Small liver graft regenerates through immediate increase of HGF and IL-6 - Possible involvement of sinusoidal tensile/shear stress in small liver graft

Background/Aims: The mechanisms whereby grafts in the recipients can be primed for regeneration following living donor liver transplantation (LDLT) are poorly understood. The present study was designed to understand the mechanism for post-transplant regeneration in small-for-size liver graft. Methodology: Out of LDLT cases, we examined patients with end-stage liver cirrhosis and subsequent transplantation. A total of 16 patients were divided into 2 groups, group L (large graft) and group S (small graft). We examined the serum biochemical markers and cytokines preoperatively and postoperatively. We also carried out hemodynamic analysis by measuring the portal and arterial peak velocity. Results: The differences in ages, preoperative biochemical markers and MELD score between the two groups were not statistically significant. Though differences in the preoperative levels of IL-6, sIL-6R and HGF were not significant between the two groups, IL-6 and HGF levels in group S significantly increased postoperatively. Immediate and significant increase of Vp max was also observed in group S. Two weeks after LDLT, the regeneration rate in group S was significantly higher than that in group L. Conclusions: These findings may allow us to speculate that immediate increase of portal pressure, reflecting sinusoidal tensile/shear stress, accelerates liver regeneration through immediate induction of IL-6 and HGF.