LAUSR

Background There is no direct evidence for the role of angiogenesis in liver regeneration in humans. This study aimed to determine whether angiogenesis is involved in the regeneration of transplanted donor grafts in human living-donor liver transplantation (LDLT) and to examine the impact of donor graft volume on angiogenesis. Methods Clinical data and liver tissue characteristics were analyzed in 4 patients who received adult-to-adult LDLT with dual left lobe grafts from 2 living donors. Liver tissues from transplanted donor grafts were obtained and immunohistochemically examined at 3 to 4 weeks after transplantation using the endothelial marker Ki67+ and CD31+. Results All recipients showed recovery of normal liver function and a significant increase in the volume of engrafted left lobes after transplantation. Immunohistochemistry showed a remarkable increase in Ki67+ single hepatocyte proliferation, implying the role of hepatocytes in liver reconstitution, and a high density of blood vessels and proliferative endothelium, suggesting in vivo angiogenesis. Furthermore, we found that Ki67+ nuclei in CD31+ sinusoidal endothelial cells were higher in recipients with smaller donor grafts than in those with larger donor grafts. Conclusions Our results suggested that angiogenesis is involved in the regeneration of transplanted liver in humans in inverse proportion to the donor graft volume.