心肌干细胞移植可短期内改善心肌梗死心电生理稳定性和提高室颤阈值

背景：课题组前期研究已证实心肌干细胞移植中期(6周)能有效改善心肌梗死大鼠的心电生理稳定性和室颤阈值。目的：比较心肌干细胞和骨髓间充质干细胞移植对心肌梗死大鼠心电生理学稳定性和室颤阈值的短期疗效差异。方法：取30只健康雄性SD大鼠,开胸结扎大鼠的左前降支冠状动脉建立心肌梗死动物实验模型,随机分成3组,分别为心肌干细胞移植组,骨髓间充质干细胞移植组,PBS对照组,每组10只。分别于建模成功2周后在梗死区心肌内局部注射0.1 mL PBS悬浮的5×10⁶ PKH26标记的心肌干细胞、0.1 mL PBS悬浮的5×10⁶ PKH26标记的骨髓间充质干细胞及0.1 mL PBS。植入2周后,再次开胸检测大鼠心脏梗死区、梗死边缘区、非梗死区的心电生理特性和室颤阈值。实验结束后,分离心脏梗死边缘区进行病理切片及荧光显微镜检查PHK26标记的心肌干细胞和骨髓间充质干细胞缝隙连接蛋白43表达情况。结果与结论：心肌干细胞移植组单极电图纠正的激动恢复时间离散度、电刺激所激发的恶性心律失常及梗死区、梗死边缘区、非梗死区的室颤阈值与PBS组、骨髓间充质干细胞移植组相比差异有显著性意义(P < 0.05);骨髓间充质干细胞移植组单极电图纠正的激动恢复时间离散度及非梗死区的室颤阈值与PBS组相比差异有显著性意义。病理结果提示在心肌干细胞组、骨髓间充质干细胞组梗死边缘区发现有心肌干细胞、骨髓间充质干细胞的存在。通过组织免疫荧光检测,PKH26标记的心肌干细胞表达较多的缝隙连接蛋白43,而PKH26标记的骨髓间充质干细胞很少表达缝隙连接蛋白43,PBS组不表达缝隙连接蛋白43。上述结果提示心肌干细胞移植短期内心电生理学特性改善的效应较骨髓间充质干细胞优越,且改善效应与缝隙连接蛋白43相关。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

心肌干细胞移植可改进心力衰竭大鼠室颤阈值和电生理的稳定性

背景：心肌干细胞移植后是否引起或加重心肌梗死患者的心律失常是治疗的关键问题。 目的：观察心肌干细胞对心力衰竭大鼠室颤阈值和电生理稳定性的影响。 方法：开胸结扎20只SD大鼠左前降支冠状动脉,2周后选取其中的10只局部梗死心肌内注射PKH26荧光标记的由PBS悬浮的心肌干细胞,另10只局部梗死心肌内注射等量PBS。治疗6周后,再次开胸检测梗死边缘区的心电生理特性和室颤阈值。实验结束后,摘取心脏行病理切片,检查PHK26标记的心肌干细胞是否在梗死区内生存并表达连接蛋白43及α-肌动蛋白。 结果与结论：与对照组相比,心肌干细胞移植组单极电图激动恢复时间及纠正的激动恢复时间明显缩短,电刺激所激发的恶性心律失常明显减少,室颤阈值明显提高。PHK26标记的心肌干细胞在梗死边缘区内被发现并表达连接蛋白43和α-肌动蛋白。提示心肌干细胞移植能改善心力衰竭大鼠心电生理的稳定性和提高室颤阈值;心肌干细胞可在体内表达心肌细胞和连接蛋白的标记。     

心肌干细胞调控ANG Ⅱ/AT1R/TGF-β1/SMAD/CX43通路改进心电生理学稳定性和室颤阈值

BACKGROUND:Previous studies have demonstrated that the electrophysiological stability and ventricular fibrillation threshold after myocardial infarction in rats are significantly improved in the mid-term of cardiac stem cell transplantation, but relative regulatory mechanism and pathway remain unclear. OBJECTIVE:To explore the relative molecular regulatory mechanism of cardiac stem cells improving the electrophysiological stability and ventricular fibrillation threshold after myocardial infarction in rats.  METHODS:Myocardial infarction was induced in 20 Sprague-Dawley rats by ligation of the left anterior descending coronary, which were then randomized into two groups (n=10 per group) and were subjected to the injection of cardiac stem cells labeled with PKH26 in phosphate buffer solution (cardiac stem cell group) or the same amount of phosphate buffer solution (PBS) alone (PBS group) into the local infarct zone at 2 weeks after modeling, respectively. Six weeks later, relevant signaling molecules involved in the ANGII/AT1R/TGF-β1/SMAD/Cx43 pathway were all examined in myocardial tissues of the left ventricle and harvested blood samples. RESULTS AND CONCLUSION:Compared with the PBS group, expressions of connexin 43 in different zones of the left ventricle were significantly increased in the cardiac stem cell group (P < 0.01); there was a significant reduction of the angiotensin II level in plasma and different regions of the left ventricular (P < 0.05; P < 0.01). Furthermore, in the cardiac stem cell group, expressions of angiotensin II type I receptor, transforming growth factor-β1, SMAD2 and SMAD3 were significantly decreased (P < 0.01). Whereas SMAD7 was significantly elevated (P < 0.05) in different areas of the left ventricle compared with the phosphate buffer solution group. These findings suggest that the cardiac stem cell transplantation can improve the electrophysiological stability and ventricular fibrillation threshold after myocardial infarction by enhancing the expression of connexin 43 via ANGII/AT1R/TGF-beta1/SMAD/CX43 signaling pathway.     

糖原合成酶激酶3β过表达心肌干细胞移植治疗心肌梗死

BACKGROUND:The mechanism and effect of glycogen synthase kinase 3β (GSK-3β) in the differentiation of cardiac stem cells into cardiomyocytes are still unclear, although GSK-3β is closely related to the life activities of cells. OBJECTIVE:To investigate the changes of GSK-3β expression in the treatment of myocardial infarction in rats undergoing cardiac stem cell transplantation. METHODS:The isolation and culture of cardiac stem cells were performed in 10 neonatal rats. Lentivirus overexpressing GSK-3β or LacZ (control) was constructed and transferred into cardiac stem cells. Animal model of myocardial infarction was made in 30 Sprague-Dawley rats. Six weeks after model preparation, rat models were assigned into GSK-3β, LacZ or PBS group. GSK-3β or LacZ overexpressing cardiac stem cell solution or PBS in equal volume was injected into the rat myocardium, respectively. Four weeks after transplantation, the cardiac function and myocardial collagen production in rats were detected and compared. RESULTS AND CONCLUSION:Compared with the other two groups, the left ventricular ejection fraction was significantly higher, and the left ventricular end diastolic diameter was significantly lower in the GSK-3β group (P < 0.05). Hydroxyproline content, type I collagen mRNA, and type III collagen mRNA expression were significantly lower in the GSK-3β group than the other two groups (P < 0.05). Findings from Masson staining showed that the content of blue-stained collagen was significantly lower in the GSK-3β group than the LacZ group. Moreover, lowest myocardial infarction size was found in the GSK-3β group (P < 0.05). All these experimental findings show that GSK-3 overexpression plays a positive role in promoting the therapeutic effect of cardiac stem cell transplantation.     

胚胎干细胞移植治疗急性心肌梗死后心肌病理形态学及血流动力学变化

目的：探讨胚胎干细胞(ESC)移植治疗急性心肌梗死(AMI)后心肌组织形态学及血液动力学变化。 方法： Wistar大鼠40只随机分为正常对照组、梗死未治疗组(梗死组)、梗死中心移植组(中心组)、梗死周边移植组(周边组)共4组。结扎冠状动脉左前降支制成心肌梗死模型，梗死后1周移植体外分化并经标记的ESCs，移植后4周分别检测组织形态及血流动力学指标的改变。 结果： 移植后4周，周边组移植细胞稳定存活，而中心组移植细胞未能存活。心功能及组织学检测表明中心组与梗死组无显著差异(P＞0.05)；与梗死组比较，周边组梗死面积显著小于梗死组(P＜0.01)，(21.0±1.3)% vs (40.7±2.2)%；左室重量小于梗死组(P＜0.01)，(702.0±24.0)mg vs (882.2±32.6)mg；反映左室收缩功能的指标+dp/dtmax和LVSP均大于梗死组(P＜0.01)，分别为 (7.9±0.7)×103mmHg/s vs (5.9±0.5)×103 mmHg/s和(117.5±10.7) mmHg vs (89.2±8.1) mmHg；而LVEDP均明显小于梗死组(P＜0.01)，(8.5±0.3)mmHg vs (13.6±1.2)mmHg。 结论： 急性心肌梗死后于梗死周边区移植ESCs可以阻止心室重构、减少瘢痕面积、改善心功能。     

脐血干细胞经冠状动脉移植可降低心律失常评分及室性心律失常发生率

BACKGROUND:Until now, it is still unclear whether the stem cell transplantation triggers adverse effects on the myocardial electrical activity, resulting in the emergence of arrhythmia. OBJECTIVE:To explore the effect of intracoronary transplantation of umbilical cord blood stem cells on arrhythmia score and incidence of ventricular arrhythmia. METHODS:According to therapeutic strategies, 73 patients with coronary heart disease were assigned to receive drug therapy in control group (n=38) and umbilical cord blood stem cell transplantation in observation group (n=35). Arrhythmia score, incidence of ventricular arrhythmia and adverse reactions were recorded and analyzed before and 1, 4, 8 weeks after transplantation. RESULTS AND CONCLUSION:After treatment, arrhythmia scores were significantly reduced in the two groups, especially in the observation group, to exhibit a continuous decline trend (P < 0.05). Compared with the control group, the incidence of ventricular arrhythmia was significantly lower in the observation (P < 0.05). However, there were no significant changes in the blood pressure, heart rate and blood oxygen saturation before and after transplantation, and no acute heart failure and death occurred in the two groups. These results suggest that the intracoronary transplantation of umbilical cord blood stem cells exhibits superiorities in the treatment of coronary artery disease, significantly reducing the arrhythmia score, reducing the incidence of ventricular arrhythmia, and resulting in less adverse reactions.     

吡格列酮联合骨髓间充质干细胞移植治疗改善大鼠心肌梗死后的心功能

背景：前期研究发现骨髓间充质干细胞移植能够改善心肌梗死大鼠的心功能,但整体效果并不太理想。 目的：拟采用PPAR-γ激动剂吡格列酮联合骨髓间充质干细胞移植治疗以进一步改善心肌梗死大鼠的心功能并探讨相关机制。 方法：开胸结扎20只SD大鼠左前降支冠状动脉并随机分为2组：骨髓间充质干细胞组和骨髓间充质干细胞+吡格列酮组。2周后在局部梗死心肌内注射PKH26标记的由PBS悬浮的骨髓间充质干细胞,联合治疗组在注射骨髓间充质干细胞后予以吡格列酮3 mg/(kg•d)连续灌胃2周。细胞移植后2周进行超声心动图检测,免疫荧光染色、Western blot、qRT-PCR检测左心室心肌组织不同区域PPAR-γ、TGF-β1/SMAD通路相关因子和Cx43的表达情况。 结果与结论：两组大鼠基础心功能参数无明显差异性。细胞移植2周后,骨髓间充质干细胞+吡格列酮组左室舒张末径、左室收缩末径明显减小,左室射血分数明显增高;左心室心肌组织不同区域PPAR-γ和Cx43的表达量显著增加;TGF-β1、SMAD2、SMAD3在梗死区和梗死边缘区表达明显下降。以上结果提示PPAR-γ激动剂吡格列酮干预能够增强骨髓间充质干细胞移植对心功能的改善作用,其机制可能与PPAR-γ抑制TGF-β1/SMAD通路进而提高Cx43的表达有关。  中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

经静脉心肌超声造影对心肌梗死患者自体骨髓单个核细胞移植后心肌微循环的评价

目的利用经静脉心肌超声造影（IMCE）观察心肌梗死患者自体骨髓单个核细胞移植术前后心肌微循环的变化。方法40例急性心肌梗死患者在病情稳定后7～10d,行延迟经皮冠状动脉成形术（PCI）。随机分成骨髓细胞移植组（20例）和对照组（20例）,观察术前、术后1月、术后6月左心室舒张末内径（LVDd）,左室射血分数（LVEF）和术前及术后1个月的IMCE,测量平台期的心肌显像增大强度A,曲线上升平均斜率β及A与β之积在手术前后的变化。结果移植组LVEF由术前的（37.26±4.21）1月后上升到（54.42±5.26）（P〈0.05）;而对照组差异不显著（38.86±4.63对40.28±4.56）（P〉0.05）。LVDd移植组术后6月与术前比较差异不显著（50.23±3.42对52.48±3.26）（P〉0.05）;而对照组（50.96±2.68对64.31±3.28）（P〈0.05）心脏有扩大趋势。IMCE示手术后相关心肌节段的A、β及A.β均较术前显著增加。其中A.β（dB/s）移植组由术前的2.37±0.16（dB/s）增加到术后的15.60±0.24（dB/s）;较对照组（2.06±0.12至7.98±0.23）增加更为明显（P〈0.05）,示急性心肌梗死延迟PCI术后梗死相关节段心肌血流灌注速度和灌注量均有增加,自体骨髓单个核细胞移植组增加更明显。结论自体骨髓单个核细胞移植可改善梗死区心肌微循环,明显增加心肌血流量。     

左西孟旦对大鼠急性心肌梗死后心肌纤维化及心功能的影响

目的 探讨左西孟旦对心肌梗死（myocardial infarction,MI）大鼠心肌纤维化的影响及其作用机制。 方法 通过结扎大鼠左冠状动脉前降支建立MI模型。30只存活的MI大鼠随机分为模型组和左西孟旦组（Levo组）,每组15只。假手术组（n=10）的大鼠接受相同的外科手术,只是不进行动脉结扎。Levo组胃灌注左西孟旦4.67 μg·kg-1·d-1治疗28 d。假手术组和模型组大鼠同时给等量蒸馏水。采用二维超声心动图评价心功能,Masson-trichrome评价心肌纤维化程度,RT-qPCR检测COL1A1、COL3A1基因表达,Western blot检测SIRT1/TGF-β1/Smad3信号通路蛋白表达。 结果 超声心动图测量显示,与模型组相比,Levo组大鼠的左室收缩末期内径降低（P<0.05）,而射血分数和缩短分数显著升高（P<0.01）。Masson-trichrome显示,左西孟旦治疗可显著减少坏死心肌组织、抑制炎性细胞的浸润并减少胶原蛋白沉积。RT-qPCR分析显示,左西孟旦治疗显著降低了MI大鼠心肌组织中Ⅰ型和Ⅲ型胶原的含量（P<0.01）。Western blot检测显示,左西孟旦治疗可显著上调MI大鼠心肌组织中SIRT1蛋白表达（P<0.01）,下调TGF-β1和p-Smad3蛋白表达（P<0.01）。 结论 左西孟旦具有抗纤维化和心保护作用。这些作用可能通过SIRT1/TGF-β1/Smad3信号通路介导。     

静脉及心肌注射骨髓间充质基质细胞未能改善慢性心肌梗死大鼠的心脏功能

背景：有多项研究证明,经静脉或经心肌表面注射移植间充质基质细胞促进了急性心肌梗死后心功能的改善。然而,目前尚缺乏有关经静脉联合经心肌注射移植间充质基质细胞对慢性心肌梗死心脏功能影响的研究。 目的：探讨静脉联合心肌注射骨髓间充质基质细胞对慢性心肌梗死模型大鼠心脏功能的影响及其机制。 方法：体外培养扩增Lewis大鼠的骨髓间充质基质细胞。将3×10⁶ BrdU标记过的骨髓间充质基质细胞分别经股静脉和经心肌表面注射移植于慢性心肌梗死模型大鼠,对照组注射等量PBS。4周后检测两组大鼠心功能的变化,并对大鼠心脏组织行免疫组化染色,观察细胞分化情况及毛细血管数量。 结果与结论：骨髓间充质基质细胞移植4周后,细胞移植组与对照组心功能无明显差别,免疫组化染色提示存留于心肌组织内的移植细胞未分化为心肌细胞,心梗瘢痕区血管密度在细胞移植组和对照组间没有明显差别。结果表明经静脉联合经心肌注射骨髓间充质基质细胞未能改善慢性心肌梗死模型大鼠的心脏功能。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

同种异体骨髓间充质干细胞移植在心肌梗死后心室重建中的作用

BACKGROUND:Myocardial infarction leads to ischemic changes in the myocardium, triggering the emergence of ventricular remodeling, which is an important cause of death. Myocardial infarction is a common disease in the middle-aged and elderly population, but autologous bone marrow mesenchymal stem cells from these patients exhibit a weak ability of proliferation and differentiation. Therefore, a positive attempt of allogeneic stem cell transplantation is required in order to obtain better therapeutic outcomes. OBJECTIVE:To explore the effect of allogeneic bone marrow mesenchymal stem cells on ventricular remodeling after myocardial infarction.   METHODS:Bone marrow mesenchymal stem cells from 10 neonatal rats and 10 adult rats were isolated, cultured and identified. Another 40 rats were randomly assigned into four groups (n=10/group): model group, neonatal rat cell transplantation group, adult rat cell transplantation group, or sham group. Animal models of myocardial infarction were made in rats in the all groups except for the sham group in which the rats were given sham operation. Rats in the two cell transplantation groups were given the corresponding cell transplantation. Four weeks postoperatively, heart function of rats was detected in each group, and cardiac tissues were taken to detect changes in collagen formation and blood vessel density in the infarct area. RESULTS AND CONCLUSION:Four weeks after surgery, rats in the model group showed significant changes in cardiac function indexes as compared with the other groups (P < 0.05), while compared with the model group, these cardiac function indexes improved in both two cell transplantation groups, but there was no significant difference between the two cell transplantation groups (P > 0.05). Meanwhile, compared with the model group, significantly decreased collagen formation and increased blood vessel density were found in both two cell transplantation groups (P < 0.05). Additionally, the vascular density of the infarct area was highest in the sham group (P < 0.05). Experimental results show that both neonatal and adult rat bone marrow mesenchymal stem cell transplantation can improve cardiac function of rats, reduce the formation of collagen in the infarct area and delay ventricular remodeling after myocardial infarction.     

Sensitization by low temperature of the isolated perfused heart to induced ventricular fibrillation

Summary The ventricular fibrillation threshold (VFT) in the perfused isolated heart of rabbits and cats was compared at 37° C and during hypothermia (17° to 34° C). The method consisted in measuring the minimal current of a single square-wave 10 msec pulse which was required to induce fibrillation or tachycardia when applied to the left ventricle during the vulnerable period of late systole.Hypothermia significantly lowered the VFT in both species and reduced the incidence of induced persistent (>60 sec) fibrillation or tachycardia in rabbit hearts so that only a non-persistent arrhythmia could be induced in a high proportion of trials. The vulnerable time (VT), i. e. the minimal delay after the R wave of the e. c. g. at which the single current pulse had to be applied to induce the arrhythmia, was lengthened by the hypothermia; the duration of electrical systole was lengthened to a similar extent as indicated by the unaltered VT:R-T ratio. The total refractory period in rabbit hearts was prolonged more than the duration of electrical systole by cold.The results in this study indicate that in ventricular fibrillation one should attempt to differentiate those factors which initiate the arrhythmia from those which are concerned in its maintenance.     

HeartSaver: a mobile cardiac monitoring system for auto-detection of atrial fibrillation, myocardial infarction, and atrio-ventricular block

A mobile medical device, dubbed HeartSaver, is developed for real-time monitoring of a patient's electrocardiogram (ECG) and automatic detection of several cardiac pathologies, including atrial fibrillation, myocardial infarction and atrio-ventricular block. HeartSaver is based on adroit integration of four different modern technologies: electronics, wireless communication, computer, and information technologies in the service of medicine. The physical device consists of four modules: sensor and ECG processing unit, a microcontroller, a link between the microcontroller and the cell phone, and mobile software associated with the system. HeartSaver includes automated cardiac pathology detection algorithms. These algorithms are simple enough to be implemented on a low-cost, limited-power microcontroller but powerful enough to detect the relevant cardiac pathologies. When an abnormality is detected, the microcontroller sends a signal to a cell phone. This operation triggers an application software on the cell phone that sends a text message transmitting information about patient's physiological condition and location promptly to a physician or a guardian. HeartSaver can be used by millions of cardiac patients with the potential to transform the cardiac diagnosis, care, and treatment and save thousands of lives.     

长期TCV116干预对心肌梗死后心室重塑及心功能的影响

目的:研究长期新型血管紧张素Ⅱ1型受体阻断剂TCV116干预对心肌梗死(MI)后心肌重塑及心功能的影响。方法:通过结扎冠状动脉左前降支复制大鼠MI模型,1周后将大鼠随机分为:(1)MI对照组;(2)MITCV116治疗组(2mg.kg^-1·d^-1):另设假手术组及假手术TCV116组。22周后检测:(1)血流动力学参数如平均动脉压(MAP)、左室收缩压(LVSP)、室内压最大上升和下降速率(dp／dt_max)和左室舒张末压(LVEDP)及心脏形态学指标如左室相对重量(LVW／BW)和左室腔相对面积(LVCA／BW);(2)室间隔存活心肌中β肌球蛋白重链(βMHC)、B型钠尿肽(BNP)、转化生长因子β₁(TGF-β₁)、I型和III型胶原(collagenI、III)基因的mRNA表达;(3)存活率。结果:MI对照组与MITCV116治疗组间总体MI范围无显著差异(34%±14％vs33%±13%,P>0.05)。MI对照组LVW／BW和LVCA／BW显著高于假手术组(P<0.01),βMHC、BNP、TGF-β₁、collagenI和III基因的mRAN表达显著大于假手术组(P<0.01);同时MAP、LVSP、dp／dt_max显著低于和LVEDP显著高于假手术组(P<0.01),也伴随着生存时间显著缩短(P<0.05)。TCV116治疗组,LVW／BW和LVCA／BW与MI对照组比无显著差异,βMHC、BNP、TGF-β₁、collagenI和III基因的mRNA表达低于MI对照组(P<0.05或P<0.01);与此同时,MAP、LVSP、dp／dt_max显著高于及LVEDP显著低于MI对照组(P<0.05或P<0.01),并伴随着生存时间的延长(P<0.05)。结论:长期血管紧张素II1型受体阻断剂干预能显著改善心肌梗死后大鼠心室重塑及心功能。     

The effect of bioengineered acellular collagen patch on cardiac remodeling and ventricular function post myocardial infarction

Regeneration of the damaged myocardium is one of the most challenging fronts in the field of tissue engineering due to the limited capacity of adult heart tissue to heal and to the mechanical and structural constraints of the cardiac tissue. In this study we demonstrate that an engineered acellular scaffold comprising type I collagen, endowed with specific physiomechanical properties, improves cardiac function when used as a cardiac patch following myocardial infarction. Patches were grafted onto the infarcted myocardium in adult murine hearts immediately after ligation of left anterior descending artery and the physiological outcomes were monitored by echocardiography, and by hemodynamic and histological analyses four weeks post infarction. In comparison to infarcted hearts with no treatment, hearts bearing patches preserved contractility and significantly protected the cardiac tissue from injury at the anatomical and functional levels. This improvement was accompanied by attenuated left ventricular remodeling, diminished fibrosis, and formation of a network of interconnected blood vessels within the infarct. Histological and immunostaining confirmed integration of the patch with native cardiac cells including fibroblasts, smooth muscle cells, epicardial cells, and immature cardiomyocytes. In summary, an acellular biomaterial with specific biomechanical properties promotes the endogenous capacity of the infarcted myocardium to attenuate remodeling and improve heart function following myocardial infarction.