Spironolactone induces apoptosis and inhibits NF-kappaB independent of the mineralocorticoid receptor

Crosstalk between Aldosterone and Glycation through Rac-1 Induces Diabetic Nephropathy

Background: Advanced glycation end products (AGEs) interaction with its receptor (RAGE) and aldosterone (Aldo) through the mineralocorticoid receptor (MR) activates Rac-1 and NF-κB independently in diabetic nephropathy (DN). However, the crosstalk of Aldo with AGEs-RAGE is still unresolved. Our study examined the impact of the AGEs-Aldo complex on renal cells and its effect on the RAGE-MR interaction. Methods and results: Glycation of human serum albumin (HSA) (40 mg/mL) with methylglyoxal (10 mM) in the presence of Aldo (100 nM) and aminoguanidine (AG) (100 nM) was performed. Glycation markers such as fructosamine and carbonyl groups and fluorescence of AGEs, pentosidine, and tryptophan followed by protein modification were measured. Renal (HEK-293T) cells were treated with the glycated HSA-Aldo (200 μg/mL) along with FPS-ZM1 and spironolactone antagonists for RAGE and Aldo, respectively, for 24 h. Glycation markers and esRAGE levels were measured. Protein and mRNA levels of RAGE, MR, Rac-1, and NF-κB were estimated. Glycation markers were enhanced with Aldo when albumin was only 14-16% glycated. AGEs-Aldo complex upregulated RAGE, MR, Rac-1 and NF-κB expressions. However, FPS-ZM1 action might have activated the RAGE-independent pathway, further elevating MR, Rac-1, and NF-κB levels. Conclusion: Our study concluded that the presence of Aldo has a significant impact on glycation. In the presence of AGEs-Aldo, RAGE-MR crosstalk exerts inflammatory responses through Rac-1 in DN. Insights into this molecular interplay are crucial for developing novel therapeutic strategies to alleviate DN in the future.

Spironolactone Induces Apoptotic Cell Death in Human Glioblastoma U87-MG Cancer Cells

Background: Spironolactone is a conventional drug widely in use for the treatment of heart failure and hypertension patients. On the other side recent studies have reported spironolactone can prevent growth and drug resistance in cancer stem cells (CSCs), by inhibiting DNA double-strand break (DSB) repair; suggesting its potential application in cancer therapy. Objectives: Our study aimed at assessing the potential cytotoxicity of spironolactone in human U87-MG glioblastoma cells. Methods: Different concentrations of spironolactone (0 - 50 μM) for 48 and 72 h were used for treatment. Cell viability assay was carried out by the 4, 5-dimethylthiazole-2-yl, 2, 5-diphenyl tetrazolium (MTT) method. Apoptosis was evaluated using annexin V/PI staining and flow cytometry and colorimetric measurement of caspase 8 and 9 activity. Results: Our findings showed a significant dose-dependent cytotoxic effect of spironolactone with maximum effect in 30 μM (P-value < 0.05). Spironolactone can induce approximately 20% apoptotic cell death in U87-MG cancer cells which were mainly related to early apoptotic cells. Indeed, the activity of caspase 8 and 9 was significantly elevated in spironolactone-treated cells compared to mock control. Conclusions: Findings showed the cytotoxic effect of spironolactone in U87-MG glioblastoma cancer cells in a mechanism dependent on apoptosis cell death induction. Our findings suggest the potential application of spironolactone in the treatment of glioblastoma in vitro.

Topical Treatment of Human Skin and Cultured Keratinocytes with High-Dose Spironolactone Reduces XPB Expression and Induces Toxicity

Spironolactone (SP) is used to treat a variety of disparate disease states ranging from heart failure to acne through antagonism of the mineralocorticoid and androgen receptors. Although normally taken as an oral medication, recent studies have explored the topical application of SP onto the skin. However, because SP induces the proteolytic degradation of the XPB protein, which plays critical roles in DNA repair and transcription, there may be safety concerns with the use of topical SP. In this study, we show that the topical application of a high concentration of either SP or its metabolite canrenone onto human skin ex vivo lowers XPB protein levels and induces toxic responses in the epidermis. Interestingly, although SP and canrenone both inhibit cell proliferation, induce replication stress responses, and stimulate apoptotic signaling at high concentrations in cultured keratinocytes in vitro, these effects were not correlated with XPB protein loss. Thus, high concentrations of SP and canrenone likely inhibit cell proliferation and induce toxicity through additional mechanisms to XPB proteolytic degradation. This work suggests that care may need to be taken when using high concentrations of SP directly on human skin.

COVID-19-The Potential Beneficial Therapeutic Effects of Spironolactone during SARS-CoV-2 Infection

In March 2020, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 was declared a global pandemic by the World Health Organization (WHO). The clinical course of the disease is unpredictable but may lead to severe acute respiratory infection (SARI) and pneumonia leading to acute respiratory distress syndrome (ARDS). It has been shown that pulmonary fibrosis may be one of the major long-term complications of COVID-19. In animal models, the use of spironolactone was proven to be an important drug in the prevention of pulmonary fibrosis. Through its dual action as a mineralocorticoid receptor (MR) antagonist and an androgenic inhibitor, spironolactone can provide significant benefits concerning COVID-19 infection. The primary effect of spironolactone in reducing pulmonary edema may also be beneficial in COVID-19 ARDS. Spironolactone is a well-known, widely used and safe anti-hypertensive and antiandrogenic medication. It has potassium-sparing diuretic action by antagonizing mineralocorticoid receptors (MRs). Spironolactone and potassium canrenoate, exerting combined pleiotropic action, may provide a therapeutic benefit to patients with COVID-19 pneumonia through antiandrogen, MR blocking, antifibrotic and anti-hyperinflammatory action. It has been proposed that spironolactone may prevent acute lung injury in COVID-19 infection due to its pleiotropic effects with favorable renin–angiotensin–aldosterone system (RAAS) and ACE2 expression, reduction in transmembrane serine protease 2 (TMPRSS2) activity and antiandrogenic action, and therefore it may prove to act as additional protection for patients at highest risk of severe pneumonia. Future prospective clinical trials are warranted to evaluate its therapeutic potential.

A novel treatment for skin repair using a combination of spironolactone and vitamin D3

Injury of the skin from exposure to toxic chemicals leads to the release of inflammatory mediators and the recruitment of immune cells. Nitrogen mustard (NM) and other alkylating agents cause severe cutaneous damage for which there are limited treatment options. Here, we show that combined treatment of vitamin D3 (VD3) and spironolactone (SP), a mineralocorticoid receptor antagonist, significantly improves the resolution of inflammation and accelerates wound healing after NM exposure. SP enhanced the inhibitory effect of VD3 on nuclear factor-kB activity. Combined treatment of NM-exposed mice with VD3 and SP synergistically inhibited the expression of iNOS in the skin and decreased the expression of matrix metallopeptidase-9, C-C motif chemokine ligand 2, interleukin (IL)-1α, and IL-1β. The combined treatment decreased the number of local proinflammatory M1 macrophages resulting in an increase in the M2/M1 ratio in the wound microenvironment. Apoptosis was also decreased in the skin after combined treatment. Together, this creates a proresolution state, resulting in more rapid wound closure. Combined VD3 and SP treatment is effective in modulating the immune response and activating anti-inflammatory pathways in macrophages to facilitate tissue repair. Altogether, these data demonstrate that VD3 and SP may constitute an effective treatment regimen to improve wound healing after NM or other skin chemical injury.

Spironolactone-induced degradation of the TFIIH core complex XPB subunit suppresses NF-κB and AP-1 signalling

Aims

Spironolactone (SPL) improves endothelial dysfunction and survival in heart failure. Immune modulation, including poorly understood mineralocorticoid receptor (MR)-independent effects of SPL might contribute to these benefits and possibly be useful in other inflammatory cardiovascular diseases such as pulmonary arterial hypertension.

Methods and results

Using human embryonic kidney cells (HEK 293) expressing specific nuclear receptors, SPL suppressed NF-κB and AP-1 reporter activity independent of MR and other recognized nuclear receptor partners. NF-κB and AP-1 DNA binding were not affected by SPL and protein synthesis blockade did not interfere with SPL-induced suppression of inflammatory signalling. In contrast, proteasome blockade to inhibit degradation of xeroderma pigmentosum group B complementing protein (XPB), a subunit of the general transcription factor TFIIH, or XPB overexpression both prevented SPL-mediated suppression of inflammation. Similar to HEK 293 cells, a proteasome inhibitor blocked XPB loss and SPL suppression of AP-1 induced target genes in human pulmonary artery endothelial cells (PAECs). Unlike SPL, eplerenone (EPL) did not cause XPB degradation and failed to similarly suppress inflammatory signalling. SPL combined with siRNA XPB knockdown further reduced XPB protein levels and had the greatest effect on PAEC inflammatory gene transcription. Using chromatin-immunoprecipitation, PAEC target gene susceptibility to SPL was associated with low basal RNA polymerase II (RNAPII) occupancy and TNFα-induced RNAPII and XPB recruitment. XP patient-derived fibroblasts carrying an N-terminal but not C-terminal XPB mutations were insensitive to both SPL-mediated XPB degradation and TNFα-induced target gene suppression. Importantly, SPL treatment decreased whole lung XPB protein levels in a monocrotaline rat model of pulmonary hypertension and reduced inflammatory markers in an observational cohort of PAH patients.

Conclusion

SPL has important anti-inflammatory effects independent of aldosterone and MR, not shared with EPL. Drug-induced, proteasome-dependent XPB degradation may be a useful therapeutic approach in cardiovascular diseases driven by inflammation.

Cardiac expression of neutrophil gelatinase-associated lipocalin in a model of cancer cachexia-induced cardiomyopathy

AIMS

Cachexia is a severe consequence of cancer. Although cancer-induced heart atrophy leads to cardiac dysfunction and heart failure (HF), biomarkers for their diagnosis have not been identified. Neutrophil gelatinase-associated lipocalin (NGAL) is an aldosterone-responsive gene increased in HF. We studied NGAL and its association with aldosterone levels in a model of cancer cachexia-induced cardiomyopathy.

METHODS AND RESULTS

Rats were injected with Yoshida 108 AH-130 hepatoma cells to induce tumour. Cachectic rats were treated daily, for 16 days, with placebo or with 5 or 50 mg/kg/day of spironolactone. Cardiac function was analysed by echocardiography at baseline and at Day 11. Weight loss and atrophy of lean body and fat mass of cachectic rats were significantly attenuated by spironolactone. Cardiac dysfunction of tumour-bearing rats was improved by spironolactone. Plasma aldosterone was up-regulated from 337 ± 7 pg/mL in sham animals to 591 ± 31 pg/mL in the cachectic rats (P < 0.001 vs. sham). Treatment with 50 or 5 mg/kg/day of spironolactone reduced plasma aldosterone to 396 ± 22 and 391 ± 25 pg/mL (P < 0.01 vs. placebo). Plasma levels of NGAL were also increased in cachectic rats (1.462 ± 0.3603 μg/mL) than in controls (0.0936 ± 6 μg/mL, P < 0.001). Spironolactone treatment (50 mg/kg/day) significantly reduced cardiac mRNA and protein NGAL levels (P < 0.05 and P < 0.001 vs. placebo, respectively). NGAL mRNA and protein levels were overexpressed in cachectic animal hearts treated with placebo, compared with control (P < 0.05 and P < 0.01 vs. sham). Spironolactone treatment at 50 mg/kg/day reduced significantly cardiac NGAL (P < 0.05 and P < 0.001 vs. placebo).

CONCLUSIONS

Cancer cachexia induced increased levels of aldosterone and NGAL, contributing to worsening cardiac damage in cancer cachexia-induced cardiomyopathy. Spironolactone treatment may greatly attenuate cardiac dysfunction and lean mass atrophy associated with cancer cachexia.

The emerging role of aldosterone/mineralocorticoid receptors in the pathogenesis of erectile dysfunction

PURPOSE

Aldosterone is an old hormone that has been discovered for more than fifty years. The clinical application of its receptors' inhibitors, especially spirolactone, has benifited patients for decades worldwide. In this review, we briefly summarized the molecular mechanism of aldosterone/mineralocorticoid receptors (Ald-MRs) signaling in cardiovascular diseases and its emerging role in erectile dysfunction.

METHODS

We searched PubMed, Web of Science, and Scopus for manuscripts published prior to December 2017 using key words " aldosterone " AND " erectile dysfunction " OR " cardiovascular disease " OR " mineralocorticoid receptors ". Related literature and clinical perspectives were collated, summarized and discussed in this review.

RESULTS

The increase of reactive oxygen species production, inhibition of endothelial nitric oxide synthase system, and induction of inflammation are ubiquitous in vascular endothelial cells or vascular smooth muscle cells after the activation of Ald-MRs pathway. In addition, in cardiovascular diseases with over-active Ald-MRs signaling, MRs blockade could reverse the injury and improve the prognosis. Notably, multiple studies have correlated aldosterone and MRs to the pathogenesis of erectile function, while the mechanism is largely unperfectly identified.

CONCLUSION

In conclusion, we summarize the current evidence to highlight the potential role of aldosterone in erectile dysfunction and provide critical insights into the treatment of the disease.

Effects of mineralocorticoid receptor antagonists on responses to hemorrhagic shock in rats

AIM

To evaluate the effects of mineralocorticoid receptor (MR) antagonists on mortality and inflammatory responses after hemorrhagic shock (HS) in rats.

METHODS

One hundred and two male Sprague–Dawley rats were randomly assigned to one of the following three groups: Control, spironolactone (SPL), and eplerenone (EP) groups. HS was induced by the removal of blood. One half of rats were evaluated to determine mortality, hemodynamics, plasma tumor necrosis factor-alpha (TNF-α) concentrations, and arterial blood gas at 8 h after HS recovery. In the remainder of rats, the expression levels of genes encoding cytokines were evaluated in liver tissue samples at 1 h after HS recovery.

RESULTS

The survival rates 8 h after HS recovery were 71%, 94%, and 82% in the control, SPL, and EP groups, respectively. There were no significant differences in survival rates among the three groups (P = 0.219). Furthermore, there were no significant differences in gene expression levels in the liver or plasma TNF-α concentrations among the three groups (P = 0.888).

CONCLUSION

Pretreatment with MR antagonists did not improve mortality or cytokine responses in the liver after HS recovery in rats.

Spironolactone inhibits production of proinflammatory mediators in response to lipopolysaccharide via inactivation of nuclear factor-κB

The effect of spironolactone (SPIR) on lipopolysaccharide (LPS)-induced production of proinflammatory mediators was examined using RAW 264.7 macrophage-like cells and mouse peritoneal macrophages. SPIR significantly inhibited LPS-induced production of nitric oxide (NO), tumor necrosis factor-α and prostaglandin E2. The inhibition was not mediated by cell death. SPIR reduced the expression of an inducible NO synthase mRNA in response to LPS. SPIR significantly inhibited phosphorylation of p65 nuclear factor (NF)-κB in response to LPS. Furthermore, SPIR inhibited phosphorylation of IκB kinase (IKK) as an upstream molecule of NF-κB in response to LPS. LPS did not induce the production of aldosterone in RAW 264.7 cells. Taken together, SPIR is suggested to inhibit LPS-induced proinflammatory mediators via inactivation of IKK/NF-κB in LPS signaling.

A pilot study of the effect of spironolactone therapy on exercise capacity and endothelial dysfunction in pulmonary arterial hypertension: study protocol for a randomized controlled trial

BACKGROUND

Pulmonary arterial hypertension is a rare disorder associated with poor survival. Endothelial dysfunction plays a central role in the pathogenesis and progression of pulmonary arterial hypertension. Inflammation appears to drive this dysfunctional endothelial phenotype, propagating cycles of injury and repair in genetically susceptible patients with idiopathic and disease-associated pulmonary arterial hypertension. Therapy targeting pulmonary vascular inflammation to interrupt cycles of injury and repair and thereby delay or prevent right ventricular failure and death has not been tested. Spironolactone, a mineralocorticoid and androgen receptor antagonist, has been shown to improve endothelial function and reduce inflammation. Current management of patients with pulmonary arterial hypertension and symptoms of right heart failure includes use of mineralocorticoid receptor antagonists for their diuretic and natriuretic effects. We hypothesize that initiating spironolactone therapy at an earlier stage of disease in patients with pulmonary arterial hypertension could provide additional benefits through anti-inflammatory effects and improvements in pulmonary vascular function.

METHODS/DESIGN

Seventy patients with pulmonary arterial hypertension without clinical evidence of right ventricular failure will be enrolled in a randomized, double-blinded, placebo-controlled trial to investigate the effect of early treatment with spironolactone on exercise capacity, clinical worsening and vascular inflammation in vivo. Our primary endpoint is change in placebo-corrected 6-minute walk distance at 24 weeks and the incidence of clinical worsening in the spironolactone group compared to placebo. At a two-sided alpha level of 0.05, we will have at least 84% power to detect an effect size (group mean difference divided by standard deviation) of 0.9 for the difference in the change of 6-minute walk distance from baseline between the two groups. Secondary endpoints include the effect of spironolactone on the change in placebo-corrected maximal oxygen consumption; plasma markers of vascular inflammation and peripheral blood mononuclear cell gene expression profiles; sympathetic nervous system activation, renin-angiotensin-aldosterone system activation and sex hormone metabolism; and right ventricular structure and function using echocardiography and novel high-resolution magnetic resonance imaging-based techniques. Safety and tolerability of spironolactone will be assessed with periodic monitoring for hyperkalemia and renal insufficiency as well as the incidence of drug discontinuation for untoward effects.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01712620.

Blood pressure has only minor influence on aldosterone-induced oxidative stress and DNA damage in vivo

Epidemiological studies found an increased kidney cancer risk in hypertensive patients. These patients frequently present an increase in the mineralocorticoid aldosterone (Ald) due to a stimulated renin angiotensin aldosterone system (RAAS). Recently, we showed pro-oxidative and genotoxic effects of Ald in vitro. Here, we investigated the influence of blood pressure on aldosterone-induced oxidative damage. To distinguish whether effects in Sprague-Dawley rats treated with Ald were caused by Ald or by increased blood pressure, the mineralocorticoid receptor (MR) antagonist spironolactone was administered in a subtherapeutical dose, not lowering the blood pressure, and hydralazine, a RAAS-independent vasodilator, was given to normalize the pressure. With the antioxidant tempol, oxidative stress-dependent effects were demonstrated. Ald treatment caused kidney damage and oxidative and nitrative stress. Structural DNA damage and the mutagenic oxidative base modification 7,8-dihydro-8-oxoguanine were increased, as well as DNA repair activity and nuclear NF-κB translocation. Spironolactone and tempol decreased all markers significantly, whereas hydralazine had just slight effects. These data comprise the first report of essentially blood pressure-independent tissue- and DNA-damaging effects of Ald. A fully activated MR and the production of reactive oxygen and nitrogen species were crucial for these effects.

Aldosterone, oxidative stress, and NF-κB activation in hypertension-related cardiovascular and renal diseases

The mineralocorticoid aldosterone regulates electrolyte and fluid balance and is involved in blood pressure homoeostasis. Classically, it binds to its intracellular mineralocorticoid receptor to induce expression of proteins influencing the reabsorption of sodium and water in the distal nephron. Aldosterone gained special attention when large clinical studies showed that blocking its receptor in patients with cardiovascular diseases reduced their mortality. These patients present increased plasma aldosterone levels. The exact mechanisms of the potential toxic effects of aldosterone leading to cardiovascular damage are not known yet. The observation of reduced nitric oxide bioavailability in hyperaldosteronism implied the generation of oxidative stress by aldosterone. Subsequent studies confirmed the increase of oxidative stress markers in patients with chronic heart failure and in animal models of hyperaldosteronism. The effects of reactive oxygen species have been related to the activation of transcription factors, such as NF-κB. This review summarizes the present-day knowledge of aldosterone-induced oxidative stress and NF-κB activation in humans and different experimental models.

Intrathecal injection of spironolactone attenuates radicular pain by inhibition of spinal microglia activation in a rat model

Background

Microglia might play an important role in nociceptive processing and hyperalgesia by neuroinflammatory process. Mineralocorticoid receptor (MR) expressed on microglia might play a central role in the modulation of microglia activity. However the roles of microglia and MR in radicular pain were not well understood. This study sought to investigate whether selective MR antagonist spironolactone develop antinociceptive effects on radicular pain by inhibition neuroinflammation induced by spinal microglia activation.

Results

Radicular pain was produced by chronic compression of the dorsal root ganglia with SURGIFLO™. The expression of microglia, interleukin beta (IL-1β), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), NR1 subunit of the NMDA receptor (t-NR1), and NR1 subunit phosphorylated at Ser896 (p-NR1) were also markedly up-regulated. Intrathecal injection of spironolactone significantly attenuated pain behaviors as well as the expression of microglia, IL-1β, TNF-α, t-NR1, and p-NR1, whereas the production of IL-6 wasn’t affected.

Conclusion

These results suggest that intrathecal delivery spironolactone has therapeutic effects on radicular pain in rats. Decreasing the activation of glial cells, the production of proinflammatory cytokines and down-regulating the expression and phosphorylation of NMDA receptors in the spinal dorsal horn and dorsal root ganglia are the main mechanisms contributing to its beneficial effects.

Effects of aldosterone and related steroids on LPS-induced increased expression of inducible NOS in rat aortic smooth muscle cells

BACKGROUND AND PURPOSE

Expression of inducible NOS (iNOS) is important in certain inflammatory diseases. We determined if the hormone aldosterone, a mineralocorticoid receptor (MR) agonist, affects LPS activation of iNOS expression in rat aortic smooth muscle cells (RASMC).

EXPERIMENTAL APPROACH

Cultured RASMC were treated with LPS, with or without agonists/antagonists of steroid receptors. iNOS expression was determined by nitrite assays on culture medium removed from treated cells and by immunoblotting of cell protein extracts.

KEY RESULTS

LPS (1 µg·mL(-1) ) increased nitrite and iNOS protein above that in control (untreated) cells. These effects of LPS were reduced by aldosterone (0.1-10 µM). The MR antagonists, eplerenone (10 µM) and spironolactone (10 or 50 µM), did not inhibit these actions of 1 µM aldosterone, but the latter were prevented by 10 µM mifepristone, a glucocorticoid (GR) and progestogen receptor (PR) antagonist. Mifepristone also prevented the reduction of LPS-induced nitrite increase produced by 1 µM dexamethasone (GR agonist) and 10 µM progesterone (PR agonist). Spironolactone (10-50 µM) by itself decreased LPS-induced increases in nitrite and iNOS protein. Mifepristone (10 µM) partially reversed these effects of 10 µM spironolactone, but not those of 50 µM; the effects of 50 µM spironolactone were also unchanged when mifepristone was increased to 50 µM.

CONCLUSIONS AND IMPLICATIONS

This pharmacological profile suggests that aldosterone, and possibly 10 µM spironolactone, use mechanisms that are dependent on PR and/or GR, but not MR, to inhibit iNOS induction in RASMC. With 50 µM spironolactone, other inhibitory mechanisms requiring further investigation may become predominant.

Aldosterone promotes autoimmune damage by enhancing Th17-mediated immunity

Excessive production of aldosterone leads to the development of hypertension and cardiovascular disease by generating an inflammatory state that can be promoted by T cell immunity. Because nature and intensity of T cell responses is controlled by dendritic cells (DCs), it is important to evaluate whether the function of these cells can be modulated by aldosterone. In this study we show that aldosterone augmented the activation of CD8(+) T cells in a DC-dependent fashion. Consistently, the mineralocorticoid receptor was expressed by DCs, which showed activation of MAPK pathway and secreted IL-6 and TGF-beta in response to aldosterone. In addition, DCs stimulated with aldosterone impose a Th17 phenotype to CD4(+) T cells, which have recently been associated with the promotion of inflammatory and autoimmune diseases. Accordingly, we observed that aldosterone enhances the progression of experimental autoimmune encephalomyelitis, an autoimmune disease promoted by Th17 cells. In addition, blockade of the mineralocorticoid receptor prevented all aldosterone effects on DCs and attenuated experimental autoimmune encephalomyelitis development in aldosterone-treated mice. Our data suggest that modulation of DC function by aldosterone enhances CD8(+) T cell activation and promotes Th17-polarized immune responses, which might contribute to the inflammatory damage leading to hypertension and cardiovascular disease.

Ameliorative potential of spironolactone in diabetes induced hyperalgesia in mice

The present study was designed to investigate the ameliorative potential of spironolactone against diabetic hyperalgesia in mice. Tail flick latency, an index of hyperalgesia, was assessed by analgesiometer. Serum nitrite levels, an index of nitric oxide, were analyzed by Griess reaction. Mice were rendered diabetic with streptozotocin (200 mg kg(-1) i.p) and kept for 30 days for development of diabetic pain. Thereafter, spleen homogenate supernatant (SHS) was prepared from the mouse spleen and administered in normal mice for 14 days. In both diabetic and SHS-treated mice a significant degree of hyperalgesia was developed, suggesting the key role of spleen-derived factor in induction of diabetic pain. Moreover, the levels of nitric oxide were also elevated in 30th day diabetic mice and SHS-treated mice. Administration of spironolactone (7 and 15 mg kg(-1) p.o.) significantly attenuated diabetes-induced decrease of nociceptive threshold and increase of serum nitrite oxide levels. Furthermore, SHS of spironolactone-treated diabetic mice failed to induce hyperalgesia and to increase serum nitrite levels. These results suggest that spironolactone has ameliorative potential in attenuating the hyperalgesia associated with diabetes, which may be possibly mediated through inhibition of release of certain critical factors from spleen.

Mineralocorticoid receptor antagonism attenuates vascular apoptosis and injury via rescuing protein kinase B activation

Emerging evidence indicates that mineralocorticoid receptor (MR) blockade reduces the risk of cardiovascular events beyond those predicted by its blood pressure-lowering actions; however, the underlying mechanisms remain unclear. To investigate whether protection elicited by MR blockade is through attenuation of vascular apoptosis and injury, independently of blood pressure lowering, we administered a low dose of the MR antagonist spironolactone or vehicle for 21 days to hypertensive transgenic Ren2 rats with elevated plasma aldosterone levels. Although Ren2 rats developed higher systolic blood pressures compared with Sprague-Dawley littermates, low-dose spironolactone treatment did not reduce systolic blood pressure compared with untreated Ren2 rats. Ren2 rats exhibited vascular injury as evidenced by increased apoptosis, hemidesmosome-like structure loss, mitochondrial abnormalities, and lipid accumulation compared with Sprague-Dawley rats, and these abnormalities were attenuated by MR antagonism. Protein kinase B activation is critical to vascular homeostasis via regulation of cell survival and expression of apoptotic genes. Protein kinase B serine(473) phosphorylation was impaired in Ren2 aortas and restored with MR antagonism. In vivo MR antagonist treatment promoted antiapoptotic effects by increasing phosphorylation of BAD serine(136) and expression of Bcl-2 and Bcl-xL, decreasing cytochrome c release and BAD expression, and suppressing caspase-3 activation. Furthermore, MR antagonism substantially reduced the elevated NADPH oxidase activity and lipid peroxidation, expression of angiotensin II, angiotensin type 1 receptor, and MR in Ren2 vasculature. These results demonstrate that MR antagonism protects the vasculature from aldosterone-induced vascular apoptosis and structural injury via rescuing protein kinase B activation, independent of blood pressure effects.

Hemodynamic effects of propranolol with spironolactone in patients with variceal bleeds: A randomized controlled trial

AIM: To study the hemodynamic effects of spironolactone with propranolol vs propranolol alone in the secondary prophylaxis of variceal bleeding.

METHODS: Thirty-five cirrhotics with variceal bleeding randomly received propranolol (n = 17: Group A) or spironolactone plus propranolol (n = 18: Group B). Hemodynamic assessment was performed at baseline and on the eighth day.

RESULTS: Spironolactone with propranolol caused a greater reduction in the hepatic venous pressure gradient than propranolol alone (26.94% vs 10.2%; P < 0.01). Fourteen out of eighteen patients on the combination treatment had a reduction in hepatic venous pressure gradient to ≤ 12 mmHg or a 20% reduction from baseline in contrast to only six out of seventeen (6/17) on propranolol alone (P < 0.05).

CONCLUSION: Spironolactone with propranolol results in a better response with a greater reduction in hepatic venous pressure gradient in the secondary prophylaxis of variceal bleeding. A greater number of patients may be protected by this combination therapy than by propranolol alone. Hence, this combination may be recommended for secondary prophylaxis in patients with variceal bleeding.

Altered collagen homeostasis in human aortic smooth muscle cells (HAoSMCs) induced by aldosterone

The importance of aldosterone for cardiovascular diseases is well established. Most of the adverse effects seem to originate from its ability to produce vascular injury, including fibrosis. It is currently under debate whether aldosterone per se is able to induce fibrosis or whether it acts as a cofactor under pathological conditions. We tested whether aldosterone per se and in the presence of reactive oxygen stress (H(2)O(2)) enhances collagen abundance in human aortic smooth muscle cell (HAoSMC) media in primary culture and, if so, by which means. Collagen abundance, as well as epidermal growth factor receptor (EGFR) expression and ERK1/2 phosphorylation, was investigated by ELISA and Western blot. Collagenase activity and H(2)O(2) formation were determined by fluorometry and luminometry. Aldosterone alone did not affect collagen abundance but potentiated the stimulatory effect of low concentrations of H(2)O(2) (1-10 micromol/l). This effect disappeared when shedding of membrane-bound EGFR ligands was prevented by GM6001. EGFR expression and cellular EGF responsiveness were enhanced by aldosterone. Inhibition of the EGFR kinase (tyrphostin AG1478) prevented the increase of collagen. The increase in collagen abundance was prevented by blockade of the mineralocorticoid receptor (MR) and could be reproduced by MR transfection into Chinese hamster ovary cells. We conclude that aldosterone sensitizes HAoSMC for H(2)O(2)-induced increase of collagen abundance at least in part by enhanced EGFR expression.