Endothelin Receptor Research Articles

C-C motif chemokine receptor-2 blockade ameliorates pulmonary hypertension in rats and synergizes with a pulmonary vasodilator

Abstract Aims We investigated whether the disruption of C-C motif chemokine receptor (CCR) 2 may attenuate the development of pulmonary arterial hypertension (PAH) in any rat models with the reversal of the associated pro-inflammatory state and vascular dysfunction, and synergize with a conventional pulmonary vasodilator. Methods and Results Using Ccr2(-/-) rats generated by CRISPR/Cas9, we investigated pulmonary hypertension (PH) in Ccr2(+/+) or Ccr2(-/-) rats treated with monocrotaline (MCT), SU5416/hypoxia (SuHx) and chronic hypoxia (CH). Ccr2(-/-) decreased the right ventricular systolic pressure, an index of right ventricular hypertrophy and mortality rate, and reversed increased expression of inflammatory cytokines/chemokines (interleukin-6, tumor necrosis factor-α, C-C motif chemokine receptor (CCL)-2, interleukin-1β, transforming growth factor-β) in rats 3weeks after MCT injection, but not in SuHx or CH models. Consistently, Ccr2(-/-) decreased indices of pulmonary vascular diseases (PVD) and perivascular macrophage infiltration, as well as reversed impaired bone morphogenetic protein receptor type 2 signaling, increased endothelial apoptosis and impaired nitric oxide signaling and decreased phosphodiesterase-5 (PDE5) expression in lungs in MCT-treated rats. Gene expression of receptors for prostaglandin I2 and endothelin was not changed by Ccr2(-/-) in MCT-treated rats. In cultured pulmonary arterial smooth muscle cells (PASMCs), Ccr2(-/-) suppressed CCL2-induced hyperproliferation and dedifferentiation as well as reversed CCL2-induced decrease in PDE5 expression. The whole-genome RNA sequencing analysis identified differentially expressed genes in CCL2-stimulated Ccr2(-/-) PASMCs, which are related to regulation of cellular differentiation and contraction. Based on studies in rats and cultured PASMCs, we investigated whether a PDE5 inhibitor, tadalafil, synergizes with Ccr2(-/-). Tadalafil administration ameliorated PH and PVDs in MCT-treated Ccr2(-/-) rats but not in Ccr2(+/+) rats. Tadalafil further improved survival in MCT-treated Ccr2(-/-) rats. Conclusion The present findings demonstrated that CCR2 disruption ameliorated PAH in MCT-treated rats, which was associated with the reversal of dysregulated inflammatory pathways and vascular dysfunction and synergized with tadalafil. These findings suggest that CCR2 may be a therapeutic target in intractable PAH patients with a certain CCR2-related inflammatory phenotype and refractory to conventional pulmonary vasodilators.

Exploring the Endothelin-1 pathway in chronic thromboembolic pulmonary hypertension microvasculopathy.

Targeted vasopeptide therapies have significantly advanced the management of pulmonary arterial hypertension (PAH). However, due to insufficient preclinical evidence regarding the involvement of the endothelin-1 (ET-1) pathway in chronic thromboembolic pulmonary hypertension (CTEPH) pathophysiology, the potential of ET-1 receptor antagonism in treating CTEPH remains uncertain. In this study, we investigated the role of the ET-1 pathway in CTEPH microvasculopathy using a multifaceted approach. Plasma ET-1 levels were measured in a cohort of 59 CTEPH patients and 41 healthy controls. Additionally, we evaluated the expression of key ET-1 pathway members in pulmonary explants from CTEPH, idiopathic PAH, and control patients. We used an in vitro system to test the hypothesis that the turbulent flow, observed near the vascular obstructions pathognomonic of CTEPH, enhances ET-1 expression. Our findings were further validated in vivo using a CTEPH piglet model that contains distinct regions representing pre- and post-thrombus lung territories. We found a twofold increase in circulating ET-1 levels in CTEPH patients compared to healthy subjects. Pulmonary explants from CTEPH patients exhibited pronounced overexpression of ET-1, endothelin receptor A (ETA), and phosphorylated myosin light chain (p-MLC) in muscularized pulmonary microvessels, suggesting heightened vascular contraction. In vitro experiments showed that turbulent flow facilitates ET-1 secretion compared to laminar flow regions. Additionally, in the CTEPH piglet model, elevated plasma ET-1 levels were observed compared to controls. Immunofluorescence and confocal microscopy analyses confirmed increased ETA and p-MLC in remodeled arteries from both pulmonary territories. However, ET-1 protein elevation was exclusively observed in the obstructed territory. These findings collectively indicate impaired vascular tone in microvessels of CTEPH patients and the CTEPH piglet model. Furthermore, our data implicates the ET-1 pathway in microvasculopathy, with turbulent flow playing a pathological role. These insights underscore the potential utility of ET-1 receptor antagonists as a promising therapeutic approach for CTEPH treatment.

Endothelin-1 receptor blockade impairs invasion patterns in engineered 3D high-grade serous ovarian cancer tumouroids.

High-grade serous ovarian cancer (HG-SOC), accounting for 70-80% of ovarian cancer deaths, is characterized by a widespread and rapid metastatic nature, influenced by diverse cell types, cell-cell interactions, and acellular components of the tumour microenvironment (TME). Within this tumour type, autocrine and paracrine activation of the endothelin-1 receptors (ET-1R), expressed in tumour cells and stromal elements, drives metastatic progression. The lack of three-dimensional models that faithfully recapitulate the unique HG-SOC TME has been the bottleneck in performing drug screening for personalized medicine. Herein, we developed HG-SOC tumouroids by engineering a dense central artificial cancer mass (ACM) containing HG-SOC cells, nested within a compressed hydrogel recapitulating the stromal compartment comprising type I collagen, laminin, fibronectin, and stromal cells (fibroblasts and endothelial cells). ET-1-stimulated HG-SOC cells in the tumouroids showed an altered migration pattern and formed cellular aggregates, mimicking micrometastases that invaded the stroma. Compared with control cells, ET-1-stimulated tumouroids showed a higher number of invasive bodies, which were reduced by treatment with the dual ET-1 receptor (ET-1R) antagonist macitentan. In addition, ET-1 increased the size of the invading aggregates compared with control cells. This study establishes an experimental 3D multicellular model eligible for mechanical research, investigating the impact of matrix stiffness and TME interactions, which will aid drug screening to guide therapeutic decisions in HG-SOC patients.

Abstract 4134327: Efficacy and safety of aprocitentan in patients with resistant hypertension receiving at least 4 antihypertensive medications including beta (β) blockers

Background: Aprocitentan, a dual ET A /ET B endothelin receptor antagonist, was recently FDA-approved for use in combination with other drugs for the treatment of hypertension not adequately controlled on other antihypertensive drugs. β-blockers are used for the prevention of cardiovascular events and have antihypertensive effects. All subjects in the PRECISION study were hypertensive at screening despite receiving ≥3 antihypertensives, with 63.5% on ≥4 and 16.8% on ≥5 antihypertensives. All were switched to a standardized fixed dose triple combination of amlodipine/valsartan/hydrochlorothiazide; and the 456 patients (62.5% of the 730 total) who were on β-blockers at screening continued throughout the study as well. Of these, 173 (37.9%) had a history of ischemic heart disease and 106 (23.2%) a history of congestive heart failure, vs 52 (19%) and 37 (13.5%) not receiving β-blockers. This preplanned subgroup analysis assessed the efficacy and safety of aprocitentan in patients with resistant hypertension on the triple combination with or without β-blockers. Methods: Changes from baseline (BL) in office systolic blood pressure (SBP) and diastolic BP (DBP) were assessed at Week 4, the end of the double-blind treatment phase with aprocitentan 12.5 mg or 25 mg per day or placebo, and at Week 36, at the end of the single-blind aprocitentan 25 mg treatment phase. Results: There was no difference in the efficacy of aprocitentan when patients were on a β-blocker or not. In patients on β-blockers, 12.5 mg and 25 mg aprocitentan decreased SBP from BL to Week 4 by mean -14.9 mmHg and -14.9 mmHg, respectively, vs -11.2 mmHg in the placebo group; and in patients without β-blockers by -16.5 mmHg and -14.9 mmHg vs -11.8 mmHg. Similar results were seen at Week 36, as compared with BL for both subgroups, and at Week 4 for DBP (Table 1). In patients on β-blockers, the incidence of edema/fluid retention at Week 4 was 9.9%, 19.3% and 2.8% in the aprocitentan 12.5 mg, 25 mg and placebo groups, respectively, as compared with 7.6%, 16.7%, and 1.0% in patients without β-blockers. In both subgroups, most events occurred during the first 8 weeks of treatment. The incidence of edema/fluid retention with aprocitentan was comparable with that of the placebo group in both subgroups thereafter. Conclusions: Aprocitentan is effective in lowering BP and has a good safety and tolerability profile in patients with resistant hypertension who are taking 4 or more antihypertensive drugs including β-blockers.

Abstract 4119891: Risk Factors of Anemia in Pulmonary Arterial Hypertension Patients with Endothelin Receptor Antagonists Administration and Related Treatment

Background: Endothelin receptor antagonists (ERAs) demonstrated significant efficiency in delaying clinical deterioration and improving survival of patients with pulmonary arterial hypertension (PAH). However, the frequent occurrence of anemia after ERAs administration has gained clinical attention currently, whereas the etiology of anemia is unclear. The risk factors of ERAs associated anemia remained undefined. Therefore, we aim to investigate risk factors of developing anemia after ERAs treatment and whether iron supplement could correct anemia. Method: A retrospective cohort study was performed among patients with PAH who received ERAs between January, 2017 and December, 2019 in Fuwai hospital. The primary outcome was development of anemia after ERAs therapy and secondary outcome was correction of anemia after iron supplement. Results: A total of 120 patients with PAH were included in the study and 28 patients developed anemia during follow up . Distinctively, all the patients who developed anemia were female. After ERAs administration, iron metabolism (Ferritin 95.29±144.79 μg/L versus 69.9±118.25 μg/L, P <0.001) and hemoglobin (154.21±23.80 g/L versus 136.12±28.61 g/L, P <0.001) reduced significantly in the total cohort with patients who developed anemia more significant. Baseline iron metabolism (Ferritin: HR 0.98, 95%CI 0.96-0.99, P =0.02) was independently associated with development of anemia after ERAs administration. Compared with patients with iron replete, patients with iron deficiency had over 9-fold risk of developing anemia after receiving ERAs (HR = 9.59, 95%CI 3.62-25.41, P < 0.01). Iron supplement could effectively correct anemia. Conclusion: It is advised that patients receiving ERAs monitor iron metabolism and hemoglobin regularly, especially females and those with low hemoglobin level and compromised iron homeostasis before ERAs administration, which facilitates prevention and early detection of anemia. ERAs-related anemia is mostly mild, oral iron supplement could effectively reverse anemia and aberrant iron metabolism.

Abstract 4144559: Sex Differences in Vascular Remodeling in Pulmonary Hypertension are mediated by Endothelin-2

Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial vascular remodelingleading to increased pulmonary artery pressure causing right ventricular hypertrophy, failure anddeath. The incidence of PAH is much higher in female patients, indicating that males may have aprotective factor that could help elucidate the pathogenesis of PAH. We have recently demonstratedthat the Y chromosome gene UTY protects against PH development in mice, however the fulldownstream mechanisms remains unknown. By integrating RNA-Seq on whole lung tissues fromUty-KO and WT male mice with a publically available male and female PAH lung microarraydataset, we found increased expression of Endothelin 2 (ET-2) in the lungs of Uty-KO compared toWT mice with PH as well as in the lungs of female patients compared to males with PAH. The roleof ET-1 is known in PAH, and Endothelin receptor antagonists are a common PAH therapy to whichfemale patients are more responsive. However, ET-2 has yet to be investigated in this context. Wevalidated that ET-2 expression is significantly increased in lung tissue from PAH female patientscompared to males. Plasma ET-2 concentration is also significantly higher in PAH patients versuscontrols. Interestingly, plasma ET-2 negatively correlates with pulmonary vascular resistance (PVR)and mean pulmonary arterial pressure (mPAP) in male PAH patients, whereas plasma ET-2significantly positively correlates with PVR and mPAP in female PAH patients. Functionally, wefound that recombinant ET-2 significantly inhibits proliferation of male pulmonary artery endothelialcells (PAECs), but significantly promotes proliferation in female PAECs. Similarly, ET-2 significantlyincreased proliferation of female pulmonary artery smooth muscle cells (PASMC), but not malePASMC. Together, we show that increased ET-2 expression may contribute to worsening PH bypromoting vascular remodeling in the lung and that elevated ET2 in females may at least partiallyexplain the higher incidence of female PAH patients

Enhanced Vasoconstriction in Sickle Cell Disease is Dependent on ETA Receptor Activation.

Sickle Cell Disease (SCD) carries a significant risk for poor vascular health and vascular dysfunction. High levels of vascular reactive oxygen species (ROS) as well as elevated plasma endothelin-1 (ET-1), a potent vasoconstrictor with actions via the ETA receptor, are both common phenotypes in SCD. Alpha-1 adrenergic receptor activation is a major mediator of stress-induced vasoconstriction. However, the mechanism of the SCD enhanced vasoconstrictive response is unknown. We hypothesized that SCD induces enhanced alpha-1 adrenergic mediated vasoconstriction through the ET-1/ETA receptor pathway in arterial tissues. Utilizing humanized SCD (HbSS) and genetic control (HbAA) mice, alpha-1a, but not alpha-1b or alpha-1d, receptor expression was significantly greater in aortic tissue from HbSS mice compared to HbAA mice. Significantly enhanced vasoconstriction in aortic and carotid arterial segments were observed from HbSS mice compared to HbAA mice. Treatment with ambrisentan, a selective ETA receptor antagonist, and a ROS scavenger normalized the aortic vasoconstrictive response in HbSS mice. In a randomized translational study, patients with SCD were treated with placebo or ambrisentan for 3 months, with the treatment group showing an increase in the percent brachial arterial diameter. Taken together, these data suggest that the ETA receptor pathway interaction with the adrenergic receptor pathway contributes to enhanced aortic vasoconstriction in SCD. Findings indicate the potential of ETA antagonism as a therapeutic avenue for improving vascular health in SCD.

Long-Term Safety and Efficacy of Macitentan in Inoperable Chronic Thromboembolic Pulmonary Hypertension: Results from MERIT and its Open-Label Extension.

Evidence for use of pulmonary arterial hypertension targeted-therapies in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is limited. In MERIT-1, the endothelin receptor antagonist macitentan improved hemodynamic and functional parameters versus placebo in patients with inoperable CTEPH over a 24-week double-blind (DB) period. Its open-label (OL) extension study (MERIT-2) provides long-term safety/efficacy data. MERIT-2 (NCT02060721) was a multicenter, single-arm, OL, phase 2 extension study of MERIT-1. Patients completing MERIT-1 were eligible to receive 10 mg macitentan once-daily in MERIT-2. Safety and efficacy (6-min walk distance [6MWD] and change in World Health Organization functional class [WHO FC]) were assessed in all patients in MERIT-2 regardless of treatment received in DB (All patients MERIT-2 OL macitentan 10mg group) and the subgroup of patients receiving DB macitentan in MERIT-1 (Long-term [DB/OL] macitentan 10mg subgroup). Of the 80 patients randomized in MERIT-1, 76 entered MERIT-2 (All patients MERIT-2 OL macitentan 10mg group): 40 who received DB macitentan (DB-macitentan patients) and 36 DB placebo (DB-placebo patients). Median (interquartile range) macitentan exposure in the All patients MERIT-2 OL macitentan 10mg group was 45.5 (26.0, 66.1) months. During the OL period, treatment-emergent adverse events (AE) were reported in 72 (94.7%) patients; most frequent were worsening of pulmonary hypertension (19.7%), decreased hemoglobin (18.4%) and upper respiratory tract infection (15.8%). Fourteen (18.4%) patients died; none were assessed as macitentan-related. At Month 6 post-OL baseline, mean (standard deviation) change in 6MWD was - 0.4m (43.62) for DB-macitentan patients and 10.7m (45.63) for DB-placebo patients; the majority had unchanged (83.3%) or improved (12.5%) WHO FC. Safety/efficacy analyses were consistent in the Long-term (DB/OL) macitentan 10 mg subgroup. These analyses provide long-term safety/efficacy data in patients with inoperable CTEPH treated with macitentan. No unexpected safety findings occurred; reported AEs were consistent with the known safety profile of macitentan. At 6 months post-OL baseline, DB-placebo patients modestly improved 6MWD; DB-macitentan patients maintained improvements observed in MERIT-1. WHO FC was largely unchanged. ClinicalTrials.gov Identifiers: NCT02021292; NCT02060721.

Proteinuria and Progression of Renal Damage: The Main Pathogenetic Mechanisms and Pharmacological Approach

The integrity of the glomerular filtration barrier maintains protein excretion below 150 mg/day. When urinary proteins increase, this indicates damage to the filtration barrier. However, proteinuria is not only a marker of kidney damage but also exacerbates it through various mechanisms involving the glomerular and tubulointerstitial compartments. Therefore, it is essential to intervene with renoprotective action that reduces the proteinuria. In this context, Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are cornerstone treatments. Recent advancements include sodium–glucose cotransporter 2 inhibitors, initially used for glycemic control, now recognized for their renoprotective properties in both diabetic and non-diabetic populations. Another drug, Finerenone, a selective non-steroidal mineralocorticoid receptor antagonist, has emerged as a promising agent, offering anti-inflammatory and antifibrotic benefits with fewer side effects than traditional steroidal options. Finally, dual inhibition of angiotensin II and endothelin-1 receptors through agents like Sparsentan presents a novel approach with significant antiproteinuric effects in IgA nephropathy and focal segmental glomerulosclerosis. This brief review summarizes the mechanisms by which proteinuria promotes kidney damage and the renoprotective therapeutic approaches available, which can be combined with lifestyle modifications and specific treatments for underlying diseases to mitigate the progression of chronic kidney disease.

The effect of the endothelin receptor antagonist atrasentan on insulin resistance in phenotypic clusters of patients with type 2 diabetes and chronic kidney disease.

Type 2 diabetes (T2D) patients with a clinical phenotype characterized by a high degree of insulin resistance are at increased risk of chronic kidney disease (CKD). We previously demonstrated that the endothelin receptor antagonist (ERA) atrasentan reduced insulin resistance in T2D. In this study, we compared the effect of atrasentan on insulin resistance across different phenotypic clusters of patients with T2D. We performed a post hoc analysis of the SONAR trial, a randomized, placebo-controlled trial of the ERA atrasentan in patients with T2D and CKD. Patients were stratified into four previously identified phenotypic clusters: severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD) and mild age-related diabetes (MARD). Changes in insulin resistance, assessed by HOMA-IR, were compared between the phenotypic clusters using a mixed effects model. In total, 931 patients were included in the analysis. In the overall population, atrasentan compared to placebo reduced HOMA-IR by 12.9% [95%CI 3.5,21.4]. This effect of atrasentan was more pronounced in clusters characterized by insulin resistance or deficiency: (SIRD cluster 26.2% [95% CI 3.8,43.3] and SIDD cluster 18.5% [95%CI -3.8,35.9]), although the latter did not reach statistical significance. The effect of atrasentan compared to placebo was less pronounced in the other two clusters (MARD 12.2% [95% CI -1.7,24.12] and MOD -5.3% [95% CI -28.9,13.9]). Atrasentan significantly improved insulin sensitivity in patients with T2D and CKD, especially in those characterized by high insulin resistance (SIRD cluster). Further studies are warranted to investigate the long-term clinical outcomes of atrasentan treatment in these distinct phenotypic clusters.

YAP signaling orchestrates the endothelin-1-guided invadopodia formation in high-grade serous ovarian cancer.

The high-grade serous ovarian cancer (HG-SOC) is a notoriously challenging disease, characterized by a rapid peritoneal dissemination. HG-SOC cells leverage actin-rich membrane protrusions, known as invadopodia, to degrade the surrounding extracellular matrix (ECM) and invade, initiating the metastatic cascade. In HG-SOC, the endothelin-1 (ET-1)/endothelin A receptor (ETAR)-driven signaling coordinates invadopodia activity, however how this axis integrates pro-oncogenic signaling routes, as YAP-driven one, impacting on the invadopodia-mediated ECM degradation and metastatic progression, deserves a deeper investigation. Herein, we observed that downstream of the ET-1/ET-1R axis, the RhoC and Rac1 GTPases, acting as signaling intermediaries, promote the de-phosphorylation and nuclear accumulation of YAP. Conversely, the treatment with the dual ETA/ETB receptor antagonist, macitentan, inhibits the ET-1-driven YAP activity. Similarly, RhoC silencing, or cell transfection with a dominant inactive form of Rac1, restore the YAP phosphorylated and inhibited state. Mechanistically, the ET-1R/YAP signal alliance coordinates invadopodia maturation into ECM-degrading structures, indicating how such ET-1R-guided protein network represents a route able to enhance the HG-SOC invasive potential. At functional level, we found that the interconnection between the ET-1R/RhoC and YAP signals is required for MMP-2 and MMP-9 proteolytic functions, cell invasion, and cytoskeleton architecture changes, supporting the HG-SOC metastatic strength. In HG-SOC patient-derived xenografts (PDX) macitentan, turning-off the invadopodia regulators RhoC/YAP, halt the metastatic colonization. ET-1R targeting, hindering the YAP activity, weakens the invadopodia machinery, embodying a promising therapeutic avenue to prevent peritoneal dissemination in HG-SOC.

IgA Vasculitis (Henoch-Schönlein Purpura): An Update on Treatment.

Objective: IgA vasculitis (IgAV), previously named as Henoch-Schönlein purpura, is the most frequent systemic vasculitis in children. In adults, IgAV is less common although it is associated with more severe disease. In fact, the frequency of glomerulonephritis (referred to as IgAV nephritis) in adults is higher than in children and tends to present more severely, with around 10-30% of those affected eventually progressing to end-stage renal disease. In this review, we describe the pathophysiology, main clinical features, diagnosis of the disease, and latest clinical data regarding IgAV therapy. Methods: A narrative literature review, primarily based on articles published in PubMed, was conducted. In addition to discussing the main aspects of glucocorticoids and conventional disease-modifying drugs used in the management of IgAV, this review focuses on the latest information reported regarding biologics and potential future therapies. Results: Glucocorticoids are the first-line therapy for IgAV, especially in adults with severe manifestations. Colchicine, dapsone, and methotrexate can be useful for controlling minor manifestations. Several immunomodulatory agents, such as cyclosporine A, tacrolimus, and mycophenolate mofetil, have shown favorable results as glucocorticoid-sparing agents. Leflunomide has shown promising results but requires further study. The use of rituximab has demonstrated efficacy in reducing relapse frequency, lowering the cumulative glucocorticoid burden, and achieving long-term remission of the disease in children and adults with IgAV. Immunoglobulins and plasma exchange therapy can also be useful in difficult and life-threatening situations. Other potential therapies with encouraging results include TRF-budesonide, B-cell-directed therapy, B-cell-depleting agents, sodium-glucose cotransporter-2 inhibitors, endothelin receptor antagonists, and complement pathway inhibitors. Conclusions: Glucocorticoids are the first-line therapy for IgAV, especially in adults with severe manifestations. The role of various immunomodulatory therapies, such as calcineurin inhibitors and mycophenolate mofetil, remains promising, while rituximab reduces the long-term side effects of glucocorticoids and can help achieve disease remission. Other potential therapies with encouraging results require further research.

Non-HLA Autoantibodies Against Angiotensin II Receptor 1 (AT1R) and Endothelin A Receptor (ETAR) in Pediatric Kidney Transplantation.

Antibody-mediated rejection (AMR) is the leading cause of premature kidney transplant failure. The role of alloantibodies against Human Leukocyte Antigens (HLA) has been a primary focus in AMR. More recently autoantibodies and alloantibodies against the angiotensin II receptor type 1 (AT1R) and the endothelin A receptor (ETAR) have been linked to poor allograft outcomes in kidney transplantation. Nevertheless, evidence supporting routine testing remains insufficient. ELISA testing for anti-AT1R and anti-ETAR antibodies was performed in a pediatric renal transplant cohort. We selected 12 pediatric recipients who had undergone protocol biopsies and antibody measurements at 6 and 24 months post-transplant. Immunohistochemistry was performed on biopsies for AT1R and ETAR as well as the adhesion molecules ICAM-1 and VCAM-1. The analysis showed that ICAM-1 and VCAM-1 expression was significantly increased, along with the presence of circulating antibodies, in patients at 24 months post-transplant compared to patients without circulating antibodies. The presence of anti-AT1R and anti-ETAR antibodies does not seem to influence the expression of their receptors in the transplanted organ. Instead, the increase in adhesion molecules may precede the development of histological damage. Therefore, enlarging the cohort and extending long-term observation would help to understand the impact of anti-AT1R and anti-ETAR antibodies after transplantation.

The role of angiotensin II and endothelin receptor antibodies in COVID19 patients with HFpEF

Abstract Background The infection caused by the coronavirus SARS-COV-2, is associated with an unusual pattern of organ damage in comparison to other viral-induced pathologies. A theory of autoimmunity induced by ACE-2/SARS-COV-2 spike protein complex or its degradation products, was proposed as a possible explanation for the versatile and multiorgan damage in COVID-19. Aim The aim of the study is to determine whether antibodies against angiotensin II receptor type 1 (AT1R) or endothelin-1 receptor type A (ETAR) do exist in plasma of COVID -19 patients with heart failure with preserved ejection fraction and whether they correlate to the severity of the disease. Methods A total of 61 patients with COVID-19 and heart failure with preserved ejection fraction and 48 controls (free of COVID19) with heart failure with preserved ejection fraction were included. Patients were divided into two groups: patients with severe disease (admitted at the intensive care (n=30)), patients with milder clinical presentation that remained in the general therapeutical department (n=31). The plasma levels of IL-6 and auto-antibodies against AT1R or ETAR in peripheral blood were measured and compared between COVID19 patients with severe and milder disease and age matched controls. Clinical and standard laboratory parameters were also collected and their association with the research biomarkers was analysed. Results Auto-antibodies against AT1R were significantly increased in severe disease course (median 19.60 U/mL, IQR 4.8-34.75) compared to milder disease (median 10.95 U/mL, IQR 7.69 – 17.67, p=0.017) and the control group (median 6.79 U/mL, IQR 5.10 – 14.05, p< 0.001). ETAR antibody titers were also significantly increased in severe disease (median 14.52, IQR 6.76-32.94), compared to milder disease course (median 8.73 U/mL, IQR 6.59 –13.45, p=0.023) and to the control group (median 6.64, IQR 6.79 – 17.92, p <0.001). The same was the trend regarding IL-6 antibodies. Severe disease (median 12.11 U/mL, IQR 5.59–19.38); milder disease disease (median 8.64U/mL, IQR 1.84 – 14.13, p=0.039); control group (median 4.28U/mL, IQR 0.11–1.43, p<0.001).Both AT1R and ETAR correlated to IL-6 plasma levels. The results did not show association with the concomitant therapy. Conclusion In conclusion, we establishеd the presence of AT1R and ETAR autoantibodies in COVID-19 patients with heart failure with preserved ejection fraction. They correlated to IL-6 plasma levels (systemic inflammation) and are associated with severe form of the disease.

Ambrisentan reverses the prosenescent and anti-autophagic effect of high glucose on human pulmonary artery endothelial cells exposed to hypoxia

Abstract Background Cardiovascular (CV) comorbidities (systemic hypertension, hyperlipidemia, obesity, diabetes mellitus, peripheral arterial disease, coronary artery disease) are associated with reduced treatment response to specific drugs for group 1 pulmonary arterial hypertension (PAH). Often this epidemiological evidence is the result of misdiagnosis of group 2 PH associated with left heart disease, but it can also be explained as the intrinsic loss of the ability of pulmonary endothelial cells to respond to specific antiremodeling drugs. Aims To evaluate the impact of high glucose and hyperosmolar stress on the responsiveness of human pulmonary artery endothelial cells (hPAECs) to the endothelin receptor antagonist ambrisentan in terms of senescence, autophagic activity, viability and expression of some microRNAs involved in pulmonary arterial remodeling. Methods We incubated hPAECs with high glucose (HG, 30.5 mM) or high mannitol (HM, 25 mM), with/without ambrisentan (0.02 nM) in normoxia (N) or hypoxia (H) for 24 h and tested them for cell viability (MTT assay), protein and miRNA levels, autophagy and senescence (β-Gal assay) in vitro. Results H induced cell death as compared to N (752 ± 44 vs 701 ± 45 Abs units, p = 0.03). H reduced autophagy (Figure 1A-C) and induced senescence (Figure 1D), an effect further potentiated by HG and HM. Treatment with A in N and H significantly reversed the effect of HG but not HM on autophagy (Figure 1A-C) and senescence (Figure 1D). H increased the abundance of antiapoptotic miR124-3, compared to N in vehicle (V)-treated hPAEC (p=0.008) (Figure 2A), and induced a similar effect on antiapoptotic and proliferative miR191-3p, although not statistically significant (Figure 2B). In N, A potentiated the expression of both miR124-3p (p=0.007) and miR191-3p (p=0.02) in HG-treated hPAEC, and only miR191-3p in HM-treated hPAEC (p=0.01). A induced a similar effect on miR191-3p in hPAEC exposed to H+HG (p=0.02), with a non-statistically significant trend on miR124-3p. Conclusions In hPAEC exposed to H, A retains its pro-autophagic and antisenescent effects in an in vitro model mimicking diabetes. miR124-3p and miR191-3p may act as biomarkers of disease and treatment response to specific drugs in patients with PAH.Figure 1:autophagy and senescenceFigure 2:miRNA expression

Efficacy of specific drug class therapy in pulmonary arterial hypertension associated with HIV, portal hypertension or both: a single Center experience

Abstract Background Pulmonary arterial hypertension (PAH) is a rare complication of both HIV infection (HIV-PAH) and portal hypertension (Po-PAH); it can occur in patients with both diseases (HIV/Po-PAH). The use of the PAH-specific drug classes (prostanoids, endothelin-1 receptor antagonists [ERA] and phosphodiesterase-5 inhibitors [PDE5-i]) is largely justified by retrospective and observational case reports since, to date, there are no randomized clinical trials except for the PORTICO trial which demonstrated the efficacy of macitentan in Po-PAH. Purpose the aim of the study was to evaluate the efficacy of PAH-specific drugs, both monotherapy and dual oral upfront therapy (ERA + PDE5i started within 1 month apart), in patients with Po-PAH, HIV/Po-PAH and HIV-PAH. Methods Between 1998 and 2023 we enrolled patients with Po-PAH, HIV-PAH and HIV/Po-PAH referred to our Center and undergoing monotherapy with prostanoid, ERA and PDE5-I or dual upfront oral therapy. The efficacy of the drugs was assessed by comparing clinical parameters (NYHA functional class), exercise capacity (six-minute walking test) and hemodynamic parameters at baseline and after a treatment period of 3-6 months. The data are expressed as mean and standard deviation and were compared with Student's t-test for paired data. Results 128 patients were enrolled (83 Po-PAH, 23 HIV/Po-PAH and 22 HIV-PAH). 20 were treated with ERA monotherapy, 90 with PDE5-I, 13 with prostanoids and 5 treated with dual oral upfront therapy. Conclusions Prostanoids, ERAs and PDE5-Is, both in monotherapy and as dual upfront oral therapy, are associated with a significant improvement in functional class, exercise capacity and hemodynamic parameters. The effect of such drugs is similar to patients suffering from other forms of PAH.

Angiotensin-II receptor type 1 and endothelin-1 receptor type A agonistic autoantibodies in patients with STEMI: new kids on the block

Abstract Background The Prognosis after ST-elevation myocardial infarction (STEMI) remains poor. Angiotensin-II and endothelin-1 contribute to adverse prognosis after STEMI through molecular mechanisms that lead to myocardial inflammation, fibrosis and, ultimately, adverse myocardial remodeling. Functional autoantibodies against angiotensin II type 1 (AT1R-AAs) and endothelin-1 type A (ETAR-AAs) receptors bind to the same receptors as natural ligands, eliciting similar (and amplified) responses. In patients with STEMI, AT1R-AAs and ETAR-AAs have been associated with a higher risk of developing microvascular obstruction and left ventricular remodeling. Both microvascular obstruction and left ventricular remodeling are associated with a poor prognosis. Purpose To assess the prognostic role of AT1R-AAs and ETAR-AAs after STEMI. Methods Consecutive STEMI patients who underwent primary percutaneous coronary intervention within 12 h after pain onset were enrolled in this prospective study. The levels of AT1R-AAs and ETAR ETAR-AAs at the time of hospital admission were measured using an enzyme-linked immunosorbent assay (ELISA) in all patients. The incidence of major adverse cardiovascular events (MACE, defined as a composite of cardiovascular mortality, myocardial re-infarction, and hospitalizations for heart failure) during follow-up was the primary outcome. Autoantibody seropositivity was defined according to ELISA’s kit manufacturer’s instructions (levels > 10 U/mL). Results Two hundred patients with STEMI were enrolled. The baseline characteristics of the patients are shown in Table 1. Of these, 110 (55%) were seronegative for both autoantibodies, 44 (22%) were seropositive for one autoantibody (but not both), and 46 (23%) were seropositive for both autoantibodies. The incidence of MACE over a 14-month median follow-up was higher in patients with double (31%) and single (25%) seropositivity than in seronegative patients (13%, p=0.009 and p=0.06, respectively). Survival free from MACE was significantly different across the different degrees of autoantibody seropositivity (Figure 1). In the multivariable Cox regression analysis, adjusted for the variables that were significant in the univariate analysis (highlighted in bold in Table 1), double seropositivity was independently associated with an increased risk of MACE (hazard ratio 2.386, 95 % CI 1.471-3.864, p<0.001). Conclusions The degree of seropositivity for AT1R-AAs and ETAR-AAs is associated with an increased risk of MACE after STEMI. Our findings provide valuable mechanistic insights into the pathophysiology of STEMI and pave the way for future therapies focused on the improvement of long-term prognosis after acute coronary syndromes.

Treatment of Systemic Sclerosis Complicated By Cardiac Arrhythmia: A Case Report

Cardiac manifestations are occasionally observed in Systemic Sclerosis patients. Primary cardiac involvement may occur as a direct consequence of the disease. Arrhythmias are also thought to be a direct result from conduction system fibrosis. Early diagnosis and treatment of arrhythmia can be rewarding for this patient as if intreated may lead to a fatal outcome. Beta blockers used to treat arrythmia may worsen Raynaud’s symptom in systemic sclerosis. So there has been a controversy regarding the treatment of arrhythmia in Systemic Sclerosis. Here we are reporting a case of Systemic Sclerosis who presented with palpitation and digital gangrene. Her resting ECG showed multiple premature ventricular complexes whereas echocardiogram did not show any significant abnormality. Then She was treated with non-selective beta blocker without any progression of her Raynaud’s. For her digital gangrene, along with other conventional treatment (like nifedipine & tadalafil) she was treated with endothelin receptor antagonist (bosentan) and showed good response. J Dhaka Med Coll. 2023; 32(1) : 92-95

High Levels of Uric Acid Upregulate Endothelin Receptors: The Role of MAPK Pathways in an in vitro Study

IntroductionUric acid (UA) is the end product of purine compounds' metabolism. There is overwhelming evidence linking hyperuricemia (high levels of UA) and cerebrovascular diseases, but the effect of high levels of UA on cerebral vessels is not fully understood. The aim of this research is to clarify how UA affect the endothelin (ET) receptor in rat cerebral arteries and the related mechanism.Material and methodsIn an in vitro setting, segments of rat cerebral arteries (n=12) were exposed to high levels of UA, either alone or in conjunction with MAPK pathway inhibitors. ET agonists were used to induce contractions that were then measured with a myograph. ET receptor expression was measured using RT-PCR (n=6), Western Blot (n=3), or immunohistochemistry (n=3) to quantify mRNA and protein levels.ResultsThe study revealed that high levels of UA notably increase ETA and ETB receptor-induced contractions and boost the expression of ET receptors in cerebral arteries when compared to that are fresh or cultured alone, suggesting that UA enhances ETA and ETB receptors. Additionally, the up-regulation of ETB receptors induced by UA was inhibited by the p38 inhibitor SB203580, the JNK inhibitor SP600125, and the ERK1/2 inhibitor U0126. SB203580 significantly blocked the increase in ETA receptor-mediated contractions induced by UA and the upregulation of ETA receptor. Neither SP600125 nor U0126 had such effect.ConclusionsHigh levels of UA stimulate the up-regulation of ET receptors in rat cerebral arteries in vitro through MAPK pathways. This study may offer novel perspectives on hyperuricemia-associated cerebrovascular diseases.

The Selective Endothelin Receptor Antagonist SC0062 in IgA Nephropathy: A Randomized Double-Blind Placebo-Controlled Clinical Trial.

Key Points Patients with IgA nephropathy and significant proteinuria are at high risk of progressive kidney function loss and kidney failure.We report the results of a clinical trial assessing the selective endothelin receptor antagonist SC0062 for the treatment of IgA nephropathy.SC0062 led to clinically meaningful improvements in proteinuria and did not increase risk of peripheral edema at higher doses. Background Endothelin receptor type A activation contributes to kidney injury in patients with IgA nephropathy. SC0062 is a novel selective endothelin receptor type A antagonist. We report the results of a phase 2 dose-finding trial to characterize the efficacy and safety of SC0062 in patients with IgA nephropathy. Methods We conducted a randomized, placebo-controlled, double-blind, clinical trial in adults with biopsy-proven IgA nephropathy and eGFR ≥30 ml/min per 1.73 m2 with urinary protein-creatinine ratio (UPCR) ≥0.75 g/g or proteinuria ≥1 g/24 hour despite using maximum tolerated doses of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Patients were randomized 1:1:1:1 to 24-week treatment with SC0062 5, 10, and 20 mg or matching placebo once daily. The primary efficacy outcome was percent change from baseline in UPCR in 24-hour urine samples after 12 weeks of treatment. Secondary end points included changes in eGFR. Safety outcomes including treatment emerging adverse events and serious adverse events were recorded. Results Overall, 131 patients (mean age 42 years [SD, 11]; mean eGFR 72 ml/min per 1.73 m2 [SD 24] and median 24-hour UPCR 1.2 g/g [25th–75th percentile, 0.9–1.5 g/g]) were randomized to placebo (n=34) or SC0062 5 mg (n=33), 10 mg (n=32), or 20 mg (n=32). All SC0062 doses reduced UPCR versus placebo throughout treatment. At week 12, placebo-corrected geometric mean changes (95% confidence interval) from baseline in UPCR with SC0062 5, 10, and 20 mg were−27.6% (−43.0 to −8.2), −20.5% (−37.4 to 1.0), and −38.1% (−51.4 to −21.0), respectively, and at week 24 they were−22.4% (−42.2 to 4.3), −30.9% (−48.6 to −7.0), and −51.6% (−64.2 to −34.6), respectively. No differences in eGFR were observed among treatment groups. The proportion of participants with treatment emerging adverse events or serious adverse events was balanced among treatment groups. Peripheral edema was reported by 2 (6%), 1 (3%), 1 (3%) participants in the 5, 10, and 20 mg SC0062-treated groups, respectively, compared with 5 (15%) in the placebo group. Conclusions In patients with IgA nephropathy, SC0062 reduced proteinuria and did not increase risk of peripheral edema. Clinical Trial registry name and registration number: A Study to Evaluate the Efficacy and Safety of SC0062 in the Treatment of CKD, NCT05687890.