Free and microencapsulated hepatocytes in an alginate-polylysine-alginate artificial membrane (APA), were implanted intraperitoneally into the Gunn rat, the animal model for Crigler-Najjar syndrome, to reduce serum bilirubin level. Hepatocytes from guinea pigs, Wistar and Sprague-Dawley rats whether free or microencapsulated were equally effective in lowering serum bilirubin levels in the Gunn rat. Buffalo rat hepatocytes however, were immunorejected unless microencapsulated. Decrease in serum bilirubin was concomitant with the appearance of conjugated bilirubin in the bile of Gunn rats as demonstrated by HPLC analysis. Microcapsules containing guinea pig hepatocytes showed less fibrosis than microcapsules containing hepatocytes from different strains of rats and empty microcapsules. In the Gunn rat there is significant accumulation of bilirubin in various tissues which affects the net removal of bilirubin upon implantation of the encapsulated hepatocytes. This deposition increases with time and it is organ-dependent. The kinetic data of UDP-glucuronosyltransferase (UDPGT) indicated that it is a multisubunit enzyme in which there is cooperative binding of the substrate to the subunits. The binding of bilirubin showed positive cooperativity while the binding of UDPGA exhibited kinetics with mixed cooperativity. Encapsulated hepatocytes when incubated with bilirubin and UDP-glucuronic acid can form bilirubin conjugates. This was shown by HPLC analysis.The comparison of UDPGT activity between liver homogenate, intact hepatocytes and encapsulated hepatocytes showed that there is mass transfer resistance of the APA membrane.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.28427 |
| Date | January 1994 |
| Creators | Bruni, Silvia |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001413362, proquestno: NN00081, Theses scanned by UMI/ProQuest. |
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