Background. A comprehensive mechanistic assessment of normothermic machine perfusion (NMP) is an essential step toward identifying biomarkers to assess liver viability. Although some studies have evaluated the effect of NMP on inflammation markers, there are other key pathological mechanisms involved in ischemia/reperfusion injury (IRI) that have not yet been evaluated. Methods. Eight human donor livers preserved by NMP were included to analyze IRI during preservation. Concentrations of several biomarkers involved in different biological processes of IRI were measured in the perfusate. Results. Perfusate levels of intercellular adhesion molecule 1, P-selectin, vascular cell adhesion molecule 1, metalloproteinase with thrombospondin motif type 1, member 13, phospholipase A2 group VII, and syndecan-1 progressively increased during NMP. Noteworthy, perfusate lactate levels showed a strong correlation with C-X-C motif chemokine ligand 10 (P = 0.001), intercellular adhesion molecule 1 (P = 0.01), and urokinase plasminogen activator (P = 0.001). Conclusions. Perfusate lactate correlates with the main underlying biological mechanisms occurring in the NMP environment. Moreover, several IRI biomarkers accumulate during NMP, which may limit the extent of the benefits of this technology.
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