Early hepatocyte C4d expression and failure to restore basal hepatic total protein content after ischaemia–reperfusion are associated with 1-year graft loss in human liver transplantation

Background and aims. Hepatic expression of several proteins, includng albumin, is reduced during ischaemia and restored upon reperfusion n human liver transplantation (LT) [J Pathol 2005;207:111–8]. Compleent activation during ischaemia reperfusion (IR) injury has been reported n renal, liver, intestine and heart allografts. A link between proteolysis nd complement activation has been demonstrated in myocardial IR damge [Proteomics 2002;2:988–95]. To better elucidate the mechanism and rognostic significance of complement activation in hepatic IR injury we easured early changes of liver graft C4d expression and total protein ontent (TP) during LT. Methods. Liver graft samples were obtained from heartbeating donors efore the aorta was clamped (T1) and 2 h after reperfusion in the recipint (T2) during primary whole organ LT. TP was measured by the Bio-Rad rotein assay method in freeze-dried liver homogenates from 47 grafts. In a ubgroup of 29 grafts C4d immunohistochemistry was performed on paraffin ections and positive hepatocytes were scored on a semiquantitative scale. he data were evaluated comparing grafts which were lost (LG) or survivng (SG) at 1-year follow-up. Intergroup differences were assessed by the ann–Whitney U-test. Correlations were analysed by the Spearman rank est. Results. LG (n= 10) had a significantly (p< 0.05) higher difference etween TP in T1 and in T2 ( TP) than SG (n= 37) (31.55± 31.51 vs. .41± 33.16 g/mg dry liver, respectively). C4d hepatocyte immunohistohemistry was negative in both LG and SG T1 samples. LG (n= 9) showed significantly (p< 0.05) higher T2 C4d hepatocyte score than SG (n= 20) 4.44± 1.67 vs. 2.55± 2.28 C4d, respectively). A positive correlation was ound between T2 C4d hepatocyte score and TP (r= 0.547, p< 0.01). Conclusions. Early complement activation and impaired restoring of raft protein content after reperfusion are linked events in hepatic ischaemia eperfusion injury and are associated with graft loss within the first year after uman LT.