Novel Mouse Model of Hypothermic Oxygenated Ex Vivo Lung Machine Perfusion

Background: Ex vivo lung perfusion (EVLP) allows the evaluation, treatment, transport, and long-term preservation of grafts prior to transplantation. This approach also serves as a comprehensive experimental platform for targeted evaluation of cancer response to chemotherapeutic agents ex vivo. The high availability of genetically modified mouse models of lung disease provides an excellent opportunity to develop a murine EVLP model for cancer and transplantation studies. Currently, there is no established translational model of the murine hypothermic lung machine perfusion known. Therefore, the aim of our study was to develop and test a mouse model that combines continuous oxygenation of the perfusion medium with simultaneous respiration of the lungs, providing the necessary temperature conditions.

Methods: The ex vivo oxygenated lung perfusion circuit consisted of two reservoirs, a micro-oxygenator, a pump for lung perfusion, a filter system, and a tubing system. Cannulation for oxygenated perfusion was done using a 1-Fr catheter in the common pulmonary artery. Tracheal cannulation for ventilation was performed with an 18-G cannula. Cooling was performed using Peltier hardware. Ventilation of the lungs was performed via an additional connection to a small animal ventilator. The oxygenator of the perfusion circuit was supplied with pure oxygen at a flow rate of 0.5 L/min. The perfusion medium was Krebs-Hanseleit solution supplemented with dextran, mannitol, and HEPES.

Results: A stable, fully functional mouse ex vivo lung perfusion system has been established. Starting from normothermia or room temperature, rapid cooling of the oxygenated medium to 8 °C was easily achieved. Stable temperature maintenance, oxygenation of the medium, and perfusion via pulmonary artery were performed for 6 hours. Blood gas measurement in both inflow and outflow perfusate during room air ventilation of the lungs without oxygenation after rewarming showed a pO2 gradient above 100 mm Hg and decarboxilation to 20%. Enrichment of the medium with both mannitol and dextrane significantly reduced tissue edema. No accumulation of lactate in the medium was observed during perfusion.

Conclusion: The stable performance of the ex vivo lung perfusion system in the mouse has thus been demonstrated. Our murine model of oxygenated hypothermic lung perfusion opens up new opportunities to study different treatment and preservation strategies for extended criteria donor lungs, as well as cancer research using ex vivo models. A further extension of the perfusion time to 24 hours is planned in our set-up.

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Artikel online veröffentlicht:
11. Februar 2025