeated vehicle injections. ACTH1–39 or corticosterone administered by single or repeated intraperitoneal injection, or CRF given i.c.v., did not alter alcohol preference, but the CRF antagonist, alpha-helical CRF9–41, caused a transient increase from low alcohol preference. Blood corticosterone concentrations prior to preference measurements did not correlate with the alcohol preference of the mice. The results indicate that delayed consequences of corticosterone acting on Type II glucocorticoid receptors may be involved in the increases in alcohol preference after injection stress. They also suggest that central actions of CRF may influence the low alcohol consumption of the low alcohol-preferring mice.

Pharmacology Review

After completing this article, readers should be able to: 1. Review the actions of the diuretic agents commonly used in neonates. 2. Delineate the adverse effects of diuretic therapy. 3. Determine the roles of diuretics in therapy. Diuretics represent one of the most common classes of drugs administered to sick neonates and infants. Unwanted fluid retention arising from myriad neonatal disorders can and does complicate the optimal care of sick infants. To appreciate the many factors that influence a patient’s response to diuretic therapy and clinical and laboratory monitoring, we direct readers to the article “The Ontogeny of Human Kidney Development: Influence on Neonatal Diuretic Therapy” in this issue. All the clinically relevant diuretics, with the exception of aldosterone receptor antagonists (eg, spironolactone), must achieve sufficient free drug concentrations within the renal tubular lumen to reach their sites of action. Thus, diuretic effectiveness ultimately is guided by the functional capacity of the kidney, which clearly is influenced by infants’ gestational and postnatal ages. This article addresses the most common diuretics used in the neonate and young infant, focusing on the pharmacokinetic and pharmacodynamic characteristics of each drug relative to the infant’s postconceptional age and other factors that influence the infant’s overall response to therapy. ### “Loop” or “High Ceiling” Diuretics All diuretics, with the exception of spironolactone, must reach the renal tubular lumen to exert their pharmacologic effect. A lower renal blood flow (RBF) in preterm infants reduces the amount of drug delivered to the kidney, potentially limiting diuretic effectiveness. Highly protein-bound, loop diuretics (Table 1) are filtered minimally at the glomerulus. Instead, these agents are carried to the proximal tubule where they are actively secreted into the lumen via the organic acid transport pump. Luminal flow then carries the loop diuretics to their sites of action. | Loop Diuretics | || | •Bumetanide | | •Furosemide | | •Torsemide | | Thiazide Diuretics | | •Chlorothiazide | | •Chlorthalidone | | •Hydrochlorothiazide | | •Indapamide | | •Metolazone | | Aldosterone Antagonists | | •Eplerenone | | •Spironolactone | Table 1. Commonly Used Diuretic Drugs in Preterm and Newborn Infants Loop diuretics bind …

Effect of Spironolactone on Blood Pressure and the Renin-Angiotensin-Aldosterone System in Oligo-Anuric Hemodialysis Patients

Through its actions on nonepithelial tissues, including brain, blood vessels, and heart, aldosterone may mediate hypertension, cardiac hypertrophy, and fibrosis. Whether aldosterone has a direct pathogenic role in the development of cardiovascular complications in patients with end-stage renal disease is unknown. Oligo-anuric dialysis patients provide a clinical setting to study the effects of the mineralocorticoid receptor blocker spironolactone that are independent of the diuretic properties of the drug. We performed a randomized, double-blinded, placebo-controlled, crossover study to assess the effect of spironolactone on blood pressure and the renin-angiotensin-aldosterone system in oligo-anuric hemodialysis patients. Eight hemodialysis patients were administered either spironolactone, 50 mg, or placebo orally twice daily for 2 weeks, followed by a 3-week washout period, after which patients crossed over in their treatment arms for 2 more weeks. Administration of spironolactone for 2 weeks decreased predialysis systolic blood pressure from 142.0 +/- 19.6 to 131.4 +/- 18.2 mm Hg (P < 0.05). Compared with placebo, a 2-week course of spironolactone had no effect on predialysis and postdialysis plasma potassium or aldosterone concentrations or renin activity. When administered for 2 weeks, spironolactone, 50 mg twice daily, reduced predialysis systolic blood pressure, but did not produce hyperkalemia in oligo-anuric hemodialysis patients.

Aldosterone induces myocyte apoptosis in the heart and skeletal muscles of rats in vivo

Over activation of the renin–angiotensin–aldosterone system is known to be cardiotoxic but the potential injurious effects on the skeletal musculature have not been investigated. Male Wistar rats were given subcutaneous injections of aldosterone (1 μg–10 mg kg –1) and killed 7 h later, or continuous infusion (1 mg kg –1 d –1) and killed 48 h later. The role of the mineralocorticoid receptor in mediating aldosterone-induced apoptosis in vivo was investigated using spironolactone (200 mg kg –1). The number of apoptotic (caspase 3 positive) myocytes was counted on cryosections of the heart, soleus and Tibialis Anterior muscles. Injections of aldosterone induced significant ( P < 0.05) cardiomyocyte apoptosis (peak = 2.46 ± 0.6 per 10 4 viable myocytes) over the range of 100 μg–10 mg kg –1, whereas only administration of 1 mg kg –1 induced significant ( P < 0.05) apoptosis (2.47 ± 0.8 per 10 4 viable myocytes) in the soleus muscle. In contrast, no apoptosis was detected in the striated muscles after administration of only the vehicle. Infusion of aldosterone induced less apoptosis than the same dose (1 mg kg –1) given as a single injection. Prior administration of spironolactone significantly ( P < 0.05) protected the heart (90%) and soleus muscle (79%) against the apoptosis induced by a single injection of 1 mg kg –1 aldosterone. These data confirm a myotoxic effect of aldosterone on the heart and provide the first description of aldosterone-induced myocyte apoptosis in skeletal muscle. High circulating levels of aldosterone are clearly capable of damaging all types of striated muscle and this may lend support to the concept that heart failure is a generalised, rather than cardiac-specific, myopathy.

The effect of spironolactone on experimental periodontitis in rats

Elevated levels of tumour necrosis factor (TNF) have been found in patients with adult periodontitis. Animal studies have shown that TNF plays an important role in the pathogenesis of periodontitis. New findings suggest that the aldosterone-inhibitor spironolactone possesses an anti-TNF effect. The purpose of the study was to determine the anti-TNF effect of spironolactone in an endotoxic shock rat model and to disclose the effect of oral administration of spironolactone on the development of experimental periodontitis in rats. The study was divided in two parts. Part 1: oral administration of spironolactone (100 mg/kg) followed by intravenous lipopolysaccharide (1 mg/kg) infusion 45 min later. Blood samples were taken before and 90 min after lipopolysaccharide infusion to determine the TNF levels in spironolactone treated and non-treated rats. Part 2: oral administration of spironolactone [100 mg/(kg day)] starting 2 days prior to induction of experimental periodontitis established by peridental ligatures. Morphometrical and radiographical registrations of alveolar bone destruction were carried out to determine the effect of spironolactone on the progression of experimental periodontitis. In part 1 the endotoxic shock model showed a significant reduction in TNF levels in the spironolactone-treated group compared to the non-treated group, suggesting that spironolactone acts as a TNF inhibitor. In part 2 spironolactone-treated rats did not demonstrate significantly less alveolar bone destruction compared to non-treated rats. The insignificant effect of spironolactone treatment could be explained by the fast metabolism of spironolactone and that spironolactone does not completely inhibit TNF production in rats. Moreover, many other cytokines and mediators involved in alveolar bone destruction may account for the lacking response to spironolactone.

Aldosterone does not mediate angiotensin II‐induced atherosclerosis and abdominal aortic aneurysms

We have demonstrated previously that infusion of angiotensin II (AngII) into hyperlipidemic mice augments atherosclerosis and results in the formation of abdominal aortic aneurysms (AAA). The purpose of this study was to determine the role of aldosterone in these AngII-induced vascular pathologies. Male apolipoprotein E-/- (apoE) mice were infused with either vehicle or aldosterone (50 or 200 ng kg(-1) min(-1)). Arterial blood pressure was determined throughout the study and serum lipid concentrations and vascular pathology were quantified after 28 days of infusion. Infusion of aldosterone did not influence body weight or serum cholesterol concentrations. Kidney weight was increased dose-dependently by aldosterone infusion. Systolic blood pressure was not significantly altered by aldosterone. Plasma aldosterone concentrations were increased dose-dependently by infusion of aldosterone. However, there was no effect of aldosterone on the extent of atherosclerosis and AAAs were not formed. Implantation of pellets containing spironolactone (16 mg kg(-1) day(-1)) in AngII-infused apoE-/- mice (1000 ng kg(-1) min(-1)) had no effect on AngII-induced elevations in blood pressure. Plasma aldosterone concentration was not influenced by coadministration of spironolactone with AngII. Spironolactone administration did not influence the extent of atherosclerosis. Moreover, spironolactone had no significant effect on AngII-induced AAA (incidence of AAA formation: 80 versus 70% for vehicle versus spironolactone, respectively; not significant). These studies demonstrate that the AngII-induced vascular pathologies of atherosclerosis and AAA formation are not mediated through aldosterone.

Ga-67 Citrate and F-18 FDG Uptake in Spironolactone-Induced Gynecomastia

We evaluated a male patient with chronic heart failure using Ga-67 citrate and F-18 FDG imaging to eliminate secondary dilated cardiomyopathy resulting from sarcoidosis. Tracer accumulated bilaterally in the breast tissueduring both imaging procedures. This uptake was probably the result of bilateral gynecomastia caused by therapeutic spironolactone administration in addition to standard therapy for chronic heart failure.

A Case of Gitelman's Syndrome with Short Stature

We report the case of an 8-yr-old girl with short stature. Her height was -2.65 SD and blood examination revealed hypokalemia (2.9 mEq/l), hypomagnesaemia, hypocalsiuria (Ca/Cr=0.0039) and metabolic alkalosis (pH 7.454, HCO3- 24.9 mmol/l). For differential diagnosis between Gitelman's syndrome (GS) and Bartter syndrome (BS), we performed the loop diuretic furosemide (FUR) test and hydrochlorothiazide (HCT) double dose (2 and 4 mg/kg) test. Even the higher dose of HCT induced significantly lower increase of urinary Na and Cl excretions than the FUR. Growth hormone (GH) secretion tests (insulin and arginine) revealed GH deficiency. In addition to growth hormone injection, administration of Mg and spironolactone was started. After the replacement therapy started, the girl's height gain was improved (9.7 cm/yr) and her serum potassium became within the reference range. One year after GH replacement therapy was performed and GH replacement therapy was discontinued for two months, and GH secretion tests (insulin and arginine) showed GH deficiency again. We discussed previous reports of the clinical signs and test results of GS with regard to the relation between hypokalemia, hypomagnesemia and short stature.

Long-Term Effect of Spironolactone on Cardiac Structure as Assessed by Analysis of Ultrasonic Radio-Frequency Signals in Patients With Ventricular Hypertrophy

An effect of aldosterone on ventricular fibrosis has been demonstrated in animals, but remains unclear in human patients. This study aimed to investigate (1) the relationship between left ventricular (LV) fibrosis and myocardial ultrasonic texture as assessed with myocardial radio-frequency (RF) signals analyzed from the viewpoint of their waveform with chaos theory in animals and (2) serial changes in myocardial ultrasonic texture following long-term aldosterone blockade in patients with LV hypertrophy. In an animal study, Sprague-Dawley rats were divided into 2 groups with and without adriamycin administration, and the relationship between the RF signals and LV fibrosis was assessed. In a clinical study, effects of 12-month-administration of spironolactone were assessed in patients with LV hypertrophy. The animal study revealed that the correlation dimension (CD) calculated from the RF signals inversely correlated with the area of fibrosis. The clinical study demonstrated an increase in CD following 6-month administration of spironolactone. The changes in CD positively correlated with those in the serum carboxy-terminal telopeptide of collagen type I. Myocardial RF signals analyzed with chaos theory reflect the severity of LV fibrosis. Aldosterone blockade may alter myocardial ultrasonic texture with regression of LV fibrosis, at least partly through enhanced collagen degradation.

Critical role of CNS effects of aldosterone in cardiac remodeling post-myocardial infarction in rats

Oral administration of spironolactone improves cardiac remodeling and its central infusion prevents the increase in sympathetic drive post-myocardial infarction (MI). We hypothesized that central actions of aldosterone contribute to cardiac remodeling post-MI. To compare the effects of intracerebroventricular (icv) infusion and oral administration of spironolactone on cardiac remodeling and left ventricle (LV) dysfunction post-MI in rats. Spironolactone was administered orally (80 mg/kg/day) or by icv infusion (100 ng/h), starting 1-3 days post-MI in Wistar rats and continued for 6 weeks. At 6 weeks post-MI, in the rats treated with vehicle, LV peak systolic pressure (LVPSP) and LV dP/dt max were clearly decreased and LV end diastolic pressure (LVEDP) and plasma catecholamines and serum aldosterone increased. All these parameters improved with both oral and icv spironolactone. The MI-induced increases in internal circumferences of LV and right ventricle (RV), and in interstitial and perivascular fibrosis, in both the LV and RV were significantly prevented/inhibited by both oral and icv spironolactone. Laminin, fibronectin and fibrillar collagen (visualized by scanning electron microscopy, SEM) increased in the non-infarcted part of the LV post-MI in the vehicle group, but not/less in rats on oral or icv spironolactone. Since the magnitude of beneficial effects of icv spironolactone at low doses was largely equal to that achieved with its oral administration at much higher doses, we propose that in addition to other sites of action, aldosterone appears to activate central nervous system (CNS) pathways and thereby influences peripheral mechanisms involved in cardiac remodeling.

Spironolactone Does Not Prevent Restenosis After Coronary Stenting in Humans

Introduction: In animal studies, aldosterone enhanced neointimal proliferation by increasing extracellular accumulation of collagen and potentiating the effects of angiotensin II. Spironolactone, an aldosterone antagonist, is a potent inhibitor of neointimal proliferation. We conducted a placebo-controlled, double-blind, randomised study to assess the effect of spironolactone on angiographic 6-month in-stent restenosis. Materials and Methods: Of the 310 randomised patients with significant coronary artery disease, 258 patients were available for analysis: 128 constituted the placebo group and 130 were assigned to receive spironolactone. Eligible patients were randomly assigned to receive a dose of 50 mg spironolactone or placebo orally twice a day for 6 months. The primary endpoint was the angiographic restenosis (&gt;50% stenosis) rate at follow-up angiography. Results: At 6-month follow-up angiography after stenting, there was no difference between the 2 groups in minimal lumen diameter, percent diameter stenosis, late loss, and net gain. Angiographic restenosis occurred in 46 (35.4%) of 130 patients receiving spironolactone and 50 (39.0%) of 128 in the placebo group with an odds ratio (OR) of 0.85 with a 95% confidence interval (CI) of 0.49 to 1.46 (P = 0.62). Restenosis rate was found in 60 (32.9%) of 182 lesions in the spironolactone group, and 61 (35.5%) of 172 lesions in the placebo group with an OR of 0.89 with a 95% CI of 0.56 to 1.42 (P = 0.89). Conclusions: Spironolactone did not reduce the incidence of in-stent restenosis as compared with placebo in human, contrary to the fact that reduction of neointimal formation in animal models has been observed upon administration of spironolactone.

PREVENTION OF RENAL FIBROSIS BY SPIRONOLACTONE IN MICE WITH COMPLETE UNILATERAL URETERAL OBSTRUCTION

Recent data suggest that aldosterone directly mediates cardiac fibrosis and hypertensive nephrosclerosis. We conducted experiments to determine whether administration of spironolactone, a mineralocorticoid receptor antagonist, reduced renal fibrosis in an experimental model of obstructive uropathy. Complete unilateral ureteral obstruction (UUO) was created surgically in 8 to 10-week-old male C57BL/6 mice by placing sutures around the right ureter. Spironolactone (50 mg/kg/daily) or 1% dimethyl sulfoxide vehicle was administered by subcutaneous injection for 1 to 2 weeks, and renal fibrosis was assessed by measuring trichrome staining and type I collagen deposition in the kidney. UUO lasting 1 week was associated with minimal parenchymal damage and spironolactone had no demonstrable effect. In contrast, administration of the mineralocorticoid antagonist (8 mice) for a 2-week period significantly reduced renal fibrosis in the obstructed kidney, compared to mice given the dimethyl sulfoxide vehicle (9). The beneficial effect of spironolactone treatment was not associated with any changes in serum potassium or aldosterone concentration, or urinary concentrations of sodium or potassium. Administration of spironolactone reduced renal fibrosis in mice with UUO. These findings suggest that clinical trials are warranted to determine the efficacy of aldosterone antagonists in conjunction with angiotensin converting enzyme inhibitors and/or angiotensin receptor blockers as renoprotective agents in patients with obstructive uropathy.

Aldosterone antagonists attenuate myocyte apoptosis and prevent ventricular remodeling in post-infarct rat hearts

Background: Aldosterone antagonists have been reported to prevent ventricular remodeling after myocardial infaction (MI) via its action to extracellular matrix (ECM). However, it remains largely unknown whether aldosterone antagonists directly attenuate myocyte loss in remodeling process. This study examined whether aldosterone antagonists prevent myocyte apoptosis and improve post-infarct ventricular remodeling. Methods and Results: MI was achieved by permanent occlusion of left coronary artery. Administration of spironolactone (Sp: 100mg/kg/day) was started on the first day after MI. Sprague-Dawley rats were divided into four groups; 1)Sham group, 2)Sham+Sp group, 3)MI group, 4)MI+ Sp group. Systolic BP was not significantly different among 4 groups. Echocardiographic parameters (LVDd, %FS) were not significantly different between MI group and MI+Sp group on the 2nd and 7th day. In contrast, echocardiographic parameters, hemodynamic parameters (+dp/dt, -dp/dt, LVEDP),and collagen accumulation quantitated by Masson's Trichrome staining were significantly improved in MI+ Sp group on the 14th day, compared to MI group. Moreover, the percentage of myocyte apoptosis evaluated by TUNEL assay was significantly decreased in MI+Sp group on the 2nd and 7th days, compared to MI group. Conclusions: The present study demonstrates that, in addition to the effect on ECM, early administration of aldosterone antagonists can inhibit myocyte apoptosis and prevent post-infarct ventricular remodeling, which may account for the important clinical efficacy of aldosterone antagonists against acute MI.

Early administration of either spironolactone or eprosartan reduces cardiac hypertrophy and fibrosis in rats with heart failure: possible involvement of ace and ace-2

P-140 Key Words: Aldosterone, Angiotensin II, Cardiac Hypertrophy

Human endothelium: target for aldosterone.

Aldosterone has long been known to control water and electrolyte balance by acting on mineralocorticoid receptors in kidney. However, recent studies demonstrated the presence of these receptors in nonclassical locations, including the cardiovascular system. We tested the hypothesis whether endothelial cells respond to aldosterone with changes in cell volume, a measure for ion-mediated water movement across the cell membrane. By means of atomic force microscopy in fluid, we measured volume of adherent human umbilical venous endothelial cells exposed for 72 hours to 10 nmol/L aldosterone. Over this period of time, cells swell by approximately 18%. Aldosterone-induced swelling is prevented by 100 nmol/L of the mineralocorticoid receptor antagonist spironolactone, added to the primary endothelial cell culture. Aldosterone-treated cells dramatically shrink when 1 micromol/L of the diuretic amiloride is applied. Cells deprived of aldosterone do not respond to amiloride. Our conclusions are: (1) aldosterone leads to sustained cell swelling inhibited by administration of spironolactone or the sodium channel blocker amiloride; (2) cells respond to amiloride after aldosterone exposure; (3) renal diuretics act on endothelial cells; and (4) both amiloride and spironolactone could be useful for medical applications to prevent aldosterone-mediated endothelial dysfunction.

Immediate administration of mineralocorticoid receptor antagonist spironolactone prevents post-infarct left ventricular remodeling associated with suppression of a marker of myocardial collagen synthesis in patients with first anterior acute myocardial infarction

Aldosterone has been shown to stimulate cardiac collagen synthesis and fibroblast proliferation via activation of local mineralocorticoid receptors. In patients with acute myocardial infarction, we demonstrated that aldosterone was extracted through the infarct-heart and extracting aldosterone stimulated post-infarct left ventricular remodeling.To evaluate the effect of mineralocorticoid receptor antagonist (MRA) spironolactone on post-infarct left ventricular remodeling. 134 patients with first anterior acute myocardial infarction were randomly divided into the MRA (n=65) or non MRA (n=69) group after revascularization. All patients were administrated angiotensin converting enzyme inhibitor (ACEI) and study drug just after revascularization. Left ventriculography with contrast medium was performed at acute and after 1 month to evaluate left ventricular remodeling. Aldosterone was measured at aortic root and coronary sinus. There was no difference in the baseline characteristics including infarct size and left ventricular performance between the two groups. However, left ventricular ejection fraction was significantly improved in MRA group compared with that in non MRA group (46.0 +/- 0.6% to 53.2 +/- 0.8% vs 46.5 +/- 0.8% to 51.0 +/- 0.8%, P interaction = 0.012). Left ventricular end-diastolic volume index was significantly suppressed in MRA group compared with that in non-MRA group (86.5 +/- 1.0 to 90.6 +/- 2.4 vs 87.5 +/- 1.3 to 106.8 +/- 3.5 ml/m2, P interaction = 0.002). Transcardiac extraction of aldosterone through the heart was significantly suppressed in MRA group (P interaction = 0.001) and plasma procollagen type III aminoterminal peptide, a biochemical marker of fibrosis, level was significant lower in MRA group compared with those in non-MRA group (P interaction + 0.002).These findings indicate that MRA combined with ACEI can prevent post-infarct left ventricular remodeling better than ACEI alone in association with the suppression of a marker collagen synthesis.

Therapeutic benefit of spironolactone in experimental chronic cyclosporine A nephrotoxicity

Cyclosporine A (CsA) is an immunosuppressive drug used to prevent tissue allograft rejection. However, its long-term utilization is limited due to chronic nephrotoxicity for which no prevention is available. This study evaluated the effect of spironolactone on renal functional and structural alterations induced by CsA, and assessed whether the protective effect was associated with a reduction of transforming growth factor-beta (TGF-beta) and the change of extracellular matrix protein mRNA level. Male Wistar rats fed with low sodium diet were divided in four treatment groups: vehicle, CsA (30 mg/kg), spironolactone (20 mg/kg), or CsA+spironolactone. After 21 days, creatinine clearance (CCr), blood CsA, arteriolopathy in renal tissue, and TGF-beta, collagen I, collagen IV, fibronectin, and epidermal growth factor (EGF) mRNA levels in renal cortex were determined. CsA reduced the CCr and up-regulated TGF-beta, collagen I and fibronectin mRNA expression with a significant development of arteriolopathy, and reduced EGF mRNA levels. In contrast, spironolactone administration prevented the fall in renal function and TGF-beta, collagen I, and fibronectin up-regulation, together with a reduction of arteriolopathy and tubulointerstitial fibrosis. Our data show that aldosterone plays an important role as a mediator of renal injury induced by CsA. Thus, mineralocorticoid receptor blockade may be a potential strategy to prevent CsA nephrotoxicity.