β-Galactosidase staining following intracoronary infusion of cationic liposomes in the in vivo rabbit heart is produced by microinfarction rather than effective gene transfer: a cautionary tale

Abstract

The myocardium is a potential target for the expression of conversion at day 3 with associated myocardial damage. exogenous genes to treat inherited and acquired diseases.We hypothesised that the damage was associated with Although adenovirus-mediated gene transfer has resulted macro-aggregates of cationic liposomes-DNA occluding in high-level gene transfer in vivo via direct intramyocardial the microcirculation. When such aggregates were excluded injection and via a percutaneous intra-arterial route, the no X-gal conversion was seen in vivo. In order to show time-course of gene expression is limited by host immune that X-gal conversion occurs in areas of infarction in the responses. It was the aim of this study to test whether catmyocardium we caused closed chest infarction by ionic liposome-mediated gene transfer, which does not sufdeploying a platinum micro-embolisation coil in the circumfer from the aforementioned problems, was feasible in the flex coronary artery. At day 3 X-gal conversion was adult rabbit myocardium via a percutaneous transluminal observed in the territory supplied by the occluded artery. approach. Doses of plasmid DNA encoding lacZ from 200-Thus, microinfarction causes the false positive appearance 800 g complexed to cationic liposomes resulted in X-gal of gene transfer when using a lacZ reporter gene.

Advantages of Catheter-Based Adenoviral Delivery of Genes to the Heart for Studies of Cardiac Disease

“…X-Gal staining for LacZ gene transfer revealed significant and heterogeneously expression throughout both the sham and banded hearts 48-72 hrs following Ad.cmv.LacZ delivery, similar to the level of overexpression illustrated in figure 4. Importantly, there were no "false positives" for endogenous LacZ expression in hearts as a consequence of microinfarctions formed during the intracoronary infusion as previously speculated by Wright et al (Wright et al, 1998).…”

Myocardial gene transfer by selective pressure-regulated retroinfusion of coronary veins

“…Gene Therapy detection of efficient adenoviral gene transfer using both reporter genes argues against false positive ␤-galactosidase staining due to microinfarctions. 20 Furthermore, there was no evidence for microinfarctions in these probes by histological assessment.…”

In vivo myocardial gene transfer: optimization and evaluation of intracoronary gene delivery in vivo

“…8 We previously demonstrated that interpretation of results when using the LacZ reporter is complicated by potential artefacts that may in part explain this discrepancy. 9 by oxygenated perfluorocarbon emulsion as viral diluent Further understanding of the factors involved in gene transfer by intracoronary delivery of recombinant adenovirus has been gained through a series of experiments involving Langendorff perfusion. 10,11 These studies show that the coronary flow rate, absolute amount of virus, time spent in the coronary circulation and composition of perfusate were major factors affecting intracoronary gene transfer 10 and increasing capillary permeability leads to improvements in gene transfer efficiency.…”