Background: The transcription factor nuclear factor-kappaB (NF-kappaB) plays a pivotal role in inflammatory responses by upregulating mRNA expression of, for example, proinflammatory cytokines and chemokines. Although in vitro studies have shown that Helicobacter pylori can induce NF-kappaB activation in gastric cancer cell lines, there is little information on cellular localization of NF-kappaB in H. pylori-infected gastric mucosa.
Methods: H. pylori-infected and -negative patients with various endoscopic findings were examined. NF-kappaB expression was studied by means of Southwestern histochemistry, a new method of localizing transcription factors. Labeled double-stranded oligo-DNA with specific consensus sequence for the NF-kappaB binding site was reacted with frozen sections from gastric biopsy specimens. We compared mucosal interleukin-8 (IL-8) and IL-1beta levels as measured with enzyme-linked immunosorbent assay with the degree of NF-kappaB expression.
Results: NF-kappaB expression was often evident in nuclei of epithelial cells in H. pylori-infected gastric mucosa. The degree of NF-kappaB expression on the epithelium was significantly more severe in H. pylori-infected than in -negative mucosa. The degree of NF-kappaB expression also correlated with mucosal IL-8 levels but not with IL-8.
Conclusions: H. pylori infection increases the expression of NF-kappaB in gastric mucosa, suggesting that NF-kappaB is involved in inflammatory responses to H. pylori.