Increased Serum Phospholipase A2 Activity After Non-Heart-Beating Donor Liver Transplantation and Association With Ischemia-Reperfusion Injury

BackgroundSecretory phospholipase A2 (sPLA2) degrades cell membrane phospholipids and plays an important role in the synthesis of pro-inflammatory lipid mediators (arachidonic acid and cytokines) during inflammatory events such as ischemia-reperfusion injury after liver transplantation (LTx). A role for sPLA2 in LTx from non-heart-beating donors (NHBD) has never been demonstrated. Furthermore data on the natural sPLA2 inhibition capacity are scarce.Materials and methodsUsing our previously validated pig model of NHBD-LTx, we evaluated changes in sPLA2 enzyme activity in serum early after reperfusion of livers exposed to warm ischemia. Porcine livers were exposed to incremental periods of warm ischemia, procured, and transplanted after 4 h of cold storage. In serum samples, collected prior to and after reperfusion, sPLA2 enzyme activity, tumor necrosis factor-α, and interleukin-6 levels were determined.ResultsAfter reperfusion, sPLA2 activity increased and peaked significantly at 60 min in recipients with primary nonfunction (PNF). Tumor necrosis factor-α and interleukin-6 peaked later (at 180 min) in these PNF recipients. We observed a strong natural inhibition of sPLA2 activity in serum at baseline; this inhibition was substantial reduced 1 h after reperfusion in both PNF and non-PNF recipients. In the non-PNF recipients, however, this natural PLA2 inhibition was restored within 24 h after reperfusion.ConclusionsThis study suggests that an increased sPLA2 activity and a reduced inhibition may play an important role in the pathogenesis of ischemia-reperfusion injury of NHBD liver grafts.