Treatment of pulmonary arterial hypertension

Chemical Constituents with Anti-Proliferative Activity on Pulmonary Arterial Smooth Muscle Cells from the Roots of Anthriscus sylvestris (L.) Hoffm

A chemical investigation of Anthriscus sylvestris roots led to the isolation and characterization of two new nitrogen-containing phenylpropanoids (1-2) and two new phenol glycosides (8-9), along with fifteen known analogues. Structure elucidation was based on HRESIMS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD). In addition, compounds 3, 6, 9-10, 12, and 17 exhibited inhibitory effects against the abnormal proliferation of pulmonary arterial smooth muscle cells with IC50 values ranging from 10.7 ± 0.6 to 57.1 ± 1.1 μM.

The diverging roles of insulin-like growth factor binding proteins in pulmonary arterial hypertension

Pulmonary hypertension (PH) is a progressive, severe and to date not curable disease of the pulmonary vasculature. Alterations of the insulin-like growth factor 1 (IGF-1) system are known to play a role in vascular pathologies and IGF-binding proteins (IGFBPs) are important regulators of the bioavailability and function of IGFs. In this study, we show that circulating plasma levels of IGFBP-1, IGFBP-2 and IGFBP-3 are increased in idiopathic pulmonary arterial hypertension (IPAH) patients compared to healthy individuals. These binding proteins inhibit the IGF-1 induced IGF-1 receptor (IGF1R) phosphorylation and exhibit diverging effects on the IGF-1 induced signaling pathways in human pulmonary arterial cells (i.e. healthy as well as IPAH-hPASMCs, and healthy hPAECs). Furthermore, IGFBPs are differentially expressed in an experimental mouse model of PH. In hypoxic mouse lungs, IGFBP-1 mRNA expression is decreased whereas the mRNA for IGFBP-2 is increased. In contrast to IGFBP-1, IGFBP-2 shows vaso-constrictive properties in the murine pulmonary vasculature. Our analyses show that IGFBP-1 and IGFBP-2 exhibit diverging effects on IGF-1 signaling and display a unique IGF1R-independent kinase activation pattern in human pulmonary arterial smooth muscle cells (hPASMCs), which represent a major contributor of PAH pathobiology. Furthermore, we could show that IGFBP-2, in contrast to IGFBP-1, induces epidermal growth factor receptor (EGFR) signaling, Stat-3 activation and expression of Stat-3 target genes. Based on our results, we conclude that the IGFBP family, especially IGFBP-1, IGFBP-2 and IGFBP-3, are deregulated in PAH, that they affect IGF signaling and thereby regulate the cellular phenotype in PH.

Identification of MACC1 as a potential biomarker for pulmonary arterial hypertension based on bioinformatics and machine learning

BACKGROUND

Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by abnormal early activation of pulmonary arterial smooth muscle cells (PASMCs), yet the underlying mechanisms remain to be elucidated.

METHODS

Normal and PAH gene expression profiles were obtained from the Gene Expression Omnibus (GEO) database and analyzed using gene set enrichment analysis (GSEA) to uncover the underlying mechanisms. Weighted gene co-expression network analysis (WGCNA) and machine learning methods were deployed to further filter hub genes. A number of immune infiltration analysis methods were applied to explore the immune landscape of PAH. Enzyme-linked immunosorbent assay (ELISA) was employed to compare MACC1 levels between PAH and normal subjects. The important role of MACC1 in the progression of PAH was verified through Western blot and real-time qPCR, among others.

RESULTS

39 up-regulated and 7 down-regulated genes were identified by 'limma' and 'RRA' packages. WGCNA and machine learning further narrowed down the list to 4 hub genes, with MACC1 showing strong diagnostic capacity. In vivo and in vitro experiments revealed that MACC1 was highsly associated with malignant features of PASMCs in PAH.

CONCLUSIONS

These findings suggest that targeting MACC1 may offer a promising therapeutic strategy for treating PAH, and further clinical studies are warranted to evaluate its efficacy.

Future Perspectives of Pulmonary Arterial Hypertension: A Review of Novel Pipeline Treatments and Indications

Pulmonary arterial hypertension is characterized by elevated blood pressure and pathological changes in the pulmonary arterioles, leading to the development of right-heart failure and potentially fatal outcomes if left untreated. This review aims to provide an overview of novel drugs or formulations and new drug indications for pulmonary arterial hypertension that are currently in phases II-III of randomized controlled trials, and describe the rationale for the use of these targeted therapies, as well as their efficacy, safety profile, and impact on quality of life and survival. The literature research was conducted using data from ClinicalTrials.gov for the period between 1 January 2016 up to 31 December 2022. The population of interest includes individuals aged ≥ 18 years who have been diagnosed with pulmonary arterial hypertension. The review selection criteria included trials with recruiting, enrolling by invitation, active, terminated or completed status in 2022 and 2023. A total of 24 studies were selected for evaluation based on the inclusion and exclusion criteria. This review summarizes the updated information from randomized clinical trials involving novel therapies for pulmonary arterial hypertension. However, larger clinical trials are required to validate their clinical safety and effects. In the future, clinicians should choose therapies based on the patient's individual situation and requirements when developing treatment strategies.

Effects of 5-Week Oral Acetazolamide on Incremental Cycling Exercise in Pulmonary Arterial and Chronic Thromboembolic Pulmonary Hypertension: A Randomized Placebo-Controlled, Double-Blinded, Crossover Trial

INTRODUCTION

Acetazolamide (AZA) improves nocturnal and daytime blood oxygenation in patients with pulmonary vascular disease (PVD), defined as pulmonary arterial and distal chronic thromboembolic pulmonary hypertension (CTEPH), and may improve exercise performance.

METHODS

We investigated the effect of 5 weeks of AZA (250 mg bid) versus placebo on maximal load during incremental cycling ramp exercise in patients with PVD studied in a randomized controlled, double-blind, crossover design, separated by > 2 weeks of washout.

RESULTS

Twenty-five patients (12 pulmonary arterial hypertension, 13 CTEPH, 40% women, age 62 ± 15 years) completed the trial according to the protocol. Maximum load was similar after 5 weeks of AZA versus placebo (113 ± 9 vs. 117 ± 9 watts [W]), mean difference -4 W (95% CI: -9 to 1, p = 0.138). With AZA, maximum (max)-exercise partial pressure of O2 (PaO2) was significantly higher by 1.1 kPa (95% CI: 0.5-1.8, p = 0.003), while arterial pH and partial pressure of CO2 were significantly lower. Gas exchange threshold was reached at a higher load with AZA (108 ± 8 W vs. 97 ± 8 W) and was therefore delayed by 11 W (95% CI: 3-19, p = 0.013), while the ventilatory equivalent for O2 and CO2 were significantly higher at both the max-exercise and gas exchange threshold with AZA versus placebo.

CONCLUSION

AZA for 5 weeks did not significantly change maximum exercise capacity in patients with PVD despite a significant increase in PaO2. The beneficial effects of increased blood oxygenation may have been diminished by increased ventilation due to AZA-induced metabolic acidosis and increased dyspnea.

Case report: Extracorporeal life support as a successful bridge to recovery in an incident case of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance (PVR) due to vascular remodeling of the small pulmonary arteries. In advanced RV failure or severe hypoxemia, extra corporeal life support (ECLS) is now to be considered, with the objective to bridge patients back to their baseline clinical state while waiting or right after lung transplantation, or bridge to pharmacological optimization of PAH (i.e., bridge to recovery). We describe herein a case of a 30-year-old woman (gravida 6, para 6) with an incident case of heritable PAH revealed by refractory hypoxemia. Despite the use of mechanical ventilation and fluid optimization, the patient remained profoundly hypoxemic. ECLS was then initiated to avoid tissue hypoxia. The mechanical option chosen was peripheral femoro-femoral venoarterial extracorporeal membrane oxygen (VA-ECMO), percutaneously implanted. Due to the absence of evidence of chronic respiratory disease or chronic thromboembolic pulmonary hypertension, this severe pre-capillary pulmonary hypertension was attributed to PAH. Therefore, epoprostenol infusion and an association of oral treatments (bosentan and tadalafil) were administered. A dramatic improvement was observed, allowing decannulation 7 days after the initiation of pharmacological treatment. After 29 days, the patient was discharged from the hospital with epoprostenol, bosentan, and tadalafil. The assessment has been completed by positive research on mutations (c.741C > G, p.Tyr247) corresponding to a loss of function of the bone morphogenetic protein receptor 2 (BMPR2) gene. The final diagnosis was heritable PAH. The use of ECLS has been well demonstrated in patients with PAH complicated by acute RV failure or refractory hypoxemia in the "bridge-to-transplantation" strategy. Only a few reports have described the use of ECLS as a "bridge-to-recovery" with PAH drugs in untreated or undertreated PAH patients, but none has described such a rapid improvement with resolution of refractory hypoxemia. More studies are needed to assess the benefits and limitations of the "bridge-to-recovery" strategy and to identify the patients most likely to benefit from it.

Comparative adherence of macitentan versus ambrisentan and bosentan in Australian patients with pulmonary arterial hypertension: a retrospective real-world database study

AIM

Bosentan, ambrisentan, and macitentan are endothelin receptor antagonists (ERAs), currently available in Australia for treatment of pulmonary arterial hypertension (PAH). This study assessed the comparative adherence of these ERAs for PAH in Australian patients.

METHODS

This retrospective, observational study used data for adults with PAH from the Services Australia 10% Pharmaceuticals Benefits Scheme (PBS) dataset (01/2006-10/2020). The primary outcome was treatment adherence (i.e. receiving ≥80% of ERA doses over 12 months). Secondary outcomes were time to treatment change (add-on or switch) and overall survival.

RESULTS

The study included 436 patients who took bosentan (n = 200), ambrisentan (n = 69), or macitentan (n = 167). Treatment adherence was significantly greater in patients who received macitentan (65.3%) versus ambrisentan (56.5%) and bosentan (58.0%), with odds ratios (ORs; 95% CI) of 0.51 (0.30-0.88; p = 0.016) for bosentan versus macitentan and 0.48 (0.24-0.96; p = 0.037) for ambrisentan versus macitentan. The median time to treatment change was 47.2 and 43.4 months for bosentan and ambrisentan, respectively (not calculated for macitentan because of insufficient duration of data).

LIMITATIONS AND CONCLUSIONS

Real-world data for Australian patients with PAH showed that treatment adherence for ERAs was suboptimal. Adherence was higher for macitentan compared with ambrisentan and bosentan.

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.

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

INTRODUCTION

Real-world data on the comparative effectiveness of endothelin receptor antagonists (ERAs; macitentan, bosentan, ambrisentan) for pulmonary arterial hypertension (PAH), particularly in Asian countries, are scarce. We evaluated the persistence of these ERAs before and after macitentan approval in Japan (2015).

METHODS

We used real-world data from the Japanese Medical Data Vision administrative claims database between April 2008 and November 2020. Patients with PAH were identified from the dataset. Persistence to ERA treatment before and after approval of macitentan in Japan was defined as the time between start of the index ERA and treatment discontinuation or death. Propensity score adjustment was applied to minimize confounding effects among treatment groups.

RESULTS

In the pre-macitentan approval cohort, 153 and 51 patients received bosentan and ambrisentan, respectively. In the post-macitentan approval cohort, 331, 284, and 91 patients received macitentan, bosentan, and ambrisentan, respectively. Unadjusted median persistence for ambrisentan- and bosentan-treated patients was 19 and 10 months, respectively (adjusted HR 0.87 [95% CI 0.61-1.24]; P = 0.434 [bosentan as reference]). In the post-macitentan approval cohort, unadjusted median persistence was 18 months for macitentan-treated patients versus 6 and 8 months for ambrisentan- and bosentan-treated patients, respectively. Adjusted HRs for ambrisentan and bosentan were 1.48 (95% CI 1.12-1.95; P = 0.006) and 1.63 (95% CI 1.30-2.04; P < 0.001 [macitentan as reference]), respectively.

CONCLUSIONS

Real-world data for Japanese patients with PAH showed that persistence was significantly higher for macitentan, versus ambrisentan and bosentan, since its approval.

The Emerging Therapeutic Role of Prostaglandin E2 Signaling in Pulmonary Hypertension

Mild-to-moderate pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD). It is characterized by narrowing and thickening of the pulmonary arteries, resulting in increased pulmonary vascular resistance (PVR) and ultimately leading to right ventricular dysfunction. Pulmonary vascular remodeling in COPD is the main reason for the increase of pulmonary artery pressure (PAP). The pathogenesis of PH in COPD is complex and multifactorial, involving chronic inflammation, hypoxia, and oxidative stress. To date, prostacyclin and its analogues are widely used to prevent PH progression in clinical. These drugs have potent anti-proliferative, anti-inflammatory, and stimulating endothelial regeneration properties, bringing therapeutic benefits to the slowing, stabilization, and even some reversal of vascular remodeling. As another well-known and extensively researched prostaglandins, prostaglandin E2 (PGE2) and its downstream signaling have been found to play an important role in various biological processes. Emerging evidence has revealed that PGE2 and its receptors (i.e., EP1-4) are involved in the regulation of pulmonary vascular homeostasis and remodeling. This review focuses on the research progress of the PGE2 signaling pathway in PH and discusses the possibility of treating PH based on the PGE2 signaling pathway.

Retrospective cohort study of pulmonary arterial hypertension associated with connective tissue disease effect on patients' prognosis

OBJECTIVE

The objectives of this study are to clarify clinical characteristics and recognize prognostic factors of CTD-PAH patients.

METHODS

A retrospective cohort study of consecutive patients with documented CTD-PAH diagnosis from Jan 2014 to Dec 2019 was conducted, the ones who have other comorbid conditions that cause PH were excluded. Survival functions were plotted using the Kaplan-Meier method. Univariable and multivariable Cox regression analysis was applied to determine the survival-related factors.

RESULTS

In 144 patients with CTD-PAH analyzed, the median sPAP value was 52.5 (44.0, 71.0) mmHg, the overall targeted drug usage rate was 55.6%, and only 27.5% patients were given combination. Twenty-four non-PAH-CTD patients with sPAP value were included as the control group. Compared with non-PAH-CTD groups, CTD-PAH patients had worse cardiac function, higher NT-pro BNP and γ-globulin level, and lower PaCO2 level. Compared with the mild PAH group, the moderate-severe PAH group had worse cardiac function; increased Hb, HCT, and NP-pro BNP level; and decreased PaO2. Kaplan-Meier analysis showed significant difference for survival among non-PAH-CTD, mild CTD-PAH, and moderate-severe CTD-PAH groups. The univariate analyses showed that Hb, pH, and Ln (NT-pro BNP) were identified as factors significantly associated with survival, and Hb and pH showed significant association with risk of death in the multivariate model. Kaplan-Meier analysis also showed that Hb > 109.0 g/L and pH > 7.457 affected CTD-PAH patients' survival significantly.

CONCLUSIONS

PAH is not rare in CTDs patients; PAH affects CTD patients' prognosis significantly. Higher Hb and pH were associated with an increased risk of death. Key Points • Pulmonary arterial hypertension affects connective tissue disease patients' prognosis significantly. • The significantly factors associated with survival is hemoglobin, pH, and Ln (NT-pro BNP).

[Genetic counselling and testing in pulmonary arterial hypertension - A consensus statement on behalf of the International Consortium for Genetic Studies in PAH - French version]

Pulmonary arterial hypertension (PAH) is a rare disease that can be caused by (likely) pathogenic germline genomic variants. In addition to the most prevalent disease gene, BMPR2 (bone morphogenetic protein receptor 2), several genes, some belonging to distinct functional classes, are also now known to predispose to the development of PAH. As a consequence, specialist and non-specialist clinicians and healthcare professionals are increasingly faced with a range of questions regarding the need for, approaches to and benefits/risks of genetic testing for PAH patients and/or related family members. We provide a consensus-based approach to recommendations for genetic counselling and assessment of current best practice for disease gene testing. We provide a framework and the type of information to be provided to patients and relatives through the process of genetic counselling, and describe the presently known disease causal genes to be analysed. Benefits of including molecular genetic testing within the management protocol of patients with PAH include the identification of individuals misclassified by other diagnostic approaches, the optimisation of phenotypic characterisation for aggregation of outcome data, including in clinical trials, and importantly through cascade screening, the detection of healthy causal variant carriers, to whom regular assessment should be offered.

A Case of Giant Goiter Associated with Airway Stenosis Caused by Long-Term Intravenous Epoprostenol Therapy for Idiopathic Pulmonary Arterial Hypertension

Idiopathic pulmonary arterial hypertension is a progressive and life-threatening disease with pulmonary vasculature remodeling, leading to right-sided heart failure. Epoprostenol (prostaglandin I2) is highly recommended for patients with severe pulmonary arterial hypertension (PAH) categorized by the World Health Organization as functional class III or IV. It has been reported that prostaglandin I2 analogs can cause thyroid gland swelling and abnormal thyroid function. A 34-year-old woman was diagnosed with idiopathic pulmonary arterial hypertension and started receiving continuous intravenous epoprostenol. Three years after starting epoprostenol, she began complaining of neck swelling and was diagnosed with Graves' disease. The patient's thyroid function was controlled by thiamazole and levothyroxine; nevertheless, her thyroid gland enlargement worsened as the epoprostenol dose was titrated. After 20 years, she developed respiratory failure with a giant goiter leading to airway stenosis, and she passed away. The pathological autopsy confirmed a massive goiter associated with hyperthyroidism and airway stenosis. We experienced a case of idiopathic pulmonary hypertension with a giant goiter and airway stenosis after long-term intravenous epoprostenol therapy.

In the Search for Biomarkers of Pulmonary Arterial Hypertension, Are Cytokines IL-2, IL-4, IL-6, IL-10, and IFN-Gamma the Right Indicators to Use?

Pulmonary arterial hypertension (PAH) is a complex disorder characterized by increased pressure in the pulmonary arteries, leading to right heart failure. While the exact mechanisms underlying PAH are not fully understood, cytokines have been implicated in the pathogenesis of the disease. Cytokines play a crucial role in regulating immune responses and inflammation. These small proteins also play a key role in shaping the immunophenotype, which refers to the specific characteristics and functional properties of immune cells, which can have a significant impact on the development of PAH. The aim of this study was to determine the immunophenotype and the concentration of selected cytokines, IL-2, IL-4, IL-6, IL-10, and IFN-gamma, in patients diagnosed with PAH (with particular emphasis on subtypes) in relation to healthy volunteers. Based on the obtained results, we can conclude that in patients with PAH, the functioning of the immune system is deregulated as a result of a decrease in the percentage of selected subpopulations of immune cells in peripheral blood and changes in the concentration of tested cytokines in relation to healthy volunteers. In addition, a detailed analysis showed that there are statistically significant differences between the PAH subtypes and the tested immunological parameters. This may indicate a significant role of the immune system in the pathogenesis of PAH.

Sildenafil for congenital heart diseases induced pulmonary hypertension, a meta-analysis of randomized controlled trials

BACKGROUND

Sildenafil was first prescribed for angina pectoris and then for erectile dysfunction from its effects on vascular smooth muscle relaxation and vasodilatation. Recently, sildenafil has been proposed for congenital heart diseases induced pulmonary hypertension, which constitutes a huge burden on children's health and can attribute to fatal complications due to presence of unoxygenated blood in the systemic circulation. Therefore, our meta-analysis aims to further investigate the safety and efficacy of sildenafil on children population.

METHODS

We searched the following electronic databases: PubMed, Cochrane CENTRAL, WOS, Embase, and Scopus from inception to April 20th, 2022. Randomized controlled trials that assess the efficacy of using sildenafil in comparison to a placebo or any other vasodilator drug were eligible for inclusion. The inverse variance method was used to pool study effect estimates using the random effect model. Effect sizes are provided in the form of mean difference (MD) with 95% confidence intervals (CI).

RESULTS

Our study included 14 studies with (n = 849 children) with a mean age of 7.9 months old. Sildenafil showed a statistically significant decrease over placebo in mean and systolic pulmonary artery pressure (PAP) with MD -7.42 (95%CI [-13.13, -1.71], P = 0.01) and -8.02 (95%CI [-11.16, -4.88], P < 0.0001), respectively. Sildenafil revealed a decrease in mean aortic pressure and pulmonary artery/aortic pressure ratio over placebo with MD -0.34 (95%CI [-2.42, 1.73], P = 0.75) and MD -0.10 (95%CI [-0.11, -0.09], P < 0.00001), respectively. Regarding post corrective operations parameters, sildenafil had a statistically significant lower mechanical ventilation time, intensive care unit stay, and hospital stay over placebo with MD -19.43 (95%CI [-31.04, -7.81], s = 0.001), MD -34.85 (95%CI [-50.84, -18.87], P < 0.00001), and MD -41.87 (95%CI [-79.41, -4.33], P = 0.03), respectively. Nevertheless, no difference in mortality rates between sildenafil and placebo with OR 0.25 (95%CI 0.05, 1.30], P = 0.10) or tadalafil with OR 1 (95%CI 0.06, 17.12], P = 1).

CONCLUSION

Sildenafil is a well-tolerated treatment in congenital heart diseases induced pulmonary hypertension, as it has proven its efficacy not only in lowering both PAP mean and systolic but also in reducing the ventilation time, intensive care unit and hospital stay with no difference observed regarding mortality rates.

Pharmacogenomics in the Management of Pulmonary Arterial Hypertension: Current Perspectives

Pulmonary arterial hypertension (PAH) is a rare disease with heterogeneous causes that can lead to right ventricular (RV) failure and death if left untreated. There are currently 10 medications representative of five unique pharmacologic classes that are approved for treatment. These have led to significant improvements in overall clinical outcome. However, substantial variability in dosing requirements and treatment response is evident, leading to suboptimal outcome for many patients. Furthermore, dosing is empiric and iterative and can lead to delays in meeting treatment goals and burdensome adverse effects. Pharmacogenomic (PGx) associations have been reported with certain PAH medications, such as treprostinil and bosentan, and can explain some of the variability in response. Relevant genes associated with treprostinil include CYP2C8, CYP2C9, CAMK2D, and PFAS. CYP2C8 and CYP2C9 are the genes encoding the major metabolizing liver enzymes for treprostinil, and reduced function variants (*2, *3) with CYP2C9 were associated with lower treatment persistence. Additionally, a higher CYP2C9 activity score was associated with a significantly less risk of treatment discontinuation. Other genes of interest that have been explored with treprostinil include CAMK2D, which is associated with right ventricular dysfunction and significantly higher dose requirements. Similarly, PFAS is associated with lower concentrations of cyclic adenosine monophosphate and significantly higher dose requirements. Genes of interest with the endothelin receptor antagonist (ERA) class include GNG2 and CYP2C9. A genetic variant in GNG2 (rs11157866) was linked to a significantly increased rate of clinical improvement with ERAs. The *2 variant with CYP2C9 (encoding for the major metabolizing enzyme for bosentan) was significantly associated with a higher risk for elevations in hepatic aminotransferases and liver injury. In summary, this article reviews the relevant pharmacogenes that have been associated to date with dosing and outcome among patients who received PAH medications.

Inhaled iloprost is an effective alternative therapy for persistent pulmonary hypertension in newborns

Persistent pulmonary hypertension of the newborn (PPHN) is one of the diseases of the neonate with severe potential morbidity and mortality. Inhaled iloprost, a stable prostacyclin analog, has been suggested as an alternative treatment for inhaled nitric oxide (iNO). However, more data on neonates' dosing, setting, and effectiveness still needs to be solved. This study suggests using inhaled iloprost as rescue therapy for PPHN based on our experience. This was a retrospective study. The data from medical records of six newborns diagnosed with PPHN and had received inhaled iloprost from December 2019 to April 2022 were collected. Demographic and clinical features, dosing regimen, changes in oxygenation index, echocardiographic findings, and mortality were evaluated. The inhalation dose was 2-4 mcg/dose, and 3-48 inhalations per day were applied over 2-7 days. Inhaled iloprost was effective in all patients. No side effects were attributable to inhaled iloprost, and no mortality was recorded. Our experience suggests that inhaled iloprost can be used as a first-line therapy in newborn infants with PPHN when iNO is unavailable. However, there are large fluctuations in the oxygenation index due to the setting.

Frequency of acute vasodilator response (AVR) in incident and prevalent patients with pulmonary arterial hypertension: Results from the pulmonary vascular disease phenomics study

The prevalence of acute vasodilator response (AVR) to inhaled nitric oxide (iNO) during right heart catheterization (RHC) is 12% in idiopathic pulmonary arterial hypertension (IPAH). AVR, however, is reportedly lower in other disease-associated pulmonary arterial hypertension (PAH), such as connective tissue disease (CTD). The prevalence of AVR in patients on PAH therapy (prevalent cases) is unknown. We sought to determine AVR prevalence in Group 1 PH in the PVDOMICS cohort of incident and prevalent patients undergoing RHC. AVR was measured in response to 100% O2 and O2 plus iNO, with positivity defined as (1) decrease in mean pulmonary artery pressure (mPAP) by ≥10 mmHg to a value ≤40 mmHg, with no change or an increase in cardiac output (definition 1); or (2) decrease in mPAP by ≥12% and pulmonary vascular resistance by ≥30% (definition 2). AVR rates and cumulative survival were compared between incident and prevalent patients. In 338 mainly prevalent (86%) patients, positive AVR to O2-only was <2%, and 5.1% to 16.9%, based on definition 1 and 2 criteria, respectively; following O2 + iNO. IPAH AVR prevalence (4.1%-18.7%) was similar to prior reports. AVR positivity was 7.7% to 15.4% in mostly CTD-PAH prevalent cases, and 2.6% to 11.8% in other PAH groups. Survival was 89% in AVR responders versus 77% in nonresponders from PAH diagnosis, and 91% versus 86% from PVDOMICS enrollment (log-rank test p = 0.04 and p = 0.05, respectively). In conclusion, AVR in IPAH patients is similar to prior studies. AVR in non-IPAH patients was higher than previously reported. The relationship between PAH therapy, AVR response, and survival warrants further investigation.

Prostaglandin I2 suppresses the development of gut-brain axis disorder in irritable bowel syndrome in rats

In this study, we attempted to clarify a role of prostaglandin (PG) I₂ and its specific receptor, IP in the pathogenesis of irritable bowel syndrome (IBS) using a maternal separation (MS)-induced IBS model. Administration of beraprost (BPS), a specific IP agonist, improved visceral hypersensitivity and depressive state with decreased serum CRF level in the IBS rats. To clarify the mechanism of the effect of BPS, we performed serum metabolome analysis and 1-methylnicotinamide (1-MNA) was identified as a possible candidate for a clue metabolite of pathogenesis of IBS. The serum 1-MNA levels revealed inverse correlation to the level of visceral sensitivity, and positive correlation to a depression marker, immobilizing time. Administration of 1-MNA induced visceral hypersensitivity and depression with increased levels of serum CRF. Since fecal 1-MNA is known for a marker of dysbiosis, we examined the composition of fecal microbiota by T-RFLP analysis. The proportion of clostridium cluster XI, XIVa and XVIII was significantly changed in MS-induced IBS rats treated with BPS. Fecal microbiota transplant of BPS-treated rats improved visceral hypersensitivity and depression in IBS rats. These results suggest for the first time that PGI₂-IP signaling plays an important role in IBS phenotypes such as visceral hypersensitivity and depressive state. BPS modified microbiota, thereby inhibition of 1-MNA-CRF pathway, followed by improvement of MS-induced IBS phenotype. These results suggest that the PGI₂-IP signaling could be considered to be a therapeutic option for IBS.

Identification of Potent, Selective, and Peripherally Restricted Serotonin Receptor 2B Antagonists from a High-Throughput Screen

Antagonists of the serotonin receptor 2B (5-HT2B) have shown great promise as therapeutics for the treatment of pulmonary arterial hypertension, valvular heart disease, and related cardiopathies. Herein, we describe a high-throughput screen campaign that led to the identification of highly potent and selective 5-HT2B antagonists. Furthermore, selected compounds were profiled for their predicted ability to cross the blood-brain barrier. Two exemplary compounds, VU0530244 and VU0631019, were predicted to have very limited potential for brain penetration in human subjects, a critical profile for the development of 5-HT2B antagonists devoid of centrally-mediated adverse effects.

Review of the British Thoracic Society Winter Meeting 23 November 2022 23-25 November 2022

The British Thoracic Society Winter Meeting at the QEII Centre in London provided the first opportunity for the respiratory community to meet and disseminate research findings face to face since the start of the COVID-19 pandemic. World-leading researchers from the UK and abroad presented their latest findings across a range of respiratory diseases. This article aims to represent the range of the conference and as such is written from the perspective of a basic scientist, a physiotherapist and two doctors. The authors reviewed showcase sessions plus a selection of symposia based on their personal highlights. Content ranged from exciting new developments in basic science to new and unpublished results from clinical trials, delivered by leading scientists from their fields including former deputy chief medical officer Professor Sir Jonathan Van-Tam and former WHO chief scientist Dr Soumya Swaminathan.

Early Growth Response-1: Friend or Foe in the Heart?

Cardiovascular disease is a major cause of mortality and morbidity worldwide. Early growth response-1 (Egr-1) plays a critical regulatory role in a range of experimental models of cardiovascular diseases. Egr-1 is an immediate-early gene and is upregulated by various stimuli including shear stress, oxygen deprivation, oxidative stress and nutrient deprivation. However, recent research suggests a new, underexplored cardioprotective side of Egr-1. The main purpose of this review is to explore and summarise the dual nature of Egr-1 in cardiovascular pathobiology.

Loss of response to calcium channel blockers after long-term follow-up treatment in patients with idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (PAH) patients with a positive response to acute vasodilator challenge and a clinical response to calcium channel blockers (CCBs) for at least one year are traditionally designated true responders. Nevertheless, little is known about a sustained response to CCBs over longer periods of time. We evaluated the loss of response to CCBs after long-term treatment in a cohort of idiopathic PAH patients previously classified as being true responders. Our data suggest that idiopathic PAH patients can lose clinical response to CCBs even after one year of clinical stability, reinforcing the need for constant multidimensional reevaluation to assess the need for targeted PAH therapies and to classify these patients correctly.

Novel Molecular Mechanisms Involved in the Medical Treatment of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe condition with a high mortality rate despite advances in diagnostic and therapeutic strategies. In recent years, significant scientific progress has been made in the understanding of the underlying pathobiological mechanisms. Since current available treatments mainly target pulmonary vasodilation, but lack an effect on the pathological changes that develop in the pulmonary vasculature, there is need to develop novel therapeutic compounds aimed at antagonizing the pulmonary vascular remodeling. This review presents the main molecular mechanisms involved in the pathobiology of PAH, discusses the new molecular compounds currently being developed for the medical treatment of PAH and assesses their potential future role in the therapeutic algorithms of PAH.

Genetic counselling and testing in pulmonary arterial hypertension: a consensus statement on behalf of the International Consortium for Genetic Studies in PAH

Pulmonary arterial hypertension (PAH) is a rare disease that can be caused by (likely) pathogenic germline genomic variants. In addition to the most prevalent disease gene, BMPR2 (bone morphogenetic protein receptor 2), several genes, some belonging to distinct functional classes, are also now known to predispose to the development of PAH. As a consequence, specialist and non-specialist clinicians and healthcare professionals are increasingly faced with a range of questions regarding the need for, approaches to and benefits/risks of genetic testing for PAH patients and/or related family members. We provide a consensus-based approach to recommendations for genetic counselling and assessment of current best practice for disease gene testing. We provide a framework and the type of information to be provided to patients and relatives through the process of genetic counselling, and describe the presently known disease causal genes to be analysed. Benefits of including molecular genetic testing within the management protocol of patients with PAH include the identification of individuals misclassified by other diagnostic approaches, the optimisation of phenotypic characterisation for aggregation of outcome data, including in clinical trials, and importantly through cascade screening, the detection of healthy causal variant carriers, to whom regular assessment should be offered.

Tensions in Taxonomies: Current Understanding and Future Directions in the Pathobiologic Basis and Treatment of Group 1 and Group 3 Pulmonary Hypertension

In the over 100 years since the recognition of pulmonary hypertension (PH), immense progress and significant achievements have been made with regard to understanding the pathophysiology of the disease and its treatment. These advances have been mostly in idiopathic pulmonary arterial hypertension (IPAH), which was classified as Group 1 Pulmonary Hypertension (PH) at the Second World Symposia on PH in 1998. However, the pathobiology of PH due to chronic lung disease, classified as Group 3 PH, remains poorly understood and its treatments thus remain limited. We review the history of the classification of the five groups of PH and aim to provide a state-of-the-art review of the understanding of the pathogenesis of Group 1 PH and Group 3 PH including insights gained from novel high-throughput omics technologies that have revealed heterogeneities within these categories as well as similarities between them. Leveraging the substantial gains made in understanding the genomics, epigenomics, proteomics, and metabolomics of PAH to understand the full spectrum of the complex, heterogeneous disease of PH is needed. Multimodal omics data as well as supervised and unbiased machine learning approaches after careful consideration of the powerful advantages as well as of the limitations and pitfalls of these technologies could lead to earlier diagnosis, more precise risk stratification, better predictions of disease response, new sub-phenotype groupings within types of PH, and identification of shared pathways between PAH and other types of PH that could lead to new treatment targets. © 2023 American Physiological Society. Compr Physiol 13:4295-4319, 2023.

Soluble Guanylyl Cyclase Activators-Promising Therapeutic Option in the Pharmacotherapy of Heart Failure and Pulmonary Hypertension

Endogenous nitric oxide (NO)-dependent vascular relaxation plays a leading role in the homeostasis of the cardiovascular, pulmonary, and vascular systems and organs, such as the kidneys, brain, and liver. The mechanism of the intracellular action of NO in blood vessels involves the stimulation of the activity of the soluble cytosolic form of guanylyl cyclase (soluble guanylyl cyclase, sGC), increasing the level of cyclic 3'-5'-guanosine monophosphate (cGMP) in smooth muscle and subsequent vasodilation. In recent years, a new group of drugs, soluble guanylyl cyclase stimulators, has found its way into clinical practice. Based on the CHEST-1 and PATENT-1 trials, riociguat was introduced into clinical practice for treating chronic thromboembolic pulmonary hypertension (CTEPH). In January 2021, the FDA approved the use of another drug, vericiguat, for the treatment of heart failure.

Oxygen Therapy in Pulmonary Vascular Disease: A Systematic Review, Meta-Analysis, and Comment

Main pulmonary vascular diseases (PVD) with precapillary pulmonary hypertension (PH) are pulmonary arterial and chronic thromboembolic PH. Guidelines recommend supplemental oxygen therapy (SOT) for severely hypoxemic patients with PH, but evidence is scarce. The authors performed a systematic review and where possible meta-analyses on the effects of SOT on hemodynamics and exercise performance in patients with PVD. In PVD, short-term SOT significantly improved mean pulmonary artery pressure and exercise performance. There is growing evidence on the benefit of long-term SOT for selected patients with PVD regarding exercise capacity and maybe even survival.

Potential long-term effects of SARS-CoV-2 infection on the pulmonary vasculature: Multilayered cross-talks in the setting of coinfections and comorbidities

The Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and its sublineages pose a new challenge to healthcare systems worldwide due to its ability to efficiently spread in immunized populations and its resistance to currently available therapies. COVID-19, although targeting primarily the respiratory system, is also now well established that later affects every organ in the body. Most importantly, despite the available therapy and vaccine-elicited protection, the long-term consequences of viral infection in breakthrough and asymptomatic individuals are areas of concern. In the past two years, investigators accumulated evidence on how the virus triggers our immune system and the molecular signals involved in the cross-talk between immune cells and structural cells in the pulmonary vasculature to drive pathological lung complications such as endothelial dysfunction and thrombosis. In the review, we emphasize recent updates on the pathophysiological inflammatory and immune responses associated with SARS-CoV-2 infection and their potential long-term consequences that may consequently lead to the development of pulmonary vascular diseases.

A Canadian, retrospective, multicenter experience with selexipag for a heterogeneous group of pediatric pulmonary hypertension patients

Introduction

Selexipag, an oral nonprostanoid prostaglandin receptor agonist, has led to reduced morbidity and mortality in adults with pulmonary arterial hypertension (PAH). While the adult literature has been extrapolated to suggest selexipag as an oral treatment for severe pediatric pulmonary hypertension (PH), longitudinal, multicenter data on the benefits of selexipag in this population are lacking. The purpose of this study is to present a longitudinal, multicentre experience with selexipag in a relatively large cohort of pediatric PH patients and add to the existing selexipag literature.

Materials and methods

We performed a retrospective, multicenter review describing the clinical outcomes of pediatric PH patients receiving selexipag in addition to standard oral pulmonary vasodilator therapy across three Canadian centers between January 2005 and June 2021.

Results

Twenty-four pediatric patients (fifteen female) with a mean age of 9.7 (range 2.0-15.5) years were included. Of this cohort, eighteen (75.0%) were in group 1, one (4.2%) was in group 2, four (16.7%) were in group 3, and one (4.2%) was in group 4. Twenty-two (91.7%) patients were on dual PH therapy after six months. Dosing was targeted to achieve 20-30 mcg/kg/dose orally every twelve hours. Median dose after twelve months was 30 mcg/kg/dose. Twelve months following selexipag initiation, median decreases of 0.2 cm in tricuspid annular plane systolic excursion, 3.5 mmHg in right-ventricular systolic pressure, and 6.1 mmHg in mean pulmonary arterial pressure were observed; none of these changes were statistically significant. Three patients died, one clinically deteriorated and required admission to a pediatric intensive care unit, ten had gastrointestinal symptoms, and three had flushing.

Conclusion

Selexipag appears to be a safe and effective adjunctive therapy for pediatric PH patients and has a tolerable adverse effect profile aside from gastrointestinal disturbances. Additional prospective studies of changes in hemodynamics and functional classification over a longer period and with a larger sample are needed. Future research should aim to identify subgroups that stand to benefit from the addition of selexipag as well as optimal timing and dosing for the pediatric population.

Pediatric Population Pharmacokinetic Modeling and Exposure-Response Analysis of Ambrisentan in Pulmonary Arterial Hypertension and Comparison With Adult Data

This study aimed to develop a population pharmacokinetic (PK) model of ambrisentan in pediatric patients (8 to <18 years) with pulmonary arterial hypertension (PAH) and compare pediatric ambrisentan systemic exposure with previously reported adult data. Association of ambrisentan exposure with efficacy (6-minute walking distance) and safety (adverse events) were exploratory analyses. A population PK model was developed using pediatric PK data. Steady-state systemic exposure metrics were estimated for the pediatric population and compared with previously reported data in adult patients with PAH and healthy subjects. No covariates had a significant effect on PK parameters; therefore, the final covariate model was the same as the base model. The pediatric population PK model was a 2-compartment model including the effect of body weight (allometric scaling), first-order absorption and elimination, and absorption lag time. Steady-state ambrisentan exposure was similar between the pediatric and adult population when accounting for body weight differences. Geometric mean area under the concentration-time curve at steady state in pediatric patients receiving ambrisentan low dose was 3% lower than in the adult population (and similar in both populations receiving high dose). Geometric mean maximum plasma concentration at steady state in pediatric patients receiving low and high doses was 11% and 18% higher, respectively, than in the adult population. There was no apparent association in the pediatric or adult population between ambrisentan exposure and change in 6-minute walking distance or incidence of ambrisentan-related adverse events in pediatric patients. The similar ambrisentan exposure and exposure-response profiles observed in pediatric and adult populations with PAH suggests appropriateness of body-weight-based dosing in the pediatric population with PAH.

Risk stratification, prognosis, and survival in a pulmonary arterial hypertension cohort in Latin America. A multicenter study

BACKGROUND

Pulmonary arterial hypertension (PAH) guidelines suggest that achieving a low-risk profile should be the treatment goal. Our aim was to assess a risk assessment strategy based on three non-invasive variables from the ESC/ERS 2015 guidelines in a Latin American cohort.

METHODS

92 incident patients (mean [SD] age 47, 77% female, 53% idiopathic PAH) were included in this retrospective, multicenter study. Patients were stratified at baseline and at early follow-up, within the first year, using three non-invasive variables (WHO functional class, 6-minute walking distance, BNP/NT-proBNP) from the ESC/ERS 2015 risk assessment instrument. Median (IQR) follow-up was 3.11 years (3.01 years).

RESULTS

At baseline assessment, 25% of patients were at low risk, 61.9% at intermediate-risk, and 13% at high-risk. At early follow-up (median 9.5 months), 56.5% of patients were at low-risk, 40.2% at intermediate-risk, and 3.2% at high-risk (p<0.001 vs. baseline). According to risk stratification at early follow-up, one, three and five-year overall survival was 100% in the low-risk group (no deaths at five-year follow-up), and 100%, 84% (95% CI: 72-98%), and 66% (95% CI: 48-90%) respectively in the intermediate-risk group, p = 0.0003. Mortality in the high-risk patients at early follow-up was 1/3 (33.3%). One, three, and five-year event-free survival (death or transplant or first hospitalization due to worsening PAH) based on early follow-up risk assessment was higher in the low-risk group, p = 0.0003.

CONCLUSION

Our study validates a risk assessment strategy based on three non-invasive variables and confirms that early achievement of a low-risk profile should be the treatment goal.

Interest of TAPSE/sPAP ratio for noninvasive pulmonary arterial hypertension risk assessment

BACKGROUND

Although ventriculoarterial coupling is associated with better survival in pulmonary arterial hypertension (PAH), existing PAH risk assessment method has not considered echocardiographic criteria of right ventricular to pulmonary artery coupling. We aimed to test the prognostic value of the echocardiographic tricuspid annular plane systolic excursion/systolic pulmonary artery pressure (TAPSE/sPAP) ratio for noninvasive PAH risk assessment.

METHODS

We retrospectively studied a cohort of 659 incident PAH patients from 4 independent French PH centers (training cohort: n = 306, validation cohort n = 353) who underwent follow-up TAPSE/sPAP measurement in addition to previously validated noninvasive risk stratification variables. The primary composite outcome was 3-year all-cause mortality or lung transplantation from re-evaluation.

RESULTS

Mean age was 55 ± 17 years-old with a majority of female (66%). The three main PAH causes were connective tissue disease (26%), idiopathic (24%) and porto-pulmonary (19%). The primary composite outcome occurred in 71 (23%) patients. Multivariable Cox regression analysis retained 3 noninvasive low-risk criteria as associated with the primary composite outcome: NYHA I-II (p = 0.001), NTproBNP <300 ng/L or BNP <50 ng/L (p = 0.004), and TAPSE/sPAP >0.33 mm/mmHg (p = 0.004). The more the low-risk criteria achieved at follow-up, the better the event-free survival both in the training and validation cohort (log-rank p < 0.001). In the training cohort, the c-index for these 3 criteria, for COMPERA 2.0 and for the noninvasive French Pulmonary Hypertension Network method were 0.75, 95%CI(0.70-0.82), 0.72 95%CI(0.66-0.75), 0.71 95%CI(0.62-0.73), respectively.

CONCLUSION

The 3 following dichotomized low-risk criteria: TAPSE/sPAP >0.33 mm/mmHg, NYHA I-II and NTproBNP <300 ng/L or BNP <50 ng/L allow to identify low-risk PAH patients at follow-up.

mTOR contributes to endothelium-dependent vasorelaxation by promoting eNOS expression and preventing eNOS uncoupling

Clinically used inhibitors of mammalian target of rapamycin (mTOR) negatively impacts endothelial-dependent vasodilatation (EDD) through unidentified mechanisms. Here we show that either the endothelium-specific deletion of Mtor to inhibit both mTOR complexes, or depletion of Raptor or Rictor to disrupt mTORC1 or mTORC2, causes impaired EDD, accompanied by reduced NO in the serum of mice. Consistently, inhibition of mTOR decreases NO production by human and mouse EC. Specifically, inhibition of mTORC1 suppresses eNOS gene expression, due to impairment in p70S6K-mediated posttranscriptional regulation of the transcription factor KLF2 expression. In contrast to mTORC1 inhibition, a positive-feedback between MAPK (p38 and JNK) activation and Nox2 upregulation contributes to the excessive generation of reactive oxygen species (ROS), which causes eNOS uncoupling and decreased NO bioavailability in mTORC2-inhibited EC. Adeno-associated virus-mediated EC-specific overexpression of KLF2 or suppression of Nox2 restores EDD function in endothelial mTORC1- or mTORC2-inhibited mice.

The endothelium-specific inhibition of either of mammalian target of rapamycin (mTOR) complexes impairs endothelial-dependent vasodilatation (EDD), accompanied by decreased nitric oxide bioavailability in both human and mice endothelial cells.

2022 Update of indications and contraindications for lung transplantation in France

Lung transplantation (LTx) is a steadily expanding field. The considerable developments have been driven over the years by indefatigable work conducted at LTx centers to improve donor and recipient selection, combined with multifaceted efforts to overcome challenges raised by the surgical procedure, perioperative care, and long-term medical complications. One consequence has been a pruning away of contraindications over time, which has, in some ways, complicated the patient selection process. The Francophone Pulmonology Society (Société de Pneumology de Langue Française, SPLF) set up a task force to produce up-to-date working guidelines designed to assist pulmonologists in managing end-stage respiratory insufficiency, determining which patients may be eligible for LTx, and appropriately timing LTx-center referral. The task force examined the most recent literature and evaluated the risk factors that limit patient survival after LTx. Ideally, the objectives of LTx are to prolong life while also improving quality of life. The guidelines developed by the task force apply to a limited resource and are consistent with the ethical principles described below.

Indirect treatment comparison and cost-minimization analysis of riociguat versus selexipag in patients with pulmonary arterial hypertension

OBJECTIVES

The comparative efficacy between riociguat and selexipag in patients with pulmonary arterial hypertension (PAH) has never been described in literature. Our aim was to prepare indirect treatment comparison (ITC) to evaluate the cost-effectiveness of riociguat in Czechia.

METHODS

A systematic literature review identified two relevant trials with comparable endpoints to inform a Bucher ITC of relative and absolute effects. Given the comparable efficacy of riociguat and selexipag, a cost-minimization analysis (CMA) was conducted.

RESULTS

A Bucher ITC provided evidence for the comparable relative efficacy of riociguat defined as the odds of unimproved functional class III 0.761 (95% CI 0.372 to 1.558; p=0.455) compared to selexipag and a comparable absolute efficacy defined as a difference in the 6-minute walking distance of 10.560 meters (95% CI -10.692 to 31.812; p=0.330). The CMA identified riociguat as the cost-saving therapy.

CONCLUSIONS

Switching to riociguat represents the cost-saving therapy for PAH patients who were inadequately compensated with the PDE5i+ERA therapy. Consequently, riociguat has been introduced to the list of reimbursed medicines in Czechia from October 2021. Based on two global trials, we prepared the first indirect treatment comparison followed with CMA of these therapies that may improve future decision-making for PAH indications.

Focus on long non-coding RNA MALAT1: Insights into acute and chronic lung diseases

Acute lung injury (ALI) is a pulmonary illness with a high burden of morbidity and mortality around the world. Chronic lung diseases also represent life-threatening situations. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long non-coding RNA (lncRNA) and is highly abundant in lung tissues. MALAT1 can function as a competitive endogenous RNA (ceRNA) to impair the microRNA (miRNA) inhibition on targeted messenger RNAs (mRNAs). In this review, we summarized that MALAT1 mainly participates in pulmonary cell biology and lung inflammation. Therefore, MALAT1 can positively or negatively regulate ALI and chronic lung diseases (e.g., chronic obstructive pulmonary disease (COPD), bronchopulmonary dysplasia (BPD), pulmonary fibrosis, asthma, and pulmonary hypertension (PH)). Besides, we also found a MALAT1-miRNA-mRNA ceRNA regulatory network in acute and chronic lung diseases. Through this review, we hope to cast light on the regulatory mechanisms of MALAT1 in ALI and chronic lung disease and provide a promising approach for lung disease treatment.

MicroRNA-212-5p, an anti-proliferative miRNA, attenuates hypoxia and sugen/hypoxia-induced pulmonary hypertension in rodents

MicroRNAs (miRNA, miR-) play important roles in disease development. In this study, we identified an anti-proliferative miRNA, miR-212-5p, that is induced in pulmonary artery smooth muscle cells (PASMCs) and lungs of pulmonary hypertension (PH) patients and rodents with experimental PH. We found that smooth muscle cell (SMC)-specific knockout of miR-212-5p exacerbated hypoxia-induced pulmonary vascular remodeling and PH in mice, suggesting that miR-212-5p may be upregulated in PASMCs to act as an endogenous inhibitor of PH, possibly by suppressing PASMC proliferation. Extracellular vesicles (EVs) have been shown recently to be promising drug delivery tools for disease treatment. We generated endothelium-derived EVs with an enriched miR-212-5p load, 212-eEVs, and found that they significantly attenuated hypoxia-induced PH in mice and Sugen/hypoxia-induced severe PH in rats, providing proof of concept that engineered endothelium-derived EVs can be used to deliver miRNA into lungs for treatment of severe PH.

Using a knowledge translation program to facilitate guideline‐based and evidence‐based patient management: the PAH‐QuERI Extension Program

The Pulmonary Arterial Hypertension‐Quality Enhancement Research Initiative Extension Program was designed to support physicians’ adherence to pulmonary arterial hypertension (PAH) guidelines. Guidelines were followed in >95% of patients with functional class (FC) II/III, but for only 28.6% of FC IV patients (Month 36). Low adherence was driven by FC IV patients’ preference to avoid parenteral treatment.

Novel predictor of pulmonary arterial hypertension: Monocyte to HDL cholesterol ratio

Monocyte to HDL cholesterol ratio (MHR), lymphocyte to monocyte ratio (LMR), and neutrophil to lymphocyte ratio (NLR) have been proposed as novel systemic inflammatory markers. The aim of this study was to explore the association between MHR, LMR and NLR with pulmonary arterial hypertension (PAH). The study is a single-center, retrospective Cross-sectional study. The study group consisted of 73 patients with PAH and the control group 77 participants without cardiac pathology as determined by echocardiography. On admission, blood sampling to calculate MHR, LMR, NLR, and detailed clinical data were obtained. According to the Pearson test, systolic pulmonary artery pressure (PAP) value Higher MHR, NLR and lower LMR that indicates an enhanced inflammation were significantly increased in patients with PAH when compared with controls. Compared to many other inflammatory markers, these markers are widely available. positively correlated with the MHR and NLR (r:.35, P < .001 and r:.33, P < .001, respectively), but negatively correlated with LMR (r: -.26, P = .001). After multivariate logistic regression analysis, MHR, LMR, and NLR remained as significant predictors of PAH (OR: 2.651, 95% CI: 1.227-5.755, P = .007; OR: 0.647, 95% CI:0.450-0.931, P = .005; OR: 1.350, 95% CI: 1.054-1.650 P = .030, respectively).

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.

Coping styles associated with depression, health anxiety and health-related quality of life in pulmonary hypertension: cross-sectional analysis

OBJECTIVES

Pulmonary hypertension (PH) is a life-shortening disease associated with early mortality and high morbidity. With advancements in medical treatment, people are living longer with the disease, and research is now needed to explore variables that help to enhance patient-reported outcomes. This study investigated the coping strategies of individuals with PH and examined the relationship between coping, depression, health anxiety and health-related quality of life (HRQoL).

DESIGN

A cross-sectional survey design was used.

PARTICIPANTS

Participants (n=121) were recruited from membership of Pulmonary Hypertension Association (PHA) UK.

OUTCOME MEASURES

Participants completed a series of questionnaires assessing depression (Patient Health Questionnaire-9), health anxiety (Short Health Anxiety Inventory), HRQoL (emPHasis-10) and coping (Brief COPE). A principal component analysis was used to identify participants' coping profile. A series of correlational, linear and moderated multiple regression analyses were performed to examine the relationship between coping and health-related outcomes.

RESULTS

Overall, 43% participants met criteria for potential clinical depression. Depression and health anxiety were strongly associated with HRQoL, explaining 37% and 30% of variance respectively (p<0.001). A principal component analysis identified a four-component model of coping. Dimensions were named based on construct items: 'cognitive and affirmation coping' (seven items), 'passive coping' (four items), 'external coping' (seven items) and 'substance use coping' (two items). Cognitive and affirmation and external coping moderated the relationship between depression and HRQoL, with high use of these coping strategies reducing the impact of depression on HRQoL. External coping also moderated the effect of health anxiety on HRQoL.

CONCLUSIONS

The results uniquely highlight the importance of coping styles and psychological distress in predicting HRQoL in PH. Our findings indicate the importance to assess for psychological distress in this population and suggest the need to offer psychological interventions that take into account coping resources and strategies.

The Paradox of Pulmonary Vascular Resistance: Restoration of Pulmonary Capillary Recruitment as a Sine Qua Non for True Therapeutic Success in Pulmonary Arterial Hypertension

Exercise-induced increases in pulmonary blood flow normally increase pulmonary arterial pressure only minimally, largely due to a reserve of pulmonary capillaries that are available for recruitment to carry the flow. In pulmonary arterial hypertension, due to precapillary arteriolar obstruction, such recruitment is greatly reduced. In exercising pulmonary arterial hypertension patients, pulmonary arterial pressure remains high and may even increase further. Current pulmonary arterial hypertension therapies, acting principally as vasodilators, decrease calculated pulmonary vascular resistance by increasing pulmonary blood flow but have a minimal effect in lowering pulmonary arterial pressure and do not restore significant capillary recruitment. Novel pulmonary arterial hypertension therapies that have mainly antiproliferative properties are being developed to try and diminish proliferative cellular obstruction in precapillary arterioles. If effective, those agents should restore capillary recruitment and, during exercise testing, pulmonary arterial pressure should remain low despite increasing pulmonary blood flow. The effectiveness of every novel therapy for pulmonary arterial hypertension should be evaluated not only at rest, but with measurement of exercise pulmonary hemodynamics during clinical trials.

Aldehyde Dehydrogenase 2 (ALDH2) Elicits Protection against Pulmonary Hypertension via Inhibition of ERK1/2-Mediated Autophagy

Pulmonary hypertension (PH) is caused by chronic hypoxia that induces the migration and proliferation of pulmonary arterial smooth muscle cells (PASMCs), eventually resulting in right heart failure. PH has been related to aberrant autophagy; however, the hidden mechanisms are still unclear. Approximately 40% East Asians, equivalent to 8% of the universal population, carry a mutation in Aldehyde dehydrogenase 2 (ALDH2), which leads to the aggregation of noxious reactive aldehydes and increases the propensity of several diseases. Therefore, we explored the potential aspect of ALDH2 in autophagy associated with PH. In vitro mechanistic studies were conducted in human PASMCs (HPASMCs) after lentiviral ALDH2 knockdown and treatment with platelet-derived growth factor-BB (PDGF-BB). PH was induced in wild-type (WT) and ALDH2-knockout (ALDH2^−/−) mice using vascular endothelial growth factor receptor inhibitor SU5416 under hypoxic conditions (HySU). Right ventricular function was assessed using echocardiography and invasive hemodynamic monitoring. Histological and immunohistochemical analyses were performed to evaluate pulmonary vascular remodeling. EdU, transwell, and wound healing assays were used to evaluate HPASMC migration and proliferation, and electron microscopy and immunohistochemical and immunoblot assays were performed to assess autophagy. The findings demonstrated that ALDH2 deficiency exacerbated right ventricular pressure, hypertrophy, fibrosis, and right heart failure resulting from HySU-induced PH. ALDH2^−/− mice exhibited increased pulmonary artery muscularization and 4-hydroxynonenal (4-HNE) levels in lung tissues. ALDH2 knockdown increased PDGF-BB-induced PASMC migration and proliferation and 4-HNE accumulation in vitro. Additionally, ALDH2 deficiency increased the number of autophagosomes and autophagic lysosomes together with autophagic flux and ERK1/2-Beclin-1 activity in lung tissues and PASMCs, indicating enhanced autophagy. In conclusion, the study shows that ALDH2 has a protective role against the migration and proliferation of PASMCs and PH, possibly by regulating autophagy through the ERK1/2-Beclin-1 pathway.

Percutaneous Treatments for Pulmonary Hypertension: Reviewing the Growing Procedural Role for Interventional Cardiology

Pulmonary arterial hypertension is a common and highly morbid medical problem resulting in elevated pulmonary arterial pressures and pulmonary vascular resistance. Medical therapies are costly, and not always well-tolerated. Surgical therapies such as pulmonary endarterectomy and lung transplantation are limited to a small subset of patients due to various patient, disease, or institutional factors. Over the past decade, there has been growing investigation into endovascular interventional therapies for patients with pulmonary hypertension such as balloon pulmonary angioplasty and pulmonary denervation. In this review, we describe the current status, future directions, and our recommendations on technical considerations with these therapies.