G. Panayotova1, F. Paterno1, M. Galan1, S. Simonishvili1, Y. Qin1, L. Brown1, A. Amin1, K. Lunsford1, J. V. Guarrera1 1Rutgers New Jersey Medical School, Transplant And HPB Surgery, Newark, NJ, USA
Introduction: Hypothermic oxygenated machine perfusion (HMP-O2) is a dynamic preservation technique that has shown great promise in mitigating ischemia/reperfusion injury (IRI) in liver transplantation; however, the associated molecular mechanisms are still largely undefined, particularly in the setting of biliary injury. Identifying markers of progressive/severe IRI would optimize graft monitoring and provide markers for targeted intervention. We sought to identify and compare perioperative biomarkers of liver and biliary injury following HMP-O2 vs standard of care cold storage (SCS).
Methods: Patients were transplanted at a single center as part of the PILOT trial (NCT03484455), the first prospective, multi-center randomized controlled trial of hypothermic oxygenated machine perfusion in the US. Livers were randomized to perfusion (HMP-O2) using the LifePort Liver Transporter (ORS, Itasca, IL) or to SCS. Preservation fluid (effluent) was collected prior to implantation. Bile duct (BD) and bile were collected 1hr post reperfusion. Effluent biochemistry was assessed via Luminex, and bile biochemistry via iSTAT-1/CG8+. Markers of tissue injury were identified by immunohistochemistry (IHC).
Results: Liver transplant was performed in 20 patients (7 HMP-O2 ; 13 SCS). Baseline donor and recipient characteristics were similar between groups. Cold time was significantly longer for HMP-O2 vs SCS (6.9±0.9 vs 5.4±1, p<0.001). Early allograft dysfunction (EAD) occurred in three cases, all SCS. HMP-O2 resulted in fewer post-operative complications: fewer re-admissions, re-interventions, and biliary complications (Comprehensive Complication Index, 42 vs 56, p<0.05). Multiplex biomarker analysis of effluent showed attenuated expression of canonical inflammatory markers (MIP-1ß, IL-10, IL-8, IL-6, TNFα ) following HMP-O2 (Figure 1). Cholangiocyte function, reflected by lower bile glucose, was preserved post HMP-O2 vs SCS (55 vs 156 mg/dL, p<0.05). IHC of BD tissue demonstrated attenuated activation of inflammation (NF-κß, p=0.4), reactive proliferation (Ki-67, p<0.05), and necroptosis (RIP-3, p<0.05) following HMP-O2, suggesting decreased biliary injury. The most intense staining was noted in an SCS case which developed biliary leak and anastomotic breakdown.
Conclusion: HMP-O2 provides safe and effective preservation for liver allografts. Perfusion decreases inflammatory signaling, reactive tissue proliferation, and tissue necroptosis. This likely confers protection from IRI and leads to improved post-transplant outcomes. The novel application of multiplex assessment of effluent may identify biomarkers of early injury for targeted intervention to improve liver transplant outcomes.
