Optical Imaging of Cardiac Reporter Gene Expression in Living Rats

J. C. Wu
2002 Circulation  
Background-Studies of cardiac gene transfer rely on postmortem analysis using histologic staining or enzyme assays. Noninvasive imaging of the temporal and spatial characteristics of cardiac gene expression in the same subject offers significant advantages. Methods and Results-Rats underwent direct myocardial injection via left thoracotomy with adenovirus-expressing firefly luciferase (Ad-CMV-Fluc; nϭ30). The reporter substrate D-luciferin was injected intraperitoneally. Serial images were
more » ... al images were acquired by use of a cooled charged couple detector (CCD) camera. Results are expressed as relative light unit per minute (RLU/min). Rats transduced with 1ϫ10 9 plaque-forming units show decremental cardiac luciferase activity over time: 152 070Ϯ21 170 (day 2), 195 806Ϯ62 630 (day 5), 7250Ϯ2941 (day 8), and 2040Ϯ971 RLU/min (day 14). To assess the detection sensitivity, serially diluted titers of Ad-CMV-Fluc were injected: 1ϫ10 9 (195 393Ϯ14 896), 1ϫ10 8 (33 777Ϯ18 179), 1ϫ10 7 (417Ϯ91), 1ϫ10 6 (185Ϯ64), 1ϫ10 5 (53Ϯ1), and control (54Ϯ1) (PϽ0.05 for 1ϫ10 9 , 1ϫ10 8 , and 1ϫ10 7 plaque-forming units versus control adenovirus-expressing mutant thymidine kinase [Ad-CMV-HSV1-sr39tk]; nϭ3). Finally, rats were euthanized, and in vitro luciferase activity correlated with in vivo CCD signals (r 2 ϭ0.92). Conclusions-This study demonstrates for the first time the feasibility of imaging the location, magnitude, and time course of cardiac reporter gene expression in living rats. Cardiac gene therapy studies could be aided with wider application of this approach. (Circulation. 2002;105:1631-1634.)
doi:10.1161/01.cir.0000014984.95520.ad pmid:11940538 fatcat:awuznntfnzgdxacd4xoqqlbeuu