Intramucosal pH and liver endotoxin clearance during experimental liver transplantation

The study was designed to assess the gastrointestinal ischaemia and the influence of the specific Kupffer cell toxin gadolinium chloride (GdCl3) on the hepatic and extrahepatic endotoxin [lipopolysaccharide (LPS)] clearance during experimental orthotopic liver transplantation (OLT) in pigs. In eight pig liver transplantations, the donors received 20 mg/kg of GdCl3 24 h before explantation, while controls (n = 8) received normal saline. Gastric and sigmoid intramucosal pH (pHi), LPS and endotoxin-neutralising capacity (ENC) levels were measured in the portal vein and superior vena cava after laparatomy, at the end of the anhepatic phase and 1 h after reperfusion. During the anhepatic phase, the sigmoid pHi decreased significantly from 7.32 +/- 0.02 to 7.29 +/- 0.03 (P < 0.001) and was associated with a substantial increase of portal LPS. Following reperfusion, the systemic LPS concentrations were significantly lower in the pretreated group [39 +/- 23 pg/ml (Control); 14 +/- 7 (GdCl3); P < 0.05] suggesting an improved liver LPS clearance [86% (GdCl3); 58.2% (Control); P < 0.05]. This corresponded to an increased ENC in the pretreated group [118 +/- 52 ENU/ml (GdCl3) vs 81 +/- 45 ENU/ml (Control); P < 0.05]. The anhepatic phase induced splanchnic ischaemia which correlated with portal endotoxaemia. Donor preconditioning with GdCl3 leads to lower systemic LPS concentrations in the recipient and increases ENC values in the early phase after OLT. An improved hepatocellular LPS extraction and/or an activation of the extrahepatic reticulo-endothelial system as a result of GdCl3 treatment is discussed.