Impact of platelets and serotonin on liver regeneration after living donor hepatectomy.

BACKGROUND: Several animal models have revealed that platelet-derived serotonin initiates liver regeneration after hepatectomy. However, there are few reports regarding the effects of serotonin in the clinical setting. The aim of this study was to explore the impact of serotonin and platelets in the early phase after healthy living donor hepatectomy. STUDY DESIGN: Stored samples from 34 living donors who received left lobectomy with caudate lobectomy (LL+C) or right lobectomy (RL) were available in the study. Serum serotonin levels and platelet counts associated with liver regeneration such as whole liver volume and hepatic graft weight (GW) were retrospectively collected from the database and analyzed. RESULTS: The remnant liver volume rate of RL grafts was smaller than that of LL+C grafts (45.4% vs 64.7%; P < .001). The regeneration rate at 7 days after surgery did not differ between the 2 groups (123% vs 122%). The serotonin levels and platelet counts decreased after surgery until postoperative day 3, then increased thereafter. The platelet counts and serotonin levels of LL+C donors were significantly higher than those of RL donors. CONCLUSIONS: Our findings suggest that platelets and serotonin play a pivotal role in initiating liver regeneration in the remnant liver.