Normothermic machine perfusion of donor livers without the need for human blood products

Abstract

Normothermic machine perfusion (NMP) enables viability assessment of donor livers prior to transplantation. NMP is frequently performed by using human blood products including red blood cells (RBCs) and fresh frozen plasma (FFP). Our aim was to examine the efficacy of a novel machine perfusion solution based on polymerized bovine hemoglobin-based oxygen carrier (HBOC)-201. Twenty-four livers declined for transplantation were transported by using static cold storage. Upon arrival, livers underwent NMP for 6 hours using pressure-controlled portal and arterial perfusion. A total of 12 livers were perfused using a solution based on RBCs and FFPs (historical cohort), 6 livers with HBOC-201 and FFPs, and another 6 livers with HBOC-201 and gelofusine, a gelatin-based colloid solution. Compared with RBC + FFP perfused livers, livers perfused with HBOC-201 had significantly higher hepatic adenosine triphosphate content, cumulative bile production, and portal and arterial flows. Biliary secretion of bicarbonate, bilirubin, bile salts, and phospholipids was similar in all 3 groups. The alanine aminotransferase concentration in perfusate was lower in the HBOC-201-perfused groups. In conclusion, NMP of human donor livers can be performed effectively using HBOC-201 and gelofusine, eliminating the need for human blood products. Perfusing livers with HBOC-201 is at least similar to perfusion with RBCs and FFP. Some of the biomarkers of liver function and injury even suggest a possible superiority of an HBOC-201-based perfusion solution and opens a perspective for further optimization of machine perfusion techniques. Liver Transplantation 24 528-538 2018 AASLD.

Figure 1

Photographs of donor livers during NMP. (A) NMP using a perfusion fluid based on RBC + FFP. (B) NMP using a perfusion fluid based on HBOC‐201 + gelofusine. The supratruncal hepatic artery (large arrow), portal vein (arrowhead), and bile duct (thin arrow) are cannulated. Note the darker color of the HBOC‐201 perfusion solution.

Figure 2

Portal vein, hepatic artery, and total flow during NMP. (A) The portal vein flow during NMP was significantly higher at each time point after the first hour in both HBOC‐201 groups compared with the RBC + FFP group. (B) The hepatic artery flow was significantly higher after the first 2 hours of NMP in the HBOC‐201 + FFP group compared with the RBC + FFP group. (C) The total (portal vein + hepatic artery) flow during NMP remained significantly higher at nearly each time point after the first hour in both HBOC‐201 groups compared with the RBC + FFP group. There were no significant differences in hepatic or portal vein flow between the 2 HBOC‐201 groups. *Significant difference between RBC + FFP and HBOC‐201 + FFP; †significant difference between RBC + FFP and HBOC‐201 + gelofusine. Median and IQR values are shown.

Figure 3

ATP content in liver parenchyma, cumulative bile production, and cumulative biliary secretion of bicarbonate, bilirubin, bile salts, and phospholipids during 6 hours of NMP. (A) The hepatic ATP content was highest in the HBOC‐201 + gelofusine group, followed by the HBOC‐201 + FFP group, and lastly the RBC + FFP group at each time point. (B) Cumulative bile production during NMP was significantly higher at each time point in both HBOC‐201 groups compared with the RBC + FFP group, after the second hour of NMP. (C) The cumulative secretion of bicarbonate, bilirubin, bile salts, and phospholipids in bile during 6 hours of NMP was not significantly different between the 3 study groups. *Significant difference between RBC + FFP and HBOC‐201 + FFP; †Significant difference between RBC + FFP and HBOC‐201 + gelofusine. Median and IQR values are shown.

Figure 4

Lactate and glucose concentrations in perfusion fluid during NMP. (A) The perfusate lactate concentration declined more quickly in the HBOC‐201 groups compared with the RBC + FFP group, with an approximately 2‐fold higher median lactate concentration at 2 hours NMP in the RBC + FFP group compared with the HBOC‐201 perfused groups. There were, however, no significant differences in perfusate lactate concentrations between the 3 groups. (B) Although glucose concentration during NMP normalized more quickly in the HBOC‐201 groups compared with the RBC + FFP group, this did not reach statistical significance. Median and IQR values are shown.

Figure 5

ALT concentration in perfusion fluid during NMP. The ALT concentration is higher in the RBC + FFP group compared with both HBOC‐201 groups during NMP, nearly reaching significance at 4 hours of NMP (both P = 0.07) and at 6 hours of NMP between the RBC + FFP and HBOC‐201 + FFP groups (P = 0.06). Median and IQR values are shown.

Figure 6

Histological liver injury. Representative H & E stainings of liver biopsies prior to and after 6 hours NMP in each study group. There were no significant differences in the degree of liver injury between the 3 study groups before or after NMP. Arrowheads indicate necrotic cells. (A) Liver section of an RBC + FFP liver prior to NMP. (B) Liver section of the same RBC + FFP liver after 6 hours NMP. (C) Liver section of an HBOC‐201 + FFP liver prior to NMP. (D) Liver section of the same HBOC‐201 + FFP liver after 6 hours NMP. (E) Liver section of an HBOC‐201 + gelofusine liver prior to NMP. (F) Liver section of the same HBOC‐201 + gelofusine liver after 6 hours NMP.