Influence of extracorporeal porcine liver perfusion on nonhuman primates: Minimizing hemolysis improves subsequent survival

Abstract

The aim of this study is to detect and analyze risk factors of direct cross-circulation between porcine liver and nonhuman primates before a clinical application of extracorporeal liver perfusion (ECLP) as a liver-assist method. Porcine livers were perfused with baboon blood in an ECLP system. Six healthy baboons were directly connected to the ECLP system with continuous prostaglandin E 1 administration. Cross-circulation was terminated in the following circumstances: (1) E xtracorporeal liver perfusion (ECLP) is a temporary liver-assist method. First reported by Otto et al, 1 it was studied extensively during the 1960s to 1980s. 2-5 ECLP was found to improve the neurological status of patients with acute hepatic failure by facilitating the removal of such toxic substances as ammonia and bilirubin. 6 Since the 1980s, orthotopic liver transplantation has become the established treatment of choice for severe acute hepatic failure, and ECLP was not studied for a time. However, a chronic shortage of human livers available for transplantation and the possibility that the need for transplantation might be averted encouraged renewed interest in liver-assist methods. Thus, ECLP now is being reevaluated as a therapeutic modality of intervention in patients with acute hepatic failure. 7-9 However, to date, there have been no preclinical studies that evaluated the safety of ECLP in nonhuman primates.We developed a new ECLP system using a whole porcine liver as a liver-assist device. The administration of prostaglandin E 1 , which ameliorates injury mediated by xenogeneic humoral factors, has enabled the xenoperfused porcine liver to be kept viable for 9 hours in a closed circuit. [10][11][12][13] The metabolic capacity of this ECLP system has been pharmacokinetically analyzed using galactose-, lidocaine-, and ammonia-loading tests and documented to maintain functional capacity similar to that of in situ porcine livers for up to 9 hours. 14 Before an application of the ECLP system in the clinical arena, a preclinical assessment using nonhuman primates is a prerequisite. Because symptoms of acute hepatic failure vary, it is difficult to distinguish potential complications of ECLP from complications of the underlying liver disease. In this preclinical study, healthy baboons were used to investigate the influences of the ECLP system on primates.

Pig-to-Baboon Liver Xenoperfusion Utilizing GalTKO.hCD46 Pigs and Glycoprotein Ib Blockade.

“…These studies have been in pre-clinical large animal models utilizing both hepatocyte-based devices [12,13] and whole-organ liver perfusion [14], as well as in limited clinical applications using porcine hepatocytes or whole livers [2,[15][16][17][18]. In our present report, we utilize a genetically modified GalTKO.hCD46 porcine liver designed to eliminate hyperacute rejection while simultaneously attempting to interfere with the constitutive activation between VWF and the GPIb receptor by administering D-arginine vasopressin (DDAVP) and αGPIb antibody.…”

Absence of PERV infection in baboons after transgenic porcine liver perfusion1

“…The pigs were fasted for 24 h prior to surgery. Porcine livers were completely dissected from the surrounding tissues and procured during in situ rapid flushing with 1,500 ml of cold (4°C) heparinized Ringer's lactate solution via both the portal vein (PV) and the hepatic artery (HA) [21,22]. The bile duct was cannulated to drain the bile from the liver.…”

“…The h-DAF porcine liver was perfused with baboon blood in our ECLP system as described elsewhere [22,23]. Hydroxycortisone (100 mg/L), ampicillin (500 mg/L), and low-molecular-weight heparin (5 U/mL, dalteparin sodium, Kissei Pharmaceutical Co., Ltd., Tokyo, Japan) were added to the perfusate before the perfusion.…”

“…Cross-circulation between the ECLP and baboons was performed as described previously [22,23]. To evaluate liver graft injury, portal vein (PV) and hepatic artery (HA) pressures, exudate from the graft, and bile production were monitored.…”

“…This system is comparable to in situ liver or allo-perfused livers for at least 9 h [21]. We also have performed a cross-circulation between nonhuman primates and the ECLP system, using healthy baboons as recipient animals [22]. Maximally 6 h of ECLP resulted in mild hemolysis in these animals, but they maintained good health after the procedure.…”