Method: The study sample comprised of 120 patients divided into four groups: G1-diabetes with poor metabolic control with dyslipidemia, G2-diabetes with good metabolic control, G3-without diabetes with dyslipidemia and G4- healthy. Blood analyses were carried out for fasting plasma glucose, glycated hemoglobin (HbA1c) and lipid profile. Periodontal examination consisted of visible plaque index (VPI), gingival bleeding index (GBI), bleeding on probing (BOP), probing depth (PD), clinical attachment levels (CAL) and suppuration. Samples of gingival crevicular fluid (GCF) were collected from 4 sites without periodontal disease and 4 sites with periodontal disease. Levels of LPO were assessed by the oxidized LDL (ELISA) and the malondialdehyde – MDA (HPLC) in plasma and in GCF. Cytokines (TNF-α, IL-6, and IL-10) were evaluated by the multiplex bead technique in GCF.
Result: All periodontal parameters were worse in G1 when compared to the others groups, particularly BOP, PD≥6mm, CAL≥5mm and suppuration. Inflammatory cytokines expression in GCF and lipid peroxidation levels (MDA and ox LDL) were significantly increased in DM groups (p<0.05), especially in G1 (p<0.05). There were significant correlations between levels of MDA and the expression of GCF cytokines, especially TNF-α (r:0.41;p<0.001) suggesting that LPO can increase the odds of expression of inflammatory markers in the inflamed site. After adjusting for confounders, among those patients who have high plasmatic levels of MDA there was about 1.81 (CI 1.12-2.92), 2.0 (CI 1.25-3.23) and 1.87 (CI 1.17-2.99) fold increase in the odds of having severe BOP, PD≥6mm and CAL≥ 5mm, respectively.
Conclusion: It can be suggested that LPO may represent an important mechanism to explain the increased severity of periodontal disease in diabetic patients.