The Feasibility And Mechanism Research Of Associating Liver Partition And Portal Vein Ligation For Staged Hepatectomy(ALPPS)-derived Regeneration In Liver With Fibrosis

Background:liver malignancy is one of the most life-threatening diseases worldwide,and surgical resection remains the radical treatment.Postoperative liver failure due to insufficient future liver remnant(FLR)is the main cause of death.Associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)can induce rapid proliferation of FLR,thereby increases the rate of resection.However,a majority of ALPPS procedure is performed in patients diagnosed as colorectal cancer with liver metastasis,which presents no potential liver parenchymal disease.Given the capacity of regeneration is impaired in liver with fibrosis,the risk of postoperative hepatic failure is therefore increasing.While there is lack of high-level evidence to support the feasibility of ALPPS in liver with fibrosis although some cases have been reported.Thus,we investigate the clinical and experimental studies to evaluate the feasibility of ALPPS in liver with fibrosis,and to explore the molecular mechanism subsequently.Methods:Retrospectively,clinical data of 12 patients who underwent ALPPS procedure in our center were collected,including general information,surgical results in ALPPS stage ? and ?,liver proliferation,pathological features and prognosis to analyze the curative effect of ALPPS in patients with hepatic fibrosis/cirrhosis.After reviewing animal models,the thioacetamide(TAA)-induced fibrosis model in rat was established and verified by histopathology.In this setting,a thioacetamide-induced fibrosis ALPPS rat model was conducted to evaluate the feasibility of ALPPS in fibrotic liver.The proliferation of FLR was compared between normal liver and fibrotic liver groups.Similarly,TAA-induced hepatic fibrosis was established in mouse.The mechanism of ALPPS-derived liver regeneration was explored in vivo and vitro.The reversible hepatic fibrosis model induced by carbon tetrachloride(CCL4)was performed to validate the molecular mechanism.Results:In clinical settings,we found that compared with the 8.8%perioperative mortality from ALPPS registry,the mortality rate of 50%in fibrotic liver was distinctly increased.At the same time,our further analysis found that in patients with hepatic fibrosis/cirrhosis,the incidence of adverse events in patients with extremely insufficient FLR(<30%)was significantly higher than that in patients with FLR between 30 to 40%.Using tourniquet instead of the traditional liver parenchymal dissection to block hepatic parenchymal communicating flow allowed the incidence of biliary leakage minimized after ALPPS stage 1.Compared with the incidence rate of bile leakage up to 40%reported by earlier studies,there was no bile leakage in our center.Compared with the portal vein ligation and sham groups,ALPPS induced the accelerated proliferation of FLR in rats with fibrotic livers(p=0.035 at day-1,p?0.059 at day-2,p?0.171 at day-5 and p<0.05 for all).However,compared with the normal liver group,the capacity of inducing rapid proliferation of FLR in the fibrotic liver was significantly decreased,which was confirmed by immunohistochemistry of Ki-67,western blotting of PCNA and Cyclin D1.In the ALPPS stage ?,there was a certain risk of death in the fibrotic liver group while no death in the normal liver group.Meanwhile,the fibrotic liver group was significantly worse than the normal liver group(p?0.005)by comparing the proliferation of FLR after stage ?.In terms of liver function assessment,the fibrotic liver group was inferior to the normal liver group both in stage ? and ?.For the molecular mechanism,we found that plenty of hepatic stellate cells(HSCs)were activated in the fibrotic liver.In the subphenotype analysis,the above-mentioned hepatic stellate cells were characterized by high expression of type ? collagen fibers and low or moderate expression of hepatic growth factor,which indicated the anti-regenerative effect of HSC with high expression of transforming growth factor ?(TGF-?).In vivo and in vitro studies,we found that high expression of TGF-? inhibited hepatocyte proliferation,promoted apoptosis,and activated compensatory autophagy.After incubated with chloroquine to inhibit autophagy,the inhibitory effect of TGF-? on hepatocyte growth was aggravated and the apoptosis increased.In the CCL4-mduced reversible fibrosis model,we found that hepatic proliferation capacity was negatively correlated with the subphenotype of stellate cells and expression of TGF-?.Inversely,autophagy levels were positively correlated with expression of TGF-?.Conclusions:In liver with fibrosis,the ALPPS-derived proliferation of FLR is feasible but attenuated.Therefore,ALPPS should be cautious in liver with fibrosis/cirrhosis,especially for patients with FLR less than 30%.Excessive activation of HSCs and high expression of TGF-? inhibits hepatic proliferation in fibrotic liver.As one of the protective mechanisms,compensatory autophagy is activated to partially compensate for the impaired proliferative potential.This discovery is expected to provide new therapeutic targets and theoretical basis for improving the safety and efficacy of ALPPS.