【作者】 张昌伟；

【导师】 胡盛寿；

【作者基本信息】 北京协和医学院 ， 心血管外科学， 2011， 博士

【摘要】 目的：组织工程心肌为心肌梗死的治疗提供了新的途径,由于缺乏足够的血供,现有的方法无法构建出具有足够体积和生物学功能的心肌组织而应用于临床。本研究的主要目的是探讨自体心房组织以及大网膜联合移植对慢性心肌梗死大鼠心脏功能以及心律失常的影响。方法：通过前降支结扎法建立大鼠心肌梗死模型。3周后将筛选合格的模型动物随机分为4组：对照组(Con group),仅再次开胸；心房移植组(A group),开胸后裁取左心耳组织移植于心肌梗死及周边区；大网膜移植组(O group)经膈肌将大网膜移植于心肌梗死及周边区；联合移植组(OA group)分别移植左心耳组织和大网膜。手术4周后,超声心动图评价心室重构和心脏功能,Masson染色检测心肌梗死面积和疤痕厚度,免疫组化评价心耳存活、血管化,蛋白免疫印迹法检测血管内皮生长因子(VEGF)、金属蛋白酶(MMP-2/MMP-9)及其抑制物(TIMP-3)蛋白表达,明胶酶谱法评价金属蛋白酶活性,酶联免疫吸附法检测内皮素-1(ET-1)蛋白水平,程序性电刺激评价心律失常易感性(Arrhythmia Score).结果：4周后,仅在OA组观察到左心耳组织部分存活。Masson染色显示各组心肌梗死面积无显著差异(P>0.05),OA组疤痕厚度显著增厚(391±31μm vs 329±33μm,P<0.05)；超声心动图结果证实OA组心脏功能显著改善(LVEF:57.9±5.8% vs 47.5±4.5%,P<0.05 and LVFS:25.2±3.6% vs 20.7±2.0%,P<0.05)；免疫组织化学结果显示A组以及OA组梗死周边区血管密度明显增加(49/0.2mm2 vs 33/0.2mm2,P 0.01 and 48/0.2mm2 vs 33/0.2mm2,P<0.01蛋白免疫印迹显示MMP-2/MMP-9在OA组表达下降,TIMP-3表达无显著差异,VEGF在O组以及OA组表达增加；明胶酶谱法证实OA组金属蛋白酶活性下降(MMP-2:68%P=0.002 and MMP-9:64%P=0.016),；酶联免疫吸附法证实ET-1蛋白水平在O组以及OA组显著下调(4.69±0.47 pg/mg vs 5.95±0.55 pg/mg,P<0.01 and 4.79±0.57 pg/mg vs 5.95±0.55 pg/mg；P<0.05)；程序性电刺激显示单纯大网膜以及联合移植大鼠心律失常易感性显著下降(0.46±0.31vs2.10±0.60,P<0.05 and 0.50±0.34 vs 2.10±0.60,P<0.05)结论：大网膜能通过再血管化使移植的心房组织部分存活,联合移植的方法能通过降低室壁应力、改善胶原重构和增加血供等途径改善慢性心肌梗死大鼠心脏功能,大网膜移植能有效的降低慢性心肌梗死大鼠心律失常易感性。目的：心脏神经重构是心肌梗死后心律失常的重要发病机制,研究组前期的动物实验提示大网膜以及大网膜联合移植降低了慢性心肌梗死大鼠心律失常的易感性,本研究将证实大网膜移植是否通过逆转心脏神经重构降低心律失常易感性。方法：Sprague-Dawley大鼠随机分为3组：假手术组(Sham group,n=20),第一次开胸穿线不结扎,3周后仅再次开胸；单纯心肌梗死组(MI group,n=20),第一次通过前降支结扎法建立心肌梗死模型,3周后仅再次开胸,不移植大网膜；大网膜移植组(MI+O group,n=20),第一次通过前降支结扎法建立心肌梗死模型,3周后再次开胸并移植大网膜。4周后分别采用电生理方法评价各组大鼠的电生理特性,免疫组织化学方法检测心脏神经分布及密度,蛋白免疫印迹检测连接蛋白43(Connexin43)、礻神经生长因了(NGF)的表达,酶联免疫吸附法检测心肌组织内皮素-1(ET-1)的表达。结果：与MI组相比,MI+O组大鼠心律失常易感性显著下降(评分：0.9±0.2 vs 3.5±1.2,p<0.05),电传导阻滞得到显著改善(自发电位：3.4±0.3mv vs 1.5±0.2mv,p<0.05；同步阂值：2.2±0.2mv vs 5.5±0.3mv,p<0.05)；免疫组织化学显示大网膜移植显著降低了心肌梗死周边区新生神经以及交感神经密度(GAP43:768.6±144.1μm2/mm2vs 1388.4±244.9μm2/mm2,p<0.05；TH:1018.5.±124.7μm2/mm2vs 1552.4±270.3μm2/mm2,p<0.05):蛋白免疫印迹结果表明MI+O组NGF表达下调而Connexin43的表达上调,酶联免疫吸附法显示MI+O组ET-1的表达下调(4.5±0.3pg/mg vs 5.8±0.4 pg/mg,p<0.05)结论：心肌梗死后在其周边区存在以交感神经过度再生的重构现象,大网膜移植能显著逆转心肌梗死后的心脏神经重构,并降低低慢性心肌梗死大鼠心律失常易感性。目的：术前风险评估模型对临床医生以及卫生行政部门都具有重要的指导意义,本课题组前期研究证实目前的“金标准”欧洲心脏手术风险评估模型(EuroSCORE)显著高估我国冠状动脉旁路移植术的死亡率,因此根据中国心脏外科数据库构建了适合我国国情的中国冠心病手术风险评估模型(SinoSCORE)。本研究旨在验证SinoSCORE对阜外医院单中心单纯非体外循环冠状动脉旁路移植手术的预测价值。方法：自2004年1月至2008年12月,共1966例患者在阜外医院行单纯非体外循环冠状动脉旁路移植术,收集这些患者的人口学资料、术前危险因素、术中危险因素、住院死亡率、术后并发症等信息,根据SinoSCORE和EuroSCORE评分法则分别评分,终点事件定义为住院死亡。采用应用接受者工作特征曲线(ROC)下面积(AUC)衡量模型的区分度,采用单因素logistic回归及Hosmer-Lemeshow (HL)卡方检验考察模型的校准度。结果：患者平均年龄为61.6±9.3岁,其中80.5%为男性患者。住院死亡22例,总体死亡率为1.1%。EuroSCORE预测住院死亡率为2.9±2.2%,SinoSCORE则为1.6±3.7%。SinoSCORE和EuroSCORE的AUC分别为0.76(95%置信区间,0.66-0.87,P<0.01)和0.68(95%置信区间,0.52-0.84,P<0.05)；HL卡方检验P值分别为0.78和0.76。结论：该单中心数据证实,SinoSCORE比EuroSCORE能更准确的预测非体外循环冠状动脉旁路移植术的住院死亡率。SinoSCORE为我国非体外循环冠状动脉旁路移植术的术前风险评估和分层提供了一种较客观准确的手段。更多还原

【Abstract】 Objectives:Regional application of tissue engineered cardiac patch can alleviate ventricular remodeling and improve functional recovery in experimental models of ischemia. However, the size of the engineered patch is limited due to the insufficient vascularization. The present study evaluated the effects of autologous atrial tissue patch cardiomyoplasty and/or omentopexy in rat models of myocardial infarction (MI).Methods:Myocardial infarction was induced by left coronary artery ligation in Sprague-Dawley rats. The qualified animals would be allocated randomizedly to four groups three weeks post operatively. The animals in control group only received re-thoracotomy. The autologous atrial tissue patch was harvested from the left atrial appendage along its long axis and was transplanted to the infracted zone in autologous atrial tissue patch cardiomyoplasty group. The omentum was transplanted to the same zone through the diaphragm. In the combined group, these two procedures were completed. The echocardiogram (UCG) was used to evaluate the cardiac remodeling and heart function. The infracted size and scar thickness were assessed by histological study. The angiogenesis and survival of the transplanted atrial tissue were estimated by the immunohistochemistry. Western blot was employed to evaluate the expression of VEGF, MMPs and TIMP3. The activities of MMPs were identified by gelatin zymography. Programmed electrical stimulation was utilized to assess the susceptibility of arrhythmia.Results:After 4 weeks, surviving myocardium was only visualized in the OA group as indicated by immunolabeling cardiac troponin-I. Histological study showed that the infracted size did not decreased in any treatment group while the scar thickness was increased in OA group compared with Con group (391±31μm vs 329±33μm, P＜0.05). Only the animals in OA group showed improved heart function assessed by LVEF (57.9±5.8%vs 47.5±4.5%, P<0.05) and LVFS (25.2±3.6%vs 20.7±2.0%, P＜0.05). The immunohistochemistry study demonstrated the angiogenesis was improved in the group O and OA (49/0.2mm2 vs 33/0.2mm2, P< 0.01 and 48/0.2mm2 vs 33/0.2mm2, P< 0.01) companied by increased expression of VEGF by western blot. Western blot revealed the expression of MMPs decreased significantly in the OA group while the TIMP3 did not change. The activities of MMP2 and MMP9 were decreased by 68% and 64% respectively by gelatin zymography. The ELISA showed the endothelin-1 level in group O and OA decreased significantly (4.69±0.47 pg/mg vs 5.95±0.55 pg/mg, P<0.01 and 4.79±0.57 pg/mg vs 5.95±0.55 pg/mg; P<0.05). The programmed electrical stimulation demonstrated the arrhythmia score in group O and OA decreased significantly (0.46±0.31vs2.10±0.60, P＜0.05 and 0.50±0.34 vs 2.10±0.60, P<0.05).Conclusions:The omentopexy supported the survival of transplanted autologous atrial tissue patch, which resulted in attenuated ventricular remodeling and restoration of heart function in rats with experimental MI. In addition, the omentopexy and combined surgery could decrease the susceptibility of arrhythmia. Our findings might represent a novel therapeutic strategy for heart failure after myocardial infarction. Objectives:The cardiac nerve remodeling plays a key role in the ventricular arrhythmia after myocardial infarction. Our previous research has indicated that the omentopexy could decrease the susceptibility of the ventricular arrhythmia in rats with chronic myocardial infarction. This study aimed to test the hypothesis that this benefit effect is partly attributed to the attenuation of the cardiac nerve remodeling.Methods:The Sprague-Dawley rats were allocated randomizedly to three groups:the sham group without myocardial infarction or omentopexy; the isolated myocardial infarction group without omentopexy and the omentopexy group. Four weeks after the operation, the electrophysiological characteristics were assessed by the electrophysiological techniques. The new and sympathetic nerves in the border zone were analyzed by immunohistochemistry. The expressions of NGF and Connexin43 were manifestated by western blot. The ELISA was utilized to evaluate the expression of the ET-1 of the cardiac tissue.Results:After four weeks, the arrhythmia score of the rats in omentopexy group was significantly less than those in isolated myocardial infarction group(0.9±0.2 vs 3.5±1.2, p<0.05). Meanwhile, the electrical transduction improved significantly in the omentopexy group compared with isolated myocardial infarction group (spontaneous signal ampti tude:3.4±0.3mv vs 1.5±0.2mv,p<0.05; capture threshold:2.2±0.2mv vs 5.5±0.3mv,p<0.05). The immunihistochemisty staining by GAP43 and TH showed that densities of the new and sympathetic nerves decreased remarkably in the omentopexy group (GAP43:768.6±144.1μm2/mm2 vs 1388.4±244.9μm2/mm2, p<0.05; TH:1018.5.±124.7μm2/mm2 vs 1552.4±270.3μm2/mm2, p<0.05). The western blot showed that the expression level of NGF was down-regulated while that of Connexin43 was up-regulated. The ELISA study demonstrated the expression of ET-1 decreased significantly (4.5±0.3pg/mg vs 5.8±0.4 pg/mg,p<0.05).Conclusions:The omentopexy could decrease the susceptibility of ventricular arrhythmia after myocardial infarction by attenuation of the cardiac nerve remodeling. The ET-1-NGF pathway may play a key role in this beneficial effect. Objectives:The risk evaluation model possesses great importance for the cardiac surgeons and the administrative department of health. Our previous research has convinced that the European System of Cardiac Operative Risk Evaluation (EuroSCORE) overestimated the risk of Chinese patients with coronary artery bypass grafting(CABG) and we constructed the Sino System of Coronary Operative Risk Evaluation (SinoSCORE) based on the data from Chinese Coronary Artery Bypass Grafting Registry. This study aimed to compare the predictive values of SinoSCORE and EuroSCORE in the patients undergone isolated off-pump coronary artery bypass grafting (OPCAB) in Fuwai hospital.Method:The clinical data of 1966 consecutive patients undergone isolated OPCAB in Fuwai hospital between Jan.2004 and Dec.2008 was retrospectively collected. The endpoint event was defined as the in-hospital mortality. The score values of all patients were calculated according to the SinoSCORE and EuroSCORE additive model respectively. The areas under the receiver operator curves (ROC) were computed to evaluate the two models’discriminatory ability in predicting in-hospital mortality. The univariate logistic regression and Hosmer-Lemeshow (HL) chi-square test was utilized to assess the calibration of the two models.Results:The mean age of all patients was 61.6±9.3 years and 80.5% were male. Mean SinoSCORE and EuroSCORE of the 1966 patients were 1.6±3.7 and 2.9±2.2 with an observed mortality of 1.1%. The areas under the ROC curves for SinoSCORE and EuroSCORE were 0.76 (95%CI 0.66 to 0.87,P<0.01) and 0.68 (95%CI 0.52 to 0.84,.P<0.05). P values of the HL chi-square test were 0.80 and 0.63, respectively.Conclusions:The present single center study demonstrated that the SinoSCORE is superior to EuroSCORE in predicting the in-hospital mortality in patients undergoing isolated OPCAB. SinoSCORE is an accurate and objective risk stratification model for Chinese OPCAB patients.更多还原