Time filter

Source Type

Seoul, South Korea

Lee J.-H.,Samsung | Lee D.-H.,Lifeliver Co Ltd | Park J.-K.,Dongguk University | Kim S.-K.,Pukyong National University | And 2 more authors.
Transplantation Proceedings | Year: 2012

The development of bioartificial liver (BAL) systems has required detailed information about the functional capabilities of cultured hepatocytes during blood or plasma passage. In this study we investigated the effects of porcine plasma and various supplements on the viability and function of adult rat hepatocytes in vitro. Primary rat hepatocytes cultured in porcine plasma supplemented with various substances showed albumin synthesis rates and viability equal to or higher than those of controls. Supplementation with calcium chloride, magnesium sulfate, trace elements, amino acids, insulin, and epidermal growth factor were essential to maintain viability and high albumin synthesis. Especially, trace elements showed significantly higher and longer albumin secretion. Isolated rat hepatocytes were cultured in Spinner flasks for 24 hours to form spheroids that were harvested and encapsulated with chitosan-alginate solution before transfer to the bioreactor in the BAL system. Encapsulated rat hepatocyte spheroids cultured with porcine plasma including trace elements showed higher viability (57%) than controls (40%) after 24 hours, with ammonia removal values of 30.92 μg/10 6 cells versus the control 9.04 μg/10 6 cells. After 24 hours of operation the urea secretion value of encapsulated rat hepatocyte spheroids cultured in porcine plasma in the presence versus absence of trace elements was 76.73 μg/10 6 cells and 18.80 μg/10 6 cells, respectively. We concluded that encapsulated hepatocyte spheroids in a packed-bed bioreactor operated with human plasma including trace elements enhanced cell viability and liver function as a bases for an in vivo clinical trial of the BAL system. © 2012 Elsevier Inc. Source

Lee J.-H.,Samsung | Lee J.-H.,Dongseo University | Jung D.-H.,Dongguk University | Lee D.-H.,Lifeliver Co Ltd | And 2 more authors.
Transplantation Proceedings | Year: 2012

Hepatocyte transplantation is a potential alternative to whole organ liver transplantation. To realize this procedure, a hepatocyte bank system capable of supplying large numbers of hepatocytes must be established. The aim of this study was to develop a cryopreservation protocol using controlled rate freezers (CRF) for the application of a bioartificial system of porcine hepatocytes. Hepatocytes were harvested from 3- to 4-week-old male pigs weighing 11-14 kg. Liver cell preparations were prepared and the spheroid hepatocytes were cryopreserved using University of Wisconsin (UW) solution in controlled freezing. After thawing, viability, plating efficiency, urea synthesis, and ammonia removal were measured to assess the effects of freezing methods. Freezing methods had effects on the viability and specific functions of hepatocytes after thawing. About 80% of the cell viability could be obtained with an optimal computer programming method (-1°C slow cooling rate with shock cooling, using UW solution with 15% dimethyl sulfoxide [DMSO]). The cryopreservation method for hepatocytes was significantly improved by using the above cryopreservation conditions. However, research on application to large-scale cryopreservation is needed for practical use. © 2012 Elsevier Inc. Source

Lee J.-H.,Samsung | Lee D.-H.,Lifeliver Co Ltd | Park J.-K.,Dongguk University | Kim S.-K.,Pukyong National University | And 2 more authors.
Transplantation Proceedings | Year: 2012

Various extracorporeal bioartificial liver (BAL) systems have been developed. To treat fulminant hepatic failure (FHF) patients. Direct cell-cell interaction is one of the major factors influencing the functions of cultured hepatocytes, which increase with progressing of cell aggregation in this study, we investigated the effects of plasma viability and function single and spheroid pig hepatocytes in vitro. Hepatocytes were cultured as spheroids by suspension culture in spinner flasks. We obtained pig plasma from animals in hepatic failure. Immobilized single pig hepatocytes exposed to the toxic pig plasma lost viability and liver function. However, immobilized pig hepatocyte spheroids showed stable ammonia removal functions and urea synthesis and lower lactate dehydrogenase, glutamine oxaloacetate transaminase, and glutamine pyruvate transminase levels during BAL operation. At 5 hours, the ammonia concentration in plasma decreased to 370 and 150 μg/dL by immobilized single and spheroid hepatocytes, respectively, the concentrations at which they were maintained thereafter. The urea concentrations in plasma were 44 versus 72 μg/dL in immobilized single versus spheroid hepatocytes respectively, at 5 hours of operation. Spheroid hepatocytes not only showed in vivo structure, but also maintained high levels of liver-specific functions. The spheroid-based BAL system may be a good candidate to treat FHF patients. © 2012 Elsevier Inc. Source

Lee J.-H.,Samsung | Park H.-J.,Samsung | Jang I.K.,Lifeliver Co Ltd | Kim H.-E.,Lifeliver Co Ltd | And 4 more authors.
Transplantation Proceedings | Year: 2014

Liver transplantation is severely limited by donor shortage although it is the only effective treatment for end-stage liver disease. So the best alternative is hepatocyte transplantation. For obtaining human hepatocytes, some stem cells originating from extrahepatic or intraheptic tissues have been isolated and characterized. Previously we have reported that human liver-derived stem cells (HLSCs) could be isolated and expanded from donated livers unsuitable for transplantation; they expressed some markers of mesenchymal stem cells but neither hematopoietic nor oval cells. In this study, we isolated and expanded HLSCs with mesenchymal characteristics from another adult human liver. They showed mesenchymal morphology and grew well under serum condition similar to our previous reports. Also, they expressed some markers of mesenchymal stem cells, such as CD44, CD73, CD90, and CD105, through fluorescence-activated cell sorting analysis. When HLSCs were sequentially exposed to fibroblast growth factor-1 (FGF-1), FGF-4, and hepatocyte growth factor (HGF) followed by FGF-4, HGF, oncostatin M, and dexamethasone, they became round or polygonal, and expressed some hepatic markers such as albumin and α1-antitrypsin in the gene or protein level. Also, they showed urea synthesis activity 7 days after treatment of FGF-4, HGF, oncostatin M, and dexamethasone. These results provided that HLSCs would be a useful cell source in the field of regenerative medicine as well as liver cell biology. © 2014 by Elsevier Inc. All rights reserved. Source

Eom Y.W.,Yonsei University | Eom Y.W.,Lifeliver Co Ltd | Lee J.E.,Lifeliver Co Ltd | Yang M.S.,Lifeliver Co Ltd | And 9 more authors.
Biochemical and Biophysical Research Communications | Year: 2011

Stem cell therapy for muscular dystrophies requires stem cells that are able to participate in the formation of new muscle fibers. However, the differentiation steps that are the most critical for this process are not clear. We investigated the myogenic phases of human adipose tissue-derived stem cells (hASCs) step by step and the capability of myotube formation according to the differentiation phase by cellular fusion with mouse myoblast C2C12 cells. In hASCs treated with 5-azacytidine and fibroblast growth factor-2 (FGF-2) for 1. day, the early differentiation step to express MyoD and myogenin was induced by FGF-2 treatment for 6. days. Dystrophin and myosin heavy chain (MyHC) expression was induced by hASC conditioned medium in the late differentiation step. Myotubes were observed only in hASCs undergoing the late differentiation step by cellular fusion with C2C12 cells. In contrast, hASCs that were normal or in the early stage were not involved in myotube formation. Our results indicate that stem cells expressing dystrophin and MyHC are more suitable for myotube formation by co-culture with myoblasts than normal or early differentiated stem cells expressing MyoD and myogenin. © 2011 Elsevier Inc. Source

Discover hidden collaborations