Increased sinusoidal pressure is associated with early liver weight gain in ischemia-reperfusion injury in isolated perfused rat liver

Background. Hepatic ischemia-reperfusion (I/R) is accompanied by liver weig ht gain and ascites formation. This could be caused by an increase in sinus oidal pressure, a determinant of hepatic transvascular fluid movement. We d etermined the role of sinusoidal pressure, assessed by triple vascular occl usion pressure (P-to), in the I/R injury in isolated rat livers perfused wi th leukocyte-free diluted blood bivascularly via the portal vein and hepati c artery. Materials and methods. Ischemia was induced at room temperature by occlusio n of either the inflow lines of the hepatic artery and portal vein (the ope n outflow group, n = 10) or both the inflow and the outflow (hepatic venous ) lines (the closed outflow group, n = 10) for 1 h, followed by 1-h reperfu sion in a recirculating manner, Results. Liver weight in both groups increased biphasically after reperfusi on; the initial peak occurred at 3 min and the second peak at 60 min. Immed iately after reperfusion, P-to peaked, followed by a gradual decline. The i nitial weight increase in groups combined was significantly and positively correlated with an increase in P-to (r = 0.716, P = 0.0002), but the second peak was independent of P-to. Liver injury, assessed by perfusate levels o f hepatic enzymes and reduced bile flow rate, was observed at 60 min after reperfusion in both groups. Conclusions. These findings suggest that increased sinusoidal pressure cont ributes to only the early liver weight gain after reperfusion in isolated p erfused rat livers. The late weight gain may be presumably due to liver inj ury. (C) 2000 Academic Press.