At the same time, the globally sustained hypoxic pulmonary vasoconstriction allows for a limit on the shunt effect and maintains gas exchanges. Such mechanisms may account for the alterations of capillary-alveolar function coexisting with normal

blood gases that was observed in our lungs treated with 30 μM of CsA. A possible limit encountered in our study might be the short ischemic time (135 ± 21 minutes) to which our lungs have been exposed. Indeed, a longer ischemia may provoke a more severe IRI and perhaps give the opportunity for the CsA to emphasize its positive effects. Nevertheless, the duration of ischemia in our model was similar to several other studies performed with CsA [15, 25, 30]. A possible bias may also be related to the induction of anesthesia with Isoflurane CX-4945 in vitro in live animals. Indeed, several works show that halogen gases inhibit the MPTP [10, 23, 31, 34], which could interfere with the CsA action in the prevention

of IRI. This preventive action was expected for Sevoflurane [10, 31], while Isoflurane showed contrasting results [23, 34]. In our protocol, Isoflurane was only used for the induction of general anesthesia before euthanasia and lung procurement surgery. As observed in the exhaled gas analysis we assumed that there was almost no gas left in the alveoli at reperfusion time. Moreover, Isoflurane has been used in every group, thus limiting the effects of possible drug interference in the results analysis. IRI prevention is a major challenge in lung transplantation. In our pig EVLP model, CsA showed a dose-dependent

improvement in PaO2/FiO2 ratio that may be related to a parallel enhancement of hypoxic pulmonary vasoconstriction. Low Galunisertib doses of CsA showed a non-significant trend toward an improvement in capillary-alveolar membrane IKBKE injury. Lungs treated with high doses of CsA (30 μM) presented an aggravation in lung permeability and cytokines concentrations, suggesting a deleterious imbalance between the possible beneficial properties of CsA on IRI cells and their hemodynamic effects in microvascularization. Further studies should focus more on lungs subjected to longer ischemia and treated with low or moderate doses of CsA. We evaluated for the first time the effects of CsA on IRI in ex vivo reperfused pig lungs. Our data suggests a possible deleterious imbalance between the beneficial cell properties of CsA and its hemodynamic effects on microvascularization. For future experiments, it would be interesting to focus more on smaller doses of CsA which might limit hemodynamic drawbacks on lung microcirculation, while keeping their beneficial cellular effect on IRI. Unlike our experiment, in which the length of cold ischemia was limited, other experiments should test CsA in various cold ischemic time situations (i.e., broad spectrum of IRI severity) for highlighting the efficacy of CsA. This study was funded by the French Health Ministry and by the association “Vaincre la mucoviscidose.” We thank Mr.