Prentice H, Kloner R A, Li Y, Newman L, Kedes L
Department of Biochemistry & Molecular Biology, University of Southern California School of Medicine, Los Angeles, USA.
J Mol Cell Cardiol. 1996 Jan;28(1):133-40. doi: 10.1006/jmcc.1996.0013.
A non-contracting scar following myocardial infarction can adversely affect ventricular topography and hemodynamic function. Gene transfer has the potential to prevent or alter such pathophysiological processes. Normal myocardium is a proven target for delivery of DNA or viral vectors but the potential for gene therapy in ischemic myocardium has not been evaluated. In an initial series of experiments, we determined whether the direct injection of reporter genes into hearts subjected to coronary artery occlusion followed by reperfusion could result in gene expression comparable to the levels observed in non-occluded normal hearts. Anesthetized rats were subjected to 15 min or 60 min of proximal coronary occlusion or sham operation. Luciferase gene under the control of the Rous sarcoma virus promoter was injected directly into the anterior left wall. At 1 week, high expression of luciferase was observed in both the ischemic/reperfused and non-ischemic tissue. Thus DNA transfer by direct injection is possible after ischemic injury and uptake and expression are not impaired. In a second series of experiments, myocardial infarcts in dogs were injected with a beta-galactosidase expressing retroviral vector. LNPOZ. Six to 11 days later frozen sections revealed macroscopically visible expression of beta-galactosidase activity. Not only can foreign genes be taken up by direct injection of DNA or retroviruses into ischemic/reperfused myocardium but they can be transcribed and the protein synthetic machinery of the injured cells can produce recombinant polypeptides that retain enzymatic activity. These results open the way for the investigation of gene therapy in models of ischemia.
心肌梗死后形成的无收缩瘢痕会对心室形态和血流动力学功能产生不利影响。基因转移有可能预防或改变此类病理生理过程。正常心肌是已被证实的DNA或病毒载体递送靶点，但缺血心肌的基因治疗潜力尚未得到评估。在最初的一系列实验中，我们确定将报告基因直接注射到经历冠状动脉闭塞再灌注的心脏中，是否能产生与未闭塞正常心脏中观察到的水平相当的基因表达。对麻醉的大鼠进行15分钟或60分钟的冠状动脉近端闭塞或假手术。将受劳氏肉瘤病毒启动子控制的荧光素酶基因直接注射到左前壁。1周时，在缺血/再灌注组织和非缺血组织中均观察到荧光素酶的高表达。因此，缺血损伤后通过直接注射进行DNA转移是可行的，摄取和表达均未受损。在第二系列实验中，给犬心肌梗死灶注射表达β-半乳糖苷酶的逆转录病毒载体LNPOZ。6至11天后，冰冻切片显示宏观可见的β-半乳糖苷酶活性表达。不仅通过将DNA或逆转录病毒直接注射到缺血/再灌注心肌中可以摄取外源基因，而且它们可以被转录，受损细胞的蛋白质合成机制可以产生保留酶活性的重组多肽。这些结果为在缺血模型中研究基因治疗开辟了道路。
