Treatment Of Pulmonary Arterial Hypertension Research Articles

Long-term safety and tolerability of ambrisentan treatment for pediatric patients with pulmonary arterial hypertension: An open-label extension study

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

The nitric oxide-soluble guanylate cyclase-cGMP pathway in pulmonary hypertension: from PDE5 to soluble guanylate cyclase.

The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway plays a key role in the pathogenesis of pulmonary hypertension (PH). Targeted treatments include phosphodiesterase type 5 inhibitors (PDE5i) and sGC stimulators. The sGC stimulator riociguat is approved for the treatment of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). sGC stimulators have a dual mechanism of action, enhancing the sGC response to endogenous NO and directly stimulating sGC, independent of NO. This increase in cGMP production via a dual mechanism differs from PDE5i, which protects cGMP from degradation by PDE5, rather than increasing its production. sGC stimulators may therefore have the potential to increase cGMP levels under conditions of NO depletion that could limit the effectiveness of PDE5i. Such differences in mode of action between sGC stimulators and PDE5i could lead to differences in treatment efficacy between the classes. In addition to vascular effects, sGC stimulators have the potential to reduce inflammation, angiogenesis, fibrosis and right ventricular hypertrophy and remodelling. In this review we describe the evolution of treatments targeting the NO-sGC-cGMP pathway, with a focus on PH.

Integrating Network Pharmacology and Experimental Verification to Explore the Pharmacological Mechanisms of Cordycepin against Pulmonary Arterial Hypertension in Rats.

Pulmonary Arterial Hypertension (PAH) is a fatal disease with high morbidity and mortality. Cordycepin has anti-inflammatory, antioxidant and immune enhancing effects. However, the role of Cordycepin in the treatment of PAH and its mechanism is not clear. The Cordycepin structure and PAH-related gene targets were obtained from public databases. The KEGG and GO enrichment analysis of common targets was performed in DAVID. PPI networks were also mapped using the STRING platform. AutoDock Vina, AutoDockTools, ChemBio3D and Pymol tools were selected for molecular docking of key targets. The therapeutic effects of Cordycepin on PAH were observed in Monocrotaline(MCT)-induced PAH rats and platelet-derived growth factor BB (PDGFBB)-induced rat pulmonary artery smooth muscle cells (PASMCs). The right ventricular systolic pressure (RVSP) was detected. HE staining, Western Blot, Scratch assay, EDU and TUNEL assays were used respectively. Through Network Pharmacology and molecular docking , the Cordycepin-PAH core genes were found to be TP53, AKT1, CASP3, BAX and BCL2L1. In MCT-induced PAH rats, the administration of Cordycepin significantly reduced RVSP, and inhibited pulmonary vascular remodeling. In PDGFBB-induced PASMCs, Cordycepin reduced the migration and proliferation of PASMCs and promoted apoptosis. After the Cordycepin treatment, the protein expressions of TP53, Cleaved CASP3 and BAX were significantly increased, while the protein expressions of p-AKT1 and BCL2L1 were significantly decreased in MCT-PAH rats and PDGFBB-induced PASMCs. This study identified that TP53, AKT1, CASP3, BAX, and BCL2L1 were the potential targets of Cordycepin against PAH by ameliorating pulmonary vascular remodeling, inhibiting the abnormal proliferation and migration of PASMCs and increasing apoptosis of PASMCs. which provided a new understanding of the pharmacological mechanisms of Cordycepin in the treatment of PAH.

Hypusine Signaling Promotes Pulmonary Vascular Remodeling in Pulmonary Arterial Hypertension.

Rationale: The ubiquitous polyamine spermidine is essential for cell survival and proliferation. One important function of spermidine is to serve as a substrate for hypusination, a posttranslational modification process that occurs exclusively on eukaryotic translation factor 5A (eIF5A) and ensures efficient translation of various gene products. Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by progressive obliteration of the small pulmonary arteries (PAs) caused by excessive proliferation of PA smooth muscle cells (PASMCs) and suppressed apoptosis. Objectives: To characterize the role of hypusine signaling in PAH. Methods: Molecular, genetic, and pharmacological approaches were used both invitro and invivo to investigate the role of hypusine signaling in pulmonary vascular remodeling. Measurements and Main Results: Hypusine forming enzymes-deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH)-and hypusinated eukaryotic translation factor 5A are overexpressed in distal PAs and isolated PASMCs from PAH patients and animal models. In vitro, inhibition of DHPS using N1-guanyl-1,7-diaminoheptane or shRNA resulted in a decrease in PAH-PASMC resistance to apoptosis and proliferation. In vivo, inactivation of one allele of Dhps targeted to smooth muscle cells alleviates PAH in mice, and its pharmacological inhibition significantly decreases pulmonary vascular remodeling and improves hemodynamics and cardiac function in two rat models of established PAH. With mass spectrometry, hypusine signaling is shown to promote the expression of a broad array of proteins involved in oxidative phosphorylation, thus supporting the bioenergetic requirements of cell survival and proliferation. Conclusions: These findings support inhibiting hypusine signaling as a potential treatment for PAH.

Induced pluripotent stem cell-derived exosomes attenuate vascular remodelling in pulmonary arterial hypertension by targeting HIF-1α and Runx2.

Pulmonary arterial hypertension (PAH) is characterized by extensive pulmonary arterial remodelling. Although mesenchymal stem cell (MSC)-derived exosomes provide protective effects in PAH, MSCs exhibit limited senescence during in vitro expansion compared with the induced pluripotent stem cells (iPSCs). Moreover, the exact mechanism is not known. In this study, we used murine iPSCs generated from mouse embryonic fibroblasts with triple factor (Oct4, Klf4, and Sox2) transduction to determine the efficacy and action mechanism of iPSC-derived exosomes (iPSC-Exo) in attenuating PAH in rats with monocrotaline (MCT)-induced pulmonary hypertension. Both early and late iPSC-Exo treatment effectively prevented the wall thickening and muscularization of pulmonary arterioles, improved the right ventricular systolic pressure, and alleviated the right ventricular hypertrophy in MCT-induced PAH rats. Pulmonary artery smooth muscle cells (PASMC) derived from MCT-treated rats (MCT-PASMC) developed more proliferative and pro-migratory phenotypes, which were attenuated by the iPSC-Exo treatment. Moreover, the proliferation and migration of MCT-PASMC were reduced by iPSC-Exo with suppression of PCNA, cyclin D1, MMP-1, and MMP-10, which are mediated via the HIF-1α and P21-activated kinase 1/AKT/Runx2 pathways. IPSC-Exo are effective at reversing pulmonary hypertension by reducing pulmonary vascular remodelling and may provide an iPSC-free therapy for the treatment of PAH.

GRK2-YAP signaling is implicated in pulmonary arterial hypertension development.

Pulmonary arterial hypertension (PAH) is characterized by excessive proliferation of small pulmonary arterial vascular smooth muscle cells (PASMCs), endothelial dysfunction, and extracellular matrix remodeling. G protein-coupled receptor kinase 2 (GRK2) plays an important role in the maintenance of vascular tone and blood flow. However, the role of GRK2 in the pathogenesis of PAH is unknown. GRK2 levels were detected in lung tissues from healthy people and PAH patients. C57BL/6 mice, vascular smooth muscle cell-specific Grk2 -knockout mice ( Grk2ΔSM22 ), and littermate controls ( Grk2flox/flox ) were grouped into control and hypoxia mice ( n =8). Pulmonary hypertension (PH) was induced by exposure to chronic hypoxia (10%) combined with injection of the SU5416 (cHx/SU). The expression levels of GRK2 and Yes-associated protein (YAP) in pulmonary arteries and PASMCs were detected by Western blotting and immunofluorescence staining. The mRNA expression levels of Grk2 and Yes-associated protein ( YAP ) in PASMCs were quantified with real-time polymerase chain reaction (RT-PCR). Wound-healing assay, 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, and 5-Ethynyl-2'-deoxyuridine (EdU) staining were performed to evaluate the proliferation and migration of PASMCs. Meanwhile, the interaction among proteins was detected by immunoprecipitation assays. The expression levels of GRK2 were upregulated in the pulmonary arteries of patients with PAH and the lungs of PH mice. Moreover, cHx/SU-induced PH was attenuated in Grk2ΔSM22 mice compared with littermate controls. The amelioration of PH in Grk2ΔSM22 mice was accompanied by reduced pulmonary vascular remodeling. In vitro study further confirmed that GRK2 knock-down significantly altered hypoxia-induced PASMCs proliferation and migration, whereas this effect was severely intensified by overexpression of GRK2 . We also identified that GRK2 promoted YAP expression and nuclear translocation in PASMCs, resulting in excessive PASMCs proliferation and migration. Furthermore, GRK2 is stabilized by inhibiting phosphorylating GRK2 on Tyr86 and subsequently activating ubiquitylation under hypoxic conditions. Our findings suggest that GRK2 plays a critical role in the pathogenesis of PAH, via regulating YAP expression and nuclear translocation. Therefore, GRK2 serves as a novel therapeutic target for PAH treatment.

Evaluation of the Molecular Mechanism of Chlorogenic Acid in the Treatment of Pulmonary Arterial Hypertension Based on Analysis Network Pharmacology and Molecular Docking

Background: Pulmonary arterial hypertension (PAH) is a serious disease characterized by increased pressure in the pulmonary arteries, which can lead to heart failure and death. Chlorogenic acid (CGA) is a natural compound present in several foods and medicinal plants and has been described to exert a therapeutic effect in various diseases. However, its potential therapeutic effect on PAH remains undeciphered. In this study, the potential of CGA for the treatment of PAH was investigated using network pharmacology analysis and molecular docking. Methods: Potential CGA targets were obtained from the SwissTargetPrediction and GeneCards databases. Moreover, potential PAH targets were collected from the GeneCards and DisGNET databases. Then, common targets were selected, and a protein-protein network (PPI) was constructed between common CGA and PAH targets using the STRING database. The common hub targets were selected, and GO enrichment analysis was performed via KEGG using the DAVID 6.8 database. Additionally, molecular docking analysis was performed to investigate the interaction between CGA and these potential therapeutic targets. Results: We obtained 168 potential targets for CGA and 5779 potential targets associated with PAH. Among them, 133 were common to both CGA and PAH. The main hub targets identified through PPI network analysis were TP53, HIF1A, CASP3, IL1B, JUN, MMP9, CCL2, VEGFA, SRC, IKBKB, MMP2, CASP8, NOS3, MMP1, and CASP1. KEGG pathway analysis showed that these hub targets are associated with pathways such as lipid and atherosclerosis, fluid shear stress and atherosclerosis, and the IL-17 signaling pathway. In addition, the molecular docking results showed a high binding affinity between CGA and the 15 hub PAH-associated targets, further supporting its therapeutic potential. Conclusions: This study provides preliminary evidence on the underlying molecular mechanism of CGA in the treatment of PAH. The findings suggest that CGA could be a promising option for the development of new PAH drugs.

The Cavin-1/Caveolin-1 interaction attenuates BMP/Smad signaling in pulmonary hypertension by interfering with BMPR2/Caveolin-1 binding

Caveolin-1 (CAV1) and Cavin-1 are components of caveolae, both of which interact with and influence the composition and stabilization of caveolae. CAV1 is associated with pulmonary arterial hypertension (PAH). Bone morphogenetic protein (BMP) type 2 receptor (BMPR2) is localized in caveolae associated with CAV1 and is commonly mutated in PAH. Here, we show that BMP/Smad signaling is suppressed in pulmonary microvascular endothelial cells of CAV1 knockout mice. Moreover, hypoxia enhances the CAV1/Cavin-1 interaction but attenuates the CAV1/BMPR2 interaction and BMPR2 membrane localization in pulmonary artery endothelial cells (PAECs). Both Cavin-1 and BMPR2 are associated with the CAV1 scaffolding domain. Cavin-1 decreases BMPR2 membrane localization by inhibiting the interaction of BMPR2 with CAV1 and reduces Smad signal transduction in PAECs. Furthermore, Cavin-1 knockdown is resistant to CAV1-induced pulmonary hypertension in vivo. We demonstrate that the Cavin-1/Caveolin-1 interaction attenuates BMP/Smad signaling and is a promising target for the treatment of PAH.

Endothelial periostin regulates vascular remodeling by promoting endothelial dysfunction in pulmonary arterial hypertension

ABSTRACT Pulmonary arterial hypertension (PAH) is characterized by vascular remodeling associated with extracellular matrix (ECM) deposition, vascular cell hyperproliferation, and neointima formation in the small pulmonary artery. Endothelial dysfunction is considered a key feature in the initiation of vascular remodeling. Although vasodilators have been used for the treatment of PAH, it remains a life-threatening disease. Therefore, it is necessary to identify novel therapeutic targets for PAH treatment. Periostin (POSTN) is a secretory ECM protein involved in physiological and pathological processes, such as tissue remodeling, cell adhesion, migration, and proliferation. Although POSTN has been proposed as a potential target for PAH treatment, its role in endothelial cells has not been fully elucidated. Here, we demonstrated that POSTN upregulation correlates with PAH by analyzing a public microarray conducted on the lung tissues of patients with PAH and biological experimental results from in vivo and in vitro models. Moreover, POSTN overexpression leads to ECM deposition and endothelial abnormalities such as migration. We found that PAH-associated endothelial dysfunction is mediated at least in part by the interaction between POSTN and integrin-linked protein kinase (ILK), followed by activation of nuclear factor-κB signaling. Silencing POSTN or ILK decreases PAH-related stimuli-induced ECM accumulation and attenuates endothelial abnormalities. In conclusion, our study suggests that POSTN serves as a critical regulator of PAH by regulating vascular remodeling, and targeting its role as a potential therapeutic strategy for PAH.

In Vitro Experimental Approach for Studying Human Pulmonary Artery Smooth Muscle Cells and Endothelial Cells Proliferation and Migration.

Pulmonary arterial hypertension (PAH) is a severe vascular disease characterized by persistent precapillary pulmonary hypertension, leading to right heart failure and death. Despite intense research in the last decades, PAH remains an incurable disease with high morbidity and mortality. New directions and therapies to improve understanding and treatment of PAH are desperately needed. The pathological mechanisms leading to this fatal disorder remain mostly undetermined, although structural remodeling of the pulmonary vessels is known to be an early feature of PAH. Pulmonary vascular remodeling includes proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs). The use of in vitro approaches is useful to delineate the mechanisms involved in the pathogenesis of PAH and to identify new therapeutic strategies for PAH. In this chapter, we describe protocols for culturing and assessing proliferation and migration of human PASMCs and PAECs.

Modelling and Docking studies of Endothelin receptors ( PAH Inducing proteins) with Bosenten Monohydrate

Pulmonary arterial hypertension (PAH) is a serious disease of pulmonary arteries. When Pulmonary Arterial Hypertension (PAH) develops, blood flow through the pulmonary arteries is restricted and the right side of the heart is put under increasing strain to pump blood through to the lungs. The different changes in the blood vessels raise the pressure and increase the resistance to blood flow through the lungs, making it harder for the heart to pump blood through the lungs. Over time, due to the additional strain, the heart begins to work less effectively and eventually, the right heart can fail (this is known as 'right ventricular failure'). Pulmonary arterial hypertension (PAH) is relatively rare. It is estimated that there are about 30-50 people with PAH for every million of the population. While Pulmonary Arterial Hypertension (PAH) can occur at any age, it is more common in women in their childbearing years and the average age of diagnosis is 36. The exact cause of pulmonary arterial hypertension (PAH) remains unknown. In recent years research has focused particularly on the role of three specific substances that are produced in these cells: prostacyclin, nitric oxide and endothelin. These three agents work together to help the blood to flow smoothly through the heart and lungs and it is thought that an imbalance in levels of one or more of these substances contributes to the development of conditions such as Pulmonary Arterial Hypertension (PAH). This leads to the progressive changes in the vessels and the subsequent rise in pressure. This area of research has led to the development of specific treatments for Pulmonary Arterial Hypertension (PAH).

Liver injury due to endothelin receptor antagonists: a real-world study based on post-marketing drug monitoring data.

Liver injury is the hallmark adverse reaction of endothelin receptor antagonist (ERA). Since the first drug, bosentan has been widely used in clinical practice, hepatotoxicity has been accompanied by the history of ERA. The new ERA has been proven to have a lower liver risk but the current research findings are inconsistent. ERA-based targeted drug combinations are commonly used in the treatment of pulmonary arterial hypertension, where the risk of liver injury is difficult to estimate. This study aimed to compare the correlation between ERA and different ERA combination regimens with liver injury in the real world. This is a retrospective study using data from the Adverse Event Reporting System (Food and Drug Administration AERS, FAERS). The study used proportional imbalance and Bayesian analysis to mine FAERS data from January 2004 to December 2022 to determine the association of three ERAs with liver injury and to further mine the risk of liver injury due to the combination of ERAs with other targeted drugs. In addition, we analyzed the onset time, mortality, and hospitalization rate of liver injury caused by different ERA combination regimens. We screened out 3581 ERA-related liver injury events, of which bosentan (59.82%) had the largest number of cases. The patients with liver injury were mainly female (60.63%), and the age was concentrated between 61 and 75 years (26.75%). According to different signal mining methods, reporting odds ratio (ROR; 3.38, 95% confidence interval = 3.23-3.53), proportional reporting ratio (PRR; 3.22, χ2 = 37.84), Bayesian confidence propagation neural network (BCPNN; 1.68, 95% confidence interval = 1.61), multi-item gamma Poisson shrinker (MGPS; 3.21, 95% confidence interval = 3.09), bosentan had the strongest association with liver injury compared to ambrisentan and macitentan. Furthermore, bosentan + sildenafil [ROR (2.52, 95% confidence interval = 2.23-2.84), PRR (2.44, χ2 = 15.92), BCPNN (1.29, 95% confidence interval = 1.14), MGPS (2.44, 95% confidence interval = 2.21)], bosentan + epoprostenol [ROR (5.39, 95% confidence interval = 4.29-6.77), PRR (4.94, χ2 = 65.18), BCPNN (2.30, 95% confidence interval = 1.83), MGPS (4.94, 95% confidence interval = 4.08)], bosentan + iloprost [ROR (2.70, 95% confidence interval = 2.11-3.45), PRR (2.61, χ2 = 31.03), BCPNN (1.38, 95% confidence interval = 1.08), MGPS (2.61, 95% confidence interval = 2.12)] had a higher risk of liver injury caused by the three ERA combination regimens. The median time to onset of hepatotoxicity associated with all ERA combination regimens was 259 days (interquartile range: 58-716.5 days). Finally, the hospitalization rate for patients experiencing hepatotoxicity with ERA combination regimens was 47.86% and the mortality rate was 12.67%. By mining the FAERS, we analyzed and compared the risk of liver injury related to different ERA and ERA combination regimens, and the onset time and adverse reaction outcomes of all ERA combination regimens. According to the results of the study, bosentan had the highest risk of liver injury and the combination regimens bosentan + sildenafil, bosentan + epoprostenol, and bosentan + iloprost had a stronger risk of liver injury. From the early stages of treatment, we need to regularly monitor the liver function of patients, especially for females and the elderly, and discontinue the suspected drug as soon as the liver injury occurs.

Sotatercept for Pulmonary Arterial Hypertension in the Inpatient Setting.

Patients with pulmonary arterial hypertension (PAH) who are admitted to the hospital pose a challenge to the multidisciplinary healthcare team due to the complexity of the pathophysiology of their disease state and PAH-specific medication considerations. Pulmonary arterial hypertension is a progressive disease that may lead to death as a result of right ventricular (RV) failure. During acute on chronic RV failure it is critical to decrease the pulmonary vascular resistance with the goal of improving RV function and prognosis; therefore, aggressive PAH-treatment based on disease risk stratification is essential. Pulmonary arterial hypertension treatment for acute on chronic RV failure can be impacted by end-organ damage, hemodynamic instability, drug interactions, and PAH medications dosage and delivery. Sotatercept, a first in class activin signaling inhibitor that works on the bone morphogenetic protein/activin pathway is on track for Food and Drug Administration approval for the treatment of PAH based on results of recent trials in where the medication led to clinical and hemodynamic improvements, even when added to traditional PAH-specific therapies. The purpose of this review is to highlight important considerations when starting or continuing sotatercept in patients admitted to the hospital with PAH.

Simplified risk stratification based on cardiopulmonary exercise test: A Spanish two-center experience.

A simplified 4-strata risk stratification approach based on three variables is widespread in pulmonary arterial hypertension (PAH)at follow-up. This study aimed to assess the impact of replacing the 6-min walk test (6MWT)with the peak 02 uptake evaluated by the cardiopulmonary exercise test (CPET)on risk stratification by this scale. We included 180 prevalent patients with PAH from two reference hospitals in Spain, followed up between 2006 and 2022. Patients were included if all the variables of interest were available within a 3-month period on the Spanish Registry of Pulmonary Arterial Hypertension (REHAP):functional class (FC);NT-proBNP;6MWT; and CPET. The original 4-strata model (NT-proBNP,6MWT, FC) identified most patients at low or intermediate-low risk (36.7% and 51.1%, respectively). Notably, the modified scale (NT-proBNP,CPET, FC) improved the identification of patients at intermediate-high risk up to 18.9%, and at high risk up to 1.1% in comparison with the previous 12.2% and 0.0% in the original scale. This new model increased the number of patients correctly classified into higher-risk strata (positive NRI of 0.06), as well as classified more patients without events in lower-risk strata (negative NRI of 0.04). The proposed score showed a slightly superior prognostic capacity compared with the original model (Harrel's C-index 0.717 vs. 0.709). Using O2 uptake instead of distance walked in the 6MWT improves the identification of high-risk patients using the 4-strata scale. This change could have relevant prognostic implications and lead to changes in the specific treatment of PAH.

Long Term Survival of Heritable Pulmonary Arterial Hypertension Associated with Hereditary Hemorrhagic Telangiectasia: A Case Series.

Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disease characterized by recurrent epistaxis, mucocutaneous telangiectasias, and visceral arteriovenous malformations. Multiple genetic mutations have been linked to this rare disease, including ENG, ALK1 (ACVRL1), and MADH4. Pulmonary hypertension is a potential complication of HHT, with the most common phenotypes being World Health Organization (WHO) group 1 heritable pulmonary arterial hypertension (PAH), which is typically associated with ALK1 mutation; WHO group 2 pulmonary hypertension due to high output heart failure from hepatic arteriovenous malformations and/or anemia; and WHO group 2 due to high pulmonary artery wedge pressure. There is scarce evidence to help guide treatment of heritable PAH in HHT, and observational literature suggests that patients with HHT and heritable PAH have a worse prognosis compared to patients with idiopathic PAH. We describe the diagnosis, pulmonary hemodynamics, and detailed treatment courses of three patients with ALK1-associated HHT and PAH, who all exhibited objective clinical improvement with parenteral prostacyclins and oral agents.

Inhibition of DYRK1A attenuates vascular remodeling in pulmonary arterial hypertension via suppressing STAT3/Pim-1/NFAT pathway

ABSTRACT Pulmonary arterial hypertension (PAH) is characterized by progressive vascular remodeling caused by the excessive proliferation and survival of pulmonary artery smooth muscle cells (PASMCs). Dual-specificity tyrosine regulated kinase 1A (DYRK1A) is a pleiotropic kinase involved in the regulation of multiple biological functions, including cell proliferation and survival. However, the role and underlying mechanisms of DYRK1A in PAH pathogenesis remain unclear. We found that DYRK1A was upregulated in PASMCs in response to hypoxia, both in vivo and in vitro. Inhibition of DYRK1A by harmine significantly attenuated hypoxia-induced pulmonary hypertension and pulmonary artery remodeling. Mechanistically, we found that DYRK1A promoted pulmonary arterial remodeling by enhancing the proliferation and survival of PASMCs through activating the STAT3/Pim-1/NFAT pathway, because STAT3 gain-of-function via adeno-associated virus serotype 2 (AAV2) carrying the constitutively active form of STAT3 (STAT3C) nearly abolished the protective effect of harmine on PAH. Collectively, our results reveal a significant role for DYRK1A in pulmonary arterial remodeling and suggest it as a drug target with translational potential for the treatment of PAH.

Formulation, Development, and Evaluation of Bosentan Monohydrate Spray Dried- Solid Dispersion Tablets for Improved Dissolution Profile

Bosentan monohydrate (BM) is utilized for the treatment of pulmonary arterial hypertension, exhibiting poor aqueous solubility and bioavailability. This study aims to enhance the dissolution rate of the drug using Eudragit®EPO through spray drying. The drug and Eudragit®EPO were combined in ratios of 1:1, 1:2, 1:3, 1:4, and 1:5 (w/w) to generate compositions SD1 to SD5. SD5, at a 1:5 drug-to-carrier ratio, demonstrated a statistically significant increase in saturation solubility and drug content. Six tablet formulations (F1 to F6) containing SD5 and tableting excipients were developed and processed. Formulation F2, consisting of 26.36% HPMC K4M and 23.63% MCC, exhibited the highest dissolution and drug release. The probable mechanism underlying BM dissolution in SD involves its amorphous form and the solubilizing effect facilitated by hydrogen bonding between BM and Eudragit®EPO. The carrier's binding effect likely contributed to high tensile strength, low friability, and extended disintegration time. Direct mixing of SD with HPMC might have improved the uniformity of SD within the tablet matrix and the release profile. This study demonstrates the efficacy of spray drying in preparing SD of BM with Eudragit®EPO, potentially enhancing its solubility and stability.

Gut-Lung Axis in Focus: Deciphering the Impact of Gut Microbiota on Pulmonary Arterial Hypertension.

Recent advancements in the understanding of pulmonary arterial hypertension (PAH) have highlighted the significant role of the gut microbiota (GM) in its pathogenesis. This comprehensive review delves into the intricate relationship between the GM and PAH, emphasizing the influence of gut microbial composition and the critical metabolites produced. We particularly focus on the dynamic interaction between the gut and lung, examining how microbial dysbiosis contributes to PAH development through inflammation, altered immune responses, and changes in the gut-lung axis. Noteworthy findings include variations in the ratios of key bacterial groups such as Firmicutes and Bacteroidetes in PAH and the pivotal roles of metabolites like trimethylamine N-oxide (TMAO), short-chain fatty acids (SCFAs), and serotonin in the disease's progression. Additionally, the review elucidates potential diagnostic biomarkers and novel therapeutic approaches, including the use of probiotics and fecal microbiota transplantation, which leverage the gut microbiota for managing PAH. This review encapsulates the current state of research in this field, offering insights into the potential of gut microbiota modulation as a promising strategy in PAH diagnosing and treatment.

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

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. 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). 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). 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.

Modulating NO-GC Pathway in Pulmonary Arterial Hypertension.

The pathogenesis of complex diseases such as pulmonary arterial hypertension (PAH) is entirely rooted in changes in the expression of some vasoactive factors. These play a significant role in the onset and progression of the disease. Indeed, PAH has been associated with pathophysiologic alterations in vascular function. These are often dictated by increased oxidative stress and impaired modulation of the nitric oxide (NO) pathway. NO reduces the uncontrolled proliferation of vascular smooth muscle cells that leads to occlusion of vessels and an increase in pulmonary vascular resistances, which is the mainstay of PAH development. To date, two classes of NO-pathway modulating drugs are approved for the treatment of PAH: the phosphodiesterase-5 inhibitors (PD5i), sildenafil and tadalafil, and the soluble guanylate cyclase activator (sGC), riociguat. Both drugs provide considerable improvement in exercise capacity and pulmonary hemodynamics. PD5i are the recommended drugs for first-line PAH treatment, whereas sGCs are also the only drug approved for the treatment of resistant or inoperable chronic thromboembolic pulmonary hypertension. In this review, we will focus on the current information regarding the nitric oxide pathway and its modulation in PAH.