All solid organ allografts are maintained for some period of time outside of the body. While unwelcome ischemic injury results from this ex vivo phase, it does offer a unique window for focused and efficient gene transfer that could improve graft and recipient survival. Delayed graft function and primary nonfunction remain recalcitrant problems in transplantation and have been associated with late graft failure due to chronic rejection. Ischemia/reperfusion injury (IRI) is an important antigen-independent factor that can contribute to the pathogenesis of these clinical entities. We have developed a chimeric expression vector that generates abundant antisense/ribozyme regulatory molecules in situ and has proven efficacy. The goal of this work is to establish the conditions for the selective inactivation of individual genes responsible for IRI through the efficient ex vivo delivery of our chimeric transgene into allografts. The adhesion molecule ICAM-1 has been chosen as a model target gene to develop this gene therapy strategy because there is compelling evidence that it is an important trigger molecule for cascades of proinflamatory mediators responsible for IRI. Our hypothesis is that the ex vivo delivery of a chimeric transgene designed to produce anti- ICAM-1 regulatory molecules will inhibit the expression of ICAM-I in endothelial cells and abrogate or ameliorate IRI in an ischemic organ. Using a rational approach to designing chimeric constructs and testing them in vitro, we hope to establish the requirements and conditions for inhibition of ICAM-1 and other important molecules in the IRI pathway in transplanted allografts. Both viral and nonviral approaches to delivering effective ICAM-1 inhibitory transgenes will be developed for use in a rat renal IRI model. Because this method of inhibition is based on technology that is more potent and specific than strategies previously employed, it possess great potential as both a powerful therapeutic agent and a surrogate genetic tool for interrogating gene function. This work has important implications for the selective inactivation of gene function in allografts through ex vivo gene transfer.
| King, Karen E; Warren, Daniel S; Samaniego-Picota, Milagros et al. (2004) Antibody, complement and accommodation in ABO-incompatible transplants. Curr Opin Immunol 16:545-9 |
| Sonnenday, Christopher J; Warren, Daniel S; Cooke, Sara K et al. (2004) A novel chimeric ribozyme vector produces potent inhibition of ICAM-1 expression on ischemic vascular endothelium. J Gene Med 6:1394-402 |
