title: Multiporous cellulose microcarrier for the development of a hybrid artificial liver using isolated hepatocytes.
abstract: BACKGROUND
  This study was aimed at developing an optimal method for immobilizing isolated hepatocytes in cellulose multiporous microcarriers (MCs) and evaluating the metabolic activity of MC-immobilized hepatocytes.
  
  
  METHODS
  Hepatocytes isolated from the livers of male Wistar rats were immobilized in collagen-coated MCs by intermittent stirring (30 rpm for 2 min per 15 min) for 180 min or accumulation methods. The accumulation method was performed by pouring aliquots of hepatocyte suspension (8 x 10(5)) and MC suspension (1 mg) in turn onto a nylon mesh (pore size: 100 micron). The metabolic activity of MC-immobilized hepatocytes in floating culture and in a newly developed bioreactor was evaluated. The metabolic activity of MC-immobilized hepatocytes in the bioreactor was also evaluated in in vitro perfusion of a hollow-fiber-based hybrid artificial liver support system.
  
  
  RESULTS
  The accumulation method immobilized 20 times more hepatocytes in collagen-coated MCs than the intermittent stirring method (P < 0.01). Morphological observation of hepatocyte-immobilized MCs revealed that many hepatocytes were immobilized deep within the MCs maintaining a spherical shape and normal microvilli on their surface. MC-immobilized hepatocytes in floating culture revealed similar NH3 metabolism and glucose synthesis to monolayer-cultured hepatocytes, and this metabolic activity was maintained during 9h of floating culture. MC-immobilized hepatocytes in a bioreactor also showed similar NH3 metabolism to monolayer-cultured hepatocytes. The NH3 metabolism of MC-immobilized hepatocytes in in vitro perfusion of a hybrid artificial liver support system was 241.5 microg/h/mg protein/m2 membrane surface.
  
  
  CONCLUSIONS
  The results of this study indicate that the accumulation method was optimal for immobilizing isolated rat hepatocytes in MCs and that MC-immobilized hepatocytes maintained their metabolic activity for a long period.
authors.affiliation: Second Department of Surgery, Asahikawa Medical College, 4-5, Nishikagura, Asahikawa, Hokkaido, 078-8510, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kino
authors.forename: M
authors.initials: M
authors.lastname: Sawa
authors.forename: S
authors.initials: S
authors.lastname: Kasai
authors.forename: M
authors.initials: M
authors.lastname: Mito
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D002482:Cellulose; D008099:Liver / Q000166:cytology* / Q000378:metabolism; D019164:Liver, Artificial; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000641:Ammonia; D002482:Cellulose