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This open-label, extension study assessed long-term safety, tolerability, and efficacy of ambrisentan in a pediatric population (age 8– < 18 years) with pulmonary arterial hypertension (PAH). Following completion of a 6-month, randomized study, participants entered the long-term extension at individualized ambrisentan dosages (2.5/5/7.5 or 10 mg/day). Safety assessments included adverse events (AEs), AEs of special interest, and serious AEs (SAEs); efficacy outcomes included 6-min walking distance (6MWD) and World Health Organization functional class (WHO FC). Thirty-eight of 41 (93%) randomized study participants entered the extension; 21 (55%) completed (reaching age 18 years). Most participants received concomitant phosphodiesterase-5 inhibitors (n = 25/38, 66%). Median ambrisentan exposure was 3.5 years. Most participants experienced ≥ 1 AE (n = 34/38, 89%), and 21 (55%) experienced SAEs, most commonly worsening PAH (n = 3/38, 8%), acute cardiac failure, pneumonia, or anemia (n = 2/38; 5% each); none considered ambrisentan-related. Seven participants (18%) died, with recorded reasons (MedDRA preferred term): cardiac failure (n = 2), PAH (n = 2), COVID-19 (n = 1), acute right ventricular failure (n = 1), and failure to thrive (n = 1); median time to death: 5.2 years. Anemia and hepatotoxicity AEs were generally mild to moderate and did not require ambrisentan dose adjustment. Assessed at study end in 29 participants (76%), mean 6MWD improved by 17% (standard deviation: 34.3%), and all (29/29, 100%) had improved or unchanged WHO FC. Conclusion: Long-term weight-based ambrisentan dosing, alone or combined with other PAH therapies in children with PAH aged 8– < 18 years, exhibited tolerability and clinical improvements consistent with prior randomized study results. Trial registration: NCT01342952, April 27, 2011. What is Known: •The endothelin receptor antagonist, ambrisentan, is indicated for treatment of pulmonary arterial hypertension (PAH). Previous studies have shown similar efficacy and tolerability in pediatric patients as in adults. What is New: • This open-label extension study assessed the long-term use of ambrisentan in pediatric patients (8–<18 years) with PAH, most of whom were also receiving recommended background PAH treatment. • Weight-based dosing of ambrisentan, given alone or in combination with other PAH therapies, was well tolerated with clinical improvements consistent with prior randomized study results. [ABSTRACT FROM AUTHOR]

Purpose of Review: To provide an update and review approaches to the treatment of resistant hypertension (RH) with a focus on emerging potential therapies. Recent Findings: Resistant hypertension is defined as a blood pressure that remains elevated above a patient's individualized target despite the concurrent use of 3 antihypertensive agents of different classes including a diuretic or use of 4 or more antihypertensive agents. Patients with RH have an increased risk of adverse cardiovascular and renal outcomes. Most RH is attributed to apparent RH and is not true RH. True RH is a diagnosis of exclusion after apparent RH has been excluded. Treatment of RH is challenging, and blood pressure goal is often difficult to achieve. Currently several new therapies have emerged with forthcoming data that provide promise for improved blood pressure control in those with resistant hypertension. Summary: Once RH has been diagnosed, patients should be on standardized therapy that includes agents from three different classes including a diuretic with addition in most cases of a mineralocorticoid as a fourth line agent. There are newer agents in development currently being studied in clinical trials including dual endothelin receptor antagonists and aldosterone synthase inhibitors that appear to be efficacious. Other approved medications including SGLT2 inhibitors and non-steroidal mineralocorticoids such as finerenone also need to be incorporated into treatment paradigms. Renal denervation with catheter based devices is another potential promising treatment option in this population. [ABSTRACT FROM AUTHOR]

Purpose of Review: Resistant hypertension (RH) defined as uncontrolled blood pressure despite the use of a combination of a renin-angiotensin system blocker, a calcium channel blocker, and a diuretic at maximally tolerated doses is associated with a substantially increased risk of cardiovascular and renal events. Despite targeting relevant pathophysiological pathways contributing to elevated blood pressure, approximately 10–15% of hypertensive patients remain above recommended blood pressure targets. Further optimization of blood pressure control is particularly challenging in patient populations who frequently present with RH such as elderly and patients with chronic kidney disease, due to the unfavorable safety profile of the recommended fourth-line therapy with mineralocorticoid receptor antagonists. This review explores the potential role of endothelin antagonists as an alternative fourth-line therapy. Recent Findings: Despite the well-described role of the endothelin pathway in the pathogenesis of hypertension, it is currently not targeted therapeutically. Recently however, main outcome data from the PRECISION study, a randomized placebo-controlled phase 3 trial, in patients with RH on guideline-recommended standardized single-pill background therapy convincingly demonstrated the safety and blood pressure-lowering efficacy of the dual endothelin antagonist Aprocitentan. Summary: Findings from the phase 3 PRECISION study could signify a turning point in the utilization of endothelin receptor antagonists as a standard treatment for patients with RH. [ABSTRACT FROM AUTHOR]

Sickle cell disease (SCD), a haemoglobinopathy characterized by chronic haemolysis with acute exacerbations and vascular occlusion episodes, may be complicated by pulmonary hypertension. The latter may be caused by chronic thromboembolic disease of pulmonary artery branches and its management is not well-defined. Herein, we present a case of SCD complicated by chronic thromboembolic pulmonary hypertension of subsegmental pulmonary artery branches successfully treated with endothelin receptor antagonists, orally administered prostacyclin analogs and balloon pulmonary angioplasty. This challenging case highlights the need for clinical awareness of chronic thromboembolic pulmonary hypertension as a specific and potentially curable form of pulmonary hypertension complicating SCD course that may necessitate combined pharmacologic and interventional management. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is the main cause of end-stage renal disease worldwide arising as a frequent complication of diabetes, obesity, and hypertension. Current therapeutic options, mainly based of inhibition of the renin-angiotensin system (RAS), provide imperfect renoprotection if started at an advanced phase of the disease, and treatments that show or even reverse the progression of CKD are needed. The endothelin (ET) system contributes to the normal renal physiology; however, robust evidence suggests a key role of ET-1 and its cognate receptors, in the progression of CKD. The effectiveness of ET receptor antagonists in ameliorating renal hemodynamics and fibrosis has been largely demonstrated in different experimental models. A significant antiproteinuric effect of ET receptor antagonists has been found in diabetic and non-diabetic CKD patients even on top of RAS blockade, and emerging evidence from ongoing clinical trials highlights their beneficial effects on a wide range of kidney disorders. [ABSTRACT FROM AUTHOR]

Background: Patients with pulmonary arterial hypertension (PAH) and distal chronic thromboembolic pulmonary hypertension (CTEPH) who still reveal risk factors of worse prognosis on double combination therapy may benefit from add-on therapy with the novel oral selective prostacyclin receptor agonist selexipag. Methods: We reviewed all patients with PAH/distal CTEPH in the Zurich cohort who received selexipag as add-on to oral combination therapy and retrieved New York Heart Association (NYHA) functional class, 6-min walk distance (6MWD), NT-pro-BNP, quality of life questionnaires (CAMPHOR and EuroQoL), tricuspid pressure gradient (TPG) by echocardiography and cardiopulmonary exercise test parameters (power output and oxygen uptake). Results: Twenty-three patients with PAH/CTEPH (20/3), 14 females, median (quartiles) age 56 (46; 66) years received an oral triple therapy containing selexipag at a median dose of 2000 (1600; 3100) mcg during 221 (113; 359) days. The following parameters were stabilized from baseline to last FU: 6MWD (440 (420; 490) to 464 (420; 526) m), NYHA class (three to two), NT-pro-BNP (326 (167; 1725) to 568 (135; 1856) ng/l), TPG, power output, and oxygen uptake. Quality of life reflected by the CAMPHOR and EuroQoL improved. Conclusions: Early initiation of triple oral combination therapy including selexipag in PAH/CTEPH with intermediate risk factor profile may help to stabilize functional class, exercise performance, and pulmonary hemodynamics in a real-life setting and potentially improves quality of life. Whether these beneficial effects can be truly attributed to the addition of selexipag should be addressed in future randomized controlled trials. [ABSTRACT FROM AUTHOR]

Purpose: Treatment of pulmonary arterial hypertension (PAH) by vasodilator drug monotherapy is often limited in its effectiveness. Combination therapy may help to improve treatment and to reduce drug toxicity. This study assessed the combination of the endothelin receptor antagonist macitentan and the phosphodiesterase-5 inhibitor vardenafil in a human ex vivo model. Methods: Study patients did not suffer from PAH. Human pulmonary arteries (PA) and veins (PV) were harvested from resected pulmonary lobes. Contractile forces of blood vessel segments in the presence and absence of the vasodilator drugs macitentan, its main metabolite ACT-132577, and vardenafil were determined isometrically in an organ bath. Results: Macitentan 1E-7 M was sufficient to significantly abate endothelin-1-induced vasoconstriction in PA. A concentration of 1E-6 M was required for significant effects of macitentan on PV and of ACT-132577 on both vessel types. Combination of 1E-7 M macitentan and 1E-6 M vardenafil inhibited sequential constriction with endothelin-1 and norepinephrine of PA significantly more than either compound alone. Effects of 3E-7 M and 1E-6 M macitentan and effects of all doses of ACT-132577 were not further enhanced by 1E-6 M vardenafil. Conclusions: These data suggest that vasodilator effects of macitentan and vardenafil combined may surpass monotherapy in vivo if drug doses are adjusted properly. Vasodilation by the longer-acting metabolite ACT-132577 was not further enhanced by vardenafil. [ABSTRACT FROM AUTHOR]

Introduction: A number of studies indicate that endothelin-1 (ET-1) may act as an inflammatory cell “gatekeeper," by regulating the influx of neutrophils following pulmonary injury. To further examine the role of ET-1 in modulating lung inflammation, hamsters were treated with an endothelin receptor antagonist (ERA), HJP272, either 1 h prior to intratracheal instillation of amiodarone (AM) or 24 h afterwards.Methods: In both cases, the extent of lung injury and repair was determined by (1) histopathological changes; (2) neutrophil content in bronchoalveolar lavage fluid (BALF); (3) lung collagen content; (4) tumor necrosis factor receptor 1 expression by BALF macrophages; (5) BALF levels of (a) transforming growth factor beta-1, (b) stromal cell-derived factor 1 (commonly referred to as CXCL12), and (c) platelet-derived growth factor BB; (6) alveolar septal cell apoptosis.Results: For each parameter, pretreatment with HJP272 resulted in a significant reduction compared to AM alone, whereas post-treatment was either ineffective or produced only a marginally significant change, suggesting that the course of lung inflammation and repair is programmed at a very early stage.Conclusions: This finding may explain why ERAs are not an effective treatment for human pulmonary fibrosis. Nevertheless, they may be useful as an adjunct to therapeutic regimens involving drugs that have fibrogenic potential. [ABSTRACT FROM AUTHOR]

Abstract: An improved, simple, efficient, and telescoped synthesis of macitentan, an endothelin receptor antagonist, starting from 5-(4-bromophenyl)-4,6-dichloropyrimidine in an overall yield of around 62% is described.Graphical abstract: [ABSTRACT FROM AUTHOR]

Background: We examined the prevalence, prognosis, and effect of endothelin receptor antagonists on survival in end-stage kidney disease patients with idiopathic pre-capillary pulmonary hypertension. Methods: We investigated 1988 end-stage kidney disease patients in Toujinkai Hospital from January 1, 2001 to December 31, 2014. Pulmonary hypertension was screened by symptoms (dyspnea, hypotension, or near syncope) and echocardiography, and diagnosed by computed tomography with enhancement, pulmonary flow scintigraphy, and right heart catheterization. Results: Fifteen patients (67 ± 11 years; 12 women and 3 men) were diagnosed as idiopathic pre-capillary pulmonary hypertension; mean pulmonary arterial pressure, pulmonary vascular resistance, or pulmonary artery wedge pressure were 55 ± 11 mmHg, 7.5 ± 2.9 Woods units, or 12 ± 2 mmHg, respectively. Of the 15 patients, 14 received hemodialysis, and 1 was in a pre-dialysis stage. Patients were followed through December 31, 2015, and 11 died of heart failure; their mean survival time was 26.4 ± 21.0 months. Endothelin receptor antagonists were used for 11 patients, and mean survival times were 57.3 ± 12.1 months in patients with endothelin receptor antagonists and 7.5 ± 2.1 months in those without. In the Kaplan-Meier analysis, heart failure death-free survival rates were higher in patients with endothelin receptor antagonists than in those without ( P < 0.001); 100 versus 25 % at one year and 71 versus 0 % at 3 years. Conclusion: The prognosis of idiopathic pre-capillary pulmonary hypertension seems to be poor in end-stage kidney disease patients. Administration of endothelin receptor antagonists might improve the survival by inhibiting heart failure death. Registration of clinical trials This study was registered to the ClinicalTrials.gov (): protocol identifier, NCT02743091. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) trial has mostly enrolled patients with World Health Organization functional class (WHO FC) III or IV. However, PAH is rapidly progressive in nature even in patients with less severe forms at diagnosis. Following the recent studies in Western population, here we assessed the efficacy of bosentan in Japanese patients with WHO FCII PAH. In this open-label trial, bosentan 125 mg twice daily was administered for 12 weeks in 16 patients, and a hemodynamic evaluation was performed. Treatment was continued for a further 12 weeks, where the effect on exercise capacity was assessed in 13 patients. In 16 patients, mean pulmonary arterial pressure decreased from 40.4 ± 10.4 to 35.6 ± 12.6 mmHg ( p = 0.018) and cardiac index increased from 2.54 ± 0.73 to 2.96 ± 0.82 L/min/m ( p = 0.023). Thus, pulmonary vascular resistance decreased from 792 ± 565 to 598 ± 558 dyn·sec/cm ( p = 0.006). In 13 patients followed up for 24 weeks, 6-min walking distance increased from baseline at Week 12 ( p = 0.003) and Week 24 ( p = 0.011). All patients were mildly symptomatic at baseline with dyspnea index (Borg scale) of 2.50 ± 1.58 and the specific activity scale (SAS) of 5.0 ± 1.4 METs. These values remained unchanged throughout the study. These results suggest that bosentan treatment was beneficial for Japanese patients with WHO FC II PAH and treatment should be started in the early stage of the disease. [ABSTRACT FROM AUTHOR]

Endothelin receptor antagonists (ERAs) have the potential to be a new paradigm in the treatment of chronic kidney disease (CKD). ERAs inhibit the effects of endothelin-1 (ET-1), which is known to promote CKD by causing renal cellular injury, proteinuria, inflammation, fibrosis, and hypertrophy. ERAs have been extensively studied preclinically in models of CKD and now in a large clinical trial to determine their effect on slowing the progression of CKD. Initial clinical trials show promise with regard to ERA effects on reducing proteinuria in patients with diabetic nephropathy (DN) who are already on renin-angiotensin system (RAS) blocking agents. A common side effect of peripheral edema has been consistently reported in clinical trials using ERAs; hence, finding a safe balance between renoprotective actions and side effects needs to be achieved. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension (PAH) is a rare, progressively worsening disease characterized by dysfunction among endothelial and smooth muscle cells within the pulmonary vasculature with a resultant increase in pulmonary vascular resistance, right ventricular maladaptation and failure, and ultimately early death. The three major therapeutic classes of medications available to treat PAH act as either prostacyclin analogs or endothelin receptor antagonists (ERAs) or by increasing local nitric oxide (NO) levels by means of phosphodiesterase type 5 inhibitors. Several recent trials have investigated the use of oral prostanoid therapy, next-generation ERAs, and soluble guanylate cyclase stimulators (to increase NO levels) as well as novel formulations of pre-existing therapies. The goal of this manuscript is to briefly review established therapies and then discuss recent developments and practical considerations in each of the major drug classes. [ABSTRACT FROM AUTHOR]

Introduction: Previous studies from this laboratory indicate that endothelin-1 (ET-1), a potent vasoconstrictor, may play an important role in lipopolysaccharide (LPS)-induced release of neutrophils from the pulmonary microvasculature. To further test this concept, Syrian hamsters were treated with a novel endothelin receptor A (ETA) antagonist (HJP272) prior to intratracheal instillation of LPS. Methods: The effect of HJP272 on the LPS-induced inflammatory reaction was determined by measuring: (1) lung histopathological changes, (2) total neutrophils in bronchoalveolar lavage fluid (BALF), (3) expression of tumor necrosis factor receptor 1 (TNFR1) by BALF macrophages, and (4) alveolar septal cell apoptosis. Results: Treatment with HJP272 significantly reduced each of these parameters during a 24-hr period following LPS instillation, supporting the concept that limiting the activity of ET-1 may reduce the extent of lung injury. This hypothesis was further tested by giving ET-1 prior to LPS instillation, which resulted in a marked enhancement of LPS-induced lung inflammation, as measured by BALF neutrophils and TNFR1-positive macrophages. Furthermore, the increase in neutrophils resulting from treatment with ET-1 was significantly reduced by HJP272, again demonstrating the ability of ETA receptor antagonists to limit the influx of these cells into the lung. Conclusions: These findings suggest a potential therapeutic role for these agents in diseases where neutrophils are a significant cause of lung injury, such as bronchopneumonia, respiratory distress syndrome, and chronic obstructive pulmonary disease. [ABSTRACT FROM AUTHOR]

There is a growing patient population with adult congenital heart disease that needs specialized medical attention and careful long-term evaluation. Pulmonary arterial hypertension (PAH) associated with congenital heart disease (PAH-CHD) is a common late complication, and is associated with increased morbidity and mortality. There are no clear current guidelines for the treatment of PAH-CHD. There are few trials to date investigating PAH treatment specifically in this group of patients. However, the available data seems to demonstrate that with the advent of PAH-targeted therapies, the quality of life, exercise capacity, and outcomes in these patients is improving. In addition, PAH-targeted therapies may be useful in select patients for a combined medical-surgical approach to treatment. Here we discuss the epidemiology and pathophysiology of PAH-CHD, current therapies, and the data supporting their use, and how to evaluate feasibility of late surgical repair. [ABSTRACT FROM AUTHOR]

Over the past 20 years, great progress has been made in the treatment of pulmonary arterial hypertension (PAH). Available therapies target one of three principal pathways: the endothelin (ET), nitric oxide (NO) or the prostacyclin (PGI2) pathway. Evidence shows that current drugs, used either as monotherapy or in different combinations, can improve exercise capacity, clinical symptoms, hemodynamics and even survival in PAH. Unfortunately, the disease remains incurable and the prognosis of the disease is still poor. However, existing and novel potent antiproliferative therapies are being explored, and new agents targeting different and/or additional pathways are likely to become available to clinicians in the near future. Promising candidates include tyrosine kinase antagonists (e.g. imatinib); soluble guanylate cyclase stimulators (riociguat); an oral analog of prostacyclin (selexipag); and a tissue targeting endothelin receptor antagonist (macitentan). Phase II or III trials have either been completed or are underway to evaluate the safety and efficacy of these various therapies. [ABSTRACT FROM AUTHOR]

Right ventricular failure (RVF) is increasingly recognized as a complicating feature of a number of disease states, including pulmonary arterial hypertension (PAH) and advanced heart failure. It not only contributes to symptoms and complicates management, but also dramatically impacts prognosis. In PAH, early disease detection and institution of PAH therapy can prevent or delay RVF. Once established, therapy for RVF focuses on optimizing afterload reduction with PAH therapy, controlling volume, and judiciously using inotropic support when needed. In patients undergoing implantation of a LVAD, preoperative assessment and management of RVF is critical. Risk factors for the development of RVF after LVAD have been described, and may identify a population best managed with biventricular support. Postoperative management of RVF focuses on supportive therapy, judicious use of inotropes and volume management. Ongoing research may yield insights into specific therapies to prevent or reverse RVF. [ABSTRACT FROM AUTHOR]

Copyright of Der Pneumologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

No medical treatment has been established to ameliorate pulmonary hypertension (PH) due to left heart disease. Heart transplantation (HTx) is thus far the definitive therapy for stage D heart failure, but concomitant PH is one of the major risk factors for death after HTx. Recently, implantation of a left ventricular assist device (LVAD) has been reported to improve PH and has become a major bridge tool for HTx. We experienced a rare case with persistent PH even after the implantation of a continuous-flow LVAD. The administration of an endothelin receptor antagonist, bosentan, significantly decreased pulmonary vascular resistance. Combination therapy with LVAD implantation and anti-PH medication may be useful for patients with stage D heart failure complicated with severe PH. [ABSTRACT FROM AUTHOR]

Increased afterload results in 'pathological' cardiac hypertrophy, the most important risk factor for the development of heart failure. Current in vitro models fall short in deciphering the mechanisms of hypertrophy induced by afterload enhancement. The aim of this study was to develop an experimental model that allows investigating the impact of afterload enhancement (AE) on work-performing heart muscles in vitro. Fibrin-based engineered heart tissue (EHT) was cast between two hollow elastic silicone posts in a 24-well cell culture format. After 2 weeks, the posts were reinforced with metal braces, which markedly increased afterload of the spontaneously beating EHTs. Serum-free, triiodothyronine-, and hydrocortisone-supplemented medium conditions were established to prevent undefined serum effects. Control EHTs were handled identically without reinforcement. Endothelin-1 (ET-1)- or phenylephrine (PE)-stimulated EHTs served as positive control for hypertrophy. Cardiomyocytes in EHTs enlarged by 28.4 % under AE and to a similar extent by ET-1- or PE-stimulation (40.6 or 23.6 %), as determined by dystrophin staining. Cardiomyocyte hypertrophy was accompanied by activation of the fetal gene program, increased glucose consumption, and increased mRNA levels and extracellular deposition of collagen-1. Importantly, afterload-enhanced EHTs exhibited reduced contractile force and impaired diastolic relaxation directly after release of the metal braces. These deleterious effects of afterload enhancement were preventable by endothelin-A, but not endothelin-B receptor blockade. Sustained afterload enhancement of EHTs alone is sufficient to induce pathological cardiac remodeling with reduced contractile function and increased glucose consumption. The model will be useful to investigate novel therapeutic approaches in a simple and fast manner. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of tezosentan, a parenteral dual ET receptor antagonist, on splanchnic and systemic hemodynamics in patients with cirrhosis. In addition, the safety, pharmacokinetics, and pharmacodynamics of tezosentan were evaluated. Methods: The population consisted of patients with cirrhosis with clinically significant portal hypertension. This was a randomized, double-blind, multicenter study. The patients were randomized 3:1 to tezosentan (3 mg/h for 2-3 h) or placebo. HVPG, hepatic blood flow (HBF, ICG method), and systemic arterial pressures were measured before and after tezosentan administration. Plasma concentrations of tezosentan and ET-1 were determined peripherally and in the hepatic vein. Results: Eighteen patients received tezosentan and six placebo. Baseline clinical, biochemical, and hemodynamic characteristics were balanced between the two groups. There was no significant treatment effect on HVPG. The extraction ratio (0.31), the plasma clearance of ICG (280 ml/min), and the HBF (1,430 ml/min) did not show any relevant changes during the infusion of tezosentan, and there were no differences between placebo- and tezosentan-treated patients. A linear relationship was observed between the maximum-fold increase in ET-1 concentration and the steady-state tezosentan plasma concentration ( r = 0.82). There was a strong correlation ( r = 0.88) between plasma clearance of ICG and that of tezosentan (10.2 l/h). Arterial pressure and heart rate did not significantly change in either group. Conclusion: In patients with cirrhosis, a 2- to 3-h tezosentan infusion was safe and well tolerated but did not change the HVPG. Tezosentan infusion had no influence on the extraction ratio and plasma clearance of ICG and did not change HBF. [ABSTRACT FROM AUTHOR]

Aims/hypothesis: Endothelial dysfunction is important in the development of vascular complications in diabetes. Patients with type 2 diabetes have increased production of the vasoconstrictor and pro-inflammatory peptide, endothelin-1. Short-term intra-arterial administration of endothelin antagonists improves endothelium-dependent vasodilatation in patients with type 2 diabetes. We tested the hypothesis that oral administration of the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria. Methods: This placebo-controlled and double-blind study was performed on 46 patients with type 2 diabetes and microalbuminuria (urine albumin/creatinine ratio >3 mg/mmol) at a medical university department. Patients were randomised to bosentan, 125 mg two times per day ( n = 28), or placebo ( n = 28) for 4 weeks. The computer-generated randomisation code was kept in sealed envelopes. Patients and people doing examinations or assessing outcomes were blinded. The primary endpoint was change in microvascular endothelium-dependent vasodilatation, based on change in digital reactive hyperaemia index. The secondary endpoint was change in brachial artery flow-mediated vasodilatation. Results: Reactive hyperaemia index increased from 1.73 ± 0.43 (mean ± SD) at baseline to 2.08 ± 0.59 at follow-up ( p < 0.05) in the bosentan group ( n = 22), but did not change in the placebo group (1.84 ± 0.49 to 1.87 ± 0.47; n = 24). The change in reactive hyperaemia index from baseline was greater in the bosentan group than in the placebo group ( p < 0.05). Nitroglycerine-induced digital hyperaemia was not affected. Brachial artery flow-mediated vasodilatation and blood pressure did not change during treatment. Conclusions/interpretation: Oral treatment of 4 weeks duration with the dual endothelin receptor antagonist, bosentan, improves peripheral endothelial function in patients with type 2 diabetes and microalbuminuria. Trial Registration:: ClinicalTrial.gov NCT01357109; Karolinska Clinical Trial Registration Identifier CT20090017 (see ) Funding:: Research Council of Sweden, Swedish Heart and Lung Foundation, Novo Nordisk Foundation, Karolinska Institutet/Stockholm County Council Strategic Cardiovascular Programme, Gustav V and Queen Victoria Foundation, the Family Erling Persson Foundation, Actelion Pharmaceuticals and Actelion Research Award. [ABSTRACT FROM AUTHOR]

Pulmonary arterial hypertension associated with scleroderma (SScPAH) is a debilitating, highly lethal condition that responds to an array of therapies. Quality of life and prognosis are substantially improved by treatment, and early diagnosis and treatment are associated with improved outcomes. There are serious limitations to current screening programs. Many more questions need to be addressed. Why is PAH so common in SSc? Why is the tolerance of pulmonary hypertension so poor in scleroderma? What are the best measures of response to therapy in SSc patients with PAH? Should we use different parameters in prognostic scores in SScPAH? Why is postcapillary pulmonary hypertension so common in SSc? How do we reliably differentiate lung disease-associated pulmonary hypertension from PAH? The aim of this review is to summarize the main areas of progress over the past decade and to look to the challenges for the next decade. [ABSTRACT FROM AUTHOR]

Copyright of Der Nephrologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: To study the pharmacokinetics, pharmacodynamics, and tolerability of rising single doses of macitentan, an endothelin receptor antagonist, in healthy male subjects. Methods: This double-blind, placebo-controlled study was performed in seven groups of eight healthy male subjects. Doses of 0.2, 1, 5, 25, 100, 300 and 600 mg or placebo (two subjects per group) were administered. Plasma macitentan and endothelin-1 and serum total bile salt concentrations were measured and analysed non-compartmentally. Plasma and urine were analysed qualitatively for the presence of metabolites and one of these, ACT-132577, was also measured quantitatively in plasma. Standard tolerability measurements were performed throughout the study. Results: Macitentan was slowly absorbed and, at a dose of 300 mg, the t (95% confidence interval, CI) was 17.5 h (14.1, 21.8). The dose-proportionality coefficient β for C (95% CI) was 0.83 (0.79, 0.87) indicating less than dose-proportional pharmacokinetics of macitentan. In plasma, a pharmacologically active oxidative depropyl metabolite, ACT-132577, was found whereas in urine two minor metabolites were detected. The t of ACT-132577 (95% CI) was 65.6 h (53.1, 80.9). Macitentan dose-dependently increased endothelin-1 concentrations up to 2.2-fold (95% CI 1.4, 2.4) at a dose of 600 mg, but had no consistent effect on total bile salts. Macitentan was well tolerated up to and including a dose of 300 mg, the maximum tolerated dose. Headache, nausea and vomiting were dose-limiting adverse events. Conclusion: The pharmacokinetic and tolerability profile of macitentan is consistent with a once-a-day dosing regimen and warrants further investigation in clinical studies. [ABSTRACT FROM AUTHOR]

Copyright of Wiener Klinische Wochenschrift is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary vascular disease with multiple arterial venous malformations. Pulmonary arterial hypertension is occasionally associated with HHT; however, there is no evidence of targeted therapy for this subgroup of patients. This report describes a 37-year-old woman who presented with dyspnea on exertion. She was finally diagnosed with pulmonary arterial hypertension associated with HHT (HHT2, MIM 600376), and had multiple arterial venous malformations in the lung, liver and pancreas. An oral dual endothelin receptor (ET/ET) antagonist, bosentan, was prescribed, and her symptoms, exercise capacity and laboratory findings imporved greatly after treatment. Pulmonary arterial pressure also decreased. Endothelin receptor antagonist is a possible treatment option for pulmonary arterial hypertension associated with HHT. [ABSTRACT FROM AUTHOR]

Approximately one third of patients with sickle cell disease (SCD) have pulmonary hypertension (PH), which increases their risk of death. Endothelin (ET)-1 is elevated in SCD and appears to play a key role in many of the pathologic processes in this disease, including PH, suggesting that endothelin receptor antagonists such as bosentan may be effective in treating patients with SCD, particularly those with PH. Other possible treatments include sildenafil, epoprostenol, and oral arginine. Data from controlled clinical trials are needed to establish the most effective treatment of patients with PH associated with SCD. [ABSTRACT FROM AUTHOR]

Neutrophils isolated from human peripheral blood added to a monolayer of human endothelial cells (ECV-304 cell line) stimulated with LPS (100 ng ml−1) resulted in: (a) neutrophil activation, measured by spreading and release of leukotriene B4 (LTB4); (b) neutrophil degranulation, measured by release of matrix pro-metalloproteinase-9 (proMMP-9) and (c) loss of the monolayer integrity due to detachment of the endothelial cells. Stimulation of endothelial cells with tumor necrosis factor-α (TNF-α 10 ng ml−1) or interleukin-1 (IL-1; 10 ng ml−1) induced a similar dose-dependent increase in the neutrophil activation and endothelial cell detachment. Pre-treatment of LPS-activated ECV-304 cells with [Phe22]BigET-1(19–37) (10−9 M; an inhibitor of endothelin converting enzyme (ECE)) or addition of BQ-123 (10−6 M; a selective endothelin A (ETA) receptor antagonist) to the co-cultures, significantly reduced neutrophil spreading (50–70% inhibition) as well as the levels of LTB4 (70–100% inhibition) and proMMP-9 (40–50% inhibition) in the co-culture supernatants. In addition, the detachment of endothelial cells was also reduced (60–75% inhibition). Moreover, the exogenous addition of ET-1 (10−9 M) to neutrophil suspensions induced neutrophil spreading and release of LTB4 and proMMP-9. Taken together, these findings indicate that neutrophils added to stimulated endothelial cells in the co-culture system employed in this study, get activated by products of these cells and degranulate. In parallel, the detachment of endothelial cell monolayer from the culture plates, possibly by the action of neutrophil granule-derived gelatinases, is observed. Endothelins (ETs) produced by the endothelial cells are suggested to play an essential role in these phenomena. [ABSTRACT FROM AUTHOR]

Aim: To examine whether a novel endothelin receptor antagonist, CPU0213, is effective in relieving the acute renal failure (ARF) of septic shock by suppressing the activated endothelin-reactive oxygen species (ET-ROS) pathway and nuclear factor kappa B (NF-κB). Methods: The cecum was ligated and punctured in rats under anesthesia. CPU0213 (30 mg·kg−1·d−1, bid, sc×3 d) was administered 8 h after surgical operation. Results: In the untreated septic shock group, the mean arterial pressure and survival rate were markedly decreased ( P<0.01), and heart rate, weight index of kidney, serum creatinine and blood urea nitrogen, 24 h urinary protein and creatinine were significantly increased ( P<0.01). The levels of ET-1, total NO synthetase (tNOS), indusible nitric oxide synthetase (iNOS), nitric oxide (NO), and ROS in serum and the renal cortex were markedly increased ( P<0.01). The upregulation of the mRNA levels of preproET-1, endothelin converting enzyme, ETA, ETB, iNOS, and tumor necrosis factor-alpha in the renal cortex was significant ( P<0.01). The protein amount of activated NF-κB was significantly increased ( P<0.01) in comparison with the sham operation group. All of these changes were significantly reversed after CPU0213 administration. Conclusion: Upregulation of the ET signaling pathway and NF-κB play an important role in the ARF of septic shock. Amelioration of renal lesions was achieved by suppressing the ETA and ETB receptors in the renal cortex following CPU0213 medication. [ABSTRACT FROM AUTHOR]

Although either inhaled nitric oxide (NO) or endothelinA receptor antagonist has been tried in the treatment of various forms of pulmonary hypertension, the effects of combination therapy have not been reported. We evaluated the effects of inhaled NO alone or a combination of inhaled NO and ZD2574 (an endothelinA receptor antagonist) in an experimental canine acute pulmonary thromboembolism model. Forty parts per million of inhaled NO alone, or a combination of inhaled NO and 10 mg/kg of ZD2574 was administered 1 hour after embolization with an autologous blood clot. We compared the hemodynamic and gas exchange parameters between the two treatment groups. Two treatment regimens decreased mean pulmonary arterial pressure and pulmonary vascular resistance and attenuated decrease in cardiac output. Moreover, systemic arterial hypotension or worsening of hypoxemia did not occur in either of the treatment groups. In the combined group, more favorable hemodynamic outcomes were maintained than in the inhaled NO alone group. And hemodynamic deterioration shown after NO withdrawal was attenuated in the combined group. These findings suggest that when inhaled NO is concomitantly administered with an ETA receptor antagonist, more favorable hemodynamic outcomes can be expected during and after NO inhalation in acute pulmonary thromboembolism. [ABSTRACT FROM AUTHOR]

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Background and aim. Due to increased capillary permeability and the early appearance of vasoactive and toxic agents, patients suffering from necrotizing pancreatitis frequently develop a systemic inflammatory response syndrome (SIRS). Endothelin, a potent vasoconstrictor, is thought to play a major role in these changes via the regulation of microcirculation. An improved outcome of acute experimental necrotizing pancreatitis by blocking the endothelin receptors ETA and ETB, either selectively (only ETA) or unselectively (ETA and ETB), has been suggested. The aim of this study was to investigate further the beneficial effects of new, highly potent endothelin-receptor (ET-R) antagonists in acute experimental pancreatitis. Methods. The influence of the selective ET-RA antagonist BSF208075 (1 mg/kg) on mortality was studied in three severity groups of acute necrotizing pancreatitis (retrograde injection of 4%, 5% and 6% of sodium taurocholate into the main pancreatic duct). The effects of the selective ET-RA antagonists LU135252 (LU13) and BSF208075 (BSF20) and of the unselective endothelin receptor (ET-RA/B) antagonist BSF420627 (BSF42) were additionally analyzed in 4% taurocholate-induced necrotizing pancreatitis. Furthermore, the significance of variable doses of the endothelin receptor antagonist LU13 (1 mg/kg, 3 mg/kg and 100 mg/kg) was determined in a 4% sodium taurocholate model and in a cerulein pancreatitis model. Results. Prophylactic ET-R antagonism increased the mortality rate in the 4% sodium taurocholate-induced pancreatitis. No reduction in pancreatic damage after induction of taurocholate pancreatitis was found by ET-R blockage. Application of ET-R antagonists had no beneficial influence in ascites development. However, administration of LU13 (100 mg/kg) resulted in a non-significant increase in pancreatic oedema, whereas peritoneal necrosis was not affected. Conclusion. The selective and unselective ET-R antagonists BSF20, BSF42 and LU13 failed to improve survival and pancreatic damage during acute experimental pancreatitis. Therefore, previously reported beneficial effects of ET-R antagonists in experimental acute pancreatitis have to be critically evaluated before conclusions for further clinical development are made. [ABSTRACT FROM AUTHOR]

Endothelin, a potent vasoconstrictor, has been found to increase in the cerebrospinal fluid and serum of patients following subarachnoid hemorrhage (SAH) and to play a major role in the development of cerebral vasospasm. The aim of this study is to investigate the role of endothelin-A antagonist BQ-610 in the experimentally performed cerebral vasospasm following SAH. Thirty New Zealand rabbits were divided into three groups (each n=10): group A, control group; Group B, SAH group; Group C, treatment (endothelin antagonist BQ-610 treated) group. In the study, the rabbits developed vasospasm after injection of intracisternal autolog blood into the cisterna magna. After cerebral vasospasm development, in group C, endothelin antagonist BQ-610 was injected intracisternally. Morphometrically, basilar artery lumen was constricted 25% and 62% compared to the control group (group A) in the endothelin treated group (group C) and the endothelin untreated group (group B), respectively. Histopathological findings of the basilar artery wall confirmed the therapeutic effect of endothelin antagonist in vasospasm development. Endothelin-A receptor antagonist BQ-610 has a therapeutic effect in the cerebral vasospasm following experimentally performed subarachnoid hemorrhage when used intracisternally. [ABSTRACT FROM AUTHOR]

Administration of tumour necrosis factor-α (TNF-α) produces progressive reduction in cardiac output (CO) by affecting preload, afterload and cardiac contractility. We have examined the effect of an endothelin receptor antagonist, tezosentan (1, 3 or 10 mg/kg), on CO, heart rate (HR), blood pressure (BP), mean circulatory filling pressure (Pmcf), resistance to venous return (RVR), arterial resistance (AR), dP/dt, stroke volume (SV), plasma levels of NO2-/NO3-, and inducible nitric oxide synthase (iNOS) activity in lungs, ex vivo, following treatment with TNF-α (30 μg/kg) in anaesthetized rats. Treatment with TNF-α alone resulted in significant reduction in CO (40±4%), dP/dt (24±2%), Pmcf (24±2%), BP (21±3%) and SV (38±5%) (n=6; mean ± SEM), and significant increases in RVR (38±9%) and AR (45±6%). There were no significant changes in HR or in plasma levels of NO2-/NO3- in animals treated with TNF-α but there was a modest but significant increase in iNOS activity. Tezosentan alone did not have any effect on haemodynamics, plasma levels of NO2-/NO3- or iNOS activity. Tezosentan at the highest dose abolished the effects of TNF-α on dP/dt, AR, and RVR. In animals treated with a combination of TNF-α and highest dose of tezosentan CO, Pmcf, BP, and SV were reduced by 28±5%, 16±3%, 21±4%, and 27±5%, respectively. Tezosentan was able to inhibit the negative impact of TNF-α on AR and dP/dt but not on Pmcf. It is likely that the negative impact of TNF-α on CO in tezosentan-treated animals could be entirely attributed to reduction in preload. [ABSTRACT FROM AUTHOR]

Since its discovery in 1988, there has been increasing evidence that endothelin-1 (ET-1) plays an important role in the pathophysiology of hypertension and its related end-organ damages. First studies, using ET-1 administration in animals or in humans suspected this role by demonstrating the hypertensive properties of ET-1. The latter, due to stimulation of ET(A) receptors inducing sustained vasoconstriction have been reported to follow transient vasodilation linked with activation of an endothelial ET(B) receptor releasing nitric oxide (NO). In certain instances, ET(B) smooth-muscle receptors might also induce contraction. Cloning of these receptors helped to develop ET-1 receptor antagonists. As soon as one of them became available, bosentan, a dual (ET(A) and ET(B)) ET-1 receptor antagonist, we tested its effects in the canine model of perinephritic hypertension. Bosentan was found to exert striking hypotensive effects, due to peripheral vasodilation but without affecting cardiac function. In further experiments, we observed that effects of bosentan were additional to those of ACE inhibitors or angiotensin II antagonists. This opened new therapeutic perspectives and also suggested a proper role of ET-1 in hypertension, independent of the renin-angiotensin system. To explain this role, we demonstrated a real imbalance characterized by an impairment of the NO system in favor of the ET-1 pathway. Recent studies suggest that such an imbalance may also occur in human hypertension. Furthermore, the contribution of ET-1 to human hypertension appears more convincing since bosentan was shown to decrease blood pressure in hypertensive subjects. Finally, ET-1 receptor antagonists might be of therapeutic interest to prevent hypertension induced end-organ damages. Whether or not these compounds are able to prevent or to reverse target organ injuries in man remains to be investigated. [ABSTRACT FROM AUTHOR]

Endothelin-1 is a recently discovered peptide mainly released from endothelial cells. Hypoxia and ischemia as well as numerous factors such as angiotensin 11, thrombin and transforming growth factor β stimulate the fomation of the peptide. On the other hand the synthesis of endothelin is inhibited by nitric oxide and atrial natriuretic peptide via the formation of cyclic guanosine monophosphate. Released from endothelial cells endothelin-1 mediates transient vasodilation followed by a profound and longlasting vasoconstriction. Endothelin is also a mitogen for smooth muscle proliferation. Endothelins exert their biological effects via activation of specific receptors. Two different receptors have been cloned from mammalian tissues (ET and ET receptors). On vascular smooth muscle cells both receptors mediate contractions. Endothelial cells only express ET receptors linked to the formation of nitric oxide and/or prostacyclin formation. Increased plasma concentrations of endothelin-1 have been described in a variety of diseases such as pulmonary hypertension, arteriosclerosis, renal failure, acute coronary syndromes, heart failure, migraine and vascular diseases. Recently an increasing number of endothelin receptor antagonists have been synthetized, which have been shown to inhibit endothelin-mediated vasoconstriction. Clinical studies are now ongoing to elucidate the pathophysiologic role of endothelin and the potential benefit of the blockade of the system in different disease states. [ABSTRACT FROM AUTHOR]

3,4-Seco-derivatives of myricerone were prepared by the Baeyer-Villiger oxidation of myricerone, and their structures were elucidated based on NMR and MS analyses. The synthesized compounds were evaluated as endothelin receptor antagonists and exhibited significant binding affinity for the ET receptor. [ABSTRACT FROM AUTHOR]

Agents that indiscriminately block endothelin receptors have been shown to cause moderate improvements in the outcomes of patients who have pulmonary arterial hypertension (PAH) as a complication of connective tissue disease (CTD). Girgis et al. investigated the effects of sitaxsentan, a selective endothelin receptor type A antagonist, in patients with CTD and comcomitant PAH. After 12 weeks of treatment, patients who received sitaxsentan showed more improvement from baseline compared with those receiving placebo in terms of exercise capacity, hemodynamics and physical-health-related quality of life. At the end of the extension study (median total follow-up 26 weeks), 16 of the 41 patients with CTD had an improvement of at least one New York Heart Association functional class compared with at the start of sitaxsentan therapy. The effects of sitaxsentan observed in the CTD group were comparable to those seen in the idiopathic PAH group. The authors concluded that treatment with sitaxsentan might be beneficial in patients with PAH associated with CTD. [ABSTRACT FROM AUTHOR]