脑钠肽与急性心肌梗死的研究进展

脑钠肽是心肌细胞分泌的一种循环激素。左心室的牵张和心室壁张力的增加对BNP的合成和分泌起主要调节作用;心肌缺血也是BNP释放的重要触发因素之一。对BNP水平进行分级能够很好的对急性心肌梗死进行危险分层,对诊断、预后的评估有重要意义。本文就脑钠肽的特性及与心肌梗死的关系做一综述。     

脑钠肽临床应用进展

脑钠肽(brain natriuretic peptide,BNP)是近年倍受关注的心血管生物标记物,BNP是一种主要由心脏分泌的肽类激素,在心脏维持其正常结构和功能的中起着重要的作用,它具有利钠、利尿、扩血管、降压、拮抗RAAS系统、抑制交感神经兴奋等作用.它已超过原来仅作为心衰的诊断检测指标范畴.研究表明BNP与呼吸困难的鉴别诊断、心肌梗死、高血压、心房颤动、心肌病、肺栓塞等关系密切,现就BNP的临床研究进展作一综述.     

N末端脑钠肽前体在围冠状动脉搭桥术期的变化及意义

N-末端脑钠肽前体(N-terminal pro brain natriuretic peptide,NT-proBNP)是体内脑钠肽前体(proBNP)裂解成脑钠肽(brain natriuretic peptide,BNP)时的产物,NT-proBNP的血浆浓度及稳定性比BNP更高,半衰期更长,属于钠尿肽系统的重要一员,本身无生物学活性。NT-proBNP主要由正常的心肌细胞合成和分泌,在心肌损伤或坏死后迅速升高,可反映机体代偿病理改变和恢复循环的能力,是心功能障碍性疾病,如心力衰竭、左室肥厚等诊断、疗效监测和预后评估等最佳的心肌标志物,临床通过测定血浆NT-proBNP水平用于急慢性充血性心力衰竭(congestive heart failure,CHF)的诊治及预后,本文主要就NT-proBNP在围冠状动脉搭桥术(Coronary Artery Bypass Grafting,CABG)期的变化及临床意义的新进展进行综述。     

肺炎合并心力衰竭患者血浆BNP,cTn1的变化及其临床意义

目的:探讨血浆脑钠肽(BNP)和心肌肌钙蛋白(cTn1)在肺炎合并心力衰竭患者血浆脑钠肽(BNP)和心肌肌钙蛋白(cTn1)的变化情况及、肺炎未合并心衰患者及健康对照组中的不同表达,探讨血浆脑钠肽(BNP)和心肌肌钙蛋白(cTn1)与疾病变化的关系及在肺炎合并心力衰竭中的临床诊断的意义.方法:回顾性分析我院自2010年1月至2012年1月收治的42例肺炎合并心衰患者,同期收治的肺炎末合并心衰患者34例为阳性对照组,以及同期在门诊进行体检的30例健康患者为阴性对照组.在入院后24h之内评估心脏功能并检测血浆BNP及cTn1水平变化,以及心衰合并肺炎患者入院24h急性期及心衰恢复期BNP和cTn1水平的变化,比较BNP和cTn1在的不同表达.结果:心衰组、阳性对照组、阴性对照组患者BNP(378.14,142.53,0.74±0.15)和cTn1 (0.84,0.32,0.18)比较,在统计学上具有显著性意义(H=140.67,H=30.14,P＜0.001).心衰急性期与心衰恢复期BNP(378.14,140.32)和cTn1(0.84,0.04)水平比较,在统计学上具有显著性差异(t=2.044,t=2.051,P＜ 0.05).结论:BNP与cTn1在肺炎合并心衰患者为高表达,显著高于肺炎未合并心衰患者,合并心衰与未合并心衰组的BNP与cTn1水平也显著高于健康对照组,表明BNP与cTn1的表达与病情呈正相关.且在肺炎合并心衰急性期的表达高于恢复期,表明BNP、cTnⅠ水平变化可为诊断患者病情严重程度及肺炎合并心衰为急性期或慢性提高依据,可以为早期心功能衰竭提高临床参考.     

N 端脑钠肽前体在心血管疾病中的研究进展

N端脑钠肽前体(NT-proBNP)为脑钠肽(BNP)生成过程中产生的无活性肽段残片,其与BNP等摩尔量分泌。近年来,NT-proBNP的检测在心血管领域的作用越来越得到国内外学者的关注。NT-proBNP在心血管疾病的诊断、预后、分级等方面都具有重要的价值。本文主要介绍NT-proBNP在心血管疾病中的研究进展。     

血浆B 型脑钠肽对急性冠脉综合征的病情影响及预后评估

目的:探讨血浆B型脑钠肽(BNP)对急性冠脉综合征的病情影响及预后评估的作用,为临床实践提供参考.方法:分别对30例健康体检者(对照组)和81例ACS患者(观察组)检测其入院24小时内的血浆BNP浓度,并在住院一周内行冠状动脉造影术,检查病变的冠脉支数.结果:观察组的血浆BNP浓度高于对照(P＜0.01),病变动脉支数与BNP水平呈正相关(P＜0.01).结论:BNP是急性冠脉综合征发病的重要因素,其水平高低可反映病情的严重程度,是预测病情和预后的重要指标.临床上应有效的监测BNP水平,对正确诊断和有效治疗急性冠脉综合征具有重要的意义.     

急性心肌梗死患者早期血浆脑钠肽水平与左室重构及预后关系的评估

目的:探讨急性心肌梗死(AMI)早期脑钠肽(BNP)水平与左室重构及预后的关系.方法:用放射免疫法测定AMI患者早期血浆BNP水平;用超声心动图检查测量左室收缩末容积(ESV)、左室舒张末容积(EDV)、射血分数(EF)并通过计算得左室质量(LVM).并根据左心室容积指标分组,左心室容积增加率＞20%为左心室重构组,否则为非重构组,比较两组血浆BNP水平.结果:重构组恢复期左心室舒张末期及收缩末期容积指数均高于非重构组(P＜0.01),亦高于急性期左心室容积(P＜0.01).重构组早期血浆BNP浓度明显高于非重构组(P＜0.01),恢复期也较非重构组高(P＜0.01).重构组早期BNP浓度与恢复期左心室容积及容积变化量之间呈正相关.结论:AMI早期BNP升高与急性期左室重构密切相关,血浆BNP浓度可以作为溶栓治疗再通的观察指标及预后判断依据.     

GATA结合蛋白4在心脏发育及心肌重塑中的作用

转录因子GATA结合蛋白4(GATA-binding protein 4, GATA-4)在心脏发育和心肌重塑过程中发挥重要的调控作用.GATA-4基因缺失可致胚胎死亡,而不同位点的错义突变将引起不同类型的先天性心脏发育畸形.GATA-4蛋白表达水平降低可导致心脏功能进行性下降.压力超负荷、缺氧、交感神经激活等各种心肌肥厚刺激因素均可显著影响GATA-4的DNA结合活性,进而通过调控心房利钠肽(ANP)、脑利钠肽(BNP)、B细胞淋巴瘤因子2(Bcl-2)、心肌锚定重复序列蛋白(CARP)等多种心肌重塑相关转录因子的表达参与心肌重塑过程.深入探讨GATA-4的转录调控机制,有望为心血管疾病的防治提供新的线索.本文扼要综述GATA-4在心脏发育及心肌重塑中的研究现状.     

心脏瓣膜疾病患者术后危险因素及潜在预测指标初探

目的:评价心肌肌钙蛋白(cardiac troponin,c Tn T)、氨基末端脑钠肽前体(N-terminal pro·-brain natriuretic peptide,NT-pro BNP)对于心瓣膜疾病手术患者术后并发症的预测价值。方法:选取我院2014年1月~2015年12月收治的心瓣膜病患者共108例,入院即记录其年龄、性别、BMI指数、NYHA等,于患者出院1个月后开始随访,随访时间为18个月,根据随访结局分为预后良好组与预后不良组。生存曲线显示随访后的不良预后率;单因素、多因素Cox回归评价各因素对患者预后情况的影响程度;ROC曲线分析其对疾病预后的预测价值。结果:多因素Cox回归分析显示左心室舒张末期内径(left ventricular end-diastolic dimension,LVEDD)(P=0.022)、c Tn T(P=0.023)和NT-pro BNP(P=0.016)对患者术后不良预后存在影响,其中,LVEDD的影响程度最高(RR=2.142),其次为NT-pro BNP(RR=2.046);ROC曲线下NT-pro BNP联合c Tn T预测的AUC为0.856,其特异性为83.6%,敏感性为79.3%。结论:NT-pro BNP联合BNP对心瓣膜置换术后患者的预后有较好的预测价值。     

基质细胞衍生因子-1 与围生期心肌病患者心力衰竭的相关性研究

目的:探讨基质细胞衍生因子-1与围生期心肌病患者心力衰竭的相关性。方法:采用前瞻性研究纳入59例围生期心肌病并发心力衰竭患者,33例单纯围生期心肌病患者作为对照组。患者均接受体检、实验室检查、心电图、心脏彩超评估。选取基质细胞衍生因子-1(SDF-1)、超敏C反应蛋白(hs-CRP)、氨基末端脑钠肽前体(NT-pro BNP)、血清肌钙蛋白(TNI)及心脏彩超相关参数为评价指标。结果:(l)围生期心肌病患者循环中基质细胞衍生因子-1水平明显高于对照组;(2)循环中基质细胞衍生因子-1与超敏C反应蛋白(CRP)、氨基末端脑钠肽前体(NT-pro BNP)呈正相关,与超声心动图左心室射血分数(LVEF)呈负相关。结论:基质细胞衍生因子-1与围生期心肌病患者心力衰竭具有显著相关性。     

Experimental investigations in prolonged myocardial ischaemia. Note I. Biology of the myocardial fiber after transient myocardial fiber after transient myocardial ischaemia

The first ten days' evolution of post-ischaemic lesions of the premonitory or angina pectoris syndrome type was experimentally studied by the challenge of a short-term (10 and 15 min) ischaemia, of an adaptation to ischaemia and an adaptation followed by prolonged ischaemia (20 and 35 min). Worthy of note was the persistence of reversible lesions after short-term ischaemia and adaptation, and the progressive evolution towards cytolysis and cicatrization of some pancicellular foci after adaptation followed by prolonged ischaemia. The role of mitochondrial lesions, of lysosomal hydrolases, the inefficiency of renewed circulation, as well as problems of diagnosis are discussed.     

Pregnancy-related myocardial infarction

Introduction

The risk of acute myocardial infarction in young women is low, but increases during pregnancy due to the physiological changes in pregnancy, including hypercoagulability. Ischaemic heart disease during pregnancy is not only associated with increased maternal morbidity and mortality, but also with high neonatal complications. Advancing maternal age and other risk factors for cardiovascular diseases may further increase the risk of ischaemic heart disease in young women.

Methods

We searched the coronary angiography database of a Dutch teaching hospital to identify women with acute myocardial infarction who presented during pregnancy or postpartum between 2011 and 2013.

Results

We found two cases. Both women were in their early thirties and both suffered from myocardial infarction in the postpartum period. Acute myocardial infarction was due to coronary stenotic occlusion in one patient and due to coronary artery dissection in the other patient. Coronary artery dissection is a relatively frequent cause of myocardial infarction during pregnancy. Both women were treated by percutaneous coronary intervention and survived.

Conclusion

Physicians should be aware of the increased risk of myocardial infarction when encountering pregnant or postpartum women presenting with chest pain.

     

Dysfunction of myocardial sarcoplasmic reticulum in rats with myocardial calcification

We investigated the relationship between cardiac dysfunction and Ca2+ transport in the myocardial sarcoplasmic reticulum (SR) during the pathogenesis of cardiovascular calcification in rats. The possible mechanism of SR dysfunction was explored by detecting the alteration of the nitric oxide/nitric oxide synthase (NO/NOS) pathway in the SR. Using the vitamin D plus nicotine (VDN treatment for 2 week and 6 week) experimental model of cardiac calcification, cardiac function and sarcoplasmic reticulum function were measured. Inhibition of cardiac functions in vivo (peak rate of contraction and peak rate of relaxation, P < 0.05 or P < 0.01) were observed in all calcification groups, simultaneously, Ca2+ release and uptake in the SR as well as the Ca2+ release channel and Ca2+ pump activity were inhibited. Myocardial Ca2+ concentration and cardiac and SR dysfunction were inversely related (P < 0.05). The specific NO/NOS pathway (NO production, NOS activity and nNOS expression in the SR) was upregulated in the SR and associated with calcification (both 2- and 6 week VDN groups). These results indicate that cardiac dysfunction associated with myocardial calcification might be mediated by SR dysfunction, which may result from an impaired SR-specific NO/NOS pathway.     

Mesenchymal stem cell injection after myocardial infarction improves myocardial compliance

Cellular therapy for myocardial injury has improved ventricular function in both animal and clinical studies, though the mechanism of benefit is unclear. This study was undertaken to examine the effects of cellular injection after infarction on myocardial elasticity. Coronary artery ligation of Lewis rats was followed by direct injection of human mesenchymal stem cells (MSCs) into the acutely ischemic myocardium. Two weeks postinfarct, myocardial elasticity was mapped by atomic force microscopy. MSC-injected hearts near the infarct region were twofold stiffer than myocardium from noninfarcted animals but softer than myocardium from vehicle-treated infarcted animals. After 8 wk, the following variables were evaluated: MSC engraftment and left ventricular geometry by histological methods, cardiac function with a pressure-volume conductance catheter, myocardial fibrosis by Masson Trichrome staining, vascularity by immunohistochemistry, and apoptosis by TdT-mediated dUTP nick-end labeling assay. The human cells engrafted and expressed a cardiomyocyte protein but stopped short of full differentiation and did not stimulate significant angiogenesis. MSC-injected hearts showed significantly less fibrosis than controls, as well as less left ventricular dilation, reduced apoptosis, increased myocardial thickness, and preservation of systolic and diastolic cardiac function. In summary, MSC injection after myocardial infarction did not regenerate contracting cardiomyocytes but reduced the stiffness of the subsequent scar and attenuated postinfarction remodeling, preserving some cardiac function. Improving scarred heart muscle compliance could be a functional benefit of cellular cardiomyoplasty.     

Non-ischemic myocardial preconditioning

The reduction of infarct size produced by brief ischemic episodes prior to a sustained occlusion of a coronary artery, called ischemic preconditioning, is a well known phenomenon that occurs in several species, but its mechanism is still under investigation. Recent reports support the idea that this protection can also be obtained by non-ischemic maneuvers like distention of the left ventricle and metabolic stimulation of myocardial cells. The features of non-ischemic preconditioning (temporal limitation, second window, tolerance development, remote preconditioning and efficiency of the protection), as opposed to those of ischemic preconditioning, are still to be determined. Neither is it known if non-ischemic preconditioning occurs in humans. From a physiological point of view the protective effect of an increase in metabolic rate of the heart means a constant feed-back mechanism in the myocardial cell that counteracts the presumptive damage consequent to the increase in metabolism. Therefore, in the presence of a sudden coronary occlusion the metabolic rate of the heart immediately before the occlusion would have a dual role of increasing the degree of ischemia and of protecting against it.     

Multivessel myocardial infarction

A 56-year-old female patient with hypertension, obesity and chronic intermittent cauda equina compression suffered an acute myocardial infarction five days after a lumbar hernia operation. The electrocardiogram (ECG) showed ST-segment elevation in multiple leads, consistent with an extensive acute apical and lateral myocardial infarction (figure 1, panel A). Acute coronary angiography revealed occlusion of the end-arteries of the left coronary artery in the absence of significant atherosclerotic disease (figure 1, panel B).