Options For Pulmonary Arterial Hypertension Research Articles

Design, Development, and Evaluation of Treprostinil Embedded Adhesive Transdermal Patch.

Clinical application of treprostinil in pulmonary arterial hypertension is hampered by adverse effects caused by its high dosing frequency. The objective of this investigation was to Formulate an adhesive-type transdermal patch of treprostinil and evaluate it both in vitro and in vivo. A 32-factorial design was utilized to optimize the selected independent variables (X1: drug amount, X2: enhancer concentration) on the response variables (Y1: drug release, Y2: transdermal flux). The optimized patch was evaluated for various pharmaceutical properties, skin irritation, and pharmacokinetics in rats. Optimization results signify considerable influence (p < 0.0001) of X1 on both Y1 and Y2, as compared to X2. The optimized patch possesses higher drug content (>95%), suitable surface morphology, and an absence of drug crystallization. FTIR analysis revealed compatibility of the drug with excipients, whereas DSC thermograms indicate that the drug exists as amorphous in the patch. The adhesive properties of the prepared patch confirm adequate adhesion and painless removal, while the skin irritation study confirms its safety. A steady drug release via Fickian diffusion and greater transdermal delivery (~23.26 µg/cm2/h) substantiate the potential of the optimized patch. Transdermal therapy resulted in higher treprostinil absorption (p < 0.0001) and relative bioavailability (237%) when compared to oral administration. Overall, the results indicate that the developed drug in the adhesive patch can effectively deliver treprostinil through the skin and could be a promising treatment option for pulmonary arterial hypertension.

Focused ultrasound stimulation of the inflammatory reflex at the spleen ameliorates pulmonary arterial hypertension in rodents

Abstract Background Inflammation is a major contributor in pulmonary arterial hypertension (PAH) pathogenesis. Non-invasive, focused ultrasound stimulation (FUS) of the spleen activates the neuroimmune inflammatory reflex (IR) and suppresses systemic inflammation [1]. Purpose We aimed to explore whether daily FUS of the spleen improves haemodynamics and biomarkers by modulating the IR, in a rat model of PAH. Methods Sprague-Dawley rats (n=12) were injected s.c. with Sugen5416 (VEGF receptor inhibitor) and then, were placed in a hypoxic chamber (FiO2=10%) for 21 days, followed by 14 days of re-exposure to normoxia (FiO2=10%). At day 21, rats were randomized to either FUS (n=6) or sham-stimulation of the spleen (n=6). Each FUS- or sham-stimulation session consisted of 12 minutes. After 14 days of treatment, in a terminal experiment, right ventricular systolic pressure (RVSP) and arterial pressure were measured invasively, as well as biomarkers, in each animal (Figure 1A). Results FUS significantly reduced RVSP compared with the sham-stimulation (Mean±SEM, 50.83±3.57 mmHg vs 72.50±5.81; p=0.009), resulting in a 30% relative reduction (Figure 1B). Mean systemic arterial pressure was similar in the 2 groups (Mean±SEM, 79.83±3.73 mmHg vs. 87.00±2.95; p=0.137) (Figure 1C), as was the change in heart rate between day 1 and day 14 of treatment period (−19.53±5.36% vs. −16.79±3.1, p=0.61) (Figure 1D). Consistently, plasma brain natriuretic peptide (BNP) levels are reduced in the FUS group (119.45±19.93 ng/μl vs. 319.39±91.85; p=0.019), indicative of reduced myocardial wall stress in the FUS group (Figure 1E). Conclusion Non-invasive FUS of the spleen reduced RVSP by ∼30% and BNP without significantly affecting systemic pressure or heart rate, in rats with severe PAH. Non-invasive FUS, by modulating the IR, may exert an anti-inflammatory effect in PAH. FUS of the spleen is noninvasive, safe, widely available and easy to perform, and should be further explored as a possible therapeutic option in PAH. Funding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): Northwell Health

The Platelet-Derived Growth Factor Pathway in Pulmonary Arterial Hypertension: Still an Interesting Target?

The lack of curative options for pulmonary arterial hypertension drives important research to understand the mechanisms underlying this devastating disease. Among the main identified pathways, the platelet-derived growth factor (PDGF) pathway was established to control vascular remodeling and anti-PDGF receptor (PDGFR) drugs were shown to reverse the disease in experimental models. Four different isoforms of PDGF are produced by various cell types in the lung. PDGFs control vascular cells migration, proliferation and survival through binding to their receptors PDGFRα and β. They elicit multiple intracellular signaling pathways which have been particularly studied in pulmonary smooth muscle cells. Activation of the PDGF pathway has been demonstrated both in patients and in pulmonary hypertension (PH) experimental models. Tyrosine kinase inhibitors (TKI) are numerous but without real specificity and Imatinib, one of the most specific, resulted in beneficial effects. However, adverse events and treatment discontinuation discouraged to pursue this therapy. Novel therapeutic strategies are currently under experimental evaluation. For TKI, they include intratracheal drug administration, low dosage or nanoparticles delivery. Specific anti-PDGF and anti-PDGFR molecules can also be designed such as new TKI, soluble receptors, aptamers or oligonucleotides.

Pulmonary arterial hypertension in hereditary hemorrhagic telangiectasia associated with ACVRL1 mutation: a case report

IntroductionHereditary hemorrhagic telangiectasia is an autosomal dominant condition with an estimated prevalence of 1 in 5000. It is characterized by the presence of abnormalities of vascular structures, and may affect many organ systems, including the lungs, brain, spinal cord, gastrointestinal tract, and liver. A causative mutation is identified in approximately 97% of patients with definite hereditary hemorrhagic telangiectasia in one of three genes including a mutation in endoglin, a mutation in a locus mapped to chromosome 5, and an activin receptor-like kinase-1 (ACVRL1) mutation that is associated with an increased incidence of primary pulmonary hypertension. Pulmonary arterial hypertension is a rare (15–25 cases per million people) but severe vascular disorder. Heritable pulmonary arterial hypertension is associated with several gene mutations, with 75% having a mutation in the bone morphogenetic protein receptor 2 (BMPR2). However, the remaining 25% of patients have other associated genetic mutations including ACVLR1, which is also associated with hereditary hemorrhagic telangiectasia. Pulmonary arterial hypertension is a rare complication in patients with hereditary hemorrhagic telangiectasia (< 1% of the hereditary hemorrhagic telangiectasia population). We describe a case report with this rare occurrence.Case presentationA 70-year-old white/caucasian Irish male presented for screening for hereditary hemorrhagic telangiectasia due to a history of recurrent epistaxis (once/week) and a family history suggestive of pulmonary hypertension. Genetic testing confirmed an ACVRL1 mutation, while an echocardiogram and right heart catheterization confirmed pulmonary arterial hypertension. On examination, he had several mucocutaneous telangiectasia across his face. He was commenced on tadalafil and macitentan. However, this led to increased iron deficiency anemia and pedal edema. Selexipag was also added to his drug regime. He continues to require intermittent admissions for diuresis and blood transfusions.ConclusionThe association of hereditary hemorrhagic telangiectasia and pulmonary arterial hypertension is rare (< 1%). Here we describe a case of hereditary hemorrhagic telangiectasia complicated with pulmonary arterial hypertension as a result of an ACVRL1 mutation. We also describe the clinical challenges of treating these two conditions together, as treatment options for pulmonary arterial hypertension tend to worsen hereditary hemorrhagic telangiectasia symptoms.

Additional Use of Prostacyclin Analogs in Patients With Pulmonary Arterial Hypertension: A Meta-Analysis.

Background: Combination therapy has become an attractive option in pulmonary arterial hypertension (PAH) treatment. The aim of this study was to investigate whether additional use of prostacyclin analogs could exert any additional benefits over background targeted therapies in PAH patients. Methods: Searches were performed on PubMed, Embase, and ClinicalTrials.gov from inception to 1 October 2021. Randomized controlled trials were included if patients had been treated with prostacyclin analog-containing combination therapy and compared with the use of other PAH-specific background therapies. The bias risk and statistical analysis of the enrolled studies were performed with RevMan 5.1. Sensitivity analysis and funnel plot were used to evaluate the stability and publication bias, respectively. PROSPERO registered number CRD42021284196. Results: Ten trials involving 1828 patients were included. Prostacyclin analog treatment was associated with greater improvement in clinical worsening (risk ratio [RR], 0.70; 95% confidence interval [CI], 0.57–0.86), 6-min walk distance (mean difference [MD], 37.17 m; 95% CI, 3.01–71.33 m), NYHA/WHO functional class (RR, 1.58; 95% CI, 1.21–2.05), mean pulmonary artery pressure (MD, −9.23 mmHg; 95% CI, −17.44 to −1.03 mmHg), and cardiac index (MD, 0.41 L/min/m2; 95% CI, 0.26–0.55 L/min/m2) than the control group. No significant differences in pulmonary vascular resistance (MD, −137.22 dyn·s/cm5; 95% CI, −272.61 to −1.84 dyn·s/cm5) and all-cause mortality (RR, 0.96; 95% CI, 0.57–1.61) were found between the prostacyclin analog group and control group. Of note, more adverse events (RR, 1.07; 95% CI, 1.02–1.13) occurred in the prostacyclin analog group but no significant increase in serious adverse events (RR, 1.25; 95% CI, 0.75–2.11). Conclusion: Additional prostacyclin analog treatment exerted benefits on clinical worsening, exercise capacity, functional class, mean pulmonary artery pressure, and cardiac index in PAH patients, but it was associated with overall risk of adverse events. Clinical Trial Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021284196, identifier CRD42021284196.

Evaluation, Diagnosis, and Classification of Pulmonary Hypertension.

Pulmonary hypertension (PH) is a rare heterogenous disease characterized by elevated blood pressure in the lungs. Patients with PH require careful evaluation and management at an expert center. Understanding of the mechanisms underlying the development of PH has increased over the past two decades, and several treatment options for pulmonary arterial hypertension have emerged. Despite this progress, PH continues to carry high morbidity and mortality. The 6th World Symposium on Pulmonary Hypertension that occurred in late 2018 modified the clinical classification of PH into five groups. In this review, we focus on the evaluation and diagnosis of PH and discuss the updated clinical classification.

Emerging therapies for right ventricular dysfunction and failure.

Therapeutic options for right ventricular (RV) dysfunction and failure are strongly limited. Right heart failure (RHF) has been mostly addressed in the context of pulmonary arterial hypertension (PAH), where it is not possible to discern pulmonary vascular- and RV-directed effects of therapeutic approaches. In part, opposing pathomechanisms in RV and pulmonary vasculature, i.e., regarding apoptosis, angiogenesis and proliferation, complicate addressing RHF in PAH. Therapy effective for left heart failure is not applicable to RHF, e.g., inhibition of adrenoceptor signaling and of the renin-angiotensin system had no or only limited success. A number of experimental studies employing animal models for PAH or RV dysfunction or failure have identified beneficial effects of novel pharmacological agents, with most promising results obtained with modulators of metabolism and reactive oxygen species or inflammation, respectively. In addition, established PAH agents, in particular phosphodiesterase-5 inhibitors and soluble guanylate cyclase stimulators, may directly address RV integrity. Promising results are furthermore derived with microRNA (miRNA) and long non-coding RNA (lncRNA) blocking or mimetic strategies, which can target microvascular rarefaction, inflammation, metabolism or fibrotic and hypertrophic remodeling in the dysfunctional RV. Likewise, pre-clinical data demonstrate that cell-based therapies using stem or progenitor cells have beneficial effects on the RV, mainly by improving the microvascular system, however clinical success will largely depend on delivery routes. A particular option for PAH is targeted denervation of the pulmonary vasculature, given the sympathetic overdrive in PAH patients. Finally, acute and durable mechanical circulatory support are available for the right heart, which however has been tested mostly in RHF with concomitant left heart disease. Here, we aim to review current pharmacological, RNA- and cell-based therapeutic options and their potential to directly target the RV and to review available data for pulmonary artery denervation and mechanical circulatory support.

Current and future treatments of pulmonary arterial hypertension.

Therapeutic options for pulmonary arterial hypertension (PAH) have increased over the last decades. The advent of pharmacological therapies targeting the prostacyclin, endothelin, and NO pathways has significantly improved outcomes. However, for the vast majority of patients, PAH remains a life-limiting illness with no prospect of cure. PAH is characterised by pulmonary vascular remodelling. Current research focusses on targeting the underlying pathways of aberrant proliferation, migration, and apoptosis. Despite success in preclinical models, using a plethora of novel approaches targeting cellular GPCRs, ion channels, metabolism, epigenetics, growth factor receptors, transcription factors, and inflammation, successful transfer to human disease with positive outcomes in clinical trials is limited. This review provides an overview of novel targets addressed by clinical trials and gives an outlook on novel preclinical perspectives in PAH. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc.

MicroRNA-126 affects cell apoptosis, proliferation, cell cycle and modulates VEGF/TGF-β levels in pulmonary artery endothelial cells.

In the clinic, therapeutic options for pulmonary arterial hypertension are limited; therefore, investigating the therapeutic strategies and novel therapies is critical for pulmonary arterial hypertension (PAH) treatment. This study aimed to evaluate the role of miRNA-126 (miR-126) and its associated signaling pathways and specific mechanisms for the pathogenesis of PAH. The pulmonary artery endothelial cells (PAECs) were isolated and identified. The miR-126 mimic and miR-126 inhibitor were synthesized. LV-3-miR-126 mimic viral vector and LV-3-miR-126 inhibitor vector were established and infected into pulmonary artery endothelial cells. Expression of sprouty-related EVH1 domain-containing protein 1 (SPRED1), phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) and miR-126 were detected using Real-time PCR (RT-PCR). Cell apoptosis (Annexin V-PE/7-AAD) and proliferation (PKH26) were examined by using FACScan flow cytometry. Vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGF-β1) and TGF-β3 levels were evaluated using enzyme-linked immunosorbent assay (ELISA) kits. miR-126 inhibited the endothelial cells related to SPRED1 and PIK3R2 expression. Over-expression of miR-126 significantly inhibited the PAECs apoptosis compared to PAECs and blank LV-3 vector group (p<0.05). miR-126 significantly triggered the PAECs proliferation compared to PAECs and blank LV-3 vector group (p<0.05). In functional analysis, miR-126 mimic significantly increased the cells amounts of S phases compared to PAECs and blank LV-3 vector group (p<0.05). Pre-infection with miR-126 mimic significantly enhanced the levels of VEGF, TGF-β1, and TGF-β3 compared to PAECs and blank LV-3 vector group (p<0.05). miR-126 could affect cell apoptosis, proliferation, cell cycle, and modulate VEGF/TGF-β levels.

Udenafil as a Therapeutic Option for Pulmonary Arterial Hypertension

Udenafil as a Therapeutic Option for Pulmonary Arterial Hypertension

Identifying "super responders" in pulmonary arterial hypertension.

Pharmacotherapeutic options for pulmonary arterial hypertension (PAH) have increased dramatically in the last two decades and along with this have been substantial improvements in survival. Despite these advances, however, PAH remains a progressive and ultimately fatal disease for most patients and only epoprostenol has been shown to improve survival in a randomized control trial. Clinical observations of the heterogeneity of treatment response to different classes of medications across the phenotypically diverse PAH population has led to the identification of patients who derive significantly more benefit from certain medications than the population mean, the so-called “super responders.” This was first recognized among PAH patients with acute vasodilator response during invasive hemodynamic testing, a subset of whom have dramatically improved survival when treated with calcium channel blocker (CCB) therapy. Retrospective studies have now suggested a sex discrepancy in response to endothelin receptor antagonists (ERA) and phosphodiesterase inhibitors, and more recently a few studies have found genomic associations with response to CCBs and ERAs. With increasing availability of “omics” technologies, recognition of these “super responders,” combined with careful clinical and molecular phenotyping, will lead to advances in pharmacogenomics, precision medicine, and continued improvements in survival among PAH patients.

Pioglitazone alleviates cardiac and vascular remodelling and improves survival in monocrotaline induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a fatal disease with limited therapeutic options. Pathophysiological changes comprise obliterative vascular remodelling of small pulmonary arteries, elevated mean pulmonary arterial systolic pressure (PASP) due to elevated resistance of pulmonary vasculature, adverse right ventricular remodelling, and heart failure. Recent findings also indicate a role of increased inflammation and insulin resistance underlying the development of PAH. We hypothesized that treatment of this condition with the peroxisome proliferator-activated receptor-γ (PPARγ) activator pioglitazone, known to regulate the expression of different genes addressing insulin resistance, inflammatory changes, and vascular remodelling, could be a beneficial approach. PAH was induced in adult rats by a single subcutaneous injection of monocrotaline (MCT). Pioglitazone was administered for 2weeks starting 3weeks after MCT-injection. At day 35, hemodynamics, organ weights, and -indices were measured. We performed morphological and molecular characterization of the pulmonary vasculature, including analysis of the degree of muscularization, proliferation rates, and medial wall thickness of the small pulmonary arteries. Furthermore, markers of cardiac injury, collagen content, and cardiomyocyte size were analyzed. Survival rates were monitored throughout the experimental period. Pioglitazone treatment improved survival, reduced PASP, muscularization of small pulmonary arteries, and medial wall thickness. Further, MCT-induced right ventricular hypertrophy and fibrosis were attenuated. This was accompanied with reduced cardiac expression of brain natriuretic peptide, as well as decreased cardiomyocyte size. Finally, pulmonary macrophage content and osteopontin gene expression were attenuated. Based on the beneficial impact of pioglitazone, activation of PPARγ might be a promising treatment option in PAH.

The heart and pulmonary arterial hypertension in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by vasculopathy and progressive fibrosis of the skin and visceral organs (gastrointestinal tract, heart, kidneys and lungs). Although the prevalence is low, SSc is a disease with high morbidity and mortality. Since pulmonary arterial hypertension (PAH) associated with SSc (SSc-PAH) and clinically evident cardiac involvement is associated with increased mortality, the cardiac complications and PAH in SSc are reviewed. Both diffuse cutaneous (DcSSc) and limited cutaneous (LcSSc) subgroups are at risk for cardiac involvement and SSc-PAH. Cardiac involvement can be divided in pericardial involvement, myocardial involvement and rhythm disturbances and mostly occurs asymptomatically. However, when symptomatic, it is associated with a poor prognosis. Screening for asymptomatic cardiac involvement should be considered in SSc in order to initiate treatment in an early stage. However, there are no randomized controlled trials on treatment options for cardiac involvement in SSc. SSc-PAH is a devastating complication of SSc, which can develop early in DcSSc and LcSSc. Screening for PAH should be performed since screening leads to earlier diagnosis and earlier treatment is associated with a better prognosis. Today, screening is performed by clinical judgement and echocardiography. Recently the DETECT algorithm, a 2-step screening algorithm is proposed in a SSc-subgroup at increased risk for PAH, but further validation is needed. Despite current treatment options with prostacyclins, endothelin-1 receptor antagonists and phosphodiesterase type-5 inhibitors, mortality remains high. Several promising new treatment options for PAH are evaluated in phase II and III clinical trials.

Towards new targets for the treatment of pulmonary arterial hypertension : Importance of cell-cell communications

Pulmonary arterial hypertension (PAH) is a disorder in which mechanical obstruction of the pulmonary vascular bed is largely responsible for the rise in mean pulmonary arterial pressure (mPAP), resulting in a progressive functional decline despite current available therapeutic options. There are multiple mechanisms predisposing to and/or promoting the aberrant pulmonary vascular remodeling in PAH, and these involve not only altered crosstalk between cells within the vascular wall but also sustained inflammation and dysimmunity, cell accumulation in the vascular wall and excessive activation of some growth factor-stimulated signaling pathways, in addition to the interaction of systemic hormones, local growth factors, cytokines, and transcription factors. Heterozygous germline mutations in the bone morphogenetic protein receptor, type-2 (BMPR2) gene, a gene encoding a receptor for the transforming growth factor (TGF)-β superfamily, can predispose to the disease. Although the spectrum of therapeutic options for PAH has expanded in the last 20 years, available therapies remain essentially palliative. Over the past decade, however, a better understanding of key regulators of this irreversible remodeling of the pulmonary vasculature has been obtained. New and more effective approaches are likely to emerge. The present article profiles the innovative research into novel pathways and therapeutic targets that may lead to the development of targeted agents in PAH.

Inhibition of FGFR Signaling With PD173074 Ameliorates Monocrotaline-induced Pulmonary Arterial Hypertension and Rescues BMPR-II Expression.

Numerous studies have demonstrated that fibroblast growth factor-2 (FGF-2) signaling may play a pivotal role in the development of pulmonary arterial hypertension (PAH). Excessive endothelial FGF-2 contributes to smooth muscle hyperplasia and disease progression. PD173074 is a potent FGF receptor 1 (FGFR-1) inhibitor that displays high activity and selectivity. The aim of this study was to investigate the effects of PD173074 on monocrotaline-induced PAH. We also evaluated whether FGFR-1 inhibition could attenuate bone morphogenetic protein type II receptor (BMPR-II) downregulation in the monocrotaline model. PAH model was established by a single intraperitoneal injection of monocrotaline. And then a daily intraperitoneal injection of PD173074 (20 mg/kg) was administered from day 14 to day 28. Hemodynamic parameters, right ventricular hypertrophy index and morphometry were evaluated at day 28. Western blot and immunohistochemical analyses were used to determine the expression of FGF-2 and bone morphogenetic protein signaling in the lung tissue. The expression of FGF-2 and FGFR-1 was upregulated in lung tissue after monocrotaline injection and it was accompanied by hemodynamic changes and pulmonary vascular remodeling. PD173074 treatment ameliorated PAH and vascular remodeling. It decreased ERK1/2 activation and rescued total Akt expression, leading to a reduction in both proliferation and apoptosis in the lung. Besides, PD173074 rescued the expression of BMPR-II and p-Smad 1/5/8. These results suggest that PD173074 can alleviate monocrotaline-induced pulmonary arterial hypertension and it may be a useful option for PAH. Our data also suggest a role of FGF-2/bone morphogenetic protein signaling interaction in PAH.

Commentary: The sphingosine kinase 1/sphingosine-1-phosphate pathway in pulmonary arterial hypertension.

Commentary: The sphingosine kinase 1/sphingosine-1-phosphate pathway in pulmonary arterial hypertension.

Efficacy and Safety of Long-Term Imatinib Therapy for Pulmonary Arterial Hypertension

Background: Antiproliferative strategies have emerged as a potential therapeutic option for pulmonary arterial hypertension (PAH). Objective: To evaluate the long-term efficacy and safety of imatinib. Methods: This is an observational study of 15 patients with idiopathic PAH (n = 13) or PAH associated with connective tissue disease (n = 2) treated off-label with imatinib 400 mg daily. Pulmonary hypertension-specific therapy was established in all patients (triple therapy in 10, dual therapy in 3, and monotherapy in 2 patients). Results: After 6 months, improvement in hemodynamics (p < 0.01), functional class (p = 0.035), and quality of life (p = 0.005) was observed. After a median follow-up of 37 months, there was a sustained improvement in functional class (p = 0.032), quality of life (p = 0.019), and echocardiographic parameters of right ventricular function (p < 0.05). Three patients (20%) presented with completely normal echocardiography, absent tricuspid regurgitation, and normal pro-brain natriuretic peptide levels, indicative of ‘hemodynamic remission'. Of note, however, only 1 case was assessed by invasive hemodynamics. The overall 1- and 3-year survival was 100 and 90%, respectively. Two patients experienced a subdural hematoma (SDH), which in both cases resolved without sequelae. After careful consultation of the potential risks and benefits, all patients as well as a safety cohort of 9 subsequent cases decided to continue the imatinib therapy. After adjusting the target international normalized ratio (INR) to around 2.0, no further cases of SDH occurred during 50 patient-years. Conclusions: Long-term treatment with imatinib may improve the functional class and quality of life. Single cases might even attain hemodynamic remission. The occurrence of 5% SDH per patient-years is concerning. However, adjusting the INR to around 2.0 might obviate this complication.

Perspectives on oral pulmonary hypertension therapies recently approved by the U.S. Food and Drug Administration.

In the past 18 months, the U.S. Food and Drug Administration approved macitentan, riociguat, and treprostinil as oral agents for the treatment of pulmonary arterial hypertension (PAH); riociguat also became the first agent approved for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH). These new agents are welcome additional therapeutic options for PAH and CTEPH. However, their use can be complicated by potential drug interactions, adverse effects, dosing complexity, and cost. Macitentan, the newest endothelin receptor antagonist, showed significant benefits in a long-term event-driven trial of morbidity and mortality. Dosed once daily and with minimal liver toxicity, it has potential drug interactions with potent CYP 3A4 inhibitors and inducers, and can decrease hemoglobin levels. Riociguat is approved for PAH and clinically inoperable CTEPH to improve exercise capacity and functional status. Riociguat requires dose titration beginning with 1 mg up to 2.5 mg three times a day, as tolerated, and should be used with caution in patients with underlying risk factors for systemic hypotension. Oral treprostinil, approved to improve exercise capacity in PAH, is associated with gastrointestinal side effects and headaches that are often dose limiting. Doses can begin with 0.125 mg or 0.25 mg twice a day with gradual increases on up to a weekly basis, as tolerated. Thrice daily dosing and administration with a meal can improve tolerance. These newer agents represent advances, but their specific roles in relation to pre-existing therapies are undergoing further evaluation. Therefore, close collaboration with clinicians at centers with therapeutic expertise is highly recommended to optimize patient outcomes.

80: Treatment of Pulmonary Arterial Hypertension Using Sildenafil in Neonates with Bronchopulmonary Dysplasia

Sildenafil citrate, a phosphodiesterase-5-inhibitor, is a controversial treatment option for pulmonary arterial hypertension (PHT), a significant complication of bronchopulmonary dysplasia (BPD).There is scarce data in premature infants. Evaluate the use of sildenafil citrate in infants with BPD complicated by PHT. Retrospective cohort study in a level 3 NICU. All medical records of premature infants with PHT secondary to BPD treated with sildenafil citrate between January 2009 and May 2013 were reviewed. Primary outcomes were: Clinical response with 20% decrease in: respiratory support score or FiO2 requirements Echocardiographic response with decrease in tricuspid regurgitation gradient (at least 20%) or septal flattening (at least one degree) Twenty three infants (61% male) with a median (IQR) gestational age of 26 weeks (23 to 30weeks) and birth weight of 710 g (480 g to 1170 g) were included. Antenatal data is marked by presence of chorioamnionitis (17%), oligohydramnios (22%), intrauterine growth retardation (39%) and premature rupture of membranes (39%). Neonatal course included: confirmed sepsis (48%), grade 2 or more necrotizing enterocolitis (32%), stage 3 retinopathy of prematurity (ROP) (56%) and patent ductus arteriosus (78%). Pharmacologic data, benefits and side effects are represented in the table. Sildenafil citrate treatment for patients with PHT

Palosuran Treatment Effective as Bosentan in the Treatment Model of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a progressive and fatal disorder that any valuable advance in the management of diseases has crucial importance. The present study aimed to compare the Endothelin1 (ET1) inhibitor bosentan which is regarded as standard therapy with different dose regimens of palosuran which is urotensin-II (UII) inhibitor and explore the discrepancy for mean pulmonary arterial pressure (mPAP), UII, ET1 levels, and pulmonary vascular pathology. Seventy rats were randomly divided into seven groups of ten animals each: group 1 (control group) received the vehicle subcutaneously, instead of monocrotaline (MCT) and vehicle; group 2 (MCT group) received subcutaneous MCT and vehicle; and group 3 (MCT + palosuran 30mg) received subcutaneous MCT and palosuran. Other groups consist of group 4 (MCT + palosuran 100mg), group 5 (MCT + bosentan 30mg), group 6 (MCT + bosentan 100mg), and group 7 (combination therapy). Serum ET1, UII, mPAP levels, and pulmonary arteriolar pathology of different diameter vessels of all groups have been measured and recorded. The ET1 and UII levels of untreated rats (group 2) were significantly higher than the other groups (p < 0.05). Moreover, mPAP levels of group 2 were significantly higher than the other groups (p = 0.001). Finally, 50-125-μm diameter of arteriole wall thickness was found to be significantly thicker in monocrotaline group compared to groups 4 and 6 (p < 0.001). Statistical differences of wall thickness/diameter ratios of arteries and arterioles larger than 125 was found to be significant between group 5, group 6, and the control group (p < 0.001). UII inhibitor is at least as effective as standard therapy bosentan. Findings of this study consolidate that palosuran could be a new future promising therapeutic option in PAH.