Endothelin Receptor Research Articles

Comparative Treatment Persistence and Adherence to Endothelin Receptor Antagonists Among Patients with Pulmonary Arterial Hypertension in Japan: A Real-World Administrative Claims Database Study.

Real-world data on the comparative effectiveness of endothelin receptor antagonists (ERAs; macitentan, bosentan, ambrisentan) for pulmonary arterial hypertension (PAH), particularly in Asian countries, are scarce. We evaluated the persistence of these ERAs before and after macitentan approval in Japan (2015). We used real-world data from the Japanese Medical Data Vision administrative claims database between April 2008 and November 2020. Patients with PAH were identified from the dataset. Persistence to ERA treatment before and after approval of macitentan in Japan was defined as the time between start of the index ERA and treatment discontinuation or death. Propensity score adjustment was applied to minimize confounding effects among treatment groups. In the pre-macitentan approval cohort, 153 and 51 patients received bosentan and ambrisentan, respectively. In the post-macitentan approval cohort, 331, 284, and 91 patients received macitentan, bosentan, and ambrisentan, respectively. Unadjusted median persistence for ambrisentan- and bosentan-treated patients was 19 and 10months, respectively (adjusted HR 0.87 [95%CI 0.61-1.24]; P = 0.434 [bosentan as reference]). In the post-macitentan approval cohort, unadjusted median persistence was 18months for macitentan-treated patients versus 6 and 8months for ambrisentan- and bosentan-treated patients, respectively. Adjusted HRs for ambrisentan and bosentan were 1.48 (95%CI 1.12-1.95; P = 0.006) and 1.63 (95%CI 1.30-2.04; P < 0.001 [macitentan as reference]), respectively. Real-world data for Japanese patients with PAH showed that persistence was significantly higher for macitentan, versus ambrisentan and bosentan, since its approval.

Underlying Mechanisms and Treatment of Hypertension in Glomerular Diseases.

This review aims to explore the underlying mechanisms that lead to hypertension in glomerular diseases and the advancements in treatment strategies and to provide clinicians with valuable insights into the pathophysiological mechanisms and evidence-based therapeutic approaches for managing hypertension in patients with glomerular diseases. In recent years, there have been remarkable advancements in our understanding of the immune and non-immune mechanisms that are involved in the pathogenesis of hypertension in glomerular diseases. Furthermore, this review will encompass the latest data on management strategies, including RAAS inhibition, endothelin receptor blockers, SGLT2 inhibitors, and immune-based therapies. Hypertension (HTN) and cardiovascular diseases are leading causes of mortality in glomerular diseases. The latter are intricately related with hypertension and share common pathophysiological mechanisms. Hypertension in glomerular disease represents a complex and multifaceted interplay between kidney dysfunction, immune-mediated, and non-immune-mediated pathology. Understanding the complex mechanisms involved in this relationship has evolved significantly over the years, shedding light on the pathophysiological processes underlying the development and progression of glomerular disease-associated HTN, and is crucial for developing effective therapeutic strategies and improving patients' outcomes.

Screening and evaluation of the hit compound from a DNA-encoded library derived from natural products based on immobilized endothelin receptor A

The enormous growing demand for drug candidates binding to endothelin receptor A (ETA) has made it necessary to continuously pursue new strategies for ligand screening and early evaluation. This work achieved the one-step immobilization of ETA based on the bioorthogonal chemistry between the epidermal growth factor receptor tag (EGFR-tag) and ibrutinib. Comprehensive characterizations including Western blot analysis are performed to realize the morphology, antibody/ligand recognition activity, and specificity of the immobilized ETA. Taking macitentan, ambrisentan, and bosentan as an example, we utilized the immobilized ETA to construct a thermodynamic model for the evaluation of the specific ligands binding to ETA. Using this model, we screened the potential compound NP845 from a DNA-encoded library with 10,686 members derived from natural products and calculated the association constant as (2.24 ± 0.15) × 105 M−1 at 37 °C, thereby demonstrating the good pharmacological activity of NP845. The entropy change (∆Sθ), enthalpy change (∆Hθ), and Gibbs free energy (∆Gθ) were 1.75 J/mol·K, −31.1 kJ/mol, and −31.6 kJ/mol at 37 °C, whereby we recognized the electrostatic force was the driving force of the interaction between NP845 and ETA. In vitro cell tests proved that NP845 can downregulate the expression level of PKA, B-Raf, MEK, and ERK1 in VSMC. Our results indicated that NP845 was a potential lead compound for fighting the ailments mediated by ETA.

Endothelin Receptor Blockade Improves Cerebral Blood Flow-Mediated Dilation in a Mouse Model of Alzheimer’s Disease

Introduction: Cerebral blood flow (CBF) is reduced in patients with Alzheimer’s disease (AD). Flow-mediated dilation (FMD), which plays a key role in the regulation of blood flow, is attenuated by endothelin-1. We hypothesized that endothelin receptor blockade may improve CBF in AD. Methods: We investigated cerebrovascular reactivity in a mouse model of AD (APP-PS1; 5-6-month-old male subjects). We assessed the in vivo response to normoxic hypercapnia and in vitro FMD in isolated cerebral and mesenteric resistance arteries before and after endothelin receptor blockade (bosentan). Results: Normoxic hypercapnia increased basilar trunk blood flow velocity (+12.3 ± 2.4%; p = 0.006, n = 6) in wild-type (WT) mice but reduced blood flow in APP-PS1 mice (−11.4 ± 1.2%; p < 0.0001, n = 8). Bosentan (50 mg/kg, acute intraperitoneal injection) restored cerebrovascular reactivity in APP-PS1 mice (+10.2 ± 2.2%; p < 0.0001, n = 8) but had no effect in WT. FMD was reduced in the posterior cerebral artery of APP-PS1 compared to WT and was normalized by bosentan (1 μmol/L, 30 min, or 50 mg/kg/day for 28 days). FMD was similar in the mesenteric artery of APPS-PS1 and WT. Conclusion: APP-PS1 mice exhibited cerebrovascular endothelial dysfunction. Acute and chronic blockade of endothelin receptors restored endothelial vasomotor function, suggesting a promising therapeutic approach to restoring cerebral vasoreactivity in AD.

Cardiomyocyte-specific deletion of endothelin receptor A (ETA) obliterates cardiac aging through regulation of mitophagy and ferroptosis

Advanced aging evokes unfavorable changes in the heart including cardiac remodeling and contractile dysfunction although the underlying mechanism remains elusive. This study was conducted to evaluate the role of endothelin-1 (ET-1) in the pathogenesis of cardiac aging and mechanism involved. Echocardiographic and cardiomyocyte mechanical properties were determined in young (5–6 mo) and aged (26–28 mo) wild-type (WT) and cardiomyocyte-specific ETA receptor knockout (ETAKO) mice. GSEA enrichment identified differentially expressed genes associated with mitochondrial respiration, mitochondrial protein processing and mitochondrial depolarization in cardiac aging. Aging elevated plasma levels of ET-1, Ang II and suppressed serum Fe2+, evoked cardiac remodeling (hypertrophy and interstitial fibrosis), contractile defects (fractional shortening, ejection fraction, cardiomyocyte peak shortening, maximal velocity of shortening/relengthening and prolonged relengthening) and intracellular Ca2+ mishandling (dampened intracellular Ca2+ release and prolonged decay), the effects with the exception of plasma AngII, ET-1 and Fe2+ were mitigated by ETAKO. Advanced age facilitated O2− production, carbonyl protein damage, cardiac hypertrophy (GATA4, ANP, NFATc3), ER stress, ferroptosis, compromised autophagy (LC3B, Beclin-1, Atg7, Atg5 and p62) and mitophagy (parkin and FUNDC1), and deranged intracellular Ca2+ proteins (SERCA2a and phospholamban), the effects of which were reversed by ETA ablation. ET-1 provoked ferroptosis in vitro, the response was nullified by the ETA receptor antagonist BQ123 and mitophagy inducer CsA. ETA but not ETB receptor antagonism reconciled cardiac aging, which was abrogated by inhibition of mitophagy and ferroptosis. These findings collectively denote promises of targeting ETA, mitophagy and ferroptosis in the management of aging-associated cardiac remodeling and contractile defect.

Patient and Therapeutic Profiles of Pulmonary Hypertension in Chronic Lung Diseases in Japan: A Cohort Study Using a Claims Database.

Pulmonary hypertension (PH) is often complicated by chronic lung diseases (CLDs) such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). Differentiating between PH associated with CLD (group3 PH) and pulmonary arterial hypertension (PAH) in CLD is often difficult and reporting on the efficacy of PAH-specific therapies is inconsistent as a result of the lack of understanding of the heterogeneity of patients with PH. A retrospective observational cohort study was conducted to understand the baseline characteristics, comorbidities, and treatment profiles of patients with PH in CLD in a real-world setting using a large-scale claims database (Medical Data Vision). Administrative and clinical data for patients admitted to acute-care hospitals in Japan between April 2008 and January 2021 were analyzed. A total of 115,921 patients with CLD (109,578 with COPD and 6343 with ILD, of whom 569 and 176 had PH, respectively) were analyzed. This study found lower PH diagnosis rates among patients with COPD and patients with ILD than in previous studies. The majority of PH with CLDpatients were elderly (mean age 75.7years) and male (80.81%). Among patients with CLD prescribed PAH-specific therapies (105 patients with COPD; 64 patients with ILD), most received these as monotherapy (COPD, 84.76%; ILD, 75.56%); the most common were phosphodiesterase5 inhibitors (COPD, 42.70%; ILD, 18.37%), prostacyclins (oral; COPD, 48.31%; ILD, 24.49%), and endothelin receptor antagonists (ERA) (COPD, 8.99%; ILD, 18.37%). Comorbidities (e.g., pulmonary, cardiac, kidney), home oxygen therapy (HOT), and echocardiography (ECHO) were factors associated with the diagnosis of PH. This is the first study using an administrative database that provides real-world data on patients with PH in CLD in Japan. Our results indicate that PH may be misdiagnosed or underdiagnosed in Japan which may lead to suboptimal treatment for patients, and supports the need for further evidence to guide appropriate treatment.

Reactive oxygen species mitigate perturbations in coronary microvascular tone in exercising swine with multiple risk factors

Abstract Background Multiple cardiovascular risk factors, such as diabetes mellitus (DM), chronic kidney disease (CKD) and dyslipidemia are known to induce inflammation and microvascular dysfunction contributing to impaired myocardial perfusion. We previously observed that a combination of DM, high fat diet (HFD) and CKD produced an increase in coronary microvascular tone in awake swine, resulting in perturbations in myocardial O2 balance. The increased microvascular tone was mediated by an impaired NO bioavailability and was accompanied by increased myocardial levels of reactive oxygen species (ROS) and increased circulating levels of endothelin (ET). Hypothesis: In the present study in swine, we tested the hypothesis that ROS scavenging and ET receptor blockade reduce coronary microvascular tone, improving myocardial O2 delivery and O2 balance in swine with DM+HFD+CKD. Methods DM (streptozotocin), HFD and CKD (renal artery embolization) were induced in 13 female swine (DM+HFD+CKD), while 11 healthy female swine on normal pig chow served as controls (Normal). After 6 months, the effects of ROS scavenging and ET receptor blockade on coronary microvascular tone were studied at rest and during graded treadmill exercise. Results 6 months of sustained hyperglycemia (18.1±1.0 in DM+HFD+CKD vs 8.5±0.6 mmol/l in Normal), hypercholesterolemia (12.3±2.0 vs 1.7±0.1 mmol/l) and renal dysfunction (plasma creatinine: 165±7 vs 119±3 µmol/l) were accompanied by systemic inflammation (TNF 52±5 vs 25±6 pg/ml), elevated ET plasma levels, (36±2 vs 29±2 pg/ml), and oxidative stress (myocardial PGF2a 12.9±0.8 vs 10.2±0.5 pg/mg protein, all P&amp;lt;0.05 by t-test). Surprisingly, in vivo ROS scavenging (TEMPOL+MPG) reduced myocardial O2 delivery (forcing an increased myocardial O2 extraction) in DM+HFD+CKD swine, indicative of a coronary microvascular constrictor response to ROS scavenging, implying a ROS-mediated vasodilator influence (Fig. A, B). In vitro experiments, using catalase in coronary small arteries, suggested a vasodilator role for hydrogen peroxide (H2O2) in DM+HFD+CKD but not in Normal swine. A switch from NO towards to H2O2 in the regulation of coronary microvascular tone was further supported by an increase in ceramide production (138±34 vs 45±4 nmol/ml, P&amp;lt;0.05) and increased activity of catalase in the myocardium (44±3 vs 31±4 nmol/min/mg, P&amp;lt;0.05) of DM+HFD+CKD vs Normal swine. Despite elevated ET plasma levels in DM+HFD+CKD swine, combined ETA/ETB receptor blockade with tezosentan did not affect myocardial O2 balance in either Normal or DM+HFD+CKD swine (Fig C, D). Conclusion In swine, 6 months exposure to multiple risk factors resulted in increased oxidative stress that paradoxically acted to mitigate perturbations in coronary microvascular tone via an H2O2-mediated coronary vasodilator influence. Despite an increase in circulating ET levels, we found no evidence for an increased ET-1 mediated coronary vasoconstrictor influence.

Triple therapy for incident pulmonary arterial hypertension in Finland between 2008 and 2020. A descriptive real-world FINPAH cohort study

Abstract Background Treatment of pulmonary arterial hypertension (PAH) with triple therapy (TriT) including phosphodiesterase type-5 inhibitors (PDE5), endothelin receptor antagonists (ERA), and prostacyclin receptor agonists (PRA) or analogues (PCA) is indicated in severe PAH. There is evidence of benefit also in intermediate-risk patients. Purpose To describe the real-world use of TriT in a contemporary cohort of Finnish PAH patients. Methods Data was collected via chart review by treating clinicians. Pulmonary hypertension (PH) patients were diagnosed between 2008–19 at the five Finnish university hospitals. Patient characteristics and clinical information were combined with mortality data from Statistics Finland. Persistence and survival were estimated using Kaplan-Meier. Results Out of 493 incident PH patients with medication history available, TriT was recorded for 41 (8%), with a median follow-up of 5.86 years (IQR: 4.12-8.72). TriT patients were predominantly women (73%), mean age 55 years (IQR 46–69) at diagnosis. 35 patients (85%) had PAH (37% iPAH, 27% PAH associated with connective tissue disease and 22% other PAH subclasses), and 6 patients (15%) had other PH types, mostly CTEPH. TriT was started at a median of 2.15 years (IQR: 0.65-3.64) after diagnosis. At the initiation of TriT, 7 patients (17%) had NYHA functional class (FC) IV, 21 (51%) had FC III, 8 (20%) had FC II. Median six-minute walking distance (6MWD) was 360 m (IQR 245-435 m, N=33). Median BNP was 328 pg/mL (IQR 190-723, N=10), and median NT-proBNP was 1082 pg/mL (IQR 745-3420, N=31). Fewer than 3 patients (&amp;lt;7%) were at ESC/ERS 2015 high risk. Initial PRA or PCA in TriT was iloprost (n=21, 51%), selexipag (n=12, 29%), or treprostinil (n=8, 20%). Initial ERA in TriT was macitentan (n=20, 49%), bosentan (n=11, 27%), or ambrisentan (n=10, 24%). Initial PDE5 was sildenafil (n=36, 88%) or tadalafil (n=5, 12%). Estimated persistence with TriT was 88% at 1 year and 84% at 5 years. Selexipag and iloprost were discontinued in &amp;lt;3 (&amp;lt;25% of users) and in 12 (57% of users), respectively, and 10 patients (24%) were switched to treprostinil. 6 TriT patients were listed for lung transplant after start of TriT, and 4 received a lung transplant. Six months after start of TriT, 4 patients (10%) had died and 5 (12%) had discontinued TriT. For the patients with 6 months of recorded TriT use (N=31), NT-proBNP changed by median -184 pg/mL (IQR -689 to +165, N=24), and 6MWD changed by median +20 m (IQR -3 to +35, N=22). In 8 patients (30%) FC improved within 6 months of TriT, was stable in 15 patients (56%) and worsened in 4 patients (15%). After 6 months of TriT, no patient was at high risk. Estimated overall survival was 90% (95%-CI 82-100%) at 6 months and 1 year after start of TriT. Estimated 5-year survival was 52% (95%-CI 38-72%). Conclusion(s) The study shows infrequent use but high persistence of TriT in Finnish PAH patients. TriT patients remained generally stable while on TriT.

Successful treatment of pulmonary hypertension and right heart failure by antibody-based functional blocking of the extra-domain A of fibronectin in a preclinical animal model

Abstract Background Pulmonary Hypertension (PH) as heterogeneous disease group is pathogenetically accompanied by pulmonary vascular and right ventricular tissue remodelling showing similarities between the clinical groups 1 (Pulmonary Arterial Hypertension), 2 (PH associated with left heart disease) and 3 (PH associated with lung disease). Since the remodelling process entails the abundant re-expression of extra-domain A containing fibronectin (ED-A+ Fn), which is virtually absent in healthy adult organs, a potential functional role in PH development and progression has been suggested and recently proven by our group. The human recombinant antibody F8 (IgG) specifically recognises ED-A+ Fn and is capable to block its function at least in vitro. Thus, F8 might serve as a novel therapeutic agent for the treatment or even prevention of PH. Purpose Against that background, the current study was aimed to test the therapeutic efficacy of F8 after systemic administration in a well-established preclinical model of PH in comparison to a non-specific control antibody and a dual endothelin receptor antagonist as standard of care. Methods Induction of PH was realized by subcutaneous injection of Monocrotaline (MCT) in mice. In total, 41 animals were included in the study approach and were divided into the following experimental groups: sham-treated controls (controls; n=7), PH mice without a specific treatment (PH_untreated; n=12), PH mice treated with the dual endothelin receptor antagonist Macitentan (PH_MAC; n=6), PH mice treated with the F8 antibody (PH_F8; n=8) and PH mice treated with an antibody of irrelevant antigen specificity in the murine system (PH_KSF; n=8). Treatment effects were evaluated on the haemodynamic, echocardiographic and microscopic level. Results In comparison to controls, untreated PH mice showed significantly higher right ventricular systolic pressure values (RVPsys, p&amp;lt;0.05) as well as impaired echocardiographic parameters of right ventricular morphology and function, i.e., enlarged basal right ventricular (RVbasal, p=0.016) diameters and reduced tricuspid annular plane systolic excursion values (TAPSE, p=0.008). In the PH_F8 group, haemodynamic and echocardiographic parameters were significantly improved compared to the PH_untreated or the PH_KSF group (p&amp;lt;0.05 for the majority of parameters). Histological evaluation revealed significant lung tissue damage after in the PH_untreated group compared to controls (p=0.008), which were significantly attenuated in the PH_F8 (p=0.04) but not the PH_KSF group (p=n.s.). Conclusion The therapeutic efficacy of the human recombinant F8 antibody specific to ED-A+ Fn has been proven for the first time in vivo in a well-established preclinical model of PH. F8 acts as a disease-modifier by attenuating PH associated lung tissue remodelling resulting in remarkable improvements of pulmonary hemodynamics and echocardiographic parameters of right ventricular load.

Adults with congenital heart disease and pulmonary arterial hypertension: Quantitative assessment of haemodynamic parameters under disease targeting therapy - A retrospective multicentre analysis

Abstract Background Pulmonary arterial hypertension (PAH) occurs in approximately 10% of adults with congenital heart disease (ACHD), usually develops secondary to intra- or extra-cardiac shunts resulting in pressure and/or volume overload in the pulmonary circulation, and is associated with increased morbidity and mortality. Treatment strategies for PAH-ACHD include disease targeting therapies (DTT), such as phosphodiesterase-5 inhibitors (PDE5i) and endothelin receptor antagonists (ERA). Data regarding the impact of DTT on cardiopulmonary haemodynamics in PAH-ACHD are scarce. Purpose Aim of this study was to quantify effects of DTT on cardiopulmonary haemodynamics (assessed by right heart catheterisation [RHC]) and on key non-invasive functional parameters contributing to ESC/ERS risk status in PAH-ACHD patients, as applied in real-world clinical practice. Methods We retrospectively analysed the effect of DTT in PAH-ACHD patients who had undergone RHC in adulthood at baseline (treatment-naïve) between 2000 and 2022, with at least one follow-up RHC during DTT, in six expert centres in Europe. Clinical characteristics (WHO functional class [WHO-FC], 6-minute walking distance [6MWD], N-terminal pro-brain natriuretic peptide [NTproBNP] and measures of RHC (systemic/ pulmonary cardiac output, systolic/diastolic/mean pulmonary arterial pressure [sPAP, dPAP, mPAP], and pulmonary arterial wedge pressure [PAWP]) were collected. Pulmonary vascular resistance/arterial compliance (PVR+PAC) and stroke volume index (SVI) were calculated. Results 44 patients (70% female, mean age 45±15 years) were included. Underlying CHD was a pre- or post-tricuspid shunt in 35% and 63%, respectively. 14% had complex CHD, 7% had innate left heart disease, and 21% presented with Eisenmenger´s syndrome. At baseline 71% were in WHO-FC III/IV, 6MWD was 371±105 m, and NTproBNP was 673 [446–1021] ng/l. On RHC, mPAP was 58±15 mmHg, PVR 11 [7–17] wood units (WU), SVI 32 [27–44] ml/min/m2, CI 2.7±1.0 l/min/m2, and PAC 1.0 [0.7–1.4] ml/mmHg. DTT was started in all patients after baseline RHC. 81% received monotherapy (34% PDE5i, 66% ERA) and 19% received upfront combination therapy (PDE5i+ERA). Follow-up RHC was performed 15 [5–33] months after baseline RHC. At follow-up, WHO-FC and NTproBNP (562 [428-762] ng/l) significantly improved (p&amp;lt;0.001 and p=0.021, respectively), as did hemodynamic measures: mPAP (53±15 mmHg, p&amp;lt;0.001), PVR (9 [5–10] WU, p&amp;lt;0.001), SVI (37 [30–49] ml/min/m2, p=0.010), PAC (1.3 [1.0–1.7] ml/mmHg, p&amp;lt;0.001), and CI (3.1±1.1 l/min/m2, p=0.001). In contrast, 6MWD showed subtle change (379±111 m, p=0.164). After follow-up RHC, DTT was escalated in 78% of patients. Conclusions In PAH-ACHD patients, DTT was associated with a moderate but sustained haemodynamic and functional improvement after 15 months. Repeat RHC triggered treatment escalation in most patients. Therefore, ongoing vigilance for PAH-ACHD patients and subsequent treatment optimisation is warranted.

Hemodynamic changes with pulmonary arterial hypertension targeted therapies: a meta-analysis of 3898 treatment-naive patients

Abstract Background Pulmonary arterial hypertension (PAH)-targeted therapies exert significant hemodynamic changes. We aimed to systematically synthesize these effects and explore the pulmonary pressure and flow changes in relation to the resistance changes. Methods We systematically searched PubMed, CENTRAL, and Web of Science for studies evaluating the hemodynamic effects (mean pulmonary artery pressure [mPAP], cardiac index/output [CI/CO], pulmonary vascular resistance [PVR]) of PAH-targeted therapies (comprising endothelin receptor antagonists [ERA], phosphodiesterase type 5 inhibitors [PDE5i], prostanoids [either i.v./s.c. or p.o./inh], riociguat, and selexipag) either in monotherapy or combinations as assessed by right heart catheterization (RHC) in treatment-naïve PAH patients. We performed a random-effects meta-analysis and used meta-regression to evaluate the contribution of mPAP % reduction and CI/CO % increase on the PVR % reduction across different treatment groups. Results We included 68 studies comprising 90 treatment groups and 4276 patients (age 47.3±13.2, 74% women). PVR reduction as a percentage of the pre-treatment value was more pronounced in the oral + prostanoid i.v./s.c. combination therapy (mean difference [MD] -50.0%, 95% confidence interval [CI] -60.8%; -39.2%), compared to oral combination therapy (MD -41.7%, 95% CI -47.6%; -35.8%), prostanoid i.v./s.c. monotherapy (MD -31.8%, 95% CI -37.6%; -25.9%), and oral monotherapy (MD -21.6%, 95% CI -25.4%; -17.8%) (Figure 1). The contribution of mPAP % reduction and of CI/CO % increase to the PVR % reduction was equally significant in all treatment groups (Figure 2). In the oral combination therapy group CI/CO % increase had superior contribution over mPAP % reduction (R2 90% vs R2 0%), but this difference was driven by an outlier study with n = 8 patients and after the exclusion of the outlier, the contribution of mPAP % reduction and of CI/CO % increase to the PVR % reduction was equally significant also in the oral combination group. The same results applied in a sensitivity analysis including only studies with idiopathic/heritable/drugs-induced/connective tissue disease-associated PAH patients. Conclusion Combination therapies, especially with the inclusion of parenteral prostanoids, lead to remarkable hemodynamic improvement in treatment-naïve PAH patients. The contribution of mPAP and CI/CO % changes to the overall PVR % reduction is equally significant.Figure 1Figure 2

Macitentan tadalafil Fixed Dose Combination (FDC) in treatment-naive and prior monotherapy patients with Pulmonary Arterial Hypertension (PAH): insights from A DUE

Abstract Background Combination therapy is recommended for the management of pulmonary arterial hypertension (PAH). The A DUE study showed that M/T FDC, a fixed dose combination (FDC) of the endothelin receptor antagonist (ERA) macitentan 10mg (M) and the phosphodiesterase type 5 inhibitor (PDE5i) tadalafil 40mg (T), led to a clinically relevant improvement in pulmonary vascular resistance (PVR) vs macitentan and tadalafil monotherapies in PAH patients. A clinically meaningful trend for improvement in 6-minute walk distance (6MWD) in favor of M/T FDC vs macitentan and tadalafil was observed. Purpose Here we analysed the effect of M/T FDC in the subgroups of treatment-naïve and prior monotherapy patients. Methods In A DUE 187 adult PAH patients in WHO functional class II / III were randomised 2:1:1 to M/T FDC, macitentan or tadalafil if treatment-naïve, 2:1 to M/T FDC or macitentan if on prior ERA, and 2:1 to M/T FDC or tadalafil if on prior PDE5i. The treatment effect of M/T FDC vs macitentan and M/T FDC vs tadalafil was calculated using ANCOVA models for PVR (geometric mean ratios [95% CL]) and for 6MWD (mean change [95% CL]) in treatment-naïve patients and in patients on prior monotherapy (ERA or PDE5i) at randomisation. Results Treatment effects for M/T FDC versus macitentan and versus tadalafil on the change in PVR and 6MWD are reported in the table for each subgroup, along with those for the overall population. The safety profile of M/T FDC was in line with the safety profiles of macitentan and tadalafil. Conclusions In A DUE, the effect of M/T FDC vs both monotherapies on PVR and 6MWD in treatment-naïve and prior ERA/PDE5i patients was consistent with that observed in the overall population.

Efficacy comparison of prostacyclin analogue and prostacyclin receptor agonist as third line treatment for pulmonary arterial hypertension

Abstract Background Pulmonary arterial hypertension (PAH) is a progressive disease characterized by small pulmonary arteries remodeling that leads to increased pulmonary vascular resistance, dyspnea, fatigue, right heart failure and ultimately death. Prostacyclin analogue drugs, such as epoprostenol or treprostinil, have a vasodilator, antiproliferative and immunomodulatory effect, representing established therapies for cases of severe PAH. Both these drugs improve exercise capacity, functional class and hemodynamic parameters, while epoprostenol also improves survival among patients with PAH. Despite these therapeutic benefits, these treatments need parenteral administration. Recently, the approval of selexipag, an oral selective prostacyclin receptor agonist, may represent a possible alternative option in some PAH patients. Methods Patients with PAH treated as third line therapy with epoprostenol, treprostinil or selexipag, on top of inhibitor of type 5 phosphodiesterases and endothelin-1 receptor antagonists, referred to our center from February 1995 to December 2021 were retrospectively included. All patients noninvasive [6 minutes walking distance (6MWD)] and invasive [mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index (CI), right atrial pressure (RAP) and mixed venous oxygen saturation (SvO2)] parameters were first collected at the baseline right heart catheterization (prior to the beginning of prostacyclin treatment) and then 3-4 months after the beginning of third line therapy. The absolute improvements in these parameters were compared with Dunn’s test. Data are expressed as median (interquartile range). Results 153 PAH patients treated as third line therapy with epoprostenol, treprostenil and selexipag were included (44, 73, 36 patients respectively). At 3 to 4 months after the beginning of the third line therapy, absolute improvements in the different parameters are shown in Figure 1. Conclusions In our study population, epoprostenol, treprostenil and selexipag improve both exercise capacity and haemodynamic parameters in PAH patients when used as third line therapy, with the highest efficacy in the first group and, possibly, the lowest efficacy in the latter. These results confirm the beneficial role of these drugs in PAH patients and may suggest a possible favorable role for selexipag in the management of PAH patients with a less severe disease reserving a more invasive treatment strategy with parenteral prostanoids in patients with a higher risk disease.Figure 1

Reduced trans-myocardial extraction of endothelin-1 in cardiac allograft vasculopathy

Abstract Introduction Cardiac allograft vasculopathy (CAV) is a major cause of graft failure due to microvascular dysfunction and ischaemia following heart transplant. Endothelin-1 (ET-1) is an endothelium derived vasoconstrictor peptide with multiple adverse effects including vascular smooth muscle proliferation and pro-inflammatory signalling. Elevated circulating ET-1 has been associated with accelerated CAV. We assessed the trans-myocardial gradient (TMG: coronary sinus minus coronary artery concentration: negative=extraction, positive=secretion) of ET-1 in heart transplant patients to determine correlations with angiographic, Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) features of CAV. Methods 23 patients underwent invasive coronary angiography, 3-vessel grey scale IVUS (Opticross, 60mHz, Boston Scientific) and OCT (Dragonfly, Abbott Vascular) to define morphological features of vasculopathy 18±3 months post-transplant. Paired blood samples were obtained from the guide catheter and coronary sinus at the time of coronary imaging. Plasma was analysed using specific enzyme-linked immunosorbent assay for ET-1 peptide quantification. Survival was determined 98±5 months after initial assessment. Results ET-1 TMG distribution was mostly in the negative range reflecting net extraction across the coronary vascular bed (median [IQR]: -0.23 [-0.54, -0.02] pg/ml). However, vessels with more severe CAV demonstrated significantly more positive TMG i.e. less ET-1 trans-myocardial extraction (IVUS Stanford Grade IV: -0.05 [-0.21, 0.13] pg/ml versus Stanford Grade I-III: -0.31 [-0.64, -0.11] pg/ml, p = 0.01). ET-1 TMG was positively correlated with mean intimal thickness on both IVUS and OCT (IVUS: Kendall’s tau-b = 0.254, p=0.02 and OCT: Kendall’s tau-b = 0.344, p&amp;lt;0.0001). Patients who died had net ET-1 secretion compared with surviving patients (died: 0.21 [0.19 - 0.24] versus surviving: -0.28 [-0.52, -0.17], p = 0.01). Conclusions In heart transplant patients, coronary arteries with more intimal thickening had less trans-myocardial extraction, and more secretion of ET-1. ET-1 secretion in CAV may mediate the distal microvascular dysfunction commonly seen in this condition. These findings suggest a rationale for testing ET-1 receptor antagonists as a treatment for CAV.ET-1 TMG and IVUS Stanford Grade of CAVET-1 TMG and OCT derived MIT

Abstract 16323: Functional Autoantibody Analysis in Post-Acute Sequela of COVID-19 Patients With and Without Pots: A Case Control Study

Introduction: Post-Acute Sequela of COVID-19 (PASC) occurs after recovery from the initial illness. Autonomic dysfunction (AD) may explain these findings. We have previously shown orthostatic intolerance (OI) on standard Italian protocol head-up tilt table in 23 of 24 prospectively studied subjects with PASC and no prior OI. Postural orthostatic tachycardia syndrome (POTS) was noted in 4 of the 23. POTS is associated with elevated levels of autoantibodies. There is a paucity of data evaluating autoantibody presence in subjects with PASC related POTS. Hypothesis: We hypothesized that individuals with PASC related POTS would demonstrate higher levels of certain autoantibodies than controls. Methods: We recruited healthy, COVID-19 PCR negative controls, all previously vaccinated for COVID, who were age and gender matched with the 4 previously identified PASC related POTS patients. Serum was tested for autoantibodies in both groups. Results: Mean ages for the PASC related POTS and control groups were 29 and 31 years, respectively. The PASC related POTS patients had higher levels of functional autoantibodies to several G-protein coupled receptors than controls. The median values for adrenergic A1, adrenergic B2, muscarinic M4, angiotensin 2 and endothelin receptors, comparing controls to PASC related POTS patients, were 10.4 vs 27.5, 14.9 vs 38.5, 7.8 vs 29.0, 12.2 vs 29.5 and 12.6 vs 31.7 Units/ml, respectively. The small size of the 2 groups precludes meaningful statistical testing, but the box plots in Figure 1 show consistent differences in the concentration of antibody receptors seen between the 2 groups. Conclusions: Functional autoantibodies to several G-protein coupled receptors were seen in higher amount in subjects with PASC related POTS compared to healthy controls. While this is a small, case-control study, it suggests a potential autoantibody mediated mechanism that may explain some of the AD seen in PASC patients with POTS.

Therapeutic properties, biological effects, antiliver cancer, and anticolon cancer effects of some natural compounds: A biochemical approach.

Natural compounds, such as carotenoids, flavonoids, anthocyanins, or terpenoids, are physiologically active components found in plants (pigments), often known as phytochemicals or phytonutrients. The in vitro cytotoxic and anticolon cancer effects of biologically bavachin, bavachinin, artepillin C, and aromadendrin compounds against SW48, SNU-C1, COLO 205, RKO, LS411N, and SW1417 cancer cell lines were assessed. Results of enzymes and antibacterial, antifungal were in level of micromolar that is good impacts. These natural compounds may be antidiabetic, anticancer, and antibacterial candidates for drug design. IC50 results were obtained between 14-19 and 5-119 µM for α-amylase and α-glucosidase, respectively. Good inhibitor Bavachinin was detected for both enzymes (IC50 for α-amylase: 14.37 µM and IC50 for α-glucosidase: 5.27 µM). The chemical activities of aromadendrin, artepillin C, bavachin, and bavachinin against pancreatic α-amylase and α-glucosidase were assessed by conducting the molecular docking study. The chemical activities of aromadendrin, artepillin C, bavachin, and bavachinin against some of the expressed surface receptor proteins (CD44, CD47, CXCR4, EGFR, folate receptor, HER2, and endothelin receptor) in the mentioned cell lines were investigated using the molecular docking calculations. The results illustrated the atomic-level properties and potential interactions. These chemicals have high binding affinities to the enzymes and proteins, according to the docking scores. In addition, the compounds formed strong contacts with the enzymes and receptors. Thus, these compounds could be potential inhibitors for enzymes and cancer cells.

Abstract 11964: The Effect of Endothelin-1 on Angiotensin II-Induced Renal Injury

Introduction: Hypertension (HT) and kidney disease is increasingly recognized as a global public health problem. Angiotensin II (AngII) induces endothelin-1 (ET-1), and ET-1 is a key mediator of kidney fibrosis. Hypothesis: Inhibition of ET-1 may contribute to modulation of HT and renal injury induced by angiotensin II. Methods: In addition to wild-type (WT) mice, we also used IL-1 receptor antagonist-deficient (IL-1Ra -/- ) mice that were prone to AngII-induced renal inflammation, because WT (C57BL) mice were genetically resistant to renal injury in response to AngII. Both mice were infused with AngII (1000ng/kg/min) using subcutaneous osmotic pumps for 14 days. Results: Systolic blood pressure in IL-1Ra -/- mice significantly increased compared with WT mice (197±5 vs 169±9 mmHg, p&lt;0.05). Furthermore, renal preproendothelin-1 mRNA expression and serum levels of ET-1 were also significantly higher in IL-1Ra -/- mice (p&lt;0.05). Immunostaining revealed that ET-1 was elevated in glomeruli and tubules in the cortex of IL-1Ra -/- mice compared with WT mice (Figure upper panels: ET-1 staining), indicating elevated ET-1 might contribute to glomerular injury (Figure middle panels: PAS staining) and intratubule fibrosis (Figure lower panels: Elastica Masson staining) detected in the histological analysis. Finally, we investigated whether pharmacological inhibition of ET receptors could prevent AngII-induced renal injury in IL-1Ra -/- mice. Bosentan significantly decreased AngII-induced HT, and protected renal injury in IL-1Ra -/- mice. On the other hand, treatment of hydralazine, an antihypertensive agent, did not suppress renal damage in AngII-infused IL-1Ra -/- mice in spite of improvement of HT. Conclusions: Our results indicate that inhibition of ET-1 might protect AngII-induced renal inflammation beyond an antihypertensive therapy, suggesting that we might be required to develop new strategies for blocking ET-1 to prevent hypertensive renal injury.

Abstract 12535: Spontaneous Coronary Artery Dissection in Women: A New Role for Autoimmunity?

Introduction: Spontaneous coronary artery dissection (SCAD) is an uncommon cause of myocardial infarction (MI) in women, with a still unclear pathophysiology. Autoantibodies targeting angiotensin-II receptor type 1 (AT1R) and endothelin-1 receptor type A (ETAR) (AT1R-AAs and ETAR-AAs, respectively) lead to endothelial dysfunction and have already been associated with aortic dissection. Hypothesis: We hypothesized that titers of AT1R-AAs and ETAR-AAs are higher in patients with SCAD compared to controls. Methods: Our case-control study was conducted at Padua University Hospital between January 2022 and June 2022. Female patients diagnosed at coronary angiography with MI and SCAD were consecutively enrolled. Ten women with SCAD and 20 age-matched controls (10 women with ST-elevation MI (STEMI) and 10 healthy women) were included. Serum levels for AT1R-AAs and ETAR-AAs were determined for each participant. Absolute autoantibody titers and seropositivity prevalence were compared between SCAD patients, STEMI patients, and healthy women. Seropositivity was defined according to the threshold value suggested by the manufacturer (&gt;10 U/mL). Results: Six out of 10 (60%) women with MI and SCAD were seropositive for AT1R-AAs and ETAR-AAs. In contrast, only one (10%) healthy woman and one (10%) STEMI patient were seropositive for AT1R-AAs (p=0.03 and p=0.03, respectively). One STEMI patient was seropositive for ETAR-AAs, while none of the healthy women was found to be seropositive (p=0.03 and p=0.01, respectively). The median autoantibody titer was significantly higher in SCAD patients than in healthy women (p=0.01 for AT1R-AAs; p=0.02 for ETAR-AAs) and STEMI patients (p&lt;0.001 for AT1R-AAs; p=0.002 for ETAR-AAs). Conclusions: AT1R-AAs and ETAR-AAs seropositivity is significantly higher in SCAD women than in healthy women or female patients with STEMI. Our findings suggest a possible role for AT1R-AAs and ETAR-AAs in the pathophysiology of SCAD in women with MI.

Abstract 12646: Autoantibodies Targeting Endothelin Type-A Receptors Associate With no Reflow After ST-elevation Myocardial Infarction

Introduction: No-reflow (NR), where the coronary artery is patent after treatment of ST-elevation myocardial infarction (STEMI) but tissue perfusion is not restored, is associated with worse outcome. Although several mechanisms contributing to NR have been identified, its pathophysiology is still not completely understood. Autoantibodies activating endothelin-1 receptors type A (ETAR-AAs) exert their detrimental effects through vasoconstriction, fibrosis, and inflammation. Interestingly, all these factors are also involved in NR. Hypothesis: We hypothesized that, after reopening of the epicardial coronary artery, the preexistence of ETAR-AAs might have detrimental effects on coronary microcirculation, resulting in microvascular obstruction (MVO) and, thus, NR. Methods: Our prospective study was conducted at Padua University Hospital between January 2022 and December 2022. Consecutive patients with STEMI who underwent PPCI within 6 h after the onset of symptoms were enrolled. Blood samples were obtained from all patients within 12 hours after the admission for ETAR-AAs level measurement. MVO was assessed by cardiac magnetic resonance imaging, within 15 days after successful PPCI. The seropositive threshold was provided by the manufacturer (&gt;10 U/ml). Results: We recruited 50 patients with STEMI. MVO was observed in 24 patients (48%). ETAR-AAs were higher in patients with MVO (8.9 U/mL (interquartile range [IQR] 6.8-16.2 U/mL) vs. 5.7 U/mL [IQR 4.3-7.7 U/mL], p=0.002). The prevalence of MVO was higher in patients with ETAR-AAs seropositivity (72% vs. 38%, p=0.03). ETAR-AAs seropositivity was independently associated with MVO (OR 3.2, 95% CI 1.3-7.1; p=0.03). Conclusions: ETAR-AAs concentration are associated with MVO in STEMI patients. These findings set the stage for a better pathophysiological understanding of NR and may open new options in the management of myocardial infarction.

Abstract 12559: Functional Autoantibodies Against Angiotensin II Receptor Type 1 and Endothelin-1 Receptor Type A Predict Adverse Remodeling and Cardiovascular Events After Acute Myocardial Infarction

Introduction: Myocardial infarction is a leading cause of death worldwide. Although advances have been made in acute treatment, an incomplete understanding of left ventricular (LV) remodeling (LVR) processes has limited the effectiveness of therapies to reduce late-stage mortality. Hypothesis: We hypothesized that autoantibodies (AAs) activating angiotensin II receptor type 1 (AT1R-AAs) and endothelin-1 receptor type A (ETAR-AAs) are associated with LVR after ST-elevation myocardial infarction (STEMI) and with recurrent major adverse cardiac events (MACE). Methods: We studied 131 STEMI patients (age 61±11 years, 112 males) treated with primary percutaneous coronary intervention between February 2021 and January 2022 at Padua University Medical Center. Within 48 hours of admission standard 2D echocardiography was performed and blood samples were obtained for AAs level measurement. Echocardiography was performed at 6 months repeatedly in all patients. The endpoint was LVR, defined as an increase of 20% or more of LV end-diastolic volume index. Results: Overall, 41 (32%) patients experienced LVR. The titer for the autoantibodies was significantly higher in patients with LVR (p=0.009 for AT1R-AAs; p=0.01 for ETAR-AAs). The prevalence of AT1R-AAs and ETAR-AAs seropositivity was higher in patients with LVR (39% vs. 11%, p&lt;0.001 and 37% vs. 12%, p=0.001, respectively). At multivariable analysis, AT1R-AAs seropositivity was the strongest predictor of LVR (OR=4.25, p=0.002). Similarly, AT1R-AAs seropositivity was a strong predictor of recurrent MACE, both before (OR, 4.09; p = 0.006) and after (OR 19.6; p=0.002) adjusting for the confounding factors. Conclusions: Our results support the hypothesis that AT1R-AAs and ETAR-AAs concentration are a risk factor for LVR in STEMI patients. AT1R-AAs is also a predictor of recurrent MACE. These initial observations may set the stage for a better pathophysiological understanding of the mechanisms contributing to LVR.