Assessment and improvement of liver specific function of the AMC-bioartificial liver.
The variety of methods for measuring bioactive mass and functionality of bioartificial livers (BAL) is confusing and prevents accurate comparison of reported data. Here we present a comparison of different hepatocyte quantification methods and propose that estimation of cell pellet volume after centrifugation generates a reliable, useful and fast method. In addition a correlation is made between several function tests performed in 26 bioreactors to assess their predictive value. The ammonia eliminating capacity was found to be most predictive for other liver functions, except for lidocaine elimination as a measure of mixed function oxidase activity, which should therefore be determined separately. The oxygen consumption test proved to be an easy and predictive parameter as well. The first generation of our BAL system needed further development to assure optimal treatment of acute liver failure (ALF) patients. Changes in the porcine hepatocyte isolation method and bioreactor loading as well as changes in bioreactor configuration, including use of different materials, resulted in a significantly improved level and maintenance of in vitro BAL function. A fourfold increase in ammonia eliminating capacity, which is only reduced to 75% after seven days of culturing, offers promising prospects for further clinical application.


CONCLUSIONS
The current second generation of our BAL and improvement of hepatocyte isolation and testing protocols have led to a significant increase in the level as well as the maintenance of hepatocyte specific function in our BAL. Finally, consensus on definition of the bioactive mass to be loaded in the bioreactor and insight in the variation and reliability of the functional and metabolic parameters enhances comparison of the different types of bioartificial livers presented in literature.
van de Kerkhove
M P
MP
Department of Surgery (Surgical Laboratory), Academic Medical Center, University of Amsterdam, The Netherlands. M.P.vandeKerkhove@amc.uva.nl
Poyck
P P C
PP
van Wijk
A C W A
AC
Galavotti
D
D
Hoekstra
R
R
van Gulik
T M
TM
Chamuleau
R A F M
RA
D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D019149:Bioreactors; D002452:Cell Count; D002469:Cell Separation; D002498:Centrifugation; D005260:Female; D022781:Hepatocytes / Q000166:cytology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008012:Lidocaine / Q000378:metabolism; D008111:Liver Function Tests; D019164:Liver, Artificial; D010101:Oxygen Consumption; D013552:Swine
D000641:Ammonia; D008012:Lidocaine; D007770:L-Lactate Dehydrogenase; D001219:Aspartate Aminotransferases