Summary:
Periodontitis is an inflammatory disease of the supporting tissues of the
teeth. During the inflammatory response secreted substances, mediators of are
inflammation involved in the pathogenesis of periodontal tissue. These
substances are cytokines, extracellular matrix metalloproteinases and
prostaglandins. Prostaglandins are derivatives of arachidonic acid which is
metabolized by enzymes called cyclooxygenases. The matrix metalloproteinases
are proteolytic enzymes which degrade collagen and represent the major enzymes
in the destruction of connective tissue. Prostaglandins are the eicosanoids and
are derivatives of arachidonic acid. The prostaglandins properties are
vasodilation, pyrexia, increased permeability, periodontal destruction.
More especially PGE2 stimulates macrophages and fibroblasts to secrete MMPs and
has osteoclastic activity.
Genetic changes in the genes of MMPs and COX2 may affect the level of
transcription and protein production. Several studies and meta-analyzes
indicate that there is statistically significant association of polymorphisms
of COX- 2 and MMP9 with chronic periodontal disease .The purpose of this thesis
is to determine whether COX-2 polymorphisms -1195G /A , COX-2 -8473C / T and
MMP-9 -1562C / T appear with different frequencies in patients with chronic and
aggressive periodontitis compared to healthy ones. RFLP PCR was used in order
to identify if each individual was carrying the polymorphisms or not. This
study found no significant association between chronic periodontitis and
polymorphisms COX-2 -1195G / A, COX-2 -8473C / T and MMP-9 -1562C / T.
Correlation was not found among these polymorphisms and aggressive
periodontitis. Finally, the haplotype analysis between polymorphisms in the
COX2 gene did not conclude that there is a correlation between a particular
haplotype and chronic or aggressive periodontitis. Small sample size does not
allow firm conclusions about the association or not of these polymorphisms with
chronic and aggressive periodontitis. However, the stringency of the criteria
based on which the selection of the study group was done, adds credibility to
the research as the impact of confounding factors is eliminated. Furthermore,
this study is the first attempt carried out in the Greek population for these
polymorphisms and the second on any European population. Finally, this is the
first report that investigates correlation of the COX2 -8473T/C polymorphism
with aggressive periodontitis. Further studies with a greater number of samples
will help to validate these results.
Keywords:
COX-2, MMP-9, Polymorphism, Chronic periodontitis, Aggressive periodontitis
