Primary pulmonary hypertension

Therapeutic Potential of Treprostinil Inhalation Powder for Patients with Pulmonary Arterial Hypertension: Evidence to Date

Pulmonary arterial hypertension (PAH) is a complex and incurable disease for which pulmonary vasodilators remain the core therapy. Of the three primary pathways that vasodilators target, the prostacyclin pathway was the earliest to be used and currently has the largest number of modalities for drug delivery. Inhaled treprostinil has been introduced as a treatment option in PAH and, more recently, pulmonary hypertension (PH) due to interstitial lung disease (PH-ILD), and the earlier nebulized form has been joined by a dry powder form allowing for more convenient use. In this review, we discuss inhaled treprostinil, focusing on the dry powder inhalation (DPI) formulation, and explore its dosing, applications, and evidence to support patient tolerance and acceptance. Recent trials underpinning the evidence for use of inhaled treprostinil and the most recent developments concerning the drug are discussed. Finally, the review looks briefly into premarket formulations of inhaled treprostinil and relevant early studies suggesting efficacy in PAH treatment.

Population pharmacokinetic modeling of sotatercept in healthy participants and patients with pulmonary arterial hypertension

Sotatercept is a breakthrough, first-in-class biologic, that is FDA-approved for the treatment of pulmonary arterial hypertension (PAH). A population pharmacokinetic (PopPK) model was developed using data from two phase 1 studies in healthy participants, and two phase 2 studies and one phase 3 study in participants with PAH. The pooled sotatercept PK data encompassed single intravenous (IV) or subcutaneous (SC) doses ranging from 0.01 to 3.0 mg/kg, as well as multiple SC doses ranging from 0.03 to 1.0 mg/kg, with PK samples collected up to a maximum of ~150 weeks following Q3W and Q4W dosing regimens. The final PopPK analysis included 350 participants, with 30 and 320 participants receiving sotatercept IV and SC, respectively. A two-compartment model with a first-order absorption rate constant and a linear disposition from central compartment well-described sotatercept PK. The estimated bioavailability is ~66%; bioavailability, clearance (CL), and central volume (VC) have low to moderate inter-individual variability. Time-varying body weight and baseline albumin concentration were statistically significant predictors of PK; CL and VC were predicted to increase with increasing body weight, while CL was predicted to decrease with increasing baseline albumin concentration. However, the magnitude of covariate effects is not predicted to meaningfully alter the disposition of sotatercept. Altogether, the PopPK modeling results demonstrate favorable PK characteristics (low to moderate variability and typical bioavailability), supporting sotatercept as a SC biological agent for the treatment of patients with PAH.

Single cell transcriptomic analyses reveal diverse and dynamic changes of distinct populations of lung interstitial macrophages in hypoxia-induced pulmonary hypertension

Introduction

Hypoxia is a common pathological driver contributing to various forms of pulmonary vascular diseases leading to pulmonary hypertension (PH). Pulmonary interstitial macrophages (IMs) play pivotal roles in immune and vascular dysfunction, leading to inflammation, abnormal remodeling, and fibrosis in PH. However, IMs' response to hypoxia and their role in PH progression remain largely unknown. We utilized a murine model of hypoxia-induced PH to investigate the repertoire and functional profiles of IMs in response to acute and prolonged hypoxia, aiming to elucidate their contributions to PH development.

Methods

We conducted single-cell transcriptomic analyses to characterize the repertoire and functional profiles of murine pulmonary IMs following exposure to hypobaric hypoxia for varying durations (0, 1, 3, 7, and 21 days). Hallmark pathways from the mouse Molecular Signatures Database were utilized to characterize the molecular function of the IM subpopulation in response to hypoxia.

Results

Our analysis revealed an early acute inflammatory phase during acute hypoxia exposure (Days 1-3), which was resolved by Day 7, followed by a pro-remodeling phase during prolonged hypoxia (Days 7-21). These phases were marked by distinct subpopulations of IMs: MHCIIhiCCR2+EAR2+ cells characterized the acute inflammatory phase, while TLF+VCAM1hi cells dominated the pro-remodeling phase. The acute inflammatory phase exhibited enrichment in interferon-gamma, IL-2, and IL-6 pathways, while the pro-remodeling phase showed dysregulated chemokine production, hemoglobin clearance, and tissue repair profiles, along with activation of distinct complement pathways.

Discussion

Our findings demonstrate the existence of distinct populations of pulmonary interstitial macrophages corresponding to acute and prolonged hypoxia exposure, pivotal in regulating the inflammatory and remodeling phases of PH pathogenesis. This understanding offers potential avenues for targeted interventions, tailored to specific populations and distinct phases of the disease. Moreover, further identification of triggers for pro-remodeling IMs holds promise in unveiling novel therapeutic strategies for pulmonary hypertension.

Advancements in preclinical human-relevant modeling of pulmonary vasculature on-chip

Preclinical human-relevant modeling of organ-specific vasculature offers a unique opportunity to recreate pathophysiological intercellular, tissue-tissue, and cell-matrix interactions for a broad range of applications. Lung vasculature is particularly important due to its involvement in genesis and progression of rare, debilitating disorders as well as common chronic pathologies. Here, we provide an overview of the latest advances in the development of pulmonary vascular (PV) models using emerging microfluidic tissue engineering technology Organs-on-Chips (so-called PV-Chips). We first review the currently reported PV-Chip systems and their key features, and then critically discuss their major limitations in reproducing in vivo-seen and disease-relevant cellularity, localization, and microstructure. We conclude by presenting latest efforts to overcome such technical and biological limitations and future directions.

Efficacy of Sildenafil on healthy humans in high‑altitude hypoxia at rest and during exercise: A meta‑analysis

The current meta-analysis aimed to fully evaluate the efficacy of Sildenafil in healthy humans at different altitudes, focusing on echocardiographic and hemodynamic parameters. Relevant studies were retrieved from the Cochrane, Embase and PubMed databases. Odds ratios (OR) were determined for dichotomous data and weighted mean differences with 95% confidence intervals (CIs) for continuous data. A total of 16 RCTs were included in the current meta-analysis. Short-term treatment with Sildenafil significantly elevated resting heart rate (P<0.01) at altitudes <4,000 meters. No significant differences in heart rate were observed between the Sildenafil and placebo groups at rest and during exercise at an altitude of >4,000 meters (P>0.05). Sildenafil improved resting cardiac output at an altitude of >5,000 meters (P<0.01) and exercising arterial oxygen saturation at <4,000 meters (P<0.01). Sildenafil reduced resting pulmonary artery systolic pressure (PASP) at altitudes >4,000 meters (P<0.01) and exercising PASP at altitudes >5,000 meters (P<0.01). Therefore, Sildenafil efficacy in healthy humans with high-altitude hypoxia is related to altitude and rest or exercise.

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.

Medicinal and mechanistic overview of artemisinin in the treatment of human diseases

Artemisinin (ART) is a bioactive compound isolated from the plant Artemisia annua and has been traditionally used to treat conditions such as malaria, cancer, viral infections, bacterial infections, and some cardiovascular diseases, especially in Asia, North America, Europe and other parts of the world. This comprehensive review aims to update the biomedical potential of ART and its derivatives for treating human diseases highlighting its pharmacokinetic and pharmacological properties based on the results of experimental pharmacological studies in vitro and in vivo. Cellular and molecular mechanisms of action, tested doses and toxic effects of artemisinin were also described. The analysis of data based on an up-to-date literature search showed that ART and its derivatives display anticancer effects along with a wide range of pharmacological activities such as antibacterial, antiviral, antimalarial, antioxidant and cardioprotective effects. These compounds have great potential for discovering new drugs used as adjunctive therapies in cancer and various other diseases. Detailed translational and experimental studies are however needed to fully understand the pharmacological effects of these compounds.

Single Nucleotide Polymorphism rs9277336 Controls the Nuclear Alpha Actinin 4-Human Leukocyte Antigen-DPA1 Axis and Pulmonary Endothelial Pathophenotypes in Pulmonary Arterial Hypertension

Background Pulmonary arterial hypertension (PAH) is a complex, fatal disease where disease severity has been associated with the single nucleotide polymorphism (SNP) rs2856830, located near the human leukocyte antigen DPA1 (HLA-DPA1) gene. We aimed to define the genetic architecture of functional variants associated with PAH disease severity by identifying allele-specific binding transcription factors and downstream targets that control endothelial pathophenotypes and PAH. Methods and Results Electrophoretic mobility shift assays of oligonucleotides containing SNP rs2856830 and 8 SNPs in linkage disequilibrium revealed functional SNPs via allele-imbalanced binding to human pulmonary arterial endothelial cell nuclear proteins. DNA pulldown proteomics identified SNP-binding proteins. SNP genotyping and clinical correlation analysis were performed in 84 patients with PAH at University of Pittsburgh Medical Center and in 679 patients with PAH in the All of Us database. SNP rs9277336 was identified as a functional SNP in linkage disequilibrium (r2>0.8) defined by rs2856830, and the minor allele was associated with decreased hospitalizations and improved cardiac output in patients with PAH, an index of disease severity. SNP pulldown proteomics showed allele-specific binding of nuclear ACTN4 (alpha actinin 4) protein to rs9277336 minor allele. Both ACTN4 and HLA-DPA1 were downregulated in pulmonary endothelium in human patients and rodent models of PAH. Via transcriptomic and phenotypic analyses, knockdown of HLA-DPA1 phenocopied knockdown of ACTN4, both similarly controlling cell structure pathways, immune pathways, and endothelial dysfunction. Conclusions We defined the pathogenic activity of functional SNP rs9277336, entailing the allele-specific binding of ACTN4 and controlling expression of the neighboring HLA-DPA1 gene. Through inflammatory or genetic means, downregulation of this ACTN4-HLA-DPA1 regulatory axis promotes endothelial pathophenotypes, providing a mechanistic explanation for the association between this SNP and PAH outcomes.

Jaggeds/Notches promote endothelial-mesenchymal transition-mediated pulmonary arterial hypertension via upregulation of the expression of GATAs

This study tested the hypothesis that Jagged2/Notches promoted the endothelial-mesenchymal transition (endMT)-mediated pulmonary arterial hypertension (PAH) (i.e. induction by monocrotaline [MCT]/63 mg/kg/subcutaneous injection) through increasing the expression of GATA-binding factors which were inhibited by propylthiouracil (PTU) (i.e. 0.1% in water for daily drinking since Day 5 after PAH induction) in rodent. As compared with the control (i.e. HUVECs), the protein expressions of GATAs (3/4/6) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly reduced, whereas the endothelial-phenotype markers (CD31/E-cadherin) were significantly increased in silenced JAG2 gene or in silenced GATA3 gene of HUVECs (all p < 0.001). As compared with the control, the protein expressions of intercellular signallings (GATAs [3/4/6], Jagged1/2, notch1/2 and Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly upregulated in TGF-ß/monocrotaline-treated HUVECs that were significantly reversed by PTU treatment (all p < 0.001). By Day 42, the results of animal study demonstrated that the right-ventricular systolic-blood-pressure (RVSBP), RV weight (RVW) and lung injury/fibrotic scores were significantly increased in MCT group than sham-control (SC) that were reversed in MCT + PTU groups, whereas arterial oxygen saturation (%) and vasorelaxation/nitric oxide production of PA exhibited an opposite pattern of RVW among the groups (all p < 0.0001). The protein expressions of hypertrophic (ß-MHC)/pressure-overload (BNP)/oxidative-stress (NOX-1/NOX-2) biomarkers in RV and the protein expressions of intercellular signalling (GATAs3/4/6, Jagged1/2, notch1/2) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/TGF-ß/α-SMA/p-Smad2) in lung parenchyma displayed an identical pattern of RVW among the groups (all p < 0.0001). Jagged-Notch-GATAs signalling, endMT markers and RVSBP that were increased in PAH were suppressed by PTU.

The ratio of TAPSE to PASP predicts prognosis in lung transplant candidates with pulmonary arterial hypertension

Lung transplantation (LT) is the only option for patients with pulmonary arterial hypertension (PAH) refractory to maximal medical therapy. However, some patients referred for LT could survive without LT, and its determinants remain unclear. This study aimed to elucidate prognostic factors of severe PAH at the referral time. We retrospectively analyzed 34 patients referred for LT evaluation. The primary outcome was a composite of death or LT. Over a median follow-up period of 2.56 years, eight patients received LT and eight died. Compared with LT-free survival group, pulmonary arterial systolic pressure (PASP) was higher (p = 0.042), and the ratio of tricuspid annular plane systolic excursion (TAPSE) to PASP (TAPSE/PASP) was lower (p = 0.01) in LT or death group. In receiver operating characteristic analysis, the area under the curve was 0.759 (95% confidence interval 0.589-0.929) for TAPSE/PASP to predict primary outcome, and the optimal cut-off value was 0.30 mm/mmHg (sensitivity 0.875 and specificity 0.667). In a multivariate analysis, TAPSE/PASP was independently associated with death or LT. Kaplan-Meier analysis showed a better LT-free survival in patients with TAPSE/PASP ≧0.30 mm/mmHg than in those with < 0.30 mm/mmHg (p = 0.001). Low-level TAPSE/PASP could be a poor prognostic factor in PAH patients referred for LT evaluation.

Effect of Phosphodiesterase-5 (PDE-5) Inhibitors on Clinical Outcomes in Patients With Pulmonary Hypertension: A Meta-Analysis of Randomized Control Trials

We intended to summarize the most recent research pertaining to the use of phosphodiesterase-5 (PDE5) inhibitors in pulmonary hypertension in light of recent developments in the knowledge of the pathophysiological mechanisms and treatments for pulmonary hypertension, with major contributions in the area in the last decade. The aim of this meta-analysis is to determine the efficacy of PDE5 inhibitors for pulmonary hypertension in adults. We followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines to carry out this meta-analysis. Online database searching to identify eligible trials was performed in MEDLINE, EMBASE, and the Cochrane Library by two authors independently. Outcomes assessed in the current meta-analysis included change in the cardiac index from baseline in liters per minute per square meter (L/min/m²), mean peripheral arterial pressure (PAP) in mm Hg, mortality, hospitalization, and six-minute walking distance (6MWD) in meters (m). Overall, 17 articles met the inclusion criteria and were included in the current meta-analysis. PDE5 inhibitors significantly improve cardiac index (mean difference: 0.18, 95% CI: 0.04, 0.32, p-value: 0.01), mean PAP (mean difference: -5.61, 95% CI: -7.60, -3.62, p-value: 0.01), and 6MWD (mean difference: 26.26, 95% CI: 16.95, 35.57, p-value: 0.001) as compared to the patients in the control group. No significant difference was found in terms of risk of mortality (risk ratio (RR): 0.51, 95% CI: 0.17, 1.54) and risk of hospitalization (RR: 0.59, 95% CI: 0.23, 1.55) between the two groups. The current meta-analysis concluded that PDE5 inhibitors improve 6MWD, mean PAP, and cardiac index in patients with pulmonary hypertension. However, no significant difference was reported in terms of mortality and hospitalization between the two groups.

Obstructive sleep apnea-increased DEC1 regulates systemic inflammation and oxidative stress that promotes development of pulmonary arterial hypertension

Obstructive sleep apnea (OSA), characterized by chronic intermittent hypoxia (CIH), is a common risk factor for pulmonary arterial hypertension (PAH). As a hypoxia-induced transcription factor, differentially expressed in chondrocytes (DEC1) negatively regulates the transcription of peroxisome proliferative activated receptor-γ (PPARγ), a recognized protective factor of PAH. However, whether and how DEC1 is associated with PAH pathogenesis remains unclear. In the present study, we found that DEC1 was increased in lungs and pulmonary arterial smooth muscle cells (PASMCs) of rat models of OSA-associated PAH. Oxidative indicators and inflammatory cytokines were also elevated in the blood of the rats. Similarly, hypoxia-treated PASMCs displayed enhanced DEC1 expression and reduced PPARγ expression in vitro. Functionally, DEC1 overexpression exacerbated reactive oxygen species (ROS) production and the expression of pro-inflammatory cytokines (such as TNFα, IL-1β, IL-6, and MCP-1) in PASMCs. Conversely, shRNA knockdown of Dec1 increased PPARγ expression but attenuated hypoxia-induced oxidative stress and inflammatory responses in PASMCs. Additionally, DEC1 overexpression promoted PASMC proliferation, which was drastically attenuated by a PPARγ agonist rosiglitazone. Collectively, these results suggest that hypoxia-induced DEC1 inhibits PPARγ, and that this is a predominant mechanism underpinning oxidative stress and inflammatory responses in PASMCs during PAH. DEC1 could be used as a potential target to treat PAH.

Drug Interactions Associated With Therapies for Pulmonary Arterial Hypertension

Objective: To evaluate the potential for drug interactions with therapies for pulmonary arterial hypertension (PAH). Treatments include calcium channel blockers, phosphodiesterase type 5 inhibitors, endothelin receptor antagonists, guanylate cyclase stimulators, prostacyclin analogues, and prostacyclin receptor agonists. Data Sources: A systemic literature search (January 1980-December 2021) was performed using PubMed and EBSCO to locate relevant articles. The mesh terms used included each specific medication available as well as "drug interactions." DAILYMED was used for product-specific drug interactions. Study Selection and Data Extraction: The search was conducted to identify drug interactions with PAH treatments. The search was limited to those articles studying human applications with PAH treatments and publications using the English language. Case reports, clinical trials, review articles, treatment guidelines, and package labeling were selected for inclusion. Data Synthesis: Primary literature and package labeling indicate that PAH treatments are subject to pharmacokinetic and pharmacodynamic interactions. The management of PAH is rapidly evolving. As more and more evidence becomes available for the use of combination therapy in PAH, the increasing use of combination therapy increases the risk of drug-drug interactions. Pulmonary arterial hypertension is also associated with other comorbidities that require concomitant pharmacotherapy. Conclusion: The available literature indicates that PAH therapies are associated with clinically significant drug interactions and the potential for subsequent adverse reactions. Clinicians in all practice settings should be mindful that increased awareness of drug interactions with PAH therapy will ensure optimal management and patient safety.

Methylation-mediated silencing of PTPRD induces pulmonary hypertension by promoting pulmonary arterial smooth muscle cell migration via the PDGFRB/PLCγ1 axis

OBJECTIVE

Pulmonary hypertension is a lethal disease characterized by pulmonary vascular remodeling and is mediated by abnormal proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). Platelet-derived growth factor BB (PDGF-BB) is the most potent mitogen for PASMCs and is involved in vascular remodeling in pulmonary hypertension development. Therefore, the objective of our study is to identify novel mechanisms underlying vascular remodeling in pulmonary hypertension.

METHODS

We explored the effects and mechanisms of PTPRD downregulation in PASMCs and PTPRD knockdown rats in pulmonary hypertension induced by hypoxia.

RESULTS

We demonstrated that PTPRD is dramatically downregulated in PDGF-BB-treated PASMCs, pulmonary arteries from pulmonary hypertension rats, and blood and pulmonary arteries from lung specimens of patients with hypoxic pulmonary arterial hypertension (HPAH) and idiopathic PAH (iPAH). Subsequently, we found that PTPRD was downregulated by promoter methylation via DNMT1. Moreover, we found that PTPRD knockdown altered cell morphology and migration in PASMCs via modulating focal adhesion and cell cytoskeleton. We have demonstrated that the increase in cell migration is mediated by the PDGFRB/PLCγ1 pathway. Furthermore, under hypoxic condition, we observed significant pulmonary arterial remodeling and exacerbation of pulmonary hypertension in heterozygous PTPRD knock-out rats compared with the wild-type group. We also demonstrated that HET group treated with chronic hypoxia have higher expression and activity of PLCγ1 in the pulmonary arteries compared with wild-type group.

CONCLUSION

We propose that PTPRD likely plays an important role in the process of pulmonary vascular remodeling and development of pulmonary hypertension in vivo .

Role of solid lipid nanoparticle for the delivery of Lipophilic Drugs and Herbal Medicines in the treatment of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is an uncommon condition marked by elevated pulmonary artery pressure that leads to right ventricular failure. The majority of drugs are now been approved by FDA for PAH, however, several biopharmaceutical hindrances lead to failure of the therapy. Various novel drug delivery systems are available in the literature from which lipid-based nanoparticles i.e. solid lipid nanoparticle is widely investigated for improving the solubility and bioavailability of drugs. In this paper, the prototype phytoconstituents used in pulmonary arterial hypertension have limited solubility and bioavailability. We highlighted the novel concepts of SLN for lipophilic phytoconstituents with their potential applications. This paper also reviews the present state of the art regarding production techniques for SLN like High-Pressure Homogenization, Micro-emulsion Technique, and Phase Inversion Temperature Method, etc. Furthermore, toxicity aspects and in vivo fate of SLN are also highlighted in this review. In a nutshell, safer delivery of phytoconstituents by SLN added a novel feather to the cap of successful drug delivery technologies.

Potential of the TRPM7 channel as a novel therapeutic target for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.

Hotspots and frontiers in pulmonary arterial hypertension research: a bibliometric and visualization analysis from 2011 to 2020

Pulmonary arterial hypertension (PAH) is a group of devastating and progressive disorders, resulting in relentless increases in pulmonary vascular resistance. The number of studies related to PAH has been increasing in recent years. Our study aims to illustrate trends in PAH research over the past decade using bibliometric analysis. Science Citation Index-Expanded was adopted to search studies concerning PAH between 2011 and 2020. The bibliographic information was converted and analyzed automatically using a bibliometric package in R software and citespace. The annual quantity of publications on PAH showed an overall increase last decade. The United States was the most prolific country with 2,479 publications, and it was also the country that cooperated most with other countries. Hôpital Bicêtre made important research achievements on PAH and was a leader in study cooperation. Marc Humbert led the PAH field by publishing 150 articles in the past decade. During the past decade, there was a close transnational relation among countries or regions, institutions and authors. Further, Circulation was the most cited journal, followed by the Journal of the American College of Cardiology and the American Journal of Respiratory and Critical Care Medicine, with 3,895, 3,406, and 3,170 citations, respectively. The global research status and trend of PAH are deeply understood for the first time using bibliometric and visual methods, and the results of our study bring us a valuable reference for clinical researchers.

This is the first study to illustrate trends in pulmonary arterial hypertension research using bibliometric analysis.

Our study provides extensive and in-depth directions for researchers.

Our study may benefit further researches on the etiology, diagnosis, and treatment of pulmonary arterial hypertension.

The Glycobiology of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease of complex etiology. Cases of PAH that do not receive therapy after diagnosis have a low survival rate. Multiple reports have shown that idiopathic PAH, or IPAH, is associated with metabolic dysregulation including altered bioavailability of nitric oxide (NO) and dysregulated glucose metabolism. Multiple processes such as increased proliferation of pulmonary vascular cells, angiogenesis, apoptotic resistance, and vasoconstriction may be regulated by the metabolic changes demonstrated in PAH. Recent reports have underscored similarities between metabolic abnormalities in cancer and IPAH. In particular, increased glucose uptake and altered glucose utilization have been documented and have been linked to the aforementioned processes. We were the first to report a link between altered glucose metabolism and changes in glycosylation. Subsequent reports have highlighted similar findings, including a potential role for altered metabolism and aberrant glycosylation in IPAH pathogenesis. This review will detail research findings that demonstrate metabolic dysregulation in PAH with an emphasis on glycobiology. Furthermore, this report will illustrate the similarities in the pathobiology of PAH and cancer and highlight the novel findings that researchers have explored in the field.

BREEZE: Open‐label Clinical Study to Evaluate the Safety and Tolerability of Treprostinil Inhalation Powder as Tyvaso DPI™ in Patients With Pulmonary Arterial Hypertension

Inhaled treprostinil is an approved therapy for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease in the United States. Studies have confirmed the robust benefits and safety of nebulized inhaled treprostinil, but it requires a time investment for nebulizer preparation, maintenance, and treatment. A small, portable treprostinil dry powder inhaler has been developed for the treatment of PAH. The primary objective of this study was to evaluate the safety and tolerability of treprostinil inhalation powder (TreT) in patients currently treated with treprostinil inhalation solution. Fifty‐one patients on a stable dose of treprostinil inhalation solution enrolled and transitioned to TreT at a corresponding dose. Six‐minute walk distance (6MWD), device preference and satisfaction (Preference Questionnaire for Inhaled Treprostinil Devices [PQ‐ITD]), PAH Symptoms and Impact (PAH‐SYMPACT®) questionnaire, and systemic exposure and pharmacokinetics for up to 5 h were assessed at baseline for treprostinil inhalation solution and at Week 3 for TreT. Adverse events (AEs) were consistent with studies of inhaled treprostinil in patients with PAH, and there were no study drug‐related serious AEs. Statistically significant improvements occurred in 6MWD, PQ‐ITD, and PAH‐SYMPACT. Forty‐nine patients completed the 3‐week treatment phase and all elected to participate in an optional extension phase. These results demonstrate that, in patients with PAH, transition from treprostinil inhalation solution to TreT is safe, well‐tolerated, and accompanied by statistically significant improvements in key clinical assessments and patient‐reported outcomes with comparable systemic exposure between the two formulations at evaluated doses (trial registration: clinicaltrials.gov identifier: NCT03950739).

A literature review on pulmonary arterial hypertension (PAH)

Background:

PAH was first of all reported from German Doctor E. Romberg in 1891, It's usually found throughout the globe, but it is a burden in India and other developing countries. Pulmonary arterial hypertension (PAH) is characterized by a rise in pulmonary arterial pressure and the development of progressive symptoms like reduction in functional ability, shortness of breath and fatigue. The pulmonary arteries move blood from the right side of the heart over the lungs.

Introduction:

Increase pressure in pulmonary arteries known as pulmonary arterial pressure (PAH). The treatment of is require because without it, the right heart to work much harder due to high blood pressure in the lungs, and over time it became reason of heart failure. In this article, we have tried to provide brief information about the prevalence, pathology, classification and different therapies of PAH. Combining medicines from different categories is currently given as quality care and has been revealed to boost outcomes. A small part of the new treatment options has been included.

Evaluation of herb-drug interaction of ambrisentan with shikonin based on UPLC-MS/MS

CONTEXT

Ambrisentan is an oral endothelin-receptor antagonist (ERA). However, there is no report on the interaction between ambrisentan and shikonin.

OBJECTIVE

To investigate the effect of shikonin on ambrisentan metabolism in vivo and in vitro.

MATERIALS AND METHODS

This study developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ambrisentan and (S)-4-hydroxymethyl ambrisentan in rat plasma. Twelve male Sprague-Dawley (SD) rats were divided into two groups (n = 6): the control group and shikonin (20 mg/kg) group. The pharmacokinetics of ambrisentan (2.5 mg/kg) were investigated after 30 min. Additionally, human and rat liver microsomes were used to investigate the herb-drug interaction.

RESULTS

The UPLC-MS/MS method was shown to be accurate, precise and reliable, and was successfully applied to the herb-drug interaction study of ambrisentan with shikonin. When co-administrated with 20 mg/kg shikonin, the C_max and AUC_(0-∞) of ambrisentan were significantly increased by 44.96 and 16.65%, respectively (p < 0.05). In addition, there were modest decreases in (S)-4-hydroxymethyl ambrisentan C_max and AUC_(0-∞) in the presence of shikonin (p < 0.05), which indicated that these results were in accordance with the inhibition of shikonin on ambrisentan metabolism. Moreover, enzyme kinetic study indicated that shikonin had an inhibitory effect on human and rat microsomes where the IC₅₀ values of shikonin were 5.865 and 6.358 μM, respectively.

CONCLUSIONS

Our study indicated that shikonin could inhibit ambrisentan metabolism. Further studies need to be carried out to verify whether similar interaction truly apply in humans and whether this interaction has clinical significance.

Risk factors of pulmonary arterial hypertension in patients with systemic lupus erythematosus

OBJECTIVES

Pulmonary arterial hypertension symptoms in systemic lupus erythematosus patients are non-specific and early diagnosis and intervention are challenging. It remains essential to explore risk factors for pulmonary arterial hypertension in systemic lupus erythematosus patients to identify high risk patients and allow intensive monitoring.

METHODS

From January 2010 to December 2018, 84 patients with systemic lupus erythematosus and pulmonary arterial hypertension and 160 patients with systemic lupus erythematosus but without pulmonary arterial hypertension were enrolled. Clinical manifestations and laboratory test results were compared between the two groups to identify predictors of pulmonary arterial hypertension. Candidate pulmonary arterial hypertension risk factors were further compared among systemic lupus erythematosus-pulmonary arterial hypertension patients with different characteristics.

RESULTS

Among collected patient characteristics, Raynaud's phenomenon (OR 2.32, 95% CI: 1.17-4.61), digital vasculitis (OR 4.12, 95% CI: 1.48-11.49), pericardial effusion, pulmonary interstitial lesions, positive anti-u1 ribonucleoprotein antibodies, and positive anticardiolipin antibodies immunoglobulin G were associated with significantly higher risk of pulmonary arterial hypertension in systemic lupus erythematosus patients. Among these candidate risk factors, positive anti-u1 ribonucleoprotein antibody was independently associated with severe pulmonary arterial hypertension and more active disease. Digital vasculitis was independently associated with systemic lupus erythematosus alleviation, while pericardial effusion was associated with systemic lupus erythematosus deterioration. Pericardial effusion was associated with longer pulmonary arterial hypertension duration.

CONCLUSION

The significant association between studied clinical and laboratory indicators and risk of pulmonary arterial hypertension, pulmonary arterial hypertension and systemic lupus erythematosus characteristics suggested that these factors can be used to identify patients at higher risk of pulmonary arterial hypertension and adverse outcomes. Close monitoring may be indicated in patients with these risk factors, especially with more than one risk factor.

Ubiquinol ameliorates endothelial dysfunction and increases expression of miRNA-34a in a rat model of pulmonary hypertension

Introduction: In this research, we evaluate the effect of intravenously administrated solubilized ubiquinol on 4-week monocrotalin-induced pulmonary hypertension (PH) in rats.

Materials and methods: To reproduce the model, some male Wistar rats were subcutaneously injected with alcohol solution of monocrotaline 60 mg/kg and the rest – with alcohol solution (Control). Those with monocrotaline (MCT) were divided into 3 groups. They underwent intravenous administration of 1% ubiquinol solution 30 mg/kg (MCT-Ubiquinol), the vehicle (MCT-Vehicle) and saline (MCT-saline) three times on days 7, 14 and 21, depending on the group. The hemodynamic parameters were measured in anesthetized rats on day 29. Right ventricle hypertrophy, pulmonary arteries reactivity and expression of miRNA-21 and miRNA-34a were estimated after euthanasia.

Results and discussion: All MCT-groups demonstrated an increase in right ventricle systolic pressure and hypertrophy in comparison with the control group. An increase in lung weight was shown in MCT-Vehicle and MCT-Saline; however, the MCT-Ubiquinol indicators did not differ from those of the Control. There was an increased vasodilatation response to acetylcholine at concentrations of 1*10-6M and 1*10-5M in MCT-Ubiquinol in contrast to the other two MCT-groups. A significantly lower level of expression of miRNA-34a was observed in MCT-Ubiquinol.

Conclusion: Our findings suggest that a triple ubiquinol injection influences pulmonary changes and endothelium-depended vasodilatation, which contributes to pulmonary vascular tone and reactivity. A decrease in miRNA-34a expression in MCT-Ubiquinol group demonstrates the ubiquinol anti-inflammatory properties.

Cardiovascular Effects Mediated by HMMR and CD44

Cardiovascular disease (CVD) is the leading cause of death worldwide. The most dangerous life-threatening symptoms of CVD are myocardial infarction and stroke. The causes of CVD are not entirely clear, and new therapeutic targets are still being sought. One of the factors involved in CVD development among vascular damage and oxidative stress is chronic inflammation. It is known that hyaluronic acid plays an important role in inflammation and is regulated by numerous stimuli, including proinflammatory cytokines. The main receptors for hyaluronic acid are CD44 and RHAMM. These receptors are membrane proteins that differ in structure, but it seems that they can perform similar or synergistic functions in many diseases. Both RHAMM and CD44 are involved in cell migration and wound healing. However, their close association with CVD is not fully understood. In this review, we describe the role of both receptors in CVD.

Substantial involvement of TRPM7 inhibition in the therapeutic effect of Ophiocordyceps sinensis on pulmonary hypertension

Ophiocordyceps sinensis (OCS), an entomopathogenic fungus, is known to exert antiproliferative and antitissue remodeling effects. Vascular remodeling and vasoconstriction play critical roles in the development of pulmonary hypertension (PH). The therapeutic potential of OCS for PH was investigated using rodent PH models, and cultured pulmonary artery endothelial and smooth muscle cells (PAECs and PASMCs), with a focus on the involvement of TRPM7. OCS ameliorated the development of PH, right ventricular hypertrophy and dysfunction in the monocrotaline-induced PH rats. The genetic knockout of TRPM7 attenuated the development of PH in mice with monocrotaline pyrrole-induced PH. TRPM7 was associated with medial hypertrophy and the plexiform lesions in rats and humans with PH. OCS suppressed proliferation of PASMCs derived from the PH patients. Ethanol extracts of OCS inhibited TRPM7-like current, TGF-β2-induced endothelial-mesenchymal transition, IL-6-induced STAT3 phosphorylation, and PDGF-induced Akt phosphorylation in PAECs or PASMCs. These inhibitory effects were recapitulated by either siRNA-mediated TRPM7 knockdown or treatment with TRPM7 antagonist FTY-720. OCS and FTY-720 induced vasorelaxation in the isolated normal human pulmonary artery. As a result, the present study proposes the therapeutic potential of OCS for the treatment of PH. The inhibition of TRPM7 is suggested to underlie the therapeutic effect of OCS.

Dihydroartemisinin Attenuates Pulmonary Hypertension Through Inhibition of Pulmonary Vascular Remodeling in Rats

Pulmonary arterial hypertension (PAH) is a malignant disease characterized by pulmonary arterial remodeling because of the abnormal proliferation and migration of pulmonary arterial smooth muscle cells. Dihydroartemisinin (DHA), an artemisinin derivative used to treat malaria, is able to inhibit fibrosis, neovascularization, and tumor proliferation. In this study, we hypothesized that DHA can be beneficial in treating PAH. To test this hypothesis, a rat model of pulmonary hypertension induced with monocrotaline (MCT) was used. Compared with MCT treatment alone, treatment with 50 or 100 mg/kg DHA significantly reduced the mean pulmonary arterial pressure (30.11 ± 2.48 mm Hg vs. 21.35 ± 3.04 mm Hg and 19.18 ± 1.98 mm Hg, respectively, both P < 0.01), right ventricular transverse diameter (4.36 ± 0.41 mm vs. 3.72 ± 0.24 mm and 3.67 ± 0.27 mm, respectively, both P < 0.01), pulmonary artery medial wall thickness (57.93 ± 11.14% vs. 34.45 ± 4.39% and 25.01 ± 6.66%, respectively, both P < 0.01), and increased tricuspid annular plane systolic excursion (1.34 ± 0.17 mm vs. 1.62 ± 0.3 mm and 1.62 ± 0.16 mm, respectively, both P < 0.05). We also found that DHA inhibited platelet-derived growth factor-BB-mediated pulmonary arterial smooth muscle cells proliferation and migration in a dose-dependent manner. Moreover, DHA downregulated β-catenin levels while upregulating the levels of axis inhibition protein 2 (Axin2) and glycogen synthase kinase 3β (GSK-3β). Our findings suggest that DHA, which may be a potential candidate for PAH therapy, attenuates experimental pulmonary hypertension possibly by inhibiting pulmonary vascular remodeling.

Development of A 3D-Printed Navigational Template for Establishing Rabbit VX2 Lung Cancer Model

BACKGROUND

The CT-guided percutaneous puncture-inoculation for establishing the rabbit VX2 lung cancer model (LCM) is time-consuming, requires repeated CT scans, and has a high complication rate. Therefore, this study aimed to develop a navigational template using 3D technology to provide an alternative method for establishing the model with improved success and complication rates.

MATERIALS AND METHODS

Ideal pressure was determined using chest CT data from 15 anesthetized rabbits fitted with sphygmomanometer cuff around their chests. Subsequently, a preliminary 3D template with a square window and cross-sign to facilitate precise installation was designed. Using another 20 rabbits fixed with the preliminary template, an ideal common puncture point and parameter were determined, a navigational tunnel was set up on the template surface, and the final puncture navigational template was printed out. Eight-four rabbits (42/group) were assigned to the experimental (template-guided puncture) and control (traditional puncutre) groups and underwent VX2 tumor-fragment inoculation to validate the template. Differences in various parameters between two groups were analyzed.

RESULTS

The ideal pressure was 30 mmHg. All rabbits were inoculated successfully and the template adequately fit the rabbit chest. The experimental group displayed significantly better operation time (198.93±36.64 vs 735.14±91.19 seconds); number of CT scans (0 vs 7.19±1.64); pneumothorax (11.9% vs 35.7%), chest seeding (16.7% vs 35.7%), and mid-lung field tumor-bearing (88.1% vs 59.5%) rates than the control group (all, P <0.05). The groups did not differ in rib injury, tumor volume or survival time (all, P > 0.05).

CONCLUSIONS

We successfully developed a puncture navigational template, providing an alternative method for establishing the rabbit VX2 LCM.

Cerebral large artery stenosis and occlusion in POEMS syndrome

BACKGROUND

This study aimed to investigate the frequency and risk factors for cerebral artery stenosis and occlusion in patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome.

METHODS

We reviewed results of magnetic resonance angiography (MRA) or computed tomography angiography (CTA) in 61 patients with POEMS syndrome seen between 2010 and 2017. Stenosis or occlusion was assessed in the initial MRA/CTA. Multivariate analysis was used to identify risk factors for artery stenosis/occlusion. In an autopsy case, pathologic examination was conducted of the occluded middle cerebral arteries.

RESULTS

Stenosis (> 50 %) or occlusion of the major cerebral arteries was found in 29 (47.5 %) patients on the initial MRA/CTA. The internal carotid artery was involved most frequently (32.8 %), followed by the anterior (21.3 %) and middle (16.4 %) cerebral arteries. The basilar (1.3 %) and vertebral (3.6 %) arteries were rarely affected. Cerebral infarction developed in eight (13.1 %) patients. The serum vascular endothelial growth factor (VEGF) level was an independent predictor for stenosis/occlusion (odds ratio, 1.228; 95 % confidence interval, 1.042-1.447; P = 0.014). An autopsy study showed occluded middle cerebral arteries by fibrous and myxomatous thickening of intima with splitting of the internal elastic lamina. Follow-up MRA in 23 patients showed improved, worsened, and unchanged stenosis in 20.7 %, 8.7 %, and 69.6 %, respectively.

CONCLUSIONS

Cerebral large-vessel stenosis or occlusion is frequently seen in approximately half of patients with POEMS syndrome. Vasculopathy was related to serum VEGF levels and thereby disease activity. Assessment of cerebral vessels is recommended in these patients to improve management.

Epoprostenol for the treatment of pulmonary arterial hypertension

Introduction: Pulmonary arterial hypertension (PAH) is a rare, progressive, and severe disease. Since the first demonstration of survival benefit of intravenous epoprostenol in monotherapy in 1996, prostanoids remain the cornerstone for PAH patients at high risk. This review is essential to understand the current situation of this drug among all the therapeutic possibilities concerning this entity.Areas covered: The aim of this article is to review the pharmacological properties of epoprostenol and to update its clinical evidence in different specific clinical scenarios. A deep literature search was carried out on the MEDLINE database for published literature before March 2021.Expert opinion: Epoprostenol is still the best treatment option for high-risk PAH patients. Nevertheless, there are many unsolved questions: drug dosing, its use in combination therapy with other pulmonary vasodilators, and the utility in PAH associated with connective tissue disease, congenital heart disease, or pulmonary veno-occlusive disease are only a few examples. Its safety and efficacy are supported by clinical trials, observational work, and experience, both as monotherapy and in combination therapy. Epoprostenol should be considered a destination treatment in high-risk patients and not only as a bridge to pulmonary transplantation. However, it remains underused in clinical practice.

The benefit of exercise-based rehabilitation programs in patients with pulmonary hypertension: a systematic review and meta-analysis of randomized controlled trials

Several studies have suggested that exercise capacity and quality of life are reduced in patients with pulmonary hypertension, and exercise-based rehabilitation can improve exercise capacity and quality of life in patients with pulmonary hypertension. The aim of this study is to assess the efficacy and safety of exercise-based rehabilitation in patients with pulmonary hypertension through a meta-analysis of randomized controlled trials. We searched PubMed, Embase, Medline, and the Cochrane Central Register of Controlled Trials up to November 2018. All randomized controlled trials comparing exercise capacity and quality of life between patients undergoing exercise-based rehabilitation and those undergoing non-exercise training were included. Data were extracted separately and independently by two investigators, and discrepancies were arbitrated by the third investigator. We used the random-effects model to analyze the results, the GRADE to assess the risk of bias in the included studies, and I² statistic to estimate the degree of heterogeneity. Nine randomized controlled trials are included; however, only seven randomized controlled trials were able to extract data. Including inpatients and outpatients, the total number of participants was 234, most of whom were diagnosed as pulmonary artery hypertension. The study duration ranged from 3 to 15 weeks. The mean six-minute walking distance after exercise training was 51.94 m higher than control (27.65-76.23 m, n = 234, 7 randomized controlled trials, low quality evidence), the mean peak oxygen uptake was 2.96 ml/kg/min higher (2.49-3.43 ml/kg/min, n = 179, 4 randomized controlled trials, low-quality evidence) than in the control group. In conclusion, our finding suggests that an exercise-based training program positively influences exercise capacity in patients with pulmonary hypertension.

Increased MAO-A Activity Promotes Progression of Pulmonary Arterial Hypertension

Monoamine oxidases (MAOs), a class of enzymes bound to the outer mitochondrial membrane, are important sources of reactive oxygen species. Increased MAO-A activity in endothelial cells and cardiomyocytes contributes to vascular dysfunction and progression of left heart failure. We hypothesized that inhibition of MAO-A can be used to treat pulmonary arterial hypertension (PAH) and right ventricular (RV) failure. MAO-A levels in lung and RV samples from patients with PAH were compared with levels in samples from donors without PAH. Experimental PAH was induced in male Sprague-Dawley rats by using Sugen 5416 and hypoxia (SuHx), and RV failure was induced in male Wistar rats by using pulmonary trunk banding (PTB). Animals were randomized to receive either saline or the MAO-A inhibitor clorgyline at 10 mg/kg. Echocardiography and RV catheterization were performed, and heart and lung tissues were collected for further analysis. We found increased MAO-A expression in the pulmonary vasculature of patients with PAH and in experimental experimental PAH induced by SuHx. Cardiac MAO-A expression and activity was increased in SuHx- and PTB-induced RV failure. Clorgyline treatment reduced RV afterload and pulmonary vascular remodeling in SuHx rats through reduced pulmonary vascular proliferation and oxidative stress. Moreover, clorgyline improved RV stiffness and relaxation and reversed RV hypertrophy in SuHx rats. In PTB rats, clorgyline had no direct clorgyline had no direct effect on the right ventricle effect. Our study reveals the role of MAO-A in the progression of PAH. Collectively, these findings indicated that MAO-A may be involved in pulmonary vascular remodeling and consecutive RV failure.

[Organ Bath Experiments on Human Pulmonary Vessels: Assessment of Drug Efficacy for Treatment of Pulmonary Arterial Hypertension]

Various vasodilator medications are used in the treatment of pulmonary arterial hypertension (PAH), such as endothelin receptor antagonists (ERA) or phosphodiesterase-5-(PDE-5-)inhibitors. In a human ex vivo model, we investigated whether the combination of two substance classes could achieve a higher effect or - without loss of vasodilatation - a lower dosage of the individual substances might be sufficient. We established an ex vivo organ bath model to evaluate the dose-dependent effects of ERA and PDE-5-inhibitors on pulmonary vessels harvested from patients who underwent surgery (lung resection/transplantation). We compared the combined use of both substance classes with administration of one class of drugs alone. Due to the limitations of the experimental design, it is not possible to extrapolate our results to the conditions in vivo. Nevertheless, organ bath proved to be helpful in evaluating the dose-dependent effects of ERA and PDE-5 inhibitors, which is not practical in everyday clinical practice. In this setting, the effectiveness of the combination therapy and the potential for dose reduction depended on the concentrations used and on the influence of previous illnesses on blood vessel function. This article describes the most important results of our experimental investigations and suggestions for future projects.

Inhaled bosentan microparticles for the treatment of monocrotaline-induced pulmonary arterial hypertension in rats

The conventional treatment of pulmonary arterial hypertension (PAH) with oral bosentan hydrate has limitations related to the lack of pulmonary selectivity. In this study, we verified the hypothesis of the feasibility of dry powder inhalation of bosentan as an alternative to oral bosentan hydrate for the treatment of PAH. Inhalable bosentan microparticles with the capability of delivery to the peripheral region of the lungs and enhanced bioavailability have been formulated for PAH. The bosentan microparticles were prepared by the co-spray-drying method with bosentan hydrate and mannitol at different weight ratios. The bosentan microparticles were then characterized for their physicochemical properties, in vitro dissolution behavior, and in vitro aerodynamic performance. The in vivo pharmacokinetics and pathological characteristics were evaluated in a monocrotaline-induced rat model of PAH after intratracheal powder administration of bosentan microparticles, in comparison to orally administered bosentan hydrate. The highest performance bosentan microparticles, named SDBM 1:1, had irregular and porous shape. These microparticles had not only the significantly highest aerosol performance (MMAD of 1.91 μm and FPF of 51.68%) in the formulations, but also significantly increased dissolution rate, compared with the raw bosentan hydrate. This treatment to the lungs was also safe, as evidenced by the cytotoxicity assay. Intratracheally administered SDBM 1:1 elicited a significantly higher C_max and AUC_0-t that were over 10 times higher, compared with those of the raw bosentan hydrate administered orally in the same dose. It also exhibited ameliorative effects on monocrotaline-induced pulmonary arterial remodeling, and right ventricular hypertrophy. The survival rate of the group administrated SDBM1:1 intratracheally was 0.92 at the end of study (Positive control and orally administrated groups were 0.58 and 0.38, respectively). In conclusion, SDBM 1:1 showed promising in vitro and in vivo results with the dry powder inhalation. The inhaled bosentan microparticles can be considered as a potential alternative to oral bosentan hydrate for the treatment of PAH.

Pulmonary Vascular Disease as a Systemic and Multisystem Disease

Pulmonary arterial hypertension (PAH) is a disease of progressive pulmonary vascular remodeling due to abnormal proliferation of pulmonary vascular endothelial and smooth muscle cells and endothelial dysfunction. PAH is a multisystem disease with systemic manifestations and complications. This article covers the chronic heart failure syndrome, including the systemic consequences of right ventricle-pulmonary artery uncoupling and neurohormonal activation, skeletal and respiratory muscle effects, systemic endothelial dysfunction and coronary artery disease, systemic inflammation and infection, endocrine and metabolic changes, the liver and gut axis, sleep, neurologic complications, and skin and iron metabolic changes.

TMEM16A Regulates Pulmonary Arterial Smooth Muscle Cells Proliferation via p38MAPK/ERK Pathway in High Pulmonary Blood Flow-Induced Pulmonary Arterial Hypertension

OBJECTIVE

Pulmonary arterial hypertension (PAH) is a complex disease of the small pulmonary arteries that is mainly characterized by vascular remodeling. It has been demonstrated that excessive proliferation of pulmonary arterial smooth muscle cells (PASMCs) plays a pivotal role in vascular remodeling during PAH. The present study was undertaken to explore the role of TMEM16A in regulating PASMCs proliferation in high pulmonary blood flow-induced PAH.

METHODS

Aortocaval shunt surgery was undertaken to establish an animal model. Pulmonary artery pressure and pulmonary vascular structure remodeling (PVSR) were tested. Immunohistochemical staining and Western blot were performed to investigate the expression of TMEM16A. The proliferation of PASMCs was tested by the MTT assay. After treating PASMCs with TMEM16A-siRNA, the expression of proliferating cell nuclear antigen (PCNA), phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK), and phosphorylated extracellular signal-regulated kinase (p-ERK) signaling in PASMCs were tested.

RESULTS

PAH and PVSR developed 11 weeks postoperation. Elevated expression of TMEM16A accompanied by high expression of PCNA in pulmonary arteries of the shunt group was observed. The increased proliferation of PASMCs and increased expression of TMEM16A and PCNA, along with activated p-p38MAPK and p-ERK signaling in PASMCs of the shunt group, were all attenuated by siRNA-specific TMEM16A knockdown.

CONCLUSION

TMEM16A regulates PASMCs proliferation in high pulmonary blood flow-induced PAH, and the p38MAPK/ERK signaling pathway is probably involved.

Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease

Pulmonary edema is a common clinical entity caused by the extravascular movement of fluid into the pulmonary interstitium and alveoli. The four physiologic categories of edema include hydrostatic pressure edema, permeability edema with and without diffuse alveolar damage (DAD), and mixed edema where there is both an increase in hydrostatic pressure and membrane permeability. As radiographic manifestations and etiologies are varied, an appreciation for both the common and uncommon manifestations and causes of pulmonary edema is essential for accurate diagnosis.

TRPV1 genetic polymorphisms and risk of COPD or COPD combined with PH in the Han Chinese population

COPD is a common chronic disease with genetic predisposition. TRPV1 is mainly expressed in peripheral neuron which widely exists in entire respiratory tract. In present study, we aimed to study the relationship between single nucleotide polymorphisms (SNPs) of transient receptor potential vanilloid-1 (TRPV1) and the risk of chronic obstructive pulmonary disease (COPD) or COPD combined with pulmonary hypertension (PH) in Chinese Han population. A total of 1019 individuals, including 506 healthy volunteers and 513 COPD patients (150 patients combined with PH among them) were recruited in this study. Genomic DNA were extracted and sequenced. Genotype and allele frequencies of the TRPV1 SNPs among COPD, COPD combined with PH and control groups were compared. Then, the association of TRPV1 SNPs and smoking status were analyzed. Genotype frequencies of SNP rs3744683 had a significant difference in COPD patients with PH patients compared with control (p = 0.006) or COPD patients without PH patients (p = 0.016). Likewise, SNP rs3744683 was remarkedly associated with the risk of COPD (p = 0.004) in current-smoker groups which phenomenon was not observed in nonsmoker or former-smoker groups. Compared with the control group, there was a significant difference for the distribution of SNP rs4790521 alleles in the COPD group (p = 0.041). For further, logical regression analysis showed that SNP rs3744683 genotype of “TC” was a protective factor for PH in COPD patients compared with the genotype of “TT” (OR = 0.364, 95%CI = 0.159–0.829, p = 0.016). Our findings firstly revealed the relevance between TRPV1 SNPs and the risk for COPD/COPD combined with PH.

Eicosapentaenoic acid ameliorates pulmonary hypertension via inhibition of tyrosine kinase Fyn

Pulmonary arterial hypertension (PAH) is a multifactorial disease characterized by pulmonary arterial vasoconstriction and remodeling. Src family tyrosine kinases, including Fyn, play critical roles in vascular remodeling via the inhibition of STAT3 signaling. EPA is known to inhibit Fyn kinase activity. This study investigated the therapeutic potential and underlying mechanisms of EPA and its metabolite, resolvin E1 (RvE1), to treat PAH using monocrotaline-induced PAH model rats (MCT-PAH), human pulmonary artery endothelial cells (HPAECs), and human pulmonary artery smooth muscle cells (HPASMCs). Administration of EPA 1 and 2 weeks after MCT injection both ameliorated right ventricular hypertrophy, remodeling and dysfunction, and medial wall thickening of the pulmonary arteries and prolonged survival in MCT-PAH rats. EPA attenuated the enhanced contractile response to 5-hydroxytryptamine in isolated pulmonary arteries of MCT-PAH rats. Mechanistically, the treatment with EPA and RvE1 or the introduction of dominant-negative Fyn prevented TGF-β2-induced endothelial-to-mesenchymal transition and IL-6-induced phosphorylation of STAT3 in cultured HPAECs. EPA and RvE1 suppressed Src family kinases' activity as evaluated by their phosphorylation status in cultured HPAECs and HPASMCs. EPA and RvE1 suppressed vasocontraction of rat and human PA. Furthermore, EPA and RvE1 inhibited the enhanced proliferation and activity of Src family kinases in HPASMCs derived from patients with idiopathic PAH. EPA ameliorated PAH's pathophysiology by mitigating vascular remodeling and vasoconstriction, probably inhibiting Src family kinases, especially Fyn. Thus, EPA is considered a potent therapeutic agent for the treatment of PAH.

BCR-ABL1-Negative Chronic Myeloproliferative Neoplasms and Pulmonary Hypertension: A Prospective Long-Term Follow-up Study of the Impact of Pulmonary Hypertension on Survival

PURPOSE

To assess the prevalence of PHT in patients with BCR-ABL1-negative CMPN and to evaluate impact of PHT on survival during long-term follow-up.

PATIENTS AND METHODS

A total of 122 patients with BCR-ABL1-negative CMPN underwent transthoracic echocardiographic (TTE) evaluation at the beginning of study. Patients undergoing PHT on TTE examination were also evaluated by a pulmonologist. Patients were divided into 3 groups. Group A comprised patients with CMPN-related PHT; group B, patients with no PHT; and group C, patients with PHT due to secondary causes. Patients were evaluated again every 3 to 6 months.

RESULTS

PHT was detected in 33 (27%) of 122 patients. Eight (6.5%) had CMPN-related PHT and the remaining 25 (20.5%) had non-CMPN-related PHT. Positivity for JAK2 V617F mutation in the study population was 72.9%. Groups were similar with respect to hematologic parameters and gender. Follow-up times were as follows: median (range) time from diagnosis to TTE and study end were 34 (1-158) months and 107 (16-251) months, respectively, and from TTE to study end was 88 (7-110) months. No significant differences found among the groups in terms of median time from diagnosis to TTE, follow-up, and overall survival.

CONCLUSION

BCR-ABL1-negative CMPN patients had a lower prevalence of PHT compared to earlier studies. There was no statistically significant difference in median overall survival between patients with or without PHT. This may be because patients with PHT were asymptomatic and PHT was mild. The impact of PHT on survival was negligible.

Long Noncoding RNA Rps4l Mediates the Proliferation of Hypoxic Pulmonary Artery Smooth Muscle Cells

Pulmonary hypertension (PH) is a rare and fatal disorder involving the vascular remodeling of pulmonary arteries mediated by the enhanced proliferation of pulmonary artery smooth muscle cells (PASMCs). Long noncoding RNAs are a subclass of regulatory molecules with diverse cellular functions, but their role in PH remains largely unexplored. We aimed to identify and determine the functions of long noncoding RNAs involved in hypoxia-induced PH and PASMC proliferation. RNA sequencing in a hypoxic mouse model identified hypoxia-regulated long noncoding RNAs, including Rps4l. Rps4l expression was significantly reduced in PH-model mice and hypoxic PASMCs. The subcellular localization of Rps4l was detected by RNA fluorescence in situ hybridization and quantification of nuclear/cytoplasmic RNA. Rps4l overexpression rescued pulmonary arterial hypertension features, as demonstrated by right ventricle hypertrophy, right ventricular systolic pressure, hemodynamics, cardiac function, and vascular remodeling. At the cellular level, Rps4l overexpression weakened cell viability and proliferation and suppressed cell cycle progression. Potential Rps4l-binding proteins were identified via RNA pull-down followed by mass spectrometry, RNA immunoprecipitation, and microscale thermophoresis. These results indicated that Rps4l is associated with and affects the stabilization of ILF3 (interleukin enhancer-binding factor 3). Rps41 further regulates the levels of HIF-1α and consequently leads to hypoxia-induced PASMC proliferation and migration. Our results showed that in hypoxic PASMCs, Rps4l expression decreases due to regulation by hypoxia. This decrease affects the proliferation, migration, and cell cycle progression of PASMCs through ILF3/HIF-1α. These results provide a theoretical basis for further investigations into the pathological mechanism of hypoxic PH and may provide insight for the development of novel treatments.

Multifactorial Pulmonary Hypertension in Systemic Sclerosis

Pulmonary hypertension is a progressive disease often associated with multifactorial etiology. The impact of multiple causes contributing to rapid progression of the disease, to our knowledge has not been thoroughly reviewed in literature. The cause of pulmonary hypertension is often implied from pre-existing comorbidities. A diagnostic and management challenge exists when simultaneous presence of multiple plausible causes exist. Studies evaluating the rapid progression of symptoms in multifactorial pulmonary hypertension to this effect are lacking. We present a case of pulmonary arterial hypertension (PAH) in a patient with rapidly progressing symptoms to highlight the need for an early and thorough diagnostic workup.

Implications of immune-inflammatory responses in smooth muscle dysfunction and disease

In the past few decades, solid evidence has been accumulated for the pivotal significance of immunoinflammatory processes in the initiation, progression, and exacerbation of many diseases and disorders. This groundbreaking view came from original works by Ross who first described that excessive inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall is essential for the pathogenesis of atherosclerosis (Ross, Nature 1993; 362(6423): 801–9). It is now widely recognized that both innate and adaptive immune reactions are avidly involved in the inflammation-related remodeling of many tissues and organs. When this state persists, irreversible fibrogenic changes would occur often culminating in fatal insufficiencies of many vital parenchymal organs such as liver, lung, heart, kidney and intestines. Thus, inflammatory diseases are becoming the common life-threatening risk for and urgent concern about the public health in developed countries (Wynn et al., Nature Medicine 2012; 18(7): 1028–40). Considering this timeliness, we organized a special symposium entitled “Implications of immune/inflammatory responses in smooth muscle dysfunction and disease” in the 58th annual meeting of the Japan Society of Smooth Muscle Research. This symposium report will provide detailed synopses of topics presented in this symposium; (1) the role of inflammasome in atherosclerosis and abdominal aortic aneurysms by Fumitake Usui-Kawanishi and Masafumi Takahashi; (2) Mechanisms underlying the pathogenesis of hyper-contractility of bronchial smooth muscle in allergic asthma by Hiroyasu Sakai, Wataru Suto, Yuki Kai and Yoshihiko Chiba; (3) Vascular remodeling in pulmonary arterial hypertension by Keizo Hiraishi, Lin Hai Kurahara and Ryuji Inoue.

Effect of membrane insertion for tricuspid regurgitation using immersed-boundary lattice Boltzmann method

BACKGROUND

Tricuspid regurgitation is treated by valve repair or replacement. However, these methods have limitations, and alternative treatment methods are therefore required.

OBJECTIVES

In this study, a new method of tricuspid valve treatment using artificial membrane insertion is analyzed. We performed tricuspid valve simulations using an artificial membrane inserted into the right ventricle (RV) or right atrium (RA).

METHODS

We use the lattice Boltzmann method with the immersed boundary condition to model the structural motion of the valve leaflet. The effect of membrane insertion is analyzed in terms of the stress, force, and impulse on the valve leaflet, along with the velocity, pressure, jet volume, and Reynolds stress in the flow field.

RESULTS

While the use of either membrane (RA or RV) leads to improved valve closure relative to the use of no membrane, the RV membrane is more effective than the RA membrane in achieving improved valve closure. In addition, a larger membrane area with a shorter distance between the leaflet and membrane increases membrane efficacy.

CONCLUSION

Our results suggest that membrane insertion can form an effective new method for the treatment of tricuspid regurgitation.

Prognostic value of six-minute walk distance at a South American pulmonary hypertension referral center

Six-minute walk distance (6MWD) assessment is recommended for pulmonary arterial hypertension multidimensional risk stratification. However, current 6MWD cut-off values were mainly derived from North American and European pulmonary arterial hypertension registries. Therefore, it is unknown if such cut-off values broadly apply to other geographical populations. In this study, we aimed to identify 6MWD cut-off values for Brazilian pulmonary arterial hypertension patients and to contrast our findings to current international Pulmonary Hypertension guidelines recommendations. One-hundred four consecutive pulmonary arterial hypertension patients were allocated in groups according to their 6MWD, considering 50 m as a clinically relevant 6MWD difference. Next, patients were categorized into different 6MWD ranges based on similar survival rates in each group: < 250 m, 250–400 m, and >400 m. The study outcome was all-cause mortality and transplantation according to the 6MWD range. Survival was truncated at five years. Median follow-up period was 4.35 years (0.48–5.00). Survival rates at 1, 2, 3, and 5 years were 96%, 89%, 81%, and 73%, respectively. Cox analyses adjusted for age, sex, and pulmonary arterial hypertension etiology showed that 6MWD < 250 m and >400 m were associated with higher and lower risk of all-cause mortality and transplantation. According to Harrell's c-statistic, the prognostic discrimination of the 6MWD cut-off value identified by the current study was 0.70 while international Pulmonary Hypertension guidelines 6MWD cut-offs value was 0.61. In conclusion, our findings suggest that 6MWD geographical variations should be considered when assessing risk stratification in pulmonary arterial hypertension.

Notch3 signalling and vascular remodelling in pulmonary arterial hypertension

Notch signalling is critically involved in vascular morphogenesis and function. Four Notch isoforms (Notch1–4) regulating diverse cellular processes have been identified. Of these, Notch3 is expressed almost exclusively in vascular smooth muscle cells (VSMCs), where it is critically involved in vascular development and differentiation. Under pathological conditions, Notch3 regulates VSMC switching between the contractile and synthetic phenotypes. Abnormal Notch3 signalling plays an important role in vascular remodelling, a hallmark of several cardiovascular diseases, including pulmonary arterial hypertension (PAH). Because of the importance of Notch3 in VSMC (de)differentiation, Notch3 has been implicated in the pathophysiology of pulmonary vascular remodelling in PAH. Here we review the current literature on the role of Notch in VSMC function with a focus on Notch3 signalling in pulmonary artery VSMCs, and discuss potential implications in pulmonary artery remodelling in PAH.

Cathepsin S: investigating an old player in lung disease pathogenesis, comorbidities, and potential therapeutics

Dysregulated expression and activity of cathepsin S (CTSS), a lysosomal protease and a member of the cysteine cathepsin protease family, is linked to the pathogenesis of multiple diseases, including a number of conditions affecting the lungs. Extracellular CTSS has potent elastase activity and by processing cytokines and host defense proteins, it also plays a role in the regulation of inflammation. CTSS has also been linked to G-coupled protein receptor activation and possesses an important intracellular role in major histocompatibility complex class II antigen presentation. Modulated CTSS activity is also associated with pulmonary disease comorbidities, such as cancer, cardiovascular disease, and diabetes. CTSS is expressed in a wide variety of immune cells and is biologically active at neutral pH. Herein, we review the significance of CTSS signaling in pulmonary diseases and associated comorbidities. We also discuss CTSS as a plausible therapeutic target and describe recent and current clinical trials examining CTSS inhibition as a means for treatment.

Lung function in relation to six-minute walk test in pulmonary hypertension

Background: Pulmonary hypertension (PH) is a progressive disorder of the pulmonary circulation, associated with diverse medical conditions. Exercise limitation is the most prominent symptom in PH. Exercise capacity, commonly assessed through a six-minute walk test (6MWT), correlates with both functional status and survival in PH. Few studies have analysed the relation between respiratory function and exercise limitation. Therefore, we investigated the relationship between resting pulmonary function, exercise capacity, and exertional desaturation, assessed through the 6MWT, in unselected PH patients.

Methods: Fifty consecutive patients with PH diagnosis, referred for pulmonary function testing (lung volume, spirometry, and diffusing capacity for carbon monoxide (DLCO)) and 6MWT, were recruited at Molinette University Hospital, Turin.

Results: The majority of the patients (54%) had PH due to left heart disease. Airway obstruction (FEV₁/VC-ratio < 0.7) was found in 46% of the patients and they performed significantly worse in the 6MWT than unobstructed patients (307 m vs. 377 m). Patients with PH due to left heart disease also performed significantly poorer 6MWT when airway obstruction was present (305 m vs. 389 m). Twenty-two patients (44%) presented exertional desaturation upon 6MWT. Lower DLCO divided by the alveolar volume (DLCO/VA), FEV₁/VC-ratios and resting PaO₂-values were significantly correlated with exertional desaturation after adjustments for age, sex, BMI, and smoking habits. DLCO/VA was the main determinant of exertional desaturation in a stepwise regression model.

Conclusions: Spirometric parameters of airway obstruction were related to walk distance and exercise-induced desaturation in PH patients. This suggests a place for spirometry in clinical monitoring of PH patients.

TMEM16A regulates the cell cycle of pulmonary artery smooth muscle cells in high-flow-induced pulmonary arterial hypertension rat model

High-flow-induced pulmonary arterial hypertension (PAH) has attained global notoriety, the mechanism of which remains elusive. The present study investigated the regulation of Anoctamin-1, also known as transmembrane member 16A (TMEM16A), in the cell cycle progression of pulmonary artery smooth muscle cells (PASMCs) from a PAH rat model induced by high pulmonary blood flow. A total of 30 Sprague-Dawley rats were randomly assigned into control, sham and shunt groups. A rat model of high pulmonary blood flow-induced PAH was established by surgery using abdominal aorta-inferior vena cava fistula. Right ventricular pressure, right ventricular hypertrophy index and pulmonary arteriole structural remodeling were assessed 11 weeks following operation. The cell cycle statuses of PASMCs was assessed via flow cytometry, whereas western blot analysis was performed to measure the expression of cyclin D1, CDK2, p27KIP and cyclin E in primary PASMCs isolated from rats. The expression of cyclin E and cyclin D1 was revealed to be increased in the shunt group compared with the control group, which was accompanied with an increased expression of TMEM16A in the shunt group. Changes in the ratio of PASMCs in the G0/G1, S and G2/M phases of cycle induced by PAH were reversed by TMEM16A knockdown. The expression of cyclin E and cyclin D1 in the shunt group was significantly higher compared with the control group in vitro, which was reversed by TMEM16A-siRNA transfection. In conclusion, TMEM16A may be involved in high pulmonary blood flow-induced PAH by regulating PASMC cell cycle progression.

Pulmonary hypertension: From an orphan disease to a global epidemic

[No abstract. Showing first paragraph of article]Pulmonary hypertension is a progressive disease characterized by an elevation of pulmonary artery pressure and pulmonary vascular resistance, leading to right ventricular failure and death. It remains a challenging chronic progressive disease, but the current interest and advent of medical therapy in the last 20 years has significantly changed the perception of medical community in this disease. Pulmonary hypertension is not a specific disease; the majority of cases present with other diseases and various pathological processes that affect the pulmonary vasculature, and consequently increase pulmonary pressure and vascular resistance.