A proof of concept study on real-time LiMAx CYP1A2 liver function assessment of donor grafts during normothermic machine perfusion

Abstract

No single reliable parameter exists to assess liver graft function of extended criteria donors during ex-vivo normothermic machine perfusion (NMP). The liver maximum capacity (LiMAx) test is a clinically validated cytochromal breath test, measuring liver function based on 13CO2 production. As an innovative concept, we aimed to integrate the LiMAx breath test with NMP to assess organ function. Eleven human livers were perfused using NMP. After one hour of stabilization, LiMAx testing was performed. Injury markers (ALT, AST, miR-122, FMN, and Suzuki-score) and lactate clearance were measured and related to LiMAx values. LiMAx values ranged between 111 and 1838 µg/kg/h, and performing consecutive LiMAx tests during longer NMP was feasible. No correlation was found between LiMAx value and miR-122 and FMN levels in the perfusate. However, a significant inverse correlation was found between LiMAx value and histological injury (Suzuki-score, R = − 0.874, P < 0.001), AST (R = − 0.812, P = 0.004) and ALT (R = − 0.687, P = 0.028). Furthermore, a significant correlation was found with lactate clearance (R = 0.683, P = 0.043). We demonstrate, as proof of principle, that liver function during NMP can be quantified using the LiMAx test, illustrating a positive correlation with traditional injury markers. This new breath-test application separates livers with adequate cytochromal liver function from inadequate ones and may support decision-making in the safe utilization of extended criteria donor grafts.

Real-Time Assessment of Liver Function During Sub-Normothermic Machine Perfusion by a Non-Invasive 13C Based Test

“…The read-outs calculated from the novel 13 CO 2 13 C-Methacein response curves mirror the ndings described above irrespective of the perfusate. These ndings are in accordance with results reported for the similar 13 C-Methacetin based method in normothermic MP [14]. In combination with HMGB1 as well as FNM measurement, this 13 C-Methacetin based method proves to be a fast and reliable method to estimate liver function during SNMP.…”

“…It has been argued that one major limitation of the early breath tests using 13 C-Methacetin is the varying blood supply of the liver [13] but in terms of MP of an isolated organ, this argument might lose its strength. Furthermore, a very recent proof of concept study reported the feasibility of 13 CO 2 measurement in normothermic MP [14]. This study aimed to investigate for the rst time the feasibility to use a 13 C-Methacetin based test to assess liver function during sub-normothermic MP (SNMP) which has been reported to grant improved energy contents compared to normothermic MP in livers [15].…”

Donor eligibility criteria and liver graft acceptance criteria during normothermic regional perfusion: A systematic review

“…A potential substrate test might be the maximum liver function capacity (LiMAx) test, for which our research group already demonstrated the feasibility during normothermic machine perfusion. [ 31 ] Another approach is to assess in real time the integrity of the liver graft during aNRP with the use of Raman microspectroscopy. Ember et al [ 32 ] demonstrated that microvascular damage could be detected and potentially could assist the decision making during aNRP.…”

Cytochrome P450 2E1 predicts liver functional recovery from donation after circulatory death using air-ventilated normothermic machine perfusion

“…Expression and activity of liver cytochrome P450 isozymes were significantly changed after ischemia/reperfusion injury, indicating their use as biomarkers of function recovery during liver injury 22 , 23 . Cytochrome P450 1A2 was recently developed as a biomarker of liver function assessment during NMP, while the mechanism is unclear 24 . CYP2E1 is part of the cytochrome P450 family of drug-metabolizing enzymes in the liver.…”