Blockade of endothelin receptors mitigates SARS-CoV-2-induced osteoarthritis.

Joint pain and osteoarthritis can occur as coronavirus disease 2019 (COVID-19) sequelae after infection. However, little is known about the damage to articular cartilage. Here we illustrate knee joint damage after wild-type, Delta and Omicron variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in vivo. Rapid joint injury with cystic lesions at the osteochondral junction was observed in two patients with post-COVID osteoarthritis and recapitulated in a golden Syrian hamster model. SARS-CoV-2-activated endothelin-1 signalling increased vascular permeability and caused viral spike proteins leakage into the subchondral bone. Osteoclast activation, chondrocyte dropout and cyst formation were confirmed histologically. The US Food and Drug Administration-approved endothelin receptor antagonist, macitentan, mitigated cystic lesions and preserved chondrocyte number in the acute phase of viral infection in hamsters. Delayed macitentan treatment at post-acute infection phase alleviated chondrocyte senescence and restored subchondral bone loss. It is worth noting that it could also attenuate viral spike-induced joint pain. Our work suggests endothelin receptor blockade as a novel therapeutic strategy for post-COVID arthritis.

Early Addition of Selexipag to Double Therapy for Pulmonary Arterial Hypertension.

Importance: A subgroup analysis of a randomized clinical trial established the efficacy of selexipag plus background therapy (monotherapy or double oral therapy [DOT]) vs placebo plus background therapy and found that the addition of selexipag within 6 months had an added benefit. However, the timing of selexipag addition to DOT and the incremental benefit in clinical practice is not well studied. Objective: To compare triple oral therapy (TOT) consisting of selexipag, endothelin receptor antagonist (ERA), and phosphodiesterase type 5 inhibitor (PDE5i) vs DOT consisting of ERA and PDE5i. Design, Setting, and Participants: This comparative effectiveness study was conducted using data from the US Komodo claims database to emulate a randomized trial. Patients aged 18 years or older with pulmonary arterial hypertension (PAH) treated with ERA plus PDE5i with records from July 2015 through June 2022 were duplicated to TOT and DOT and artificially censored when observed treatment deviated from assigned treatment. Hypothetical randomization was emulated using inverse probability of treatment weighting, and the study accounted for censoring-induced selection bias using inverse probability of censoring weighting. A pooled logistic model estimated the per-protocol difference between treatment groups. Data were analyzed from November 2022 through July 2023. Interventions: TOT (addition of selexipag within 3, 6, and 12 months of initiating DOT) vs DOT. Main Outcomes and Measures: Adjusted risk of all-cause hospitalization, PAH-related hospitalization, and PAH-related disease progression over a 2-year follow-up. Results: A total of 2966 patients with PAH (mean [SD] age, 54.3 [14.0] years; 2125 female [71.6%]) met eligibility criteria. Adding selexipag within 6 months of ongoing DOT was associated with a reduction in risk for all-cause hospitalization (adjusted hazard ratio [aHR], 0.82; 95% CI, 0.72-0.94), PAH-related hospitalization (aHR, 0.81; 95% CI, 0.70-0.95), and PAH-related progression (aHR, 0.82; 95% CI, 0.70-0.95) vs DOT alone. There were no associations if selexipag was initiated within 12 months for all-cause hospitalization, PAH-related hospitalization, or PAH-related disease progression. The association remained with a greater decrease in risk for disease progression vs DOT for selexipag initiation within 3 months (aHR, 0.74; 95% CI, 0.61-0.90). Conclusions and Relevance: This study found that early selexipag addition to ERA plus PDE5i was associated with a reduction in risk of hospitalization and disease progression. These findings suggest that delays in selexipag initiation likely contribute to suboptimal patient and health system outcomes.

The role of endothelin receptor antagonists in IgA nephropathy.

There is growing evidence of endothelin receptor antagonists (ERAs) in renoprotection in proteinuric kidney disease including IgA nephropathy (IgAN). Here, we review current evidence, including the use of sparsentan, atrasentan and zibotentan in IgAN. Recent trails of combination therapy including SGLT2 inhibitors and ERAs suggest possible benefit in further reduction of proteinuria and reducing ERA fluid-retention side effects although more evidence is needed for clinical applications.

Recent developments in the management of resistant hypertension: focus on endothelin receptor antagonists.

Resistant hypertension is characterized by the inability of guideline-recommended triple combination therapy to control blood pressure (BP) to target. It is associated with a significantly increased risk of adverse outcomes. Despite abundant preclinical evidence supporting the critical role of the endothelin pathway in resistant hypertension (RH), clinical implementation of endothelin antagonists for the treatment of hypertension was hindered by various factors. Recently, the novel dual endothelin-receptor antagonist aprocitentan was tested in individuals with resistant hypertension in the PRECISION trial and provided compelling evidence supporting both short and longer-term safety and clinically meaningful and sustained BP lowering efficacy. These findings resulted in the recent regulatory approval of aprocitentan by the FDA. Aprocitentan may be a particularly useful antihypertensive option for individuals with advanced age, chronic kidney disease, and albuminuria.

What is this article about? Elevated blood pressure that remains uncontrolled despite recommended drug treatment with at least three established medications including a diuretic, also known as resistant hypertension, is a worldwide health concern and leaves many patients at high risk for adverse cardiovascular consequences such as heart attacks, strokes, and chronic kidney disease. While past research suggested the potential utility of endothelin receptor antagonists in managing hypertension, their efficacy remained unconfirmed until recently.What are the results of the PRECISION study? The PRECISION study examined the safety and efficacy of a novel dual endothelin receptor antagonist aprocitentan in individuals with resistant hypertension. The trial demonstrated that aprocitentan effectively lowered blood pressure both with short- and long-term administration and that it had a favorable safety profile.What do the results of the PRECISION study mean? As a direct consequence of the trial findings, aprocitentan is now approved by the US FDA for the treatment of uncontrolled blood pressure. This drug may prove particularly useful in individuals with clinical features known to render elevated blood pressure more difficult to control such as advanced age, chronic kidney disease, and increased levels of protein in their urine.

Removing the FDA's Boxed Hepatotoxicity Warning and Liver Function Testing Requirement for Ambrisentan.

Importance: Endothelin receptor antagonists are first-line therapy for pulmonary arterial hypertension (PAH). The first 2 agents approved in the class, bosentan and ambrisentan, initially carried boxed warnings for hepatotoxicity and required monthly liver function tests (LFTs) as part of a risk evaluation and mitigation strategy (REMS); however, in 2011, as further safety data emerged on ambrisentan, the boxed hepatotoxicity warning and LFT requirements were removed. Objective: To analyze changes in the use of and LFT monitoring for ambrisentan and bosentan after changes to the ambrisentan labeling and REMS. Design, Setting, and Participants: This serial cross-sectional study used data from 3 longitudinal health care insurance claims databases-Medicaid, Optum's deidentified Clinformatics Data Mart, and Merative Marketscan-to perform an interrupted time series analysis of prescription fills and LFTs for patients taking ambrisentan and bosentan. Participants were patients filling prescriptions for ambrisentan and bosentan from July 1, 2007, to December 31, 2018. Data analysis was performed from April 2021 to August 2023. Exposure: Removal of the boxed warning for hepatotoxicity and the REMS LFT monitoring requirements on ambrisentan in March 2011. Main Outcomes and Measures: The primary outcomes were use of ambrisentan (ie, individuals with at least 1 dispensing per 1 000 000 individuals enrolled in the 3 datasets) vs bosentan and LFT monitoring (ie, proportion of initiators with at least 1 ordered test) before initiation and before the first refill. Results: A total of 10 261 patients received a prescription for ambrisentan during the study period (7442 women [72.5%]; mean [SD] age, 52.6 [17.6] years), and 11 159 patients received a prescription for bosentan (7931 women [71.1%]; mean [SD] age, 47.7 [23.7] years). Removal of the ambrisentan boxed hepatotoxicity warning and LFT monitoring requirement was associated with an immediate increase in the use of ambrisentan (1.50 patients per million enrollees; 95% CI, 1.08 to 1.92 patients per million enrollees) but no significant change in the use of bosentan. There were reductions in recorded LFTs before drug initiation (13.1% absolute decrease; 95% CI, -18.2% to -8.0%) and before the first refill (26.4% absolute decrease; 95% CI, -34.4% to -18.5%) of ambrisentan but not bosentan. Conclusions and Relevance: In this serial cross-sectional study of ambrisentan, labeling changes and removal of the REMS-related LFT requirement were associated with shifts in prescribing and testing behavior for ambrisentan but not bosentan. Further clinician education may be needed to maximize the benefits of REMS programs and labeling warnings designed to ensure the safe administration of high-risk medications.

Effects of Bosentan on Hypoxia, Inflammation and Oxidative Stress in Experimental Blunt Thoracic Trauma Model.

Background and Objectives: In this study, we aimed to investigate the effects of bosentan, an endothelin receptor antagonist, on endothelin-1 (ET-1), hypoxia-inducible factor-1 (HIF-1), nuclear factor-kappa B (NF-κB), and tumor necrosis factor (TNF)-α as inflammation markers, pro-oxidant antioxidant balance (PAB), and total antioxidant capacity (TAC) levels as oxidative stress parameters in lung tissues of rats in an experimental model of pulmonary contusion (PC) induced by blunt thoracic trauma. Materials and Methods: Thirty-seven male Sprague-Dawley rats were divided into five groups. C: The control group (n = 6) consisted of unprocessed and untreated rats. PC3 (n = 8) underwent 3 days of PC. PC-B3 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 3 days. The PC7 group (n = 7) underwent 7 days of PC, and PC-B7 (n = 8) received 100 mg/kg bosentan and was given orally once a day for 7 days. Results: ET-1, NF-κB, TNF-α, HIF-1α, and PAB levels were higher, while TAC activity was lower in all groups compared with the control (p < 0.05). There was no significant difference in ET-1 and TNF-α levels between the PC-B3 and PC-B7 groups and the control group (p < 0.05), while NF-κB, HIF-1α, and PAB levels were still higher in both the PC-B3 and PC-B7 groups than in the control group. Bosentan decreased ET-1, NF-κB, TNF-α, HIF-1α, and PAB and increased TAC levels in comparison to the nontreated groups (p < 0.05). Conclusions: Bosentan decreased the severity of oxidative stress in the lungs and reduced the inflammatory reaction in rats with PC induced by blunt thoracic trauma. This suggests that bosentan may have protective effects on lung injury mechanisms by reducing hypoxia, inflammation, and oxidative stress. If supported by similar studies, bosentan can be used in both pulmonary and emergency clinics to reduce ischemic complications, inflammation, and oxidative stress in some diseases that may be accompanied by ischemia.

A review of novel endothelin antagonists and overview of non-steroidal mineralocorticoid antagonists for treating resistant hypertension: An update.

Several agents are emerging from five different novel classes of antihypertensive medications. We will focus on endothelin antagonists and non-steroidal mineralocorticoid receptor antagonists. While several agents exist in this later class, only a couple have demonstrated superior efficacy in resistant hypertension management. Endothelin receptor antagonists are effective therapy for primary and resistant hypertension, but they are not widely used. This is due to side effects demonstrated in large clinical trials, specifically increased peripheral edema and worsening heart failure in some cases, as well as the availability of many alternative agents to manage blood pressure effectively. However, the relationship between endothelin and its close ties to hypertension is evolving. Recent pre-clinical work explores new applications of more selective endothelin receptor antagonists. They suggest that specific subtypes of hypertension may benefit more from endothelin receptor blockade than simply those with primary hypertension. We review this topic and other related data. Lastly, we also provide a brief overview of non-steroidal mineralocorticoid receptor antagonists as some in the class show promise as antihypertensive agents.

The Anti-Atherosclerotic Effects of Endothelin Receptor Antagonist, Bosentan, in Combination with Atorvastatin-An Experimental Study.

Bosentan, an endothelin receptor antagonist (ERA), has potential anti-atherosclerotic properties. We investigated the complementary effects of bosentan and atorvastatin on the progression and composition of the atherosclerotic lesions in diabetic mice. Forty-eight male ApoE-/- mice were fed high-fat diet (HFD) for 14 weeks. At week 8, diabetes was induced with streptozotocin, and mice were randomized into four groups: (1) control/COG: no intervention; (2) ΒOG: bosentan 100 mg/kg/day per os; (3) ATG: atorvastatin 20 mg/kg/day per os; and (4) BO + ATG: combined administration of bosentan and atorvastatin. The intra-plaque contents of collagen, elastin, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), matrix metalloproteinases (MMP-2, -3, -9), and TIMP-1 were determined. The percentage of lumen stenosis was significantly lower across all treated groups: BOG: 19.5 ± 2.2%, ATG: 12.8 ± 4.8%, and BO + ATG: 9.1 ± 2.7% compared to controls (24.6 ± 4.8%, p < 0.001). The administration of both atorvastatin and bosentan resulted in significantly higher collagen content and thicker fibrous cap versus COG (p < 0.01). All intervention groups showed lower relative intra-plaque concentrations of MCP-1, MMP-3, and MMP-9 and a higher TIMP-1concentration compared to COG (p < 0.001). Importantly, latter parameters presented lower levels when bosentan was combined with atorvastatin compared to COG (p < 0.05). Bosentan treatment in diabetic, atherosclerotic ApoE-/- mice delayed the atherosclerosis progression and enhanced plaques' stability, showing modest but additive effects with atorvastatin, which are promising in atherosclerotic cardiovascular diseases.

Targeting the endothelium by combining endothelin-1 antagonism and SGLT-2 inhibition: better together?

Endothelin A and B receptors, together with sodium-glucose cotransporter-2 (SGLT-2) channels are important targets in improving endothelial function and intervention with inhibitors has been the subject of multiple mechanistic and clinical outcome trials over recent years. Notable successes include the treatment of pulmonary hypertension with endothelin receptor antagonists, and the treatment of heart failure and chronic kidney disease with SGLT-2 inhibitors. With distinct and complementary mechanisms, in this review, we explore the logic of combination therapy for a number of diseases which have endothelial dysfunction at their heart.

[New therapeutic targets in hypertension]. / Nuevas dianas terapéuticas en hipertensión.

Even though a large number of antihypertensive drugs are suitable for hypertension treatment, some new therapeutic targets are recently under development. Most are focused in the treatment of resistant hypertension, added to the drugs currently available for treating such condition. Others have specific particularities in their duration of action, which allows their use once per month or every six months and could become alternatives to the current antihypertensive treatment. Most interesting therapeutic targets are the renin-angiotensin-aldosterone system, through interference with the RNA of the angiotensinogen, the inhibition of brain aminopeptidase III, the inhibition of aldosterone synthase, and new non-steroidal aldosterone receptor antagonists. In addition, dual endothelin receptor antagonists or agonists of the NPR1 receptor, the main effector of natriuretic peptides are other new interesting therapeutic possibilities. In this paper, we review clinical data on the development of the most interesting molecules acting through these new therapeutic targets.

Therapeutic approaches for pulmonary hypertension in patients with chronic kidney disease.

PURPOSE OF REVIEW: Pulmonary hypertension is a common comorbidity in patients with chronic kidney disease (CKD), but therapeutic options are limited. We discuss the epidemiology of pulmonary hypertension in patients with CKD and review therapies for pulmonary hypertension with a focus on emerging treatments for pulmonary arterial hypertension (PAH). RECENT FINDINGS: The definition of pulmonary hypertension has been updated to a lower threshold of mean pulmonary artery pressures of more than 20 mmHg, potentially leading to more patients with CKD to qualify for the diagnosis of pulmonary hypertension. Endothelin receptor antagonists, a class of medications, which demonstrated efficacy in patients with PAH, have been shown to slow progression of CKD, but their efficacy in lowering pulmonary artery pressures and their effects on reducing cardiovascular mortality in this population remains unproven. Sotatercept, a novel activin signaling inhibitor, which was previously studied in dialysis patients has been shown to increase exercise capacity in patients with PAH. These studies may lead to new specific therapies for pulmonary hypertension in patients with CKD. SUMMARY: Pulmonary hypertension is common in patients with CKD. Although our understanding of factors leading to pulmonary hypertension in this population have evolved, evidence supporting disease-specific therapy in CKD is limited arguing for larger, long-term studies.

Aprocitentan: First Approval.

Aprocitentan (TRYVIO™) is a once-daily oral dual endothelin A (ETA) and B (ETB) receptor antagonist developed by Idorsia Pharmaceuticals for the treatment of hypertension. The endothelin pathway has been implicated in hypertension. Aprocitentan inhibits the binding of endothelin-1 to ETA and ETB receptors, thereby preventing its deleterious effects and lowering blood pressure. In March 2024, aprocitentan received its first approval in the USA for the treatment of hypertension in combination with other antihypertensive drugs, to lower blood pressure in adults who are not adequately controlled on other drugs. This article summarizes the milestones in the development of aprocitentan leading to this first approval for hypertension not adequately controlled on other drugs.

Revisiting Hypertension Treatment in Patients With Chronic Kidney Disease.

Despite being the world's top risk factor for death and disability, hypertension awareness and control within the chronic kidney disease (CKD) population have decreased. This is particularly important considering the heightened severity and management challenges of hypertension in CKD patients, whose outcomes are often worse compared with persons with normal kidney function. Therefore, finding novel therapeutics to improve blood pressure control within this vulnerable group is paramount. Although medications that target the renin-angiotensin-aldosterone system remain a mainstay for blood pressure control in most stages of CKD, we discuss novel approaches that may expand their use in advanced CKD. We also review newer tools for blood pressure management that have emerged in recent years, including aldosterone synthase inhibitors, endothelin receptor antagonists, and renal denervation. Overall, the future of hypertension management in CKD appears brighter, with a growing arsenal of tools and a deeper understanding of this complex disease.

Is endothelin targeting finally ready for prime time?

The endothelin family of peptides has long been recognized as a physiological regulator of diverse biological functions and mechanistically involved in various disease states, encompassing, among others, the cardiovascular system, the kidney, and the nervous system. Pharmacological blockade of the endothelin system, however, has encountered strong obstacles in its entry into the clinical mainstream, having obtained only a few proven indications until recently. This translational gap has been attributable predominantly to the relevant side effects associated with endothelin receptor antagonism (ERA), particularly fluid retention. Of recent, however, an expanding understanding of the pathophysiological processes involving endothelin, in conjunction with the development of new antagonists of endothelin receptors or adjustment of their doses, has driven a flourish of new clinical trials. The favorable results of some of them have extended the proven indications for ET targeting to a variety of clinical conditions, including resistant arterial hypertension and glomerulopathies. In addition, on the ground of strong preclinical evidence, other studies are ongoing to test the potential benefits of ERA in combination with other treatments, such as sodium-glucose co-transporter 2 inhibition in fluid retentive states or anti-cancer therapies in solid tumors. Furthermore, antibodies providing long-term blockade of endothelin receptors are under testing to overcome the short half-life of most small molecule endothelin antagonists. These efforts may yet bring new life to the translation of endothelin targeting strategies in clinical practice.

Comparative Effectiveness of Sotatercept and Approved Add-On Pulmonary Arterial Hypertension Therapies: A Systematic Review and Network Meta-Analysis.

Background: There are no direct comparisons of sotatercept to add-on therapies approved for pulmonary arterial hypertension (PAH). Objective: This study aimed to compare the efficacy and safety of add-on sotatercept versus other add-on therapies using a network meta-analysis. Data Sources: We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and clinicaltrials.gov until April 15, 2023, for randomized trials involving patients with PAH who were treated with add-on sotatercept or other add-on PAH therapies. Data Extraction: Data extraction and risk-of-bias assessments were performed independently and in duplicate using the Cochrane RoB 2.0 tool. We performed a frequentist random-effects network meta-analysis using the restricted maximum-likelihood estimator and assessed the certainty of evidence using the GRADE (grading of recommendations assessment development, and evaluation) approach. Synthesis: Our search found 18 trials (5,777 patients) eligible for analysis. Sotatercept reduces clinical worsening as compared with placebo (relative risk [RR], 0.21; 95% confidence interval [CI] = 0.11-0.41; with high certainty). Sotatercept probably reduces clinical worsening more, compared with add-on endothelin receptor antagonists (RR, 0.28; 95% CI = 0.14-0.55), inhaled prostanoid (RR, 40.21; 95% CI = 0.07-0.67), and prostanoid taken orally (RR, 0.32; 95% CI = 0.16-0.67; all with moderate certainty). Sotatercept probably improves 6-minute-walk distance compared with placebo (mean difference [MD], 36.89 m; 95% CI = 25.26-48.51). Although sotatercept probably improves 6-minute-walk distance more than add-on endothelin receptor antagonists (MD, 18.38 m; 95% CI = 5.92-30.84) and prostanoid taken orally (MD, 25.66 m; 95% CI = 13.71-37.61), it did not exceed the minimal clinically important difference of 33 m (both with moderate certainty). Conclusions: Sotatercept is an effective add-on therapy for PAH, likely superior to many approved add-on PAH therapies in reducing clinical worsening.

Bosentan effect on echocardiographic systolic pulmonary arterial pressure in systemic sclerosis-related pulmonary hypertension: a systematic review and metanalysis.

OBJECTIVES: Bosentan is a dual endothelin receptor antagonist approved for the treatment of SSc digital ulcers (DU) and pulmonary arterial hypertension (PAH). Systolic pulmonary arterial pressure (sPAP) is a relevant parameter for the follow-up and prognosis of SSc-PAH. The therapeutic magnitude of bosentan in SSc-PAH is not fully understood, thus we aim to establish the degree of sPAP reduction in bosentan treated SSc-PAH patients. METHODS: We performed a systematic literature review in three databases from January 2000 to June 2023, involving sPAP measurement at transthoracic echocardiography of SSc patients before and after starting bosentan. Following the study quality assessment and data extraction, we performed random-effects meta-analysis and Egger's test for publication bias. Stratified analysis was performed for mono-/combination therapy, follow up duration (≤1 year), indication for bosentan therapy (PAH or DU/mixed). RESULTS: In the 11 selected manuscripts, sPAP mean difference before and after bosentan therapy was - 5.63mmHg (CI95% -9.79 to -1.48, p=0.0078). In stratified analysis, sPAP mean was significantly different before and after bosentan therapy only for studies considering < 1 year of follow-up (p=0.0020), monotherapy (p=0.0140) and the strict indication for PAH (p=0.0002). CONCLUSIONS: Bosentan significantly decreases sPAP, a relevant prognostic marker, especially in overt SSc-PAH. However, bosentan did not decrease sPAP when started for DU/mixed indication nor for follow-up>1 year. The burden of publication bias was significant. Therefore, further studies are required to assess bosentan's haemodynamic effect in high-risk patients for SSc-PAH.

Effectiveness of a Prostacyclin IP Receptor Agonist in Patients With Pulmonary Arterial Hypertension in the Real-world Andalusian Setting: The RAMPHA Study.

PURPOSE: The pillar for therapeutic decisions in the evolution of pulmonary arterial hypertension (PAH) is the patients' prognostic stratification. METHODS: A retrospective cohort study was conducted in a Spanish real-world setting to assess the clinical improvement of PAH patients treated with selexipag measured as changes in the risk profile. Secondary objectives were to describe their baseline characteristics, initial risk status, and variables used to assess patient survival and adverse events. FINDINGS: Total 42 patients (mean age 52.36 [SD: 15.09] years) were included. All had received initial endothelin receptor antagonist treatment and 95.2% dual therapy with phosphodiesterase-5 inhibitor or riociguat. At 6 to 12 months from baseline, patients risk stratification tripled the percentage of patients with low risk, and a trend towards improved risk stratification (P = 0.122). World Health Organization functional class changed, with more patients in milder classes (P = 0.003), and symptom progression slowed down (P < 0.0001). At 3-years, survival was 85.7% and the estimated median survival time was 2.73 years (SD: 1.351; 95% CI: 2.51-2.95). IMPLICATIONS: Selexipag did not achieve a significant improvement in risk profile, although it did show an excellent survival rate, effectively improved functional class, and delayed symptom progression in real life. Selexipag was well tolerated and showed a favorable safety profile, supporting a clinical benefit for PAH patients.