CircPMS1 promotes proliferation of pulmonary artery smooth muscle cells,pulmonary microvascular endothelial cells,and pericytes under hypoxia

Background:Circular RNAs(circRNAs)have been recognized as significant regulators of pulmonary hypertension(PH);however,the differential expression and function of circRNAs in different vascular cells under hypoxia remain unknown.Here,we identified co-differentially expressed circRNAs and determined their putative roles in the proliferation of pulmonary artery smooth muscle cells(PASMCs),pulmonary microvascular endothelial cells(PMECs),and pericytes(PCs)under hypoxia.Methods:Whole transcriptome sequencing was performed to analyze the differential expression of circRNAs in three different vascular cell types.Bioinformatic analysis was used to predict their putative biological function.Quantitative real-time polymerase chain reaction,Cell Counting Kit-8,and EdU Cell Proliferation assays were carried out to determine the role of circular postmeiotic segregation 1(circPMS1)as well as its potential sponge mechanism in PASMCs,PMECs,and PCs.Results:PASMCs,PMECs,and PCs exhibited 16,99,and 31 differentially expressed circRNAs under hypoxia,respectively.CircPMS1 was upregulated in PASMCs,PMECs,and PCs under hypoxia and enhanced the proliferation of vascular cells.CircPMS1may upregulate DEP domain containing 1(DEPDC1)and RNA polymerase II subunit D expression by targeting microRNA-432-5p(miR-432-5p)in PASMCs,upregulate MAX interactor 1(MXI1)expression by targeting miR-433-3p in PMECs,and upregulate zinc finger AN1-type containing 5(ZFAND5)expression by targeting miR-3613-5p in PCs.Conclusions:Our results suggest that circPMS1 promotes cell proliferation through the miR-432-5p/DEPDC1 or miR-432-5p/POL2D axis in PASMCs,through the miR-433-3p/MXI1 axis in PMECs,and through the miR-3613-5p/ZFAND5 axis in PCs,which provides putative targets for the early diagnosis and treatment of PH.

NR4A1 enhances glycolysis in hypoxia-exposed pulmonary artery smooth muscle cells by upregulating HIF-1αexpression

Background:Pulmonary arterial hypertension(PAH)is a chronic and progressive disease that is strongly associated with dysregulation of glucose metabolism.Alterations in nuclear receptor subfamily 4 group A member 1(NR4A1)activity alter the outcome of PAH.This study aimed to investigate the effects of NR4A1 on glycolysis in PAH and its underlying mechanisms.Methods:This study included twenty healthy volunteers and twenty-three PAH patients,and plasma samples were collected from the participants.To mimic the conditions of PAH in vitro,a hypoxia-induced model of pulmonary artery smooth muscle cell(PASMC)model was established.The proliferation of PASMCs was assessed using CCK8 assays.Results:Levels of NR4A1,hypoxia-inducible factor-1α(HIF-1α),and various glycolysis-related enzymes were measured.In addition,extracellular glucose and lactate production were assessed.The interaction between NR4A1 and HIF-1αwas evaluated by co-immunoprecipitation assays.Levels of NR4A1 and HIF-1αwas increased in PAH patients,and exposure to hypoxia resulted in increased levels of NR4A1 and HIF-1αin PASMCs.NR4A1 interacted with HIF-1α.NR4A1 overexpression enhanced hypoxia-induced expression of HIF-1α,GLUT1,PKM2,HK2,and CD36,decreased glucose levels,increased lactate levels and promoted hypoxic PASMC viability.Conversely,silencing NR4A1 decreased hypoxia-induced expression of HIF-1α,GLUT1,PKM2,HK2,and CD36,promoted glucose production,reduced lactate levels and inhibited hypoxic PASMC viability.Furthermore,overexpression of HIF-1αreversed the regulation of glycolysis caused by NR4A1 knockdown.Conclusion:NR4A1 enhances glycolysis in hypoxia-induced PASMCs by upregulating HIF-1α.Our findings indicate that the management of NR4A1 activity may be a promising strategy for PAH therapy.

“Treat-Repair-Treat”:Management of Left Main Coronary Compression by a Pulmonary Artery Aneurysm in a Patient with Atrial Septal Defect and Significant Pulmonary Hypertension

Left main coronary compression syndrome(LMCS)may complicate pulmonary artery aneurysms(PAA),usually developed in the context of pulmonary arterial hypertension(PAH).We report the case of a 51-year-old female patient with an atrial septal defect(unsuitable for device closure)complicated by a PAA generating a 90%left main stenosis.The significant PAH held us back from immediate surgery.After specific dual PAH-targeted therapy(sildenafil and bosentan),the atrial septal defect could be closed with a unidirectional valved patch;the PAAinduced LMCS was treated by reductive arterioplasty.The postoperative course was uneventful.Follow-up showed clinical improvement,but PAH treatment was still needed.After three months,coronary angiography showed only an insignificant residual left main stenosis,proving that reductive pulmonary arterioplasty was effective in treating LMCS.Any PAA requires further evaluation for LMCS,a dangerous but treatable complication.The“treat-repair-treat”strategy and shunt-closure with a unidirectional valved patch can both improve surgical prospects of LMCS with shunt-related PAH.

Hypoxia Down-regulates Secretion of MMP-2, MMP-9 in Porcine Pulmonary Artery Endothelial and Smooth Muscle Cells and the Role of HIF-1

Summary： Primary cell culture, techniques of gene transfection, gelatin zymography, and Western blot were used to investigate the effect of hypoxia on the secretion of MMP 2 and MMP-9 in pulmonary artery endothelial cells （PAEC） and smooth muscle cells （PASMC）, and the role of HIF-1. Our results showed that （1） after exposure to hypoxia for 24 h, the protein content and activity of MMP-2 in the PAEC medium as well as these of MMP-2 and MMP-9 in PASMC medium （P〈0. 01 ） decreased significantly in contrast to those in normoxic group （P（0.05） ; （2） after transfection of wild type EPO3＇ enhancer, a HIF-1 decoy, the content and activity of MMP 2 and MMP-9 in hypoxic mediums became higher than those in normoxic group （P〈0. 01）, while transfection of mutant EPO3＇-enhancer didn＇t affect the hypoxia-induced down-regulation. It is concluded that hypoxia could inhibit the secretion and activity of MMP 2 and MMP-9 in PAEC and PASMC, which could he mitigated by the transfection of EPO3 ＇-enhancer and that H1F-1 pathway might contribute to hypoxia-induced down regulation of MMP-2 and MMP-9.

Mesenchymal Stem Cells Attenuate Vascular Remodeling in Monocrotaline-induced Pulmonary Hypertension Rats

Intravenous and intratracheal implantation of mesenchymal stem cells (MSCs) may offer ameliorating effects on pulmonary hypertension (PH) induced by monocrotaline (MCT) in rats. The aim of this study was to examine the anti-remodeling effect of intravenous MSCs (VMSCs) and intratracheal MSCs (TMSCs) in rats with PH, and the underlying mechanisms. MSCs were isolated from rat bone marrow and cultured. PH was induced in rats by intraperitoneal injection of MCT. One week after MCT administration, the rats were divided into 3 groups in terms of different treatments: VMSCs group (intravenous injection of MSCs), TMSCs group (intratracheal injection of MSCs), PH group (no treatment given). Those receiving saline instead of MCT served as negative control (control group). Pulmonary arterial structure was pathologically observed, pulmonary arterial dynamics measured, and remodeling-associated cytokines Smad2 and Smad3 detected in the lungs, three weeks after MCT injection. The results showed that PH group versus control group had higher pulmonary arterial pressure (PAP) and wall thickness index (WTI) 21 days after MCT treatment. The expression of phosphorylated (p)-Smad2 and the ratio of p-Smad2/Smad2 were much higher in PH group than in control group. Fluorescence-labeled MSCs were extensively distributed in rats’ lungs in VMSCs and TMSCs groups 3 and 14 days after transplantation, but not found in the media of the pulmonary artery. WTI and PAP were significantly lower in both VMSCs and TMSCs groups than in PH group three weeks after MCT injection. The p-Smad2 expression and the ratio of p-Smad2/Smad2 were obviously reduced in VMSCs and TMSCs groups as compared with those in PH group. In conclusion, both intravenous and intratracheal transplantation of MSCs can attenuate PAP and pulmonary artery remodeling in MCT-induced PH rats, which may be associated with the early suppression of Smad2 phosphorylation via paracrine pathways.

Effects of calcium-activated chloride channels on proliferation of pulmonary artery smooth muscle cells in rats under chronic hypoxic condition

Objective：To investigate the effects of calcium-activated chloride （ClCa） channels on proliferation of pulmonary artery smooth muscle cells（PASMCs） in rats under chronic hypoxic condition. Methods：The cultured PASMCs were placed under normoxic and chronic hypoxic conditions：The cells were observed by light and electron microscope; The cell cycles were observed by flow-cytometry; Immunocytochemistry staining was used to detect the expressions of PCNA, c-fos and c-jun of PASMCs; Cytoplasmic free Ca^2＋ concentration （[Ca^2＋]i） in PASMCs was investigated by fluorescent quantitation using fluorospectrophotometer. Results：The PASMCs were contractile phenotype under normoxic conditions. Observation by transmission electron microscope： In kytoplasm of contractile phenotype cells, myofilament bundles were abundant and the content of cell organs such as Golgi＇s bodies were rare. The PASMCs were synthetic phenotype under chronic hypoxic condition. There were increased free ribosomes, dilated rough endoplasmic reticulums, highly developed Golgi complexes, decreased or disappeared thick filaments and dense body in kytoplasm of synthetic phenotype cells. After NFA and IAA-94, the situations were reversed The number of S ＋G2M PASMCs were significantly increased in chronic hypoxic condition; The NFA and IAA-94 were shown to significantly decrease them from （28.6±1.0）% to （16.0±1.6）% and the number of G0G1 PASMCs significantly increased from （71.4± 1.9）% to （83.9 ± 1.6）% （P〈 0.01）. In chronic hypoxic conditions, the expression of proliferating cell nucleus antigen was significantly increased; The NFA and IAA-94 were shown to significantly decrease it from （81 ± 6）% to （27 ± 7）%（P 〈 0.01）. The expression of c-fos and c-jun were significantly increased in＇chronic hypoxic conditions; The NFA and IAA-94 were shown to significantly decrease them from 0.15 ±0.02, 0.32 ± 0.05 to 0.05 ± 0.01, 0.12 ± 0.05, respectively （P〈 0.01）; Under chronic hypoxic conditions, [Ca^2＋]i was increased; The NFA and IAA-94 decreased it from （281.8±16,5）nmol/L to （117.7 ± 15.4）nmol/L（P 〈 0.01）. Conclusion：Hypoxia initiated the change of PASMCs from contractile to synthetic phenotype and increased proliferation of PASMCs. NFA and IAA-94 depressed cell proliferation by blocking ClCa channels in hypoxic condition. These may play an important role in proliferation of PASMCs under chronic hypoxic conditions.

Correlation between endothelia cells activation and imbalance of cytokines in pulmonary hypertension of congenital heart disease

Objective To explore the correlation between endothelia cells activation and cytokines (ET-1, NO) levels in patients with pulmonary hypertension (PH), and to discuss their roles in the development of PH. Methods Twenty patients with simple ventricular septal defect (VSD) were chosen as controls, and 30 patients with PH were studied. Plasma levels of ET-1 and NO were measured by radioimmunoassay or colorimetric method. Before cardiopulmonary bypass was established, the specimens from right lung were fixed with formaldehyde solution, embedded with paraffin and stained by SP immunohistochemistry. Intercellular adhesion molecule-1 (ICAM-1) expression was measured through the determination of the light density with computer imaging technology. Results Compared with that of the patients with simple VSD, the light density of ICAM-1 and plasma level of ET-1 increased in patients with PH; but plasma level of NO decreased (P<0.05). Positive correlation was observed between ICAM-1 and ET-1/NO (P<0.05). Conclusion Endothelia cells activation and imbalance of ET-1/NO might play an important role in the development of PH.

Involvement of TRPC1 and Cyclin D1 in Human Pulmonary Artery Smooth Muscle Cells Proliferation Induced by Cigarette Smoke Extract

Cigarette smoking contributes to the development of pulmonary artery hypertension(PAH).As the basic pathological change of PAH,pulmonary vascular remodeling is considered to be related to the abnormal proliferation of pulmonary artery smooth muscle cells(PASMCs).However,the molecular mechanism underlying this process remains not exactly clear.The aim of this research was to study the molecular mechanism of PASMCs proliferation induced by smoking.Human PASMCs(HPASMCs)were divided into 6 groups:0%(control group),cigarette smoking extract(CSE)-treated groups at concentrations of 0.5%,1%,2%,5%,10%CSE respectively.HPASMCs proliferation was observed after 24 h.HPASMCs were divided into two groups:0(control group),0.5%CSE group.The mRNA and protein expression levels of transient receptor potential channel 1(TRPC1)and cyclin D1 in HPASMCs after CSE treatment were respectively detected by RT-PCR and Western blotting.The intracellular calcium ion concentration was measured by the calcium probe in each group.In the negative control group and TRPC1-siRNA transfection group,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein were detected.Data were compared with one-way ANOVA(for multiple-group comparison)and independent t-test(for two-group comparison)followed by the least significant difference(LSD)test with the computer software SPSS 17.0.It was found that 0.5%and 1%CSE could promote the proliferation of HPASMCs(P<0.05),and the former was more effective than the latter(P<0.05),while 3%and above CSE had inhibitory effect on HPASMCs(P<0.05).The mRNA and protein expression levels of TRPC1 and cyclin D1 in 0.5%and 1%CSE groups were significantly higher than those in the control group(P<0.05),while those in 3%CSE group were significantly decreased(P<0.05).Moreover,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein in TRPC1-siRNA transfection group were significantly reduced as compared with those in the negative control group(P<0.05).It was concluded that low concentration of CSE can promote the proliferation of HPASMCs,while high concentrations of CSE inhibit HPASMCs proliferation.These findings suggested that CSE induced proliferation of HPASMCs at least in part via TRPC1-mediated cyclin D1 expression.

Pulmonary arterial hypertension confirmed by right heart catheterization following COVID-19 pneumonia: A case report and review of literature

BACKGROUND Pulmonary arterial hypertension(PAH)is a disease of the arterioles resulting in an increased resistance in pulmonary circulation with associated high pressures in the pulmonary arteries,causing irreversible remodeling of the pulmonary arterial walls.Coronavirus disease 2019(COVID-19)has been associated with development of new onset PAH in the literature leading to symptoms of dyspnea,cough and fatigue that persist in spite of resolution of acute COVID-19 infection.However,the majority of these cases of COVID related PAH were diagnosed using echocardiographic data or via right heart catheterization in mechanically ventilated patients.CASE SUMMARY Our case is the first reported case of COVID related PAH diagnosed by right heart catheterization in a non-mechanically ventilated patient.Right heart catheterization has been the gold standard for diagnosis of pulmonary hypertension.Our patient had right heart catheterization four months after her initial COVID-19 infection due to persistent dyspnea.CONCLUSION This revealed new onset PAH that developed following her infection with COVID-19,an emerging sequela of the infection.

Mufangji tang ameliorates pulmonary arterial hypertension through improving vascular remodeling,inhibiting inflammatory response and oxidative stress,and inducing apoptosis

Background:Mufangji tang(MFJT)is composed of Ramulus Cinnamomi,Radix Ginseng,Cocculus orbiculatus(Linn.)DC.,and Gypsum.In clinical settings,MFJT has been effectively employed in addressing a range of respiratory disorders,notably including pulmonary arterial hypertension(PAH).However,the mechanism of action of MFJT on PAH remains unknown.Methods:In this study,a monocrotaline-induced PAH rat model was established and treated with MFJT.The therapeutic effects of MFJT on PAH rat model were evaluated.Network pharmacology was conducted to screen the possible targets for MFJT on PAH,and the molecular docking between the main active components and the core targets was carried out.The key targets identified from network pharmacology were tested.Results:Results showed significant therapeutic effects of MFJT on PAH rat model.Analysis of network pharmacology revealed several potential targets related to apoptosis,inflammation,oxidative stress,and vascular remodeling.Molecular docking showed that the key components were well docked with the core targets.Further experimental validation results that MFJT treatment induced apoptosis(downregulated Bcl-2 levels and upregulated Bax levels in lung tissue),inhibited inflammatory response and oxdative stress(decreased the levels of IL-1β,TNF-α,inducible NOS,and malondialdehyde,and increased the levels of endothelial nitric oxide synthase,nitric oxide,glutathione and superoxide dismutase),reduced the proliferation of pulmonary arterial smooth muscle cells(downregulated ET-1 andβ-catenin levels and ERK1/2 phosphorylation,increased GSK3βlevels).Conclusion:Our study revealed MFJT treatment could alleviate PAH in rats via induction of apoptosis,inhibition of inflammation and oxidative stress,and the prevention of vascular remodeling.

The Effect of Erigeron Breviscapus on Proliferation of Pulmonary Artery Smooth Muscle Cells in Hypoxic Porcines

In order to study the effect of Erigeron Breviscapus (EB) on proliferation of pulmonary artery smooth muscle cells (PASMC) in hypoxic porcines, immunohistochemical and MTT methods were employed to measure the proliferation of PASMC. It was found that the proliferation of PASMC in porcines was obvious, and the expression of proliferating cell nuclear antigen (PCNA) was significantly high within 48 h after exposure to hypoxia. The EB could inhibit the proliferation and the expression of PCNA in PASMC under hypoxia, but it had no effect on the proliferation and expression of PCNA in PASMC under normal condition. The EB could inhibit the proliferation and the expression of PCNA in PASMC induced by phorbol 12-myristate 13-acetate (PMA), an agonist of PKC in normal and hypoxic conditions. It was concluded that the hypoxia could enhance the proliferation and expression of PCNA in PASMC. The EB can inhibit the proliferation and expression of PCNA in PASMC under hypoxia through PKC-signal way. The EB may be used in treating the pulmonary hypertension by inhibiting the proliferation of PASMC and the pulmonary vascular remodeling.

Compression of Left Main Coronary Artery in Patients with Pulmonary Artery Aneurysm and Pulmonary Hypertension

Background: Pulmonary artery aneurysm (PAA) is an unusual finding and its association with left main coronary (LMCA) compression is even more infrequent. Cardiac CT evaluates of presence and size of PAA and the degree of LMCA compression. The aim of this study is to describe two cases of adults with compression of LMCA with PAA associated with PDA and pulmonary hypertension. Case presentation: The first case is a 27-year-old man with PAA (78 mm diameter) and LMCA compression of 70% between the aortic sinus and the PAA. He presented angina as a manifestation of the LMCA compression. During follow-up the patient died. The second case is a 28-year-old man with PAA (110 mm diameter) that compresses LMCA in 55%, he rejected surgical treatment, but he is in close follow-up with medical treatment. Conclusion: Cardiac computed tomography played an important role both in the diagnosis and identification of high-risk PAA patients.

Early Results of Mitral Valve Replacement in Severe Pulmonary Artery Hypertension—An Institutional Prospective Study

Introduction: In patients undergoing surgery for mitral valve replacement (MVR) for valvular heart disease, pulmonary artery hypertension (PAH) has been considered a major risk factor. In this prospective study, we have studied the early hemodynamic changes and post-operative outcomes of MVR among patients with severe PAH. Methods: 68 consecutive patients who underwent mitral valve replacement for severe rheumatic mitral valve disease with severe PAH (pulmonary artery pressure (PAP) > 50 mmHg) were studied prospectively for immediate postoperative hemodynamics and outcomes. The mean age of the patients was 32.1 years. 32 (47.05%) patients had mitral stenosis, 13 (19.11%) had mitral regurgitation and 23 (33.82%) had mixed lesions. Patients were divided into two groups based on preoperative pulmonary artery pressures. In 56 patients (82.35%, group I) PAP was sub-systemic or systemic, with a mean of 58.4 mmHg. Twelve patients (17.65%, group II) had supra-systemic PAP with a mean of 82.4 mmHg. Results: After mitral valve replacement, the PAP and pulmonary vascular resistance (PVR) decreased significantly in group I to near normal levels. In group II also the PAP and PVR decreased significantly but significant residual PAH remained. Operative mortality was 3.5% in group I and 16.6% in group II. Conclusions: MVR is safe and effective at the presence of severe PAH as long as the PAP is below or equal to systemic pressures. With suprasystemic PAP, MVR carries a high risk of mortality and the patient continues to have severe PAH in the postoperative period.

Chronic thromboembolic pulmonary hypertension(CTEPH):outcomes of surgical effect in patients with unilateral main pulmonary artery occlusion

Objective To summarize the clinical characteristics and the effect of pulmonary endarterectomy(PEA)in CTEPH patients with unilateral main pulmonary artery occlusion.Methods Of 160 CTEPH patients operated between January2004 and March 2018 at our center,13(8.1%)had complete main pulmonary artery occlusion.Patients were included if the ventilation/perfusion(V/Q)scan revealed nonperfusion of an entire lung and the pathological examination showed chronic thromboembolic.

Role of Na^+/H^+ antiporter in pulmonary artery smooth muscle of hypoxic pulmonary hypertension in the rat

Objective: To investigate the role of Na+ /H+ antiporter in the hypoxic pumonary hypertension ofrats. Methods: Thirty Wistar rats were randomly divided into 3 groups with 10 in each group: controlgroup, 3--week hypoxia group and 8--week hypoxia group. After the isolation of pulmonary artery smoothmuscles, pHi was determined by fluorescence measurement of the pH--sensitive dye BCECF and theexpression of NHE--1 mRNA was detected with reverse transcription--polymerase chain reaction. Results: ThepHi and expression of NHE-1 mRNA of pulmonary artery smooth muscle cell in the hypoxia groups weresignificantly increased than those in the normal group (P < 0. 01 ). There was no remarkable differencebetween the hypoxia groups. Conclusion: With the function of regulation pHi., NHE--1 may play an importantrole in the pulmonary vascular remodeling of pulmonary hypertension. The result provides a new therapeuticmethod with NHE--1 inhibitors and/or gene therapy for the hypoxic pulmonary hypertension.

Pulmonary Hypertension Crisis in Patient with Tetralogy of Fallot and Mixed Total Anomalous Pulmonary Vein Connection after the Primary Correction:A Rare Case Report

Tetralogy of Fallot(TOF)with total anomalous pulmonary vein connections(TAPVC)is a rare type of complex congenital heart disease among all TOF cases.Co-presentation of major aortopulmonary collateral arteries(MAPCAs)compensates for the lack of central pulmonary bloodflow and decreases the severity of right-to-left shunting in TOF.We present a case of a 2-year-old child with complex diagnoses of TOF,TAPVC,a large secun-dum atrial septal defect(ASD),and intraoperatively identified MAPCAs.She underwent surgery to repair the TAPVC,valve-sparing reconstruction of the right ventricular outflow tract,interventricular defect closure,and the creation of patent foramen ovale(PFO).After the operation,hemodynamic instability happened along with sudden blood pressure drop,desaturation,and increased central venous pressure,which subsided after adminis-tering inhalational nitric oxide(NO).A postoperative pulmonary hypertension crisis was suggested when the patient experienced recurrent symptoms after the termination of NO.Echocardiographicfindings of a D-shaped left ventricle(LV),right-to-left PFO shunt and high tricuspid valve gradientfirmly established the diagnosis.It was subsequently managed with continuous NO inhalation and sildenafil,which rendered a satisfactory outcome.Repaired TOF and TAPVC could be at particular risk of developing pulmonary hypertension crisis,especially in the presence of MAPCAs due to possible remodeling of the pulmonary vasculature.Furthermore,a relatively non-compliant LV function and small left atrial size may exacerbate the risk of developing postcapillary pulmonary hypertension after TAPVC repair.A successful postoperative outcome calls for a meticulous preoperative analysis of the anatomical lesions,as well as careful monitoring.

Inhibitory Effect of PPARδAgonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway

Objective This study aimed to investigate the effects of the peroxisome proliferator-activated receptorδ(PPARδ)agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells(PASMCs)induced by hypoxia,in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling.Methods PASMCs were incubated with different concentrations of GW501516(10,30,100 nmol/L)under the hypoxic condition.The proliferation was determined by a CCK-8 assay.The cell cycle progression was analyzed by flow cytometry.The expression of PPARδ,S phase kinase-associated protein 2(Skp2),and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting.Then PASMCs were treated with 100 nmol/L GW501516,100 nmol/L mammalian target of rapamycin(mTOR)inhibitor rapamycin and/or 2µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs.Results The presented data demonstrated that hypoxia reduced the expression of PPARδin an oxygen concentration-and time-dependent manner,and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle.In accordance with these findings,GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs.Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation,arresting the cell cycle,regulating the expression of Skp2 and p27,and inactivating mTOR in hypoxia-exposed PASMCs.Moreover,MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs.Conclusion GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

Bosentan Is Associated with a Reduction in Right Ventricular Systolic Pressure N-Terminal Pro-Hormone B-Type Natriuretic Peptide Levels in Young Patients with Pulmonary Hypertension

Pulmonary hypertension is a rare and potentially fatal disease in children if left untreated. Emerging therapies, including Bosentan, a dual endothelin receptor antagonist, have shown significant benefits in the adult pulmonary hypertension population;however, few studies have assessed the efficacy and safety of endothelin receptor antagonists in infants and young children. Our study was a single-center retrospective analysis of patients less than two years of age with a confirmed diagnosis of pulmonary hypertension and initiated on Bosentan therapy between 2017 and 2020. Twelve cases met eligibility criteria. Demographic data, laboratory data, echocardiographic, and cardiac catheterization data were analyzed. With treatment, there was a statistically significant decrease in mean right ventricular systolic pressure estimated by the tricuspid regurgitation jet (79 ± 23 mmHg reduced to 52 ± 25 mmHg;p < 0.001) N-terminal pro-hormone B-type natriuretic peptide levels (21,071 reduced to 2,037;p < 0.001). Additionally, improvement and eventual normalization of right ventricular function and septal geometry was seen within the first four months of therapy. Patients who underwent cardiac catheterization after therapy initiation (n = 4) demonstrated hemodynamic improvements;however, only the decrease in diastolic pulmonary artery pressure was statistically significant (p = 0.018). No significant differences in hemoglobin, platelet count, or liver function tests were observed between groups. In conclusion, these data suggest that Bosentan may be an effective and relatively safe treatment option for children less than two years of age with pulmonary hypertension. Further long-term randomized control studies are necessary to validate the potential clinical benefit of utilizing this drug therapy in young children.

Plasma endothelin-1 and nitric oxide correlate with ligustrazine alleviation of pulmonary artery hypertension in patients of chronic cor pulmonale from high altitude plateau during acute exacerbation

Objective To explore the mechanisms involved in the ligustrazine alleviation of the pulmonary artery hypertension(PAH) in patients of chronic obstructive pulmonary disease(COPD) associated with chronic cor pulmonale(CCP) during exacerbation.Methods Seventy patients of COPD and CCP with acute exacerbation were randomly and equally divided into control group and treatment group.The control group received standard treatment with antibiotics,antiasthmatic and expectorant medications,and oxygenation;and the ligustrazine treatment group received ligustrazine treatment(80 mg/d;i.v.;for 2 weeks) in addition to the standard treatment.Before and at the end of 2 week treatment,the clinic responses of the two regimens were evaluated,plasma levels of endothelin-1(ET-1) and nitric oxide(NO) were determined;arterial oxygen partial pressure(PaO_2),mean pulmonary arterial pressure(mPAP),outflow tract of right ventricle(RVOT),and internal diameter of right ventricle(RV) were measured.Results Good clinic benefits were achieved in both the standard and ligustrazine regimens,plasma level of ET-1,values of mPAP,RV and RVOT decreased significantly,plasma level of NO and PaO_2 values decreased(all P<0.01 vs pretreatment to all parameters).Compared with the control group,ligustrazine greatly enhanced the clinic efficacy from 77.1%to 97.1%(P<0.05),and also resulted in more significant changes of all these parameters(P<0.01 vs control group for all parameters).For both groups,the levels of plasma ET-1 were positively correlated with values of mPAP,RVOT,and RV(r = 0.710,0.853,and 0.766,respectively,all P = 0.000),and negatively correlated with plasma NO and PaO_2(r =- 0.823,and- 0.752,respectively,all P = 0.000).Conclusion Ligustrazine is effective in treating pulmonary artery hypertension during acute exacerbation of COPD and CCP in patients from the plateau area.The observed changes in the plasma levels of NO and ET-1 in response to ligustrazine treatment suggest that ligustrazine may act through the selective effect on pulmonary blood vessels to enhance the synthesis and release of NO and suppress those of ET-1 from lung vascular endothelial cells,thus reducing pulmonary artery pressure and decreasing pulmonary arterial hypertension.

THE ROLES OF bcl-2 GENE FAMILY IN THE PULMONARY ARTERY REMODELING OF HYPOXIA PULMONARY HYPERTENSION IN RATS

Objective. To investigate the roles of apoptosis in the pulmonary artery remodeling of pulmonary hypertension secondary to hypoxia and illustrate the relative genes expression. Methods. Thirty rats were divided into hypoxia group（ 10％ O2, 8h/d） and normal control group. On the 15th day of hypoxia, pulmonary artery pressure and right ventricular hypertrophy index were measured and pulmonary artery vessels were studied by light microscope. Then terminal deoxynucleotidyl transferase- mediated dUTP nick- end labeling（ TUNEL） technique was used to detect nucleosomal DNA fragmentation of apoptotic cells. In situ hybridization and RT- PCR were used to detect the expression level of bcl- 2 and bax. Results. The pulmonary artery pressure and right ventricular hypertrophy index of hypoxia group were increased significantly, the pulmonary artery wall of hypoxic group become incrassate than control group. Apoptotic cells can be found in lung with hypoxia or without hypoxia. Compared with control group, apoptotic index of hypoxic group decreased significantly. Through the methods of in situ hybridization and RT- PCR, we found the expression of bcl- 2 increased whereas bax decreased significantly in the hypoxic group. Conclusion. The alternation in bcl- 2 and bax expression induced by hypoxia play an important role in the pulmonary artery remodeling which is the main pathologic change of pulmonary hypertension secondary to hypoxia.