199 Effectiveness of hypothermic machine perfusion and static cold storage as delivery methods of a novel RIPK1 inhibitor into pig kidneys and its effects on ischaemia-reperfusion injury Free

Ischaemia-reperfusion injury (IRI) is inevitable in transplantation. Necroptosis is a form of cell death in kidney IRI and phosphorylation of RIPK1 plays a key role in this pathway. This study investigated the effectiveness of delivering GNE684 -a RIPK1 kinase inhibitor- during static cold storage (SCS) and hypothermic machine perfusion (HMP) in an ex-vivo model of kidney IRI.

Pig kidneys underwent 1h warm ischaemia and were retrieved. In the SCS model, kidney pairs (n=6) were randomised to treatment with UW+GNE684 via the renal artery (5µM) or control. Kidneys underwent 7h SCS in UW±GNE684 followed by 4h ex-vivo normothermic reperfusion with whole blood (NR). In the HMP model, kidney pairs (n=6) were randomised to HMP alone or treatment with UW-MPS+GNE684 (5µM) for 12h followed by 8h NR.

In both SCS and HMP groups increasing levels of cytokines and injury markers (e.g. LDH, AST, IL-6) were observed without significant differences between control and treatment groups. HMP led to higher GNE684 tissue concentrations post preservation compared to SCS (3143±385.9 vs 1036.22±453.49ng/ml;P<0.0001) and during NR (987.5±507.6 vs 213.7±37.37ng/ml at t=4h;P=0.013) and levels stayed steady until t=8h NR. GNE684 in both models reduced pRIPK1 at 1h NR but the effect persisted at 4h NR in the HMP model.

This study showed the superiority of HMP over SCS as a delivery method of GNE684 to ischaemically injured pig kidneys. GNE684 did not have marked effects on inflammation or IRI but did inhibit RIPK1 activation in the necroptosis pathway.