Periodontal pathogen-related stimulation indicates unique phenotype of primary cultured human fibroblasts from gingiva and periodontal ligament: Implications for oral health disease

Statement of Problem. The fibroblast is considered an important cellular component in periodontitis because it is the predominant cell type in periodontal connective tissue. Purpose. The purpose of this study was to test whether gingival fibroblasts (GF) and periodontal ligament fibroblasts (PDLF) are heterogeneous in their production of inflammatory mediators associated with bone resorption in response to lipopolysaccharides from the gram-negative bacterium Porphyromonas gingivalis. To test this hypothesis, we (1) compared interleukin-6 production by cultured human PDLF and GF isolated from the same individual when exposed to P. gingivalis lipopolysaccharide; and (2) compared prostaglandin-E, production by cultured human PDLF and GF isolated from the same individual when exposed to P. gingivalis lipopolysaccharide. Material and Methods. Human periodontal ligament and gingival fibroblasts were cultured from biopsies and exposed to P. gingivalis lipopolysaccharide. Levels of interleukin-6 and prostaglandin-E(2) secreted into culture supernatant were measured by enzyme linked immunosorbent assay and the data analyzed. Gingival fibroblasts secreted similar interleukin-6 and elevated prostaglandin E(2) levels compared with unstimulated cells. Periodontal ligament fibroblasts secreted elevated levels of both mediators compared with unstimulated cells. Secreted levels of interleukin-6 and prostaglandin E(2) by primary gingival and periodontal ligament fibroblast cultures appear to differ when stimulated with a periodontal pathogen-related virulence factor. Conclusion. The fibroblast of the periodontal ligament and the fibroblast of the gingiva may represent different phenotypes that play unique roles in tissue responses to implants.