EMMPRIN Expression in Periodontal Tissues And Its Correlation With MMP-9

Objective: To observe and correlate the expression of EMMPRIN (Extracellular Matrix Metalloproteinase Inducer) and MMP-9, in periodontally inflamed and clinically healthy tissues.

Materials and Methods: A total of 36 subjects, 30 generalized moderate to severe chronic periodontitis and 6 healthy subjects participated. Two gingival biopsies were obtained from each periodontitis subject; one from a site with severe attachment loss (SAL) and another from a site with slight attachment loss (SLAL). One biopsy was obtained from each healthy control (HC) subject. Tissues obtained were processed for routine immunohistochemistry (IHC) and evaluated for the expression of EMMPRIN and its correlation with degree of inflammation. Two EMMPRIN and inflammatory scores were assigned to each periodontitis specimen; one to a relatively inflamed area (SALi, SLALi) and one to a relatively less/non-inflamed area (SALni, SLALni). Each HC specimen received one EMMPRIN and inflammatory score. After initial IHC evaluation, six specimens from the periodontitis subjects with extensive expression of EMMPRIN and inflammatory infiltrate, and all HC specimens, were further assessed for the expression of MMP-9 through similar IHC processing. Expression of MMP-9 in relation to EMMPRIN was observed by histologic evaluations. Statistical analysis was done using ANOVA and linear regression.

Results: The mean EMMPRIN scores for four groups obtained from the periodontitis patients were: SALi, 1.16; SALni, 0.94; SLALi, 1.13; and SLALni, 0.87. HC subjects showed the lowest EMMPRIN levels with a mean score of 0.76 and were significantly lower (p<0.05)than all other groups. Scores of SALni, SLALni groups were similar and were significantly lower (p<0.05) than both SALi and SLALi groups. Bleeding on probing was the only clinical parameter that significantly correlated with the EMMPRIN scores. MMP-9 expression correlated with the EMMPRIN expression when observed histologically.

Conclusion: EMMPRIN expression was positively correlated with increase in inflammatory infiltrate and expression of MMP-9 in gingival tissues.