06 March 2019

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Association between matrix metalloproteinase -9 and periodontitis: data from a meta-analysis

Lara Figini

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Periodontitis is a common infectious disease that can slowly damage the supporting tissue of the teeth, resulting in loss of periodontal attachment and alveolar bone. Complex biofilms on the surface of the teeth is the main reason for periodontitis. However,  social behavior and genetic factors and systemic diseases also can be related to the epidemiology of this disease. The host biofilm reaction can sometimes be excessive, with the release of matrix metalloproteinases (MMP) from the host cells and the appearance of periodontitis.
MMPs are a family of zinc-dependent endopeptidases, which are considered vital enzymes. They can degrade almost all the components of the extracellular matrix and the basal membranes. The imbalance between MMP and metalloproteinase inhibitors (TIMP) is considered to be the main reason for bone resorption in periodontitis.
The high expression of MMP can lead to increased levels of MMP in biological fluids, including serum and gingival crevicular fluid (GCF). In cases of periodontitis researchers observed elevated levels of MMP in inflammatory periodontal tissues and GCF, as well as in serum. Therefore, high levels of MMP may be a promising biomarker for periodontitis monitoring. MMP-9 is a type of MMP secreted mainly by polymorphonuclear leukocytes, which can degrade various connective tissue proteins such as type IV collagen, proteoglycans, and elastin.  

MATERIALS AND METHODS
In a meta-analysis published in JADA in 2019, the authors researched and evaluated all studies that investigated the level difference in serum and gingival levels (GCF) of the matrix metalloproteinase (MMP) -9 among patients with periodontitis and periodontally healthy  patients.
The authors searched PubMed, Embase, the Cochrane Library, and the China Biology Medicine disk databases for eligible studies in which the investigators reported the relationships between MMP-9 levels in serum and GCF and periodontitis.

RESULTS
6 case-control studies including a total of 923 healthy control participants and 557 patients with periodontitis indicated that serum MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.60; 95% CI, 0.17 to 3.03; P <.05). The results of the separate meta-analysis of the 6 case-control studies including a total of 153 healthy participants and 189 patients with periodontitis indicated that GCF MMP-9 levels were significantly higher in patients with periodontitis than in periodontally healthy control participants (SMD, 1.96, 95% CI, 0.76-3.16, P <.01). 

CONCLUSIONS
The results of this meta-analysis , which must be confirmed by other similar meta-analyzes, revealed that the levels of MMP-9 in serum and GCF in patients with periodontitis are significantly higher than those found in periodontally healthy control participants. MMP-9 levels may be considered promising biomarkers for periodontitis monitoring.
These results must be interpreted with caution because of the considerable heterogeneity among the studies included in the meta-analysis.

For additional informations: 
Meta-analysis of the association between serum and gingival crevicular fluid matrix metalloproteinase-9 and periodontitis