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Long‐term reduction of serum bilirubin levels in gunn rats by retroviral gene transfer in vivo
Author(s) -
Tada Kouji,
Chowdhury Namita Roy,
Neufeld David,
Bosma Piter J.,
Heard Michele,
Prasad Vinayaka Rao,
Chowdhury Jayanta Roy
Publication year - 1998
Publication title -
liver transplantation and surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.814
H-Index - 150
eISSN - 1527-6473
pISSN - 1074-3022
DOI - 10.1002/lt.500040111
Subject(s) - bilirubin , unconjugated hyperbilirubinemia , medicine , endocrinology , glucuronidation , glucuronosyltransferase , gallstones , biology , chemistry , biochemistry , enzyme , microsome
Abstract Conjugation with glucuronic acid, mediated by bilirubin‐uridinediphosphoglucuronate glucuronosyltransferase (bilirubin‐UGT), is essential for efficient biliary excretion of bilirubin. Inherited absence of this enzyme activity results in the potentially lethal Crigler‐Najjar syndrome type I in humans and lifelong hyperbilirubinemia in Gunn rats. To develop a gene therapy for bilirubin‐UGT deficiency, we constructed a high‐titer replication‐deficient amphotropic recombinant retrovirus (MFG‐S hB‐UGT 1 ) capable of transferring the gene encoding bilirubin‐UGT 1 the principal bilirubin‐UGT isoform in human liver. To stimulate hepatocyte proliferation, Gunn rats were subjected to 66% hepatectomy. After 24 hours, the portal vein, the hepatic artery, and the inferior vena cava above and below the hepatic vein were clamped, and the portal vein and the isolated segment of the vena cava were cannulated. The liver was perfused with the MFG‐S hB‐UGT 1 preparation through the portal vein at 5 ml/min for 10 minutes, then circulation was restored. Control rat livers were perfused with a recombinant retrovirus expressing Escherichia coli β‐galactosidase. In MFG‐S hB‐UGT 1 –perfused rats, but not in controls, expression of human bilirubin‐UGT 1 was shown by immunotransblotting, bilirubin‐UGT assay of liver homogenates, and biliary excretion of bilirubin diglucuronide and monoglucuronide. Mean serum bilirubin levels decreased by 20% to 25% in 3 weeks and remained at that level throughout the study period (18 months). This is the first report of long‐term amelioration of inherited jaundice by retrovirus‐directed gene therapy in an animal model for Crigler‐Najjar syndrome.