Levels of cytokines and collagen type I and type III as a function of age in human gingivitis.

The objective of this study was to examine the age-dependent relationships between levels of inflammatory cytokines and collagen in human gingival inflammation. The gingival biopsies were obtained from 142 patients, divided into the following age groups: 6 to 14 years (prepubertal children); 18 to 35 years (young adults); 36 to 54 years (mature adults); and 55 years or above. The patients were also divided according to the severity of gingivitis. The tissues were analyzed for the contents of the inflammatory cytokines interleukin (IL)-1 beta, IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) using specific ELISA kits, and interstitial collagen type I and type III using the ELISA method and specific antibodies. We found that in young adults, levels of IL-1 beta and IL-6 were significantly higher in inflamed than in non-inflamed gingiva. Total collagen in the young adults, however, was lower in inflamed than in non-inflamed gingiva. There was no significant difference in the levels of either IL-8 or TNF-alpha between inflamed and non-inflamed gingiva independent of age. No difference in the level of collagen type I between the inflamed and non-inflamed gingiva was found in any age groups. The level of collagen type III was lower in inflamed than in non-inflamed gingiva in both children and > or = 55 year group. The results indicate a disparity in the effect of age on the levels of cytokines and of collagen type I and type III in both clinically normal and inflamed gingiva.