Impact of Splenectomy Just before Partial Orthotopic Liver Transplantation Using Small-for-Size Graft in Rats

Background Portal hypertension is a serious obstacle of partial orthotopic liver transplantation (POLT) with the use of small-for-size liver graft. Several therapeutic strategies including surgical innovations and pharmacological agents to reduce the portal hypertension have been developed. Splenectomy (SP) on POLT is one of surgical procedures to reduce portal pressure. We previously reported a dual cytoprotective mechanism of SP just before POLT, using small-for-size liver graft in a rat model. However, the best timing of SP during POLT has been unclear. We compared liver functions between SP just before and after POLT, using small-for-size rat liver grafts. Methods With the use of small-for-size liver grafts (20%) in rats previously reported, the rats were assigned to 2 groups: the pre-SP group (SP just before POLT) and the post-SP group (SP just after POLT). Liver tissues and blood were sampled at 6 and 24 hours after POLT for several liver function tests. Results The serum alanine aminotransferase levels at 24 hours after POLT were significantly decreased in the pre-SP group compared with the post-SP group (226 ± 78 vs 340 ± 71 IU/L). The infiltrations of neutrophil at 6 hours and ED-1-positive cells at 24 hours were significantly suppressed in the pre-SP group compared with the post-SP group. Serum hyaluronic acid levels, indicating attenuation of endothelial damage, were lower in the pre-SP group than in the post-SP group. Conclusions SP before POLT, which directly eliminates splenic inflammatory leukocytes, inhibits inflammatory leukocyte infiltration, which leads to impaired liver function as compared with SP after POLT.