In this study, we investigated the promoter DNA methylation (DNAm) status of the MMP-9 and TIMP-1 genes in patients with chronic periodontitis to evaluate disease progression. Using pyrosequencing technology, DNAm levels of MMP-9 and TIMP-1 CpG islands were measured in 88 chronic periodontitis patients and 15 healthy controls. We found a positive correlation between methylation levels of MMP-9 CpG islands and the severity of chronic periodontitis. Methylated CpG islands were also closely associated with the duration of chronic periodontitis. Moreover, female patients exhibited lower methylation levels of MMP-9 but higher methylation levels of TIMP-1 compared with male patients, and the methylation levels of TIMP-1 gradually decreased with age. The findings of gender disparity in the DNAm of MMP-9 and TIMP-1 genes provide novel insights into chronic periodontitis.
Keywords: MMP; TIMP-1; collagen balance; methylation; periodontitis.