*Purpose: Hepatic ischemia-reperfusion injury (IRI), an innate-immune driven hepatic inflammation response, represents a major risk factor of early allograft dysfunction (EAD) and rejection in liver transplantation (LT). We and other have reported on anti-inflammatory and hepatoprotective functions of β-catenin signaling in a mouse warm IRI model, whereas its clinical relevance remains to be determined. By screening primary mouse hepatocyte cultures and human LT biopsies (Bx) in parallel, we aimed to investigate the influence of graft β-catenin activation on hepatocyte protection, graft inflammation and LT outcomes.

*Methods: Primary mouse hepatocyte cultures (stressed with H2O2) with or without adjunctive β-catenin silencing (siRNA) were evaluated by Western blots (WB) for pro-apoptotic cleaved caspase-3 (CC3) and cleaved caspase-8 (CC8) levels. Human liver Bx were obtained at 2 hours post-reperfusion (prior to abdominal closure) from LT patients recruited under IRB protocol (n=21). Hepatic Bx samples were screened by WB/RT-PCR, while β-catenin activation was evaluated by detecting its active form (non-phospho-β-catenin, AcBc) by WB.

*Results: In hepatocyte cultures, β-catenin silencing enhanced CC3 and CC8 levels under H2O2 stress, indicating cytoprotective role of hepatocyte β-catenin signaling. In clinical LT Bx, AcBc levels negatively correlated with protein levels of CC3 (r=-0.4805, p=0.0275) and CC8 (r=-0.5701, p=0.0070). Moreover, AcBc expression negatively correlated with mRNA levels coding for 1/ TLR2 (r=-0.6961, p=0.0005), TLR4 (r=-0.4234, p=0.0558), TLR9 (r=-0.4221, p=0.0567); 2/ CD80 (r=-0.4545, p=0.0384), CD86 (r=-0.4494, p=0.0410), CXCL10 (r=-0.3935, p=0.0776), macrophage activation markers; 3/ CD4 (r=-0.3740, p=0.0949), CD28 (r=-0.4584, p=0.0366), T-cell activation markers; 4/ while positively correlating with Arg1 (r=0.5091, p=0.0184), an anti-inflammatory macrophage marker. To evaluate the predictive power of AcBc for graft loss, a cut-off value was decided based on the ROC curve (AUC=0.700), and then 21 cases were divided into low-AcBc (n=13) and high-AcBc (n=8) groups. In contrast to low-AcBc cases, high-AcBc recipients had 1/ suppressed CC3 (p=0.0426) and CC8 (p=0.0298) ; 2/ decreased sAST (374.9±110.0 vs 443.6±182.3 IU/L) and T-Bil (3.8±0.9 vs 7.4±1.5 mg/dL) levels at POD1; 3/ lower incidence of EAD (0.0 vs 23.1%); 4/ shorter post-LT ICU stay (15.1±3.0 vs 27.2±9.3); and 5/ better overall graft survival (3-y: 100.0 vs 64.1%, p=0.0647) and rejection-free graft survival (3-y: 90.0 vs 64.1%).

*Conclusions: This study demonstrated that hepatic AcBc was associated with depressed pro-apoptotic molecule profile, suppressed innate/adaptive immune reactions and preferable LT outcomes. Hence, β-catenin activation is not only a potential biomarker but may also serve as a therapeutic target to ameliorate IRI in LT recipients.

« Back to 2019 American Transplant Congress