Naked DNA delivery to whole pig cardiac tissue by coronary sinus retrograde injection employing non-invasive catheterization.

BACKGROUND

Hydrodynamic injection has demonstrated to be very efficient in the liver of small animals, although this procedure must be translated to the clinical practice in a milder but no less efficient way. The present study evaluates the capacity of non-invasive interventional catheterization as a procedure for naked DNA delivery to the heart in large animals.

METHODS

Two catheters were placed in the coronary sinus: one of them to block blood circulation and the other to retrogradely inject 50 ml of a saline solution of DNA (20 µg/ml) containing the enhanced green fluorescent protein (EGFP) gene, at a flow rate of 5 ml/s.

RESULTS

The results obtained show that EGFP protein, identified by immunohistochemistry, was present and widely distributed throughout the atrial and ventricular cardiac tissue. This observation agrees with the efficiency of EGFP gene delivery resulting in 1-200 EGFP gene copies per endogenous haploid genome. However, the transcription efficiency of the exogenous EGFP gene was at a ratio of 0.2-10 copies with respect to the endogenous GAPDH gene, suggesting that optimized gene constructs for expression in cardiac tissue could increase the final efficacy of gene transfer.

CONCLUSIONS

We conclude that the retrovenous injection of naked DNA in the coronary sinus employing the catheterization technique is an easy and probably safe method for whole cardiac gene transfer.