Ex vivo machine perfusion as a platform for lentiviral gene delivery in rat livers

Developing new strategies for local monitoring and delivery of immunosuppression is critical to making allografts safer and more accessible. Ex vivo genetic modification of grafts using machine perfusion presents a promising approach to improve graft function and modulate immune responses while minimizing risks of off-target effects and systemic immunogenicity in vivo. This proof-of-concept study demonstrates the feasibility of using normothermic machine perfusion (NMP) to mimic in vitro conditions for effective gene delivery. In this study, lentiviral vectors encoding the secreted biomarker Gaussia Luciferase (GLuc) and red fluorescent protein (RFP) were introduced ex vivo to rodent livers during a 72-h machine perfusion protocol. After an initial 24-h exposure to viral vectors, the organs were maintained in perfusion for an additional 48 h to monitor gene expression, aligning with in vitro benchmarks. Control livers were perfused in similar fashion, but without viral injections. Virally perfused livers exhibited nearly a 10-fold increase in luminescence compared to controls (p < 0.0001), indicating successful genetic modification of the organs. These findings validate the use of machine perfusion systems and viral vectors to genetically engineer whole organs ex vivo, laying the groundwork for a broad range of applications in transplantation through genetic manipulation of organ systems. Future studies will focus on refining this technology to enhance precision in gene expression and explore its implications for clinical translation.