Hepatocytes derived from human embryonic stem cells (hESCs) are a potential cell source for regenerative medicine. However, the definitive factors that are responsible for hepatic differentiation of hESCs remain unclear. We aimed to evaluate the effects of various extracellular matrixes and growth factors on endodermal differentiation and to optimize the culture conditions to induce hepatic differentiation of hESCs. The transgene vector that contained enhanced green fluorescent protein (EGFP) under the control of human α-fetoprotein (AFP) enhancer/promoter was transfected into hESC lines. The transgenic hESCs were cultured on extracellular matrixes (collagen type I, laminin, and Matrigel) in the presence or absence of growth factors including hepatocyte growth factor (HGF), bone morphogenetic protein 4, fibroblast growth factor 4, all-trans-retinoic acid, and activin A. The expression of AFP-EGFP was measured by flow cytometry. The culture on Matrigel-coated dishes with 100 ng/ml activin A showed 19.5% of EGFP-positive proportions. Moreover, the sequential addition of 100 ng/ml activin A and 20 ng/ml HGF resulted in 21.7% and produced a higher yield of EGFP-positive cells than the group stimulated by activin A alone. RT-PCR and immunocytochemical staining revealed these EGFP-positive cells to differentiate into mesendoderm-like cells by use of activin A and then into hepatic endoderm cells by use of HGF. Two other hESC lines also differentiated into endoderm on the hepatic lineage by our method. In conclusion, we therefore found this protocol to effectively differentiate multiple hESC lines to early hepatocytes using activin A and HGF on Matrigel.

Liver transplantation is currently the only curative therapy for end-stage liver failure; however, establishment of alternative treatments is required owing to the serious donor organ shortage. Here, we propose a novel model of hybrid three-dimensional artificial livers using both human induced pluripotent stem cells (hiPSCs) and a rat decellularized liver serving as a scaffold. Rat liver harvesting and decellularization were performed as reported in our previous studies. The decellularized liver scaffold was recellularized with hiPSC-derived hepatocyte-like cells (hiPSC-HLCs) through the biliary duct. The recellularized liver graft was continuously perfused with the culture medium using a pump at a flow rate of 0.5 mL/min in a standard CO2 (5%) cell incubator at 37 °C. After 48 h of continuous perfusion culture, the hiPSC-HLCs of the recellularized liver distributed into the parenchymal space. Furthermore, the recellularized liver expressed the albumin (ALB) and CYP3A4 genes, and secreted human ALB into the culture medium. Novel hybrid artificial livers using hiPSCs and rat decellularized liver scaffolds were successfully generated, which possessed human hepatic functions.

PURPOSE: Durable partial response (PR) and durable stable disease (SD) are often seen in patients with hepatocellular carcinoma (HCC) receiving atezolizumab plus bevacizumab (atezo-bev). This study investigates the outcome of these patients and the histopathology of the residual tumors. PATIENTS AND METHODS: The IMbrave150 study's atezo-bev group was analyzed. PR or SD per RECIST v1.1 lasting more than 6 months was defined as durable. For histologic analysis, a comparable real-world group of patients from Japan and Taiwan who had undergone resection of residual tumors after atezo-bev was investigated. RESULTS: In the IMbrave150 study, 56 (77.8%) of the 72 PRs and 41 (28.5%) of the 144 SDs were considered durable. The median overall survival was not estimable for patients with durable PR and 23.7 months for those with durable SD. The median progression-free survival was 23.2 months for patients with durable PR and 13.2 months for those with durable SD. In the real-world setting, a total of 38 tumors were resected from 32 patients (23 PRs and nine SDs) receiving atezo-bev. Pathologic complete responses (PCRs) were more frequent in PR tumors than SD tumors (57.7% v 16.7%, P = .034). PCR rate correlated with time from atezo-bev initiation to resection and was 55.6% (5 of 9) for PR tumors resected beyond 8 months after starting atezo-bev, a time practically corresponding to the durable PR definition used for IMbrave150. We found no reliable radiologic features to predict PCR of the residual tumors. CONCLUSION: Durable PR patients from the atezo-bev group showed a favorable outcome, which may be partly explained by the high rate of PCR lesions. Early recognition of PCR lesions may help subsequent treatment decision.

Background: Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a primary liver carcinoma with both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) components. We examined the clinicopathological characteristics and recurrence patterns of cHCC-CCA. Because of the rarity of cHCC-CCA, its etiology, clinicopathological features, and prognosis in comparison with other primary liver carcinoma remain unknown. Its recurrence pattern and sites in particular also need to be elucidated.Methods: All patients who underwent hepatectomy for primary liver malignancies between 2005 and 2015 were retrospectively included in this study.Results: Eight hundred and ninety-four hepatectomies were performed. Nineteen cases of cHCC-CCA (2.1%) in 16 patients were enrolled. Three patients underwent re-hepatectomy. The background of hepatitis viruses and tumor marker patterns of cHCC-CCA were similar to those of HCC and dissimilar to those of intrahepatic CCA (iCCA). Biliary invasion was common in cHCC-CCA and iCCA. The 5-year overall survival values of the cHCC-CCA, HCC, and iCCA patients were 44.7%, 56.6%, and 38.5%, respectively. The 5-year recurrence-free survival values of the cHCC-CCA, HCC, and iCCA patients were 12.2%, 28.7%, and 32.9%, respectively. The liver was the most common recurrence site. Unlike HCC, however, the lymph node was the second-most common recurrence site in both cHCC-CCA and iCCA. Pathological samples of the recurrent lesions were obtained in six patients, and four had cHCC-CCA recurrence pathologically.Conclusion: cHCC-CCA had a mixture of characteristics of HCC and iCCA. Many cases of cHCC-CCA remained cHCC-CCA pathologically even after recurrence.