Polysialic acid/neural cell adhesion molecule modulates the formation of ductular reactions in liver injury.

UNLABELLED: In severe liver injury, ductular reactions (DRs) containing bipotential hepatic progenitor cells (HPCs) branch from the portal tract. Neural cell adhesion molecule (NCAM) marks bile ducts and DRs, but not mature hepatocytes. NCAM mediates interactions between cells and surrounding matrix; however, its role in liver development and regeneration is undefined. Polysialic acid (polySia), a unique posttranslational modifier of NCAM, is produced by the enzymes, ST8SiaII and ST8SiaIV, and weakens NCAM interactions. The role of polySia with NCAM synthesizing enzymes ST8SiaII and ST8SiaIV were examined in HPCs in vivo using the choline-deficient ethionine-supplemented and 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet models of liver injury and regeneration, in vitro using models of proliferation, differentiation, and migration, and by use of mouse models with gene defects in the polysialyltransferases (St8sia 2+/-4+/-, and St8sia2-/-4-/-). We show that, during liver development, polySia is required for the correct formation of bile ducts because gene defects in both the polysialyltransferases (St8sia2+/-4+/- and St8sia2-/-4-/- mice) caused abnormal bile duct development. In normal liver, there is minimal polySia production and few ductular NCAM+ cells. Subsequent to injury, NCAM+ cells expand and polySia is produced by DRs/HPCs through ST8SiaIV. PolySia weakens cell-cell and cell-matrix interactions, facilitating HGF-induced migration. Differentiation of HPCs to hepatocytes in vitro results in both transcriptional down-regulation of polySia and cleavage of polySia-NCAM. Cleavage of polySia by endosialidase (endoN) during liver regeneration reduces migration of DRs into parenchyma. CONCLUSION: PolySia modification of NCAM+ ductules weakens cell-cell and cell-matrix interactions, allowing DRs/HPCs to migrate for normal development and regeneration. Modulation of polySia levels may provide a therapeutic option in liver regeneration.

Superselective transarterial chemoembolization for hepatocellular carcinoma. Validation of treatment algorithm proposed by Japanese guidelines.

BACKGROUND & AIMS: Transcatheter arterial chemoembolization with lipiodol (TACE) is widely performed in patients with hepatocellular carcinoma (HCC) unsuitable for curative treatment. It has recently been recommended for patients with 2 or 3 tumors >3 cm or ≥4 tumors in a treatment algorithm proposed by Japanese guidelines. However, the best indication and appropriateness of the algorithm for TACE are still unclear. METHODS: In 4966 HCC patients who underwent TACE, survival was evaluated based on tumor number, size and liver function; and the adequacy of the algorithm for TACE was validated. Exclusion criteria were: vascular invasion, extrahepatic metastasis, and prior treatment. The mean follow up period was 1.6 years. RESULTS: The overall median and 5-year survivals were 3.3 years and 34%, respectively. Multivariate analysis revealed that Child-Pugh class, tumor number, size, alpha-fetoprotein, and des-gamma carboxy-prothrombin were independent predictors. The survival rate decreased as the tumor number (p=0.0001) and size increased (p=0.04 to p=0.0001) in all but one subgroup in both Child-Pugh-A and -B. The stratification of these patients to four treatments in the algorithm showed potential ability to discriminate survivals of the resection and ablation (non-TACE) groups from those of the TACE group in Child-Pugh-B and partially in A. CONCLUSIONS: TACE showed higher survival rates in patients with fewer tumor numbers, smaller tumor size, and better liver function. The treatment algorithm proposed by the Japanese guidelines might be appropriate to discriminate the survival of patients with non-TACE from TACE therapy.

Prospective cohort study of transarterial chemoembolization for unresectable hepatocellular carcinoma in 8510 patients.

BACKGROUND & AIMS: To elucidate the survival of the patients with unresectable hepatocellular carcinoma (HCC) who underwent transcatheter arterial lipiodol chemoembolization (TACE) and to analyze the factors affecting the survivals. METHODS: During the last 8 years, a nationwide prospective cohort study was performed in 8510 patients with unresectable HCC who underwent TACE using emulsion of lipiodol and anticancer agents followed by gelatin sponge particles as an initial treatment. Exclusion criteria were extrahepatic metastases and/or any previous treatment prior to the present TACE. The primary end point was survival. The survival rates were calculated by the Kaplan-Meier method. The multivariate analyses for the factors affecting survival were evaluated by the Cox proportional hazard model. The mean follow-up period was 1.77 years. RESULTS: For overall survival rates by TACE, median and 1-, 3-, 5-, and 7-year survivals were 34 months, 82%, 47%, 26%, and 16%, respectively. Both the degree of liver damage and the tumor-node-metastasis (TNM) system proposed by the Liver Cancer Study Group of Japan demonstrated good stratification of survivals (P = .0001). The multivariate analyses showed significant difference in degree of liver damage (P = .0001), alpha-fetoprotein value (P = .0001), maximum tumor size (P = .0001), number of lesions (P = .0001), and portal vein invasion (P = .0001). The last 3 factors could be replaced by TNM stage. The TACE-related mortality rate after the initial therapy was .5%. CONCLUSIONS: TACE showed safe therapeutic modality with a 5-year survival of 26% for unresectable HCC patients. The degrees of liver damage, TNM stage, and alpha-fetoprotein values were independent risk factors for patient survival.