Annual Meeting of the North American Society for Pediatric Gastroenterology and Nutrition; Orlando, October 22-24, 1998
IN VIVO GENE TRANSFER AND EXPRESSION IN THE INTESTINE AND LIVER FOLLOWING INTRAGASTRIC INJECTION OF A RETROVIRAL VECTOR IN THE NEWBORN RAT
The intestinal epithelium is an attractive target site for somatic gene therapy. Previous studies using retroviruses as a vector, showed the transfer of a reporter gene occurs in the small intestinal epithelial cells at high efficiencies in vitro, however transduction efficiency has been low in adult animal models. Adenoviruses were effective vectors but expression of the reporter gene was transient. In this study, transduction of a retroviral vector (Zenßgal) was measured in Sprague-Dawley rats intestines, liver and colon following intragastric injection in the newborn rat. The results indicate that an appropriately prepared retroviral vector can be used to efficiently transfer genetic material into the rat intestinal epithelial and that the expression is stable without any decrease in expression over an extended time period. Intestines, liver and colon were harvested at 3, 7, 30, 60 and 90 days following retroviral injection. We employed immunohistochemistry and a chemiluminecent assay to locate and quantitatively detect β-galactosidase in the intestinal tract. This study shows that following gene transfer, β-gal was efficiently transferred and expressed in the intestinal epithelium of the rat, as indicated by all of the villous enterocytes being positive by histochemistry. The transgene product, as indicated by β-galactosidase activity, was also increased by the chemiluminecent assay than that of the control intestinal tissue from 30 days through 90 days following injection, both 60 days and 90 days were significantly higher. This is in contrast to liver which only had a significant increase at 7 days following injection. These findings demonstrated that a retroviral vector is an effective method of gene transfer into intestinal enterocytes in the newborn rat. Using this technique stem cells must be transduced in order to achieve such long term expression. These results offer great promise to the use of the intestine as a site for gene therapy application In utero as well as in the neonate for treatment of many metabolic diseases as well as diseases caused by a deficiency in protein expression.
This work was supported by the NASPGN young investigator award.
PLENARY SESSION I© 1998 Lippincott Williams & Wilkins, Inc.