SNPs associated with preterm birth and periodontal disease

Objectives: Although recent studies suggest the association between maternal periodontal disease and the risk of preterm birth, conclusions are not consistent between authors. Bacteria and their lipopolysaccharides (LPS) in periodontal pockets cause local inflammatory cell responses and cytokine cascades in gingival tissue. LPS, bacteria and released proinflammatory cytokines can enter the blood stream and increase the levels of prostaglandin and cytokines which may induce preterm labour. We have previously reported SNPs (single nucleotide polymorphisms) in Fc receptors and cytokines associated with periodontitis. In this study, we analyzed the maternal SNPs in immunoregulatory genes which could link between maternal periodontal disease and preterm birth.

Methods: Genomic DNA was isolated from venous blood obtained from woman referred to the Department of Gynecology of Niigata University Medical and Dental Hospital (term birth: 71, preterm birth: 51). The following SNPs were determined with Invader Assay: FcγRIIA-131R/H, FcγRIIB-232I/T, FcγRIIIA-158V/F, FcγRIIIB-NA1/NA2, FcαR 324A/G, FcαR 56T/C, TNFRI -383A/C, TNFRII+587T/G, +694G/A, IL-1α+4845G/T, IL-1β-31C/T, +3954C/T, IL-1RA+2018T/C, TNFα-863C/A, -857C/T, IL-6-572G/C, IL-2-330T/G, IL-4-590C/T, -34C/T, IL-10-1087G/A, -824C/T. Within 5 days after labour, clinical periodontal parameters were evaluated and the presence and quantity of Porphyromonas gingivalis from subgingival plaque were determined using real-time PCR. Results: The association between preterm birth and any SNPs were not statistically significant. Clinical variables of periodontal disease were significantly different between genotypes of FcγRIIA-131R/H, FcγRIIIB-NA1/NA2, and IL-1α+4845G/T. Positive subjects with Porphyromonas gingivalis in subgingival plaque, TNFα-863C/A polymorphism was associated with preterm birth (P=0.04). Conclusions: Maternal periodontitis and/or the presence of Porphyromonas gingivalis in subgingival plaque do not necessarily cause preterm labour. TNFα-863C/A genotype might be a more specific risk marker of preterm labour for pregnant woman with Porphyromonas gingivalis .