Willems L, Camilleri E, Bosmans E
… +9 more, Verhaegen J, van Hylckama Vlieg A, Rosendaal FR, Delcroix M, Kurakula K, Goumans MTH, Cannegieter SC, Klok FA, Quarck R
Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but severe complication of pulmonary embolism (PE), yet its underlying mechanisms remain poorly understood. Peptidyl-prolyl cis/trans isomerase (Pin1), a re...Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but severe complication of pulmonary embolism (PE), yet its underlying mechanisms remain poorly understood. Peptidyl-prolyl cis/trans isomerase (Pin1), a regulatory enzyme involved in thrombosis, inflammation, and vascular remodeling, may contribute to pulmonary vascular disease. We investigated whether circulating Pin1 levels are associated with the risk of CTEPH and its severity. In this case-control study, we measured circulating Pin1 levels by ELISA and compared them across 329 patients with CTEPH, 350 patients after acute PE, and 350 healthy individuals. Associations between Pin1 levels and clinical parameters were assessed with multivariable regression, stratified by sex. Overall, circulating Pin1 levels did not differ between patients with CTEPH, patients after acute PE, and healthy individuals. However, male patients with CTEPH had higher Pin1 levels than the two control groups, while female patients with CTEPH had slightly lower levels than female healthy individuals. Elevated Pin1 levels were associated with improved hemodynamics and exercise capacity, lower N-terminal prohormone of brain natriuretic peptide, and increased probability of CTEPH in men. Among healthy individuals, circulating Pin1 levels varied based on age, sex, and history of cancer. In conclusion, circulating Pin1 did not distinguish between patients with CTEPH, acute PE or healthy individuals. Nonetheless, our results suggest a possible sex-specific association between circulating Pin1 levels and CTEPH. Although Pin1 is unlikely to serve as a standalone biomarker, it may reflect underlying sex-specific pathological mechanisms, and further investigation on its utility within multimodal strategies for early risk stratification of CTEPH is warranted.
Macitentan 10 mg and tadalafil 40 mg single-tablet combination therapy (M/T STCT) has been evaluated in the global A DUE study (NCT03904693). Here, we report the results of a subgroup analysis in participants from China....Macitentan 10 mg and tadalafil 40 mg single-tablet combination therapy (M/T STCT) has been evaluated in the global A DUE study (NCT03904693). Here, we report the results of a subgroup analysis in participants from China. This double-blind, active-controlled, Phase 3 A DUE study randomized patients with symptomatic pulmonary arterial hypertension (PAH) to receive M/T STCT, macitentan, or tadalafil depending on their baseline PAH treatment (treatment-naïve, endothelin receptor antagonist, or phosphodiesterase Type 5 inhibitor monotherapy). The primary end point was change in pulmonary vascular resistance (PVR) expressed as the ratio of geometric means (GMR) of Week 16 to baseline. A total of 187 patients were randomized, including 23 patients in China. PVR reduction was significantly greater with M/T STCT compared with macitentan (50%) and tadalafil (41%) (adjusted GMRs were 0.50; 95% confidence level [CL]: 0.35-0.72; = 0.0017 and 0.59; 95% CL: 0.43-0.80; = 0.0040, respectively) in Chinese patients. M/T STCT was well tolerated in Chinese patients; the safety profile was consistent with that of macitentan and tadalafil monotherapies, and that of the overall population. In conclusion, in Chinese patients with PAH, PVR was reduced with M/T STCT versus either monotherapy after 16 weeks of treatment; the safety profile of M/T STCT was in line with the known safety profile of the individual components and appeared consistent with the overall population, although data should be interpreted with caution due to the small sample size. Our findings support the use of M/T STCT for PAH in China. : ClinicalTrials.gov https://clinicaltrials.gov/ NCT03904693 (April 5, 2019).
Pulmonary arterial hypertension (PAH) is a fatal disease with limited available treatments and is characterized by pulmonary vascular remodeling. Substance P (SP) may be involved in vascular remodeling in patients with P...Pulmonary arterial hypertension (PAH) is a fatal disease with limited available treatments and is characterized by pulmonary vascular remodeling. Substance P (SP) may be involved in vascular remodeling in patients with PAH. However, the underlying mechanism is currently unknown. In this study, we found that plasma SP levels were elevated and correlated with pulmonary hemodynamic parameters in PAH patients. SP receptor inhibitors significantly suppressed pulmonary vascular remodeling and improved pulmonary circulation hemodynamics in PAH rats. Multiple omics analyses suggested that downregulation of Fibulin-2 (Fbln2) may play a role in promoting pulmonary vascular remodeling by SP. In addition, the downregulation of Fbln2 expression by SP was further verified by Western blot analysis and immunofluorescence. In vitro experiments showed that SP negatively regulated β-catenin expression by downregulating Fbln2 expression. Moreover, SP promoted the DNA methylation of Fbln2. A methylation inhibitor alleviated SP mediated low expression of Fbln2 and high expression of β-catenin. Overexpression of Fbln2 inhibited the proliferation and migration of pulmonary artery smooth muscle cells induced by SP. These data provide a novel mechanism through which SP promotes the proliferation and migration of PASMCs, leading to pulmonary hypertension and suggesting that Fbln2 is a potential therapeutic target for PAH.
Severe diffusion impairment in pulmonary arterial hypertension (PAH), particularly in idiopathic PAH (IPAH), has garnered considerable attention. However, comprehensive data on low diffusion capacity of the lungs for car...Severe diffusion impairment in pulmonary arterial hypertension (PAH), particularly in idiopathic PAH (IPAH), has garnered considerable attention. However, comprehensive data on low diffusion capacity of the lungs for carbon monoxide (DLCO) with preserved lung function remain limited in broader pulmonary hypertension (PH) cohorts. We analyzed patients with PH, preserved lung function, low DLCO, and available computed tomography (CT) scans. The analysis included 117 patients, with 34% cases of combined pulmonary fibrosis and emphysema (CPFE), 22% IPAH, 15% interstitial lung disease (ILD), 9% pulmonary veno-occlusive disease (PVOD), and 8% connective tissue disease (CTD). Based on hemodynamic and CT imaging features, the overall population could be broadly categorized into two phenotypic patterns. "Parenchymal Type" ( = 81; 69%), predominantly consisted of CPFE and ILD, with an average age of 69 ± 9 years, 89% male. The median mean pulmonary arterial pressure (mPAP) was 39 mmHg, and lung abnormalities observed included emphysema, interstitial fibrosis, and diffuse ground-glass opacities (GGO). "Vascular Type" ( = 36; 31%), mainly composed of PVOD and CTD cases. with average age of 52 ± 19 years, 64% female, median mPAP of 53 mmHg and centrilobular GGO (78%). IPAH patients were distributed across both phenotypic categories, exhibiting mixed characteristics of the "Parenchymal Type" and "Vascular Type". The 5-year survival rate for the overall patient cohort was 31%. In conclusion, PH patients with low DLCO and preserved lung function represent two distinct phenotypic patterns and are associated with a poor prognosis.
Kolaitis NA, Sahay S, Rosenzweig EB
… +11 more, Brown D, Hemnes A, Joseloff E, Meyer J, Pescatore KA, Rizzo A, Sood N, Stewart B, McLaughlin V, Williamson T, Klinger JR
The American Lung Association and Pulmonary Hypertension Association convened a scientific roundtable of pulmonary hypertension experts to discuss the latest recommendations from the European Guidelines for the Diagnosis...The American Lung Association and Pulmonary Hypertension Association convened a scientific roundtable of pulmonary hypertension experts to discuss the latest recommendations from the European Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension (PH) and from the 7th World Symposium on Pulmonary Hypertension (WSPH). The aim of the roundtable was to discuss changes that were made compared to earlier recommendations and guidelines set out by the European Society of Cardiology and the European Respiratory Society in 2015, the 6th World Symposium on Pulmonary Hypertension in 2018, and the CHEST Guideline on Therapy for Pulmonary Arterial Hypertension in 2019. The overall objectives were to: 1) Create an educational resource for providers that summarizes currently available PAH guidelines, 2) Provide an expert critique of current guidelines, outlining strengths and weaknesses and resolving differences where guidelines do not agree. 3) Provide guidance for the incorporation of the recently approved drug, sotatercept into current guidelines. An executive summary was drafted following the roundtable meeting on April 8, 2024, and revised by the panel in September 2024, following publication of the proceedings from the 7th WSPH held in Barcelona June 29-July 1, 2024. The Executive Summary reviews changes to the hemodynamic criteria for defining pre- and post-capillary PH, exercise-induced PH, and PH associated with lung disease. Recommendations are given for proper diagnosis and clinical classifications of the various forms of PH. The role of screening for PH in high-risk populations and the use of risk scores for disease stratification are discussed. Finally, treatment algorithms for managing pulmonary arterial hypertension, PH associated with lung disease, and chronic thromboembolic pulmonary hypertension are presented.
During the COVID-19 pandemic, Brazil was one of the most affected countries. Patients presented higher risk of acute venous thromboembolism (VTE), in particular, pulmonary embolism (PE). However, long-term implications o...During the COVID-19 pandemic, Brazil was one of the most affected countries. Patients presented higher risk of acute venous thromboembolism (VTE), in particular, pulmonary embolism (PE). However, long-term implications of these events remain unknown. A retrospective analysis from the FENIX study was conducted, and patients with COVID-19-related VTE during hospitalization were included. Further analysis, up to 6 months after the acute event, was performed exclusively in patients with PE. Persistence of dyspnea and exercise intolerance was evaluated through imaging, rest, and exercise functional tests. Cumulative incidence of VTE during hospitalization among COVID-19 survivors followed at the outpatient clinic was 17.7% ( = 75/423) and of acute PE was 9.9% ( = 42/423). Patients with PE were mostly male (66%), 56 ± 16 years old, and mainly classified as intermediate-low risk (74%). Dyspnea (mMRC≥ 1) up to 6 months of PE was present in 56% ( = 19/34), with a borderline association with parenchymal lung sequelae on chest CT scan ( = 0.069). Symptomatic patients upon follow-up presented lower FEV1 and FVC, as well as increased peak VD/VT ratio and ventilatory inefficiency. No signs of pulmonary hypertension (PH) were identified on echocardiogram (ECHO) and cardiopulmonary exercise testing (CPET). Persistence of dyspnea among post-PE related to COVID-19 was high. However, no cases of PH were found; follow-up findings may be related to pulmonary parenchymal and microvascular injury. Also, we cannot exclude association with long-COVID, in which pathophysiological mechanisms are multifactorial, involving chronic inflammatory changes and multiorgan dysfunction, highlighting the need for comprehensive evaluation of exercise intolerance through invasive CPET.
Pulmonary arterial hypertension (PAH) significantly impacts mortality and quality of life. Access to specialized care may differ between urban and rural patients, potentially influencing outcomes. This study compared the...Pulmonary arterial hypertension (PAH) significantly impacts mortality and quality of life. Access to specialized care may differ between urban and rural patients, potentially influencing outcomes. This study compared the clinical course and treatment patterns of PAH patients from urban and rural settings treated at a single comprehensive care center. Adult patients with WHO Group I PAH evaluated between August 2020 and August 2024 at the University of Utah Pulmonary Hypertension Comprehensive Care Center were prospectively enrolled in a program-specific registry. A total of 263 patients were categorized as urban or rural based on residential address. Baseline characteristics, diagnostics, treatments, and outcomes were compared. No significant differences were observed in baseline characteristics, 6-min walk distance (6MWD), right ventricular function, hemodynamics, or NT-proBNP levels. In-person and virtual clinic utilization were also similar. However, among patients receiving triple therapy, rural patients were significantly more likely to receive inhaled treprostinil as the prostacyclin component ( = 0.03). In a subset of patients ( = 146), REVEAL Lite 2 scores were available at baseline and follow-up. Risk distributions and mean scores were similar at each time point. However, urban patients showed significant improvement in REVEAL risk category over time ( = 0.007), while no significant change occurred in rural patients. These findings suggest that although care delivery appeared comparable across settings, differences in treatment selection and risk trajectories emerged over time. Further investigation is needed to understand the drivers of these differences and their implications for disease management and progression.
Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by elevated pulmonary vascular resistance. Despite recent advances, early diagnosis remains challenging due to nonspecific symptoms. By...Pulmonary arterial hypertension (PAH) is a life-threatening condition characterized by elevated pulmonary vascular resistance. Despite recent advances, early diagnosis remains challenging due to nonspecific symptoms. By utilizing RNA sequencing (RNA-seq) data from the GEO database, we conducted bioinformatics analyses to identify potential diagnostic biomarkers. Differentially expressed genes (DEGs) were screened in blood from PAH patients, followed by functional enrichment and protein-protein interaction (PPI) network analyses. Thirteen overlapping DEGs were identified, which were enriched in erythrocyte development, heme biosynthesis, and chloride transport. Five hub genes (SLC4A1, AHSP, ALAS2, FECH, and CA1), exhibited strong diagnostic potential, with an area under the curve (AUC) ≥ 0.7 in training datasets (GSE38267, GSE22356). External validation using datasets GSE33463 and GSE117261 confirmed their efficacy in blood samples, although AHSP showed reduced performance in lung tissue. Experimental validation in hypoxic human pulmonary artery smooth muscle cells (hPASMCs) supported the bioinformatics findings. These results underscore SLC4A1, AHSP, ALAS2, FECH, and CA1 as promising noninvasive diagnostic biomarkers for PAH, linking transcriptional dysregulation to clinical application.
Patients with Eisenmenger syndrome (ES) are at increased risk of thrombotic events, especially in pulmonary vessels. However, both the prevalence and risk factors of pulmonary arterial thrombosis (PAT) have been varied g...Patients with Eisenmenger syndrome (ES) are at increased risk of thrombotic events, especially in pulmonary vessels. However, both the prevalence and risk factors of pulmonary arterial thrombosis (PAT) have been varied greatly. In this study we sought to examine the prevalence of PAT in adult patients with ES and to identify risk factors. A cross-section descriptive study examining 57 adult patients with ES. All patients underwent computed tomography pulmonary angiography (CTPA) and echocardiography. Echocardiographic parameters and laboratory data were analysed from 57 patients. PAT prevalence was 22.8% (13/57), with all thrombi localized to dilated proximal pulmonary arteries (main pulmonary artery diameter: 52.6 ± 6.2 vs. 40.1 ± 6.9 mm in non-thrombosis group, < 0.05). Thrombotic patients exhibited higher D-dimer (0.7 [IQR: 0.5-1.9] vs. 0.3 [IQR: 0.2-0.6] mg/L, < 0.05) and NT-proBNP levels (2561.0 [1389.0-5904.3] vs. 695.4 [180.6-2452.7] pg/mL, < 0.05), alongside reduced right ventricular fractional area change (RV FAC: 23.9 ± 5.5% vs. 32.4 ± 10.0%, < 0.05). No differences were observed in age, oxygen saturation, hemoglobin, coagulation profiles, or right heart catheterization parameters (mPAP, PVR, mRAP). PAT affects nearly one-quarter of ES patients, routine CTPA screening should be considered even in asymptomatic cases. The lack of association with conventional risk factors underscores the need for thrombosis risk stratification integrating anatomical and biomarker criteria.
Pulmonary hypertension due to interstitial lung disease (PH-ILD) is associated with high morbidity and mortality. Real-world patients initiating inhaled treprostinil are not well-characterized. This retrospective cohort...Pulmonary hypertension due to interstitial lung disease (PH-ILD) is associated with high morbidity and mortality. Real-world patients initiating inhaled treprostinil are not well-characterized. This retrospective cohort study aimed to evaluate healthcare resource utilization in patients with PH-ILD who initiated treatment with inhaled treprostinil vs patients who remained untreated. Adult patients diagnosed with PH-ILD were indexed on initiation of inhaled treprostinil and patients who remained untreated were indexed on first observed PH diagnosis (31 March 2021-30 September 2024). Patients were excluded if they were ever treated with any pulmonary arterial hypertension therapy. Inhaled treprostinil patients were matched to up to four untreated patients. All-cause per-patient per-month (PPPM) hospitalizations and ICU-related hospitalizations were the primary outcomes of interest. 294 patients treated with inhaled treprostinil and 736 untreated patients were identified. Mean all-cause PPPM hospitalizations remained unchanged in the pre-index vs post-index periods in the inhaled treprostinil cohort (0.11 vs 0.12; = 0.42) but significantly increased in untreated patients (0.12 vs 0.23; < 0.01). ICU utilization also remained unchanged in the pre-index vs post-index periods for the inhaled treprostinil cohort (0.06 vs 0.07; = 0.11) compared to the untreated cohort (0.06 vs 0.13; < 0.01). Untreated patients had significantly higher post-index PPPM hospitalizations ( < 0.01) and ICU utilization ( < 0.01) compared to inhaled treprostinil patients. Patients who initiated inhaled treprostinil had a 30% decreased risk of hospitalization compared to untreated patients (relative risk: 0.70; 95% CI: 0.59-0.83; < 0.01). Among real-world patients with PH-ILD, treatment with inhaled treprostinil is associated with fewer all-cause hospitalizations and ICU-related hospitalizations compared to untreated patients with PH-ILD.
Pulmonary hypertension (PH) is a common complication in interstitial lung disease (ILD), but the additional burden it imposes on patients and healthcare systems is not well characterized. This retrospective analysis of c...Pulmonary hypertension (PH) is a common complication in interstitial lung disease (ILD), but the additional burden it imposes on patients and healthcare systems is not well characterized. This retrospective analysis of claims data from the US Merative MarketScan database assessed hospitalization rates and costs over 2 years in patients with connective tissue disease-related ILD (CTD-ILD) and non-CTD-ILD with or without PH (between January 2017 and December 2019). Index was the date of first ILD claim; baseline was the 12-month preindex period. In total, 16,129 patients with non-CTD-ILD (1502 [9%] with PH) and 4545 patients with CTD-ILD (663 [15%] with PH) were identified. A higher proportion of patients with non-CTD-ILD with PH, compared with patients without PH, had all-cause and heart failure (HF)-related hospitalizations during baseline (all-cause, 37.0% vs. 22.3%; HF-related, 14.2% vs. 3.1%), 0-12 months (62.4% vs. 43.0%; 29.0% vs. 7.0%), and 13-24 months (44.7% vs. 18.3%; 21.5% vs. 3.2%) follow-up ( < 0.0001 for all). A significantly higher proportion of patients with CTD-ILD with PH, compared with patients without PH, had all-cause and HF-related hospitalizations during baseline (all-cause: 30.0% vs. 20.6%; HF-related: 9.1% vs. 1.9%), 0-12 months (41.9% vs. 29.1%; 15.5% vs. 3.9%), and 13-24 months (37.9% vs. 18.9%; 13.9% vs. 2.5%) follow-up ( < 0.0001 for all). In both cohorts, total all-cause and HF-related costs were significantly higher in patients with PH at baseline, 0-12 months, and 13-24 months follow-up ( < 0.05 for all). PH substantially increased hospitalization risks and costs in both types of ILD, underscoring the importance of improving outcomes in patients with ILD-PH.
Pulmonary endarterectomy (PEA) is a highly effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH). However, persistent or recurrent pulmonary hypertension (persistent/recurrent PH) following surger...Pulmonary endarterectomy (PEA) is a highly effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH). However, persistent or recurrent pulmonary hypertension (persistent/recurrent PH) following surgery can adversely impact patients' outcomes. This study investigated the predictive value of preoperative SPECT ventilation/perfusion (V/Q) imaging for post-PEA persistent/recurrent PH. Between 2016 and 2022, CTEPH patients at our hospital underwent PEA after right heart catheterization (RHC) and SPECT V/Q imaging and were followed for 2 years. Postoperative mean pulmonary artery pressure (mPAP) ≥ 25 mmHg indicates persistent/recurrent PH. Correlations were explored between the occurrence of postoperative persistent/recurrent PH and preoperative parameters, including systolic pulmonary artery pressure (sPAP), mPAP, pulmonary vascular resistance (PVR), and parameters of the SPECT V/Q scan. Seventy-four patients were enrolled, including 52 males (71.6%). Seventeen patients (23%) developed persistent/recurrent PH within 2-80 weeks after surgery. The persistent/recurrent PH and non-persistent/recurrent PH groups exhibited statistically significant preoperative differences in preoperative mPAP, sPAP, PVR, Begic's score, and V/Q mismatched volume percentage ( < 0.05 for all). ROC curve analysis identified the optimal cut-off values: mPAP-44.5 mmHg, sPAP-79.5 mmHg, PVR-944 dyn × s × cm, Begic's score-16.5, and V/Q mismatched percentage-35.58%. Cox regression analysis showed that preoperative mPAP and V/Q mismatched percentage were significant predictors of persistent/recurrent PH-free survival time, with relative hazards of 3.29 (95% CI: 1.08-10.01) ( = 0.036) and 3.94 (95% CI: 1.25-12.42) ( = 0.019), respectively. These findings indicate that metrics derived from SPECT V/Q scans can effectively stratify post-PEA patients by the risk of persistent/recurrent PH. Quantitative parameters could provide complementary information that enhances predictive accuracy of postoperative persistent/recurrent PH at the individual level. This may support the optimization of clinical management strategies, particularly by guiding patient-specific therapeutic interventions, such as balloon pulmonary angioplasty for patients with persistent/recurrent PH after PEA.
Right ventricular (RV) dysfunction is a critical yet often underrecognized determinant of prognosis in patients with advanced interstitial lung disease (ILD) undergoing lung transplant evaluation. The tricuspid annular p...Right ventricular (RV) dysfunction is a critical yet often underrecognized determinant of prognosis in patients with advanced interstitial lung disease (ILD) undergoing lung transplant evaluation. The tricuspid annular plane systolic excursion to pulmonary arterial systolic pressure (TAPSE/PASP) ratio has emerged as a promising noninvasive echocardiographic surrogate of RV-pulmonary arterial (RV-PA) coupling, offering a dynamic estimate of RV function relative to afterload. In this single-center retrospective cohort study, we assessed the prognostic association of the TAPSE/PASP ratio in 65 lung transplant candidates with advanced ILD. All patients underwent comprehensive transthoracic echocardiography and right heart catheterization as part of pre-transplant evaluation. The primary endpoint was a composite of all-cause mortality or lung transplantation. Over a median follow-up of 24 months, 33 patients (50.8%) reached this endpoint. Receiver operating characteristic (ROC) curve analysis identified an optimal TAPSE/PASP cutoff value of 0.55 (AUC: 0.763, < 0.001), with a sensitivity of 70% and specificity of 75% for predicting adverse outcomes. Patients with TAPSE/PAS < 0.55 exhibited significantly worse transplant-free survival (log-rank = 0.0057), more pronounced RV structural and functional impairment, and elevated pulmonary vascular resistance. In multivariable Cox regression analysis, TAPSE/PASP was the sole independent predictor of the primary outcome (HR: 0.09, = 0.01). These findings suggest that the TAPSE/PASP ratio may constitute a feasible and reproducible noninvasive surrogate of RV-pulmonary arterial uncoupling and could facilitate the identification of high-risk individuals among lung transplant candidates with advanced interstitial lung disease. However, in light of the retrospective and single-center nature of this study, the results should be interpreted with caution as hypothesis-generating, and further validation in large-scale, prospective, multicenter cohorts is warranted.
Idiopathic Pulmonary fibrosis (IPF) is a debilitating lung condition marked by chronic progression and reduced lung function. This study aimed to explore the functional role and regulatory mechanism of circular RNA circ_...Idiopathic Pulmonary fibrosis (IPF) is a debilitating lung condition marked by chronic progression and reduced lung function. This study aimed to explore the functional role and regulatory mechanism of circular RNA circ_0044226 in the pathogenesis of pulmonary fibrosis. The expression of circ_0044226 was analyzed in peripheral blood and TGF-β1-stimulated RLE-6TN cells using qRT-PCR. The cellular location of circ_0044226 was analyzed using FISH. The expression levels of circ_0044226 and METTL3 were evaluated in cells and clinical samples. Protein levels of GPX4 and FTH1 were examined using Western blot, while the levels of MDA, Fe and ROS were determined using commercial kits. The association of circ_0044226 with m6A modifications was validated by Methylated-RNA immunoprecipitation assay (MeRIP), RNA pulldown, RIP and dot blot assay. Finally, a Bleomycin (BLM) treated rat model was also utilized to verify the function of circ_0044226 in pulmonary fibrosis. The primary localization of circ_0044226 was within the cytoplasm and was found to be upregulated in blood samples from IPF patients and TGF-β1-treated RLE-6TN cells. Knockdown of circ_0044226 reduced the accumulation of free iron and MDA, and suppressed α-SMA and FN1 in TGF-β1-induced cells. Furthermore, METTL3 mediated the m6A modification of circ_0044226. Downregulation of METTL3 mitigated ferroptosis by inhibiting hsa_circ_0044226. The rat pulmonary fibrosis model further demonstrated that METTL3 knockdown alleviated pulmonary fibrosis by blocking ferroptosis through circ_0044226. Our findings demonstrated that targeting the METTL3/circ_0044226 axis attenuated pulmonary fibrosis by inhibiting ferroptosis in the studied models.
The resistance-compliance (RC) relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance (PAC) provides an integrative measure of global right ventricular (RV) afterload. However, debate...The resistance-compliance (RC) relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance (PAC) provides an integrative measure of global right ventricular (RV) afterload. However, debate persists regarding the clinical utility of PAC calculated using the empiric formula (PAC), and the ideal method for calculating PAC. We analysed haemodynamic and pulmonary pressure waveform data from 156 patients with pulmonary hypertension (PH). PAC was calculated using three methods: PAC, as well as two established waveform analysis methods, area-under-the-curve (PAC), and diastolic decay (PAC). Generalized linear mixed models were used to evaluate the relationship between PVR and PAC across these three methods. Model performance was assessed using Akaike and Bayesian Information Criteria (AIC/BIC). The diagnostic performance of each method was evaluated using ROC analysis. Cox regression was applied to assess the association with long term mortality. All three PAC methods demonstrated a strong inverse hyperbolic correlation with PVR. PAC provided stronger model performance (AIC -504.3; ² = 0.968), and best discriminated PH subtypes (AUC = 0.91), outperforming PAC (AUC = 0.88) and PAC (AUC = 0.75). PAC was also a stronger predictor of mortality than PAC, PAC or PVR (c-statistic = 0.747, compared to 0.737, 0.709 and 0.741 respectively). PAC is a robust and accessible method for assessing the pulsatile component of RV loading. This study supports its use as a physiologically meaningful parameter that together with PVR provides a comprehensive estimation of global RV afterload.