Characteristics and outcomes of patients developing pulmonary hypertension associated with proteasome inhibitors.

BACKGROUND: Pulmonary arterial hypertension (PAH) has been described in patients treated with proteasome inhibitors (PIs). Our objective was to evaluate the association between PIs and PAH. METHODS: Characteristics of incident PAH cases previously treated with carfilzomib or bortezomib were analysed from the French pulmonary hypertension registry and the VIGIAPATH programme from 2004 to 2023, concurrently with a pharmacovigilance disproportionality analysis using the World Health Organization (WHO) global database (VigiBase) and a meta-analysis of randomised controlled trials. RESULTS: 11 incident cases of PI-associated PAH were identified (six with carfilzomib and five with bortezomib) with a female:male ratio of 2.7:1, a median age of 61 years, and a median delay between PI first exposure and PAH of 6 months. Four patients died (two from right heart failure, one from respiratory distress and one from an unknown cause). At diagnosis, six were in New York Heart Association Functional Class III/IV with severe haemodynamic impairment (median mean pulmonary arterial pressure 39 mmHg, cardiac index 2.45 L·min-1·m-2 and pulmonary vascular resistance 7.2 WU). In the WHO pharmacovigilance database, 169 cases of PH associated with PI were reported since 2013 with significant signals of disproportionate reporting (SDR) for carfilzomib, regardless of the definition of cases or control group. However, SDR for bortezomib were inconsistent. The systematic review identified 17 clinical trials, and carfilzomib was associated with a significantly higher risk of dyspnoea, severe dyspnoea and PH compared with bortezomib. CONCLUSION: PIs may induce PAH in patients undergoing treatment, with carfilzomib emitting a stronger signal than bortezomib, and these patients should be monitored closely.

Effects of nitric oxide inhalation on pulmonary arterial impedance: differences between normal and pulmonary hypertension male rats.

Nitric oxide (NO) inhalation improves pulmonary hemodynamics in participants with pulmonary arterial hypertension (PAH). Although it can reduce pulmonary vascular resistance (PVR) in PAH, its impact on the dynamic mechanics of pulmonary arteries and its potential difference between control and participants with PAH remain unclear. PA impedance provides a comprehensive description of PA mechanics. With an arterial model, PA impedance can be parameterized into peripheral pulmonary resistance (Rp), arterial compliance (Cp), characteristic impedance of the proximal arteries (Zc), and transmission time from the main PA to the reflection site. This study investigated the effects of inhaled NO on PA impedance and its associated parameters in control and monocrotaline-induced pulmonary arterial hypertension (MCT-PAH) male rats (6/group). Measurements were obtained at baseline and during NO inhalation at 40 and 80 ppm. In both groups, NO inhalation decreased PVR and increased the left atrial pressure. Notably, its impact on PA impedance was frequency dependent, as revealed by reduced PA impedance modulus in the low-frequency range below 10 Hz, with little effect on the high-frequency range. Furthermore, NO inhalation attenuated Rp, increased Cp, and prolonged transmission time without affecting Zc. It reduced Rp more pronouncedly in MCT-PAH rats, whereas it increased Cp and delayed transmission time more effectively in control rats. In conclusion, the therapeutic effects of inhaled NO on PA impedance were frequency dependent and may differ between the control and MCT-PAH groups, suggesting that the effect on the mechanics differs depending on the pathological state.NEW & NOTEWORTHY Nitric oxide inhalation decreased pulmonary arterial impedance in the low-frequency range (<10 Hz) with little impact on the high-frequency range. It reduced peripheral pulmonary resistance more pronouncedly in pulmonary hypertension rats, whereas it increased arterial compliance and transmission time in control rats. Its effect on the mechanics of the pulmonary arteries may differ depending on the pathological status.

Canagliflozin inhibits PASMCs proliferation via regulating SGLT1/AMPK signaling and attenuates artery remodeling in MCT-induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) was a devastating disease characterized by artery remodeling, ultimately resulting in right heart failure. The aim of this study was to investigate the effects of canagliflozin (CANA), a sodium-glucose cotransporter 2 inhibitor (SGLT2i) with mild SGLT1 inhibitory effects, on rats with PAH, as well as its direct impact on pulmonary arterial smooth muscle cells (PASMCs). PAH rats were induced by injection of monocrotaline (MCT) (40 mg/kg), followed by four weeks of treatment with CANA (30 mg/kg/day) or saline alone. Pulmonary artery and right ventricular (RV) remodeling and dysfunction in PAH were alleviated with CANA, as assessed by echocardiography. Hemodynamic parameters and structural of pulmonary arteriole, including vascular wall thickness and wall area, were reduced by CANA. RV hypertrophy index, cardiomyocyte hypertrophy, and fibrosis were decreased with CANA treatment. PASMCs proliferation was inhibited by CANA under stimulation by platelet-derived growth factor (PDGF)-BB or hypoxia. Activation of AMP kinase (AMPK) was induced by CANA treatment in cultured PASMCs in a time- and concentration-dependent manner. These effects of CANA were attenuated when treatment with compound C, an AMPK inhibitor. Abundant expression of SGLT1 was observed in PASMCs and pulmonary arteries, while SGLT2 expression was undetectable. SGLT1 increased in response to PDGF-BB or hypoxia stimulation, while PASMCs proliferation was inhibited and beneficial effects of CANA were counteracted by knockdown of SGLT1. Our research demonstrated for the first time that CANA inhibited the proliferation of PASMCs by regulating SGLT1/AMPK signaling and thus exerted an anti-proliferative effect on MCT-induced PAH.

Effect of IL-17 on pulmonary artery smooth muscle cells and connective tissue disease-associated pulmonary arterial hypertension.

OBJECTIVE: To explore the role of interleukin (IL)-17 in connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) and to investigate its possible mechanism on pulmonary artery smooth muscle cells (PASMCs). METHODS: Enzyme-linked immunosorbent assay (ELISA) were used to compare levels of serum IL-17 in patients with CTD-PAH and healthy controls (HCs). After treatment for 3 months, the serum IL-17 levels were tested in CTD-PAH. ELISA and immunohistochemistry were used to compare levels of serum IL-17 and numbers of pulmonary artery IL-17+ cells, respectively, in a rat model of monocrotaline-induced PAH and untreated rats. Proliferation, migration, and inflammatory factors expression of PASMCs were assessed after stimulation with different concentrations of IL-17 for various time periods. Proteins in the mitogen-activated protein kinase (MAPK) pathway were examined by western blot. RESULTS: Levels of IL-17 were upregulated in patients with CTD-PAH compared to HCs. After 3 months of treatment, serum IL-17 levels were downregulated with pulmonary artery pressure amelioration. Moreover, serum IL-17 levels and numbers of IL-17+ cells infiltrating lung arterioles were increased in PAH model rats. IL-17 could dose- and time-dependently promote proliferation and migration of PASMCs as well as time-dependently induce IL-6 and intercellular cell adhesion molecule-1 (ICAM-1) expression. The levels of MKK6 increased after IL-17 treatment. Inhibition of MAPK decreased proliferation of PASMCs. CONCLUSION: Levels of IL-17 may increase in CTD-PAH, and IL-17 promotes proliferation, migration, and secretion of IL-6 and ICAM in PASMCs, respectively, which likely involves the p-38 MAPK pathway.

Role of KCNK3 Dysfunction in Dasatinib-associated Pulmonary Arterial Hypertension and Endothelial Cell Dysfunction.

Pulmonary arterial (PA) hypertension (PAH) is a severe cardiopulmonary disease that may be triggered by exposure to drugs such as dasatinib or facilitated by genetic predispositions. The incidence of dasatinib-associated PAH is estimated at 0.45%, suggesting individual predispositions. The mechanisms of dasatinib-associated PAH are still incomplete. We discovered a KCNK3 gene (Potassium channel subfamily K member 3; coding for outward K+ channel) variant in a patient with dasatinib-associated PAH and investigated the impact of this variant on KCNK3 function. Additionally, we assessed the effects of dasatinib exposure on KCNK3 expression. In control human PA smooth muscle cells (hPASMCs) and human pulmonary endothelial cells (hPECs), we evaluated the consequences of KCNK3 knockdown on cell migration, mitochondrial membrane potential, ATP production, and in vitro tube formation. Using mass spectrometry, we determined the KCNK3 interactome. Patch-clamp experiments revealed that the KCNK3 variant represents a loss-of-function variant. Dasatinib contributed to PA constriction by decreasing KCNK3 function and expression. In control hPASMCs, KCNK3 knockdown promotes mitochondrial membrane depolarization and glycolytic shift. Dasatinib exposure or KCNK3 knockdown reduced the number of caveolae in hPECs. Moreover, KCNK3 knockdown in control hPECs reduced migration, proliferation, and in vitro tubulogenesis. Using proximity labeling and mass spectrometry, we identified the KCNK3 interactome, revealing that KCNK3 interacts with various proteins across different cellular compartments. We identified a novel pathogenic variant in KCNK3 and showed that dasatinib downregulates KCNK3, emphasizing the relationship between dasatinib-associated PAH and KCNK3 dysfunction. We demonstrated that a loss of KCNK3-dependent signaling contributes to endothelial dysfunction in PAH and glycolytic switch of hPASMCs.

Spermidine attenuates monocrotaline-induced pulmonary arterial hypertension in rats by inhibiting purine metabolism and polyamine synthesis-associated vascular remodeling.

Ensuring the homeostatic integrity of pulmonary artery endothelial cells (PAECs) is essential for combatting pulmonary arterial hypertension (PAH), as it equips the cells to withstand microenvironmental challenges. Spermidine (SPD), a potent facilitator of autophagy, has been identified as a significant contributor to PAECs function and survival. Despite SPD's observed benefits, a comprehensive understanding of its protective mechanisms has remained elusive. Through an integrated approach combining metabolomics and molecular biology, this study uncovers the molecular pathways employed by SPD in mitigating PAH induced by monocrotaline (MCT) in a Sprague-Dawley rat model. The study demonstrates that SPD administration (5 mg/kg/day) significantly corrects right ventricular impairment and pathological changes in pulmonary tissues following MCT exposure (60 mg/kg). Metabolomic profiling identified a purine metabolism disorder in MCT-treated rats, which SPD effectively normalized, conferring a protective effect against PAH progression. Subsequent in vitro analysis showed that SPD (0.8 mM) reduces oxidative stress and apoptosis in PAECs challenged with Dehydromonocrotaline (MCTP, 50 µM), likely by downregulating purine nucleoside phosphorylase (PNP) and modulating polyamine biosynthesis through alterations in S-adenosylmethionine decarboxylase (AMD1) expression and the subsequent production of decarboxylated S-adenosylmethionine (dcSAM). These findings advocate SPD's dual inhibitory effect on PNP and AMD1 as a novel strategy to conserve cellular ATP and alleviate oxidative injuries, thus providing a foundation for SPD's potential therapeutic application in PAH treatment.

Hydroxy-Safflower Yellow A Mitigates Vascular Remodeling in Rat Pulmonary Arterial Hypertension.

Purpose: The underlying causes of pulmonary arterial hypertension (PAH) often remain obscure. Addressing PAH with effective treatments presents a formidable challenge. Studies have shown that Hydroxysafflor yellow A (HSYA) has a potential role in PAH, While the mechanism underlies its protective role is still unclear. The study was conducted to investigate the potential mechanisms of the protective effects of HSYA. Methods: Using databases such as PharmMapper and GeneCards, we identified active components of HSYA and associated PAH targets, pinpointed intersecting genes, and constructed a protein-protein interaction (PPI) network. Core targets were singled out using Cytoscape for the development of a model illustrating drug-component-target-disease interactions. Intersection targets underwent analysis for Gene Ontology (GO) functions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Selected components were then modeled for target interaction using Autodock and Pymol. In vivo validation in a monocrotaline-induced PAH (MCT-PAH) animal model was utilized to substantiate the predictions made by network pharmacology. Results: We associated HSYA with 113 targets, and PAH with 1737 targets, identifying 34 mutual targets for treatment by HSYA. HSYA predominantly affects 9 core targets. Molecular docking unveiled hydrogen bond interactions between HSYA and several PAH-related proteins such as ANXA5, EGFR, SRC, PPARG, PGR, and ESR1. Conclusion: Utilizing network pharmacology and molecular docking approaches, we investigated potential targets and relevant human disease pathways implicating HSYA in PAH therapy, such as the chemical carcinogenesis receptor activation pathway and the cancer pathway. Our findings were corroborated by the efficacious use of HSYA in an MCT-induced rat PAH model, confirming its therapeutic potential.

Overview of Methamphetamine-Associated Pulmonary Arterial Hypertension.

TOPIC IMPORTANCE: The global surge in methamphetamine use is a critical public health concern, particularly due to its robust correlation with methamphetamine-associated pulmonary arterial hypertension (MA-PAH). This association raises urgent alarms about the potential escalation of MA-PAH incidence, posing a significant and imminent challenge to global public health. REVIEW FINDINGS: This comprehensive review meticulously explores MA-PAH, offering insights into its epidemiology, pathophysiology, clinical presentation, diagnostic intricacies, and management strategies. The pathogenesis, yet to be fully described, involves complex molecular interactions, including alterations in serotonin signaling, reduced activity of carboxylesterase 1, oxidative stress, and dysregulation of pulmonary vasoconstrictors and vasodilators. These processes culminate in the structural remodeling of the pulmonary vasculature, resulting in pulmonary arterial hypertension. MA-PAH exhibits a more severe clinical profile in functional class and hemodynamics compared with idiopathic pulmonary arterial hypertension. Management involves a multifaceted approach, integrating pulmonary vasodilators, cessation of methamphetamine use, and implementing social and rehabilitation programs. These measures aim to enhance patient outcomes and detect potential relapses for timely intervention. SUMMARY: This review consolidates our understanding of MA-PAH, pinpointing knowledge gaps for future studies. Addressing these gaps is crucial for advancing diagnostic accuracy, unraveling mechanisms, and optimizing treatment for MA-PAH, thereby addressing the evolving landscape of this complex health concern.

Effect of Benidipine Alone and in Combination With Bosentan and Sildenafil in Amelioration of Pulmonary Arterial Hypertension in Experimental Model in Rats.

ABSTRACT: Pulmonary arterial hypertension (PAH) is a persistent condition affecting the pulmonary arteries' endothelium. Benidipine, a calcium channel blocker, possesses vasodilatory, anti-inflammatory activity, reduces oxidative stress, and inhibits the activity of Transforming growth factor-ß (TGF-ß) and α-smooth muscle actin (α-SMA). The present study was designed to investigate the effect of benidipine alone and in combination with bosentan and sildenafil on monocrotaline (MCT)-induced pulmonary hypertension in a rat model. PAH was induced by a single-dose administration of MCT in rats. Animals were randomized into different groups and treated with benidipine alone and in combination with bosentan or sildenafil. Various parameters such as hemodynamic parameters, Fulton's index and oxidative stress parameters were performed. Additionally, histopathology of lung and right ventricular of heart tissue, immunohistochemistry, expression of α-SMA, endothelial nitric oxide synthase (eNOS), TGF-ß, and RT-PCR, and an in vitro study using human umbilical vein endothelial cells (HUVECs) was also carried out. Treatment of benidipine and its combination exhibited better prevention in the elevated right ventricular systolic pressure, right ventricular hypertrophy, rise in oxidative stress, and increase in expression of α-SMA and TGF-ß receptor 1 compared with MCT control group rats. In HUVECs, the expression of α-SMA was increased, whereas that of eNOS decreased after TGF-ß exposure and was substantially reversed after pretreatment with benidipine. We concluded that benidipine and its combination with bosentan and sildenafil exhibit beneficial effects in MCT-induced PAH through the eNOS/TGF-ß/α-SMA signaling pathway.

In vivo pharmacokinetic study of vanillic acid in monocrotaline-induced pulmonary arterial hypertension rats and its tissue distribution.

Vanillic acid (VA) is a bioactive chemical present in many food plants and fruits. It has been shown to have a protective effect on pulmonary tissues in monocrotaline-induced pulmonary arterial hypertension, as well as an intervention effect on right ventricular remodeling. The purpose of this study was to develop and test a reliable method for assessing VA utilizing ultra-performance liquid chromatography-high resolution mass spectrometry using caffeic acid as the internal standard. Across diverse substrates, the correlation coefficient for VA ranged from 0.9992 to 0.9995. The method's intraday precision was <13.53% (RSD), and its accuracy (RE) ranged from -9.88 to 4.35%. The precision across days was <13.69% (RSD), while the accuracy ranged from 2.16 to 10.94% (RE). The extraction recoveries ranged from 80.30 to 118.81%, with a lower limit of quantification of 20 ng/mL. The approach was successfully applied to pharmacokinetic and tissue distribution studies of VA in rat plasma after gavage administration, and the pharmacokinetic parameters of VA in the plasma of the monocrotaline-induced pulmonary arterial hypertension were significantly different from those of the control group.

The novel roles of YULINK in the migration, proliferation and glycolysis of pulmonary arterial smooth muscle cells: implications for pulmonary arterial hypertension.

BACKGROUND: Abnormal remodeling of the pulmonary vasculature, characterized by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) along with dysregulated glycolysis, is a pathognomonic feature of pulmonary arterial hypertension (PAH). YULINK (MIOS, Entrez Gene: 54468), a newly identified gene, has been recently shown to possess pleiotropic physiologic functions. This study aims to determine novel roles of YULINK in the regulation of PAH-related pathogenesis, including PASMC migration, proliferation and glycolysis. RESULTS: Our results utilized two PAH-related cell models: PASMCs treated with platelet-derived growth factor (PDGF) and PASMCs harvested from monocrotaline (MCT)-induced PAH rats (PAH-PASMCs). YULINK modulation, either by knockdown or overexpression, was found to influence PASMC migration and proliferation in both models. Additionally, YULINK was implicated in glycolytic processes, impacting glucose uptake, glucose transporter 1 (GLUT1) expression, hexokinase II (HK-2) expression, and pyruvate production in PASMCs. Notably, YULINK and GLUT1 were observed to colocalize on PASMC membranes under PAH-related pathogenic conditions. Indeed, increased YULINK expression was also detected in the pulmonary artery of human PAH specimen. Furthermore, YULINK inhibition led to the suppression of platelet-derived growth factor receptor (PDGFR) and the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K), and protein kinase B (AKT) in both cell models. These findings suggest that the effects of YULINK are potentially mediated through the PI3K-AKT signaling pathway. CONCLUSIONS: Our findings indicate that YULINK appears to play a crucial role in the migration, proliferation, and glycolysis in PASMCs and therefore positioning it as a novel promising therapeutic target for PAH.

Methamphetamine-associated pulmonary arterial hypertension: data from the national biological sample and data repository for pulmonary arterial hypertension (PAH Biobank).

OBJECTIVE: This study compares the clinical and haemodynamic severity of methamphetamine-associated pulmonary arterial hypertension (MA-PAH) with idiopathic pulmonary arterial hypertension (IPAH) and connective tissue-associated pulmonary arterial hypertension (CTD-PAH). It also examines sex differences in clinical and physiological parameters among those with MA-PAH. DESIGN: This is a cross-sectional study using clinically derived data from the National Biological Sample and Data Repository for Pulmonary Arterial Hypertension (PAH biobank), a US-based registry, to compare clinical and physiological characteristics between males and females with MA-PAH. POPULATION: The analysis included 1830 patients enrolled in the PAH biobank, with a diagnosis of MA-PAH (n=42), IPAH (n=1073), or CTD-PAH (n=715). MAIN OUTCOME MEASURES: The study assessed and compared the clinical and haemodynamic parameters of patients with MA-PAH, IPAH and CTD-PAH. RESULTS: Among the patients analysed, 42 had MA-PAH, with 69.1% being female. There were no statistically significant differences in functional class among patients with MA-PAH, IPAH and CTD-PAH. The per cent predicted 6-min walk distance (6MWD) was comparable between the three groups. Patients with MA-PAH had similar mean pulmonary artery pressure and pulmonary vascular resistance to patients with IPAH but higher compared with patients with CTD-PAH. Male patients with MA-PAH exhibited a worse functional class and lower per cent predicted 6MWD, but no significant differences in haemodynamic findings were observed between the sexes. CONCLUSION: There were no differences in haemodynamic between MA-PAH and IPAH but we found that MA-PAH differed from CTD-PAH. The study did not find evidence of sex differences in MA-PAH. Further research is necessary to identify risk factors and underlying mechanisms of MA-PAH, particularly considering the increasing prevalence of methamphetamine use. Such investigations will contribute to the development of effective prevention and treatment strategies for this condition.

Pinocembrin attenuates susceptibility to atrial fibrillation in rats with pulmonary arterial hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a disease characterized by pulmonary vascular remodeling that triggers fibrosis and excessive myocardium apoptosis, ultimately facilitating atrial fibrillation (AF). In various rat models, Pinocembrin has anti-fibrotic and anti-apoptotic effects, reducing arrhythmia vulnerability. However, whether pinocembrin alleviates to AF in a PAH model remains unclear. The experiment aims to investigate how pinocembrin affects AF susceptibility in PAH rats and the possible mechanisms involved. METHODS: The PAH model was induced by monocrotaline (MCT; i. p. 60 mg/kg). Concurrently, rats received pinocembrin (i.p.50 mg/kg) or saline. Hemodynamics parameters, electrocardiogram parameters, lung H.E. staining, atrial electrophysiological parameters, histology, Western blot, and TUNEL assay were detected. RESULTS: Compared to the control rats, MCT-induced PAH rats possessed prominently enhancive mPAP (mean pulmonary artery pressure), pulmonary vascular remodeling, AF inducibility, HRV, right atrial myocardial fibrosis, apoptosis, atrial ERP, APD, and P-wave duration. Additionally, there were lowered protein levels of Cav1.2, Kv4.2, Kv4.3, and connexin 40 (CX40) in the MCT group in right atrial tissue. However, pinocembrin reversed the above pathologies and alleviated the activity of the Rho A/ROCKs signaling pathway, including the expression of Rho A, ROCK1, ROCK2, and its downstream MYPT-1, LIMK2, BCL-2, BAX, cleaved-caspase3 in right atrial and HL-1 cells. CONCLUSION: Present data exhibited pinocembrin attenuated atrial electrical, ion-channel, and autonomic remodeling, diminished myocardial fibrosis and apoptosis levels, thereby reducing susceptibility to AF in the MCT-induced PAH rats. Furthermore, we found that pinocembrin exerted inhibitory action on the Rho A/ROCK signaling pathway, which may be potentially associated with its anti-AF effects.

Safety and effectiveness of ambrisentan in real clinical practice in pulmonary arterial hypertension: Results from the Korean post-marketing surveillance.

PURPOSE: This regulatory post-marketing surveillance (PMS) was organized to identify the safety and effectiveness of ambrisentan in the Korean population. METHOD: This was an open-label, multi-center PMS conducted from 31 institutions in Korea for 6 years from August 2015 to 2021, to evaluate the use of ambrisentan for the treatment of pulmonary arterial hypertension (PAH). Inclusion criteria are Korean subjects with the World Health Organization functional classification (WHO Fc) II or III PAH who are new users or repeated users with ambrisentan (Volibris®) Tablet 5 or 10 mg per day (age >18 years old). RESULTS: A total of 293 cases were analyzed. The overall incidence of adverse events (AE) was 52.22% and adverse drug reactions (ADR) was 10.92%. Severe AEs occurred in 20.82% of patients. However, only 2 subjects (0.68%) reported serious ADR. The difference in AE incidence was statistically significant for concomitant medications other than PAH medications in the safety analysis and the new users (p = 0.0041 and p = 0.0299, respectively) and elderly population in the repeated users (p = 0.0319). Among the long-term 223 subjects, the WHO Fc II and III were 41.26% and 58.74% before ambrisentan, and changed after treatment to 3.09%, 66.05%, and 30.86% for Fc I/II/III, respectively. 217 of 249 subjects (87.15%) considered their symptoms to have 'improved' after the last administration. CONCLUSION: In real-world practice, ambrisentan demonstrated tolerable safety and favorable effectiveness in PAH patients in Korea. Age and concomitant drug use can affect the occurrence of AE.

Development of novel bosentan analogues as endothelin receptor antagonists for pulmonary arterial hypertension.

Since decades, bosentan has been in use for the treatment of pulmonary arterial hypertension (PAH). However, chronic exposure to bosentan leads to the development of resistance, tolerance, and serious adverse effects that have restricted its usage in clinical practices. To surmount these limitations, some new bosentan derivatives have been synthesized and evaluated for their therapeutic efficacy in PAH. Molecular docking analyses of all the synthesized derivatives were carried out using the endothelin (ET) receptor. In addition, the inhibitory ability of synthesized derivatives was determined in in vitro assay employing an ET-1 human ELISA kit. Among the synthesized derivatives, three derivatives namely 17d, 16j, and 16h with higher docking scores and lower IC50 values were selected for determination of the magnitude of the binding force between the derivative and ET receptor using molecular dynamics (MD) simulations study. Further, these derivatives were subjected to in vivo studies using monocrotaline (MCT) induced PAH in rat model. Results of in vivo studies inferred that the derivatives exhibit impressive ability to reduce PAH. Besides, its protective role was also evidenced in hemodynamic and right ventricular hypertrophy analyses, histological analysis, cardiac biomarkers, hypoxia-inducible factor 1 alpha (HIF1α) levels, and biochemical studies. Furthermore, gene quantification by quantitative RT-PCR and Western blot analysis was also performed to examine its effect on the expression of key proteins in PAH. Notably, amongst three, derivative 16h exhibited the most encouraging results in molecular docking analysis, in vitro, in vivo, histopathological, biochemical, protein expression, and MD studies. Besides, derivative 16h also showed impressive pharmacokinetic features in ADMET analysis. In conclusion, derivative 16 h could act as a reliable ET receptor antagonist and requires further exploration to attain its therapeutic utility in PAH management.

Nobiletin attenuates monocrotaline-induced pulmonary arterial hypertension through PI3K/Akt/STAT3 pathway.

OBJECTIVES: Nobiletin is a flavonoid found in the peel of Citrus sinensis (oranges). The purpose of this study is to investigate whether Nobiletin can alleviate the monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) and explore the underlying mechanisms. METHODS: The PAH rat model was replicated by subcutaneous injection of MCT. Nobiletin (1, 5 and 10 mg/kg) was administered by gavage from day 1 to day 21. After 21 days of MCT injection, the mean pulmonary artery pressure, pulmonary vascular resistance, Fulton Index, pulmonary artery remodelling, blood routine parameters, liver and kidney functions was measured. The level of inflammatory cytokines and PI3K/Akt/STAT3 were detected by qPCR, ELISA and western blot, the proliferation of pulmonary artery smooth muscle cells (PASMCs) was evaluated by CCK-8. KEY FINDINGS: Nobiletin (10 mg/kg) inhibited the MCT-induced increase in mean pulmonary artery pressure and pulmonary vascular resistance, right ventricular hypertrophy and pulmonary artery remodelling in rats. Nobiletin decreased the levels of inflammatory cytokines and phosphorylation level of PI3K/Akt/STAT3 in lungs of MCT-treated rats. Nobiletin inhibited the proliferation and lowered the inflammatory cytokines level induced by PDGF-BB in PASMCs. CONCLUSION: Nobiletin attenuates MCT-induced PAH, and the potential mechanism is to inhibit inflammation through PI3K/Akt/STAT3 pathway.

Comparative evaluation of costs and healthcare resource utilization of oral selexipag versus inhaled treprostinil or oral treprostinil in patients with pulmonary arterial hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH), a rare vasculopathy progressively leading to right heart failure and death, is associated with considerable economic burden. Oral prostacyclin pathway agents (PPAs) like selexipag and treprostinil address an underlying PAH pathway, yet are often under-utilized. Data on head-to-head cost comparison of various PPAs is lacking. METHODS: In this retrospective study using a large health claims database, we compared the per-patient-per-year (PPPY) costs and healthcare resource utilization (HRU) among PAH patients taking either oral selexipag, inhaled treprostinil or oral treprostinil in the United States between July 2015 and March 2020. Patients with ≥1 prescription for one of the drugs of interest, ≥1 in-patient pulmonary hypertension (PH) diagnosis, or ≥ 2 outpatient PH diagnoses were included in this study. Baseline differences between the three groups were adjusted using an inverse probability of treatment weighting approach. 411 patients were selected for the final study cohorts. RESULTS: All-cause hospitalization costs were highest for oral treprostinil ($39,983) compared to oral selexipag ($20,635) and inhaled treprostinil ($16,548; p = .037). Total PAH-related medical costs were 40% lower for patients on oral selexipag compared to patients on oral and inhaled treprostinil ($24,351 vs. $40,398 and $40,339, respectively; p = .006). PAH-related outpatient visits were lowest for patients on oral selexipag (14 PPPY visits) compared to oral treprostinil (16 PPPY visits) and inhaled treprostinil (22 PPPY visits; p = .001). CONCLUSIONS: Compared to oral and inhaled treprostinil, oral selexipag may incur lower medical costs and reduce PAH related outpatient visits for patients with PAH.

Shikonin improves pulmonary vascular remodeling in monocrotaline­induced pulmonary arterial hypertension via regulation of PKM2.

Pulmonary arterial hypertension (PAH), a fatal disease with an insidious onset and rapid progression, shows characteristics such as increases in pulmonary circulatory resistance and pulmonary arterial pressure, and progressive right heart failure. Shikonin can reduce right ventricular systolic pressure in chronically hypoxic mice. However, the mechanisms underlying the protective effect of shikonin against PAH pathogenesis have only been sporadically identified. The present study evaluated whether inhibiting the expression of pyruvate kinase M2 (PKM2) contributed to the improvement of pulmonary vascular remodeling in PAH rats induced by monocrotaline (MCT) treatment. Hemodynamic parameters were assessed using echocardiography and right ventricular catheterization. Right ventricular hypertrophy index analysis and hematoxylin and eosin staining were used to evaluate the degree of pulmonary vascular and right heart remodeling. Moreover, PKM2, p­PKM2, ERK, p­ERK, glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA) protein expression levels were semi­quantified using western blotting. The expression and distribution of PKM2 were assessed using immunofluorescence microscopy. The present study demonstrated that MCT treatment caused pulmonary arterial hypertension and pulmonary vascular remodeling in experimental rats. Shikonin improved hemodynamics and pulmonary vascular remodeling in MCT­induced PAH rats, decreased aerobic glycolysis and downregulated PKM2, p­PKM2, p­ERK, GLUT 1 and LDHA protein expression levels. Shikonin improved experimental pulmonary arterial hypertension hemodynamics and pulmonary vascular remodeling at least partly through the inhibition of PKM2 and the resultant suppression of aerobic glycolysis. These results provide a novel understanding of possible new treatment targets for PAH.

Curcumol suppresses endothelial-to-mesenchymal transition via inhibiting the AKT/GSK3ß signaling pathway and alleviates pulmonary arterial hypertension in rats.

Endothelial dysfunction is essential in pulmonary arterial hypertension (PAH) pathogenesis and is considered to be a therapeutic target of PAH. Curcumol is a bioactive sesquiterpenoid with pharmacological properties including restoring endothelial cells damage. This study aimed to evaluate the effect of curcumol on PAH rats and investigate its possible mechanisms. PAH was induced by subcutaneous injection of 60 mg/kg monocrotaline (MCT) in male Sprague Dawley rats. Curcumol (12.5, 25, and 50 mg/kg/day) were administered by intragastric administration for 3 weeks. The results demonstrated that curcumol dose-dependently alleviated MCT-induced right ventricular hypertrophy and pulmonary arterial wall thickness. In addition, endothelial-to-mesenchymal transition (EndMT) in the pulmonary arteries of MCT-challenged rats was inhibited after curcumol treatment, as evidenced by the restored expressions of endothelial and myofibroblast markers. The possible pharmacological mechanisms of curcumol were analyzed using network pharmacology. After screening the common therapeutic targets of PAH and curcumol by searching related databases and comparison, pathway enrichment was performed and AKT/GSK3ß was screened out as a possible signaling pathway which was relevant to the therapeutic mechanism of curcumol on PAH. Western blot analysis verified this in lung tissues. Moreover, combination of TNF-α, TGF-ß1 and IL-1ß-induced EndMT in primary rat pulmonary arterial endothelial cells were blocked by curcumol, and this effect was resembled by PI3K/AKT inhibitor LY294002. Above all, our study suggested that curcumol inhibited EndMT via inhibiting the AKT/GSK3ß signaling pathway, which may contribute to its alleviated effect on PAH. Curcumol may be developed as a therapeutic for PAH in the future.