Features Of Pulmonary Arterial Hypertension Research Articles

1,8-Cineole reduces pulmonary vascular remodelling in pulmonary arterial hypertension by restoring intercellular communication and inhibiting angiogenesis.

Pulmonary Arterial Hypertension (PAH) is characterized by pulmonary vascular remodelling, often associated with disruption of BMPR2/Smad1/5 and BMPR2/PPAR-γ signalling pathways that ultimately lead to right ventricle failure. Disruption of intercellular junctions and communication and a pro-angiogenic environment are also characteristic features of PAH. Although, current therapies improve pulmonary vascular tone, they fail to tackle other key pathological features that could prevent disease progression. In this scenario, aromatic plants emerge as promising sources of bioactive compounds, with 1,8-cineole standing out due to its hypotensive properties and cardioprotective effect in PAH. The present study aims to explore for the first time the effect of 1,8-cineole in pulmonary vascular remodelling associated with PAH. Resorting to the monocrotaline (MCT)-induced PAH animal model, the effect of 1,8-cineole on vascular remodelling including interstitial collagen accumulation, smooth muscle cell proliferation and protein levels of BMPR2 pathway-related proteins, was assessed by microscopy and western blot (WB) analysis. The integrity of gap junctions, pulmonary surfactant, mitochondrial structure and endothelial cell barrier were evaluated by transmission electron microscopy, confocal microscopy and WB analysis. Furthermore, the effect of 1,8-cineole on angiogenesis was determined on pulmonary artery endothelial cells (PAEC) submitted to hypoxia using the scratch wound and Matrigel angiogenesis assays, and the number of sprouts on isolated healthy and diseased pulmonary artery rings, treated with the compound, enabled the validation of these effects. 1,8-Cineole mitigated PAH-associated derailment of both BMPR2/Smad1/5 and BMPR2/PPAR-γ pathways and concomitantly reduced interstitial fibrosis and the arterial medial layer thickness in pulmonary arteries. The compound restored gap junction, lung surfactant and mitochondrial integrity and preserved endothelial barrier integrity. Furthermore, 1,8-cineole exerted an anti-angiogenic effect, by impairing the formation of vessel-like structures in PAEC and sprouting formation in isolated pulmonary arteries. The present study brings new insights about the mechanisms whereby 1,8-cineole impacts pulmonary vascular remodelling and demonstrates the potential of 1,8-cineole as a therapeutic strategy to hamper PAH progression.

Effects of BET Inhibition on lung micro-environmental changes in obesity-related pulmonary Arterial Hypertension (PAH)

Abstract Background Obesity is emerging as a pivotal risk factor for pulmonary arterial hypertension (PAH) but the underlying molecular mechanisms are poorly explored. The lung microenvironment, namely the cell-cell communication among fibroblasts, immune and endothelial cells, may significantly impact on vascular structure and function thus promoting microvascular disease in this setting. Obesity-induced chromatin modifications lead to maladaptive transcriptional programs altering cell function in different organs. Apabetalone (APA), a selective inhibitor of bromodomain and extra-terminal containing protein family (BET) proteins, prevents bromodomain-containing protein 4 (BRD4) interactions with chromatin thus modulating gene expression. Purpose To determine whether a new epi-drug, namely APA, affects the lung microenvironment in obesity-related PAH. Methods Mice were fed a normal diet (ND, control) or high-fat-diet (HFD) and L-NAME for 15 weeks to induce obesity-related PAH (obPAH). Echocardiography was performed. Pathways regulating obPAH were identified by single-cell nuclei RNA sequencing in lung specimens. Primary endothelial cells (ECs) and Fibroblasts (mFs) were freshly isolated from obPAH lungs and treated with APA for 48 hours. Cells and lung samples were used for molecular biology and histology. Cellular migration was investigated by in vitro gap closure. Results Obese mice displayed PAH as shown by increased pulmonary artery (PA) pressure, PA resistance, right ventricular wall thickness and reduced PA acceleration time. Of note, chronic APA treatment prevented PAH-related features in obese mice. To determine the cell types affected by APA, we performed scRNAseq. We found that fibroblast and endothelial cells had the highest enrichment of genes whose expression significantly correlated with echo-determined PAH features. ECs and mFs from obese mice displayed an altered phenotype whereas treatment with APA rescued obesity-driven ECs and mFs dysfunction. In obPAH ECs, we found increased expression of NF-kB p65-related inflammatory genes (IL-1β, IL-6, TNF-alpha) as well as enhanced p53 signaling. Moreover, obPAH-ECs expressed high levels of hypoxia-inducible factor (HIF1-α) and NADPH-oxidase-NOX4 with subsequent increase in ROS generation. Furthermore, APA treatment protected against cellular inflammation, senescence and oxidative stress. To evaluate the effect of APA and the paracrine response of fibroblasts, we performed a scratch assay on control mFs exposed to TGF-β or conditioned media collected from obPAH-ECs with and without APA. In both experimental settings, APA affected gap closure, suggesting that the treatment influences fibroblast migration through both a direct effect and paracrine mechanisms. Conclusions APA is able to reset the lung micro-envirnment in obesity thus reducing inflammation and senescence. BET inhibitors could represent potential therapeutic approaches in this setting.

Current Overview of the Biology and Pharmacology in Sugen/Hypoxia-Induced Pulmonary Hypertension in Rats.

The Sugen 5416/hypoxia (Su/Hx) rat model of pulmonary arterial hypertension (PAH) demonstrates most of the distinguishing features of PAH in humans, including increased wall thickness and obstruction of the small pulmonary arteries along with plexiform lesion formation. Recently, significant advancement has been made describing the epidemiology, genomics, biochemistry, physiology, and pharmacology in Su/Hx challenge in rats. For example, there are differences in the overall reactivity to Su/Hx challenge in different rat strains and only female rats respond to estrogen treatments. These conditions are also encountered in human subjects with PAH. Also, there is a good translation in both the biochemical and metabolic pathways in the pulmonary vasculature and right heart between Su/Hx rats and humans, particularly during the transition from the adaptive to the nonadaptive phase of right heart failure. Noninvasive techniques such as echocardiography and magnetic resonance imaging have recently been used to evaluate the progression of the pulmonary vascular and cardiac hemodynamics, which are important parameters to monitor the efficacy of drug treatment over time. From a pharmacological perspective, most of the compounds approved clinically for the treatment of PAH are efficacious in Su/Hx rats. Several compounds that show efficacy in Su/Hx rats have advanced into phase II/phase III studies in humans with positive results. Results from these drug trials, if successful, will provide additional treatment options for patients with PAH and will also further validate the excellent translation that currently exists between Su/Hx rats and the human PAH condition.

Computed Tomography Spectrum of Complications in Usual Interstitial Pneumonia Pattern in a Tertiary Care Hospital: A Descriptive Cross- sectional Study.

Idiopathic pulmonary fibrosis is the most prevalent form of interstitial lung disease, which presents as usual interstitial pneumonia on histopathology and imaging. It leads to significant lung scarring, damage, and fibrosis and is associated with a high degree of mortality, repeated hospital admissions, and oxygen dependence. Many complications are associated with idiopathic pulmonary fibrosis, which further increases the morbidity of patients. High-resolution computed tomography chest is the imaging modality of choice for usual interstitial pneumonia tracking its progression, evaluating treatment response, and detecting potential complications. This descriptive cross-sectional study was approved by the Institutional Ethics Committee (Reference number: IEC-INT/2023/Study-1256). Departmental computed tomography report database from November, 2017 to June, 2018 was reviewed and scans with imaging features consistent with the 'usual interstitial pneumonia' pattern were identified. Total sampling method was used and two independent radiologists, blinded to the patient's clinical information, reviewed the high-resolution computed tomography chest scans to assess for imaging features of usual interstitial pneumonia and associated complications. Data was collected and analyzed using Microsoft Excel. There were 65 patients reported as unusual interstitial pneumonia pattern. Emphysema and pneumothorax were identified in 4 (6.15%) and 1 (1.53%) scans, respectively. Two (3.08%) scans showed features of pulmonary arterial hypertension. Ten (15.38%) scans exhibited findings consistent with co-existent or superimposed pulmonary infection. Additionally, features of lung malignancy were identified in high-resolution computed tomography scans of 5 (7.69%) patients. Patients with UIP often experience severe lung scarring, and frequent complications, and require regular chest CT scans to monitor disease progression and identify potential complications.

Evaluation of Nicorandil in Treatment of induced pulmonary arterial hypertension in male Rats

Pulmonary arterial hypertension (PAH) is a chronic, rare, and non-treatable disease, resulting in elevated mean arterial pressure (≥25mmHg) during rest and (≥30mmHg) during exercise. Pulmonary arteries remodeling including endothelial apoptosis, smooth muscle hyperplasia, and endothelial dysfunction are distinct features of PAH. This study aims to evaluate effect of nicorandil as an alternative treatment for PAH in comparison to tadalafil by evaluating its anti-inflammatory effect and histopathological changes. A total of 60 male wistar rats were divided to 6 groups, a control healthy group, and another 5 groups injected with monocrotaline to induce PAH. The induction group was left untreated while the other 4 groups were treated with either nicorandil or tadalafil, with or without treatment blockers (N-Nitroarginine methyl ester and glimepiride), after 21 days they were sacrificed for histopathology and measurement of inflammatory markers. Nicorandil reduced the levels of osteopontin, and cardiac marker brain natriuretic peptide (BNP) significantly (P≤0.05) , also it showed an improved histopathological picture of PAH by reducing smooth muscle proliferation, necrosis, and inflammation in pulmonary arteries. In conclusion, nicorandil in this study showed promising results in reducing inflammation and improving endothelial function.

A PrOsPective Cohort Study on Interstitial Lung Disease-Associated Pulmonary Hypertension with a ParticulaR Focus on the Subset with Pulmonary Arterial Hypertension Features (POPLAR Study).

The pathogenesis and clinical profiles of patients with pulmonary hypertension (PH) associated with interstitial lung disease (ILD-PH) are poorly understood. Whether and to what extent pulmonary arterial hypertension (PAH)-specific therapy improves hemodynamic and outcome in ILD-PH are also unknown. This study aims to clarify the characteristics, clinical course and response to PAH-specific therapy of ILD and/or PH by enrolling three unique subsets: PAH, ILD-PH, and ILD. The proposed study is a retrospective and prospective, multi-centre, observational cohort study of patients treated at any of three university hospitals in the Hokkaido region of Japan who have any one of the following: PAH; ILD-PH with or without PAH features; or ILD without PH. We aim to enrol 250 patients in total. For the retrospective observation period, data obtained after 1 January 2010, will be analysed, and the prospective observation period will be 1year. We will compare the clinical data of patients with ILD-PH with those of patients with PAH and those of patients with ILD without PH in the real-world clinical setting. In addition, within the cohort of patients with ILD-PH, we will explore the subset with "ILD-PH with PAH features" and compare the response to PAH-specific therapy with that of PAH. The primary outcome will be the change in pulmonary vascular resistance from first treatment to follow-up in patients with PAH and ILD-PH with PAH features (excluding ILD-PH without PAH feature and ILD-no-PH for the primary outcome). The exploratory outcomes will include analyses of PH-associated biomarkers, right ventricular function and patient-reported outcomes. This is a protocol article and the results will be presented after data collection is completed. The POPLAR study will provide data that help better understand the pathophysiology of ILD-PH and improve the quality of life and outcome of patients with PH and/or ILD. Japan Registry of Clinical Trials: jRCT1010230018.

Recovery of optimal vitamin D improves responsiveness to phosphodiesterase-5 inhibitors therapy in pulmonary arterial hypertension

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): R.A. has received funding from the European Union’s Horizon 2020 research and innovation programme under Marie-Curie grant agreement Nº 847635. Introduction Vitamin D (vitD) deficiency is highly prevalent in patients with pulmonary arterial hypertension (PAH). Moreover, PAH-patients with lower levels of vitD have worse prognosis. We demonstrated that in animals with PAH and severe deficit of vitD, restoring vitD levels to an optimal range partially improves some pathophysiological features of PAH. Also, recent evidence suggests that vitD deficiency may cause insufficient response to phosphodiesterase-5 inhibitors (PDE5i), such as sildenafil, in some patients with PAH. Thus, in this study, we hypothesize that the recovery of optimal vitD levels in experimental PAH might help to improve responsiveness to PDE5i therapy. Methods Male Wistar rats were fed a vitD-free diet for five weeks and then received a single dose of Su5416 (20 mg/Kg) and were exposed to vitD-free diet and chronic hypoxia (10% O2) for three weeks to induce PAH. Following this, vitD deficient rats with PAH were housed in room air and divided into two groups: (a) daily tadalafil therapy (oral;10mg/kg) + continued vitD-free diet (n=9) or (b) daily tadalafil therapy (oral;10mg/kg) + single oral dose of 50,000 IU/Kg of vitD plus standard diet (n=9) for four weeks. Animals were then used for exercise capacity evaluation, invasive haemodynamic, pulmonary vascular analysis, and sample collection. Evolution of cardiac (dys)function was assessed by echocardiography. Results Recovering optimal vitD levels improved pulmonary endothelial function, measured by an increase in the endothelium-dependent vasodilator response to acetylcholine. It also increased the vasodilator response to sildenafil. Moreover, pulmonary small artery (<55 µm) remodeling was decreased in vitD-restored group, as measured by a decline in mean lumen/total ratio and mean medial thickness. In a morphometric analysis, vitD treatment attenuated increases in both right ventricle (RV) and right atrial hypertrophy, as well as the fulton index. VitD supplementation also improved the exercise capacity with increases seen in distance run, evaluated by endurance tests in a treadmill set. RV catheterization showed that vitD did not decreased the RV dysfunction, evaluated by end-systolic and end-diastolic pressure. Similar to the RV, no alterations were observed in pulmonary artery pressures. However, echocardiographic analysis revealed an improved pulmonary flow in the vitD-restored group, where pulmonary artery acceleration time normalized to ejection time ratio and pulmonary artery velocity-time integral were increased. It also improved tricuspid annular plane systolic excursion (TAPSE). Conclusion Altogether, these data suggest that in animals with PAH treated with tadalafil, restoring vitD levels to an optimal range improves some pathophysiological features of PAH. Therefore, in addition to recovery of optimal vitD status being indicated to restore calcium homeostasis in those PAH patients with severe deficiency, it might help to improve responsiveness to PDE5i.

PDZ-Binding Kinase, a Novel Regulator of Vascular Remodeling in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is high blood pressure in the lungs that originates from structural changes in small resistance arteries. A defining feature of PAH is the inappropriate remodeling of pulmonary arteries (PA) leading to right ventricle failure and death. Although treatment of PAH has improved, the long-term prognosis for patients remains poor, and more effective targets are needed. Gene expression was analyzed by microarray, RNA sequencing, quantitative polymerase chain reaction, Western blotting, and immunostaining of lung and isolated PA in multiple mouse and rat models of pulmonary hypertension (PH) and human PAH. PH was assessed by digital ultrasound, hemodynamic measurements, and morphometry. Microarray analysis of the transcriptome of hypertensive rat PA identified a novel candidate, PBK (PDZ-binding kinase), that was upregulated in multiple models and species including humans. PBK is a serine/threonine kinase with important roles in cell proliferation that is minimally expressed in normal tissues but significantly increased in highly proliferative tissues. PBK was robustly upregulated in the medial layer of PA, where it overlaps with markers of smooth muscle cells. Gain-of-function approaches show that active forms of PBK increase PA smooth muscle cell proliferation, whereas silencing PBK, dominant negative PBK, and pharmacological inhibitors of PBK all reduce proliferation. Pharmacological inhibitors of PBK were effective in PH reversal strategies in both mouse and rat models, providing translational significance. In a complementary genetic approach, PBK was knocked out in rats using CRISPR/Cas9 editing, and loss of PBK prevented the development of PH. We found that PBK bound to PRC1 (protein regulator of cytokinesis 1) in PA smooth muscle cells and that multiple genes involved in cytokinesis were upregulated in experimental models of PH and human PAH. Active PBK increased PRC1 phosphorylation and supported cytokinesis in PA smooth muscle cells, whereas silencing or dominant negative PBK reduced cytokinesis and the number of cells in the G2/M phase of the cell cycle. PBK is a newly described target for PAH that is upregulated in proliferating PA smooth muscle cells, where it contributes to proliferation through changes in cytokinesis and cell cycle dynamics to promote medial thickening, fibrosis, increased PA resistance, elevated right ventricular systolic pressure, right ventricular remodeling, and PH.

CXCR7 promotes pulmonary vascular remodeling via targeting p38/MMP2 pathway in pulmonary arterial hypertension.

A hallmark feature of pulmonary arterial hypertension (PAH) is the excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) in the pulmonary arteries. The exact role of C-X-C motif chemokine ligand 12 (CXCL12)/chemokine receptor type 7 (CXCR7) in the PASMCs remains unknown. This study was conducted to investigate CXCR7's role in p38/MMP2 pathway and its effect on PASMCs. In this study, we examined the expression profile of CXCL12/CXCR7 in both hypoxic rats and PASMCs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to measure the level of proliferation in PASMCs. Enzyme-linked immunosorbent assay (ELISA) and western blotting assays were applied to investigate the protein expression of the related molecules. We found that a high level of CXCR7 was correlated with remodeled pulmonary arterioles in hypoxic rats. Moreover, CXCR7 protein levels were significantly increased by the induction of CXCL12, indicating that the CXCL12-CXCR7 axis participates in PAH. During hypoxia-PAH, CXCR7 inhibition reduces right ventricular systolic pressure (RVSP), the Fulton index, and pulmonary arteriosclerosis remodeling. Further study indicated inhibition CXCR7 reduced PASMCs by downregulating MMP2, via p38 MAPK pathway. It was additionally found that CXCL12/CXCR7 stimulated the phosphorylation of the p38 MAPK pathway, which was a contributing factor to the decrease in MMP2 expression following preconditioning with SB203580, which inhibited p38 MAPK. In summary, these findings suggest that CXCL12/CXCR7 plays a critical role in PAH, the therapy of which can be developed further by targeting its potential targets.

In Vitro Experimental Approach for Studying Human Pulmonary Artery Smooth Muscle Cells and Endothelial Cells Proliferation and Migration.

Pulmonary arterial hypertension (PAH) is a severe vascular disease characterized by persistent precapillary pulmonary hypertension, leading to right heart failure and death. Despite intense research in the last decades, PAH remains an incurable disease with high morbidity and mortality. New directions and therapies to improve understanding and treatment of PAH are desperately needed. The pathological mechanisms leading to this fatal disorder remain mostly undetermined, although structural remodeling of the pulmonary vessels is known to be an early feature of PAH. Pulmonary vascular remodeling includes proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs). The use of in vitro approaches is useful to delineate the mechanisms involved in the pathogenesis of PAH and to identify new therapeutic strategies for PAH. In this chapter, we describe protocols for culturing and assessing proliferation and migration of human PASMCs and PAECs.

Clinical-radiological-pathological correlation in pulmonary arterial hypertension.

Pulmonary hypertension (PH) is defined by the presence of a mean pulmonary arterial pressure >20 mmHg. Current guidelines describe five groups of PH with shared pathophysiological and clinical features. In this paper, the first of a series covering all five PH classification groups, the clinical, radiological and pathological features of pulmonary arterial hypertension (PAH) will be reviewed. PAH may develop in the presence of associated medical conditions or a family history, following exposure to certain medications or drugs, or may be idiopathic in nature. Although all forms of PAH share common histopathological features, the presence of certain pulmonary arterial abnormalities, such as plexiform lesions, and extent of co-existing pulmonary venous involvement differs between the different subgroups. Radiological investigations are key to diagnosing the correct form of PH and a systematic approach to interpretation, especially of computed tomography, is essential.

The novel roles of YULINK in the migration, proliferation and glycolysis of pulmonary arterial smooth muscle cells: implications for pulmonary arterial hypertension

BackgroundAbnormal remodeling of the pulmonary vasculature, characterized by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) along with dysregulated glycolysis, is a pathognomonic feature of pulmonary arterial hypertension (PAH). YULINK (MIOS, Entrez Gene: 54468), a newly identified gene, has been recently shown to possess pleiotropic physiologic functions. This study aims to determine novel roles of YULINK in the regulation of PAH-related pathogenesis, including PASMC migration, proliferation and glycolysis.ResultsOur results utilized two PAH-related cell models: PASMCs treated with platelet-derived growth factor (PDGF) and PASMCs harvested from monocrotaline (MCT)-induced PAH rats (PAH-PASMCs). YULINK modulation, either by knockdown or overexpression, was found to influence PASMC migration and proliferation in both models. Additionally, YULINK was implicated in glycolytic processes, impacting glucose uptake, glucose transporter 1 (GLUT1) expression, hexokinase II (HK-2) expression, and pyruvate production in PASMCs. Notably, YULINK and GLUT1 were observed to colocalize on PASMC membranes under PAH-related pathogenic conditions. Indeed, increased YULINK expression was also detected in the pulmonary artery of human PAH specimen. Furthermore, YULINK inhibition led to the suppression of platelet-derived growth factor receptor (PDGFR) and the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K), and protein kinase B (AKT) in both cell models. These findings suggest that the effects of YULINK are potentially mediated through the PI3K-AKT signaling pathway.ConclusionsOur findings indicate that YULINK appears to play a crucial role in the migration, proliferation, and glycolysis in PASMCs and therefore positioning it as a novel promising therapeutic target for PAH.

Abstract 17276: NOTCH3-BMPR Interactions Drive Smooth Muscle Cell Proliferation and Medial Hyperplasia in Pulmonary Arterial Hypertension

Background: One of the characteristics of pulmonary arterial hypertension (PAH) is the proliferation of smooth muscle cells. In heritable PAH, aberrant BMPR2 signaling results in low levels of intracellular ID1. An important pathway involved in vascular smooth muscle cell proliferation and the development of non-heritable PAH is the NOTCH3-HES5 signaling pathway. Previous studies have demonstrated that HES-5 and ID-1 are peptides belonging to the basic helix-loop-helix family, and they act as transcriptional enhancers of cell cycle genes. Transcriptional enhancement or repression requires the heterodimerization of different HES and ID proteins. Hypothesis: We hypothesize that HES-5 binds to and degrades IDs in non-heritable cases of PAH. Methods: The half-life of ID proteins was assessed in human small pulmonary artery smooth muscle cells that either constitutively expressed or minimally expressed HES-5. In order to understand whether this effect was due to direct binding between HES-5 and ID1, co-immunoprecipitation experiments were performed. Immunofluorescent staining was used to detect the expression level of ID1 and HES-5. Proximity ligation assay (PLA) was utilized to examine of endogenous in-situ interaction of ID1-HES5. Results: We found that overexpression of HES-5 significantly diminished the half-life of ID1 and ID3, and had little effect on ID2. All three proteins localized to the nucleus of small pulmonary artery smooth muscle cells. Immunofluorescent staining confirmed elevated levels of HES and reduced levels of ID1 and ID3 in the medial layer of PAH vessels. By PLA assay, we show that HES-5 and ID1 as well as HES-5 and ID-3 physically associate with each other to the level of 40 nanometers. Conclusions: Constitutive NOTCH3 signaling and high intracellular HES-5 levels drive vascular smooth muscle cell proliferation in non-familial PAH by binding to and degrading ID intracellular proteins. Our study demonstrates cross-talk between the NOTCH3-pathway and the BMPR2 pathway in this disease, at the level of their downstream effectors: ID1 and HES-5. Further studies should shed light on how these two pathways control the PAH disease process.

Abstract 15826: Single-Cell Analysis of Right Ventricle Combined With AI: Implications for Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension (PAH) significantly compromises the functionality of the right ventricle (RV). Our recently established NFU1 mutation-based rat model spontaneously develops PAH and successfully recapitulates main features of human PAH, such as gender dimorphism, right ventricle (RV) hypertrophy and dysfunction with RV-pulmonary artery uncoupling. Objective: We aimed to discern unique transcriptional differences between in WT and NFU1 rats on the single cell level, which may shed light on potential therapeutic targets for RV hypertrophy in PAH. Methods: We performed a single-cell transcriptomics analysis of WT and NFU1 RV collected from WT and NFU1 G206C rats to determine potential targets for treating RV dysfunction. The single-cell data was processed, and cells were annotated. Differentially expressed (DE) genes in cell types between the WT and NFU1 were determined using a two-sided Wilcoxon rank sum test. Finally, PandaOmics AI was employed to select through RV transcriptomics data (Boucherat, 2022) and extract the top 300 human targets from our key gene findings in the rat model. Results: We identified several cell types in rat scRNA-seq data, among which cardiomyocytes and endothelial cells had the highest number of human-relevant rat targets. Endothelial cells had 6 targets, Hsp90aa1/b1, Fabp4, Fhl2, Tnni3, Atp2a2, Ndufa4. These genes can affect endothelial cell proliferation, vascular integrity, intracellular transport, and angiogenic phenotype. Cardiomyocytes had 24 identified targets responsible for increased mitochondrial metabolism (Ndufv1, Nme2, Mrpl15), calcium release and muscle contraction (Ryr2, S100a1, Atp2a2), and others. Conclusions: A distinct disparity is observed in the transcriptional landscape in RV in NFU1 model of PAH. This could either indicate an adaptive response by the RV to increased afterload or be tied to its distinctive embryological/developmental origin, morphology, and functional properties. Novel cell-type-specific potential targets responsible for RV hypertrophy and dysfunction in PAH were discovered.

Identification of monocyte-associated pathways participated in the pathogenesis of pulmonary arterial hypertension based on omics-data.

Pulmonary arterial hypertension (PAH) is one kind of chronic and uncurable diseases that can cause heart failure. Immune microenvironment plays a significant role in PAH. The aim of this study was to assess the role of immune cell infiltration in the pathogenesis of PAH.Differentially expressed genesbased on microarray data were enriched in several immune-related pathways. To evaluate the immune cell infiltration, based on the microarray data sets in the GEO database, we used both ssGSEA and the CIBERSORT algorithm. Additionally, single-cell RNA sequencing(scRNA-seq) data was used to further explicit the specific role and intercellular communications. Then receiver operating characteristiccurves and least absolute shrinkage and selection operatorwere used to discover and test the potential diagnostic biomarkers for PAH.Both the immune cell infiltration analyses based on the microarray data sets and the cell proportion in scRNA-seq data exhibited a significant downregulation in the infiltration of monocytes in PAH. Then, the intercellular communications showed that the interaction weighs of most immune cells, including monocytes changed between the control and PAH groups, and the ITGAL-ITGB2 and ICAM signaling pathways played critical roles in this process. In addition, ITGAM and ICAM2 displayed good diagnosis values in PAH. This study implicated that the change of monocyte was one of the key immunologic features of PAH. Monocyte-associated ICAM-1 and ITGAL-ITGB2 signaling pathways might be involved in the pathogenesis of PAH.

Clinical features of pulmonary arterial hypertension associated with systemic sclerosis.

Systemic sclerosis is an autoimmune disorder of the connective tissue characterized by disordered inflammation and fibrosis leading to skin thickening and visceral organ complications. Pulmonary involvement, in the form of pulmonary arterial hypertension and/or interstitial lung disease, is the leading cause of morbidity and mortality among individuals with scleroderma. There are no disease-specific therapies for pulmonary involvement of scleroderma, and pulmonary arterial hypertension in this cohort has typically been associated with worse outcomes and less clinical response to modern therapy compared to other forms of Group I pulmonary hypertension in the classification from the World Symposium on Pulmonary Hypertension. Ongoing research aims to delineate how pathologic microvascular remodeling and fibrosis contribute to this poor response and offer a window into future therapeutic targets.

Restoration of Foxp3+ Regulatory T Cells by HDAC-Dependent Epigenetic Modulation Plays a Pivotal Role in Resolving Pulmonary Arterial Hypertension Pathology.

Rationale: Immune dysregulation is a common feature of pulmonary arterial hypertension (PAH). Histone deacetylase (HDAC)-dependent transcriptional reprogramming epigenetically modulates immune homeostasis and is a novel disease-oriented approach in modern times. Objectives: To identify a novel functional link between HDAC and regulatory T cells (Tregs) in PAH, aiming to establish disease-modified biomarkers and therapeutic targets. Methods: Peripheral blood mononuclear cells were isolated from patients with idiopathic PAH (IPAH) and rodent models of pulmonary hypertension (PH): monocrotaline rats, Sugen5416-hypoxia rats, and Treg-depleted mice. HDAC inhibitor vorinostat (suberoylanilide hydroxamic acid, SAHA) was used to examine the immune modulatory effects invivo, ex vivo, and invitro. Measurements and Main Results: Increased HDAC expression was associated with reduced Foxp3+ Tregs and increased PD-1 (programmed cell death-1) signaling in peripheral blood mononuclear cells from patients with IPAH. SAHA differentially modified a cluster of epigenetic-sensitive genes and induced Foxp3+ Treg conversion in IPAH T cells. Rodent models recapitulated these epigenetic aberrations and T-cell dysfunction. SAHA attenuated PH phenotypes and restored FOXP3 transcription and Tregs in PH rats; interestingly, the effects were more profound in female rats. Selective depletion of CD25+ Tregs in Sugen5416-hypoxia mice neutralized the effects of SAHA. Furthermore, SAHA inhibited endothelial cytokine/chemokine release upon stimulation and subsequent immune chemotaxis. Conclusions: Our results indicated HDAC aberration was associated with Foxp3+ Treg deficiency and demonstrated an epigenetic-mediated mechanism underlying immune dysfunction in PAH. Restoration of Foxp3+ Tregs by HDAC inhibitors is a promising approach to resolve pulmonary vascular pathology, highlighting the potential benefit of developing epigenetic therapies for PAH.

Epidemiological and clinical characteristics of pulmonary arterial hypertension in Indian patients: A hospital-based observational study

Context: Pulmonary hypertension (PH) is a condition characterized by an increase in pulmonary artery pressure, leading to morbidity and poor survival. In India, the high prevalence of certain diseases contributes to the burden of PH. To address this, this study provides epidemiological data and clinical characteristics of pulmonary artery hypertension. Materials and Methods: A cross-sectional study was conducted at a tertiary cardiac care hospital, recruiting 964 patients with severe pulmonary arterial hypertension (PAH). Patient data were obtained through a detailed history and physical examination, including 12-lead electrocardiogram, two-dimensional echocardiography, coronary angiography, right heart catheterization, and hematological and serological investigations. Results: The majority of patients (28.94%) were in the age group of 31–40 years, with a female preponderance in PAH disease. Idiopathic PAH (IPAH) was the most common type, accounting for 69.78% of all cases. The most common comorbid conditions were hypertension (48.55%) and Type-2 diabetes mellitus (44.81%). Dyspnea on exertion (98.34%) and edema of extremities (91.18%) were the most common symptoms. The mean survival rate was 50.98 months, with Type 1 PAH having the worst survival rate of 47.56 months. The statistical analysis showed a significant association between smoking and PAH. Conclusion: This study provides epidemiological data and clinical characteristics of PAH patients in India, emphasizing the need for early diagnosis, prompt management, and smoking cessation programs. The high prevalence of IPAH and female preponderance was also observed in this study. These findings can help in the development of targeted interventions and management strategies for PH patients in India.

Copaiba oil improves pulmonary nitric oxide bioavailability in monocrotaline-treated rats.

Oxidative stress is involved in increased pulmonary vascular resistance (PVR) and right ventricular (RV) hypertrophy, characteristics of pulmonary arterial hypertension (PAH). Copaiba oil, an antioxidant compound, could attenuate PAH damage. This study's aim was to determine the effects of copaiba oil on lung oxidative stress, PVR, and mean pulmonary arterial pressure (mPAP) in the monocrotaline (MCT) model of PAH. Male Wistar rats (170g, n=7/group) were divided into four groups: control, MCT, copaiba oil, and MCT+copaiba oil (MCT-O). PAH was induced by MCT (60mg/kg i.p.) and, after 1 week, the treatment with copaiba oil (400mg/kg/day gavage) was started for 14 days. Echocardiographic and hemodynamic measurements were performed. RV was collected for morphometric evaluations and lungs and the pulmonary artery were used for biochemical analysis. Copaiba oil significantly reduced RV hypertrophy, PVR, mPAP, and antioxidant enzyme activities in the MCT-O group. Moreover, increased nitric oxide synthase and decreased NADPH oxidase activities were observed in the MCT-O group. In conclusion, copaiba oil was able to improve the balance between nitric oxide and reactive oxygen species in lungs and the pulmonary artery and to reduce PVR, which could explain a decrease in RV hypertrophy in this PAH model.

Phase 3 Anticancer Agent, RRx-001, Ameliorates Hypoxia-Induced Pulmonary Hypertension

Background: The hallmark features of pulmonary artery hypertension (PAH), for which hypoxia triggers, are vascular remodeling, elevated pulmonary blood pressure, oxidative stress, and right ventricular hypertrophy. RRx-001 is a minimally toxic Phase 3 anticancer agent with anti-oxidative, anti-inflammatory, nitric oxide-donating, and anti-proliferative properties. This study aimed to investigate the effect of RRx-001 on intermittent hypoxia-induced PAH in rats. Methods: Male Wistar rats (180-220 g) were divided into four groups (n=6 per group): normoxic control, hypoxic with vehicle treatment (2 weeks breathing an atmosphere containing 10% oxygen), hypoxic treated with oral endothelin-1 receptor inhibitor, bosentan, 50 mg/kg per day for 2 weeks during hypoxia and one intravenous dose of 5mg/kg RRx-001 given the day before the start of the hypoxia. After sacrifice, hearts and lungs were removed and harvested for analysis. Results: Both RRx-001 and bosentan treated animals, separately and to a similar degree, significantly attenuated hypoxia-induced increases in right ventricular systolic pressure and right ventricular hypertrophy compared to control animals. RRx-001 and bosentan, separately and to a similar degree, also significantly decreased pulmonary artery media thickness. RRx-001 treatment reduced vasocostriction of pulmonary arterioles and the wall thickness/external diameter ratio of the pulmonary arteries compared to vehicle treated animals. Conclusions: RRx-001 reduces right ventricular systolic pressure and pulmonary vascular remodeling in a rat model of PAH, potentially making it a new therapeutic option for this disease. The combination of bosentan and RRx-001 will be attempted as a next step. Commercial and private foundation grants This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.