Association of IL-1B gene polymorphism with IL-1β levels in gingival crevicular fluid (GCF) and bacterial profile in patients with periodontitis.
Abstract: Background Inflammatory cytokines, such as interleukin-1β (IL-1β), play a crucial role in the pathogenesis of periodontal diseases. A high individual variation in the levels of IL-1β in gingival crevicular fluid (GCF) has been previously reported in patients with periodontitis that may affect the periodontal outcome. GCF IL-1β levels are possibly affected by genetic polymorphisms and/or ... read moreby the presence of periodontal pathogens. Concomitant analysis of the impact of IL-1B gene polymorphisms and specific periodontal pathogens on IL-1β levels in GCF remains to be evaluated. The goal of this study was to investigate the role of an IL-1B single-nucleotide polymorphism at position +3954 [IL-1B (3954) SNP] and the presence of eleven (11) periodontal pathogens on GCF levels of IL-1β in patients with periodontitis. Materials & Methods In this cross-sectional study, clinical periodontal parameters and biological samples were collected from non-smoking patients with periodontitis in good general health (n=32). Clinical parameters were recorded at 6 sites/tooth and included: plaque accumulation, bleeding on probing/ suppuration, pocket depth and attachment level. Third molars were excluded from analysis. DNA was extracted from buccal epithelial cells and was analyzed for the presence/absence of IL-1B (3954) gene polymorphism by polymerase chain reaction (PCR). GCF and subgingival plaque samples were collected from one healthy and one periodontitis site within the same periodontitis patient. GCF samples were used for the quantification of IL-1β levels with enzyme linked immunosorbent assay (ELISA), while plaque samples were analyzed by PCR for the detection of eleven periodontal pathogens. Statistical analysis was performed using SAS, Version 9.2 (SAS Institute, Cary, NC) and significance of difference was indicated at the level of 0.05 (p<0.05). Results The prevalence of IL-1B (3954) SNP was 40.63% in the study population. IL-1B (3954) SNP was significantly associated with higher GCF IL-1β levels in patients with periodontitis (p<0.05). Porphyromonas gingivalis, Tanarella forsythia, and Fusobacterium nucleatum were the only species that showed a higher frequency of detection in periodontitis patients with IL-1B (3954) SNP positive compared to patients with IL-1B (3954) SNP negative. No significant associations were found between the detection of any of the tested periodontal pathogens and the IL-1β levels in GCF. Conclusions Our results suggest that periodontitis patients with IL-1B (3954) SNP positive demonstrate higher GCF IL-1β levels and frequency of detection of P. gingivalis, T. forsythia, and F. nucleatum when compared to patients with IL-1B (3954) SNP negative. The increased levels of IL-1β in GCF in periodontitis patients seem to be associated more with the IL-1B genotype status rather than with the presence of several periodontal pathogens. Our data provide additional evidence and support previous studies showing that IL-1B (3954) SNP increases host susceptibility and risk to periodontitis.
Thesis (M.S.)--Tufts University, 2015.
Submitted to the Dept. of Periodontology.
Advisor: Evangelos Papathanasiou.
Committee: Charles Hawley, Theoharis Theoharides, and Jennifer Bassett-Midle.
Keyword: Dentistry.read less