Ken Fukumitsu

Effects of extracellular matrixes and growth factors on the hepatic differentiation of human embryonic stem cells.

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 alpha-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.

Keratin 19, a Cancer Stem Cell Marker in Human Hepatocellular Carcinoma

Purpose: Keratin 19 (K19) is a known marker of poor prognosis and invasion in human hepatocellular carcinoma (HCC). However, the relationship between K19 and cancer stem cells (CSCs) is unclear. Here, we determined whether K19 can be used as a new CSC marker and therapeutic target in HCC. Experimental Design: HCC cell lines were transfected with a K19 promoter–driven enhanced green fluorescence protein gene. CSC characteristics, epithelial–mesenchymal transition (EMT), and TGFb/Smad signaling were examined in FACS-isolated K19+/K19− cells. K19 and TGFb receptor 1 (TGFbR1) expression in 166 consecutive human HCC surgical specimens was examined immunohistochemically. Results: FACS-isolated single K19+ cells showed self-renewal and differentiation into K19− cells, whereas single K19− cells did not produce K19+ cells. K19+ cells displayed high proliferation capacity and 5-fluorouracil resistance in vitro. Xenotransplantation into immunodeficient mice revealed that K19+ cells reproduced, differentiated into K19− cells, and generated large tumors at a high frequency in vivo. K19+ cells were found to be involved in EMT and the activation of TGFb/Smad signaling, and these properties were suppressed by K19 knockdown or treatment with a TGFbR1 inhibitor. The TGFbR1 inhibitor also showed high therapeutic effect against K19+ tumor in the mouse xenograft model. Immunohistochemistry of HCC specimens showed that compared with K19− patients, K19+ patients had significantly poorer recurrence-free survival and higher tumor TGFbR1 expression. Conclusions: K19 is a new CSC marker associated with EMT and TGFb/Smad signaling, and it would thus be a good therapeutic target for TGFbR1 inhibition. Clin Cancer Res; 21(13); 3081–91. ©2015 AACR.

In vitro hepatic maturation of human embryonic stem cells by using a mesenchymal cell line derived from murine fetal livers

Hepatocytes derived from human embryonic stem cells (hESCs) are an attractive cell source for regenerative medicine. We previously reported the differentiation of hESCs into alpha-fetoprotein (AFP)-producing endodermal cells by using extracellular matrix and growth factors. We also reported the establishment of the MLSgt20 cell line, which was derived from mesenchymal cells residing in murine fetal livers and accelerated the hepatic maturation of both murine hepatic progenitor cells and murine ESCs. In this study, hESC-derived AFP-producing cells were isolated by using a flow cytometer and co-cultured with MLSgt20 cells. The co-cultured hESC-derived AFP-producing cells had the immunocytological characteristics of hepatocytes, expressed mature hepatocyte markers (as indicated by reverse transcription and the polymerase chain reaction), and displayed higher hepatocyte functions including ammonia removal, cytochrome P450 3A4/7 activity, and the ability to produce and store glycogen. However, the MLSgt20 cells did not directly cause undifferentiated hESCs to mature into hepatocyte-like cells. The co-culture method was thus successfully shown to induce the differentiation of hESC-derived endodermal cells into functional hepatocyte-like cells.

SOX9 is a novel cancer stem cell marker surrogated by osteopontin in human hepatocellular carcinoma.

The current lack of cancer stem cell (CSC) markers that are easily evaluated by blood samples prevents the establishment of new therapeutic strategies in hepatocellular carcinoma (HCC). Herein, we examined whether sex determining region Y-box 9 (SOX9) represents a new CSC marker, and whether osteopontin (OPN) can be used as a surrogate marker of SOX9 in HCC. In HCC cell lines transfected with a SOX9 promoter-driven enhanced green fluorescence protein gene, FACS-isolated SOX9+ cells were capable of self-renewal and differentiation into SOX9− cells, and displayed high proliferation capacity in vitro. Xenotransplantation experiments revealed that SOX9+ cells reproduced, differentiated into SOX9− cells, and generated tumors at a high frequency in vivo. Moreover, SOX9+ cells were found to be involved in epithelial-mesenchymal transition (EMT) and activation of TGFb/Smad signaling. Gain/loss of function experiments showed that SOX9 regulates Wnt/beta-catenin signaling, including cyclin D1 and OPN. Immunohistochemistry of 166 HCC surgical specimens and serum OPN measurements showed that compared to SOX9− patients, SOX9+ patients had significantly poorer recurrence-free survival, stronger venous invasion, and higher serum OPN levels. In conclusion, SOX9 is a novel HCC-CSC marker regulating the Wnt/beta-catenin pathway and its downstream target, OPN. OPN is a useful surrogate marker of SOX9 in HCC.

Efficient recellularisation of decellularised whole-liver grafts using biliary tree and foetal hepatocytes

A whole-organ regeneration approach, using a decellularised xenogeneic liver as a scaffold for the construction of a transplantable liver was recently reported. Deriving suitable scaffolds was the first step towards clinical application; however, effective recellularisation remains to be achieved. This report presents a strategy for the improvement of the recellularisation process, using novel cell-seeding technique and cell source. We evaluated recellularised liver grafts repopulated through the portal vein or the biliary duct with mice adult hepatocytes or E14.5 foetal hepatocytes. More than 80% of the cells seeded through the biliary tree entered the parenchyma beyond the ductule-lining matrix barrier and distributed throughout the liver lobule. In contrast, about 20% of the cells seeded through the portal tree entered the parenchyma. The gene expression levels of foetal hepatocyte albumin, glucose 6-phosphatase, transferrin, cytokeratin 19, and gamma-glutamyl transpeptidase were increased in three-dimensional cultures in the native liver-derived scaffolds, and the activation of liver detoxification enzymes and formation of biliary duct-like structures were supported. The metabolic functions of liver grafts recellularised with different cell types were similar. These results suggest that biliary tree cell-seeding approach is promising, and that liver progenitor cells represent a good cell source candidate.

Identification of keratin19-positive cancer stem cells associating human hepatocellular carcinoma using 18F-fluorodeoxyglucose positron emission tomography.

Purpose: The current lack of tools for easy assessment of cancer stem cells (CSC) prevents the development of therapeutic strategies for hepatocellular carcinoma (HCC). We previously reported that keratin 19 (K19) is a novel HCC-CSC marker and that PET with 18F-fluorodeoxyglucose (18F-FDG) is an effective method for predicting postoperative outcome in hepatocellular carcinoma. Herein, we examined whether K19+ HCC-CSCs can be tracked using 18F-FDG-PET. Experimental Design: K19 and glucose transporter-1 (GLUT1) expression was evaluated by IHC in 98 hepatocellular carcinoma patients who underwent 18F-FDG-PET scans before primary tumor resection. Standardized uptake values (SUV) for primary tumors and tumor-to-nontumor SUV ratios (TNR) were calculated using FDG accumulation levels, and values were compared among K19+/K19− patients. Using hepatocellular carcinoma cell lines encoding with a K19 promoter–driven enhanced GFP, 18F-FDG uptake and GLUT1 expression were examined in FACS-isolated K19+/K19− cells. Results: In hepatocellular carcinoma patients, K19 expression was significantly correlated with GLUT1 expression and FDG accumulation. ROC analyses revealed that among preoperative clinical factors, TNR was the most sensitive indicator of K19 expression in hepatocellular carcinoma tumors. In hepatocellular carcinoma cells, FACS-isolated K19+ cells displayed significantly higher 18F-FDG uptake than K19− cells. Moreover, gain/loss-of-function experiments confirmed that K19 regulates 18F-FDG uptake through TGFβ/Smad signaling, including Sp1 and its downstream target GLUT1. Conclusions:18F-FDG-PET can be used to predict K19 expression in hepatocellular carcinoma and should thereby aid in the development of novel therapeutic strategies targeting K19+ HCC-CSCs. Clin Cancer Res; 23(6); 1450–60. ©2016 AACR.

Validation of Steroid-Free Immunosuppression Regimen after Liver Transplantation

C l i n M e d International Library Citation: Fukumitsu K, Hammad A, Kaido T, Ogawa K, Fujimoto Y, et al. (2015) Validation of Steroid-Free Immunosuppression Regimen after Liver Transplantation. J Clin Gastroenterol Treat 1:008 Received: October 15, 2015: Accepted: November 25, 2015: Published: November 27, 2015 Copyright:

Establishment of practical recellularized liver graft for blood perfusion using primary rat hepatocytes and liver sinusoidal endothelial cells

Tissue decellularization produces a three‐dimensional scaffold that can be used to fabricate functional liver grafts following recellularization. Inappropriate cell distribution and clotting during blood perfusion hinder the practical use of recellularized livers. Here we aimed to establish a seeding method for the optimal distribution of parenchymal and endothelial cells, and to evaluate the effect of liver sinusoidal endothelial cells (LSECs) in the decellularized liver. Primary rat hepatocytes and LSECs were seeded into decellularized whole‐liver scaffolds via the biliary duct and portal vein, respectively. Biliary duct seeding provided appropriate hepatocyte distribution into the parenchymal space, and portal vein–seeded LSECs simultaneously lined the portal lumen, thereby maintaining function and morphology. Hepatocytes co‐seeded with LSECs retained their function compared with those seeded alone. Platelet deposition was significantly decreased and hepatocyte viability was maintained in the co‐seeded group after extracorporeal blood perfusion. In conclusion, our seeding method provided optimal cell distribution into the parenchyma and vasculature according to the three‐dimensional structure of the decellularized liver. LSECs maintained hepatic function, and supported hepatocyte viability under blood perfusion in the engineered liver graft owing to their antithrombogenicity. This recellularization procedure could help produce practical liver grafts with blood perfusion.

The Protective Effect of Transplanting Liver Cells Into the Mesentery on the Rescue of Acute Liver Failure After Massive Hepatectomy.

Postoperative liver failure is one of the most critical complications following extensive hepatectomy. Although transplantation of allogeneic hepatocytes is an attractive therapy for posthepatectomy liver failure, transplanting cells via the portal veins typically causes portal vein embolization. The embolization by transplanted cells would be lethal in patients who have undergone massive hepatectomy. Thus, transplant surgeons need to select extrahepatic sites as transplant sites to prevent portal vein embolization. We aimed to investigate the mechanism of how liver cells transplanted into the mesentery protect recipient rats from acute liver failure after massive hepatectomy. We induced posthepatectomy liver failure by 90% hepatectomy in rats. Liver cells harvested from rat livers were transplanted into the mesenteries of hepatectomized rats. Twenty percent of the harvested cells, which consisted of hepatocytes and nonparenchymal cells, were transplanted into each recipient. The survival rate improved significantly in the liver cell transplantation group compared to the control group 7 days after hepatectomy (69 vs. 7%). Histological findings of the transplantation site, in vivo imaging system study findings, quantitative polymerase chain reaction assays of the transplanted cells, and serum albumin measurements of transplanted Nagase analbuminemic rats showed rapid deterioration of viable transplanted cells. Although viable transplanted cells deteriorated in the transplanted site, histological findings and an adenosine-5′-triphosphate (ATP) assay showed that the transplanted cells had a protective effect on the remaining livers. These results indicated that the paracrine effects of transplanted liver cells had therapeutic effects. The same protective effects were observed in the hepatocyte transplantation group, but not in the liver nonparenchymal cell transplantation group. Therefore, this effect on the remnant liver was mainly due to the hepatocytes among the transplanted liver cells. We demonstrated that transplanted liver cells protect the remnant liver from severe damage after massive hepatectomy.

A Propensity Score-Based Analysis of Laparoscopic Liver Resection for Liver Malignancies in Elderly Patients

ABSTRACT Purpose: Laparoscopic liver resection is safe, feasible and associated with less blood loss, shorter hospital stays and fewer postoperative complications in the working age patients with malignant liver tumors. However, it is still unclear if the elderly patients with malignant liver tumors would also benefit from that approach as the younger patients. So, the aim of the study was to compare the clinical outcomes of laparoscopic versus open liver resection for malignant liver tumors in elderly patients. Materials and Methods: Between March 2009 and July 2016, all elderly patients (≥70 years old) who underwent laparoscopic (n = 40) and open (n = 202) liver resection for malignant liver tumors were included. A one to one propensity score matching analysis was performed, based on 6 covariates, to decrease the selection bias. Results: There was no significant difference between the laparoscopic and open liver resection groups regarding the patient characteristics and tumor features. The operative time was comparable between both groups (Laparoscopic group 259 min vs Open group 308 min, p = .86), while patients who underwent laparoscopic liver resection had lower intraoperative blood loss (30 ml vs 517 ml, p < .0001), shorter hospital stays (10 days vs 23 days, p < .0001), and less overall morbidity (15% vs 38%, p = .04). The one-, three-, and five-year survival for patients with hepatocellular carcinoma was comparable between both groups (Laparoscopic group 96%, 74%, 47%, vs Open group 94%, 71%, 48%, p = .82), whereas The one-, three-, and five-year recurrence-free survival for patients with hepatocellular carcinoma was significantly higher in the laparoscopic group (88%, 60%, 60% vs 54%, 25%, 19%, p = .019). Conclusions: Laparoscopic approach for minor liver resection in elderly patients is safe and feasible with less blood loss, a shorter hospital stay, less postoperative complications and a better oncological outcome.