A correlated light and electron microscopy approach to study the subcellular localization of phosphorylated vimentin in human lung tissue.

Correlative microscopy is an important approach for bridging the resolution gap between fluorescence light and electron microscopy. Here, we describe a fast and simple method for correlative immunofluorescence and immunogold labeling on the same section to elucidate the localization of phosphorylated vimentin (P-Vim), a robust feature of pulmonary vascular remodeling in cells of human lung small arteries. The lung is a complex, soft and difficult tissue to prepare for transmission electron microscopy (TEM). Detailing the molecular composition of small pulmonary arteries (<500µm) would be of great significance for research and diagnostics. Using the classical methods of immunochemistry (either hydrophilic resin or thin cryosections), is difficult to locate small arteries for analysis by TEM. To address this problem and to observe the same structures by both light and electron microscopy, correlative microscopy is a reliable approach. Immunofluorescence enables us to know the distribution of P-Vim in cells but does not provide ultrastructural detail on its localization. Labeled structures selected by fluorescence microscope can be identified and further analyzed by TEM at high resolution. With our method, the morphology of the arteries is well preserved, enabling the localization of P-Vim inside pulmonary endothelial cells. By applying this approach, fluorescent signals can be directly correlated to the corresponding subcellular structures in areas of interest.

Delayed Diagnosis of Pulmonary Artery Thrombosis in a Patient Undergoing Mitral Valve Replacement.

ABSTRACT: The occurrence of pulmonary artery thrombus in association with rheumatic mitral stenosis is a rare complication. Pulmonary artery thrombus formation may worsen pulmonary artery pressures, and this may precipitate acute right heart failure. The possible mechanisms behind pulmonary artery thrombus formation during mitral valve replacement surgery could be acute coagulopathy following surgery, the presence of chronic pulmonary thromboembolism, or chronic atrial fibrillation. We report an unusual case of pulmonary artery thrombus in a patient with rheumatic MS which was diagnosed with transoesophageal echocardiography after MVR.

Pulmonary arteries in coelacanths shed light on the vasculature evolution of air-breathing organs in vertebrates.

To date, the presence of pulmonary organs in the fossil record is extremely rare. Among extant vertebrates, lungs are described in actinopterygian polypterids and in all sarcopterygians, including coelacanths and lungfish. However, vasculature of pulmonary arteries has never been accurately identified neither in fossil nor extant coelacanths due to the paucity of fossil preservation of pulmonary organs and limitations of invasive studies in extant specimens. Here we present the first description of the pulmonary vasculature in both fossil and extant actinistian, a non-tetrapod sarcopterygian clade, contributing to a more in-depth discussion on the morphology of these structures and on the possible homology between vertebrate air-filled organs (lungs of sarcopterygians, lungs of actinopterygians, and gas bladders of actinopterygians).

Assessment of pulmonary vascular anatomy: comparing augmented reality by holograms versus standard CT images/reconstructions using surgical findings as reference standard.

BACKGROUND: We compared computed tomography (CT) images and holograms (HG) to assess the number of arteries of the lung lobes undergoing lobectomy and assessed easiness in interpretation by radiologists and thoracic surgeons with both techniques. METHODS: Patients scheduled for lobectomy for lung cancer were prospectively included and underwent CT for staging. A patient-specific three-dimensional model was generated and visualized in an augmented reality setting. One radiologist and one thoracic surgeon evaluated CT images and holograms to count lobar arteries, having as reference standard the number of arteries recorded at surgery. The easiness of vessel identification was graded according to a Likert scale. Wilcoxon signed-rank test and κ statistics were used. RESULTS: Fifty-two patients were prospectively included. The two doctors detected the same number of arteries in 44/52 images (85%) and in 51/52 holograms (98%). The mean difference between the number of artery branches detected by surgery and CT images was 0.31 ± 0.98, whereas it was 0.09 ± 0.37 between surgery and HGs (p = 0.433). In particular, the mean difference in the number of arteries detected in the upper lobes was 0.67 ± 1.08 between surgery and CT images and 0.17 ± 0.46 between surgery and holograms (p = 0.029). Both radiologist and surgeon showed a higher agreement for holograms (κ = 0.99) than for CT (κ = 0.81) and found holograms easier to evaluate than CTs (p < 0.001). CONCLUSIONS: Augmented reality by holograms is an effective tool for preoperative vascular anatomy assessment of lungs, especially when evaluating the upper lobes, more prone to anatomical variations. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04227444 RELEVANCE STATEMENT: Preoperative evaluation of the lung lobe arteries through augmented reality may help the thoracic surgeons to carefully plan a lobectomy, thus contributing to optimize patients' outcomes. KEY POINTS: • Preoperative assessment of the lung arteries may help surgical planning. • Lung artery detection by augmented reality was more accurate than that by CT images, particularly for the upper lobes. • The assessment of the lung arterial vessels was easier by using holograms than CT images.

Pulmonary artery sarcoma affecting the pulmonary valve mistaken as pulmonary vasculitis: a case report and comparative literature review.

Pulmonary arterial sarcomas (PAS) are rare aggressive tumours occurring mainly in the pulmonary trunk. We report a case of PAS involving the pulmonary trunk wall and valve, with uniform wall thickening which represents an atypical imaging manifestation of this tumour. A 63-year-old male presented with vague respiratory symptoms with rapid progression. CTPA showed low density filling defects in both pulmonary arteries and PET scan showed increased uptake in the pulmonary trunk, which along with raised ESR suggested Pulmonary Vasculitis. Echo imaging showed Right ventricular hypertrophy and pulmonary stenosis. Response to steroid therapy was minimal and his symptoms worsened. A referral for second opinion was made and he was diagnosed with PAS. He underwent Pulmonary thromboendarterectomy with Pulmonary valve replacement. Post-operative histopathology confirmed the diagnosis. PAS is rare and frequently misdiagnosed. Surgical resection is not curative, but together with chemotherapy can prolong survival.

Continuous heart monitoring to evaluate treatment effects in pulmonary hypertension.

BACKGROUND: The treatment of pulmonary hypertension (PH) has improved rapidly in recent decades. There is increasing evidence to support the role of early intervention and treatment in affecting clinical outcomes in PH. OBJECTIVES: To assess treatment effects before and after the escalation of specific PH treatments using continuous heart monitoring with a Reveal LINQ loop recorder. METHODS: Patients were compared before and after treatment escalation. Treatment escalation was defined as an additional pulmonary arterial hypertension (PAH) drug, pulmonary endarterectomy, percutaneous balloon angioplasty or bilateral lung transplantation. Specifically, changes in heart rate variability (HRV), heart rate (HR) and physical activity were assessed. RESULTS: In this prospective study, 41 patients (27 with PAH and 14 with chronic thromboembolic pulmonary hypertension (CTEPH)) were enrolled. Among them, 15 (36.6%) patients underwent PH treatment escalation. Prior to escalation, patients were monitored for a median of 100 (range: 68-100) days and after therapy escalation for a median duration of 165 (range: 89-308) days. In the escalation group, there was a significant increase in HRV, physical activity indexed by daytime HR and a significant decrease in nighttime HR assessed at baseline and after treatment escalation in both the PAH and CTEPH groups. This was paralleled by significant improvements in WHO functional class, 6-min walking distance and N-terminal pro-b-type natriuretic peptide. CONCLUSIONS: This is the first study to demonstrate an association between specific PH therapies and changes in HRV, HR nighttime and physical activity. This indicates the potential of continuous monitoring in the evaluation of treatment effects in PH.

Nexplanonectomy-the surgical removal of an embolized implanted contraceptive device: a case report and review of the literature.

BACKGROUND: Nexplanon implants are a common hormonal contraceptive modality. Though rare, these devices can embolize into the injured wall of the basilic vein, through the right heart, and finally wedge itself into a pulmonary artery. With adherence to the arterial wall over time, it becomes less amenable to endovascular retrieval. Patients may present with symptoms mimicking a pulmonary embolism, or without any symptoms at all. In asymptomatic cases, endovascular retrieval and/or surgery is required when patients wish to begin having children prior to biological inactivity. The current literature showed as little as nine case reports detailing lung tissue removal in the aim of reversing a patient's implanted contraceptive device. CASE PRESENTATION: A 22-year-old asymptomatic active-duty Caucasian female presented for elective outpatient Nexplanon removal. The suspicion of possible implant migration arose when it was discovered to be non-palpable in her left arm. After plain film x-rays failed to localize the implant, a chest x-ray and follow-up Computed Tomography (CT) scan revealed that the Nexplanon had migrated to a distal branch of the left pulmonary artery. Due to the patient's strong desires to begin having children, the decision was made for removal. Initial endovascular retrieval failed due to Nexplanon encapsulation within the arterial wall. Ultimately, the patient underwent a left video-assisted thoracoscopic surgery (VATS) for exploration and left lower lobe basilar S7-9 segmentectomy, which successfully removed the Nexplanon. CONCLUSIONS: Implanted contraceptive devices can rarely result in migration to the pulmonary vasculature. These radiopaque devices are detectable on imaging studies if patients and clinicians are unable to palpate them. An endovascular approach should be considered first to spare lung tissue and avoid chest-wall incisions, but can be complicated by encapsulation and adherence to adjacent tissue. A VATS procedure with single-lung ventilation via a double-lumen endotracheal tube allows surgeons to safely operate on an immobilized lung while anesthesiologists facilitate single-lung ventilation. This patient's case details the uncommon phenomenon of Nexplanon migration, and the exceedingly rare treatment resolution of lung resection to remove an embolized device.

CircST6GAL1 knockdown alleviates pulmonary arterial hypertension by regulating miR-509-5p/multiple C2 and transmembrane domain containing 2 axis.

BACKGROUND: Hypertension is a main contributing factor of cardiovascular diseases; deregulated circular RNAs are involved in the pathogenesis of pulmonary arterial hypertension (PAH). Herein, we evaluated the function and mechanism of circST6GAL1 in PAH process. METHODS: Human pulmonary artery smooth muscle cells (HPASMCs) were cultured in hypoxic environment for functional analysis. The cell counting kit-8, 5-ethynyl-2'-deoxyuridine, wound healing, and flow cytometry assays were used to investigate cell proliferation, migration, and apoptosis. qRT-PCR and Western blotting analyses were used for level measurement of genes and proteins. The binding between miR-509-5p and circST6GAL1 or multiple C2 and transmembrane domain containing 2 (MCTP2) was analyzed by dual-luciferase reporter, RNA immunoprecipitation, and pull-down assays. The monocrotaline (MCT)-induced PAH mouse models were established for in vivo assay. RESULTS: CircST6GAL1 was highly expressed in PAH patients and hypoxia-induced HPASMCs. Functionally, circST6GAL1 deficiency reversed hypoxia-induced proliferation and migration, as well as apoptosis arrest in HPASMCs. Mechanistically, circST6GAL1 directly targeted miR-509-5p, and MCTP2 was a target of miR-509-5p. Rescue assays showed that the regulatory effects of circST6GAL1 deficiency on hypoxia-induced HPASMCs were abolished. Moreover, forced expression of miR-509-5p suppressed HPASMC proliferation and migration and induced cell apoptosis under hypoxia stimulation, while these effects were abolished by MCTP2 overexpression. Moreover, circST6GAL1 silencing improved MCT-induced pulmonary vascular remodeling and PAH. CONCLUSION: CircST6GAL1 deficiency reversed hypoxia-induced proliferation and migration, as well as apoptosis arrest in HPASMCs, and alleviated pulmonary vascular remodeling in MCT-induced PAH mouse models through the miR-509-5p/MCTP2 axis, indicating a potential therapeutic target for PAH.

Atrial Arrhythmias Following Pulmonary Thromboendarterectomy: A Comprehensive Review Of Current Literature.

Chronic thromboembolic pulmonary hypertension (CTEPH) presents as a progressive vascular condition arising from previous episodes of acute pulmonary embolism, contributing to the development of pulmonary hypertension (PH). Pulmonary thromboendarterectomy (PTE) is the gold-standard surgical treatment for CTEPH; however, it may be associated with postoperative sequelae, including atrial arrhythmias (AAs). This comprehensive literature review explores the potential mechanisms for PTE-induced AAs with emphasis on the role of PH-related atrial remodelling and the predisposing factors. The identified preoperative predictors for AAs include advanced age, male gender, elevated resting heart rate, previous AAs, and baseline elevated right atrial pressure. Furthermore, we explore the available data on the association between post-PTE pericardial effusions and the development of AAs. Lastly, we briefly discuss the emerging role of radiomic analysis of epicardial adipose tissue as an imaging biomarker for predicting AAs.

N6-methyladenosine modification of KLF2 may contribute to endothelial-to-mesenchymal transition in pulmonary hypertension.

BACKGROUND: Pulmonary hypertension (PH) is a progressive disease characterized by pulmonary vascular remodeling. Increasing evidence indicates that endothelial-to-mesenchymal transition (EndMT) in pulmonary artery endothelial cells (PAECs) is a pivotal trigger initiating this remodeling. However, the regulatory mechanisms underlying EndMT in PH are still not fully understood. METHODS: Cytokine-induced hPAECs were assessed using RNA methylation quantification, qRT-PCR, and western blotting to determine the involvement of N6-methyladenosine (m6A) methylation in EndMT. Lentivirus-mediated silencing, overexpression, tube formation, and wound healing assays were utilized to investigate the function of METTL3 in EndMT. Endothelial-specific gene knockout, hemodynamic measurement, and immunostaining were performed to explore the roles of METTL3 in pulmonary vascular remodeling and PH. RNA-seq, RNA Immunoprecipitation-based qPCR, mRNA stability assay, m6A mutation, and dual-luciferase assays were employed to elucidate the mechanisms of RNA methylation in EndMT. RESULTS: The global levels of m6A and METTL3 expression were found to decrease in TNF-α- and TGF-ß1-induced EndMT in human PAECs (hPAECs). METTL3 inhibition led to reduced endothelial markers (CD31 and VE-cadherin) and increased mesenchymal markers (SM22 and N-cadherin) as well as EndMT-related transcription factors (Snail, Zeb1, Zeb2, and Slug). The endothelial-specific knockout of Mettl3 promoted EndMT and exacerbated pulmonary vascular remodeling and hypoxia-induced PH (HPH) in mice. Mechanistically, METTL3-mediated m6A modification of kruppel-like factor 2 (KLF2) plays a crucial role in the EndMT process. KLF2 overexpression increased CD31 and VE-cadherin levels while decreasing SM22, N-cadherin, and EndMT-related transcription factors, thereby mitigating EndMT in PH. Mutations in the m6A site of KLF2 mRNA compromise KLF2 expression, subsequently diminishing its protective effect against EndMT. Furthermore, KLF2 modulates SM22 expression through direct binding to its promoter. CONCLUSIONS: Our findings unveil a novel METTL3/KLF2 pathway critical for protecting hPAECs against EndMT, highlighting a promising avenue for therapeutic investigation in PH.

[Progress in the diagnose and treatment of pulmonary arterial thrombosis in situ].

In situ pulmonary arterial thrombosis (ISPAT) refers to the formation of new blood clots in the pulmonary arterial system in the absence of pre-existing clots in the peripheral venous system. With the emergence and prevalence of COVID-19, ISPAT has become an increasingly important cause of pulmonary arterial thrombosis (PAT) alongside thromboembolism. Several factors such as hypoxia, inflammation, endothelial dysfunction, and hypercoagulable state can lead to ISPAT, which is associated with a number of conditions such as thoracic trauma, partial lung resection, pulmonary infectious disease, pulmonary vasculitis, connective tissue diseases, severe pulmonary hypertension, radiation pneumonitis, and acute chest syndrome in sickle cell disease. It is important to differentiate between pulmonary thromboembolism (PTE) and ISPAT for proper disease management and prognosis. In this review, we summarized the characteristics of ISPAT under different disease conditions, the methods to distinguish ISPAT from PTE, and the best treatment strategies. We hoped that this review could improve clinicians' understanding of this independent disease and provide guidance for the refined treatment of patients with PAT.

[Consensus on the procedure of balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension].

Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as group IV pulmonary hypertension, characterized by thrombotic occlusion of the pulmonary arteries leading to vascular stenosis or obstruction, progressive increase in pulmonary vascular resistance and pulmonary arterial pressure, and eventual right heart failure. Unlike other types of pulmonary hypertension, the prognosis of CTEPH can be significantly improved by surgery, vascular intervention, and/or targeted drug therapy. Pulmonary endarterectomy (PEA) is the preferred treatment of choice for CTEPH. However, PEA is an invasive procedure with high operative risks, and is currently only performed in a few centers in China. Balloon pulmonary angioplasty (BPA) is an emerging interventional technique for CTEPH, serving as an alternative for patients who are ineligible for PEA or with residual pulmonary hypertension after PEA. BPA is gaining traction in China, but its widespread adoption is limited due to its complexity, operator skills, and equipment requirements, a lack of standard operating procedures and technical guidance, which limit the further improvement and development of BPA in China. To address this, a multidisciplinary panel of experts was convened to develop the Consensus on the Procedure of Balloon Pulmonary Angioplasty for the Chronic Thromboembolic Pulmonary Hypertension, which fomulates guidelines on BPA procedural qualification, perioperative management, procedural planning, technical approach, and complication prevention, with the aim of providing recommendations and clinical guidance for BPA treatment in CTEPH and standardizing its clinical application in this setting. Summary of recommendations: Recommendation 1: It is recommended that physicians who specialize in pulmonary vascular diseases take the lead in formulating the diagnostic and treatment plans for CTEPH, using a multidisciplinary approach.Recommendation 2: Training in BPA technique is critical; novice operators should undergo standardized operative training with at least 50 procedures under the guidance of experienced physicians before embarking on independent BPA procedures.Recommendation 3: BPA requires catheterization labs, angiography systems, standard vascular interventional devices and consumables, drugs, and emergency equipment.Recommendation 4: Patient selection for BPA should consider cardiac and pulmonary function, coagulation status, and comorbid conditions to determine indications and contraindications, thereby optimizing the timing of the procedure and improving safety.Recommendation 5: In experienced centers, patients deemed likely to benefit from early BPA, based on clinical and imaging features of CTEPH and without elevated D-dimer levels, could bypass standard 3-month anticoagulation therapy.Recommendation 6: BPA is a complex interventional treatment that requires thorough pre-operative assessment and preparation.Recommendation 7: The use of perioperative anticoagulants in BPA requires a comprehensive risk assessment of intraoperative bleeding by the operator for individualized decision making.Recommendation 8: A variety of venous access routes are available for BPA; unless contraindicated, the right femoral vein is usually preferred because of its procedural convenience and reduced radiation exposure.Recommendation 9: For the different types of vascular lesion in CTEPH, treatment of ring-like stenoses, web-like lesions, and subtotal occlusions should be prioritized before addressing complete occlusions and tortuous lesions, in order to reduce complications and improve procedural safety.Recommendation 10: A targeted, incremental balloon dilatation strategy based on vascular lesions is recommended for BPA.Recommendation 11: Intravascular pulmonary artery imaging technologies, such as OCT and IVUS can assist in accurate vessel sizing and confirmation of wire placement in the true vascular lumen. Pressure wires can be used to objectively assess the efficacy of dilatation during BPA.Recommendation 12: Endpoints for BPA treatment should be individually assessed, taking into account improvements in clinical symptoms, hemodynamics, exercise tolerance, and quality of life.Recommendation 13: Post-BPA routine monitoring of vital signs is essential; anticoagulation therapy should be initiated promptly post-procedure in the absence of complications. In cases of intraoperative hemoptysis, postoperative anticoagulation regimen adjustments should be adjusted according to the bleeding severity.Recommendation 14: If reperfusion pulmonary edema occurs during or after BPA, ensure adequate oxygenation, diuresis, and consider non-invasive positive-pressure ventilation if necessary, while severe cases may require early mechanical ventilation assistance or ECMO.Recommendation 15: In cases of intraoperative hemoptysis, temporary balloon occlusion to stop bleeding is recommended, along with protamine to neutralize heparin. Persistent bleeding may warrant the use of gelatin sponges, coil embolization, or covered stent implantation.Recommendation 16: For contrast imaging during BPA, non-ionic, low or iso-osmolar contrast agents are recommended, with hydration status determined by the patient's clinical condition, cardiac and renal function, and intraoperative contrast volume used.

Analysis of clinical features and prognostic factors in Takayasu arteritis involving pulmonary hypertension: A retrospective study.

BACKGROUND: Multiple takayasu arteritis (TA) is a chronic nonspecific large to medium vasculitis disease that mainly accumulates the aorta and its branches. Pulmonary vascular disease is often seen as stenosis and occlusion, and patients may show no moderate to severe pulmonary hypertension (PH). This study aims to summarize the clinical characteristics and analysis of prognostic factors in patients with PH caused by TA. METHODS: Patients diagnosed with aortitis involving the pulmonary artery by pulmonary arteriography or pulmonary artery and total aortic computed tomography arteriography (CTA). All patients underwent detailed clinical assessment, laboratory data collection, and analysis of imaging data. Patients were followed up and factors affecting the prognosis of the pulmonary arteries were analyzed. RESULTS: Most of the patients' complaints were chest tightness, shortness of breath, decreased activity tolerance, hemoptysis and chest pain. 56.90% of the patients were in at the time of admission. Echocardiographic estimation of pulmonary artery systolic pressure was 90.39 ±â€…22.87 mm Hg. In terms of laboratory tests, 39.66%% of the patients had elevated C-reactive protein and erythrocyte sedimentation rate, and amino-terminal natriuretic peptide precursor on admission. In terms of imaging, all patients had pulmonary artery involvement, which was combined with aortic involvement in 31.03%. Nuclide lung perfusion/ventilation imaging of the patients revealed multiple perfusion defects/absences in the segmental and subsegmental distribution of the lungs. Univariate Cox regression model analysis suggested that patients' WHO functional class at admission, age ≧ 51 years at the time of consultation, and amino-terminal natriuretic peptide precursor ≧ 3500 pg/mL were factors affecting the prognosis. Further multifactorial Cox regression model analysis suggested amino-terminal natriuretic peptide precursor ≧ 3500 pg/mL was an independent predictor of poor prognosis with a hazard ratio (HR) value of 5.248. CONCLUSION: Electrocardiogram and echocardiogram may suggest an increased right heart load; some patients have elevated serum inflammatory indexes. Characteristic imaging manifestations include widening of the main pulmonary artery, multiple pulmonary segmental and subsegmental stenoses.

The efficacy of pulmonary artery catheters in reducing mortality in acute heart failure cardiogenic shock: A systematic review.

BACKGROUND: Cardiogenic shock (CS), a complex and life-threatening medical condition, has an astounding hospital mortality rate spanning from 40 % to 59 %. Frequently, CS requires the use of pulmonary artery catheters (PACs) for management. OBJECTIVE: This literature review aims to investigate the relationship between PAC utilization in CS patients and in-hospital 30-day mortality rates compared to noninvasive vital sign monitoring alone. METHODS: An integrative literature search was conducted from January 1, 2003, until August 1, 2023. The review focused on patients with acute decompensated heart failure CS. It compared PAC and non-PAC hemodynamic monitoring with 30-day mortality outcomes. Five articles met the inclusion criteria and underwent quality assessment using CONSORT, STROBE, and STARD guidelines. RESULTS: Five articles totaled 332,794 patients. Patients with a PAC showed lower 30-day in-hospital mortality rates (22.2 % to 55 %) than patients without a PAC (29.8-78 %). One study, however, indicated that PAC use did not significantly affect mortality rates (p = 0.66). Notably, the lowest mortality rates (25 %) were linked to complete hemodynamic profiling with a PAC. The mortality rates showed greater significance when PAC initiation occurred early, resulting in a further reduction of the mortality rate to 17.3 %. Conversely, mortality rates increased to 27.7 % with delayed PAC initiation, 40 % with incomplete hemodynamic profiling, and 35 % with no PAC use. CONCLUSIONS: PAC utilization reduces in-hospital mortality for the CS patient population, as suggested by the analyzed studies. Further research via randomized controlled trials (RCTs) with standardized treatment protocols and adequate follow-up are required to validate the findings.

TRPC4 aggravates hypoxic pulmonary hypertension by promoting pulmonary endothelial cell apoptosis.

Pulmonary hypertension (PH) is a devastating disease that lacks effective treatment options and is characterized by severe pulmonary vascular remodeling. Pulmonary arterial endothelial cell (PAEC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension. Canonical transient receptor potential (TRPC) channels, a family of Ca2+-permeable channels, play an important role in various diseases. However, the effect and mechanism of TRPCs on PH development have not been fully elucidated. Among the TRPC family members, TRPC4 expression was markedly upregulated in PAECs from hypoxia combined with SU5416 (HySu)-induced PH mice and monocrotaline (MCT)-treated PH rats, as well as in hypoxia-exposed PAECs, suggesting that TRPC4 in PAECs may participate in the occurrence and development of PH. In this study, we aimed to investigate whether TRPC4 in PAECs has an aggravating effect on PH and elucidate the molecular mechanisms. We observed that hypoxia treatment promoted PAEC apoptosis through a caspase-12/endoplasmic reticulum stress (ERS)-dependent pathway. Knockdown of TRPC4 attenuated hypoxia-induced apoptosis and caspase-3/caspase-12 activity in PAECs. Accordingly, adeno-associated virus (AAV) serotype 6-mediated pulmonary endothelial TRPC4 silencing (AAV6-Tie-shRNA-TRPC4) or TRPC4 antagonist suppressed PH progression as evidenced by reduced right ventricular systolic pressure (RVSP), pulmonary vascular remodeling, PAEC apoptosis and reactive oxygen species (ROS) production. Mechanistically, unbiased RNA sequencing (RNA-seq) suggested that TRPC4 deficiency suppressed the expression of the proapoptotic protein sushi domain containing 2 (Susd2) in hypoxia-exposed mouse PAECs. Moreover, TRPC4 activated hypoxia-induced PAEC apoptosis by promoting Susd2 expression. Therefore, inhibiting TRPC4 ameliorated PAEC apoptosis and hypoxic PH in animals by repressing Susd2 signaling, which may serve as a therapeutic target for the management of PH.

Corosolic acid attenuates platelet-derived growth factor signaling in macrophages and smooth muscle cells of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease that is characterized by vascular remodeling of the pulmonary artery. Pulmonary vascular remodeling is primarily caused by the excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), which are facilitated by perivascular inflammatory cells including macrophages. Corosolic acid (CRA) is a natural pentacyclic triterpenoid that exerts anti-inflammatory effects. In the present study, the effects of CRA on the viability of macrophages were examined using monocrotaline (MCT)-induced PAH rats and human monocyte-derived macrophages. Although we previously reported that CRA inhibited signal transducer and activator of transcription 3 (STAT3) signaling and ameliorated pulmonary vascular remodeling in PAH, the inhibitory mechanism remains unclear. Therefore, the underlying mechanisms were investigated using PASMCs from idiopathic PAH (IPAH) patients. In MCT-PAH rats, CRA inhibited the accumulation of macrophages around remodeled pulmonary arteries. CRA reduced the viability of human monocyte-derived macrophages. In IPAH-PASMCs, CRA attenuated cell proliferation and migration facilitated by platelet-derived growth factor (PDGF)-BB released from macrophages and PASMCs. CRA also downregulated the expression of PDGF receptor ß and its signaling pathways, STAT3 and nuclear factor-κB (NF-κB). In addition, CRA attenuated the phosphorylation of PDGF receptor ß and STAT3 following the PDGF-BB simulation. The expression and phosphorylation levels of PDGF receptor ß after the PDGF-BB stimulation were reduced by the small interfering RNA knockdown of NF-κB, but not STAT3, in IPAH-PASMCs. In conclusion, CRA attenuated the PDGF-PDGF receptor ß-STAT3 and PDGF-PDGF receptor ß-NF-κB signaling axis in macrophages and PASMCs, and thus, ameliorated pulmonary vascular remodeling in PAH.

Development and Validation of a Nomogram of Persistent Pulmonary Hypertension in Adult Pretricuspid Shunts After Correction.

BACKGROUND: Pretricuspid shunts have been associated with poorer survival rates in patients with Eisenmenger syndrome compared with postricuspid shunts and complex lesions. However, the risk stratification for persistent pulmonary hypertension (PH) in this population remains uncertain. METHODS AND RESULTS: We retrospectively enrolled 103 patients with pretricuspid shunts with high total pulmonary resistance >4.5 Wood units (estimated pulmonary vascular resistance ≥3 Wood units). During a mean±SD follow-up of 20.95±24.84 months, 32 patients developed postoperative persistent PH after shunt correction. We identified 3 significant predictors of postoperative persistent PH, including mean pulmonary artery pressure after inhaled oxygen ≥40.5 mm Hg (odds ratio [OR], 7.78 [95% CI, 2.02-30.03]; P<0.01), total pulmonary resistance after inhaled oxygen ≥6.5 Wood units (estimated pulmonary vascular resistance ≥5 Wood units; OR, 12.23 [95% CI, 2.12-70.46]; P<0.01), and artery oxygen saturation at rest <95% (OR, 3.34 [95% CI, 1.07-10.44]; P=0.04). We established the prediction model with the C-statistics of 0.85 (95% CI, 0.77-0.93; P<0.01), and the C-statistic was 0.83 (95% CI, 0.80-0.86) after bootstrapping 10 000 times with a good performance of the nomogram calibration curve for predicting persistent PH. CONCLUSIONS: Our study presents a multivariable risk stratification model for persistent PH after shunt correction in adults with pretricuspid shunts. This model, based on 3 hemodynamic predictors after inhaled oxygen, may assist in identifying individuals at higher risk of persistent PH after shunt correction.

Identification of Prostaglandin I2 Synthase Rare Variants in Patients With Williams Syndrome and Severe Peripheral Pulmonary Stenosis.

BACKGROUND: Peripheral pulmonary stenosis (PPS) is a condition characterized by the narrowing of the pulmonary arteries, which impairs blood flow to the lung. The mechanisms underlying PPS pathogenesis remain unclear. Thus, the aim of this study was to investigate the genetic background of patients with severe PPS to elucidate the pathogenesis of this condition. METHODS AND RESULTS: We performed genetic testing and functional analyses on a pediatric patient with PPS and Williams syndrome (WS), followed by genetic testing on 12 patients with WS and mild-to-severe PPS, 50 patients with WS but not PPS, and 21 patients with severe PPS but not WS. Whole-exome sequencing identified a rare PTGIS nonsense variant (p.E314X) in a patient with WS and severe PPS. Prostaglandin I2 synthase (PTGIS) expression was significantly downregulated and cell proliferation and migration rates were significantly increased in cells transfected with the PTGIS p.E314X variant-encoding construct when compared with that in cells transfected with the wild-type PTGIS-encoding construct. p.E314X reduced the tube formation ability in human pulmonary artery endothelial cells and caspase 3/7 activity in both human pulmonary artery endothelial cells and human pulmonary artery smooth muscle cells. Compared with healthy controls, patients with PPS exhibited downregulated pulmonary artery endothelial prostaglandin I2 synthase levels and urinary prostaglandin I metabolite levels. We identified another PTGIS rare splice-site variant (c.1358+2T>C) in another pediatric patient with WS and severe PPS. CONCLUSIONS: In total, 2 rare nonsense/splice-site PTGIS variants were identified in 2 pediatric patients with WS and severe PPS. PTGIS variants may be involved in PPS pathogenesis, and PTGIS represents an effective therapeutic target.

Neutrophil extracellular traps promote proliferation of pulmonary smooth muscle cells mediated by CCDC25 in pulmonary arterial hypertension.

BACKGROUND: Previous studies have indicated that neutrophil extracellular traps (NETs) play a pivotal role in pathogenesis of pulmonary arterial hypertension (PAH). However, the specific mechanism underlying the impact of NETs on pulmonary artery smooth muscle cells (PASMCs) has not been determined. The objective of this study was to elucidate underlying mechanisms through which NETs contribute to progression of PAH. METHODS: Bioinformatics analysis was employed in this study to screen for potential molecules and mechanisms associated with occurrence and development of PAH. These findings were subsequently validated in human samples, coiled-coil domain containing 25 (CCDC25) knockdown PASMCs, as well as monocrotaline-induced PAH rat model. RESULTS: NETs promoted proliferation of PASMCs, thereby facilitating pathogenesis of PAH. This phenomenon was mediated by the activation of transmembrane receptor CCDC25 on PASMCs, which subsequently activated ILK/ß-parvin/RAC1 pathway. Consequently, cytoskeletal remodeling and phenotypic transformation occur in PASMCs. Furthermore, the level of NETs could serve as an indicator of PAH severity and as potential therapeutic target for alleviating PAH. CONCLUSION: This study elucidated the involvement of NETs in pathogenesis of PAH through their influence on the function of PASMCs, thereby highlighting their potential as promising targets for the evaluation and treatment of PAH.