LAUSR

AIM Platelets contribute to chronic inflammation, but their role in periodontitis is not well understood. The aim of this study was to compare platelet recruitment and activation in healthy and inflamed periodontium. MATERIALS AND METHODS Gingival crevicular fluid (GCF) samples were obtained from sites of healthy periodontium, gingivitis and periodontitis. Platelets were quantified in the GCF by staining and microscopy. GCF concentrations of platelet factor 4 (PF4) [PF4]GCF and glycoprotein IIbIIIa ([GPIIbIIIa]GCF ) were determined by ELISA. Blood samples were obtained from the three patient groups. Platelets were isolated from whole blood and stimulated with lipopolysaccharide (LPS) from Porphyromonas gingivalis to evaluate and compare the LPS-induced PF4 release. RESULTS Compared to controls, platelet recruitment was increased at gingivitis and periodontitis sites, based on platelet counts and [GPIIbIIIa]GCF . [PF4]GCF was elevated in periodontal pockets but not at gingivitis or healthy sites. Circulating plasma levels of PF4 were higher in patients with generalized severe periodontitis (SP), compared to patients with gingivitis or healthy periodontium. Platelets isolated from SP patients contained and released more PF4 in response to P. gingivalis LPS than platelets from gingivitis or periodontally healthy patients. CONCLUSIONS Periodontitis is associated with increased platelet activation and PF4 release, both locally and systemically.