【作者】 李明霞；

【导师】 穆玉明；

【作者基本信息】 新疆医科大学 ， 内科学， 2008， 博士

【摘要】 研究背景:新生儿缺氧性肺动脉高压(Hypoxia-induced pulmonary hypertension,HPH)是指新生儿出生后因各种缺氧性疾病所致的新生儿肺血管痉挛,肺循环阻力增高,最终肺动脉压升高。如果缺氧严重,患儿的肺动脉压超过体循环动脉压,引起心房及(或)动脉导管水平血液的右向左分流,临床上出现严重紫绀、低氧血症,则发展为新生儿持续肺动脉高压(persistent pulmonary hypertension of the newborn,PPHN)。新生儿HPH在临床上并不少见,其具有与成人及年长儿童不同的特点,起病急,进展快,病情危重,但积极治疗可逆转。由于其临床表现不典型,早期诊断困难。超声心动图能快捷、无创、可靠测量肺动脉压力,是一个较好的诊断方法。但国内在新生儿未普遍开展。目前有关新生儿HPH的发病机制不清,研究认为缺氧所致肺微小动脉内皮损伤,引起血管收缩因子内皮素-1(endothelin-1,ET-1)和舒张因子一氧化氮(nitricoxide,NO)之间的平衡失调,肺血管收缩,肺动脉高压发生。但针对ET-1和NO的特异有效治疗方法在新生儿受限,目前只能对症,效果欠佳。在成人HPH的研究中发现缺氧诱导因子-1α(hypoxia inducible factor-1 alpha,HIF-1α)在转录水平参与了ET-1和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)的基因表达调控,从而参与了肺动脉高压的形成机制。但在新生儿HPH的发病机制中ET-1及NO是否是通过HIF-1α激活ET-1和iNOS的基因而起作用仍不清楚。如果能发现HIF-1α和新生儿HPH的关系,从HIF-1α着手研究新的治疗方法,可能会有意义。新生儿HPH易使右心室功能受累,早期无特征性表现,待发现时救治困难。超声心动图是较好的评价早期心功能障碍的无创检查方法,常规超声检查方法在新生儿有局限性,新的超声检测方法中Tei指数被认为是评价心室整体功能有价值的指标,组织多普勒成像(tissue Doppler imaging,TDI)技术可以分别测定右心室收缩和舒张功能。但国内外对超声在评价HPH新生儿右心室功能方面的作用研究较少。如果用新的超声诊断方法能及早发现HPH新生儿右心室功能障碍,则有利于临床早期治疗,改善预后。目的:1.采用超声心动图动态监测缺氧新生儿肺动脉收缩压(pulmonary arterialsystolic pressure,PASP)的变化情况,以便及早诊治新生儿HPH。2.通过了解HPH新生儿血清HIF-1α、ET-1、iNOS水平及其mRNA及蛋白质在HPH新生儿肺组织中的表达,探讨HIF-1α及其靶基因和新生儿HPH的关系,从而推断其在发病机制中的作用,为进一步探讨新的治疗方法提供参考。3.通过比较常规超声方法、右心室Tei指数及TDI技术相关指标在评价HPH新生儿右心室功能早期变化中的作用,以期尽早发现反映HPH新生儿右心室功能损害的早期敏感指标,以便早期诊治,改善预后。方法:选取2006年6月至2008年7月在新疆医科大学第一附属医院新生儿科病房住院的足月新生儿共97例。其中病例组(HPH组)75例,对照组22例。根据肺动脉高压的程度将病例组分为三个亚组,其中轻度组29例(40mmHg≤PASP＜50mmHg),中度组25例(50mmHg≤PASP＜70mmHg),重度组21例(PASP≥70mmHg)。1.全部新生儿于生后第1、3、7d进行超声心动图测定PASP、ELASA法测定其血清HIF-1α、ET-1、iNOS浓度、左侧桡动脉血作血气分析。比较各组各时间点新生儿血清HIF-1α、iNOS、ET-1水平的差异,以及和肺动脉压力及血气分析指标的关系。2.用半定量逆转录-聚合酶链反应(reverse transcriptase-polymerase chainreaction,RT-PCR)及western blotting方法检测因HPH死亡新生儿5例及其他原因(非心肺疾病)死亡新生儿4例(9例均经家属同意)肺组织中HIF-1α、ET-1、iNOS mRNA及蛋白质的表达,比较其在HPH及非HPH死亡新生儿肺组织表达的异同。3.对上述97例新生儿进行超声心动图测定反映右心室功能的右心室射血分数(right ventricular ejection fraction,RVEF)、三尖瓣E/A值、右心室Tei指数及TDI相关指标,评价各种反映右心室功能超声指标的价值。结果:1.病例组新生儿生后第1d PASP较对照组升高,且和缺氧指征呈负相关。随缺氧症状的改善,PASP下降。其中轻、中度组生后第3d缺氧指征恢复正常,PASP到生后第7d恢复。重度组患儿至生后第7d缺氧指征恢复,而PASP仍高于对照组。2.除轻度HPH组患儿血清iNOS水平外,生后第1d病例组新生儿血清HIF-1α、ET-1、iNOS水平增高,且随PASP增高程度而加重,随缺氧改善及PASP的下降而下降。和缺氧指征呈负相关,和PASP呈正相关。HIF-1α、iNOS的恢复和缺氧指征的恢复同步,比PASP的恢复快。除轻度组外,病例组PASP和ET-1的恢复同步,慢于血清HIF-1α水平和缺氧指征的恢复。三个指标中HIF-1α和PASP及缺氧指征相关系数最大,而iNOS的变化较弱。3.重度HPH死亡患儿肺组织中HIF-1α、ET-1、iNOS的mRNA及蛋白质的表达增强。4.常规超声方法测定HPH患儿右心室功能显示生后1、3、7d重度HPH组患儿右心室收缩、舒张功能减低。5.右心室Tei指数测定结果显示病例组患儿Tei指数较对照组升高(右心室功能下降),与PASP呈正相关。缺氧症状恢复较快,PASP及右心室功能恢复慢。6.TDI技术发现HPH患儿右心室舒张功能较收缩功能更易受累,且恢复较慢。舒缩功能的变化和缺氧及PASP的变化并不完全平行。结论:1.新生儿HPH早期为缺氧引起的肺血管痉挛,及时治疗可恢复,若生后7天肺动脉压仍升高(特别是到了PPHN阶段)则救治困难。B超可及时、方便、准确地诊断新生儿HPH及PPHN。2.缺氧新生儿PASP和血清HIF-1α、ET-1、iNOS水平有关。推测缺氧可使HIF-1α水平增加,引起ET-1及iNOS增加,ET-1与NO平衡失调,肺动脉高压发生。3.重度HPH死亡患儿肺组织中HIF-1α、ET-1、iNOS的mRNA及蛋白质的表达明显增强。进一步提示HIF-1α及其靶基因(ET-1、iNOS)参与了新生儿HPH的发病。4.常规超声心动图仅发现重度HPH患儿右心室功能障碍。右心室Tei指数能敏感地发现轻、中、重度HPH患儿右心室功能障碍。TDI技术比Tei指数的优越性在于其可以多个指标分别判断右心室收缩、舒张功能改变。右心室舒缩功能改变和缺氧及PASP的变化并不完全平行,故不能仅仅依据缺氧症状判断病情,还需要用超声方法监测其肺动脉压力及右心室功能的改变情况,及时诊治。更多还原

【Abstract】 Background:Hypoxic pulmonary hypertension（HPH） for the newborn is characterised by increasing pulmonary artery pressure（PAH） because of various diseases caused by hypoxia which can lead to neonatal pulmonary vascular spasm,pulmonary vascular resistance increased,the end of PAH.If the children with pulmonary arterial pressure over systemic arterial pressure,arising right to left shunt from the atrium and（or） the blood levels of artery catheter,the persistent pulmonary hypertension for the newborn （PPHN） is developed.HPH for the newborn is common in neonate,which has different characteristics from adults and older children,because its onset is acute,progress qulckly,but prompt treatment can reversed the results.Because its clinical manifestations are not typical,early diagnosis is difficulty.Echocardiography diagnosis of pulmonary hypertension is the most important non-invasive method.At present the mechanism of the HPH is unclear.There are some reports about HPH said that,hypoxia lead to damage of vascular endothelial dysfunction,causing imbalance of vascular shrinkage factor（endothelial-1,ET-1） and diastolic factor（nitric oxide,NO）,which rolling in vascular smooth muscle,leading to the occurrence of pulmonary high pressure.However,in the pathogenesis of newborns HPH,the role of ET-1 and NO through the hypoxia inducible factor-1 alpha（HIF-1α） activating of ET-1 and inducible nitric oxide synthase（iNOS） gene is still not clear,no report related to HIF-1α,iNOS,ET-1,NO,and neonatal pulmonary artery pressure.HPH can make right ventricular function involvemem in newborns.Right ventricular dysfunction in the early clinical features is non-performance,which is difficulty in treatment.Echocardiography in the evaluation of cardiac function has been widely used,new detection method can be applied to the right ventricular function studies,which Tei index is considered the overall valuable indicators of evaluation of ventricular function,Tissue Doppler imaging（TDI） technology can be used to determine right ventricular systolic and diastolic function,But there are few relevant reports about right ventricular function in newborns with HPH.Purpose:1.To monitor the changes of pulmonary artery systolic pressure（PASP） in hypoxic neonates by using echocardiography methods,in order to getting early diagnosis of neonatal HPH and PPHN,so giving timely treatment to improve the prognosis.2.To monitor the changes of PASP in newborns with HPH and changes of indicators of blood gas analysis,changes of the serum HIF-1α,ET-1,iNOS,to understand the relationship between the HIF-1α,ET-1,iNOS and HPH neonatal PASP; To detect expression of HIF-1α,ET-1,iNOS’s mRNA and protein in lung tissue of HPH neonatal,infer the role of HIF-1αand its target genes in the pathogenesis of neonatal HPH.It provided for reference to further explore new therapies.3.To compare the role in right ventricular ejection fraction（RVEF）,tricuspid E / A value,the right ventricle Tei index and tissue Doppler imaging（TDI） related indicators in evaluating early functional changes of the right ventricle of HPH neonatal,this study could found early sensitive indicator of the right ventricular dysfunction of newborn, which provide the basis for guiding the treatment and implementation of early intervention.Methods:Ninety-seven cases of newborns were included in the present study,they were chosen completely at random from June,2006 to July 2008 in the first affiliated hospital of Xinjiang Medical university.75 cases of newborns were hypoxic pulmonary hypertension（HPH） group,while 22 cases of newborns which has other heart and lung disease without symptoms of hypoxia were control group.Group of newborns with HPH will be divided into three subgroups,including mild HPH group of 29 cases （40mmHg≤PASP＜50mmHg）,moderate HPH group of 25 cases（50mmHg≤PASP＜70mmHg）,severe HPH group of 21 cases（PASP≥70mmHg）.1.97 cases of newborns after birth in the first 1,3,7 d which were divided into the HPH three groups and the control group were conducted echocardiography of PASP respectively.While they were determined concentration of HIF-1α,ET-1,iNOS with ELASA and the left-around arterial blood for blood gas analysis.Comparing level of each group of neonatal serum HIF-1α,iNOS,ET-1difference in the three time points, and PASP、blood gas analysis indicators of changes in serum HIF-1α,ET-1,iNOS changes,understand the relevance of HIF-1α,ET-1,iNOS and HPH neonatal PASP and indicators of blood gas analysis.2.By semi-quantitative reverse transcriptase-polymerase chain reaction（RT-PCR） method and western blotting to detect HIF-1α,ET-1,iNOS mRNA and protein expression in the lung tissue,from HPH five cases of neonatal deaths and other reasons （Non-heart and lung diseases） four cases of neonatal deaths（nine cases have been family members agreed）,which compared HIF-1α,ET-1,iNOS mRNA and protein expression of the similarities and differences between HPH and non-HPH neonatal lung tissue.3.The same way on these 97 cases of newborns were conducted by echocardiography to detect indicators of right ventricular function in traditional ultrasound,the right ventricle Tei index and TDI relevant indicators,in order to evaluate various value of responding right ventricuiar function.Results:1.PASP of three case groups after 1 day are higher than in the control group,and PaO₂,PaO₂/FiO₂ was negatively correlated.With the improvement of symptoms of hypoxia,PASP decreased.To mild to moderate group with the first 3 day after birth, hypoxia pointer return to normal,PASP resume in No.7 day after birth.To severe group, hypoxia pointer restore to normal in No.7 day after birth,PASP is still higher than normal.2.HIF-1α,ET-1 levels of three case group increased significantly first day after birth,（in addition to levels of iNOS in the mild group）,and aggravated with the increased level of PASP.It was a negative correlation with PaO₂,PaO₂/FiO₂,and was positively related PASP.With the improvement of hypoxia and decline of PASP,HIF-1αwas lower in serum levels,which its recovery was synchronization with recovery of hypoxia indicators,quicker than the recovery of PASP.In addition to the mild group,the recovery of PASP and ET-1 level was sync,slower than the serum levels of HIF-1αand the resumption of hypoxia indication.Correlation coefficient of three indicators in the HIF-1α,PASP and hypoxia indication was biggest,relative to HIF-1αand ET-1,change of iNOS level was weaker.3.The mRNAs and protein of HIF-1α,ET-1,iNOS from Lung died of severe HPH patients were clearly expressed.4.With conventional ultrasound method measured,right ventricuiar function of HPH newborn showed that systolic and diastolic function of right ventricuiar reduced after one day,three days,and seven days at severe HPH group.5.Tei index of the right ventricle showed that Tei index in case groups of were higher than the control group,overall function of the right ventricle decreased,PASP and Tei index of right ventricular was positively related,changes was sync,hypoxia symptoms resumed faster,while PASP and function of right ventricular recovered slow.6.TDI technology found that diastolic function of the right ventricle was more involved,and the resumption of slow,even after the restoration of the pulmonary artery pressure;Function changes of systolic and diastolic,lack of oxygen and changes of pulmonary artery pressure is not completely parallel.Conclusion:1.Neonatal HPH is hypoxia-induced pulmonary vascular spasm in the early time, which can resume by treatment timely,but if the pulmonary artery pressure is still high in 7 days after birth（especially in the stage PPHN）,is difficulty in treatment. Echocardiography can be used convenient,timely and accurate to diagnosis of neonatal HPH and PPHN.2.HPH was correlated to HIF-1α,ET-1,iNOS level in serum.We can speculate that hypoxia can improve a expression of HIF-1a,causing increase of ET-1 and iNOS, leading to balance disorders in ET-1 and NO,HPH occurred,so it is involved in the pathogenesis of neonatal HPH3.The mRNAs and protein of HIF-1α,ET-1,iNOS from Lung died of severe HPH patients were clearly expressed.So inferred that hypoxia activate HIF-1αexpression in the activation of the transcription level ET and iNOS of gene expression,which participates in pathogenesis of pulmonary hypertension.4.Conventional echocardiography can be found severe HPH newborn with right ventricular dysfunction.Tei index of right ventricle can be sensitive to discovery right ventricular dysfunction in HPH newborn,.The superiority of TDI technology were able to determine right ventricular systolic and diastolic function change than Tei index in its many targets,and the changes of Systolic and diastolic function is not completely parallel with hypoxia and PASP.So illness can not be judged only on the basis of hypoxia symptoms,it is need to use ultrasound to monitor changes about pulmonary artery pressure and function of right ventricular,timely diagnosis and treatment.更多还原