An additive solution to expand the lung transplant organ pool

项目总结

PROJECT SUMMARY Major challenges in the field of lung transplantation are the low availability of healthy donor lungs (graft) and the damage to donor lungs post-transplant. These arise due to inflammation and oxidative damage initiated during the graft storage period. Among the multiple strategies employed to improve lung availability and transplant outcome are short storage times (comprising of < 3 h, storage under perfusion i.e. ex vivo lung perfusion or EVLP circuit, hypothermic storage, and the use of various antioxidant solutions) and immunosuppression therapy post-transplant. Of these, EVLP alone shows promise; however it is cost- prohibitive and often unavailable at the point of site of lung procurement. Immunosuppressive therapy, though partially effective is debilitating for the transplant recipient. Peroxitech LLC proposes to use an alternate strategy of blocking the earliest signaling events that are triggered during lung storage and that in turn lead to inflammation and injury. Work from the Chatterjee group has shown that pulmonary vascular wall responds to stop of blood flow associated with lung storage by activating an endothelial signaling cascade that leads to activation of NADPH oxidase 2 (NOX2) and reactive oxygen species (ROS) production. This group also reported that the phospholipase A2 (PLA2) activity of the enzyme Peroxiredoxin 6 is crucial in NOX2 activation. Recently, Peroxitech discovered a nine amino-acid peptide sequence (PIP-2) that can block the PLA2 activity of Prdx6 and thus diminish NOX2 activation and ROS production. Preliminary data shows that murine lungs stored in the 9 peptide aminoacid significantly reduced ROS production. ROS generation in lungs is well established to cause activation of inflammation and antigen presentation cascades which are signals for recruitment of innate (polymorphonuclear neutrophils or PMN) and adaptive immune cells (T lymphocytes) from the recipient. PMN adhere to the vessel wall of the newly transplanted lung (graft), transmigrate and release oxidants causing injury to the graft while activated T- lymphocytes drive lysis of the graft tissue. Peroxitech proposes to pre-“treat” donor lungs by blocking the signals during storage with PIP-2 (outside the body) such that PMN recruitment and T cell activation (both of which are ROS dependent) after transplant, is minimized. For this will evaluate PIP-2 as a lung preservation solution. We will in Aim 1) Evaluate PIP-2 formulations for effectivity in donor lung protection with increasing storage times and Aim 2) Evaluate the effect of PIP-2 as a preservation solution in murine lung transplant outcomes. If data obtained show that PIP-2 usage during lung storage leads to a significant reduction in inflammation, injury and an improved lung function, post-transplant, we will be enabled to proceed to Phase II with a full clinical and analytical evaluation of this agent in isolated human donor lungs, for an eventual FDA approval.