Gene delivery using ultrasound contrast agents

With the human genome product and continuing advances in molecular biology many therapeutic genes have been discovered. In the cardiovascular system, gene therapy has the potential to improve myocardial vascularization and am eliorate congestive heart failure. For successful development of clinical g ene therapy, however, effective gene delivery vectors are needed. Ultrasoun d contrast agents can be used to develop new, more effective vectors for ge ne delivery. Ultrasound contrast agents lower the threshold for cavitation by ultrasound energy. Using physical properties of microbubbles and coating materials, genetic drugs have been incorporated into ultrasound contrast a gents. Gene-bearing microbubbles can be injected IV and ultrasound energy a pplied to the target region. As the microbubbles enter the region of insona tion, the microbubbles cavitate, locally releasing DNA. Cavitation also lik ely causes a local shockwave that improves cellular uptake of DNA. With tra nsthoracic ultrasound using commercially available diagnostic ultrasound sy stem and an IV injection of gene-bearing microbubbles, high levels of trans gene expression are observed in the insonated region of the myocardium. Thi s new technology using microbubbles and ultrasound for gene delivery merits further study and development.