Bekeredjian Raffi, Chen Shuyuan, Frenkel Peter A, Grayburn Paul A, Shohet Ralph V
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75390-8573, USA.
Circulation. 2003 Aug 26;108(8):1022-6. doi: 10.1161/01.CIR.0000084535.35435.AE. Epub 2003 Aug 11.
Noninvasive, tissue-specific delivery of therapeutic agents would be a valuable clinical tool. We have previously shown that ultrasound-targeted microbubble destruction can direct expression of an adenoviral reporter to the heart. The present study shows that this method can be applied to selectively deliver plasmid vectors to the heart.
We used albumin and lipid microbubbles containing plasmids with a luciferase transgene to target the heart in rats. After 4 days, organs were harvested and analyzed for reporter gene expression. In a second set of experiments, the hearts of rats treated with plasmids were harvested at various time points during a 4-week period. Both luciferase activity and mRNA concentrations were measured. Luciferase transfection with plasmids showed highly specific gene expression in the heart, with hardly any activity in control organs. Time course evaluation showed high transgene expression in the first 4 days, with a rapid decline thereafter. Repeated treatment produced a second peak of transgene expression with similar decay.
Ultrasound-mediated destruction of microbubbles directs plasmid transgene expression to the heart with much greater specificity than viral vectors and can be regulated by repeated treatments. This noninvasive technique is a promising method for cardiac gene therapy.
治疗药物的非侵入性、组织特异性递送将是一种有价值的临床工具。我们之前已经表明，超声靶向微泡破坏可将腺病毒报告基因的表达导向心脏。本研究表明，该方法可用于将质粒载体选择性递送至心脏。
我们使用含有荧光素酶转基因质粒的白蛋白和脂质微泡靶向大鼠心脏。4天后，收获器官并分析报告基因表达。在第二组实验中，在4周期间的不同时间点收获用质粒处理的大鼠心脏。同时测量荧光素酶活性和mRNA浓度。用质粒进行的荧光素酶转染在心脏中显示出高度特异性的基因表达，而对照器官中几乎没有活性。时间进程评估显示，在最初4天转基因表达较高，此后迅速下降。重复治疗产生了具有相似衰减的第二个转基因表达峰值。
超声介导的微泡破坏将质粒转基因表达导向心脏，其特异性远高于病毒载体，并且可以通过重复治疗进行调节。这种非侵入性技术是一种有前景的心脏基因治疗方法。
