Forest plots comparing peak AST, Peak LDH, and ALT for all studies comparing different MP to CS in animal studies. (a) Peak AST. NMP (SMD: 0.12, 95% CI:-0.87 to 1.11) increased the release of AST, while SNMP (SMD: -0.61, 95% CI:-1.58 to 0.36) and HMP (SMD: -0.87, 95% CI:-1.76 to 0.02) reduced the release of AST; (b) peak LDH. NMP (SMD: -0.77, 95% CI: -2.45 to 0.92), HMP (SMD:-1.37, 95% CI: -2.95 to 0.22), and SNMP (SMD: -3.16, 95% CI: -5.14 to -1.18) reduced the release of LDH; (c) ALT. NMP (SMD:-0.59, 95% CI: -2.24 to 1.06) and SNMP (SMD:-2.46, 95% CI: -4.03 to -0.90) reduced the release of ALT. AST: aspartate aminotransferase; LDH: lactate dehydrogenase; ALT: alanine aminotransferase; MP: machine perfusion; HMP: hypothermic machine perfusion; NMP: normothermic machine perfusion; SNMP: subnormothermic machine perfusion; CS: cold static storage; SMD: standardized mean differences.