Produzione di specie reattive dell'ossigeno, sindrome metabolica e parodontite.

Aim: Metabolic syndrome (MetS) is often associated with obesity, impaired glucose tolerance, hyperinsulinemia and diabetes. In addition, recent clinical studies have provided evidence that MetS is associated with an increased risk of periodontitis; moreover literature data showed a link between obesity and periodontitis however, the underlying mechanisms remain largely unknown. Nevertheless, it is important to note that MetS is characterized by an alteration of reactive oxygen species (ROS) metabolism with a consequent cellular dysfunction. The association between obesity and periodontal diseases could be based on the effect of pro-inflammatory cytokines released by adipose tissue. An increased caloric intake with consequent higher metabolic activity, resulting in an increased production of ROS, could also be considered. All those conditions show increased serum levels of products derived from oxidative damage, promoting a proinflammatory state. For all these reasons, in this study, we investigated if differences in ROS metabolism of phagocytes isolated from (a) patients with MetS, (b) patients with both MetS and periodontitis, (c) patients with periodontitis and (d) healthy subjects, were present. Methods: Venous blood (10 mL), obtained from each volunteers, was diluted with physiological solution (10 mL). Dextran was added in physiological solution (6%, 4 mL) to enhance the sedimentation rate of erythrocytes at 1 × g. After 30 min, the white blood cells suspension was centrifuged on Lymphoprep (Pharmacia, Sweden), according to the manufacturer’s instructions, to remove contaminating mononuclear cells, and finally the pellet underwent hypotonic lysis to remove erythrocytes. The recovered PMNs were washed three times and resuspended in Krebs Ringer phosphate (KRP) solution (200.000/mL, pH 7,4). Lympho-monocytes were isolated through Lymphoprep (Pharmacia, Sweden) density gradient centrifugation. Monocytes were then isolated from lympho-monocytes by adherence. Briefly, lympho-monocytes (1 × 106 cells/mL), resuspended in RPMI 1640 containing 2% inactivated fetal calf serum, were allowed to adhere directly to Chemiluminescence (CL) vials for 1 h at 37°C in a 5% CO2 humidified atmosphere. Non-adhered cells were then gently removed by three washes with modified KRP buffer and counted by Trypan blue exclusion test in order to calculate (by subtraction from the whole) the number of adhered cells. ROS metabolism was studied by a CL technique: the system was made up of luminol (5-amino-2,3-dihydro-1,4- phthalazindione, 100 nmol/L) and cells (1 × 105) in the presence or absence of stimulus constituted by opsonized zymosan (0.5 mg). The final volume (1.0 mL) was obtained using modified KRP buffer. ROS production was measured at 25°C for 2 h, using a LB 953 luminometer (Berthold, EG&G Co, Germany). All the experiments were performed in triplicate. All results are mean ± standard deviation (SD). The group of means were compared by analysis of variance (ANOVA), followed, when appropriate, by a multiple comparison of means by Student–Newman–Keulz test. A value of p < 0.05 was considered significant. Results: Results showed that basal ROS production (both from PMNs and from PBMs) of group A was increased respect to that obtained from group D (p <0.05). Conclusion: These results are congruent with literature data and represent a further link point between oxidative stress, MetS and periodontitis, although the actual clinical relevance of the phenomenon remains to be evaluated.