Gene Delivery Followed by Ex Vivo Lung Perfusion using an Adeno-Associated Viral Vector in a Rodent Lung Transplant Model

Objective Ex vivo lung perfusion (EVLP) has emerged as a platform for organ preservation, evaluation, and restoration. Gene delivery using a clinically relevant Adeno-Associated Vector (AAV) during EVLP may be useful in optimizing donor allografts while the graft is maintained physiologically active. Here we evaluated the feasibility of AAV-mediated gene delivery during EVLP in a rat transplant model. Additionally, we assessed off-target effects and explored different routes of delivery. Methods Rat heart-lung blocks were procured and underwent 1-hour EVLP. Prior to EVLP, 4e11 viral genome luciferase (luc) encoding AAV9 was administered via the left bronchus (Br group, n=4), via the left pulmonary artery (PA group, n=3), or directly into the circuit (Circuit group, n=3). Donor lungs in the control group (n=3) underwent EVLP without AAV9. Only the left lung was transplanted. Animals underwent bioluminescence imaging weekly prior to sacrifice at two weeks. Tissues were collected for luc activity measurement. Results All recipients tolerated the transplant well. At 2-week posttransplant, luc activity in the transplanted lung was significantly higher among animals in the Br group, compared to the other three groups (Br: 1.1x106RLU/g, PA: 8.3x104RLU/g, Circuit: 3.8x103RLU/g, Control: 2.5x103RLU/g, p=0.0003). No off-target transgene expression was observed. Conclusions In this work, we demonstrate that a clinically relevant AAV9 vector mediates gene transduction during EVLP in rat lung grafts when administered via the airway and potentially the PA. Our preliminary results suggest a higher transduction efficiency when AAV9 was delivered via the airway and delivery during EVLP reduces off-target effects after graft implant.