Matrix metalloproteinases and periodontal diseases

Periodontitis is a chronic inflammatory disorder characterized a complex interaction between periodontopathic bacteria and the host inflammatory response resulting in release of pro-inflammatory cytokines leading to the destruction of periodontal tissues and alveolar bone. One of the important host factors involved in periodontal diseases is matrix metalloproteinases (MMPs), which is responsible for collagen and extracellular matrix (ECM) degradation of the periodontal tissues. MMPs comprise a family of around 25 members broadly categorized into six groups, which are involved in various physiological and pathological conditions. The activities of MMP are generally balanced by endogenous inhibitors such as tissue inhibitors of metalloproteinase (TIMP), and any imbalance between MMP and TIMP levels plays an important role in the disease progression. Assessment of MMP in tissues, GCF, and saliva may serve as an important biomarker in diagnosis of periodontal diseases and also for prognostic follow-up. Targeted therapy aimed at reducing effects of MMP may serve as a useful adjunct for treatment of periodontitis. This review provides an overview of MMP and its role in various physiological and pathological conditions with emphasis on its association with periodontal diseases. A note on its inhibitors and therapeutic importance is also provided.