Phagocytosis and adhesiveness of peripheral blood polymorphonuclear leukocytes in patients with rapidly progressive periodontitis

A potential role of an intracellular signaling defect in neutrophil functional abnormalities and promotion of tissue damage in patients with localized juvenile periodontitis

Localized juvenile periodontitis is a destructive form of periodontal inflammatory disease which has its onset at puberty. The etiopathology of the disease is still unclear but neutrophils have been suggested to play a major role both in the production and development of the disorder. About 70% of the patients with localized juvenile periodontitis exhibit neutrophil functional abnormalities, such as decreased chemotaxis and phagocytosis. Interestingly, it has been frequently reported that the same hypoactive cells show an enhanced respiratory burst response and increased adhesion. Several possible mechanisms explaining neutrophil anomalies in localized juvenile periodontitis have been proposed. These include the presence of soluble serum factors capable of modulating neutrophil function, altered cell-surface receptor expression and/or function, and a change in the post-receptor signaling events. Recently, a growing evidence has accumulated showing that the diacylglycerol metabolism could be altered in neutrophils from patients with localized juvenile periodontitis. This change, which may be due to a defect in a major diacylglycerol metabolizing enzyme, diacylglycerol kinase, results in enhanced accumulation of diacylglycerol in activated cells. Because diacylglycerol is an endogenous activator of protein kinase C, the increased and prolonged generation of diacylglycerol could lead to abnormal pattern of protein kinase C-regulated neutrophil functions, explaining the parallel hypo- and hyperactivities.

Psychosocial factors and adult onset rapidly progressive periodontitis

On the basis of clinical observations, some periodontologists have suggested an association between psychosocial factors such as depression, stress and anxiety, and adult onset rapidly progressive periodontitis (RPP). This study investigated more formally possible associations between a number of relevant psychosocial factors and RPP. The significance of the psychosocial variables was assessed by comparing 3 groups: 50 patients with RPP, 50 patients with routine chronic adult periodontitis (RCAP), and 50 patients without significant periodontal destruction (controls). It was anticipated that the RPP group would show higher levels of psychosocial maladjustment than the RCAP and control groups. A between-subjects multivariate analysis of covariance indicated that the combined psychosocial variables were significantly related to the periodontal diagnosis. 2 psychosocial factors, depression and loneliness, were significant in distinguishing between groups. The RPP group presented significantly increased depression and loneliness compared to the RCAP and control groups. Future research is indicated to further clarify the significance of these psychosocial differences in relation to the onset and progression of RPP.

Action of sodium fluoride on phagocytosis by systemic polymorphonuclear leucocytes

Alterations in phagocytosis appear to be important in the onset and development of periodontitis. We investigated new substances that may be of use in the treatment of periodontitis. In a preliminary study, we tested the effect of sodium fluoride on phagocytosis by circulating polymorphonuclear leucocytes (PMNs) in 10 replicate assays using blood from six healthy subjects. Sodium fluoride was tested at concentrations of 1.0 micron to 4.0 microns against Streptococcus oralis, Streptococcus mutans, Streptococcus sobrinus and Streptococcus sanguis. The phagocytic index against all microorganisms increased significantly at all concentrations of sodium fluoride assayed; this effect was dose dependent. Sodium fluoride appeared to stimulate phagocytosis via two mechanisms: an apparent increase in bacterial susceptibility to phagocytosis, and direct stimulation of phagocytosis by PMNs.

Chemoluminescence generation and MTT dye reduction by polymorphonuclear leukocytes from periodontal disease patients

Alterations of polymorphonuclear leukocytes (PMNs) functions have been reported in patients with severe forms of some periodontal disease. In this study we evaluated the chemoluminescence generation and MTT dye reduction by human PMN in patients with juvenile periodontitis (JP), rapidly progressive periodontitis (RPP) and adult periodontitis (AP) during protein kinase C (PKC) activation or during the phagocytosis of opsonized zymosan. The results demonstrated that only PMNs of JP patients showed a decreased chemoluminescence generation and MTT dye reduction during the phagocytosis of opsonized zymosan (p < 0.05). The time to reach the maximal peak during the PKC activation on the chemoluminescence reaction was evaluated and JP PMNs patients demonstrated a depressed value (7.0 +/- 0.4 min) compared with healthy volunteers (13.8 +/- 0.5 min). The etiology and importance of such cellular alterations in the immunopathogenesis of the periodontal disease are discussed.