Pulmonary Arterial Hypertension Therapy Research Articles

Hemodynamic Response to Oral Vasodilator Therapy in Systemic Sclerosis-Related Pulmonary Hypertension.

Although classified as group 1 pulmonary arterial hypertension (PAH), patients with systemic sclerosis-related pulmonary hypertension (SSc-PH) experience poorer clinical response to PAH therapy and increased mortality compared to those with idiopathic PAH. Due to heterogeneity in phenotypes, identifying patients likely to respond to therapy is challenging. The goal of this study was to determine clinical factors associated with hemodynamic response, defined by a > 20% reduction in pulmonary vascular resistance on repeat right heart catheterization. We applied a time-to-event model using a retrospective cohort of 39 patients with precapillary SSc-PH, defined by a mean pulmonary artery pressure of ≥ 25mmHg and pulmonary arterial wedge pressure (PAWP) ≤ 15mmHg on right heart catheterization. Patients with PAWP ≤ 8mmHg were nearly fourfold more likely to achieve a hemodynamic response compared to those with PAWP > 8mmHg (HR 3.88; 95% CI: 1.20, 12.57); each 1mmHg increase in PAWP was associated with a decreased hazard for hemodynamic response (HR 0.84; 95% CI: 0.70, 1.00). In patients with precapillary SSc-PH, PAWP was associated with time to hemodynamic response, suggesting the importance of subclinical cardiac disease in determining hemodynamic response to oral vasodilator therapy.

β3 adrenergic agonism: A novel pathway which improves right ventricular-pulmonary arterial hemodynamics in pulmonary arterial hypertension.

Efficacy of therapies that target the downstream nitric oxide (NO) pathway in pulmonary arterial hypertension (PAH) depends on the bioavailability of NO. Reduced NO level in PAH is secondary to "uncoupling" of endothelial nitric oxide synthase (eNOS). Stimulation of β3 adrenergic receptors (β3 ARs) may lead to the recoupling of NOS and therefore be beneficial in PAH. We aimed to examine the efficacy of β3 AR agonism as a novel pathway in experimental PAH. In hypoxia (5 weeks) and Sugen hypoxia (hypoxia for 5 weeks + SU5416 injection) models of PAH, we examined the effects of the selective β3 AR agonist CL316243. We measured echocardiographic indices and invasive right ventricular (RV)-pulmonary arterial (PA) hemodynamics and compared CL316243 with riociguat and sildenafil. We assessed treatment effects on RV-PA remodeling, oxidative stress, and eNOS glutathionylation, an oxidative modification that uncouples eNOS. Compared with normoxic mice, RV systolic pressure was increased in the control hypoxic mice (p < 0.0001) and Sugen hypoxic mice (p < 0.0001). CL316243 reduced RV systolic pressure, to a similar degree to riociguat and sildenafil, in both hypoxia (p < 0.0001) and Sugen hypoxia models (p < 0.03). CL316243 reversed pulmonary vascular remodeling, decreased RV afterload, improved RV-PA coupling efficiency and reduced RV stiffness, hypertrophy, and fibrosis. Although all treatments decreased oxidative stress, CL316243 significantly reduced eNOS glutathionylation. β3 AR stimulation improved RV hemodynamics and led to beneficial RV-PA remodeling in experimental models of PAH. β3 AR agonists may be effective therapies in PAH.

Long-term impact of add-on sequential triple combination therapy in pulmonary arterial hypertension: real world experience.

Sequential triple combination therapy is recommended for pulmonary arterial hypertension (PAH) patients who are not at therapeutic goal on dual therapy, but long-term data on efficacy and safety is scarce. To assess the long-term impact of sequential triple combination therapy in patients with PAH who are not at goal on dual combination therapy. We performed a retrospective observational study in a racially/ethnically diverse cohort of consecutive PAH patients on a stable dual therapy regimen who remained in intermediate- or high-risk category and were subsequently initiated on sequential triple combination therapy. We studied interval change in functional, echocardiographic, and hemodynamic parameters, REVEAL 2.0 risk category and ERS/ESC 2022 simplified four-strata risk category. Multivariate logistic regression analysis was performed to identify independent predictors of successful risk reduction (achievement or maintenance of REVEAL 2.0 low-risk category). Kaplan-Meier survival curves were created to assess the effect of risk reduction on survival. Out of 414 PAH patients seen in our program, 55 patients received add-on sequential triple combination regimen and had follow-up hemodynamic data. The mean age was 57 years, with 85% women. The most common etiology of PAH was idiopathic/heritable (41.8%). Most patients were WHO functional class III (76.4%), and 34.5% of patients were in high-risk category (REVEAL 2.0). On a median follow-up of 68 weeks, there was a significant improvement in WHO Functional Class (p < 0.001), six-minute walk distance (35 m) with 61.8% of patients achieving low-risk status by REVEAL 2.0, and a 28% of patients' improvement in pulmonary vascular resistance. Female gender was identified as a strong predictor of successful risk reduction, whereas Hispanic ethnicity estimated right atrial pressure on echocardiogram and pericardial effusion predicted lower probability of risk reduction. Patients who achieved or maintained low-risk status had significantly improved survival. Add-on sequential triple combination therapy significantly increased functional, echocardiographic, and hemodynamic parameters with improvement in risk category and survival.

The Future of PAH Treatment

Pulmonary arterial hypertension (PAH) is a devastating disease mediated by vasoconstriction and vascular remodeling of the pulmonary vasculature. Current therapies target the imbalance of vasoconstrictors and vasorelaxants in 3 pathways: nitric oxide, prostacyclin, and endothelin. While these have extended lifespans for PAH patients, significant morbidity and mortality remains. Notably, the progress in PAH therapy for over a decade has utilized these same 3 pathways. Fortunately, several new treatment options utilizing different mechanisms are emerging and will be reviewed here.

Cytokines as prognostic biomarkers in pulmonary arterial hypertension.

Risk stratification and assessment of disease progression in patients with pulmonary arterial hypertension (PAH) are challenged by the lack of accurate disease-specific and prognostic biomarkers. To date, brain natriuretic peptide (BNP) and/or its N-terminal fragment (NT-proBNP) are the only markers for right ventricular dysfunction used in clinical practice, in association with echocardiographic and invasive haemodynamic variables to predict outcome in patients with PAH. This study was designed to identify an easily measurable biomarker panel in the serum of 80 well-phenotyped PAH patients with idiopathic, heritable or drug-induced PAH at baseline and at first follow-up. The prognostic value of identified cytokines of interest was secondly analysed in an external validation cohort of 125 PAH patients. Among the 20 biomarkers studied with the multiplex Ella platform, we identified a three-biomarker panel composed of β-NGF, CXCL9 and TRAIL that were independently associated with prognosis both at the time of PAH diagnosis and at the first follow-up after initiation of PAH therapy. β-NGF and CXCL9 were predictors of death or transplantation, whereas high levels of TRAIL were associated with a better prognosis. Furthermore, the prognostic value of the three cytokines was more powerful for predicting survival than usual non-invasive variables (New York Heart Association Functional Class, 6-min walk distance and BNP/NT-proBNP). The results were validated in a fully independent external validation cohort. The monitoring of β-NGF, CXCL9 and TRAIL levels in serum should be considered in the management and treatment of patients with PAH to objectively guide therapeutic options.

Possibilities of long-term effective treatment of idiopathic pulmonary arterial hypertension by replacing sildenafil with riociguat and using sequential combination therapy: case report

Modern pathogenetic therapy of idiopathic pulmonary arterial hypertension (IPAH), a severe life-threatening cardiovascular disease of unknown etiology, leads to a positive clinical effect due to reverse remodeling of the vessels of the microvasculature of the lungs. Highly effective drugs of specific therapy that act on the main targets of pathogenesis have now been introduced into clinical practice.The presented clinical case of a patient with diagnosed in 2014 IPAH with an initial functional class III according to the WHO classification demonstrates high long-term efficacy and safety of specific therapy based on the use of the soluble guanylate cyclase stimulator riociguat for 5 years after replacing previous therapy with sildenafil with further implementation of the strategy of sequential combination therapy due to the addition of ambrisentan and selexipag.

Advances in targeted therapy for pulmonary arterial hypertension in children.

Pulmonary arterial hypertension (PAH) is a rare and devastating pulmonary vascular disease that is associated with a variety of diseases of any age in childhood onset. •Therapeutic strategies for targeted drugs for PAH in children are based almost exclusively on data from adult studies and clinical experience of pediatric specialists. •Due to the complex etiology of PAH in children and the relative lack of clinical trial data, the selection of appropriate targeted drug therapy remains difficult. •We redefine the definition of pulmonary arterial hypertension in children and summarize the progress of targeted therapy of pulmonary arterial hypertension in children in the past ten years. • The dosage and adverse reactions were summarized, and the mechanism of action was drawn according to the available targeted drugs. It can provide theoretical support for the development of guidelines and treatment strategies for the diagnosis and treatment of pulmonary arterial hypertension in children.

Novel and emerging therapies in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH), defined as a mean pulmonary artery pressure exceeding 20 mmHg with a pulmonary vascular resistance of 3 or more Wood units, is an incurable and progressive condition. The cornerstone of PAH treatment is pulmonary vasodilators, which act on the pulmonary vasculature to reduce pulmonary pressures and pulmonary vascular resistance and prevent progression to right heart failure. The number of available pulmonary vasodilator therapies has grown markedly in the last 10 years, alongside a rapidly expanding body of literature establishing strategies for their use. Up-front combination therapy, typically with two pulmonary vasodilator medications, has become the standard of care based on landmark trials showing superior outcomes over single therapies alone. Complex risk stratification matrices have begun to see widespread use as tools with which to guide changes in PAH therapies for individual patients. Strategies for using the pulmonary vasodilators in common use continue to be evaluated in trials exploring concepts such as up-front triple combination therapy and substitution of vasodilators for patients not meeting therapeutic goals. Alongside established pulmonary vasodilator therapies for PAH, there is a broad spectrum of experimental therapies that are being studied for the disease. These include both more conventional medications that act on pathways targeted by existing vasodilator therapies as well as non-vasodilator treatments with novel methods of action, that may act both to vasodilate and to address the detrimental changes of pulmonary arterial and right ventricular remodeling. Many of these emerging medications are the focus of active phase 2 and 3 trials. Finally, there has been significant interest in therapeutic pathways that are well established in left heart failure, with the hope of adapting strategies that may be efficacious in PAH and right heart failure as well. These include explorations of pathways treated by goal-directed medical therapy as well as device therapies such as pacing, resynchronization therapy, and cardiac monitoring devices. Many of these options show promise and may represent a complementary approach to treatment of PAH, allowing for multimodal therapy alongside pulmonary vasodilators to improve patient outcomes.

Combination therapy of newly diagnosed intermediate-risk pulmonary arterial hypertension: A review

Advancements in the specific therapy of pulmonary arterial hypertension (PAH) and new combination therapy strategies and escalation treatment over the past decade have significantly improved disease control, slowed its progression, and improved quality of life and patient survival. This review provides a detailed discussion of current strategies for PAH-specific therapy available in the Russian Federation for patients with classical and non-classical PAH who fail to achieve treatment goals and remain at intermediate risk of disease progression/mortality.

The thromboxane receptor antagonist NTP42 promotes beneficial adaptation and preserves cardiac function in experimental models of right heart overload.

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary artery pressure leading to right ventricular (RV) failure. While current PAH therapies improve patient outlook, they show limited benefit in attenuating RV dysfunction. Recent investigations demonstrated that the thromboxane (TX) A2 receptor (TP) antagonist NTP42 attenuates experimental PAH across key hemodynamic parameters in the lungs and heart. This study aimed to validate the efficacy of NTP42:KVA4, a novel oral formulation of NTP42 in clinical development, in preclinical models of PAH while also, critically, investigating its direct effects on RV dysfunction. The effects of NTP42:KVA4 were evaluated in the monocrotaline (MCT) and pulmonary artery banding (PAB) models of PAH and RV dysfunction, respectively, and when compared with leading standard-of-care (SOC) PAH drugs. In addition, the expression of the TP, the target for NTP42, was investigated in cardiac tissue from several other related disease models, and from subjects with PAH and dilated cardiomyopathy (DCM). In the MCT-PAH model, NTP42:KVA4 alleviated disease-induced changes in cardiopulmonary hemodynamics, pulmonary vascular remodeling, inflammation, and fibrosis, to a similar or greater extent than the PAH SOCs tested. In the PAB model, NTP42:KVA4 improved RV geometries and contractility, normalized RV stiffness, and significantly increased RV ejection fraction. In both models, NTP42:KVA4 promoted beneficial RV adaptation, decreasing cellular hypertrophy, and increasing vascularization. Notably, elevated expression of the TP target was observed both in RV tissue from these and related disease models, and in clinical RV specimens of PAH and DCM. This study shows that, through antagonism of TP signaling, NTP42:KVA4 attenuates experimental PAH pathophysiology, not only alleviating pulmonary pathologies but also reducing RV remodeling, promoting beneficial hypertrophy, and improving cardiac function. The findings suggest a direct cardioprotective effect for NTP42:KVA4, and its potential to be a disease-modifying therapy in PAH and other cardiac conditions.

Left Heart Disease Phenotype in Elderly Patients with Pulmonary Arterial Hypertension: Insights from the Italian PATRIARCA Registry.

Pulmonary arterial hypertension (PAH) in the elderly is often associated with left heart disease (LHD), prompting concerns about the use of pulmonary vasodilators. The PATRIARCA registry enrolled ≥70 year-old PAH or chronic thromboembolic pulmonary hypertension (CTEPH) patients at 11 Italian centers from 1 December 2019 through 15 September 2022. After excluding those with CTEPH, post-capillary PH at the diagnostic right heart catheterization (RHC), and/or incomplete data, 23 (33%) of a total of 69 subjects met the criteria proposed in the AMBITION trial to suspect LHD. Diabetes [9 (39%) vs. 6 (13%), p = 0.01] and chronic kidney disease [14 (61%) vs. 12 (26%), p = 0.003] were more common, and the last RHC pulmonary artery wedge pressure [14 ± 5 vs. 10 ± 3 mmHg, p < 0.001] was higher and pulmonary vascular resistance [5.56 ± 3.31 vs. 8.30 ± 4.80, p = 0.02] was lower in LHD than non-LHD patients. However, PAH therapy was similar, with 13 (57%) and 23 (50%) subjects, respectively, taking two oral drugs. PAH medication patterns remained comparable between LHD and non-LHD patients also when the former [37, 54%] were identified by atrial fibrillation and echocardiographic features of LHD, in addition to the AMBITION criteria. In this real-world snapshot, elderly PAH patients were treated with pulmonary vasodilators, including combinations, despite a remarkable prevalence of a LHD phenotype.

Effects of COVID-19 pandemic on the management of pulmonary hypertension

The coronavirus of 2019 (COVID-19) disrupted delivery of healthcare. Patients with pulmonary hypertension (PH), especially pulmonary arterial hypertension (PAH), require significant resources for both diagnosis and management and are at high risk for decompensation due to disruption in their care. A survey consisting of 47 questions related to the care of patients with PH was designed by the American College of Chest Physicians 2020–2021 Pulmonary Vascular Disease (PVD) NetWork Steering Committee and sent to all members of the PVD NetWork, as well as the multiple other professional networks for PH. Participation was voluntary and anonymous. Responses were collected from November 2020 through February 2021. Ninety-five providers responded to this survey. The majority (93%) believe that care of PH patients has been affected by the pandemic. Sixty-seven percent observed decreased referrals for PH evaluation. Prior to the pandemic, only 15% used telemedicine for management of PH patients compared to 84% during the pandemic. Telemedicine was used most for follow up of selected low-risk patients (49%). While 22% respondents were completely willing to prescribe new PAH therapy via telemedicine, 11% respondents were completely unwilling. Comfort levels differed based on type of medication being prescribed. Over 90% of providers experienced disruptions in obtaining testing and 31% experienced disruptions in renewal or approval of medications. Overall, providers perceived that the COVID-19 pandemic caused significant disruption of care for PH patients. Telemedicine utilization increased but was used mostly in low-risk patients. Some providers had a decreased level of comfort prescribing PAH therapy via telemedicine encounters.

Exercise Training as a Non-Pharmacological Therapy for Patients with Pulmonary Arterial Hypertension: Home-Based Rehabilitation Program and Training Recommendations.

Pulmonary arterial hypertension (PAH) is a chronic and progressive disorder with a poor prognosis associated with non-specific symptoms, including general weakness, shortness of breath on exertion, and decreased muscle strength and endurance. Despite recent significant progress in the field of PAH therapy, many patients are still characterized by a dynamic course of the disease, a significant reduction in physical performance, a constantly deteriorating quality of life, and limited activity in everyday life. Thus, the main goal of PAH therapy is to ensure an acceptable level of quality of life as early as possible in the course of the disease, reduce the progression of symptoms and, if possible, improve the prognosis, which is still poor. The perception of the importance of activity and exercise has changed significantly in recent years, and rehabilitation dedicated to PAH patients is now considered to be one of the new adjuvant treatment options. Currently, there is insufficient data on what form, frequency, and intensity of exercise are required for the best results. Nevertheless, exercise training (ET) is necessary in order to reverse the accompanying PAH impairment of exercise capacity and, without additional clinical risk, to maximize the benefits of pharmacotherapy. This review summarizes the current state of knowledge on the rehabilitation of PAH patients and presents the available rehabilitation models. In addition, it includes a ready-to-use, illustrated, safe home rehabilitation program with recommendations for its use. Utilizing ET as an adjuvant treatment option to improve the functional capacity and quality of life of patients may enhance the clinical effectiveness of therapeutic management and contribute to the improvement of the quality of care for patients suffering from PAH. The beneficial effect of exercise training on the development of symptoms improves the clinical course of the disease, and a lower incidence of adverse events can lead to a reduction in health care expenditure.

Multiple Intravenous Bolus Dosing and Invasive Hemodynamic Assessment in a Hypoxia-Induced Mouse Pulmonary Artery Hypertension Model.

Pulmonary arterial hypertension (PAH) is a progressive life-threatening disease, primarily affecting small pulmonary arterioles of the lung. Currently, there is no cure for PAH. It is important to discover new compounds that can be used to treat PAH. The mouse hypoxia-induced PAH model is a widely used model for PAH research. This model recapitulates human clinical manifestations of PAH Group 3 disease and is an important research tool to evaluate the effectiveness of new experimental therapies for PAH. Research using this model often requires the administration of compounds in mice. For a compound that needs to be given directly into the bloodstream, optimizing intravenous (IV) administration is a key part of the experimental procedures. Ideally, the IV injection system should permit multiple injections over a set time course. Although the mouse hypoxia-induced PAH model is very popular in many laboratories, it is technically challenging to perform multiple IV bolus dosing and invasive hemodynamic assessment in this model. In this protocol, we present step-by-step instructions on how to carry out multiple IV bolus dosing via mouse jugular vein and perform arterial and right ventricle catheterization for hemodynamic assessment in mouse hypoxia-induced PAH model.

Early selexipag initiation and long-term outcomes: insights from randomised controlled trials in pulmonary arterial hypertension.

Further understanding of when to initiate therapies in pulmonary arterial hypertension (PAH) is important to improve long-term outcomes. Post hoc analyses of GRIPHON (NCT01106014) and exploratory analyses of TRITON (NCT02558231) suggested benefit of early selexipag initiation on long-term outcomes, despite no additional benefit versus initial double combination on haemodynamic and functional parameters in TRITON. Post hoc analyses investigated the effect of early selexipag initiation on disease progression and survival in a large, pooled PAH cohort. Data from newly diagnosed (≤6 months) PAH patients from GRIPHON and TRITON were pooled. Patients on active therapy with selexipag (pooled selexipag group) were compared with those on control therapy with placebo (pooled control group). Disease progression end-points were defined as per the individual studies. Hazard ratios (HR) and 95% CI for time to first disease progression event up to end of double-blind treatment (selexipag/placebo) +7 days and time to all-cause death up to end of study were estimated using Cox regression models. The pooled dataset comprised 649 patients, with 44% on double background therapy. Selexipag reduced the risk of disease progression by 52% versus control (HR: 0.48; 95% CI: 0.35-0.66). HR for risk of all-cause death was 0.70 (95% CI: 0.46-1.10) for the pooled selexipag versus control group. Sensitivity analyses accounting for the impact of PAH background therapy showed consistent results, confirming the appropriateness of data pooling. These post hoc, pooled analyses build on previous insights, further supporting selexipag use within 6 months of diagnosis, including as part of triple therapy, to delay disease progression.

Abstract 9453: The Role of Repeated PET/MRI Hybrid Imaging in Pulmonary Arterial Hypertension Patients Receiving Specific Therapy, Four-Year Observation

Introduction: PET/MRI hybrid imaging in pulmonary arterial hypertension (PAH) provides new prognostic parameters, which identify the group of patients who potentially might benefit from early PAH therapy escalation. In previous study we confirmed that right ventricle (RV) metabolic alterations are linked with PAH hemodynamics and both precede clinical deterioration. Hypothesis: Repeating PET/MRI scans improves PAH patients’ management. Methods: Twenty stable patients (49.9±14.9 y.o.) had second simultaneous PET/MRI scans during follow up visit (FU) after 24 months from baseline scans. SUV RV /SUV LV ratio was used to estimate and compare cardiac glucose uptake before and after PAH therapy escalation. Next, observation was extended to 48 months in total. Results: Between baseline and FU visits, 16 patients needed therapy escalation (mostly to prostacyclin); median SUV RV /SUV LV (observed in PET) has lowered with improvement in both RV ejection fraction (MRI) and mean pulmonary artery pressure (catheterization). In long observation (48 months) mean time to clinical worsening was 25.2±17.1 months. Cut-off value of PET-derived SUV RV /SUV LV in ROC analysis was 0.54, suggesting that even subtle shift in cardiac glucose metabolism in PAH may result in worse prognosis. PAH patients with baseline SUV RV /SUV LV higher than 0.54 had significantly worse prognosis in the 48-months observation (log-rank test, p=0.003). Finally, patients with follow-up SUV RV /SUV LV ratio higher than 1.14 had still significantly worse prognosis despite of previously escalated treatment during FU visits (log-rank test, p=0.04, Figure). Conclusions: Repeated PET/MRI imaging provides non-invasive assessment of PAH patients’ hemodynamics, prognosis and helps to determine effectiveness of targeted therapy affecting subtle cardiac metabolic changes. Even single PET/MRI assessment in PAH patients may help to determine long-term prognosis and to plan appropriate PAH therapy.

Abstract 14938: Endothelial Cell-Targeted Nanoparticle Delivery of Crispr/Cas9 Plasmid Dna Disrupts Endothelial Epas1 in Adult Rats and Inhibits Experimental Pah

Introduction: Pulmonary arterial hypertension (PAH) is a devastating disease characterized by obliterative vascular remodeling that leads to right heart failure and death. HIF-2α (hypoxia-inducible factor-2α) activation in lung endothelial cells is obligatory to obliterative pulmonary vascular remodeling in PAH patients and animal PAH models. Hypothesis: Endothelial cell-targeted nanoparticle can deliver plasmid DNA expressing the CRISPR/Cas9 system to disrupt Epas1 (encoding HIF-2α) selectively in endothelial cells in adult rats and inhibit PAH in monocrotaline rats. Methods: To target endothelium for robust genome editing, we developed poly(ethylene glycol) methyl ether- block -poly(lactide-co-glycolide) (PEG- b -PLGA) copolymer-based nanoparticle formulated with polyethyleneimine. A single i.v. administration of mixture of nanoparticles and plasmid DNA expressing Cas9 controlled by rat Cdh5 promoter and guide RNAs targeting Epas1 driven by U6 promoter induced highly efficient genome editing in endothelial cells in 6-weeks old SD rats. Rat Cdh5 -Cas9 plasmid DNA with scramble guide RNA were injected as a control group. One week after nanoparticle administration, the rats were injected with a single dose of monocrotaline (MCT) to induce PAH. At 4 weeks post-MCT, hemodynamic measurement of right ventricular systolic pressure RVSP and weight ratio of right ventricular versus left ventricular plus septum (RV/LV+S), an indicator of RV hypertrophy were determined. Results: Single administration of mixture of nanoparticles and CRISPR Cdh5 plasmid DNA caused diminished HIF-2α protein expression selectively in endothelial cells indicating highly efficient genome editing. Genomic editing-mediated disruption of Epas1 in endothelial cells reduced RVSP and right ventricular hypertrophy as well as obliterative pulmonary vascular remodeling in MCT-induced PAH rats. Conclusions: These findings demonstrate robust genome editing of Epas1 via EC-targeted nanoparticle delivery of CRISPR-Cas9 plasmid DNA in adult rats leading to attenuated PAH in MCT rats, suggesting EC-targeted nanoparticle delivery of genome editing system to disrupt PAH-causing gene(s) in ECs is a promising precision gene therapy of PAH in patients.

Abstract 11565: Improvement in Cardiopulmonary Function in a Rat Model of Pulmonary Arterial Hypertension Observed With RKER-012, a Novel Activin Receptor Type II Ligand Trap, was Associated With Reduced Markers of Inflammation and Fibrosis in the Right Ventricle

Pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary vascular resistance, impaired cardiac output, and right ventricle (RV) overload. PAH is associated with imbalanced TGF-ß signaling, marked by elevated SMAD2/3 signaling, which is associated with inflammation and fibrosis contributing to heart failure. Initially, the RV can compensate for increased pressure due to its adaptive contractility, but chronic pressure overload leads to maladaptive RV remodeling through inflammatory and fibrotic pathways. Current therapies for PAH are primarily vasodilators which do not treat the underlying pathology. RKER-012 is a research form of KER-012, an investigational modified ActRIIB ligand trap designed to inhibit signaling through SMAD2/3. We investigated RKER-012’s mechanism of prevention of cardiac pathology in a Sugen/Hypoxia (SH) PAH model. Rats received a subcutaneous (SQ) dose of 25 mg/kg Sugen 5416 under hypoxic conditions. For 3 weeks, SH rats received vehicle (SH-VEH) or 10 mg/kg RKER-012 (SH-RKER-012) twice weekly SQ. Control rats received VEH twice weekly in normoxic conditions. Systolic pulmonary arterial pressure (sPAP) and Fulton index (FI) were measured. qPCR of RV tissue was used to evaluate the mechanism of RKER-012 in this model. SH-VEH rats had increased FI and sPAP (both p≤0.0001) compared to NX, consistent with development of cardiac and pulmonary impairment. Relative to SH-VEH, RKER-012 reduced increased FIand prevented increased sPAP (both p≤0.001) in SH rats so that sPAP did not differ from NX. Relative to NX, SH-VEH had increased RV expression of fibrotic markers such as Timp1, Col1a1, Col3a1, Runx2, and LOX (all p≤0.05). In contrast, SH-RKER-012 rats had reduced expression of Timp1, Col1a1, Col3a1, Runx2 and LOX (all p≤0.05) relative to SH-VEH. Inflammation markers CD68 and MCP1 (both p≤0.05) were increased in SH-VEH compared to NX. CD68 expression was reduced in SH-RKER-012 (p≤0.01) compared to NX but MCP1 expression was not affected (p=0.54). These results support that RKER-012 attenuated upregulation of key inflammation and fibrosis markers in a PAH preclinical model and suggest that KER-012 has a distinct mechanism from vasodilation and could be developed as a cardioprotective treatment for PAH.

Profibrotic Effects of Endothelin-1 on Fibroblasts Are Mediated by Aldosterone in Vitro: Relevance to the Pathogenesis and Therapy of Systemic Sclerosis and Pulmonary Arterial Hypertension.

Endothelin-1 (ET-1) is a vasoactive and profibrotic peptide that plays a pivotal role in diseases such as systemic sclerosis (SSc) and pulmonary arterial hypertension (PAH), by inducing fibrosis and vascular remodeling. Such effects may be sustained by the induction of aldosterone production and reactive oxygen species (ROS). We have used fibroblasts obtained from skin of healthy donors and SSc patients and commercial fibroblasts from lung to evaluate whether ET-1 is able to stimulate ROS production directly or indirectly through aldosterone induction. We found that ET-1 receptors are present in all types of fibroblasts analyzed, whereas the expression of mineralocorticoid receptor (MCR) is lower in dermal fibroblasts from healthy donors (HDFs) compared to fibroblasts derived from lung (HPFs) or from skin of SSc patients (SScHDFs). ET-1 induces ROS production in HDFs and SScHDFs after 24 h of incubation involving its receptor B (ETB), whereas aldosterone exerts its effects after 40 min of incubation. Moreover, ROS production was inhibited by the pre-incubation of cells with MCR inhibitor. Our results indicate that ET-1 induces ROS indirectly through aldosterone production suggesting that aldosterone may play a pivotal role in the pathogenesis of SSc and PAH.

Medication use by US patients with pulmonary hypertension associated with chronic obstructive pulmonary disease: a retrospective study of administrative data

BackgroundPulmonary hypertension (PH) is a serious complication of chronic obstructive pulmonary disease (COPD). While clinical guidelines recommend specific drug therapies for pulmonary arterial hypertension (PAH), these drug therapies are not recommended for PH due to lung disease.MethodsThis was a retrospective cohort study using the Optum® Clinformatics® Data Mart from January 2009–September 2019. An algorithm was designed to identify adults with ≥ 2 ICD-9-CM or ICD-10-CM diagnosis codes for PH and with ≥ 2 diagnosis codes for COPD. Sensitivity analyses were conducted among subgroups of patients with evidence of a right heart catheterization (RHC) or pulmonary function test (PFT). Patient characteristics, medications used, and durations of use of PAH and COPD medications were analyzed.ResultsA total of 25,975 patients met the study inclusion criteria. Their mean age was 73.5 (SD 10.0) years and 63.8% were female. Medications targeting PAH were prescribed to 643 (2.5%) patients, most frequently a phosphodiesterase-5 inhibitor (2.1%) or an endothelin receptor antagonist (0.75%). Medications for COPD were prescribed to 17,765 (68.4%) patients, most frequently an inhaled corticosteroid (57.4%) or short-acting beta agonist (50.4%). The median durations of use ranged from 4.9 to 12.8 months for PAH medications, and from 0.4 to 5.9 months for COPD medications. Of the subgroup of patients with RHC (N = 2325), 257 (11.1%) were prescribed a PAH medication and 1670 (71.8%) used a COPD medication. Of the subgroup with a PFT (N = 2995), 58 (1.9%) were prescribed a PAH medication and 2100 (70.1%) a COPD medication.ConclusionsPatients with PH associated with COPD were identified in a US administrative claims database. Very few of these patients received any of the medications recommended for PAH, and only about two thirds received medications for COPD.