Lung Function and Inflammatory Profiling of Damaged Rat Donor Lungs Following EVLP Thermal Preconditioning

Abstract

<h3>Purpose</h3> Ex-vivo lung perfusion (EVLP) is a validated technique allowing evaluation and reconditioning of damaged donor lungs to make them suitable for transplantation. Moderate hyperthermia is known to exert cytoprotective effect, via induction and accumulation of specific proteins, known as heat shock proteins (HSPs). We hypothesized that thermal preconditioning (TP) with a well-calibrated heat stress applied during EVLP could improve lung graft by reduction of oxidative stress, cell death and inflammation. <h3>Methods</h3> Male rats were randomly assigned into 2 groups: controls (Ctrl, n=5) or TP (n=5). In both groups, lungs were kept <i>in situ</i> for 1h at room temperature, then flushed with cold Perfadex. Heart-lung block was harvested and kept at 4°C for 1h, then mounted on the EVLP system for 3h. In Ctrl group, the temperature perfusion solution was kept at 37°C the all-time. In the TP group, a heat shock was done for 30 minutes after 1h of EVLP by heating the perfusion solution at 41.5°C. At the end of EVLP, lungs were snap-frozen and kept at -80°C for further tissue analysis. <h3>Results</h3> Static pulmonary compliance, peak inspiratory pressure, and oxygenation capacity were similar in both groups. We were able to induce HSPs in the TP group (<i>Hspa1a</i> and <i>Hmox-1</i>). In the TP group, we observed a reduction of oxidative stress (carbonyls and MDA), a decrease of apoptosis (Caspase 3 and 7) and a decrease of pro-inflammatory NF-κB transcription factor as well as the expression of inflammation mediators such as TNF-α, IL-1α, IL-1β, CXCL-1 and CCL-2. <h3>Conclusion</h3> Thermal preconditioning during EVLP decreased oxidative stress, apoptotic cell death, and inflammation of damaged lungs. These findings demonstrate that EVLP in association with thermal preconditioning could be a promising therapeutic platform improving lung quality of damaged donor lungs.