Clinical Outcomes of Pulmonary Arterial Hypertension in Carriers ofBMPR2Mutation

Consistent Safety and Efficacy of Sotatercept for Pulmonary Arterial Hypertension in BMPR2 Mutation Carriers and Noncarriers: A Planned Analysis of a Phase II, Double-Blind, Placebo-controlled Clinical Trial (PULSAR)

Rationale: It is unclear whether carriers of pathogenic variants in PAH-associated genes have a distinct response to PAH treatment. Objectives: To evaluate the effect of genetic variant status on the efficacy of sotatercept and the effect of sotatercept treatment on biomarkers in pulmonary arterial hypertension. Methods: PULSAR (A Study of Sotatercept for the Treatment of Pulmonary Arterial Hypertension; NCT03496207) was a phase II, randomized controlled study of sotatercept versus placebo added to background therapy for pulmonary arterial hypertension. Participants underwent DNA sequencing at baseline to detect genetic variants in disease-associated genes (ACVRL1, BMPR2, CAV1, EIF2AK4, ENG, KCNA3, KCNK3, and SMAD9). Safety (adverse events) and efficacy (pulmonary vascular resistance, 6-min-walk distance) were assessed by variant status and treatment at 24 weeks. Serum concentrations of BMPR2 mRNA and N-terminal prohormone B-type natriuretic peptide were assessed at baseline and 24 weeks by treatment and variant status. Analysis of covariance was used to compare the change from baseline by treatment and variant status. Measurements and Main Results: Among 76 participants included, pathogenic variants were detected in 25 (23 BMPR2, 2 other), and 51 had no variants or variants of uncertain significance. BMPR2 mutation carriers were younger and more frequently on triple therapy but had less severe clinical characteristics at baseline. Changes at 24 weeks in pulmonary vascular resistance and 6-minute-walk distance did not differ by variant status. BMPR2 gene expression varied less than twofold from baseline over time, irrespective of treatment or variant status. The adverse event profile was generally consistent with that seen in the parent PULSAR study. Conclusions: These results suggest consistent safety and clinical efficacy of sotatercept for treatment of pulmonary arterial hypertension, irrespective of BMPR2 variant status.

Therapeutic targets for pulmonary arterial hypertension: insights into the emerging landscape

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive, life-threatening disease driven by vascular remodeling, right ventricular (RV) dysfunction, and metabolic and inflammatory dysregulation. Current therapies primarily target vasodilation to relieve symptoms but do not reverse disease progression. The recent approval of sotatercept, which modulates BMP/TGF-β signaling, marks a shift toward anti-remodeling therapies. Building on this, recent preclinical advances have identified promising therapeutic targets and potentially disease-modifying treatments.

AREAS COVERED

This review synthesizes the evolving preclinical landscape of emerging PAH therapeutic targets and drugs, highlighting innovative approaches aimed at addressing the underlying mechanisms of disease progression. Additionally, we discuss novel therapeutic strategies under development.

EXPERT OPINION

Recent advances in PAH research have identified novel therapeutic targets beyond vasodilators, including modulation of BMP/TGF-β signaling, metabolic programs, epigenetics, cancer-related signaling, the extracellular matrix, and immune pathways, among others. Sotatercept represents a significant advance in therapies that go beyond vasodilation, and long-term safety, efficacy, and durability are being assessed. Future treatment strategies will focus on precision approaches, noninvasive technologies, and regenerative biology to improve outcomes and reverse vascular remodeling.

Haemodynamic spectrum in heritable pulmonary arterial hypertension: a continuum from pre-capillary to combined pulmonary hypertension-case series

Background

Heritable pulmonary arterial hypertension (PAH) is a rare form of pre-capillary pulmonary hypertension that typically affects young patients. With increased survival and subsequent ageing of these patients, newly acquired cardiovascular conditions may influence the pulmonary haemodynamic profile and impact management.

Case summary

We report a case series of four patients with mutations in genes associated with PAH to illustrate the spectrum of pulmonary haemodynamics under the influence of superimposed acquired conditions. The first two cases involve patients with a long-standing diagnosis of heritable PAH and severe pre-capillary pulmonary hypertension, who developed overt left-sided diastolic dysfunction later in follow-up due to the acquisition of multiple cardiovascular comorbidities. The second two cases describe patients with a genetic pre-disposition to develop PAH and conditions that are risk factors for left heart disease, with mild elevation of resting pulmonary pressures, in whom exercise right heart catheterization unmasked occult left-sided diastolic dysfunction.

Discussion

Pulmonary haemodynamics are complex and dynamic over time, even in patients with or at risk of heritable PAH, when additional acquired cardiovascular conditions emerge. Correct phenotyping at diagnosis and during follow-up of patients at risk of heritable PAH, along with a clear understanding of the underlying pulmonary haemodynamic profile, is crucial for appropriate management.

Pulmonary hypertension in patients carrying FLNA loss-of-function variants

BACKGROUND

Pulmonary hypertension (PH) is an unusual complication of X-linked disease caused by loss-of-function (LOF) variants in the filamin A (FLNA) gene. Patients with FLNA LOF may also present dysmorphic facial features, aortic dilation, thrombocytopenia and periventricular nodular heterotopia (PVNH).

METHODS

We reported the clinical, functional, haemodynamic and radiological characteristics of patients with FLNA LOF variants and PH from the French PH Network.

RESULTS

Nine patients were identified with a female:male ratio of 8:1. PH was diagnosed at a median (range) age of 36 (0-69) years. Associated conditions included epilepsy (n=5), PVNH (n=7), valvular heart disease (n=8), congenital heart diseases (n=4), thrombocytopenia (n=4) and hyperlaxity (n=4). Right heart catheterisation confirmed moderate-to-severe pre-capillary PH with a median (range) mean pulmonary arterial pressure of 33 (22-49) mmHg and pulmonary vascular resistance of 4.7 (2.4-8.0) WU. The median (range) diffusing capacity of the lung for carbon monoxide corrected for haemoglobin was markedly decreased (48% (22-64%) of predicted values) and five patients had obstructive ventilatory disorder. High-resolution computed tomography showed heterogeneous parenchyma (n=8), emphysema (n=3), presence of a peripheral hyperclear band (n=3) and aortic ectasia (n=4). Pathological assessment available in one patient revealed significant remodelling of small pulmonary arteries, interstitial oedema and irregular alveoli shapes. During follow-up, three patients died, including two from right heart failure. No patient died from aortic rupture.

CONCLUSIONS

Pre-capillary PH, likely due to multiple mechanisms, may complicate the course of patients with FLNA LOF variants and may be the presenting symptom leading to diagnosis. The combination of PH with parenchymal involvement and extrapulmonary symptoms (epilepsy, congenital heart diseases, valvular and aortic involvement, and thrombocytopenia) should prompt genetic screening for FLNA.

Impact of BMPR2 mutation on the severity of pulmonary arterial hypertension: a systematic review and meta-analysis

OBJECTIVE

To evaluate the association between PAH severity in patients with and without BMPR2 mutation. Additionally, subgroup analyses were also performed to investigate whether differences existed among different ethnicities.

METHODS

A literature search of the PubMed-MEDLINE, EMBASE, Web of Science, Scopus, and Cochrane Central Register of Controlled Trials databases was conducted from inception through June, 2024, to identify eligible studies. Analyses were performed using Stata.

RESULTS

Seventeen nonrandomized studies comprising a total of 2,190 patients were included in the analysis. Among the hemodynamic variables, the mPAP (WMD = 6.41, 95% CI: 5.07 ~ 7.76, P = 0.000), PVR (WMD = 3.66, 95% CI: 2.79 ~ 4.53, P = 0.000), CI (WMD=-0.38, 95% CI: -0.45 ~ -0.32, P = 0.000), and CO (WMD=-0.60, 95% CI: -0.99 ~ -0.21, P = 0.003) were significantly different at diagnosis between patients with and without BMPR2 mutations. No significant differences were found in RAP and PAWP. Furthermore, subgroup analysis was conducted on data showing significant differences, revealing no significant differences in mPAP and PVR between Asian and Caucasian patients with BMPR2 mutations. However, significant differences in CI and CO were observed between these two ethnic groups, with CI and CO in Caucasians being more affected by BMPR2 mutations and decreasing more than in Asians.

CONCLUSION

There is a statistically significant difference in the hemodynamic variables of PAH between BMPR2 mutation carriers and non-carriers, highlighting the mutation's impact on PAH severity. This influence is not associated with ethnicity in mPAP and PVR; however, it is associated with ethnicity in CI and CO, with Caucasians being more affected by BMPR2 mutations than Asians. This suggests that Caucasians may be more sensitive to BMPR2 mutations. These findings underscore the necessity of genetic testing for PAH patients, particularly among the Caucasian population. Given the poorer clinical phenotype and prognosis of BMPR2 mutation carriers, closer follow-up may be required.

Gaps in evidence in the management of patients with intermediate-risk pulmonary arterial hypertension: Considerations following the ESC/ERS 2022 guidelines

A comprehensive evaluation of risk, using multiple indices, is necessary to provide reliable prognostic information and guide therapy in pulmonary arterial hypertension (PAH). The current ESC/ERS guidelines suggest using a three-strata model for incident (newly diagnosed) patients and a four-strata model for prevalent patients with PAH. The four-strata model serves as a fundamental risk-stratification tool and relies on a minimal dataset of indicators that must be considered during follow-up. Nevertheless, there are still areas of vagueness and ambiguity when classifying and managing patients in the intermediate-risk category. For these patients, considerations should include right heart imaging, hemodynamics, as well as individual factors such as age, sex, genetic profile, disease type, comorbidities, and kidney function. The aim of this report is to present case studies, with a specific focus on patients ultimately classified as intermediate risk. We aim to emphasize the challenges and complexities encountered in the realms of diagnosis, classification, and treatment for these particular patients.

Hemodynamic and Clinical Profiles of Pulmonary Arterial Hypertension Patients with GDF2 and BMPR2 Variants

Asians have a higher carrier rate of pulmonary arterial hypertension (PAH)-related genetic variants than Caucasians do. This study aimed to identify PAH-related genetic variants using whole exome sequencing (WES) in Asian idiopathic and heritable PAH cohorts. A WES library was constructed, and candidate variants were further validated by polymerase chain reaction and Sanger sequencing in the PAH cohort. In a total of 69 patients, the highest incidence of variants was found in the BMPR2, ATP13A3, and GDF2 genes. Regarding the BMPR2 gene variants, there were two nonsense variants (c.994C>T, p. Arg332*; c.1750C>T, p. Arg584*), one missense variant (c.1478C>T, p. Thr493Ile), and one novel in-frame deletion variant (c.877_888del, p. Leu293_Ser296del). Regarding the GDF2 variants, there was one likely pathogenic nonsense variant (c.259C>T, p. Gln87*) and two missense variants (c.1207G>A, p. Val403Ile; c.38T>C, p. Leu13Pro). The BMPR2 and GDF2 variant subgroups had worse hemodynamics. Moreover, the GDF2 variant patients were younger and had a significantly lower GDF2 value (135.6 ± 36.2 pg/mL, p = 0.002) in comparison to the value in the non-BMPR2/non-GDF2 mutant group (267.8 ± 185.8 pg/mL). The BMPR2 variant carriers had worse hemodynamics compared to the patients with the non-BMPR2/non-GDF2 mutant group. Moreover, there was a significantly lower GDF2 value in the GDF2 variant carriers compared to the control group. GDF2 may be a protective or corrected modifier in certain genetic backgrounds.

Heritable Pulmonary Arterial Hypertension in a Patient With Empty Sella Syndrome: A Case Report

Pulmonary arterial hypertension (PAH) is a progressive disease with multiple contributing factors. Genetics, epigenetics, hormonal, and immune factors all contribute to the development and progression of the disease. A number of endocrine disorders and metabolic syndromes are being studied for their potential role in the development of PAH. We report to you a case of a 32-year-old female with a rare presentation of a non-BMPR2 mutation heritable PAH complicated with empty sella syndrome and panhypopituitarism.

Resistin-like Molecule α and Pulmonary Vascular Remodeling: A Multi-Strain Murine Model of Antigen and Urban Ambient Particulate Matter Co-Exposure

Pulmonary hypertension (PH) has a high mortality and few treatment options. Adaptive immune mediators of PH in mice challenged with antigen/particulate matter (antigen/PM) has been the focus of our prior work. We identified key roles of type-2- and type-17 responses in C57BL/6 mice. Here, we focused on type-2-response-related cytokines, specifically resistin-like molecule (RELM)α, a critical mediator of hypoxia-induced PH. Because of strain differences in the immune responses to type 2 stimuli, we compared C57BL/6J and BALB/c mice. A model of intraperitoneal antigen sensitization with subsequent, intranasal challenges with antigen/PM (ovalbumin and urban ambient PM2.5) or saline was used in C57BL/6 and BALB/c wild-type or RELMα-/- mice. Vascular remodeling was assessed with histology; right ventricular (RV) pressure, RV weights and cytokines were quantified. Upon challenge with antigen/PM, both C57BL/6 and BALB/c mice developed pulmonary vascular remodeling; these changes were much more prominent in the C57BL/6 strain. Compared to wild-type mice, RELMα-/- had significantly reduced pulmonary vascular remodeling in BALB/c, but not in C57BL/6 mice. RV weights, RV IL-33 and RV IL-33-receptor were significantly increased in BALB/c wild-type mice, but not in BALB/c-RELMα-/- or in C57BL/6-wild-type or C57BL/6-RELMα-/- mice in response to antigen/PM2.5. RV systolic pressures (RVSP) were higher in BALB/c compared to C57BL/6J mice, and RELMα-/- mice were not different from their respective wild-type controls. The RELMα-/- animals demonstrated significantly decreased expression of RELMβ and RELMγ, which makes these mice comparable to a situation where human RELMβ levels would be significantly modified, as only humans have this single RELM molecule. In BALB/c mice, RELMα was a key contributor to pulmonary vascular remodeling, increase in RV weight and RV cytokine responses induced by exposure to antigen/PM2.5, highlighting the significance of the genetic background for the biological role of RELMα.

The cascade screening in heritable forms of pulmonary arterial hypertension

Heritable pulmonary artery hypertension (HPAH) is an increasingly recognized type of pulmonary arterial hypertension, in both pediatric and adult population. Intrinsic to hereditary disease, screening for genetic mutations within families is an important component of diagnosis and understanding burden of disease. Recently, consensus guidelines are published for genetic screening in PAH. These guidelines include recommendations for screening at diagnosis, noting individuals with presumed PAH due to familial, or idiopathic etiologies. Cascade genetic testing is specifically recommended as a testing paradigm to screen relatives for detection of mutation carriers, who may be asymptomatic. Without targeted genetic testing, familial mutation carriers may only come to attention when pulmonary vascular disease burden is high enough to cause symptoms, suggesting more advanced disease. Here, we present our collective experience with HPAH in five distinct families, specifically to report on the clinical courses of patients who were diagnosed with genetic mutation at diagnosis versus those who were offered genetic screening. In three families, asymptomatic mutation carriers were identified and monitored for clinical worsening. In two families, screening was not done and affected family members presented with advanced disease.

Imaging Features in BMPR2 Mutation-associated Pulmonary Arterial Hypertension

Background Germline mutation in the BMPR2 gene is common in patients with pulmonary arterial hypertension (PAH). However, its association with imaging findings in these patients is, to the knowledge of the authors, unknown. Purpose To characterize distinctive pulmonary vascular abnormalities at CT and pulmonary artery angiography in patients with and without BMPR2 mutation. Materials and Methods In this retrospective study, chest CT scans, pulmonary artery angiograms, and genetic test data were acquired for patients diagnosed with idiopathic PAH (IPAH) or heritable PAH (HPAH) between January 2010 and December 2021. Perivascular halo, neovascularity, centrilobular ground-glass opacity (GGO), and panlobular GGO were evaluated at CT and graded on a four-point severity scale by four independent readers. Clinical characteristics and imaging features between patients with BMPR2 mutation and noncarriers were analyzed using the Kendall rank-order coefficient and the Kruskal-Wallis test. Results This study included 82 patients with BMPR2 mutation (mean age, 38 years ± 15 [SD]; 34 men; 72 patients with IPAH and 10 patients with HPAH) and 193 patients without the mutation, all with IPAH (mean age, 41 years ± 15; 53 men). A total of 115 patients (42%; 115 of 275) had neovascularity, and 56 patients (20%; 56 of 275) had perivascular halo at CT, and so-called frost crystals were observed on pulmonary artery angiograms in 14 of 53 (26%) patients. Compared with patients without BMPR2 mutation, patients with BMPR2 mutation more frequently showed two distinctive radiographic manifestations, perivascular halo and neovascularity (38% [31 of 82] vs 13% [25 of 193] in perivascular halo [P < .001] and 60% [49 of 82] vs 34% [66 of 193] in neovascularity [P < .001], respectively). "Frost crystals" were more frequent in patients with BMPR2 mutation compared with noncarriers (53% [10 of 19] vs 12% [four of 34]; P < .01). Severe perivascular halo frequently coexisted with severe neovascularity in patients with BMPR2 mutation. Conclusion Patients with PAH with BMPR2 mutation showed distinctive features at CT, specifically perivascular halo and neovascularity. This suggested a link between the genetic, pulmonary, and systemic manifestations that underly the pathogenesis of PAH. © RSNA, 2023 Supplemental material is available for this article.

Decreased circulating microRNA-21 and microRNA-143 are associated to pulmonary hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by maladaptation of pulmonary vasculature which is leading to right ventricular hypertrophy and heart failure. miRNAs play a crucial role in the regulation of many diseases such as viral infection, cancer, cardiovascular diseases, and pulmonary hypertension (PH). In this study, we aimed to investigate the expression pattern of eight human plasma miRNAs (hsa-miR-21-3p, hsa-miR-143- 3p, hsa-miR-138-5p, hsa-miR-145-3p, hsa-miR-190a, hsa-miR-204-3p, hsamiR-206, hsa-miR-210-3p) in mild-to-severe PH patients and healthy controls.

METHODS

: miRNAs were extracted from the peripheral plasma of the PH patients (n: 44) and healthy individuals (n: 30) by using the miRNA Isolation Kit. cDNA was synthesized using All in-One First strand cDNA Synthesis Kit. Expression of the human plasma hsa-miR- 21-3p, hsa-miR-143-3p, hsa-miR-138-5p, hsa-miR-145-3p, hsa-miR-190a, hsa-miR-204- 3p, hsa-miR-206, hsa-miR210-3p, and miRNAs were analyzed by qRT-PCR.

RESULTS

According to our results, in PH patients hsa-miR-21-3p and hsa-miR-143-3p expression levels were decreased by 4.7 and 2.3 times, respectively. No significant changes were detected in hsa-miR-138-5p, hsa-miR-145-3p, hsa-miR-190a, hsa-miR-204-3p, hsamiR-206, and hsa-miR-210-3p expression levels between PH and control groups. In addition, considering the severity of the disease, it was observed that the decrease in miR-138, miR-143, miR-145, miR-190, mir-204, mir-206 and miR-208 expressions was significant in patients with severe PH.

DISCUSSION

: In the early diagnosis of PAH, hsa-miR-21-3p and especially hsa-miR-143-3p in peripheral plasma can be considered as potential biomarkers.

An emerging phenotype of pulmonary arterial hypertension patients carrying SOX17 variants

BACKGROUND

The phenotype of pulmonary arterial hypertension (PAH) patients carrying SOX17 pathogenic variants remains mostly unknown.

METHODS

We report the genetic analysis findings, characteristics and outcomes of patients with heritable PAH carrying SOX17 variants from the French Pulmonary Hypertension Network.

RESULTS

20 patients and eight unaffected relatives were identified. The median (range) age at diagnosis was 17 (2-53) years, with a female:male ratio of 1.5. At diagnosis, most of the patients (74%) were in New York Heart Association Functional Class III or IV with severe haemodynamic compromise, including a median pulmonary vascular resistance of 14.0 (4.2-31.5) WU. An associated congenital heart disease (CHD) was found in seven PAH patients (35%). Patients with CHD-associated PAH were significantly younger at diagnosis than PAH patients without CHD. Four patients (20%) suffered from recurrent haemoptysis requiring repeated arterial embolisations. 13 out of 16 patients (81%) for whom imaging was available displayed chest computed tomography abnormalities, including dilated, tortuous pulmonary vessels, ground-glass opacities as well as anomalies of the bronchial and nonbronchial arteries. After a median (range) follow-up of 47 (1-591) months, 10 patients underwent lung transplantation and one patient benefited from a heart-lung transplantation due to associated CHD. Histopathological analysis of lung explants showed a congested lung architecture with severe pulmonary arterial remodelling, subpleural vessel dilation and numerous haemorrhagic foci.

CONCLUSIONS

PAH due to SOX17 pathogenic variants is a severe phenotype, frequently associated with CHD, haemoptysis and radiological abnormalities. Pathological assessment reveals severe pulmonary arterial remodelling and malformations affecting pulmonary vessels and thoracic systemic arteries.

Whole Exome Sequencing of Patients With Heritable and Idiopathic Pulmonary Arterial Hypertension in Central Taiwan

Background

Genetic variants could be identified in subjects with idiopathic and heritable pulmonary arterial hypertension (PAH). The 6th World Symposium on Pulmonary Hypertension (WSPH) provided a list of genes with evidence of association with PAH. However, reports using whole exome sequencing (WES) from southeastern Asian PAH cohorts were scarce.

Methods

Subjects with idiopathic and heritable PAH (N = 45) from two medical centers in central Taiwan were screened for PAH related gene variants. The genomic DNA was prepared from peripheral blood lymphocytes. We performed WES for all patients enrolled in this study. All identified gene variants were validated by polymerase-chain reaction and Sanger sequencing. The clinical and hemodynamic data were compared between bone morphogenetic protein receptor type-2 (BMPR2) gene variants carriers vs. non-carriers.

Results

Eight patients (8/45 = 17.8%) was identified carrying BMPR2 gene variants and 8 patients (8/45 = 17.8%) had other WSPH-listed PAH-related gene variants (1 with ACVRL1, 1 with ENG, 1 with SMAD9, 1 with SMAD1, 1 with ATP13A3 and 3 with AQP1). In addition, a total of 14 non-WSPH-listed PAH-related genetic variant sites (ABCC8, NOTCH1, NOTCH2, NOTCH3, JAG1, BMP10, GGCX, FBLN2, ABCA3 and PTGIS) were found in this PAH cohort. Subjects carrying BMPR2 gene variant (N = 8) were younger at diagnosis of PAH (30 ± 11 vs 49 ± 13 years, p = 0.001) than the non-carrier group (N = 37). BMPR2 variant carriers had a trend toward having higher mean pulmonary arterial pressure (PAP) (61 ± 19 vs. 51 ± 13 mmHg, p = 0.076) than the non-carriers upon initial diagnosis. Pulmonary vascular resistance, right atrial pressure, cardiac output, as well as functional class were similar between BMPR2 variant carriers and non-carriers at initial diagnosis.

Conclusions

We identified 17.8% of patients with BMPR2 gene variants and 17.8% subjects with other 6th WSPH-listed PAH-related gene variants in a Taiwanese idiopathic and heritable PAH cohort. PAH patients carrying BMPR2 variants presented at a younger age with a trend toward having higher mean PAP at initial diagnosis.

New Mutations and Pathogenesis of Pulmonary Hypertension: Progress and Puzzles in Disease Pathogenesis

Pulmonary arterial hypertension (PAH) is a complex multifactorial disease with poor prognosis characterized by functional and structural alterations of the pulmonary circulation causing marked increase in pulmonary vascular resistance, ultimately leading to right heart failure and death. Mutations in the gene encoding BMPRII-a receptor for the TGF-β (transforming growth factor-beta) superfamily-account for over 70% of families with PAH and ≈20% of sporadic cases. In recent years, however, less common or rare mutations in other genes have been identified. This review will consider how these newly discovered PAH genes could help to provide a better understanding of the molecular and cellular bases of the maintenance of the pulmonary vascular integrity, as well as their role in the PAH pathogenesis underlying occlusion of arterioles in the lung. We will also discuss how insights into the genetic contributions of these new PAH-related genes may open up new therapeutic targets for this, currently incurable, cardiopulmonary disorder.

Diagnosis and Treatment of Pulmonary Arterial Hypertension: A Review

IMPORTANCE

Pulmonary arterial hypertension (PAH) is a subtype of pulmonary hypertension (PH), characterized by pulmonary arterial remodeling. The prevalence of PAH is approximately 10.6 cases per 1 million adults in the US. Untreated, PAH progresses to right heart failure and death.

OBSERVATIONS

Pulmonary hypertension is defined by a mean pulmonary artery pressure greater than 20 mm Hg and is classified into 5 clinical groups based on etiology, pathophysiology, and treatment. Pulmonary arterial hypertension is 1 of the 5 groups of PH and is hemodynamically defined by right heart catheterization demonstrating a mean pulmonary artery pressure greater than 20 mm Hg, a pulmonary artery wedge pressure of 15 mm Hg or lower, and a pulmonary vascular resistance of 3 Wood units or greater. Pulmonary arterial hypertension is further divided into subgroups based on underlying etiology, consisting of idiopathic PAH, heritable PAH, drug- and toxin-associated PAH, pulmonary veno-occlusive disease, PAH in long-term responders to calcium channel blockers, and persistent PH of the newborn, as well as PAH associated with other medical conditions including connective tissue disease, HIV, and congenital heart disease. Early presenting symptoms are nonspecific and typically consist of dyspnea on exertion and fatigue. Currently approved therapy for PAH consists of drugs that enhance the nitric oxide-cyclic guanosine monophosphate biological pathway (sildenafil, tadalafil, or riociguat), prostacyclin pathway agonists (epoprostenol or treprostinil), and endothelin pathway antagonists (bosentan and ambrisentan). With these PAH-specific therapies, 5-year survival has improved from 34% in 1991 to more than 60% in 2015. Current treatment consists of combination drug therapy that targets more than 1 biological pathway, such as the nitric oxide-cyclic guanosine monophosphate and endothelin pathways (eg, ambrisentan and tadalafil), and has shown demonstrable improvement in morbidity and mortality compared with the previous conventional single-pathway targeted monotherapy.

CONCLUSIONS AND RELEVANCE

Pulmonary arterial hypertension affects an estimated 10.6 per 1 million adults in the US and, without treatment, typically progresses to right heart failure and death. First-line therapy with drug combinations that target multiple biological pathways are associated with improved survival.

TGF‐β receptor mutations and clinical prognosis in Chinese Pediatric Patients with idiopathic/hereditary Pulmonary Arterial Hypertension

The relationship between clinical prognosis and transforming growth factor‐β (TGF‐β) receptor mutations in Chinese pediatric patients with idiopathic/hereditary pulmonary arterial hypertension (IPAH/HPAH) remains unclear. We retrospectively studied the clinical characteristics and outcomes of pediatric patients with IPAH/HPAH who visited our Hospital from September 2008 to December 2020. One hundred and five pediatric patients with IPAH/HPAH were included, 46 of whom carried TGF‐β receptor mutations with a mean age at diagnosis of 82.8 ± 52.7 months, and 67 of them underwent right cardiac catheterization examinations and acute vasodilator testing. The result showed that mutation carriers demonstrated higher pulmonary vascular resistance (p = 0.012), higher right atrial pressure (p = 0.026), and lower cardiac index (p = 0.003). The 1‐, 2‐, and 3‐year survival rates of mutation carriers were 79.4%, 61.5% and 55.6%, respectively, compared with 96.6%, 91.1%, and 85.4% for nonmutation carriers (p = 0.0001). The prognosis of mutation carriers was significantly worse than that of nonmutation carriers. TGF‐β receptor gene mutation is an independent risk factor for death (p = 0.049, odd raito = 3.809, 95% confidence interval 1.006−14.429). In conclusion, TGF‐β receptor mutation is an important genetic factor for the onset of IPAH/PAH in Chinese pediatric patients. Those who carrying TGF‐β receptor mutations have a poor clinical prognosis. Therefore, TGF‐β receptor gene screening for pediatric patients with PAH and more aggressive treatment for mutation carriers are recommended.

CRISPR-mediated Bmpr2 point mutation exacerbates late pulmonary vasculopathy and reduces survival in rats with experimental pulmonary hypertension

Background

Patients with pulmonary arterial hypertension (PAH) carrying bone morphogenetic protein receptor type 2 (Bmpr2) mutations present earlier with severe hemodynamic compromise and have poorer survival outcomes than those without mutation. The mechanism underlying the worsening clinical phenotype of PAH with Bmpr2 mutations has been largely unaddressed in rat models of pulmonary hypertension (PH) because of the difficulty in reproducing progressive PH in mice and genetic modification in rats. We tested whether a clinically-relevant Bmpr2 mutation affects the progressive features of monocrotaline (MCT) induced-PH in rats.

Methods

A monoallelic single nucleotide insertion in exon 1 of Bmpr2 (+/44insG) was generated in rats using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9, then PH, pulmonary vascular disease (PVD) and survival after MCT injection with or without a phosphodiesterase type 5 inhibitor, tadalafil, administration were assessed.

Results

The +/44insG rats had reduced BMPR2 signalling in the lungs compared with wild-type. PH and PVD assessed at 3-weeks after MCT injection were similar in wild-type and +/44insG rats. However, survival at 4-weeks after MCT injection was significantly reduced in +/44insG rats. Among the rats surviving at 4-weeks after MCT administration, +/44insG rats had increased weight ratio of right ventricle to left ventricle plus septum (RV/[LV + S]) and % medial wall thickness (MWT) in pulmonary arteries (PAs). Immunohistochemical analysis showed increased vessels with Ki67-positive cells in the lungs, decreased mature and increased immature smooth muscle cell phenotype markers in the PAs in +/44insG rats compared with wild-type at 3-weeks after MCT injection. Contraction of PA in response to prostaglandin-F2α and endothelin-1 were significantly reduced in the +/44insG rats. The +/44insG rats that had received tadalafil had a worse survival with a significant increase in RV/(LV + S), %MWT in distal PAs and RV myocardial fibrosis compared with wild-type.

Conclusions

The present study demonstrates that the Bmpr2 mutation promotes dedifferentiation of PA smooth muscle cells, late PVD and RV myocardial fibrosis and adversely impacts both the natural and post-treatment courses of MCT-PH in rats with significant effects only in the late stages and warrants preclinical studies using this new genetic model to optimize treatment outcomes of heritable PAH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02005-w.

Pulmonalarterielle Hypertonie bei Frauen

Die pulmonalarterielle Hypertonie (PAH) ist eine seltene Erkrankung mit vielen Untergruppen. Frauen sind wesentlich häufiger betroffen bei der „klassischen“ idiopathischen Form, der hereditären und bei der Kollagenose-assoziierten PAH. Es wird vermutet, dass der höhere Östrogenspiegel bei Frauen die Pathophysiologie mit Einengung der kleinen Pulmonalarteriolen als Ursache der PAH zumindest bei den Mutationsträgerinnen begünstigt. PAH-Patientinnen haben ähnliche Symptome wie betroffene Männer, sprechen aber möglicherweise anders auf gezielte PAH-Therapien an. Sie haben im Mittel ein längeres Überleben im Vergleich zu männlichen Patienten. In dieser Arbeit werden wir

Regulation of the Methylation and Expression Levels of the BMPR2 Gene by SIN3a as a Novel Therapeutic Mechanism in Pulmonary Arterial Hypertension

BACKGROUND

Epigenetic mechanisms are critical in the pathogenesis of pulmonary arterial hypertension (PAH). Previous studies have suggested that hypermethylation of the BMPR2 (bone morphogenetic protein receptor type 2) promoter is associated with BMPR2 downregulation and progression of PAH. Here, we investigated for the first time the role of SIN3a (switch-independent 3a), a transcriptional regulator, in the epigenetic mechanisms underlying hypermethylation of BMPR2 in the pathogenesis of PAH.

METHODS

We used lung samples from PAH patients and non-PAH controls, preclinical mouse and rat PAH models, and human pulmonary arterial smooth muscle cells. Expression of SIN3a was modulated using a lentiviral vector or a siRNA in vitro and a specific adeno-associated virus serotype 1 or a lentivirus encoding for human SIN3a in vivo.

RESULTS

SIN3a is a known transcriptional regulator; however, its role in cardiovascular diseases, especially PAH, is unknown. It is interesting that we detected a dysregulation of SIN3 expression in patients and in rodent models, which is strongly associated with decreased BMPR2 expression. SIN3a is known to regulate epigenetic changes. Therefore, we tested its role in the regulation of BMPR2 and found that BMPR2 is regulated by SIN3a. It is interesting that SIN3a overexpression inhibited human pulmonary arterial smooth muscle cells proliferation and upregulated BMPR2 expression by preventing the methylation of the BMPR2 promoter region. RNA-sequencing analysis suggested that SIN3a downregulated the expression of DNA and histone methyltransferases such as DNMT1 (DNA methyltransferase 1) and EZH2 (enhancer of zeste 2 polycomb repressive complex 2) while promoting the expression of the DNA demethylase TET1 (ten-eleven translocation methylcytosine dioxygenase 1). Mechanistically, SIN3a promoted BMPR2 expression by decreasing CTCF (CCCTC-binding factor) binding to the BMPR2 promoter. Last, we identified intratracheal delivery of adeno-associated virus serotype human SIN3a to be a beneficial therapeutic approach in PAH by attenuating pulmonary vascular and right ventricle remodeling, decreasing right ventricle systolic pressure and mean pulmonary arterial pressure, and restoring BMPR2 expression in rodent models of PAH.

CONCLUSIONS

All together, our study unveiled the protective and beneficial role of SIN3a in pulmonary hypertension. We also identified a novel and distinct molecular mechanism by which SIN3a regulates BMPR2 in human pulmonary arterial smooth muscle cells. Our study also identified lung-targeted SIN3a gene therapy using adeno-associated virus serotype 1 as a new promising therapeutic strategy for treating patients with PAH.

Metabolics of PH - an update

PURPOSE OF REVIEW

While there has been a longstanding interest in metabolic disease in pulmonary hypertension, publications in the last several years have translated basic science findings to human disease and even led to recently published studies of metabolic therapy in pulmonary arterial hypertension that are discussed here.

RECENT FINDINGS

Progress has been made in four key areas including mechanisms of insulin resistance in pulmonary arterial hypertension, the role of obesity in pulmonary vascular disease, novel clinical trials targeting metabolism in pulmonary hypertension, and the role of metabolism in chronic thromboembolic pulmonary hypertension.

SUMMARY

: Insulin resistance in pulmonary arterial hypertension is primarily in the lipid axis. There are systemic manifestations of insulin resistance including right ventricular lipotoxicity. Obesity is associated with elevation of right ventricular systolic pressure even in a healthy population and therapies in pulmonary arterial hypertension that target metabolism hold promise for improving exercise, right ventricular function, and visceral adiposity. Finally, there are emerging data that chronic thromboembolic pulmonary hypertension is similarly characterized by metabolic alterations, though the specific metabolites may be different from pulmonary arterial hypertension.

Significance of BMPR2 mutations in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a debilitating disease that results from progressive remodeling and inflammation of pulmonary arteries. PAH develops gradually, is difficult to diagnose, and has a high mortality rate. Although mutation in the bone morphogenetic protein receptor 2 (BMPR2) gene has been identified as the main genetic cause of PAH, the underlying pathways involving the pathophysiology of PAH are complex and still not fully understood. Endothelial dysfunction has been observed in PAH development that results in a multitude of disturbances in the cellular processes in pulmonary vessels. Changes in the pulmonary vasculature caused by the disruption of BMPR2 signaling are observed in three main vascular components; endothelial cells, smooth muscle cells, and fibroblasts. BMPR2 also has a prominent role in maintenance of the immune system. The disruption of BMPR2 signaling pathway causes an increased degree of inflammation and decreases the ability of the immune system to resolve it. Inflammatory processes and changes in pulmonary vasculature interact with one another, resulting in the progression of chronic PAH. In this review, we highlight the various components of vascular remodeling and immune response that are caused by disruption of BMPR2 signaling, including the clinical evidence and the prospects of these components as a potential target for PAH therapy. Indeed, development of drugs to target the pathogenic pathways involved in PAH may complement existing treatment regimens and improve patient prognosis.

The Role of JAK/STAT Molecular Pathway in Vascular Remodeling Associated with Pulmonary Hypertension

Pulmonary hypertension is defined as a group of diseases characterized by a progressive increase in pulmonary vascular resistance (PVR), which leads to right ventricular failure and premature death. There are multiple clinical manifestations that can be grouped into five different types. Pulmonary artery remodeling is a common feature in pulmonary hypertension (PH) characterized by endothelial dysfunction and smooth muscle pulmonary artery cell proliferation. The current treatments for PH are limited to vasodilatory agents that do not stop the progression of the disease. Therefore, there is a need for new agents that inhibit pulmonary artery remodeling targeting the main genetic, molecular, and cellular processes involved in PH. Chronic inflammation contributes to pulmonary artery remodeling and PH, among other vascular disorders, and many inflammatory mediators signal through the JAK/STAT pathway. Recent evidence indicates that the JAK/STAT pathway is overactivated in the pulmonary arteries of patients with PH of different types. In addition, different profibrotic cytokines such as IL-6, IL-13, and IL-11 and growth factors such as PDGF, VEGF, and TGFβ1 are activators of the JAK/STAT pathway and inducers of pulmonary remodeling, thus participating in the development of PH. The understanding of the participation and modulation of the JAK/STAT pathway in PH could be an attractive strategy for developing future treatments. There have been no studies to date focused on the JAK/STAT pathway and PH. In this review, we focus on the analysis of the expression and distribution of different JAK/STAT isoforms in the pulmonary arteries of patients with different types of PH. Furthermore, molecular canonical and noncanonical JAK/STAT pathway transactivation will be discussed in the context of vascular remodeling and PH. The consequences of JAK/STAT activation for endothelial cells and pulmonary artery smooth muscle cells’ proliferation, migration, senescence, and transformation into mesenchymal/myofibroblast cells will be described and discussed, together with different promising drugs targeting the JAK/STAT pathway in vitro and in vivo.

Identifying Potential Mutations Responsible for Cases of Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is a progressive and devastating disease for which there is an escalating body of genetic and related pathophysiological information on disease pathobiology. Nevertheless, the success to date in identifying susceptibility genes, genetic variants and epigenetic processes has been limited due to PAH clinical multi-faceted variations. A number of germline gene candidates have been proposed but demonstrating consistently the association with PAH has been problematic, at least partly due to the reduced penetrance and variable expressivity. Although the data for bone morphogenetic protein receptor type 2 (BMPR2) and related genes remains undoubtedly the most extensive, recent advanced gene sequencing technologies have facilitated the discovery of further gene candidates with mutations among those with and without familial forms of PAH. An in depth understanding of the multitude of biologic variations associated with PAH may provide novel opportunities for therapeutic intervention in the coming years. This knowledge will irrevocably provide the opportunity for improved patient and family counseling as well as improved PAH diagnosis, risk assessment, and personalized treatment.

Targeting transforming growth factor-β receptors in pulmonary hypertension

The transforming growth factor-β (TGF-β) superfamily includes several groups of multifunctional proteins that form two major branches, namely the TGF-β-activin-nodal branch and the bone morphogenetic protein (BMP)-growth differentiation factor (GDF) branch. The response to the activation of these two branches, acting through canonical (small mothers against decapentaplegic (Smad) 2/3 and Smad 1/5/8, respectively) and noncanonical signalling pathways, are diverse and vary for different environmental conditions and cell types. An extensive body of data gathered in recent years has demonstrated a central role for the cross-talk between these two branches in a number of cellular processes, which include the regulation of cell proliferation and differentiation, as well as the transduction of signalling cascades for the development and maintenance of different tissues and organs. Importantly, alterations in these pathways, which include heterozygous germline mutations and/or alterations in the expression of several constitutive members, have been identified in patients with familial/heritable pulmonary arterial hypertension (PAH) or idiopathic PAH (IPAH). Consequently, loss or dysfunction in the delicate, finely-tuned balance between the TGF-β-activin-nodal branch and the BMP-GDF branch are currently viewed as the major molecular defect playing a critical role in PAH predisposition and disease progression. Here we review the role of the TGF-β-activin-nodal branch in PAH and illustrate how this knowledge has not only provided insight into understanding its pathogenesis, but has also paved the way for possible novel therapeutic approaches.

Epigenetic Regulation of Pulmonary Arterial Hypertension-Induced Vascular and Right Ventricular Remodeling: New Opportunities?

Pulmonary artery hypertension (PAH) is a rare chronic disease with high impact on patients’ quality of life and currently no available cure. PAH is characterized by constant remodeling of the pulmonary artery by increased proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), fibroblasts (FBs) and endothelial cells (ECs). This remodeling eventually leads to increased pressure in the right ventricle (RV) and subsequent right ventricle hypertrophy (RVH) which, when left untreated, progresses into right ventricle failure (RVF). PAH can not only originate from heritable mutations, but also develop as a consequence of congenital heart disease, exposure to drugs or toxins, HIV, connective tissue disease or be idiopathic. While much attention was drawn into investigating and developing therapies related to the most well understood signaling pathways in PAH, in the last decade, a shift towards understanding the epigenetic mechanisms driving the disease occurred. In this review, we reflect on the different epigenetic regulatory factors that are associated with the pathology of RV remodeling, and on their relevance towards a better understanding of the disease and subsequently, the development of new and more efficient therapeutic strategies.

At the X-Roads of Sex and Genetics in Pulmonary Arterial Hypertension

Group 1 pulmonary hypertension (pulmonary arterial hypertension; PAH) is a rare disease characterized by remodeling of the small pulmonary arteries leading to progressive elevation of pulmonary vascular resistance, ultimately leading to right ventricular failure and death. Deleterious mutations in the serine-threonine receptor bone morphogenetic protein receptor 2 (BMPR2; a central mediator of bone morphogenetic protein (BMP) signaling) and female sex are known risk factors for the development of PAH in humans. In this narrative review, we explore the complex interplay between the BMP and estrogen signaling pathways, and the potentially synergistic mechanisms by which these signaling cascades increase the risk of developing PAH. A comprehensive understanding of these tangled pathways may reveal therapeutic targets to prevent or slow the progression of PAH.

The Value of Hemodynamic Measurements or Cardiac MRI in the Follow-up of Patients With Idiopathic Pulmonary Arterial Hypertension

Background

Treatment of patients with pulmonary arterial hypertension (PAH) is conventionally based on functional plus invasive measurements obtained during right heart catheterization (RHC). Whether risk assessment during repeated measurements could also be performed on the basis of imaging parameters is unclear, as a direct comparison of strategies is lacking.

Research Question

How does the predictive value of noninvasive parameters compare with that of invasive hemodynamic measurements 1 year after the diagnosis of idiopathic PAH?

Study Design and Methods

One hundred and eighteen patients with idiopathic PAH who underwent RHC and cardiac MRI (CMR) were included in this study (median time between baseline evaluation and first parameter measures, 1.0 [0.8-1.2] years). Forty-four patients died or underwent lung transplantation. Forward Cox regression analyses were done to determine the best predictive functional, hemodynamic, and/or imaging model. Patients were classified as high risk if the event occurred < 5 years after diagnosis (n = 24), whereas patients without event were classified as low risk.

Results

A prognostic model based on age, sex, and absolute values at follow-up of functional parameters (6-min walk distance) performed well (Akaike information criterion [AIC], 279; concordance, 0.67). Predictive models with only hemodynamic (right atrial pressure, mixed venous oxygen saturation; AIC, 322; concordance, 0.66) or imaging parameters (right ventricular ejection fraction; AIC, 331; concordance, 0.63) at 1 year of follow-up performed similarly. The predictive value improved when functional data were combined with either hemodynamic data (AIC, 268; concordance, 0.69) or imaging data (AIC, 273; concordance, 0.70). A model composed of functional, hemodynamic, and imaging data performed only marginally better (AIC, 266; concordance, 0.69). Finally, changes between baseline and 1-year follow-up were observed for multiple hemodynamic and CMR parameters; only a change in CMR parameters was of prognostic predictive value.

Interpretation

At 1 year of follow-up, risk assessment based on CMR is at least equal to risk assessment based on RHC. In this study, only changes in CMR, but not hemodynamic parameters, were of prognostic predictive value during the first year of follow-up.

Endothelial BMPR2 Loss Drives a Proliferative Response to BMP (Bone Morphogenetic Protein) 9 via Prolonged Canonical Signaling

Supplemental Digital Content is available in the text.

Pulmonary arterial hypertension is a disease of proliferative vascular occlusion that is strongly linked to mutations in BMPR2—the gene encoding the BMPR-II (BMP [bone morphogenetic protein] type II receptor). The endothelial-selective BMPR-II ligand, BMP9, reverses disease in animal models of pulmonary arterial hypertension and suppresses the proliferation of healthy endothelial cells. However, the impact of BMPR2 loss on the antiproliferative actions of BMP9 has yet to be assessed.

Prevalence and clinical features of bone morphogenetic protein receptor type 2 mutation in Korean idiopathic pulmonary arterial hypertension patients: The PILGRIM explorative cohort

Background

Pulmonary arterial hypertension (PAH) is a progressive chronic disease with poor outcomes. One reason for poor prognosis is the lack of understanding regarding individual variability in response to treatment. Idiopathic PAH (IPAH) patients with bone morphogenetic protein receptor type 2 (BMPR2) mutations have distinct phenotypes that are crucial for individualized therapy but evidence regarding their prevalence and clinical features in the Korean population is lacking. Therefore, the present study aimed to screen Korean IPAH patients for BMPR2 mutations and analyze their clinical phenotypes.

Methods

We enrolled 73 unrelated IPAH patients for BMPR2 mutation screening between March 2010 to November 2015 from 11 hospitals in Korea. Thirty-three lineal family members from 6 families of BMPR2 mutation carriers were also screened.

Results

Among 73 patients, 16 (22%) had BMPR2 mutations. Mutation carriers were younger (27 vs. 47 years; p = 0.02) and had a higher mean pulmonary arterial pressure (mPAP) than non-carriers (64 vs. 51 mmHg; p<0.05). Of the 16 individuals with mutations, 5 deletion, 2 splice-site, 6 nonsense, and 3 missense mutations were found, among which, 9 were newly identified mutation types. Patients less than 30 years old had more BMPR2 mutations (44 vs. 14%; p = 0.04) and a higher mPAP (64 vs. 50 mmHg; p = 0.04) compared with those equaled to or over 30 years old. There were no differences in hemodynamic profiles or the proportion of BMPR2 mutation carriers between groups according to sex.

Conclusion

The prevalence of BMPR2 mutations in Korean IPAH patients was 22%. Mutation carriers were younger and had a poorer hemodynamic profile compared with the non-carriers.

Clinical trial registration

Clinicaltrials.gov NCT01054105

The features of rare pathogenic BMPR2 variants in pulmonary arterial hypertension: Comparison between patients and reference population

BACKGROUND

Mutations in the gene encoding bone morphogenetic protein receptor type 2 (BMPR2) are the most common genetic risk factors underlying pulmonary arterial hypertension (PAH). However, the features of PAH-related BMPR2 rare variants remain unclear. We propose that the discrepancy of BMPR2 rare variants landscape between patients with PAH and reference population would be important to address the genetic background of PAH-related variants.

METHODS

We genotyped BMPR2 rare variants in 670 Chinese patients with pulmonary arterial hypertension. The BMPR2 rare variants were screened in 10,508 reference people from two exome databases.

RESULTS

The prevalence of rare BMPR2 variants in patients with PAH was significantly higher compared to the reference population (21.5%, 144/670 vs 0.87%, 91/10508, p = 1.3 × 10^-118). In patients with PAH, 49% of identified BMPR2 rare variants were loss-of-function or splicing. These BMPR2 rare variants were only observed in 1% of the reference population (p = 9.0 × 10^-12). Arg491, which is absent in the reference population, represented as hot-spot site (14.6%, 21/144) in PAH patients. BMPR2 missense mutations in PAH patients were more likely distributed in extracellular ligand-binding domain (ECD, 29.7% vs 11.1%, p < 0.001). Compared with Non-PAH-related variations, PAH-related missense variants tend to alter the amino acid electric status (51.4% vs 23.3%, p < 0.001).

CONCLUSIONS

BMPR2 variants located in extracellular ligand-binding domain or altered the amino acid electric status are more pathogenic.

Genetic Admixture and Survival in Diverse Populations with Pulmonary Arterial Hypertension

Rationale: Limited information is available on racial/ethnic differences in pulmonary arterial hypertension (PAH).Objectives: Determine effects of race/ethnicity and ancestry on mortality and disease outcomes in diverse patients with PAH.Methods: Patients with Group 1 PAH were included from two national registries with genome-wide data and two local cohorts, and further incorporated in a global meta-analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for transplant-free, all-cause mortality in Hispanic patients with non-Hispanic white (NHW) patients as the reference group. Odds ratios (ORs) for inpatient-specific mortality in patients with PAH were also calculated for race/ethnic groups from an additional National Inpatient Sample dataset not included in the meta-analysis.Measurements and Main Results: After covariate adjustment, self-reported Hispanic patients (n = 290) exhibited significantly reduced mortality versus NHW patients (n = 1,970) after global meta-analysis (HR, 0.60 [95% CI, 0.41-0.87]; P = 0.008). Although not significant, increasing Native American genetic ancestry appeared to account for part of the observed mortality benefit (HR, 0.48 [95% CI, 0.23-1.01]; P = 0.053) in the two national registries. Finally, in the National Inpatient Sample, an inpatient mortality benefit was also observed for Hispanic patients (n = 1,524) versus NHW patients (n = 8,829; OR, 0.65 [95% CI, 0.50-0.84]; P = 0.001). An inpatient mortality benefit was observed for Native American patients (n = 185; OR, 0.38 [95% CI, 0.15-0.93]; P = 0.034).Conclusions: This study demonstrates a reproducible survival benefit for Hispanic patients with Group 1 PAH in multiple clinical settings. Our results implicate contributions of genetic ancestry to differential survival in PAH.

Novel Molecular Mechanisms of Pulmonary Hypertension: A Search for Biomarkers and Novel Drug Targets-From Bench to Bed Site

Pulmonary hypertension (PH) is defined as increased mean pulmonary artery pressure (mPAP) above 25 mmHg, measured at rest by right heart catheterization. The exact global prevalence of PH is difficult to estimate, mainly due to the complex aetiology, and its spread may be underestimated. To date, numerous studies on the aetiology and pathophysiology of PH at molecular level were conducted. Simultaneously, some clinical studies have shown potential usefulness of well-known and widely recognized cardiovascular biomarkers, but their potential clinical usefulness in diagnosis and management of PH is poor due to their low specificity accompanied with numerous other cardiovascular comorbidities of PH subjects. On the other hand, a large body of basic research-based studies provides us with novel molecular pathomechanisms, biomarkers, and drug targets, according to the evidence-based medicine principles. Unfortunately, the simple implementation of these results to clinical practice is impossible due to a large heterogeneity of the PH pathophysiology, where the clinical symptoms constitute only a common denominator and a final result of numerous crosstalking metabolic pathways. Therefore, future studies, based mostly on translational medicine, are needed in order to both organize better the pathophysiological classification of various forms of PH and define precisely the optimal diagnostic markers and therapeutic targets in particular forms of PH. This review paper summarizes the current state of the art regarding the molecular background of PH with respect to its current classification. Novel therapeutic strategies and potential biomarkers are discussed with respect to their limitations in use in common clinical practice.

Transcriptomic analysis of pulmonary artery smooth muscle cells identifies new potential therapeutic targets for idiopathic pulmonary arterial hypertension

BACKGROUND AND PURPOSE

Pulmonary arterial hypertension (PAH, type 1 pulmonary hypertension) has a 3-year survival of ~50% and is in need of new, effective therapies. In PAH, remodelling of the pulmonary artery (PA) increases pulmonary vascular resistance and can result in right heart dysfunction and failure. Genetic mutations can cause PAH but it can also be idiopathic (IPAH). Enhanced contractility and proliferation of PA smooth muscle cells (PASMCs) are key contributors to the pathophysiology of PAH, but the underlying mechanisms are not well understood.

EXPERIMENTAL APPROACH

We utilized RNA-sequencing (RNA-seq) of IPAH and control patient-derived PASMCs as an unbiased approach to define differentially expressed (DE) genes that may identify new biology and potential therapeutic targets.

KEY RESULTS

Analysis of DE genes for shared gene pathways revealed increases in genes involved in cell proliferation and mitosis and decreases in a variety of gene sets, including response to cytokine signalling. ADGRG6/GPR126, an adhesion G protein-coupled receptor (GPCR), was increased in IPAH-PASMCs compared to control-PASMCs. Increased expression of this GPCR in control-PASMCs decreased their proliferation; siRNA knockdown of ADGRG6/GPR126 in IPAH-PASMCs tended to increase proliferation.

CONCLUSION AND IMPLICATIONS

These data provide insights regarding the expression of current and experimental PAH drug targets, GPCRs and GPCR-related genes as potentially new therapeutic targets in PAH-PASMCs. Overall, the findings identify genes and pathways that may contribute to IPAH-PASMC function and suggest that ADGRG6/GPR126 is a novel therapeutic target for IPAH.

Phenotype and outcome of pulmonary arterial hypertension patients carrying a TBX4 mutation

Introduction

TBX4 mutation causes small patella syndrome (SPS) and/or pulmonary arterial hypertension (PAH). The characteristics and outcomes of PAH associated with TBX4 mutations are largely unknown.

Methods

We report the clinical, functional, radiologic, histologic and haemodynamic characteristics and outcomes of heritable PAH patients carrying a TBX4 mutation from the French pulmonary hypertension (PH) network.

Results

20 patients were identified in 17 families. They were characterised by a median age at diagnosis of 29 years (0–76 years) and a female to male ratio of three. Most of the patients (70%) were in New York Heart Association (NYHA) functional class III or IV with a severe haemodynamic impairment (median pulmonary vascular resistance (PVR) of 13.6 (6.2–41.8) Wood units). Skeletal signs of SPS were present in 80% of cases. Half of the patients had mild restrictive or obstructive limitation and diffusing capacity of the lung for carbon monoxide (DLCO) was decreased in all patients. High-resolution computed tomography (HRCT) showed bronchial abnormalities, peri-bronchial cysts, mosaic distribution and mediastinal lymphadenopathies. PAH therapy was associated with significant clinical improvement. At follow-up (median 76 months), two patients had died and two had undergone lung transplantation. One-year, three-year and five-year event-free survival rates were 100%, 94% and 83%, respectively. Histologic examination of explanted lungs revealed alveolar growth abnormalities, major pulmonary vascular remodelling similar to that observed in idiopathic pulmonary arterial hypertension (IPAH) and accumulation of cholesterol crystals within the lung parenchyma.

Conclusion

PAH due to TBX4 mutations may occur with or without skeletal abnormalities across a broad age range from birth to late adulthood. PAH is usually severe and associated with bronchial and parenchymal abnormalities.

Gender differences in pulmonary arterial hypertension patients with BMPR2 mutation: a meta-analysis

OBJECTIVE

To investigate the differences in the proportions of BMPR2 mutations in familial hereditary pulmonary arterial hypertension (HPAH) and idiopathic pulmonary arterial hypertension (IPAH) between males and females and the relationship between BMPR2 mutation and PAH severity.

METHODS

A computer was used to search the electronic Cochrane Library, PubMed/MEDLINE, and EMBASE databases for clinical trials containing information on the relationship between PAH prognosis and BMPR2 mutations through March 2019. After obtaining the data, a meta-analysis was performed using Review Manager Version 5.3 and Stata.

RESULTS

A meta-analysis was performed on 17 clinical trials (2198 total patients: 644 male, 1554 female). The results showed that among patients with HPAH and IPAH, the BMPR2 mutation rate is higher in male than in female patients [male group (224/644, 34.78%), female group (457/1554, 29.41%), OR = 1.30, 95% CI: 1.06~1.60, P = 0.01, I² = 10%]. Furthermore, haemodynamic and functional parameters were more severe in IPAH and HPAH patients with BMPR2 mutations than in those without, and those with BMPR2 mutation were diagnosed at a younger age. The risk of death or transplantation was higher in PAH patients with BMPR2 mutations than in those without (OR = 2.51, 95% CI: 1.29~3.57, P = 0.003, I² = 24%). Furthermore, the difference was significant only in male patients (OR = 5.58, 95% CI: 2.16~14.39, P = 0.0004, I² = 0%) and not in female patients (OR = 1.41, 95% CI: 0.75~2.67, P = 0.29, I² = 0%).

CONCLUSION

Among patients with HPAH and IPAH, men are more likely to have BMPR2 mutations, which may predict more severe PAH indications and prognosis.

BMPR2 dysfunction impairs insulin signaling and glucose homeostasis in cardiomyocytes

Insulin resistance and right ventricular (RV) dysfunction are associated with lipotoxicity in heritable forms of pulmonary arterial hypertension (PAH), commonly due to mutations in bone morphogenetic protein receptor type 2 (BMPR2). How BMPR2 dysfunction in cardiomyocytes alters glucose metabolism and the response of these cells to insulin are unknown. We hypothesized that BMPR2 mutation in cardiomyocytes alters glucose-supported mitochondrial respiration and impairs cellular responses to insulin, including glucose and lipid uptake. We performed metabolic assays, immunofluorescence and Western analysis, RNA profiling, and radioactive isotope uptake studies in H9c2 cardiomyocyte cell lines with and without patient-derived BMPR2 mutations (mutant cells), with and without insulin. Unlike control cells, BMPR2 mutant cardiomyocytes have reduced metabolic plasticity as indicated by reduced mitochondrial respiration with increased mitochondrial superoxide production. These mutant cells show enhanced baseline phosphorylation of insulin-signaling protein as indicated by increased Akt, AMPK, and acetyl-CoA carboxylase phosphorylation that may negatively influence fatty acid oxidation and enhance lipid uptake, and are insulin insensitive. Furthermore, mutant cells demonstrate an increase in milk fat globule-EGF factor-8 protein (MFGE8), which influences the insulin-signaling pathway by phosphorylating AktSer473 via phosphatidylinositol 3-kinase and mammalian target of rapamycin. In conclusion, BMPR2 mutant cardiomyocytes have reduced metabolic plasticity and fail to respond to glucose. These cells have enhanced baseline insulin-signaling pattern favoring insulin resistance with failure to augment this pattern in response to insulin. BMPR2 mutation possibly blunts glucose uptake and enhances lipid uptake in these cardiomyocytes. The MFGE8-driven signaling pathway may suggest a new mechanism underlying RV lipotoxicity in PAH.

Sex hormone exposure and reproductive factors in pulmonary arterial hypertension: a case-control study

Pulmonary arterial hypertension (PAH) is a sexually dimorphic disease that for unknown reasons affects women more than men. The role of estrogens, both endogenous and exogenous, and reproductive factors in this female susceptibility is still poorly understood. It has been strongly suggested that sex hormones may influence the development and progression of the disease. We sought to determine whether sex hormone exposures and reproductive factors associate with PAH patients compared to control subjects, using a questionnaire and interview to obtain information regarding these potential risk factors. We conducted a single-center unmatched case-control study. Six hundred and thirty-four women and men with PAH, as well as 27 subjects with BMPR2 mutations but no PAH and 132 healthy population controls were enrolled from the Vanderbilt Pulmonary Hypertension Research Cohort and researchmatch.org. Questionnaires and nurse-led interviews were conducted to obtain information regarding sex hormone exposures and reproductive factors. Additional history was obtained on enrolled patients including disease severity variables and comorbidities. Responses to the questionnaires were analyzed to describe these exposures in this population as well as assess the association between disease severity variables and sex hormone exposures. Reproductive and endogenous factors that determine lifelong estrogen exposure were similar between PAH cases and controls. Patients with associated PAH were significantly more likely to be postmenopausal compared to controls. There were similar rates of "ever-use" and duration of use of oral contraceptive pills and hormone replacement therapy in patients when compared to controls. Disease severity variables were not significantly affected by any exposure after adjusting for PAH sub-group. In contrast to our hypothesis, that a greater exposure to exogenous sources of female sex hormones associates with PAH case status, we found similar rates of endogenous and exogenous sex hormone exposure between PAH patients and unmatched controls.

Current status of pulmonary arterial hypertension in Korea

Pulmonary arterial hypertension (PAH) is characterized by remodeling of the distal pulmonary arteries resulting in high pulmonary vascular resistance and, eventually, right ventricular heart failure. Although current advances in PAH therapy have improved outcomes, poor survival remains a reality worldwide, including Korea. One of the most important issues in PAH is the late diagnosis, since screening or diagnostic efforts are often overlooked due to the rarity of disease. Data from Korean registries and observational cohorts show that delayed detection leads to increased morbidity. Additionally, low percentages of Korean patients are committed to intensive PAH-targeted therapy. Current Korean health insurance policies' lack of coverage for new PAH-targeted drugs and upfront combination therapy may also hamper the improvement of treatment outcomes. Understanding individual variability in response to therapeutics through deep phenotyping is a novel strategy that should be considered when treating PAH. Overall, early detection of PAH by proactive screening together with early, intensive, individualized PAH therapy using deep phenotyping is crucial for improving prognoses for PAH patients in Korea.

United States Pulmonary Hypertension Scientific Registry (USPHSR): rationale, design, and clinical implications

Diagnostic World Health Organization (WHO) Group 1 pulmonary arterial hypertension (PAH) and Diagnostic Group 1' pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH) are progressive and fatal disorders. Past registries provided important insights into these disorders, but did not include hormonal exposures or genomic data. The United States Pulmonary Hypertension Scientific Registry (USPHSR) will provide demographic, physiologic, anorexigen and hormone exposure, genomic, and survival data in the current therapeutic era for 499 patients diagnosed with PAH, PVOD, or PCH. The USPHSR also will explore the relationship between pharmacologic, non-pharmacologic, and dietary hormonal exposures and the increased risk for women to develop idiopathic or heritable PAH.

The Use of Risk Assessment Tools and Prognostic Scores in Managing Patients with Pulmonary Arterial Hypertension

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) is a chronic, progressive, and incurable disease with significant morbidity and mortality. Despite increasingly available treatment options, PAH patients continue to experience disease progression and increased rates of hospitalizations due to right heart failure. Physician's ability to comprehensively assess PAH patients, determine prognosis, and monitor disease progression and response to treatment remains critical in optimizing outcomes.

RECENT FINDINGS

Risk assessment in PAH should include a range of clinical, hemodynamic, and exercise parameters, performed in a serial fashion over the course of treatment. Approaches to risk assessment in PAH patients include the use of risk variables, scores, and equations that stratify the impact of both modifiable (e.g., 6-min walk distance, functional class, brain natriuretic peptide), and non-modifiable (e.g., age, gender, PAH etiology) risk factors. Such tools allow physicians to better determine prognosis, allocate treatment resources, and enhance the consistency of treatment approaches across providers. Comprehensive and accurate risk prediction is essential to make individualized treatment decisions and optimizing outcomes in PAH.

Genetics and genomics of pulmonary arterial hypertension

Since 2000 there have been major advances in our understanding of the genetic and genomics of pulmonary arterial hypertension (PAH), although there remains much to discover. Based on existing knowledge, around 25-30% of patients diagnosed with idiopathic PAH have an underlying Mendelian genetic cause for their condition and should be classified as heritable PAH (HPAH). Here, we summarise the known genetic and genomic drivers of PAH, the insights these provide into pathobiology, and the opportunities afforded for development of novel therapeutic approaches. In addition, factors determining the incomplete penetrance observed in HPAH are discussed. The currently available approaches to genetic testing and counselling, and the impact of a genetic diagnosis on clinical management of the patient with PAH, are presented. Advances in DNA sequencing technology are rapidly expanding our ability to undertake genomic studies at scale in large cohorts. In the future, such studies will provide a more complete picture of the genetic contribution to PAH and, potentially, a molecular classification of this disease.

Exome data clouds the pathogenicity of genetic variants in Pulmonary Arterial Hypertension

BACKGROUND

We aimed to provide a set of previously reported PAH-associated missense and nonsense variants, and evaluate the pathogenicity of those variants.

METHODS

The Human Gene Mutation Database, PubMed, and Google Scholar were searched for previously reported PAH-associated genes and variants. Thereafter, both exome sequencing project and exome aggregation consortium as background population searched for previously reported PAH-associated missense and nonsense variants. The pathogenicity of previously reported PAH-associated missense variants evaluated by using four in silico prediction tools.

RESULTS

In total, 14 PAH-associated genes and 180 missense and nonsense variants were gathered. The BMPR2, the most frequent reported gene, encompasses 135 of 180 missense and nonsense variants. The exome sequencing project comprised 9, and the exome aggregation consortium counted 25 of 180 PAH-associated missense and nonsense variants. The TOPBP1 and ENG genes are unlikely to be the monogenic cause of PAH pathogenesis based on allele frequency in background population and prediction analysis.

CONCLUSION

This is the first evaluation of previously reported PAH-associated missense and nonsense variants. The BMPR2 identified as the major gene out of 14 PAH-associated genes. Based on findings, the ENG and TOPBP1 gene are not likely to be the monogenic cause of PAH.

Consequences of BMPR2 Deficiency in the Pulmonary Vasculature and Beyond: Contributions to Pulmonary Arterial Hypertension

Since its association with familial pulmonary arterial hypertension (PAH) in 2000, Bone Morphogenetic Protein Receptor II (BMPR2) and its related signaling pathway have become recognized as a key regulator of pulmonary vascular homeostasis. Herein, we define BMPR2 deficiency as either an inactivation of the receptor, decreased receptor expression, or an impairment of the receptor’s downstream signaling pathway. Although traditionally the phenotypic consequences of BMPR2 deficiency in PAH have been thought to be limited to the pulmonary vasculature, there is evidence that abnormalities in BMPR2 signaling may have consequences in many other organ systems and cellular compartments. Revisiting how BMPR2 functions throughout health and disease in cells and organs beyond the lung vasculature may provide insight into the contribution of these organ systems to PAH pathogenesis as well as the potential systemic manifestation of PAH. Here we review our knowledge of the consequences of BMPR2 deficiency across multiple organ systems.

CONTEMPORARY STRATEGY OF PULMONARY HYPERTENSION MANAGEMENT IN PEDIATRICS

Pulmonary hypertension (PH) in pediatrics is a polygenic multifactorial condition with extremely adverse prognosis. Selection of optimal management is a severe task. In absence of treatment the mean life duration in children is not higher one year. Last two decades, revolution in approaches to treatment improved the survival of this patients group. Recently, pediatricians and pediatric cardiologists have three drugs groups that act on the main pathogenetic chains of PH: endothelin pathway, nitric oxide pathway and prostacyclin pathway. At the moment, approaches to pediatric PH are based on the data obtained in the trials on adult patients. However, not long ago there were first randomized trials on children performed. The group of authors of current article presents a modern view on the problem of PH in children, and expert recommendations on children management. Class of recommendations and evidence level were set by the data obtained in pediatric population or on adult population with at least 10% of children included. To the strategy, developed by the Russian clinicians, laid the analysis of experience of the pathology treatment in Russian Federation, as the current practics and clinical guidelines on pediatric PH in Europe, and the recent trials published.