Hwt. Matthew et al., EFFECTS OF PLASMA EXPOSURE ON CULTURED-HEPATOCYTES - IMPLICATIONS FORBIOARTIFICIAL LIVER SUPPORT, Biotechnology and bioengineering, 51(1), 1996, pp. 100-111
In order to examine their potential for use in a bioartificial liver,
hepatocytes maintained in a collagen sandwich configuration were cultu
red for 9 days in heparinized rat plasma. The cells exhibited a progre
ssive accumulation of cytoplasmic lipid droplets which proved to be ma
inly triglyceride (TG). The rate of TG accumulation correlated with th
e free fatty acid (FFA) content of the plasma. Removal of FFA and TG f
rom plasma by ether extraction significantly reduced the rate and exte
nt of TG accumulation. A smaller reduction in the rate and extent of T
G accumulation was observed when cells were maintained in an oxygen en
riched environment. The lipid accumulation suppressed urea synthesis,
but clearance of the drug diazepam, although constitutively depressed
in plasma, appeared unaffected by the accumulation. The functional and
morphological effects of plasma exposure could be fully reversed afte
r at least 6 days of plasma exposure by returning the cells to culture
medium. The results indicate that elevated FFA in plasma induces lipi
d accumulation, which inhibits urea synthesis in cultured hepatocytes.
This suggests that estimates of the cell number needed for effective
liver support should not be based upon function measurements conducted
in culture media. Furthermore, optimization of bioartificial liver su
pport device use may have to be governed by the need to limit the plas
ma exposure of cultured hepatocytes. However, the highly responsive na
ture of these cultures and the reversibility of the plasma effects sug
gest that the collagen sandwich culture system is a promising foundati
on for the development of an effective bioartificial liver support sys
tem. (C) 1996 John Wiley & Sons, Inc.