Gingival crevicular fluid inflammatory mediators and bacteriology of gingivitis in nonhuman primates related to susceptibility to periodontitis

The hypothesis to be tested was that the microbiota and resulting local hos t inflammatory response characteristics in oral conditions of high levels o f chronic gingival inflammation increases susceptibility to progressing per iodontitis. This study used cynomolgus monkeys, Macaca fascicularis (nonhum an primates), with high and low levels of long-standing gingival inflammati on to define the profiles of gingival crevicular fluid mediators, cytokines and immunoglobulins; describe the subgingival microbiota; and evaluate the ir susceptibility to ligature-induced periodontitis. Sixteen nonhuman prima tes were stratified into two groups (HI, LO) based upon Bleeding Index as a measure of the natural level of inflammation (HI = 1.26+/-0.45; LO=0.22+/- 0.16). The host mediator levels, subgingival microbiota, and clinical chara cteristics of the LO and HI groups were compared after 30 days of oral hygi ene, during a 30 day experimental gingivitis (7, 14, and 30 days), and duri ng periodontitis (30, 60, and 90 days). The results demonstrated that nonhu man primates with high levels of long-standing gingival inflammation when c ompared to those nonhuman primates with low inflammation show: 1) different inflammatory mediator profiles in gingival crevicular fluid (particularly for immunoglobulin A (IgA) and IgG levels), 2) a different quantitative and qualitative subgingival microbiota; and 3) a similar progression of period ontitis. Thus, while variations in host inflammatory responses to local fac tors exist in the nonhuman primates, an extensive subgingival challenge (su ch as ligation) may negate these individual differences.