Increased expression of keratinocyte growth factor messenger RNA associated with inflammatory bowel disease

Abstract

Background and Aims: Alterations in intestinal epithelial cell function are common in inflammatory bowel disease (IBD). Keratinocyte growth factor (KGF) is an epithelial cell-specific mitogen. The aim of this study was to examine IBD tissue for altered KGF expression. Methods: Expression levels of the KGF and KGF receptor transcripts were analyzed by ribonuclease protection assay. The cellular localization of each transcript was determined using in situ hybridization. Results: KGF messenger RNA levels were increased in inflamed IBD tissue in comparison with control tissues. In normal tissue, KGF messenger RNA was localized to the mesenchymal cells at the tip of the villi in the small intestine and directly underlying the mature enterocytes in the colon, whereas in IBD it was present throughout the lamina propria, although distinct from the germinal centers. The topographic distribution of the KGF in situ hybridization signal in IBD was similar to that observed for T lymphocytes. In contrast, KGF receptor transcripts were localized to the cryptal region of the mucosal epithelium in both normal and IBD tissue, with no apparent differences in the level of expression. Conclusions: The increased expression of KGF in IBD suggests that it may be involved in mediating the altered regulatory functions of intestinal epithelial cells in this disease.