间歇性低压低氧预适应延缓大鼠低氧性肺动脉高压发展并改善肺动脉舒张

目的 观察间歇性低压低氧预适应对大鼠低氧性肺动脉高压（HPH）及肺动脉舒张功能的影响。方法 将24只雄性SD大鼠随机分为:对照组、HPH组、间歇性低压低氧预适应组,每组8只。对照组动物常规饲养10周;HPH组动物先在同一室内常规饲养6周,然后按低压低氧法建立HPH模型（给予持续低压低氧4周）;间歇性低压低氧预适应组动物先给予预适应实验:HPH 1周,再放置同一室内常规饲养1周,如此重复循环3个周期共6周,然后按低压低氧法建立HPH模型（方法同HPH组）。分组模型建立后,用右心导管法测定肺动脉平均压（mPAP）、右心室平均压（mRVP）;称重测量右心室/（左心室+室间隔）〔RV/(LV+S)〕、右心室/体质量（RV/BW）;HE染色高倍镜下观察肺小动脉显微结构改变;取大鼠左、右肺动脉干制备血管环,行离体血管灌流实验,观察不同浓度乙酰胆碱和硝普钠的舒张血管作用。结果 与对照组比,HPH组大鼠的mPAP、mRVP、RV/(LV+S)、RV/BW均显著增高（P<0.01）;病理切片显示低氧后大鼠肺动脉平滑肌和弹力纤维层增生,血管壁增厚,管腔狭窄、变形;且低氧后大鼠肺动脉血管环对乙酰胆碱的舒张作用显著降低（P<0.01）。与HPH组比,经间歇性低压低氧预适应处理的大鼠mPAP、mRVP、RV/(LV+S)、RV/BW均显著降低（P<0.05）;病理切片显示肺动脉平滑肌和弹力纤维层增生及血管壁增厚有所缓解;且肺动脉血管环对乙酰胆碱的舒张作用显著增强（P<0.05）。结论 间歇性低压低氧预适应可增强大鼠肺动脉对低压低氧环境的耐受能力,延缓肺动脉高压和右心重构的发展,并改善肺动脉内皮功能。     

安立生坦与波生坦对低氧性肺动脉高压大鼠右心室重构影响的比较研究

目的:比较安立生坦(ambrisentan)与波生坦(bosentan)对低氧性肺动脉高压大鼠(HPH)右心室重构的影响。方法:40只SD大鼠随机分成5组:正常对照组、模型组、安立生坦组、波生坦组、安慰剂组,每组8只。正常对照组于自然环境中饲养4周,其他组置于低压低氧舱中(8 h/d)饲养4周。从低氧开始第3周起,安立生坦组、波生坦组和安慰剂组大鼠每天进舱前依次分别给予安立生坦(5 mg/kg)、波生坦(125 mg/kg)及生理盐水(2 ml)灌胃,共两周。实验结束后,测定平均肺动脉压(mPAP)和右心室收缩压(RVSP);计算右心室肥厚指数[RV/(LV+S)]及右心室质量/体质量(RW/BW)。右心室心肌以HE染色后,观察其形态学变化,以Masson染色后观察心肌胶原纤维容积分数(CVF)的变化。结果:与模型组和安慰剂组相比,安立生坦组和波生坦组的mPAP、RVSP、RV/(LV+S)、RW/BW、CVF值明显降低(P<0.05),安立生坦组和波生坦组相比,上述指标的差异无明显的统计学意义。HE染色切片显示,模型组和安慰剂组大鼠心肌细胞肥大,安立生坦组和波生坦组可基本恢复至正常组状态。结论:安立生坦与波生坦能显著降低HPH大鼠的肺动脉压力,抑制右心室肥厚及纤维化。安立生坦与波生坦相比,对HPH大鼠右心室重构的影响无明显差别。     

低氧诱导大鼠肺动脉中5-HT_(1B)受体的过度表达

目的:观察低氧对大鼠肺动脉中5-羟色胺1B(5-HT1B)受体表达的影响,初步探讨了5-HT1B受体在低氧性肺动脉高压形成中的变化。方法:40只健康雄性SD大鼠随机分为正常组、低氧3周组、低氧4周组和低氧6周组,每组10只。除正常组外,其余3组大鼠分别在低氧环境中饲养3周、4周和6周。测定各组大鼠的平均肺动脉压力(mPAP)、右心室收缩压(RVSP)和右心室肥厚度。应用免疫组化染色法检测大鼠肺动脉上5-HT1B的分布和表达;用Western blot法测定大鼠肺组织中5-HT1B受体蛋白的含量。结果:与正常组相比,低氧3周组大鼠的mPAP、RVSP和右心室肥厚度均显著升高(均P0.05),并且随着低氧时间的延长而持续升高(均P0.05)。免疫组化染色的结果显示,5-HT1B受体主要分布在正常大鼠肺动脉的内膜层,平滑肌肌层中仅有少量表达;与正常组相比,低氧3周组大鼠肺动脉平滑肌肌层中5-HT1B受体的表达显著增多(P0.05);随着低氧时间的延长,表达持续增多。Western blot的结果表明,大鼠肺组织中5-HT1B受体蛋白含量的变化与免疫组化染色法检测的结果相一致。结论:低氧可以诱导大鼠肺动脉中5-HT1B受体的过度表达,这可能是5-羟色胺系统参与低氧性肺动脉高压形成的机制之一。     

血管内皮生长因子和内皮素在低氧性肺血管重建中的作用

目的探讨血管内皮生长因子(VEGF)和内皮素(ET)-1在低氧性肺动脉高压(HPH)及其肺血管重建中的作用,并观察钾通道开放剂(pinacidil)对HPH的防治作用及对VEGF和ET-1的影响.方法Wister大鼠46只,随机分为3组,对照组15只,低氧组16只,治疗组15只.缺氧组和治疗组大鼠缺氧[氧浓度为(10.0±0.5)%]4周,每天缺氧8h,其中治疗组大鼠于每天缺氧前腹腔注射pinacidil3mg/kg.缺氧4周后测定各组大鼠血清VEGF和血浆ET-1水平、平均肺动脉压(mPAP)、右心室(RV)/[左心室(LV)+室间隔(S)]比值及肺小动脉病理及其形态计量学.结果(1)缺氧组大鼠血清VEGF[(118.73±55.40)ng/L]和血浆ET-1[(221.2±56.2)ng/L]水平明显高于对照组(P＜0.01);缺氧组较对照组mPAP升高,RV/(LV+S)比值增高,肺小动脉血管壁显著增厚,管腔明显狭窄.(2)治疗组大鼠血清VEGF[(78.20±16.45)ng/L]和血浆ET-1[(181.6±30.5)ng/L]水平明显低于缺氧组(P＜0.01);治疗组较缺氧组mPAP下降(P＜0.01),肺小动脉血管壁增厚、管腔狭窄等明显减轻,但治疗组上述各指标仍未完全恢复到对照组水平.结论VEGF和ET-1在HPH及其肺血管重建中发挥重要作用,钾通道开放剂对HPH及其肺血管重建具有一定的逆转作用.     

脂肪因子CTRP9对低氧性肺动脉高压大鼠肺血管的舒张作用及其机制

目的 观察脂肪因子C1q/肿瘤坏死因子相关蛋白9(CTRP9)对于低氧性肺动脉高压(HPH)大鼠离体肺动脉的舒张作用,并探讨其可能的分子机制。方法 将24只雄性SD大鼠随机分为对照组、HPH 2周组和HPH 4周组,每组8只。对照组动物在正常环境中饲养,低氧组动物按低压低氧法建立HPH模型。模型建立后,用右心导管法测定肺动脉平均压(m PAP)、右心室平均压(mRVP),称质量测量右心室/(左心室+室间隔)〔RV/(LV+S)〕、右心室/体质量(RV/BW);ELISA法检测血清NO和CTRP9水平;HE染色高倍镜下观察肺小动脉显微结构改变。取大鼠左、右肺动脉干制备血管环,行离体灌流实验,观察不同浓度CTRP9的舒张血管作用;收集作用于血管环的灌流液,检测NO产物。收集剩余的肺动脉血管组织,分组后用不同浓度CTRP9孵育,部分组别孵育前加入Compound C或L-NAME,然后行Western blot检测p AMPK/AMPK、p Akt/Akt、pe NOS/e NOS等信号蛋白分子。结果 与对照组比,HPH组大鼠的m PAP、mRVP、RV/(LV+S)、RV/BW均显著增高(P<0.01),且血清NO、CTRP9水平下降(P<0.05,P<0.01)。病理切片显示HPH组大鼠肺动脉平滑肌和弹力纤维层增生,血管壁增厚,管腔狭窄、变形。选取对乙酰胆碱和硝普钠有良好舒张反应的血管环,加入CTRP9后血管环明显舒张,预先加入Compound C或L-NAME组,CTRP9舒血管作用被显著抑制;血管环组织AMPK、Akt和e NOS磷酸化水平、灌流液NO产物增加(P<0.05,P<0.01)。结论 HPH时血管内皮功能受损,CTRP9有明显的舒张血管作用,其机制可能与增加AMPK/Akt/e NOS磷酸化和NO释放有关。     

Right ventricular and pulmonary vascular function indices for risk stratification of patients with pulmonary regurgitation

Background: We hypothesized that echocardiographic indices of right ventricular to pulmonary artery (RV‐PA) coupling were comparable to cardiac magnetic resonance imaging (CMRI)‐derived RV volumetric indices in predicting disease severity in chronic pulmonary regurgitation (PR).
Methods: Patients with ≥ moderate PR (2003‐2015) with and without prior CMRI scans were enrolled into the study cohort and validation cohort, respectively. Endpoint was to determine the association between noninvasive RV‐PA coupling in‐ dices (tricuspid annular plane systolic excursion/right ventricular systolic pressure [TAPSE/RVSP] and fractional area change [FAC]/RVSP ratio) and markers of disease severity, and compared this association to that of CMRI‐derived RV volumetric indi‐ ces and markers of disease severity (peak oxygen consumption [VO2], NT‐proBNP and atrial and/or ventricular arrhythmias).
Results: Of the 256 patients in the study cohort (age 33 ± 6 years), 187 (73%) had tetralogy of Fallot (TOF) while 69 (27%) had valvular pulmonic stenosis (VPS). TAPSE/ RVSP (r = 0.73, P < .001) and FAC/RVSP (r = 0.78, P < .001) correlated with peak VO2. Among the CMRI‐derived RV volumetric indices analyzed, only right ventricular end‐ systolic volume index correlated with peak VO2 (r = −0.54, P < .001) and NT‐proBNP (r = 0.51, P < .001). These RV‐PA coupling indices were tested in the validation cohort of 218 patients (age 37 ± 9 years). Similar to the study cohort, TAPSE/RVSP (r = 0.59, P < .001) and FAC/RVSP (r = 0.70, P < .001) correlated with peak VO2. TAPSE/RVSP (but not FAC/RVSP) was also associated with arrhythmia occurrence in both the study cohort and validation cohorts.
Conclusion: Noninvasive RV‐PA coupling may provide complementary prognostic data in the management of chronic PR. Further studies are required to explore this clinical tool.     

吡那地尔防治大鼠低氧性肺动脉高压肺血管重建的实验研究

目的研究钾通道开放剂吡那地尔对低氧性肺动脉高压（ＨＰＨ）及其肺血管重建的影响。方法Ｗｉｓｔｅｒ大鼠４６只,随机分为３组：对照组１５只;低氧组１６只;治疗组（低氧＋吡那地尔）１５只。低氧组及治疗组建立低氧性肺动脉高压动物模型,治疗组于每天缺氧前腹腔注射吡那地尔３ｍｇ／ｋｇ。 ４周后测定各组平均肺动脉压（ｍＰＡＰ）、右心室（ＲＶ）／左心室＋室间隔（ＬＶ＋ Ｓ）比值和肺小动脉病理及其形态计量学。结果（１）低氧组ｍＰＡＰ、ＲＶ／（ＬＶ＋Ｓ）分别为（２８．４ ± ２．８）ｍｍＨｇ和（０．３０±０．０３）,明显高于对照组（１６．２±１．８）ｍｍ Ｈｇ和（０．２２±０．０３）（Ｐ＜０．０１）,管壁厚度与血管外径比值（ＭＴ％）、管壁面积与血管总面积比值（ＭＡ％）分别为（２５．７±２．６）％和（７５．３±５．６）％,亦明显高于对照组（１８．５±２．９）％和（５９．９±６．６）％（Ｐ＜０．０１）,管腔面积与血管总面积比值（ＶＡ％）为（２４．３±５．６）％,明显低于对照组（４０．７±８．１）％（Ｐ＜０．０１）。提示慢性缺氧导致大鼠发生明显肺动脉高压及右心室肥厚和肺小动脉管壁增厚、管腔狭窄等肺血管重建等改变。（２）治疗组ｍＰＡＰ、ＲＶ／     

脂联素改善间歇性低氧性肺动脉高压大鼠离体肺动脉舒张功能及其机制

目的 研究重组人球状脂联素（gAd）对低氧性肺动脉高压（HPH）大鼠离体肺动脉舒张功能的影响并研究其作用机制。方法 将24只雄性SD大鼠随机分为正常对照组、HPH 2周组（HPH2W）、HPH 4周组（HPH4W）,每组8只。正常对照组动物在正常环境中饲养,低氧组大鼠以间歇性低压低氧法建立HPH模型。低氧组模型建立后,以右心导管法测定平均肺动脉压（mPAP)、平均右心室压(mRVP),称重测量右心室/左心室+室间隔（RV/LV+S）、右心室/体质量（RV/BW）;ELISA检测试剂盒检测血清gAd及NO浓度。右肺下叶肺组织经HE染色后观察肺小动脉血管显微结构的改变。取大鼠左、右肺动脉干制备血管环,行离体灌流实验,观察不同浓度的乙酰胆碱及硝普钠诱导的血管舒张作用。取HPH4W组动物肺外肺动脉干,分组进行孵育（HPH4W组:Krebs液孵育;HPH4W+gAd组:gAd 2 μg/ml孵育;HPH4W+gAd+L-NAME组:gAd 2 μg/ml+L-NAME 0.5 mmol/L孵育）,孵育后观察不同浓度的乙酰胆碱及硝普钠诱导的血管舒张作用,然后收集作用于血管环的灌流液,检测NO产物。取HPH4W组大鼠肺动脉血管按上述分组进行孵育,然后行Western blot检测AMPK、Akt、eNOS等信号蛋白分子的表达及磷酸化水平。结果 与正常对照组相比,HPH组大鼠的mPAP、mRVP、RV/LV+S、RV/BW均显著增高（P<0.05）;血清gAd、NO水平下降（P<0.05）;光镜下肺动脉平滑肌及弹力纤维层增生,管壁增厚,管腔狭窄。与正常对照组比较,HPH组大鼠肺动脉对乙酰胆碱诱导的血管舒张作用明显减弱(P<0.05),正常对照组最大舒张率69.94%,HPH2W组最大舒张率48.79%,HPH4W组最大舒张率仅42.09%。经gAd体外孵育后,血管环内皮依赖的舒张作用明显增强,HPH4W组最大舒张率可达到46.35%,加入L-NAME组的血管环舒张作用被显著阻断。各组大鼠对硝普钠诱导的血管舒张均有良好反应,无统计学意义。经gAd孵育后的血管环组织AMPK、Akt、eNOS磷酸化水平、灌流液NO产物均增加（P<0.05）,L-NAME可阻断gAd增强eNOS磷酸化和NO水平的作用。结论 gAd对间歇性低氧性肺动脉高压大鼠的肺动脉内皮依赖性的血管舒张功能具有确切的直接保护作用。AMPK/Akt/eNOS/NO信号通路可能是gAd发挥肺动脉保护作用的分子机制。     

Low-molecular-weight heparin inhibits hypoxic pulmonary hypertension and vascular remodeling in guinea pigs

RATIONALE: We have shown previously that antiproliferative unfractionated heparins block hypoxia-induced pulmonary arterial hypertension (PAH) and vascular remodeling, and hypothesized that low-molecular-weight heparins (LMWHs) would too. OBJECTIVES: To determine the potential role and mechanisms of dalteparin and enoxaparin (two LMWHs) in inhibiting hypoxic PAH and vascular remodeling. METHODS: Male Hartley guinea pigs were exposed for 10 days to normobaric 10% oxygen with dalteparin (5 mg/kg), enoxaparin (5 mg/kg), or with an equivalent volume of normal saline solution. Normoxic control animals (n = 5) received room air for 10 days. Bovine pulmonary artery smooth-muscle cells (PASMCs) were grown in 10% fetal bovine serum without heparin, with dalteparin (1 microg/mL) or with enoxaparin (1 microg/mL). MEASUREMENTS: Pulmonary arterial pressure (PAP), cardiac index, right ventricular heart weight divided by left ventricular plus septum weight (RV/LV+S), hematocrit, percentage of wall thickness of intraacinar vessels (%WT-IA), percentage of wall thickness of terminal bronchiole vessels (%WT-TA), and the percentage of thick-walled vessels (%Thick) were determined. In PASMCs, expression of p27 and cell growth were compared because in mice whole heparin depends on p27 for its antiproliferative action. MAIN RESULTS: In hypoxic animals, hematocrit, PAP, total pulmonary vascular resistance index, RV/LV+S, %WT-IA, %WT-TA, and %Thick all rose significantly vs normoxic control animals (p < 0.05); cardiac index was unchanged. Dalteparin but not enoxaparin significantly reduced PAP, total pulmonary vascular resistance index, and RV/LV + S (p < 0.05 vs hypoxia alone); inhibited PASMC growth; and upregulated p27 expression. Enoxaparin moderately reduced vascular remodeling, which did not translate into less pulmonary hypertension. CONCLUSIONS: Not all LMWHs are the same. Dalteparin was more effective than enoxaparin in inhibiting pulmonary hypertension and vascular remodeling in hypoxic guinea pigs.     

PDTC对大鼠慢性阻塞性肺疾病血流动力学的影响

目的探讨NF-κB抑制剂吡咯烷二硫代氨基甲酸盐（PDTC）对慢性阻塞性肺病（COPD）各阶段的肺血流动力学及右心室壁厚度影响。方法将48只雄性SD大鼠随机分为八个组,分别纳入实验组及药物干预组,每组6只。实验组包括：A、B、C、D。正常对照组（A）：正常饲养4周;慢支组（B）：于实验第1、14天经气道内注入脂多糖（LPS）,200μg/次,4周后检测;COPD组（C）：第1、14天经气道内注入LPS,200μg/次,熏香烟1h/天,共4周;COPD并肺动脉高压组（D）：第1、14天经气道内注入LPS,200μg/次,熏香烟1h/天,共6周,实验的最后两周在熏香烟的同时,给予18%低氧8h/天。PDTC药物干预组为：A1（空白对照组）、B1（慢支干预组）、C1（COPD干预组）、D1（COPD并肺动脉高压干预组）。动物模型制作同各对应组,从第3周起给各药物干预组腹腔注射PDTC,剂量100mg·kg-1.d-1。A1组从第三周起腹腔注射同PDTC剂量相同的生理盐水。各组测定气道阻力、肺血流动力学和右心室肥厚指数,对肺组织行HE染色,观测气道的病理学改变,用免疫组化检测各组肺组织中NF-κB蛋白的表达。结果 C、D组RVSP、mPAP和RV/LV＋S都明显高于A组（P〈0.05）。C1、D1组RVSP、mPAP较C组、D组明显降低（P〈0.05）。D1组的RV/LV＋S值较D组有所降低（P〈0.05）。C、D组NF-κB蛋白表达强于A、B组（P〈0.05）,C1、D1组较实验组C、D组NF-κB蛋白含量下降。结论 COPD早期已出现肺血流动力学和右心室壁厚度的变化,PDTC干预后可抑制NF-κB蛋白表达,降低早期升高的平均肺动脉压力（mPAP）和右心室收缩压（RVSP）,减轻肺血管的重构,阻止右心室壁厚度的变化。     

Prognostic significance of PaO2/PaCO2 ratio in normotensive patients with pulmonary embolism

Introduction: Risk stratification remains controversial in patients with normotensive pulmonary embolism (PE). The debate has recently focused right ventricular dysfunction detected by echocardiography or spiral computed tomography (CT) and cardiac biomarkers. Objectives: The utility of the PaO₂/PaCO₂ ratio to predict the short‐term prognosis of PE is not currently known and that is the aim of the present study. Materials and Methods: This study retrospectively enrolled 99 (34 males, 65 females, 67 ± 15 years) consecutive patients with acute PE, diagnosed by spiral chest tomography pulmonary angiography (CTPA).On admission, cardiac troponin T (cTn‐T) was measured and on CTPA both right ventricle diameter and left ventricle diameter was calculated (RV/LV ratio). During the first 24 h after admission, all the patients had initial arterial blood gas collected under room air. Receiver‐operating characteristic (ROC) analysis was performed to determine the optimal PaO₂/PaCO₂, RV/LV ratio and cTn‐T cutoff level with regard to prognosis. Results: In‐hospital mortality was 12.1% and all‐cause 90‐day mortality was 15.2%. Ten of 15 patients who died had a PaO₂/PaCO₂ ≤ 1.8 based on ROC analysis (P < 0.014).The cutoff level of PaO₂/PaCO₂ ≤ 1.8 had a high negative predictive value of 93% for mortality. Multivariable analysis revealed that PaO₂/PaCO₂ ≤ 1.8 Hazard Ratio (HR): 16.8 [95% CI: 2.6–108, P < 0.003] was the most significant independent predictor, whereas cTn‐T, pO₂ < 60 mmHg and cardiac failure were nonsignificant factors. In addition, PaO₂/PaCO₂ ≤ 1.8 showed significant survival differences for overall mortality rates in Kaplan–Meier analysis (P < 0.012). Conclusion: The PaO₂/PaCO₂ measurement is a highly useful and practical measurement to predict prognosis in patients with acute PE. Moreover, it appears to be a more accurate predictor than RV/LV ratio and cTn‐T levels in patients with normotensive PE. Please cite this paper as: Ozsu S, Abul Y, Yilmaz I, Ozsu A, Oztuna F, Bulbul Y and Ozlu T. Prognostic significance of PaO₂/PaCO₂ ratio in normotensive patients with pulmonary embolism. Clin Respir J 2012; 6: 104–111.     

Reactivity of pulmonary circulation and right ventricle function to inhaled nitric oxide in systemic sclerosis patients

Systemic sclerosis (SSc) is complicated by pulmonary hypertension and right ventricle (RV) failure in approximately 10% of the patients. Factors influencing the reactivity of pulmonary circulation to vasodilators are not established, while the examination of vasoreactivity is important in determining the treatment, because systemic administration of oral vasodilators can induce severe adverse events in nonresponders. The mechanism of RV failure in SSc is unclear and may result either from increased RV afterload or intrinsic myocardial disease. The aim of the study was to assess the reactivity of pulmonary circulation to inhaled nitric oxide (iNO) and to evaluate its influence on RV function in SSc patients with elevated right ventricle systolic pressure (RVSP). In 60 SSc patients aged 24–73 (58 females, two males; 33 patients with limited SSc and 27 with diffuse SSc), echocardiographic examination with tissue Doppler echocardiography (TDE) was performed. RV function was measured by systolic (S) and early diastolic (E) velocity of tricuspid annulus by TDE. In patients with RVSP >45 mmHg, the reactivity of pulmonary circulation was assessed by iNO test. High-resolution computerized tomography (HRCT) was performed to assess the extent of pulmonary fibrosis. Of 14 SSc subjects with elevated RVSP (13 females, one male; RVSP 47–62 mmHg), positive reaction to iNO was observed in five (RVSP decreased from 51.6 ± 3.7 to 32.24 ± 2.3 mmHg); nine patients were not reactive (RVSP 53.5 ± 5.7 mmHg before iNO vs. 49.6 ± 6.7 mmHg). RV systolic function was decreased in patients with elevated RVSP as compared to the patients with normal pulmonary pressure (S velocity 13.2 ± 1.3 vs. 14.4 ± 1.6 cm/s, respectively, p < 0.05). Significant increase of RV systolic function during iNO test was found in reactive patients only (S velocity before iNO 12.8 ± 1.2 cm/s, during iNO 14.5 ± 1.5 cm/s, p < 0.01). RVSP decrease strongly correlated with S velocity increase (r = 0.95, p < 0.0001). Response to iNO was found only in limited form of SSc; diffuse SSc patients showed no response. Pulmonary fibrosis on HRCT was more frequent in subjects nonreactive to iNO (67% of patients) than in the reactive group (40% of patients). The reactivity of pulmonary circulation to iNO in SSc patients with elevated RVSP was found predominantly in limited form of the disease. Pulmonary fibrosis typical for diffuse SSc was more frequent in nonreactive subjects. Elevated pulmonary pressure plays an important role in RV systolic dysfunction. Pulmonary pressure decrease during iNO test leads to the improvement of RV systolic function. Therapy for right-heart failure in reactive SSc patients should be directed, if possible, at the decrease in pulmonary resistance.     

Melatonin reduces cardiac remodeling and improves survival in rats with isoproterenol‐induced heart failure

Melatonin was previously shown to reduce blood pressure and left ventricular (LV) remodeling in several models of experimental heart damage. This study investigated whether melatonin prevents LV remodeling and improves survival in isoproterenol‐induced heart failure. In the first experiment, four groups of 3‐month‐old male Wistar rats (12 per group) were treated for 2 wk as follows: controls, rats treated with melatonin (10 mg/kg/day) (M), rats treated with isoproterenol (5 mg/kg/day intraperitoneally the second week) (Iso), and rats treated with melatonin (2 wk) and isoproterenol (the second week) in corresponding doses (IsoM). In the second experiment, 30 rats were treated with isoproterenol and 30 rats with isoproterenol plus melatonin for a period of 28 days and their mortality was investigated. Isoproterenol‐induced heart failure with hypertrophy of the left and right ventricles (LV, RV), lowered systolic blood pressure (SBP) and elevated pulmonary congestion. Fibrotic rebuilding was accompanied by alterations of tubulin level in the LV and oxidative stress development. Melatonin failed to reduce the weight of the LV or RV; however, it curtailed the weight of the lungs and attenuated the decline in SBP. Moreover, melatonin decreased the level of oxidative stress and of insoluble and total collagen and partly prevented the beta‐tubulin alteration in the LV. Most importantly, melatonin reduced mortality and prolonged the average survival time. In conclusion, melatonin exerts cardioprotective effects and improves outcome in a model of isoproterenol‐induced heart damage. The antiremodeling effect of melatonin may be of potential benefit in patients with heart failure.     

ZD1611, an orally active endothelin-A receptor antagonist, prevents chronic hypoxia-induced pulmonary hypertension in the rat.

Endothelin-1 (ET-1) is a potent vasoconstrictor and comitogen implicated in the pathogenesis of pulmonary hypertension (PH). We evaluated the effects of an ET(A)receptor-selective antagonist, ZD1611, on hypoxia-induced PH in rats. and paradigms were established in which rats were administered placebo or ZD1611 (1-3 mg/kg, q.i.dpo) concomitant with hypoxic exposure (10% O(2)1 ATM) for 14 days or beginning after 7-day hypoxic exposure for 21 days. Compared with normoxic controls, hypoxic exposure plus placebo increased (P<0.05) hematocrit, mass ratio of right ventricle over left ventricle plus septum (RV/LV+S), and right intraventricular peak systolic pressure (RVSP). These latter two effects were decreased (P<0.05) by ZD1611 in both experimental paradigms [RV/LV+S(%)::RVSP(%); prophylactic, 14::32; therapeutic, 28::37]. Hypoxic exposure did not change mean systemic arterial pressure (MSAP). ZD1611 did not affect MSAP, plasma ET-1 concentrations, or blood gases measured when rats respired room air. In mechanistic studies, ZD1611 decreased (P<0.01) smooth muscle hypertrophy of small pulmonary arteries and abolished hypoxia-induced decreases in sensitivity and maximum contraction to ET-1 in isolated extralobar branch pulmonary artery. In conclusion, the ET(A)receptor-selective antagonist, ZD1611, attenuates hypoxia-induced PH in the rat.     

慢性低氧性肺动脉高压大鼠肺动脉内PTEN蛋白表达的变化

目的 通过观察慢性低氧性肺动脉高压大鼠肺动脉内人第10号染色体缺失的磷酸酶及张力蛋白同源的基因（PTEN）蛋白表达水平的变化,初步探讨PTEN在慢性低氧性肺动脉高压的发生、发展过程中所起的作用.方法 将6周龄健康雄性SD大鼠,随机分为正常对照组、低氧1d、3d、7d、14d和21d组,除对照组外,其他各组先建立慢性低氧肺动脉高压大鼠模型,然后检测各组大鼠右心室收缩压（right ventricle systolic pressure,RVSP）和右心室肥厚指数（right ventricle hypertrophy index,RVHI）,采用HE染色观察肺动脉病理学改变,采用Western blot技术检测肺动脉内PTEN蛋白的表达水平.结果 ①与正常对照组（23.76±0.82）mmHg相比,低氧暴露1d、3d、7d、14 d、21d后RVSP均明显上升（P＜0.05）;RVHI低氧3d、7d、14 d、21d组均较正常对照组（100％）明显上升（P＜0.05）;低氧暴露3d、7d和21d组肺动脉中膜明显增厚、管腔明显变小.②PTEN和p-PTEN在正常对照组和低氧各组均有表达.低氧各组肺动脉内PTEN蛋白的表达较对照组下降,但差异无统计学意义（P＞0.05）;而p-PTEN蛋白与PTEN总蛋白表达量的比值随低氧时间的延长有上升趋势,且在慢性低氧21d组（1.71±0.25）较正常对照组（1.00）明显增高（P＜0.05）.结论 PTEN蛋白表达的降低和p-PTEN蛋白表达的增高可能参与了大鼠慢性低氧性肺动脉高压的发生和发展过程.     

Melatonin attenuates neurogenic pulmonary edema via the regulation of inflammation and apoptosis after subarachnoid hemorrhage in rats

Neurogenic pulmonary edema (NPE) is a serious non‐neurological complication that can occur after a subarachnoid hemorrhage (SAH) and is associated with decreased survival and a poor neurological outcome. Melatonin is a strong antioxidant that has beneficial effects against SAH in rats, including reduced mortality and reduced neurological deficits. The molecular mechanisms underlying these clinical effects in the SAH model, however, have not been clearly identified. This study was undertaken to determine the influence of melatonin on SAH‐induced NPE and the potential mechanism of these effects using the filament perforation model of SAH in male Sprague Dawley rats. Either melatonin (150 mg/kg) or a vehicle was given via an intraperitoneal injection 2 hr after an SAH induction. Lung samples were extracted 24 hr after SAH. The results show that the melatonin treatment attenuated SAH‐induced NPE by preventing alveolar–capillary barrier dysfunctions via inhibiting the disruption of tight junction proteins (ZO‐1 and occludin). Moreover, the treatment downregulated the levels of mature interleukin (IL) ‐1β, myeloperoxidase (MPO), and matrix metallopeptidase (MMP) 9 expression/activation, which were increased in the lung; also, melatonin treatment improved neurological deficits. Furthermore, the melatonin treatment markedly reduced caspase‐3 activity and the number of TUNEL‐positive cells in the lung. Taken together, these findings show that administration of melatonin attenuates NPE by preventing alveolar–capillary barrier dysfunctions via repressing the inflammatory response and by anti‐apoptosis effects after SAH.     

Melatonin alleviates brain injury in mice subjected to cecal ligation and puncture via attenuating inflammation,apoptosis, and oxidative stress: the role of SIRT1 signaling

Sepsis is a systemic inflammatory response to infection that causes severe neurological complications. Previous studies have suggested that melatonin is protective during sepsis. Additionally, silent information regulator 1 (SIRT1) was reported to be beneficial in sepsis. However, the role of SIRT1 signaling in the protective effect of melatonin against septic encephalopathy remains unclear. This study aimed to investigate the role of SIRT1 in the protective effect of melatonin. EX527, a SIRT1 inhibitor, was used to reveal the role of SIRT1 in melatonin's action. Cecal ligation and puncture or sham operation was performed in male C57BL/6J mice. Melatonin was administrated intraperitoneally (30 mg/kg). The survival rate of mice was recorded for the 7‐day period following the sham or CLP operation. The blood–brain barrier (BBB) integrity, brain water content, levels of inflammatory cytokines (TNF‐α, IL‐1β, and HMGB1), and the level of oxidative stress (superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA)) and apoptosis were assessed. The expression of SIRT1, Ac‐FoxO1, Ac‐p53, Ac‐NF‐κB, Bcl‐2, and Bax was detected by Western blot. The results suggested that melatonin improved survival rate, attenuated brain edema and neuronal apoptosis, and preserved BBB integrity. Melatonin decreased the production of TNF‐α, IL‐1β, and HMGB1. Melatonin increased the activity of SOD and CAT and decreased the MDA production. Additionally, melatonin upregulated the expression of SIRT1 and Bcl‐2 and downregulated the expression of Ac‐FoxO1, Ac‐p53, Ac‐NF‐κB, and Bax. However, the protective effects of melatonin were abolished by EX527. In conclusion, our results demonstrate that melatonin attenuates sepsis‐induced brain injury via SIRT1 signaling activation.     

波生坦抑制低氧介导的大鼠肺动脉中5-羟色胺转运体的过度表达

目的 观察5-羟色胺转运体（5-HTT）在低氧性肺动脉高压（HPH）大鼠肺动脉中的表达,探讨波生坦对其肺动脉中5-HTT表达的影响.方法 30只雄性SD大鼠随机分为对照组（C组）、低氧组（H组）和波生坦组（B组）（每组10只）.C组于正常环境中饲养3周,其余2组置于低压低氧舱中饲养3周.B组大鼠予以波生坦100mg·kg^-1·d^-1灌胃,H组按体质量同体积蒸馏水灌胃.测定各组大鼠的平均肺动脉压力（mPAP）、右心室收缩压（RVSP）.免疫组织化学和Western-blot方法分别观察和测定大鼠肺动脉和肺组织中5-HTT的表达水平.结果 H组大鼠的mPAP和RVSP明显高于C组（P值均＜0.05）;和H组大鼠相比,B组大鼠mPAP和RVSP均显著降低（P值均＜0.05）.免疫组织化学和Western-blot结果显示：和C组相比,H组大鼠肺动脉和肺组织中5-HTT的表达明显升高,而B组大鼠肺动脉和肺组织中5-HTT的表达明显低于H组.结论 HPH大鼠肺动脉和肺组织中5-HTT呈过表达,而波生坦可以显著抑制低氧介导的大鼠肺动脉和肺组织中5-HTT的表达增多,这可能是波生坦的新的药理机制之一.     

In vitro and in vivo antitumor activity of melatonin receptor agonists

Abstract: Melatonin has been shown to inhibit the proliferation of estrogen receptor α (ERα)‐positive human breast cancer cells in vitro and suppress the growth of carcinogen‐induced mammary tumors in rats. Melatonin’s antiproliferative effect is mediated, at least in part, through the MT1 melatonin receptor and mechanisms involving modulation of the estrogen‐signaling pathway. To develop melatonin analogs with greater therapeutic effects, we have examined the in vitro and in vivo antimitotic activity of two MT1/MT2 melatonin receptor agonists, S23219‐1 and S23478‐1. In our studies, both agonists are quite effective at suppressing the growth of MCF‐7 human breast cancer cells. At a concentration of 10^?6 m , S23219‐1 and S23478‐1 inhibited the growth of MCF‐7 cells by 60% and 73%, respectively. However, S23478‐1 is more effective than melatonin and S23219‐1 at repressing the expression and transactivation of the ERα, and modulating the expression of pancreatic spasmolytic polypeptide (pS2), an estrogen‐regulated gene. The melatonin agonist S23478‐1 exhibited enhanced antitumor potency in the subsequent studies in our animal model. At a dosage of 25 mg/kg/day, S23478‐1 is more efficacious than melatonin at inducing regression of the established N‐nitroso‐N‐methyl‐urea‐induced rat mammary tumors. This dose of S23478‐1 (25 mg/kg/day) generated a significant (P < 0.05) overall regression response of 52%. Furthermore, at this dosage, S23478‐1 is more effective than melatonin at suppressing the estrogen‐signaling pathway and promoting tumor cell apoptosis, significantly increasing the expression of the pro‐apoptotic protein Bax, while decreasing the expression of ERα and the anti‐apoptotic protein Bcl‐2.