Normothermic ex vivo lung perfusion outperforms conventional cold preservation in a deceased rat lung

Utilization rate of donor lungs in China is constrained by the inefficiency of conventional cold preservation (COLD) in lung transplantation. We assessed the performance of normothermic ex vivo lung perfusion (EVLP) in lung donors following cardiac death (DCD) with fresh EVLP perfusate.

A total of 24 adult Sprague-Dawley (SD) rats were randomized into three groups (EVLP, COLD, and control groups) with 8 rats each. Fresh EVLP perfusate was prepared for lung perfusion. The pH, electrolyte concentration, perfusate penetration pressure during irrigation, physiological function, integrity of barrier function, pathological changes, and expressions of inflammation-related cytokines of donor lungs were examined.

The pH, electrolyte concentration, osmotic pressure of the perfusate were kept stable for 4 hours after EVLP was administered. Pulmonary arterial pressure (PAP), pulmonary venous pressure (PVP), pulmonary venous oxygenation index (PaO₂/FiO₂), and end carbon dioxide partial pressure (PCO₂) in the EVLP group were all within acceptable limits. After 4 hours, the oxygenation index was significantly higher in the EVLP group compared with that of the COLD group (P=0.0032). The EVLP group had a decreased wet/dry weight ratio (P=0.0155) and Evans blue dye content (P=0.0075) compared to that of the COLD group. Pathological examination showed more obvious lung damage in the COLD group than in the EVLP group. However, there was no difference in protein expression of high mobility group box 1 (HMGB1) and toll-like receptor 4 (TLR4) between the EVLP group and the COLD group.

Fresh lung perfusate could be used for EVLP to protect and repair donor lungs. Normothermic EVLP performed better than conventional cold preservation. EVLP might be powerful for lung quality maintenance and may have potential for anti-inflammation.