慢频率依赖性心律失常发生机制及稳心颗粒作用机理研究

发布时间：2018-06-17 01:22

本文选题：慢频率依赖性长QT综合症 + 尖端扭转性室速　；参考：《北京协和医学院》2017年博士论文

【摘要】：背景慢频率依赖性长QT综合症并非由于服用某种药物引起,该类患者通常以出现心室率突然减慢,QTc间期伴随性延长,发作尖端扭转性室速或室颤为特点。抢救时植入临时起搏器并快速起搏可以缩短QTc间期并终止恶性心律失常发生。既往研究显示,慢频率依赖性长QT综合症多由于钾通道(IKs or IKr)功能减弱引起,但其分子机制仍不完全明了。目的本研究对5例慢频率依赖性长QT综合症患者进行相关基因突变位点分析,并且从细胞水平评估SCN5A基因突变对钠通道功能的影响,揭示慢频率依赖性长QT综合症的发病机理。方法收集5例慢频率依赖性长QT综合症患者的临床资料及心电图信息。经同意后抽取患者及其家属的外周静脉血,对相关基因进行突变位点筛查。构建SCN5A突变体质粒,并与野生型SCN5A分别转染进入人胚胎肾293(HEK-293)细胞。使用全细胞膜片钳技术观察并比较两组转染细胞的钠通道电生理特性。结果分析临床资料显示,患者年龄范围在52±22岁,其中4名女性。所有患者均在心率减慢时发作室颤或尖端扭转性室速,其中4名患有房室传导阻滞,1名患有窦性心动过缓。经过植入起搏器或者带起搏功能的除颤器后,该心律失常得到抑制。大于70次的快速起搏使QTc间期由583±60ms缩短至470±37ms。我们对5例患者进行了心肌病及心律失常相关基因(包括 KCNQ1,KCNH2,SCN5A,ANK2,KCNE1,KCNE2,CAV3 等)的检测,发现了 10 个杂合突变基因,分别是 SCN5A(p.S705F)、HCN4(p.R666Q)、Titin(p.R12053W、p.T16515M、p.R4770Q、p.A1868T、p.R1 8427C、p.I9550M,)、DMD(p.E440K)和 SGCD(p.Q283R)。通过对SCN5AS705F基因突变进行全细胞膜片钳功能分析,结果显示:与野生型钠通道(-241±54 pA/pF,n=7)相比,突变型(-247±90 pA/pF,n=11)并未影响钠电流密度峰值(P0.05),但是突变型钠通道的稳态激活曲线出现左移(V1/2mutatio VS.V1/2WT,-43.10±1.49 mV vs.-34.97±3.11mV,P0.05;Kmutation vs.KwT,4.86±0.49mV vs.6.97±1.40mV,P0.05),野生型钠通道功能增强。在刺激频率分别为2Hz,1Hz,0.5Hz时,突变型钠通道0.5Hz起搏刺激与2Hz相比,INa/peak ratio升高了 6.8%。然而野生型钠通道在3种起搏频率下,INa/peak ratio保持不变。提示慢频率时突变通道SCN5AS705F功能增强。结论慢频率依赖性长QT综合症可能与多种基因变异相关。而突变型钠通道慢频率依赖性功能增强可以部分解释该病为何在心率突然减慢时出现恶性心律失常。钠通道基因突变是慢频率依赖性长QT综合症的致病原因之一。背景急性心肌梗死发病率逐年增高,而心肌梗死后发生心室重构是造成梗死后心力衰竭的重要原因,虽然早期灌注治疗开通了犯罪血管,拯救了许多人的生命,但其对心梗后心功能的影响仍未可知。研究显示,心室重构是心肌梗死后心脏的一种修复行为,重构的发生与心肌梗死范围、梗死后炎症反应、神经体液调节等紧密相关。因此,如何能够减少梗死细胞范围,逆转心室重构,减慢心衰进程成了人们共同关注的问题。众所周知,稳心颗粒是用来治疗心律失常的一种复合中药制剂,其对心肌梗死后心衰的作用仍值得探索。目的国内外关于中药稳心颗粒分子层面的研究成果报道较少,本研究致力于探索兔心梗模型经稳心颗粒治疗后的基因表达谱改变和病理改变。方法将二十只成年雄性兔随机分成4组:sham,model,WXKL和captopril。其中,model、WXKL和captopril需在全麻下通过结扎前降支建立心梗模型,sham只开胸不结扎。随后WXKL和captopril分别口服喂养稳心颗粒817mg/kg/d和卡托普利8mg/kg/d,其它两组喂等量纯水。四周后,在全麻下做完心脏彩超后,开胸取心脏进行基因表达谱芯片和病理研究(HE,Masson and Tunel)。结果稳心颗粒可以下调炎症相关基因(CX3CR1,MRC1,and FPR1),凋亡相关基因(CathepsinCandTTC5),肾素-血管紧张素系统相关基因(ACEandEDN1),同时可以上调血管生成调节基因RSP03。病理结果显示相比于模型组,稳心颗粒组心功能更好,病理损伤更轻,凋亡细胞更少。病理结果与表达谱芯片结果相符。结论本研究结果显示稳心颗粒可以有效减轻心梗后心肌损伤、炎症和凋亡,有效抑制肾素-血管紧张素系统,在减轻心梗后心衰方面具有一定的治疗意义。
[Abstract]:Background slow frequency dependent long QT syndrome is not caused by taking a certain drug. The patients usually are characterized by sudden ventricular rate slowing, QTc interphase concomitant prolonged, torsional ventricular tachycardia or ventricular fibrillation. The temporary pacemaker implantation and rapid pacing can shorten the QTc interval and terminate the malignant arrhythmia. The study shows that the slow frequency dependent long QT syndrome is due to the weakening of the function of the potassium channel (IKs or IKr), but its molecular mechanism is still not fully understood. The purpose of this study was to analyze the gene mutation sites in 5 patients with slow frequency dependent long QT syndrome and to evaluate the effect of the SCN5A gene mutation on the sodium channel function from the cell level. The pathogenesis of slow frequency dependent long QT syndrome was revealed. Methods the clinical data and electrocardiogram information of 5 patients with slow frequency dependent long QT syndrome were collected. After consent, the peripheral venous blood of the patients and their families was selected and the mutation sites were screened for the related genes. The SCN5A mutant body particles were constructed and transferred to the wild type SCN5A respectively. A total cell patch clamp technique was used to observe and compare the electrophysiological characteristics of the sodium channel of the two transfected cells using the whole cell patch clamp technique. The results of clinical data showed that the age range of the patients was 52 + 22 years old, including 4 women. All patients had ventricular fibrillation or torsional ventricular tachycardia at the time of heart rate slowing, and 4 of them had room. Ventricular conduction block, 1 patients with sinus bradycardia. After implantation of pacemaker or pacing function defibrillator, the arrhythmia was suppressed. More than 70 times of rapid pacing shortened the QTc interval from 583 + 60ms to 470 37ms., we performed cardiomyopathy and arrhythmia related genes in 5 patients (including KCNQ1, KCNH2, SCN5A, ANK2, KCNE). 1, KCNE2, CAV3 and so on, 10 heterozygous mutations were found, SCN5A (p.S705F), HCN4 (p.R666Q), Titin (p.R12053W, p.T16515M, p.R4770Q, p.A1868T, p.R1), and the whole cell patch clamp function analysis of the gene mutation showed that: with the wild type sodium channel (-241 + 54 pA/pF, n=7), the mutant type (-247 + 90 pA/pF, n=11) did not affect the peak value of sodium current density (P0.05), but the steady-state activation curve of the mutant sodium channel appeared left shift (V1/2mutatio VS.V1/2WT, -43.10 + 1.49 mV vs.-34.97), and the function of the wild type sodium channel increased. When the stimulation frequency was 2Hz, 1Hz, and 0.5Hz, the mutation type sodium channel 0.5Hz pacing stimulation compared with 2Hz, INa/peak ratio increased 6.8%., but the wild type sodium channel remained unchanged at the 3 pacing frequencies, suggesting that the SCN5AS705F function of the mutant channel was stronger when the slow frequency was at the slow frequency. Conclusion the slow frequency dependent long QT syndrome may be more than that of the slow frequency dependent long QT syndrome. The slow frequency dependent function of the mutant sodium channel can partly explain why the disease appears to be malignant arrhythmia when the heart rate is suddenly slowed. The sodium channel gene mutation is one of the causes of the slow frequency dependent long QT syndrome. Ventricular remodeling is an important cause of post infarction heart failure. Although early perfusion therapy opened a criminal vessel and saved many people's life, its effect on cardiac function after myocardial infarction is still unknown. The study showed that ventricular remodeling is a kind of repair behavior after myocardial infarction, the occurrence of reconstruction and the range of myocardial infarction, infarction The post inflammatory response and neurohumoral regulation are closely related. Therefore, how to reduce the range of infarct cells, reverse ventricular remodeling and slow down the process of heart failure have become a common concern. It is well known that Wenxin granule is a compound traditional Chinese medicine for the treatment of arrhythmia, and its effect on heart failure after myocardial infarction is still worth exploring. Objective in order to explore the changes and pathological changes of gene expression spectrum of rabbit myocardial infarction model after the treatment of Wenxin granule, twenty adult male rabbits were randomly divided into 4 groups: sham, model, WXKL and captopril., and model, WXKL and captopril need to be in the whole. The myocardial infarction model was established by the anterior descending branch of ligation. Sham only opened the chest without ligation. Then WXKL and captopril were fed on the heart granule 817mg/kg/d and Kato Pury 8mg/kg/d respectively. The other two groups were fed the same amount of pure water. After four weeks, the heart was performed by the heart color Doppler ultrasound and the HE, Masson and (HE, Masson and). Tunel). Results the results showed that Wenxin Granule could reduce inflammation related genes (CX3CR1, MRC1, and FPR1), apoptosis related gene (CathepsinCandTTC5), renin angiotensin system related gene (ACEandEDN1), and up regulate the pathological results of vasculogenic regulation gene RSP03., compared with the model group. The heart function of the group was better than that of the model group, and the pathological damage was better. More light, fewer apoptotic cells. Pathological results coincide with the results of the expression spectrum chip. Conclusion the results of this study show that Wenxin granule can effectively reduce myocardial injury after myocardial infarction, inflammation and apoptosis, effectively inhibit the renin angiotensin system, and have certain therapeutic significance in reducing heart failure after myocardial infarction.
【学位授予单位】：北京协和医学院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R541.7

【相似文献】