title: In vitro evaluation of a novel bioreactor based on an integral oxygenator and a spirally wound nonwoven polyester matrix for hepatocyte culture as small aggregates.
abstract: OBJECTIVE
  The development of custom-made bioreactors for use as a bioartificial liver (BAL) is considered to be one of the last challenges on the road to successful temporary extracorporeal liver support therapy. We devised a novel bioreactor (patent pending) which allows individual perfusion of high density cultured hepatocytes with low diffusional gradients, thereby more closely resembling the conditions in the intact liver lobuli.
  
  
  METHODS
  The bioreactor consists of a spirally wound nonwoven polyester matrix, i.e. a sheet-shaped, three-dimensional framework for hepatocyte immobilization and aggregation, and of integrated hydrophobic hollow-fiber membranes for decentralized oxygen supply and CO2 removal. Medium (plasma in vivo) was perfused through the extrafiber space and therefore in direct hepatocyte contact. Various parameters were assessed over a period of 4 days including galactose elimination, urea synthesis, lidocaine elimination, lactate/pyruvate ratios, amino acid metabolism, pH, the last day being reserved exclusively for determination of protein secretion.
  
  
  RESULTS
  Microscopic examination of the hepatocytes revealed cytoarchitectural characteristics as found in vivo. The biochemical performance of the bioreactor remained stable over the investigated period. The urea synthesizing capacity of hepatocytes in the bioreactor was twice that of hepatocytes in monolayer cultures. Flow sensitive magnetic resonance imaging (MRI) revealed that the bioreactor construction ensured medium flow through all parts of the device irrespective of its size.
  
  
  CONCLUSIONS
  The novel bioreactor showed encouraging efficiency. The device is easy to manufacture with scale-up to the liver mass required for possible short-term support of patients in hepatic failure.
authors.affiliation: Department of Experimental Internal Medicine, University of Amsterdam, Academic Medical Center, The Netherlands.
authors.forename: L M
authors.initials: LM
authors.lastname: Flendrig
authors.forename: J W
authors.initials: JW
authors.lastname: la Soe
authors.forename: G G
authors.initials: GG
authors.lastname: Jörning
authors.forename: A
authors.initials: A
authors.lastname: Steenbeek
authors.forename: O T
authors.initials: OT
authors.lastname: Karlsen
authors.forename: W M
authors.initials: WM
authors.lastname: Bovée
authors.forename: N C
authors.initials: NC
authors.lastname: Ladiges
authors.forename: A A
authors.initials: AA
authors.lastname: te Velde
authors.forename: R A
authors.initials: RA
authors.lastname: Chamuleau
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D019149:Bioreactors; D001711:Biotransformation; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D005690:Galactose / Q000378:metabolism; D008012:Lidocaine / Q000493:pharmacokinetics; D008099:Liver / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D008111:Liver Function Tests; D019164:Liver, Artificial; D008279:Magnetic Resonance Imaging; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011091:Polyesters; D013552:Swine; D013997:Time Factors; D014508:Urea / Q000378:metabolism
chemical_list: D000596:Amino Acids; D011091:Polyesters; D014508:Urea; D008012:Lidocaine; D005690:Galactose