Expression of fractalkine and RANKL in human periodontal disease

Abstract

Periodontitis is a chronic inflammatory disease with the complication of bone resorption in its advanced stage. I investigated the possible involvement of two molecules, fractalkine and RANKL, in the development of periodontitis. Fractalkine is a membrane-bound chemokine with a CX₃C motif. In addition to being a chemokine, fractalkine has the properties of an adhesion molecule. Receptor activator of NF-κB ligand (RANKL), originally reported as osteoclast differentiation factor, plays a pivotal role in differentiation of osteoclast precursor cells to osteoclasts, and is considered a key molecule in the process of bone resorption. I carried out immunohistochemical studies of fractalkine and RANKL in human gingiva and in lipopolysacchride (LPS)-injected mice.
Although positive immunoreactivities to fractalkine and RANKL have been identified in submucosal vessels of both normal and inflammatory human gingiva, inflammatory gingival tissue is stained more strongly. In contrast, anti-fractalkine antibody did not stain tissues from the heart, liver or kidney of either control or LPS-injected mice.
The results suggest that fractalkine and RANKL are important molecules in the pathogenesis and progression of human periodontitis. However, they were not identified in various visceral organs under conditions of acute inflammation produced by an experimental model in mice. Shika Igaku (J Osaka Odontol Soc) 2003 Mar; 66(1): 39-47.