心源性猝死患者心肌CX43和C-JUN表达及意义

目的:探讨心源性猝死者心肌细胞中连接蛋白(connexin CX)CX43和原癌基因蛋白(C-JUN)的表达及意义.方法:从2008-2011年青岛市市立医院病理科现有的蜡块中选取心性猝死者40例.其中冠心病22例,肺动脉栓塞10例,病毒性心肌炎5例,扩张性心肌病3例,选取因交通事故、外伤等死亡的病例10例作为对照组.应用免疫组织化学的方法分别检测各组病例中心室肌细胞中C-JUN和CX43蛋白的表达.结果:心源性猝死(SCD)组中心肌细胞中C-JUN的表达明显高于对照组(P＜0.01).而心性猝死组中CX43的表达却低于对照组.SCD组中心肌细胞中C-JUN与CX43的表达正相关(r=0.315,P=0.022).结论:SCD患者心肌细胞中CX43表达和分布异常,结构的重塑导致了致死性心律失常的反生,SCD患者心肌中C-JUN高表达,且与CX43蛋白的表达呈正相关,提示二者可能共同参与了SCD的发生发展,不仅可以用于临床相应药物的研发,还可能称为法医学上对SCD的鉴别提供辅助指标.     

低频脉冲磁场对大鼠心肌微血管内皮细胞增殖和缝隙连接蛋白43表达的影响

目的:探讨低频磁场对大鼠心肌微血管内皮细胞(CMECs)增殖和缝隙连接蛋白43(Cx43)表达的影响.方法:设不同照射强度为(08.mT组,1.4mT组,1.8mT组)为照射组.不加磁场干预为对照组.照射条件;磁场频率为15Hz,强度分别为0.8mT、1.4mT、1.8mT,照射时间为4 h/d,连续照射7d.应用MTT法检测CMECs增殖,采用Western blot检测Cx43蛋白表达.结果:生长曲线结果显示,磁场能够促进CMECs增殖.1.4mT组照射第2d后CMECs生长速度加快,在第3d开始进入对数生长期,在第4d生长最为旺盛之后进入生长平台期,第2～7d与对照组比较有显著性差异(P＜0.05),而且细胞生长曲线明显前移并且峰值增高.1.4mT组、1.8mT组CMECs增殖与对照组比较显著升高(P＞0.05).磁场照射后Cx43表达明显上调,1.4mT组、1.8mT组Cx43蛋白的表达均明显上升,与对照组比较差异有统计学意义(P＜0.05),0.8mT组cx43蛋白的表达与对照组比较无显著性差异(P＞0.05).而Cx43蛋白的表达1.4 mT组和1.8mT组之间差异无统计学意义(P＞0.05).结论:低频脉冲磁场能促进CMECs增殖与增强细胞活力,上调Cx43表达,其在分子水平上的可能作用机制表现为对Cx43的有效调控.     

H.pylori对MGs胃黏膜Cx32、Cx43及相关转录因子表达的影响

目的观察幽门螺杆菌(Helicobacter pylori,H.pylori)对蒙古沙土鼠(Mongolian gerbils,MGs)胃黏膜Cx32、Cx43和转录因子GATA-3、AP-4、PBX-1、C/EBPβ表达的影响及其相关性,探讨H.pylori致癌的机制。方法实验组采用经胃镜及病理确诊的胃癌患者胃黏膜分离的H.pylori对36只MGs灌胃,对照组5只用灭菌PBS灌胃;分批处死,观察H.pylori灌胃后第4、24、48、72周MGs H.pylori定植和胃黏膜病变情况,及Cx32、Cx43和转录因子表达变化。结果实验组H.pylori定植率为80.0%,灌胃后第4、24周MGs胃黏膜肉眼见充血水肿或糜烂、出血,HE染色呈不同程度慢性非萎缩性胃炎(NAG),48周后6例肉眼见胃黏膜变薄、颜色灰暗,HE染色4例慢性萎缩性胃炎(CAG)、2例肠化(IM),对照组无H.pylori定植,胃黏膜肉眼及HE染色无明显异常;实验组较对照组MGs胃组织Cx32、Cx43表达显著下降,转录因子GATA-3、AP-4、PBX-1、C/EBPβ表达显著升高(P0.05),其中有胃癌前病变(CAG和IM)者较NAG者改变明显(P0.05);Cx32、Cx43与转录因子表达呈负相关(-1r0,P0.05)。结论 H.pylori感染上调MGs胃黏膜转录因子GATA-3、AP-4、PBX-1和C/EBPβ表达,下调Cx32、Cx43表达,可能与胃癌发生有关。     

人HCN4通道的滞后现象:影响窦房结起搏的潜在决定因素(英文)

超极化活化环核苷酸门控(hyperpolarization-activated cyclic-nucleotide-gated,HCN)通道参与调制心脏跳动的节律和速率。与HCN1和HCN2有所不同,慢通道HCN4可能不存在电压依赖的滞后现象。本研究采用单细胞膜片钳方法,在稳定转染hHCN4的HEK293细胞上进行电生理记录,观察hHCN4通道是否存在滞后现象,以及cAMP对其的调制作用;同时采用实时定量RT-PCR方法检测窦房结和心房组织中HCNs的表达。电压钳实验结果显示hHCN4电流(Ih)激活随着保持电位超极化的变化而向去极化方向移动。三角电位变化钳(triangular ramp)和动作电位钳的结果也显示了hHCN4的滞后现象。cAMP增加Ih电流幅度,且使电流激活向去极化方向移动,从而改变内源性hHCN4滞后行为。RT-PCR结果显示,人窦房结组织主要表达HCN4,占75%,HCN1占21%,HCN2占3%,HCN3占0.7%。以上结果提示,人窦房结组织主要表达HCN4亚型,hHCN4的Ih存在电压依赖性的滞后现象,且受cAMP调制。由此推断,hHCN4通道的滞后现象可能在窦房结起搏活动中起到了关键作用。     

36 例心源性猝死尸检的临床病理学研究*

目的:分析心源性猝死的临床病理学特征,为心源性猝死的诊断和预防提供理论依据。方法:收集36例心源性猝死病例的尸检解剖资料,进行病理组织学检查。结果:36例心源性猝死者中,冠心病21例,占心源性猝死者总数的58.33%;心律失常性右心室心肌病猝死者3例,占心源性猝死者总数的8.33%。结论:科学系统的尸检可以明确猝死原因,为医疗纠纷鉴定提供可靠依据,同时,对提高医疗质量,早期诊断、治疗心血管系统疾病和减少猝死发生起有重要作用。     

低氧对大鼠右心室肥厚及心肌中缝隙连接蛋白43表达的影响

目的:研究低氧对大鼠右心室肥厚及心肌中缝隙连接蛋白43 (Cx43)表达的影响.方法:40只健康雄性SD大鼠随机分为正常组(control)、低氧3周组、低氧4周组和低氧5周组.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5周.测定和比较各组大鼠的平均肺动脉压力(mPAP)、右心室收缩压(RVSP)、右心室肥厚度[Rv/(LV+S)％],并通过免疫组化染色法观察各组大鼠左心室心肌细胞中cx43的表达.结果:与正常组相比,低氧3周、4周、5周组大鼠的mPAP、RVSP、右心室肥厚度均显著升高(P均＜0.05),与低氧3周组比较,低氧4周、5周组大鼠的mPAP、RVSP、右心室肥厚度均显著升高(P均＜0.05),而低氧5周组大鼠的mPAP、RVSP、右心室肥厚度均显著高于低氧4周(P均＜0.05).免疫组织化学结果显示:低氧组大鼠Cx43排列紊乱,端-端连接减少,侧面连接增多;随着低氧时间的延长,大鼠心肌细胞中Cx43的表达逐渐减少,差异具有统计学意义(P均＜0.05).结论:低氧可导致右心室肥厚,并随着诱导时间的延长而逐渐加重,这可能与心肌中Cx43的分布紊乱及表达减少有关.     

心脏性猝死者心肌HO-1 和VEGF 的表达及意义

目的:探讨血红素加氧酶-1(hemeoxygenase-1,HO-1)、血管内皮生长因子(vascularendothelial growthfactor,VEGF)在心脏性猝死病人心室肌细胞中的表达及其意义.方法:运用免疫组织化学方法和Simple PCI图像分析系统观察33例心脏性猝死组和18例非心脏性猝死对照组尸检心肌组织中HO-1、VEGF蛋白的表达情况.结果:心脏性猝死组心肌组织HO-1(155.090±8.957)和VEGF蛋白表达(121.020±10.927)均显著高于非心脏性猝死对照组(116.200±6.355、84.207±4.402,均p<0.05).结论:HO-1和VEGF蛋白在心脏性猝死者心肌组织表达增强,可能与心脏性猝死有一定关系.

Abstract：

Objective: To investigate expression of the heine oxygenaso-1 (HO-I )and vascular endothelial growth factor (VEGF)in the left ventricle in patients with sudden cardiac death (SCD). Methods: Immunohistoehernistry and Simple PCI image analysis system were used to detect the expressions of riO-1 and VEGF in 33 eases of SCD and 18 eases of non SCD (control group). Results: The expressions of HO-1( 155.090± 8.957) and VEGF(121.020± 10.927) in the myoeardium of patients in SCD group were significantly higher than those in control group (116.200± 6.355, 84.207± 4.402 ,all p<0.05). Conclusions: The high expression of HO-1 and VEGF may be related with the sudden cardiac death to some extent.     

QRS、QT、QTc及LVEF预测心源性猝死的价值分析

摘要 目的：探讨QRS时限值（QRS）、QT间期延长（QT）、QTc间期（QTc）及左室射血分数（LVEF）预测心源性猝死的价值分析。方法：选择2018年1月至2019年12月川北医学院附属医院心血管内科治疗的356例心源性猝死患者进行研究,设为病例组,并选择同期体检的健康人200例作为对照组,分析QRS、QT、QTc及LVEF水平变化情况及其预测价值。结果：病例组QRS、QTc水平显著高于对照组,QT、LVEF水平显著低于对照组,差异显著（P＜0.05）;轻度QRS、QTc显著低于中度、重度患者,QT、LVEF水平显著高于中度、重度患者;中度患者QRS、QTc显著低于重度患者,QT、LVEF水平显著高于重度患者,差异显著（P＜0.05）;ROC结果显示,QRS预测心源性猝死的AUC为0.989,灵敏度△为84.59%,特异度为87.68%,截断值为115.59ms;QT预测心源性猝死的AUC为0.944,灵敏度85.12%,特异度为88.45%,截断值为21.69ms;QTc预测心源性猝死的AUC为0.984,灵敏度为86.05%,特异度为88.61%,截断值为416.39ms,LVEF预测心源性猝死的AUC为0.997,灵敏度87.15%,特异度为89.05%,截断值为45.63%,（P＜0.05）。结论：QRS、QT、QTc及LVEF在心源性猝死患者中检查,可显著提高心源性猝死临床诊断效能。     

电磁脉冲诱导大鼠心肌闰盘Cx43连接蛋白的上调

目的:探讨电磁脉冲(EMP)对SD大鼠心肌闰盘及主要连接蛋白Cx43的影响.方法:将雄性SD大鼠35只,随机分为对照组和EMP辐照组,EMP辐照组又分为照后即刻、1h、3h、6h、12h、24h组,每组5只大鼠.应用EMP模拟发生器对EMP辐照组大鼠进行辐照,场强为200 kV/m、前沿15 ns、脉宽7-8 ns、脉冲次数200次,脉冲间隔为7s,麻醉后取大鼠左心室,采用硝酸镧示踪法和透射电子显微镜观察大鼠心肌闰盘(ID)结构的变化,用Real-Time PCR方法和Western blot方法检测EMP辐照后,大鼠连接蛋白Cx43在转录水平和蛋白水平表达量的变化情况.结果:电镜下正常对照组大鼠心肌ID处未见硝酸镧颗粒沉积;EMP组大鼠ID处可见硝酸镧颗粒,且随时间的延长,硝酸镧颗粒沉积量逐渐增多,以照后6h组硝酸镧颗粒沉积量达最大,然后硝酸镧颗粒沉积量随时间延长逐渐减少,24h组恢复正常.心肌细胞Cx43的mRNA表达水平在EMP照后lh和6h明显增高,分别是对照组的1.95、3.10倍(P＜0.05);照后即刻、3h、12h、24h表达水平与对照组相比差异无统计学意义(P＞0.05).Western blot结果为照后即刻、1h、3h和6h组大鼠心肌细胞Cx43蛋白表达量与对照组比较显著增加,12h、24h与对照组相比差异无统计学意义(P＞0.05).结论:EMP可使心肌闰盘结构发生改变,上调Cx43蛋白的mRNA水平和蛋白表达量.     

蛋白质芯片技术检测脑损伤大鼠血清差异蛋白

目的:研究大鼠脑损伤后血清中蛋白质表达谱的变化及其特点.方法:采用弱阳离子交换芯片(WCX2)结合表面增强激光解析电离飞行时间质谱技术分析大鼠闭合性脑损伤后4 h、8 h、12 h、24 h、48 h血清中蛋白质表达谱的改变.结果:与对照组相比,脑损伤后血清中有2个蛋白质的表达谱发生改变.其中差异蛋白5648Da,在4 h、8 h和12 h组表达降低(P＜0.01),24 h和48 h组表达恢复;差异蛋白9681Da在对照组、24 h和48 h组几乎不表达,而4 h、8 h和12 h组表达增加(P＜0.05).结论:脑损伤可引起血清中蛋白质表达谱发生变化.     

The conduction system and expressions of hyperpolarization-activated cyclic nucleotide-gated cation channel 4 and connexin43 expressions in the hearts of fetal day 13 mice

We investigated the development of the sinus node of the heart conduction system by localizing hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) and connexin43 (Cx43) in the hearts of fetal day 13 mice. Horizontal serial sections of day 13 whole fetuses were stained by hematoxylin and eosin and immunofluorescence to identify myocardial cells that express HCN4, hyperpolarization-activated cyclic nucleotide-gated cation channel 2 (HCN2) and Cx43. Expression levels of HCN4 and Cx43 were determined by quantitative RT-PCR in both fetal day 13 and adult mice. We found that both Cx43 and HCN4 expressions were located on the cell membranes in the hearts of fetal day 13 mice, but Cx43 was distributed throughout the myocardial cells. HCN4 expression was concentrated mainly in the left dorsal epicardium of the right atrium where Cx43 expression was low or absent. Quantitative RT-PCR demonstrated that HCN4 expression was significantly higher and HCN2 expression was significantly lower in fetal day 13 mice than in adults. We found no statistically significant difference in Cx43 expression between fetal day 13 mice and adults. HCN4 stained myocardial cells in the left dorsal epicardium of the right atrium are the origin of the sinus node and the remainder of the heart conduction system.     

Overexpression of cardiac connexin45 increases susceptibility to ventricular tachyarrhythmias in vivo

Electrophysiological remodeling involving gap junctions has been demonstrated in failing hearts and may contribute to intercellular uncoupling, delayed conduction, enhanced arrhythmias, and vulnerability to sudden death in patients with heart failure. Recently, we showed that failing human hearts exhibit marked increases in connexin45 (Cx45) expression in addition to previously documented decreases in connexin43 (Cx43) expression. Each of these changes results in reduced gap junction coupling. The objective of the present study was to examine functional consequences of increased Cx45 in cardiac gap junctions. Transgenic mice with cardiac-selective overexpression of the developmentally downregulated cardiac connexin, connexin45 (Cx45OE mice) were subjected to in vivo electrophysiology studies in which an intracardiac catheter was used to induce ventricular arrhythmias in anesthetized mice, and in which ambulatory ECG monitoring was used to detect spontaneous arrhythmias in unanesthetized mice. Hearts were analyzed by TaqMan RT-PCR, immunostaining, immunoblotting, and echocardiography. Lucifer yellow and neurobiotin dye transfer was used to assess coupling in transgenic and control myocyte cultures. Cx45 mRNA was two orders of magnitude greater in Cx45OE mice. Cx45-immunoreactive signal at gap junctions increased twofold and total Cx45 protein by immunoblotting increased 25% in Cx45OE mice compared with nontransgenic littermate controls. Functionally, Cx45OE mice exhibited more inducible ventricular tachycardia than controls but did not exhibit any other functional or structural derangements as assessed by echocardiography. Ventricular myocytes isolated from Cx45OE mice exhibited diminished intercellular transfer of Lucifer yellow dye and increased transfer of neurobiotin, consistent with altered cell-to-cell communication. Thus increased myocardial expression of Cx45 results in remodeling of intercellular coupling and greater susceptibility to ventricular arrhythmias in vivo.     

西格列汀对糖尿病小鼠心肌重构和自噬的影响及其机制

目的: 探讨西格列汀对糖尿病小鼠心肌重构和自噬的影响和可能的机制。方法: 10周龄的C57小鼠腹腔注射STZ 50 mg/(kg·d),连续注射5 d,7 d测血糖浓度＞16.7 mmol/L视为糖尿病小鼠造模成功,造模成功4周后给与药物干预。本实验分四组,对照组(control, 腹腔注射等体积的缓冲液, n=10)、模型组(Streptozocin, STZ腹腔注射诱导糖尿病模型,n=8)、处理组(在模型组基础上给与西格列汀灌胃10 mg/(kg·d),n=8)、抑制剂组(在处理组的基础上给与腹腔注射Compound C (AMPK通路抑制剂,10 mg/(kg·d),n=8),对照组腹腔注射等体积缓冲液,6周后称体重,处死,取小鼠心脏并分离心室称重,计算心室/体重比,HE染色观察心肌细胞形态,Masson染色观察纤维化程度,Western blot 检测心肌脑钠肽(BNP)、转化生长因子β(TGF-β)、缝隙连接蛋白43(Cx43)、AMP依赖的蛋白激酶(AMPK)、LC3B蛋白表达。结果: 给药6周后,与对照组相比,模型组小鼠体重没有明显改变,心室/体重比明显增加(P＜0.05),苏木素-伊红(HE)染色显示细胞增大,Masson染色显示心肌间隙纤维化增多,BNP、TGF-β蛋白明显升高,Cx43、LC3B、AMPK蛋白下降(P＜0.05)。与模型组相比,西格列汀组BNP、TGF-β蛋白明显下降,Cx43、LC3B、AMPK蛋白增多(P＜0.05)。然而Compound C会抑制Cx43、LC3B、AMPK蛋白表达的上调(P＜ 0.05)。结论: 西格列汀可以改善糖尿病小鼠心肌肥厚和纤维化,并且可以通过AMPK相关通路调节Cx43和自噬。     

心脏性猝死者心肌HO-1和VEGF的表达及意义

目的：探讨血红素加氧酶-1（heme oxygenase-1,HO-1）、血管内皮生长因子（vascular endothelial growth factor,VEGF）在心脏性猝死病人心室肌细胞中的表达及其意义。方法：运用免疫组织化学方法和Simple PCI图像分析系统观察33例心脏性猝死组和18例非心脏性猝死对照组尸检心肌组织中HO-1、VEGF蛋白的表达情况。结果：心脏性猝死组心肌组织HO-1（155.090±8.957）和VEGF蛋白表达（121.020±10.927）均显著高于非心脏性猝死对照组（116.200±6.355、84.207±4.402,均p〈0.05）。结论：HO-1和VEGF蛋白在心脏性猝死者心肌组织表达增强,可能与心脏性猝死有一定关系。     

压力-应激对大鼠心肌细胞Cx43蛋白表达及心肌纤维化的影响

目的:探讨压力-应激对大鼠心肌细胞间隙连接蛋白-43(Cx43)蛋白表达及心肌纤维化的影响。方法:将20只雄性SD大鼠随机分为正常对照组(n=10)和模型组(n=10),对照组正常饲养,模型组给予不可预测性复合应激结合孤养建立压力-应激大鼠模型。监测两组大鼠的体重变化,并通过组织形态学方法,探讨压力-应激对大鼠心肌细胞Cx43蛋白表达及心肌纤维化的影响。结果:在为期42天的造模过程中,从应激第7天开始,模型组大鼠体重明显低于对照组,差异有统计学意义(P<0.001)。且模型组体重增长缓慢,体重增长百分比明显低于对照组,差异有统计学意义(P<0.001)。与对照组相比,模型组大鼠组织HE染色可见心肌细胞排列紊乱,横纹消失,细胞间隙增大,部分肌纤维断裂、溶解,Masson染色可见心肌间质纤维化,胶原纤维增生、排列紊乱。心肌细胞免疫组化染色可见模型组Cx43蛋白表达明显下降(平均光密度值为0.0110±0.0028),与对照组相比(平均光密度值为0.0268±0.0025),差异具有统计学意义(t=-13.081,P<0.001)。结论:过度疲劳导致猝死的发生可能与Cx43蛋白表达水平的下降引起的恶性心律失常有关。     

心可舒治疗频发早搏疗效观察

目的:应用心率变异性的方法观察心可舒片对早搏的治疗效果及其影响。方法:将96例频发早搏患者随机分成治疗组(51例)和对照组(45例)。对照组给予倍他乐克缓释片口服,47.5mg/次,1次/日,治疗组在口服倍他乐克缓释片基础上加用心可舒片4片/次,3次/日。在服药前及服药后1个月各行1次动态心电图及普通心电图检查,并进行临床观察。结果:治疗组在消除早搏,改善临床症状方面较对照组明显有效(P<0.05),治疗组较对照组心率变异性改善有明显差异(P<0.05)。结论:心可舒片与倍他乐克合用可有效增加其治疗早搏的作用,同时改善心率变异性和改善倍他乐克引起的窦性心动过缓副作用,有较好的临床疗效。     

Functional characterization of a trafficking-defective HCN4 mutation, D553N, associated with cardiac arrhythmia

Hyperpolarization-activated cyclic nucleotide-gated channel 4 gene HCN4 is a pacemaker channel that plays a key role in automaticity of sinus node in the heart, and an HCN4 mutation was reported in a patient with sinus node dysfunction. Expression of HCN4 in the heart is, however, not confined to the sinus node cells but is found in other tissues, including cells of the conduction system. On the other hand, mutations in another cardiac ion channel gene, SCN5A, also cause sinus node dysfunction as well as other cardiac arrhythmias, including long QT syndrome, Brugada syndrome, idiopathic ventricular fibrillation, and progressive cardiac conduction disturbance. These observations imply that HCN4 abnormalities may be involved in the pathogenesis of various arrhythmias, similar to the SCN5A mutations. In this study, we analyzed patients suffering from sinus node dysfunction, progressive cardiac conduction disease, and idiopathic ventricular fibrillation for mutations in HCN4. A missense mutation, D553N, was found in a patient with sinus node dysfunction who showed recurrent syncope, QT prolongation in electrocardiogram, and polymorphic ventricular tachycardia, torsade de pointes. In vitro functional study of the D553N mutation showed a reduced membranous expression associated with decreased If currents because of a trafficking defect of the HCN4 channel in a dominant-negative manner. These data suggest that the loss of function of HCN4 is associated with sinus nodal dysfunction and that a consequence of pacemaker channel abnormality might underlie clinical features of QT prolongation and polymorphic ventricular tachycardia developed under certain conditions.     

Sudden Death in Hospital after Discharge from Coronary Care Unit

In a group of 339 patients with acute myocardial infarction treated in a coronary care unit, 273 left the unit while improving and were expected to leave hospital alive; 23 had a cardiac arrest or died suddenly while still in hospital—17 died immediately or after temporary resuscitation and six were resuscitated to leave hospital alive. Ventricular fibrillation was found in 13 of the 20 patients attended by the cardiac arrest team. The incidents were scattered from the 4th to the 24th day after the onset of infarction. Risk factors in these “late sudden death” patients were compared with the 250 patients who left the unit while improving and did not die or suffer cardiac arrest. The patients susceptible to late sudden death were characterized early in their hospital course by the findings of severe, predominantly anterior infarction, left ventricular failure, persistent sinus tachycardia, and frequent ventricular arrhythmias. It is suggested that such patients be chosen for prolonged observation in a second-stage coronary care unit.