1995 Fiscal Year Final Research Report Summary
Development of a new hybrid-type aftificial liver support system using packed-bed type reactor
| Project/Area Number |
05555218
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
生物・生体工学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
OHSHIMA Norio Univ.of Tsukuba, Inst.Basic Med.Sci Professor, 基礎医学系, 教授 (50015971)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Hideki Kobe Univ.Faculty of Technol.Professor, 工学部, 教授 (30263396)
MIYOSHI Hirotoshi Kaneka Co., Research Inst.Researcher, 研究員
OOKAWA Keiko Univ.of Tsukuba, Inst.Basic Med.Sci Assist.prof., 基礎医学系, 講師 (30251052)
YANAGI Kennichi Univ.of Tsukuba, Inst.Basic Med.Sci Assist.prof., 基礎医学系, 講師 (70239797)
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| Project Period (FY) |
1993 – 1995
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| Keywords | hybrid-type aftificial liver support system / high density culture / reticulated polyvinyl formal resin / packed-bed type bioreactor / hepatocyte |
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| Research Abstract |
In order to develop a hybrid-type artificial liver support system (ALSS) using cultured hepatocytes, following attempts were carried out.
1. Kinetic analyzes of the performance of a hybrid-type ALSS
To obtain sound criteria for the optimal design and improvement of the hybrid-type ALSS using isolated hepatocytes, theoretical and experimental evaluations of the performance of the ALSS were made based on the compartmental mass transfer model and reaction kinetics of the cultured hepatocytes. Results of in vitro and ex vivo perfusion experiments using a hollow-fiber type module, a rotating-disk type module or packed-bed type module indicated that experimentally obtained performance of the module in terms of hepatocyte viability and a few metabolic functions were well correlated with the theoretically estimated performances. Simulation studies related to the design problems of a full-scale device revealed that the performance of the ALSS is inevitably limited by the viability of the hepatocy
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tes. It was suggested that a considerable improvement in the performance of ALSS is to be attained by improving hepatocyte culture conditions.
2. Long-term continuous culture of hepatocytes in a packed-bed reactor utilizing porous resin
We investigated the long-term metabolic function of hepatocytes incubated in a newly developed packed-bed type reactor using reticulated polyvinyl formal (PVF) resin as a supporting material. Long-term (up to 1 week) perfusion culture experiments using the packed-bed reactor (20mm i.d.) loaded with 500 PVF resin cubes (mean pore size 250mum, 2*2*2mm), together with conventional monolayr culture experiments as controls, were performed in serum-free or serum-containing medium. Ammonium metabolism, urea synthesis and albumin secretion activities were evaluated quantitatively based on reaction kinetic analyzes as indices of metabolic functions of the cultured hepatocytes. When serum-free medium was used in the perfusion cultures, hepatocytes functions showed significant decay with elapse of the culture period, being less than 10% of those measured on day 1. This loss of activity was more prominent in the perfusion culture than in the monolayr cultures using this medium. In contrast, when serum-containing medium was used, approximately 50% of these activities obtained on day 1 were maintained even at the end of the cultures both in the perfusion and monolayr culture experiments. It was concluded that the packed-bed reactor using PVF resin enabled high-density culture of hepatocytes, and showed a satisfactory ability to maintain metabolic functions of the immobilized hepatocytes for relatively long periods of up to 1 week. This type of reactor is thus considered to represent a breakthrough in overcoming difficulties involved in the development of a hybrid type artificial liver support system. Less
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