Purpose:Evaluation of hernia therapies according to the current rules of Evidence Based Medicine is widely reduced to results of RCTs or meta-analyses. RCTs have been accepted as a most important tool to confirm a superior effect of an intervention. Unfortunately, in hernia surgery, comparisons of RCTs and correspondingly their use in meta-analyses, are not, surprisingly often, able to confirm any significant impact of a specific procedure due to intrinsic restrictions in a multi-causal setting with its web of influences. Methods:Based on our own experiences of clinical studies in surgery, the present article outlines several situations, with their respective reasons, which argue the severe limitations of RCTs and meta-analysis to define an optimum treatment. Results:Meta-analyses accumulate the variations of each trial, which then may cover any clear causal relationship. RCTs usually are dealing with subgroups of standard patients thus excluding the majority of our patients. Low statistical power of current cohort sizes restricts the analysis of subgroups or of effects with low incidences. Simple comparisons of means frequently are hampered by nonlinear relationships to outcome. The relevance of a specific variable is difficult to separate from other influences. The limited surveillance period of studies ignores a delayed change in outcome. Randomization cannot guarantee a standardized patient’s condition. All the arguments have to be considered as a crucial and fundamental consequence of the bias-variance dilemma or principle of uncertainty in medicine, and underline the many limitations of RCTs to evaluate any specific impact of hernia therapies on e.g. infection, pain or recurrence. Conclusions: Many surgical issues cannot be and should not be investigated by RCTs, in particular, if a marked patients’ heterogeneity has to be considered or the low incidences of the outcome readout cannot be addressed with sufficient statistical power without getting lost in the variation mire. Registries with their non-restricted data-acquisition should be regarded as reliable alternatives for postoperative outcome quality surveillance studies.

Aldosterone (Aldo) is involved in vascular remodeling and inflammation; however, the mechanisms are imperfectly defined. We hypothesized that Aldo alters endothelial integrity and modifies paracellular permeability. Human umbilical vein endothelial cells were exposed to Aldo (10 –9 mol/L) and alterations in paracellular permeability, assembly of tight and adherens junctions and activation of intracellular signaling pathways were determined. Aldo increased endothelial permeability for molecules ≤70 kDa within 60 minutes. A transient loss of cortical actin with formation of actin stress fibers and disruption of continuous adherens and tight junction strands accompanied these changes. Mineralocorticoid receptor blockade, inhibition of RhoA, or disruption of extracellular-regulated protein kinase1/2 signaling pathways attenuated the Aldo-related effects. Moreover, Aldo-induced cytoskeletal rearrangement led to rapid dephosphorylation of protein kinase B and subsequent deactivation of endothelial nitric oxide synthase. Ex vivo tracer flux experiments with Evans blue–conjugated albumin demonstrated a concordant response to Aldo in freshly isolated umbilical arteries. Furthermore, low-dose cortisol (3×10 –10 to 3×10 –9 mol/L) mimics the effect of Aldo on endothelial integrity, and Aldo, by upregulating11β-hydroxysteroid dehydrogenase type 2, might even aggravate this deleterious effect of low-dose cortisol. We suggest that these mechanisms may contribute to the vasculopathy induced by inappropriate mineralocorticoid receptor activation.

BACKGROUND Macrophages are major effectors of the local inflammatory response syndrome (LIRS) and influence the extent of ischaemia/reperfusion injury, thereby impacting organ function. Several subgroups of macrophages exist, representing distinct modes of action. The specific role of the subset expressing Fc gamma receptor (FcγR) 1 in the activated state of macrophages is poorly defined. METHODS We induced a LIRS via 30 min of ischaemia in uninephrectomized rats, transgenic for the human FcγR1. Six hours after reperfusion, the treatment group was injected with a recombinant immunotoxin (IT) H22(scFv)-ETA' targeted against human FcγR1, which induced apoptosis of target cells. The placebo group received normal saline (NS). Contralateral kidneys served as healthy controls (Ctr). After 24 h of reperfusion, the animals were analysed. RESULTS Targeted treatment with IT resulted in preserved renal function [NS versus IT treatment and baseline (creatinine: 69.2 ± 2.6, 54.7 ± 3.4 and 27.3 ± 1.0 μmol/L; P < 0.001)]. The number of all infiltrating monocytes were significantly reduced (CD68-positive cells per view field: NS 3.8 ± 0.4, IT 2.5 ± 0.2 and Ctr 1.2 ± 0.4; P < 0.05), renal histology improved and there was a reduced expression of renal fibronectin (NS 4.0 ± 0.4, IT 2.3 ± 0.2 and Ctr 1.1 ± 0.1; P < 0.001). Following IT administration, we also observed less expression of renal monocyte chemoattractant protein-1-positive cells per view field (NS 19.0 ± 1, IT 10.1 ± 0.8 and Ctr 2.0 ± 0.3; P < 0.001) as well as reduced systemic and local oxidative stress [serum malondialdehyde (MDA): NS 340 ± 30, IT 224 ± 36 versus baseline 140 ± 5 nmol/mL; P < 0.01]; renal MDA arbitrary units of fluorescence intensity: NS 3.7 ± 0.2, IT 1.8 ± 0.3 and Ctr 0.4 ± 0.2; P < 0.001. CONCLUSIONS Reduction of FcγR1-up-regulated monocytic cells leads to preserved renal function and morphology in a rat model of ischaemia-triggered LIRS. Our results show that targeting activated macrophages is a valuable approach for ameliorating ischaemia-induced tissue injury.

Aldosterone (Ald) is involved in vascular remodeling and inflammation; however, the mechanisms are imperfectly defined. We hypothesized that Ald alters endothelial integrity and modifies paracellular permeability. Human umbilical vein endothelial cells (HUVEC) were exposed to Ald (10 -9 mol/L) and alterations in paracellular permeability, assembly of tight and adherens junctions, and activation of intracellular signaling pathways were determined. Ald increased endothelial paracellular permeability for molecules up to 70 kDa within 60 min. A transient loss of cortical actin with formation of actin stress fibers, and disruption of continuous adherens and tight junction strands, accompanied the changes. Mineralocorticoid receptor (MR) blockade, inhibition of RhoA or disruption of extracellular regulated protein kinase (ERK) 1/2 signaling pathways attenuated the Ald-related effects. Moreover, the observed changes of the actin cytoskeleton and intercellular junction architecture were accompanied by a rapid dephosphorylation of protein kinase B (AKT) as well as deactivation of endothelial NO synthase (eNOS). Ex vivo tracer flux experiments with Evans Blue (EB)-conjugated albumin demonstrated concordant response to Ald in freshly isolated umbilical arteries. In summary, Ald leads to increased permeability of endothelial monolayer or isolated arteries. These alterations are associated with a temporal opening of Intercellular junctions and diminished eNOS activity, and depend on activation of the RhoA/ERK pathway. We conclude that these mechanisms could contribute to Ald-induced vasculopathy.

Prosthetic reinforcements markedly reduce the risk of hernia recurrence. However, the implantation of meshes is related to an inflammatory foreign body reaction (FBR) with serious complications (i.e., persistent seroma, wound infection, mesh migration, entrapment, chronic pain). Adrenal hormones profoundly modify inflammatory response. Their effects on FBR however, remain ill defined. We therefore studied the FBR to polyvinylidenfluoride (PVDF) mesh material that was coated with four different substances: hydrocortisone (COR) or mifepristone (MIF), which respectively stimulate and block the glucocorticoid receptor, and aldosterone (ALD) or spironolactone (SPI), which respectively stimulate and block the mineralocorticoid receptor. The coated substances were released from the meshes within 24 h. Seven, 21, and 90 days after implantation, the specimen was evaluated for collagen formation, granuloma size, inflammatory activity, and angiogenesis. COR and SPI coating protected from inflammatory response, while ALD and MIF coating showed little difference to the control group. The COR and SPI groups showed smaller granuloma sizes at all time points, as well as a reduced number of inflammatory cells (p < 0.001) at day 90, and decreased collagen formation starting after 21 days (p < 0.05). There was a negative correlation for angiogenesis with inflammation around foreign body structures. In summary, these results suggest that early and temporary stimulation of the glucocorticoid receptor or blockade of the mineralocorticoid receptor have beneficial effects on FBR in the long term.

Background: Mesh reinforcement in hiatal hernia repair becomes more frequent but is charged by complications such as erosion or stenosis of the oesophagus. These complications are accompanied by an intense inflammatory infiltrate around the polymer fibres. To characterize this effect, the response to polypropylene fibres in the absence of tension was examined. Methods: In rats, polypropylene sutures (USP size 1, 3-0 and 7-0) were placed in the subcutis of the abdominal wall without knot or tension. On postoperative days 3, 7 and 21, specimens were excised. The expressions of c-myc, β-catenin, Notch3, COX-2, CD68 and Ki-67 were measured by immunohistochemistry. Results: In the absence of tension, sutures were surrounded by a foreign body granuloma with an inflammatory infiltrate not encircling the fibre but forming almost symmetric comet-tail-like infiltrates on opposite sides. The expression of c-myc, β-catenin, Notch3, COX-2, CD68 and Ki-67 was significantly reduced over time in the comet tail, but not in the granuloma. Conclusions: Even in tension-free conditions, surgical sutures cause a foreign body response with infiltrates of inflammatory cells. This reaction is shaped like a comet tail, and its extension depends on the diameter of the used fibre. Therefore, for reduction of perifilamental infiltrates, not only absence of tension is required, but also a small-sized fibre textile.

In humans, dehydroepiandrosterone (DHEA), with its sulfate, is the most abundant adrenal steroid, whereas the rat adrenals are not capable of synthesizing this steroid. Circulating concentrations of DHEA sulfate lie in the millimolar range and those of DHEA in the subnanomolar range. DHEA exerts protective potential during vascular remodeling, although the underlying mechanisms of this protection are imperfectly defined. We hypothesized that physiological doses of DHEA alter signaling pathways that are of central importance for vascular integrity. We exposed human endothelial cells, vascular smooth muscle cells, and fibroblasts to DHEA (10 6 to 10 10 mol/L) and observed a doseand time-dependent increase of extracellular signal-regulated kinases 1 and 2 activation. Similar results were observed in rat vascular smooth muscle cells. In addition, in rat vascular smooth muscle cells, we found altered phosphorylation and cellular translocation of the transcription factor FoxO1. Pharmacological blockade of the mineralocorticoid receptor (MR) with eplerenone or small interfering RNA-mediated MR-silencing prevented DHEA-induced extracellular signal-regulated kinase 1/2 phosphorylation and its effects on FoxO1. Of note, in a cell-based MR transactivation assay, we did not find any agonist effect of DHEA on MR activity. We conclude that DHEA induces early signaling events in vascular cells that might underlie the DHEA-mediated protection against vasculopathies. These effects are dependent on the MR, although the finding that DHEA fails to act as a direct MR agonist suggests that additional signaling proteins are involved. In this regard, DHEA may either interact with coeffectors to modify MR activity or serves as a ligand for a yet unknown receptor that might transactivate the MR. (Hypertension. 2011;58:471-478.) ● Online Data Supplement

Aldosteron ist ein Nebennierenrindenhormon mit pleiotroper Wirkung. Es stimuliert den Mineralokortikoidrezeptor (MR), der an zahlreichen physiologischen und pathophysiologischen Prozessen beteiligt ist; eine verstärkte Aktivität zusammen mit einer inadäquat hohen Salzzufuhr führt zu Bluthochdruck und entzündlich fibrotischen Veränderungen im Gewebe. Darüber hinaus werden zahlreiche weitere Regelkreise beeinflusst, z. B. solche, die in die Regulation der Geweberegeneration oder der renalen Eiweißausscheidung eingebunden sind. Häufige Ursachen für die verstärkte Aktivierung des MR sind einseitige Nebennierenadenome und eine bilaterale Hyperplasie mit unkontrollierter Aldosteronsynthese. Therapieoptionen umfassen die operative Entfernung eines Tumors und die medikamentöse Blockade des MR. Zu den klinisch relevanten Perspektiven zählen die Entwicklung neuer, selektiver Antagonisten der MR-Aktivität mit verminderten Nebenwirkungen bzw. die erweiterte Indikation von MR-Blockern.

BACKGROUND:Personalised cancer therapy, such as that used for bronchial carcinoma (BC), requires treatment to be adjusted to the patient's status. Individual risk for progression is estimated from clinical and molecular-biological data using translational score systems. Additional molecular information can improve outcome prediction depending on the marker used and the applied algorithm. Two models, one based on regressions and the other on correlations, were used to investigate the effect of combining various items of prognostic information to produce a comprehensive score. This was carried out using correlation coefficients, with options concerning a more plausible selection of variables for modelling, and this is considered better than classical regression analysis.METHODS:Clinical data concerning 63 BC patients were used to investigate the expression pattern of five tumour-associated proteins. Significant impact on survival was determined using log-rank tests. Significant variables were integrated into a Cox regression model and a new variable called integrative score of individual risk (ISIR), based on Spearman's correlations, was obtained.RESULTS:High tumour stage (TNM) was predictive for poor survival, while CD68 and Gas6 protein expression correlated with a favourable outcome. Cox regression model analysis predicted outcome more accurately than using each variable in isolation, and correctly classified 84% of patients as having a clear risk status. Calculation of the integrated score for an individual risk (ISIR), considering tumour size (T), lymph node status (N), metastasis (M), Gas6 and CD68 identified 82% of patients as having a clear risk status.CONCLUSION:Combining protein expression analysis of CD68 and GAS6 with T, N and M, using Cox regression or ISIR, improves prediction. Considering the increasing number of molecular markers, subsequent studies will be required to validate translational algorithms for the prognostic potential to select variables with a high prognostic power; the use of correlations offers improved prediction.

BACKGROUND:Glucocorticoids (GC) represent the core treatment modality for many inflammatory diseases. Its mode of action is difficult to grasp, not least because it includes direct modulation of many components of the extracellular matrix as well as complex anti-inflammatory effects. Protein expression profile of skin proteins is being changed with topical application of GC, however, the knowledge about singular markers in this regard is only patchy and collaboration is ill defined.MATERIAL/METHODS:Scar formation was observed under different doses of GC, which were locally applied on the back skin of mice (1 to 3 weeks). After euthanasia we analyzed protein expression of collagen I and III (picrosirius) in scar tissue together with 16 additional protein markers, which are involved in wound healing, with immunhistochemistry. For assessing GC's effect on co-expression we compared our results with a model of random figures to estimate how many significant correlations should be expected by chance.RESULTS:GC altered collagen and protein expression with distinct results in different areas of investigation. Most often we observed a reduced expression after application of low dose GC. In the scar infiltrate a multivariate analysis confirmed the significant impact of both GC concentrations. Calculation of Spearman's correlation coefficient similarly resulted in a significant impact of GC, and furthermore, offered the possibility to grasp the entire interactive profile in between all variables studied. The biological markers, which were connected by significant correlations could be arranged in a highly cross-linked network that involved most of the markers measured. A marker highly cross-linked with more than 3 significant correlations was indicated by a higher variation of all its correlations to the other variables, resulting in a standard deviation of > 0.2.CONCLUSION:In addition to immunohistochemical analysis of single protein markers multivariate analysis of co-expressions by use of correlation coefficients reveals the complexity of biological relationships and identifies complex biological effects of GC on skin scarring. Depiction of collaborative clusters will help to understand functional pathways. The functional importance of highly cross-linked proteins will have to be proven in subsequent studies.

Surgeons have been working for decades to improve their technique and to develop better procedures. In doing so, they try to prove the effect of every modification by clinical randomized controlled trials (RCTs). The process should result in a best technique that can then be considered the gold standard. This recommendation is outlined in so-called guidelines offering evidence-based knowledge to every physician. However, although RCTs have been performed with increasing efforts, these often fail to confirm any significant differences between the groups involved. Furthermore, after replication by other investigators, the overall results differ considerably in outcome, making interpretation of the results rather complicated. Even the collection of several trials in meta-analyses often does not ease interpretation. It appears that for some questions, the RCT instrument needs some support to verify the superiority of one procedure over another.

The endothelium represents the central vascular barrier and circulating solutes or ions have to pass this barrier before they can affect the underlying tissue. Thus, altered paracellular permeability is a major attribute of diseases associated with endothelial dysfunction. The mineralocorticoid aldosterone is described to induce ischemic tissue damage and tissue remodeling. Its effect is mainly traced back to alterations in gene expression or intracellular signaling cascades. We here investigated the role of aldosterone on tight junctions in human endothelial cells. Aldosterone (10–9 mol/L) induced a temporal disassembly of cortical F-actin rings and formation of stress fibers with a maximum at 60 minutes. Concordantly, we observed changes in cellular distribution of VE-cadherin, ZO-1, occludin and claudin-5 suggesting rearrangements of adherens and tight junctions. Aldosterone-induced alterations of actin dynamics and junction integrity were associated with temporally increased paracellular permeability and could be prevented by inhibition of the mineralocorticoid receptor as well as by blocking activation of protein kinase B or ERK1/2. In summary, we have shown that aldosterone leads to temporal breakdown of endothelial tight junctions and enhanced paracellular passage. These findings will pave the way for further in vivo studies on aldosterone-induced alterations of endothelial barrier properties.

Adrenal hormones influence inflammatory and fibrotic activity and thereby are involved in wound-healing process. Any excess as well as any shortage of glucocorticoids leads to a delayed wound healing. Mineralocorticoids like aldosterone have a pro-fibrotic and pro-inflammatory impact; thus, reduction of circulating aldosterone should result in an attenuated inflammatory response to implanted foreign bodies.

BACKGROUND & AIMS:The aim of our study was to search for highly up-regulated genes in primary malignant liver tumours and to analyse their expression at the mRNA- and protein level. METHODS:Using a random-based gene fishing approach (representational difference analysis coupled to array hybridisation) we identified 7 genes high abundantly expressed in hepatocellular carcinoma (HCC) as compared to non-neoplastic liver tissue, among them a gene fragment of the aldo-ketoreductase (AKR) superfamily. Full length cloning and sequencing of the gene fragment identified it as B10 gene of the AKR-family 1 (AKR1B10). For expression analysis on transcriptional level quantitative real-time RT-PCR was performed in 22 HCC and 22 non-neoplastic liver cirrhotic tissues. RESULTS:Our data demonstrate significantly higher expression levels of AKR1B10-mRNA in HCC compared to non-tumourous cirrhotic liver tissue (p<0.0001). To evaluate its protein expression in primary malignant liver tumours, we investigated tissue arrays of 210 HCC and 51 cholangiocarcinomas (CC) by immunohistochemistry, using a monoclonal antibody against AKR1B10. Protein staining of AKR1B10 was significantly increased in well and moderately differentiated tumours compared to corresponding non-neoplastic liver tissue (p=0.023). However, AKR1B10-staining decreased in advanced, low differentiated tumours with a significant inverse correlation between AKR1B10-staining and tumour proliferation, indicated by Ki67 (MIB-1) staining (r=-0.89, p=0.02). CONCLUSION:The over-expression of AKR1B10 in early stages of well and moderately differentiated tumours and its down-regulation in advanced tumour-stages with low grade of differentiation demonstrated that AKR1B10 may be a helpful marker for differentiation and proliferation of HCC and CC.

Improving technology helps us to identify more and more defects at the level of genes or proteins (event) as potential sources of a disease (effect), hopefully allowing more targeted cures with a "magic bullet". However, the complex interference of genes by the environment hinders the detection of strict causal relationships between defect and disease. We consider causality as temporal relationship between event and effect, thus causation is reflected by the configuration of "survival" curves. This is indicated by several survival curves of diseases with known causal relation. Furthermore, we discuss three theoretical models: a causal chain model, a causal field concept and a causal chain model with variable order, and present three assumptions about the specific consequences for configuration of outcome curves. Clinical examples of diseases that are caused by single hits reveal an S-shaped curve of cumulative incidence. In contrast, for diseases with numerous interacting pathogenetic effectors the superposition of all contributions results in widely linear cumulative incidence curves. The rare S-shaped deformation in the survival curves in patients with recurrent cancer is in conflict with our current view of recurrent cancer as mainly being a consequence of residual tumour cell load. The assumption of a "web of causation" instead of a "causal chain" reflects a more real situation for many clinical problems and can explain the widely seen absence of decisive, causally relevant conditions. As consequences for our current treatment of cancer is not insignificant, a careful analysis of the configuration of outcome curves with recognition of an S-shape may either help to identify causal therapies or may encourage more comprehensive approaches that consider the complexity of the disease.

Growth arrest–specific protein 6 (Gas 6) is involved in inflammatory kidney diseases, vascular remodeling, cell adhesion, and thrombus formation. We explored a role for Gas 6 in aldosterone-induced target organ damage. We observed that Gas 6 was upregulated in rats with high aldosterone levels. Mineralocorticoid receptor blockade prevented target organ damage and decreased the elevated Gas 6 expression. Vascular smooth muscle cells given aldosterone increased their Gas 6 expression in vitro. To test the pathophysiological relevance, we investigated the effects of deoxycorticosterone acetate (DOCA) on Gas 6 gene-deleted ( −/− ) mice. After 6 weeks DOCA, Gas 6 −/− mice developed similar telemetric blood pressure elevations compared to wild-type mice but were protected from cardiac hypertrophy. Cardiac expression of interleukin 6 and collagen IV was blunted in Gas 6 −/− mice, indicating reduced inflammation and fibrosis. Gas 6 −/− mice also had an improved renal function with reduced albuminuria, compared to wild-type mice. Renal fibrosis and fibronectin deposition in the kidney were also reduced. Gas 6 deficiency reduces the detrimental effects of aldosterone on cardiac and renal remodeling independent of blood pressure reduction. Gas 6 appears to play a role in mineralocorticoid receptor-mediated target organ damage. Furthermore, because warfarin interferes with Gas 6 protein expression, the findings could be of clinical relevance for anticoagulant choices.

OBJECTIVE:We showed earlier that statin treatment ameliorates target-organ injury in a transgenic model of angiotensin (Ang) II-induced hypertension. We now test the hypothesis that rosuvastatin (1, 10, and 50 mg/kg/day) influences leukocyte adhesion and infiltration, prevents induction of inducible nitric oxide synthase (iNOS), and ameliorates target-organ damage in a dose-dependent fashion.METHODS:We treated rats harboring the human renin and human angiotensinogen genes (dTGR) from week 4 to 8 (n = 20 per group). Untreated dTGR developed severe hypertension, cardiac hypertrophy, and renal damage, with a 100-fold increased albuminuria and focal cortical necrosis. Mortality of untreated dTGR at age 8 weeks was 59%.RESULTS:Rosuvastatin treatment decreased mortality dose-dependently. Blood pressure was not affected. Albuminuria was reduced dose-dependently. Interstitial adhesion molecule (ICAM)-1 expression was markedly reduced by rosuvastatin, as were neutrophil and monocyte infiltration. Immunohistochemistry showed an increased endothelial and medial iNOS expression in small vessels, infiltrating cells, afferent arterioles, and glomeruli of dTGR. Immunoreactivity was stronger in cortex than medulla. Rosuvastatin markedly reduced the iNOS expression in both cortex and medulla. Finally, matrix protein (type IV collagen, fibronectin) expression was also dose- dependently reduced by rosuvastatin.CONCLUSION:Our findings indicate that rosuvastatin dose- dependently ameliorates angiotensin II-induced-organ damage and almost completely prevents inflammation at the highest dose. The data implicate 3-hydroxy-3-methylglutaryl coenzyme A function in signaling events leading to target-organ damage.

Mineralocorticoid receptor blockade protects from angiotensin II-induced target-organ damage. 11beta-Hydroxysteroid dehydrogenase type 2 protects the mineralocorticoid receptor from activation by glucocorticoids; however, high glucocorticoid concentrations and absent 11beta-hydroxysteroid dehydrogenase type 2 in some tissues make glucocorticoids highly relevant mineralocorticoid receptor ligands. We investigated the effects of corticosterone (10(-6) to 10(-12) mol/L) on early vascular mineralocorticoid receptor signaling by Western blotting, confocal microscopy, and myography. Corticosterone initiated extracellular signal-regulated kinase 1/2 phosphorylation in rat vascular smooth muscle cells at > or =10(-11) mol/L doses. Protein synthesis inhibitors had no effect, indicating a nongenomic action. Corticosterone also stimulated c-Jun N-terminal kinase, p38, Src, and Akt phosphorylation at 15 minutes and enhanced angiotensin II-induced signaling at 5 minutes. A specific epidermal growth factor receptor blocker, AG1478, as well as the Src inhibitor PP2, markedly reduced corticosterone-induced extracellular signal-regulated kinase 1/2 phosphorylation, as did preincubation of cells with the mineralocorticoid receptor antagonist spironolactone. Silencing mineralocorticoid receptor with small interfering RNA abolished corticosterone-induced effects. Corticosterone (10(-9) mol/L) enhanced phenylephrine-induced contraction of intact aortic rings. These effects were dependent on the intact endothelium, mineralocorticoid receptor, and mitogen-activated protein kinase kinase 1/extracellular signal-regulated kinase signaling. We conclude that corticosterone induces rapid mineralocorticoid receptor signaling in vascular smooth muscle cells that involves mitogen-activated protein kinase kinase/extracellular signal-regulated kinase-dependent pathways. These new mineralocorticoid receptor-dependent signaling pathways suggest that glucocorticoids may contribute to vascular disease via mineralocorticoid receptor signaling, independent of circulating aldosterone.