Hepatic indocyanine green uptake and excretion in a rabbit model of steatosis

Transplantation of a fatty liver is associated with a higher incidence of p rimary non-function of the graft. Indocyanine green (ICG) has been used for assessing hepatic dysfunction but not for quantifying liver steatosis. New Zealand white rabbits were fed a normal diet (group A) or a high-cholester ol (2%) diet for 4, 8, and 12 weeks in groups B, C, and D, respectively. La parotomy was performed for liver exposure. Hepatic artery, portal vein, and total blood flow, hepatic microcirculation, portal pressure, liver functio n parameters,and blood cholesterol levels were measured. The hepatic ICG co ncentration was measured using near-infrared spectroscopy, and its uptake a nd excretion rates were calculated. The severity of steatosis was assessed from liver biopsy specimens by a semiquantitative grading system. Cholester ol feeding resulted in mild steatosis after 4 weeks and in moderate steatos is after 8 and 12 weeks. Mild steatosis was associated with insignificant c hanges in haemodynamic parameters, liver function, and ICG handling as comp ared with controls. Moderate steatosis caused a significant reduction in po rtal and total hepatic blood flow and microcirculation with a significant i ncrease in hepatic artery flow and portal pressure. These haemodynamic chan ges were associated with a significant alteration in liver function tests. With moderate steatosis, ICG uptake and excretion were significantly reduce d. The ICG uptake rate significantly correlated with total blood flow and m icrocirculation. The ICG excretion rate significantly correlated with the c hanges in bilirubin, liver enzymes, and albumin. Direct ICG quantification by near-infrared spectroscopy could be used to assess the severity of hepat ic steatosis by reflecting impaired parenchymal perfusion and liver dysfunc tion. Copyright (C) 2001 S. Karger AG, Basel.