ACCELERATION OF WIDESPREAD ADENOVIRAL GENE-TRANSFER TO INTACT RABBIT HEARTS BY CORONARY PERFUSION WITH LOW-CALCIUM AND SEROTONIN

Previous attempts at adenoviral gene transfer to the intact heart have been limited by the requirement for prolonged exposure io high virus concentrations. fn an ex vivo coronary perfusion model of intact adult rabbit hearts, we previously reported gene transfer to 96% of cardiac myocytes after a 60 min exposure to 1.6 x 10(9) p.f.u./ml Ad beta gal , a recombinant adenovirus encoding beta-galactosidase. Here we sought to decrease the virus exposure lime by enhancing microvascular permea bility to increase the efficiency of adenoviral gene transfer. Baselin e perfusion with 1.0x 10(8) p.f.u./ml Ad beta gal in normal Krebs solu tion (I mM calcium) caused infection of 22% of myocytes at 30 min and 40% at 60 and 120 min. increasing the virus concentration, decreasing perfusate calcium concentration, or pretreating with serotonin or brad ykinin in Krebs solution or I-NAME in heparinized rabbit blood signifi cantly decreased Vie necessary exposure time. Under optimal conditions of serotonin pretreatment, 50 mu mol/l perfusate ate calcium, and a v irus concentration of 1.6 x 10(9) p.f.u./ml, 2 min of coronary perfusi on sufficed to produce near-total infection, This profound enhancement of infection parameters has important implications for in vivo myocar dial gene transfer, where a similar strategy could facilitate gene the rapy for common myocardial disorders.