Development of a Rat Liver Machine Perfusion System for Normothermic and Subnormothermic Conditions

Abstract

Ex vivo liver machine perfusion (MP) is a promising alternative for preservation of liver grafts from extended criteria donors. Small animal models can be used to evaluate different perfusion conditions. We here describe the development of a miniaturized ex vivo MP system for rat liver grafts, evaluating cell-free and erythrocyte-based perfusion solutions, subnormothermic and normothermic temperatures, and dialysis. A perfusion chamber was designed after a suitable liver position was identified. Normothermic ex vivo liver perfusion (NEVLP) required supplementation of erythrocytes to reduce cell damage. Perfusion with erythrocytes led to rising potassium levels after 12 h (NEVLP, 16.2 mM, interquartile range [IQR]: 5.7 and subnormothermic ex vivo liver perfusion [SNEVLP], 12.8 mM, IQR: 3.5), which were normalized by dialysis using a laboratory dialysis membrane (NEVLP, 6.2 mM, IQR: 0.5 and SNEVLP, 5.3 mM, IQR: 0.1; p = 0.004). Livers treated with NEVLP conditions showed higher bile production (18.52 mg/h/g, IQR: 8.2) compared to livers perfused under SNEVLP conditions (0.4 mg/h/g, IQR: 1.2, p = 0.01). Reducing the perfusion volume from 100 to 50 mL allowed for higher erythrocyte concentrations, leading to significantly lower transaminases (15.75 U/L/mL, IQR: 2.29 vs. 5.97 U/L/mL, IQR: 18.07, p = 0.002). In conclusion, a well-designed perfusion system, appropriate oxygen carriers, dialysis, and miniaturization of the perfusion volume are critical features for successful miniaturized ex vivo liver MP.

Dual versus single vessel normothermic ex vivo perfusion of rat liver grafts using metamizole for vasodilatation

“…compared single and dual vessel NEVLP but were unable to accomplish perfusion periods of longer than 90 minutes without witnessing a severe escalation of arterial perfusion pressure and transaminase levels [ 30 ]. Reasons for that could include the lack of a dialysis circuit and the utilization of a cell free perfusate, as previous findings of our work group show [ 31 , 23 ]. Brüggenwirth et al .…”

The effect of blood cells retained in rat livers during static cold storage on viability outcomes during normothermic machine perfusion

“…Both group 1 and group 3 livers had mean ALT levels within transplantable criteria during 6 hours of NMP while group 2 and group 4 livers did not meet ALT transplantable criteria by 6 hours. [25,31] The differences in mean ALT levels between group 2 and 3 livers did not reach statistical signi cance by 6 hours (492 ± 98 vs. 278 ± 91 units/L, p = 0.069) (Fig. 3B).…”

“…Both group 1 and group 3 livers had mean AST levels within transplantable criteria during 6 hours of NMP while group 2 and group 4 livers did not meet AST transplantable criteria by 6 hours. [25,31] Compared to cold UW ush livers with SCS (group 2), RT LR ush livers with SCS (group 3) had lower mean AST levels at 6 hours of NMP (629 ± 121 vs. 351 ± 97 units/L, p = 0.046) (Fig. 3A).…”

Rapid Metabolic Recovery of Donor Circulatory Death Liver Graft Using Whole Blood Perfusion: A Pig Study

“… 6 However, it has been reported that metabolism can be suppressed by reducing the perfusion temperature, and studies have been conducted to investigate the metabolic status of the perfusate in ex vivo perfusion. 11 , 12 Based on these studies, metabolic studies in pigs are of great value because the metabolism of pigs is similar to that of humans. The required components of ex vivo perfusion were examined by comparing perfusion ex vivo with 10% diluted blood and whole blood collected from donors.…”