Ultrastructural study of the remnant liver after extensive hepatectomy in dogs; especially morphological alterations of sinusoidal endothelial cells.

Background/Aims: To investigate the role of sinusoidal endothelial cells in the mechanism of the remnant liver dysfunction after extensive hepatectomy, morphological alteration of sinusoidal endothelial cells and cytoprotective effects of prostaglandin I 2 analog were studied by ultrastructural analysis. Methodology: Mongrel dogs (n=24) were divided into 3 groups according to the extent of hepatectomy and the use of prostaglandin I 2 analog preoperatively. Group 1: 70% hepatectomy (n=8), Group 2: 84% hepatectomy (n=8), and Group 3: 84% hepatectomy with administration of prostaglandin I 2 analog, preoperatively (n=8). Morphology of hepatic sinusoidal endothelial cells was examined after hepatectomy in all cases. Results: Group 2: Enlargement of the sinusoidal endothelial fenestrations was transitorily occurred immediately after hepatectomy, but were dramatically decreased in size 24h after the operation. Most sinusoidal endothelial cells were destroyed and separated from the sinusoidal wall. Fibrin deposits and sludge were found in the Disse's space and sinusoidal lumens, resembling liver failure at 24h after the operation. Group 1 and 3: sinusoidal endothelial fenestrations remained slightly enlarged at 24h after the operation, but fibrin deposits or sludge were not observed in sinusoidal lumens. Conclusions: Our data suggest that extensive hepatectomy changed the morphology of sinusoidal endothelial cells. Administration of prostaglandin I 2 analog helped maintain structural integrity of sinusoidal endothelial cells, improved hepatic microcirculation and thus served to reduce remnant liver dysfunction.