Discriminate Liver Warm Ischemic Injury During Hypothermic Machine Perfusion by Proton Magnetic Resonance Spectroscopy: A Study in a Porcine Model

Abstract

Objective Proton magnetic resonance spectroscopy ( 1H MRS) is a technique to identify and quantify the composition of biofluids. Hypothermic machine perfusion (HMP) is an organ preservation method that has the potential to evaluate organ viability prior to transplantation by analyzing the composition of the perfusate. The aim of this study was to use 1H MRS to examine the perfusate during HMP of porcine livers exposed to warm ischemia (WI) and to identify potential biomarkers of liver viability. Materials and Methods Porcine livers underwent 4 hours of HMP using kidney perfusion solution-1 (KPS-1) as perfusate after exposure to in situ WI of 0 (n = 6) or 2 hours (n = 5). Samples of the perfusate were taken at the start/end of HMP. Lactate and aspartate aminotransferase (AST) in the samples were measured biochemically as surrogates of the WI-induced damage. MRS acquisition was conducted on a 9.4 Tesla (400 MHz) high-resolution system. Results AST increased significantly during 4 hours of HMP within groups ( P < .02) and discriminated WI injury significantly from the start to the end of HMP ( P < .03). 1H MRS showed significantly elevated signal intensity of lactate, alanine, and histidine during HMP within both groups ( P < .02). Furthermore, alanine and histidine were significantly higher in the WI group than in the control group at the end of HMP ( P = .011 and P = .038, respectively). Conclusion AST, alanine, and histidine in HMP perfusate discriminated WI injury on porcine liver grafts and might be potential biomarkers of liver viability.