Pulmonary artery stent thrombosis and symptomatic pulmonary hypertension following COVID-19 infection in Alagille patient:A case report

BACKGROUND Alagille syndrome is a multisystem disease that results in various vascular anomalies,commonly involving the cardiac and pulmonary systems.To the best of our knowledge,there is no literature regarding the cardiovascular outcomes of these patients in association with coronavirus disease 2019(COVID-19).CASE SUMMARY A 34-year-old woman with a history of Alagille syndrome who underwent successful atrial septal defect with partial anomalous pulmonary veins and patent ductus arteriosus repair,as well as left pulmonary artery catheterization and stenting in childhood due to pulmonary stenosis.The patient was without any respiratory symptoms and was a dancer prior to contracting COVID-19.Several weeks after her COVID-19 infection,she developed left pulmonary artery stent thrombosis and subsequent symptomatic pulmonary hypertension.A treatment strategy of anticoagulation alongside pharmacological agents for pulmonary hypertension for 3 months followed by balloon pulmonary artery angioplasty to reopen the stenosis was unsuccessful.CONCLUSION In the era of COVID-19,patients with pulmonary vascular malformations and endovascular stents are at an increased risk for chronic thromboembolic disease.Patients may benefit from prophylactic antiplatelet or anticoagulation therapy.Stent thrombosis is a devastating phenomenon and should be treated urgently and aggressively with balloon pulmonary angioplasty,and/or a thrombolytic agent.

Treatment and Clinical Management of Chronic Thromboembolic Pulmonary Hypertension:An Update of Literature Review

Chronic thromboembolic pulmonary hypertension(CTEPH)is a chronic,progressive,debilitating,and life-threa-tening complication of pulmonary embolism(PE).Recent technological advances have permitted various treat-ment options for the treatment of CTEPH,including surgery,angioplasty,and medical treatment,depending on the location and characteristics of lesions.Pulmonary endarterectomy(PEA)is the treatment of choice for CTEPH,as it offers excellent long-term outcomes and a high probability of recovery.Moreover,various medical and interventional therapies are currently being developed for patients with inoperable CTEPH.This review mainly summarizes the current treatment approaches of CTEPH,offering more options for specialist physicians to,thus,better manage chronic thromboembolic syndromes.

Development of pulmonary hypertension remains a major hurdle to corrective surgery in Down syndrome

Down syndrome is the most common chromosomal abnormality encountered in clinical practice with 50%of them having associated congenital heart disease(CHD).Shunt lesions account for around 75%of all CHDs in Down syndrome.Down syndrome patients,especially with large shunts are particularly predisposed to early development of severe pulmonary hypertension(PH)compared with shunt lesions in general population.This necessitates timely surgical correction which remains the only viable option to prevent long term morbidity and mortality.However,despite clear recommendations,there is wide gap between actual practice and fear of underlying PH which often leads to surgical refusals in Down syndrome even when the shunt is reversible.Another peculiarity is that Down syndrome patients can develop PH even after successful correction of shunt.It is not uncommon to come across Down syndrome patients with uncorrected shunts in adulthood with irreversible PH at which stage intracardiac repair is contraindicated and the only option available is a combined heartlung transplant.However,despite the guidelines laid by authorities,the rates of cardiac transplant in adult Down syndrome remain dismal largely attributable to the high prevalence of intellectual disability in them.The index case presents a real-world scenario highlighting the impact of severe PH on treatment strategies and discrimination driven by the fear of worse outcomes in these patients.

Pulmonary hypertension post-liver transplant:A case report

BACKGROUND Liver transplantation(LTx)is vital in patients with end-stage liver disease,with metabolic dysfunction-associated steatotic liver disease being the most common indication.Primary sclerosing cholangitis(PSC)is an important indication.Portopulmonary hypertension,associated with portal hypertension,poses a significant perioperative risk,making pretransplant screening essential.CASE SUMMARY We report the case of a 41-year-old woman with PSC who developed severe pul-monary hypertension years after a successful LTx.She presented with worsening dyspnea on exertion and presyncope.Diagnostic evaluation confirmed severe precapillary pulmonary hypertension without evidence of recurrent portal hy-pertension.Initial management with Sildenafil and Macitentan led to a significant improvement in her symptoms,exercise capacity,and biomarkers.This case highlights the rare development of de novo pulmonary hypertension in a liver transplant recipient without recurrent portal hypertension,possibly linked to autoimmune processes or primary liver disease itself.The patient’s positive re-sponse to the combination therapy underscores the importance of prompt diag-nosis and aggressive management.CONCLUSION In conclusion,pulmonary arterial hypertension post-LTx is a rare but serious complication with a poor prognosis,necessitating further research to better understand its mechanisms and to develop effective strategies for prevention and treatment.

Impact of diabetes mellitus on mortality in pulmonary hypertension:A systematic review and meta-analysis

BACKGROUND Pulmonary hypertension(PH)is a progressive disease characterized by endothelial dysfunction and vascular remodeling and is a leading cause of mortality worldwide.Although it is independently associated with multiple comorbidities,the impact of diabetes mellitus(DM)on mortality in patients with PH remains uncertain.To address this issue,we conducted a systematic review and meta-analysis to investigate the effect of DM on survival in patients with pulmonary hypertension.AIM To investigate the impact of diabetes mellitus on mortality in pulmonary hypertension patients.METHODS We conducted a comprehensive search of four major electronic bibliographic databases like PubMed,Google Scholar,Scopus,and Embase,and identified 106 relevant studies,out of 1561 articles,published since the year 2000 for full-text review.Fourteen retrospective and prospective cohort studies that compared survival between patients with DM and those without DM in the context of PH were deemed eligible for inclusion in our meta-analysis.The study was registered on PROSPERO with the identifier CRD42023390232.RESULTS A total of 116455 patients with PH were included in the meta-analysis,of whom 41228 suffered from DM and 75227 did not.The results of our meta-analysis indicate an elevated mortality rate among PH patients with diabetes mellitus in comparison to those without DM[odds ratio(OR)=1.40,95%CI:1.15–1.70,P=0.0006].The metaregression analysis unveiled a statistically significant negative association between mean age and effect size(coefficient=-0.036,P value=0.018).Conversely,a statistically significant positive association was detected between female proportion and effect size(coefficient=0.000,P value<0.001).CONCLUSION Our meta-analysis,which included approximately 116500 PH patients,revealed that the presence of diabetes mellitus was associated with increased odds of mortality when compared to non-diabetic patients.The metaregression analysis indicates that studies with older participants and lower proportions of females tend to exhibit smaller effect sizes.Clinically,these findings underscore the importance of incorporating diabetes status into the risk stratification of patients with PH with more aggressive monitoring and early intervention to improve prognosis potentially.

Effects of combined aerobic,resistance and inspiratory training in patients with pulmonary hypertension:A systematic review

BACKGROUND Pulmonary hypertension(PH)is a serious progressive disorder of the modern world,characterized by endothelial dysfunction and impaired vasoreactivity.Patients with PH usually present exercise intolerance from the very early stages and reduced exercise capacity.Exercise training has been shown to have beneficial effects in patients with cardiovascular comorbidities.However,data regarding the effects of combined exercise training programs in patients with PH still remains limited.AIM To investigate the effects of combined exercise training programs on exercise capacity and quality of life in patients with PH.METHODS Our search included all available randomized controlled trials(RCTs)regarding combined aerobic,resistance and inspiratory training programs in patients with PH in 4 databases(Pubmed,PEDro,Embase,CINAHL)from 2012 to 2022.Five RCTs were included in the final analysis.Functional capacity,assessed by peak VO_(2)or 6-min walking test(6MWT),as well as quality of life,assessed by the SF-36 questionnaire,were set as the primary outcomes in our study.RESULTS Peak VO_(2)was measured in 4 out of the 5 RCTs while 6MWT was measured in all RCTs.Both indices of functional capacity were significantly increased in patients with PH who underwent combined exercise training compared to the controls in all of the included RCTs(P<0.05).Quality of life was measured in 4 out of 5 RCTs.Although patients improved their quality of life in each group,however,only 2 RCTs demonstrated further improvement in patients performing combined training compared to controls.CONCLUSION By this systematic review,we have demonstrated that combined aerobic,resistance and inspiratory exercise training is safe and has beneficial effects on aerobic capacity and quality of life in patients with PH.Such exercise training regimen may be part of the therapeutic strategy of the syndrome.

Intervention control of aerobic exercise in maintaining quality of life and pulmonary hypertension in hemodialysis patients

BACKGROUND Pulmonary hypertension is a serious complication in the treatment of maintenance hemodialysis patients,which seriously affects the quality of life of patients and threatens their life safety.Prevention,treatment and improvement of pulmonary hypertension are of great significance to improve the quality of life of patients.AIM To investigate the intervention and control of pedal-powered bicycle in maintaining quality of life and pulmonary hypertension in hemodialysis patients.METHODS 73 patients with maintenance hemadialysis combined with pulmonary arterial hypertension at a hemodialysis center in a certain hospital from May 2021 to May 2022 are selected.Patients are divided into two groups,37 cases in the control group(group C)and 36 cases in the intervention group(group I).Patients are divided into two groups,group C is treated with oral administration of betaglandin sodium combined with routine nursing care.Based on group C,group I conducts power cycling exercises.RESULTS After treatment,group I patients had higher muscle strength,36-Item Short Form Health Survey scores,and Kidney Disease Targets Areas scores;The 6-minute walk distance test index level was higher and the Borg score was lower;The group I had lower systolic blood pressure,greater vital capacity,higher positive emotion,lower systolic pulmonary artery pressure index level,higher arterial partial oxygen pressure level,lower pulmonary vascular resistance index level,and higher blood oxygen saturation level[158.91±11.89 vs 152.56±12.81,1795.01±603.18 vs 1907.20±574.15,24.00(22.00,29.00)vs 24.00(22.00,28.00),P<0.001].CONCLUSION Aerobic exercise combined with Western medicine treatment can effectively improve patients'pulmonary hypertension,alleviate their negative emotions,and enable them to achieve a higher level of quality of life.

Prevalence of pulmonary hypertension among children with Down syndrome:A systematic review and meta-analysis

BACKGROUND Pulmonary hypertension(PH)has serious short-and long-term consequences.PH is gaining increasing importance in high risk groups such as Down syndrome(DS)as it influences their overall survival and prognosis.Hence,there is a dire need to collate the prevalence rates of PH in order to undertake definitive measures for early diagnosis and management.AIM To determine the prevalence of PH in children with DS.METHODS The authors individually conducted a search of electronic databases manually(Cochrane library,PubMed,EMBASE,Scopus,Web of Science).Data extraction and quality control were independently performed by two reviewers and a third reviewer resolved any conflicts of opinion.The words used in the literature search were“pulmonary hypertension”and“pulmonary arterial hypertension”;“Down syndrome”and“trisomy 21”and“prevalence”.The data were analyzed by Comprehensive Meta-Analysis Software Version 2.Risk of bias assessment and STROBE checklist were used for quality assessment.RESULTS Of 1578 articles identified,17 were selected for final analysis.The pooled prevalence of PH in these studies was 25.5%.Subgroup analysis was carried out for age,gender,region,year of publication,risk of bias and etiology of PH.CONCLUSION This review highlights the increasing prevalence of PH in children with DS.It is crucial for pediatricians to be aware of this morbid disease and channel their efforts towards earlier diagnosis and successful management.Community-based studies with a larger sample size of children with DS should be carried out to better characterize the epidemiology and underlying etiology of PH in DS.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension:A review

Among five types of pulmonary hypertension,chronic thromboembolic pulmonary hypertension(CTEPH)is the only curable form,but prompt and accurate diagnosis can be challenging.Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH,however these are limited by radiation exposure,subjective qualitative bias,and lack of cardiac functional assessment.This review aims to assess the methodology,diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages,limitations and future research scope.

Pachymic Acid Ameliorates Pulmonary Hypertension by Regulating Nrf2-Keap1-ARE Pathway

Objective:Pulmonary hypertension(PH)is a severe pulmonary vascular disease that eventually leads to right ventricular failure and death.The purpose of this study was to investigate the mechanism by which pachymic acid(PA)pretreatment affects PH and pulmonary vascular remodeling in rats.Methods:PH was induced via hypoxia exposure and administration of PA(5 mg/kg per day)in male Sprague-Dawley rats.Hemodynamic parameters were measured using a right ventricular floating catheter and pulmonary vascular morphometry was measured by hematoxylin-eosin(HE),a-SMA and Masson staining.MTT assays and EdU staining were used to detect cell proliferation,and apoptosis was analyzed by TUNEL staining.Western blotting and immunohistochemistry were used to detect the expression of proteins related to the Nrf2-Keapl-ARE pathway.

Hematological disorders and pulmonary hypertension

Pulmonary hypertension(PH),a serious disorder with a high morbidity and mortality rate,is known to occur in a number of unrelated systemic diseases.Several hematological disorders such as sickle cell disease,thalassemia and myeloproliferative diseases develop PH which worsens the prognosis.Associated oxidant injury and vascular inflammation cause endothelial damage and dysfunction.Pulmonary vascular endothelial damage/dysfunction is an early event in PH resulting in the loss of vascular reactivity,activation of proliferative and antiapoptotic pathways leading to vascular remodeling,elevated pulmonary artery pressure,right ventricular hypertrophy and premature death.Hemolysis observed in hematological disorders leads to free hemoglobin which rapidly scavenges nitric oxide(NO),limiting its bioavailability,and leading to endothelial dysfunction.In addition,hemolysis releases arginase into the circulation which converts L-arginine to ornithine,thus bypassing NO production.Furthermore,treatments for hematological disorders such as immunosuppressive therapy,splenectomy,bone marrow transplantation,and radiation have been shown to contribute to the development of PH.Recent studies have shown deregulated iron homeostasis in patients with cardiopulmonary diseases including pulmonary arterial hypertension(PAH).Several studies have reported low iron levels in patients with idiopathic PAH,and iron deficiency is an important risk factor.This article reviews PH associated with hematological disorders and its mechanism:and iron homeostasis and its relevance to PH.

A meta-analysis of soluble suppression of tumorigenicity 2 （sST2） and clinical outcomes in pulmonary hypertension

Suppression of Tumorigenicity 2 （ST2） is a member of the interleukin （IL）-1 receptor family The ST2 receptor exists in two isoforms - ST2 ligand （ST2L） and soluble ST2 （sST2）.ST2L is a membrane receptor and sST2 is a trun- cated receptor which is soluble in the blood, allowing it to be detected in serum. IL-33 is a member of the IL-1 family of ligand and is the fimctional ligand of ST2L receptor. It binds to the ST2L, thereby mediating its immune function.

The Role of Endogenous Carbon Monoxide in the Hypoxic Vascular Remodeling of Rat Model of Hypoxic Pulmonary Hypertension

We investigated the expression of heme oxygenase 1 (HO 1) gene and production of endogenous carbon monoxide (CO) in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin on the expression of HO 1 gene and pulmonary hypertension. A rat model of hypoxic pulmonary hypertension was recreated by exposure to intermittent normobaric hypoxic environment (10 % O 2). Reverse transcriptase polymerase chain reaction (RT PCR) was performed to determine the level of HO 1 mRNA in the rat lung tissue and double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood. Cardiac catheterization was employed to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathological changes of the intra acinar pulmonary arteries (IAPA). It was found that (1) There was a low level of HO 1 mRNA in normal rat lung tissue, but the level of HO 1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats ( P <0.01). The quantity of COHb was 2-3 times those of control group ( P <0.01 or P <0.05). These were accompanied by the increased of RVSP and the thickened IAPA; (2) Hemin could keep the HO 1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, thereby ameliorating the pathological changes of IAPA. In conclusion, the upregulation of the expression of HO 1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.

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.

Terlipressin improves pulmonary pressures in cirrhotic patients with pulmonary hypertension and variceal bleeding or hepatorenal syndrome

Terlipressin has been shown to improve both pulmonary and systemic hemodynamics in stable cirrhotic patients with pulmonary hypertension,whereas other vasoconstrictors may cause pulmonary pressures to deteriorate We investigated the pulmonary and systemic hemodynamic effects of the first terlipressin dose(2 mg) in 7 cirrhotic patients with PH presenting with variceal bleeding(n=4) or hepatorenal syndrome(n=3).Terlipressin decreased pulmonary vascular resistance(158.8±8.9 vs 186.5±13.9 dynes sec cm-5 ;P=0.003) together with an increase in systemic vascular resistance(2143± 126 vs 1643±126 dynes sec cm-5 ;P<0.001).Terlipressin should be the vasoconstrictor treatment of choice when patients present with variceal bleeding or HRS.

Left atrial diameter and atrial fibrillation,but not elevated NT-proBNP,predict the development of pulmonary hypertension in patients with HFpEF

Background The determinants of pulmonary hypertension(PH)due to heart failure with preserved ejection fraction(HFpEF)have been poorly investigated in patients with cardiovascular diseases(CVD).Methods From July 12017 to March 312019,a total of 149 consecutive HFp EF patients hospitalized with CVD were enrolled in this prospective cross-sectional study.A systolic pulmonary artery pressure(PASP)>35 mm Hg estimated by echocardiography was defined as PH-HFp EF.Logistic regression was performed to establish predictors of PH in HFpEF patients.Results Overall,the mean age of participants was 72±11 years,and 74(49.7%)patients were females.A total of 59(39.6%)patients were diagnosed with PH-HFpEF by echocardiography.The left atrial diameter(LAD)was related to the ratio of the transmitral flow velocities/mitral annulus tissue velocities in early diastole(E/E’)and the left ventricular diameter in systole(LVDs).N-Terminal pro B-type natriuretic peptide(NT-proBNP)was not found to be associated with LAD and impaired diastolic or systolic function of the left ventricle.Multivariable logistic regression showed that atrial fibrillation(AF)increased the risk of PH-HFpEF incidence 3.46-fold with a 95%confidence interval(CI)of 1.44–8.32,P=0.005.Meanwhile,LAD≥45 mm resulted in a 3.43-fold increased risk,95%CI:1.51–7.75,P=0.003.However,the significance levels of NT-proBNP,age and LVEF were underpowered in the regression model.Two variables,AF and LAD≥45 mm,predicted the PH-HFpEF incidence(C-statistic=0.773,95%CI:0.695–0.852,P<0.001).Conclusions Two parameters associated with electrical and anatomical remodelling of the left atrium were related to the incidence of PH in HFpEF patients with CVD.

Circular RNAs in pulmonary hypertension:Emerging biological concepts and potential mechanism

Circular RNAs(circRNAs)are endogenous RNAs with a covalently closed single-stranded transcript.They are a novel class of genomic regulators that are linked to many important development and disease processes and are being pursued as clinical and therapeutic targets.Using the most powerful RNA sequencing and bioinformatics techniques,a large number of circRNAs have been identified and further functional studies have been performed.It is known that circRNAs act as potential biomarkers,sponges for microRNAs(miRNAs)and RNA-binding proteins(RBPs),and regulators of mRNA transcription.They also participate in the translation of peptides or proteins.Many types of circRNAs are dysregulated in plasma or lung tissues,and they may be involved in regulating the proliferation and apoptosis of pulmonary artery endothelial cells(PAECs)and pulmonary artery smooth muscle cells(PASMCs),leading to pulmonary vascular remodeling in pulmonary hypertension(PH).One possible mechanism is that circRNAs can regulate the function of PAECs and PASMCs by acting as miRNA sponge.However,other potential mechanisms of action of circRNAs are still being actively explored in PH.This paper presents a systematic review of the biogenesis,biological characterization,relevant underlying functions,and future perspectives for studies of circRNAs in the pathogenesis of PH.

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.

Role of miR-21-5p/FilGAP axis in estradiol alleviating the progression of monocrotaline-induced pulmonary hypertension

Background:Aberrant expression of microRNAs(miRNAs)has been associated with the pathogenesis of pulmonary hypertension(PH).It is,however,not clear whether miRNAs are involved in estrogen rescue of PH.Methods:Fresh plasma samples were prepared from 12 idiopathic pulmonary arterial hypertension(IPAH)patients and 12 healthy controls undergoing right heart cath-eterization in Shanghai Pulmonary Hospital.From each sample,5μg of total RNA was tagged and hybridized on microRNA microarray chips.Monocrotaline-induced PH(MCT-PH)male rats were treated with 17β-estradiol(E_(2))or vehicle.Subgroups were cotreated with estrogen receptor(ER)antagonist or with antagonist of miRNA.Results:Many circulating miRNAs,including miR-21-5p and miR-574-5p,were mark-edly expressed in patients and of interest in predicting mean pulmonary arterial pres-sure elevation in patients.The expression of miR-21-5p in the lungs was significantly upregulated in MCT-PH rats compared with the controls.However,miR-574-5p showed no difference in the lungs of MCT-PH rats and controls.miR-21-5p was se-lected for further analysis in rats as E_(2) strongly regulated it.E_(2) decreased miR-21-5p expression in the lungs of MCT-PH rats by ERβ.E_(2) reversed miR-21-5p target gene FilGAP downregulation in the lungs of MCT-PH rats.The abnormal expression of RhoA,ROCK2,Rac1 and c-Jun in the lungs of MCT-PH rats was inhibited by E_(2) and miR-21-5p antagonist.Conclusions:miR-21-5p level was remarkably associated with PH severity in patients.Moreover,the miR-21-5p/FilGAP signaling pathway modulated the protective effect of E_(2) on MCT-PH through ERβ.

N-carbamylglutamate restores nitric oxide synthesis and attenuates high altitudeinduced pulmonary hypertension in Holstein heifers ascended to high altitude

Background: High-altitude pulmonary hypertension(HAPH) is a life-threating condition for animals in high altitude,and disturbance of endothelial nitric oxide(NO) synthesis contributes to its pathogenesis. N-carbamylglutamate(NCG), which enhances arginine synthesis, promotes endogenous synthesis of NO. In this study, we determined the effects of NCG on alleviating HAPH in Holstein heifers that ascended to Tibet(Lhasa, 3,658 m).Methods: Exp. 1, 2,000 Holstein heifers were transported from low elevation(1,027 m) to Lhasa. After being exposed to hypoxia for 1 yr, Holstein heifers were assigned to a healthy group(Control, n = 6) with mean pulmonary hypertension(mPAP) < 41 mmHg, and an HAPH affected group(HAPH, n = 6) with mPAP > 49 mmHg.Lung tissues were collected to evaluate histopathological changes and the expression of endothelial nitric oxide synthase(eNOS). Exp. 2, ten healthy heifers and 10 HAPH affected heifers were supplemented with NCG(20 g/d per heifer) for 4 wk. Physiological parameters were determined and blood samples were collected on d-1 and d 28 of the feeding trial.Results: Expression of e NOS in small pulmonary arteriole intima was higher in the healthy than HAPH group(P = 0.006), whereas HAPH group had significantly thicker media and adventitia than healthy group(all P < 0.05). The mRNA of eNOS and protein level of eNOS were higher in the lungs of heifers in the healthy group than in the HAPH group(both P < 0.001), whereas endothelin-1 protein levels were higher in HAPH group than in the healthy group(P = 0.025). NCG supplementation decreased mPAP and ammonia(both P = 0.001), whereas it increased the expression of eNOS, arginine, and plasma NO(all P < 0.05).Conclusions: The expression of eNOS was decreased in Holstein heifers with HAPH. NCG supplementation decreased m PAP through the restoration of eNOS and endogenous NO synthesis.