Right ventricular (RV) function is critical to prognosis in all forms of pulmonary hypertension. Here we perform molecular phenotyping of RV remodeling by transcriptome analysis of RV tissue obtained from 40 individuals, and two animal models of RV dysfunction of both sexes. Our unsupervised clustering analysis identified ‘early’ and ‘late’ subgroups within compensated and decompensated states, characterized by the expression of distinct signaling pathways, while fatty acid metabolism and estrogen response appeared to underlie sex-specific differences in RV adaptation. The circulating levels of several extracellular matrix proteins deregulated in decompensated RV subgroups were assessed in two independent cohorts of individuals with pulmonary arterial hypertension, revealing that NID1, C1QTNF1 and CRTAC1 predicted the development of a maladaptive RV state, as defined by magnetic resonance imaging parameters, and were associated with worse clinical outcomes. Our study provides a resource for subphenotyping RV states, identifying state-specific biomarkers, and potential therapeutic targets for RV dysfunction.

Background: The mechanism of esophageal thermal injury (ETI; esophageal mucosal injury and periesophageal nerve injury leading to gastric hypomotility) remains unknown when using a high-power short-duration (HP-SD) setting. This study sought to evaluate the characteristics of esophageal injuries in atrial fibrillation ablation using a HP-SD setting. Methods: After exclusion of 5 patients with their esophagus at the right portion of left atrium and 21 patients with additional ablations such as box isolation and low voltage area ablation in left atrium posterior wall, 271 consecutive patients (62±10 years, 56 women) who underwent pulmonary vein isolation by radiofrequency catheter ablation were analyzed. In the 101 patients, a HP-SD setting at 45 to 50 W with an Ablation Index module was used (HP-SD group). In the remaining 170 patients before introduction of the HP-SD setting, a conventional power setting of 20 to 30 W with contact force monitoring was used (conventional group). We performed esophagogastroduodenoscopy after pulmonary vein isolation in all patients and investigated the incidence and characteristics of ETI. Results: Although the incidence of ETI was significantly higher in the HP-SD group compared with the conventional group (37% versus 22%, P =0.011), the prevalence of esophageal lesions did not differ between the groups (7% versus 8%). Multivariate logistic regression analysis revealed that the use of the HP-SD setting (odds ratio, 6.09, P <0.001), and the parameters that suggest anatomic proximity surrounding the esophagus, were independent predictors of ETI. However, the majority of ETI in the HP-SD group was gastric hypomotility, and the thermal injury was limited to the shallow layer of the periesophageal wall using the HP-SD setting. Conclusions: Although the use of the HP-SD setting was a strong predictor of ETI, it could avoid deeper thermal injuries that reach the esophageal mucosal layer.

Pulmonary hypertension (PH) is a progressive cardiopulmonary disease characterized by pulmonary arterial remodeling. Clonal somatic mutations including JAK2V617F, the most frequent driver mutation among myeloproliferative neoplasms, have recently been identified in healthy individuals without hematological disorders. Here, we reveal that clonal hematopoiesis with JAK2V617F exacerbates PH and pulmonary arterial remodeling in mice. JAK2V617F-expressing neutrophils specifically accumulate in pulmonary arterial regions, accompanied by increases in neutrophil-derived elastase activity and chemokines in chronic hypoxia-exposed JAK2V617F transgenic (JAK2^V617F) mice, as well as recipient mice transplanted with JAK2^V617F bone marrow cells. JAK2V617F progressively upregulates Acvrl1 (encoding ALK1) during the differentiation from bone marrow stem/progenitor cells peripherally into mature neutrophils of pulmonary arterial regions. JAK2V617F-mediated STAT3 phosphorylation upregulates ALK1-Smad1/5/8 signaling. ALK1/2 inhibition completely prevents the development of PH in JAK2^V617F mice. Finally, our prospective clinical study identified JAK2V617F-positive clonal hematopoiesis is more common in PH patients than in healthy subjects. These findings indicate that clonal hematopoiesis with JAK2V617F causally leads to PH development associated with ALK1 upregulation.

BACKGROUND: The immune systems and chronic inflammation are implicated in the pathogenesis of dilated cardiomyopathy (DCM) and heart failure. However, the significance of neutrophil extracellular traps (NETs) in heart failure remains to be elucidated. METHODS: We enrolled consecutive 62 patients with heart failure with idiopathic DCM who underwent endomyocardial biopsy. Biopsy specimens were subjected to fluorescent immunostaining to detect NETs, and clinical and outcome data were collected. Ex vivo and in vivo experiments were conducted. RESULTS: The numbers of NETs per myocardial tissue area and the proportion of NETs per neutrophil were significantly higher in patients with DCM compared with non-DCM control subjects without heart failure, and the numbers of NETs were negatively correlated with left ventricular ejection fraction. Patients with DCM with NETs (n=32) showed lower left ventricular ejection fraction and higher BNP (B-type natriuretic peptide) than those without NETs (n=30). In a multivariable Cox proportional hazard model, the presence of NETs was independently associated with an increased risk of adverse cardiac events in patients with DCM. To understand specific underlying mechanisms, extracellular flux analysis in ex vivo revealed that NETs-containing conditioned medium from wild-type neutrophils or purified NET components led to impaired mitochondrial oxygen consumption of cardiomyocytes, while these effects were abolished when PAD4 (peptidyl arginine deiminase 4) in neutrophils was genetically ablated. In a murine model of pressure overload, NETs in myocardial tissue were predominantly detected in the acute phase and persisted throughout the ongoing stress. Four weeks after transverse aortic constriction, left ventricular ejection fraction was reduced in wild-type mice, whereas PAD4-deficient mice displayed preserved left ventricular ejection fraction without inducing NET formation. CONCLUSIONS: NETs in myocardial tissue contribute to cardiac dysfunction and adverse outcomes in patients with heart failure with DCM, potentially through mitochondrial dysfunction of cardiomyocytes.

BACKGROUND: Pulmonary arterial hypertension (PAH) is characterized by obliterative vascular remodeling of the small pulmonary arteries (PAs) and progressive increase in pulmonary vascular resistance leading to right ventricular failure. Although several drugs are approved for the treatment of PAH, mortality rates remain high. Accumulating evidence supports a pathological function of integrins in vessel remodeling, which are gaining renewed interest as drug targets. However, their role in PAH remains largely unexplored. METHODS: The expression of the RGD (arginylglycylaspartic acid)–binding integrin α5β1 was assessed in PAs, PA smooth muscle cells, and PA endothelial cells from patients with PAH and controls using NanoString, immunoblotting, and Mesoscale Discovery assays. RNA sequencing was conducted to identify gene networks regulated by α5β1 inhibition in PAH PA smooth muscle cells. The therapeutic efficacy of α5β1 inhibition was evaluated using a novel small molecule inhibitor and selective neutralizing antibodies in Sugen/hypoxia and monocrotaline rat models, with validation by an external contract research organization. Comparisons were made against standard-of-care therapies (ie, macitentan, tadalafil) and sotatercept and efficacy was assessed using echocardiographic, hemodynamic, and histological assessments. Ex vivo studies using human precision-cut lung slices were performed to further assess the effects of α5β1 inhibition on pulmonary vascular remodeling. RESULTS: We found that the arginine-glycine-aspartate RGD-binding integrin α5β1 is upregulated in PA endothelial cells and PA smooth muscle cells from patients with PAH and remodeled PAs from animal models. Blockade of the integrin α5β1 or depletion of the α5 subunit downregulated FOXM1 (forkhead box protein M1)–regulated gene networks, resulting in mitotic defects and inhibition of the pro-proliferative and apoptosis-resistant phenotype of PAH cells. We demonstrated that α5β1 integrin blockade safely attenuates pulmonary vascular remodeling and improves hemodynamics and right ventricular function and matched or exceeded the efficacy of standard of care and sotatercept in multiple preclinical models. Ex vivo studies further validated its potential in reversing advanced remodeling in human precision-cut lung slices. CONCLUSIONS: These findings establish α5β1 integrin as a pivotal driver of PAH pathology and we propose its inhibition as a novel, safe, and effective therapeutic strategy for PAH.