| 0561 Purified Ceramides of Porphyromonas gingivalis Induce Apoptosis in Endothelial Cells | ||
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J. ZAHLTEN1, B. RIEP1, C. WALTER2, B. SCHMECK1, M. KRÜLL1, P. N'GUESSAN1, S. HIPPENSTIEL1, F. NICHOLS3, N. SUTTORP1, and J.-P. BERNIMOULIN1, 1 Charité - University Medicine, Berlin, Germany, 2 University Basel, CH-Basel, Switzerland, 3 University of Connecticut, Farmington, USA Objectives: Porphyromonas gingivalis ceramides are found in lipid extracts of calculus-contaminated tooth roots, diseased gingival tissues and artherosclerotic plaques in humans. At least two classes of ceramides recovered from P. gingivalis have been shown to promote inflammatory secretory responses in gingival fibroblasts and peripheral blood monocytes. This indicates that P. gingivalis lipids may affect not only local periodontal disease progression, but also may impact on inflammatory systemic disease. Little is known about the effects of P. gingivalis ceramides on the vascular system and the relationship between lipid contamination of periodontal vascular tissues and the expression of inflammatory periodontal disease. In this study, we investigated whether total lipid extract or specific ceramide fractions of P. gingivalis lipids induce endothelial apoptosis or necrosis. Methods: Freshly isolated human umbilical vein endothelial cells (HUVEC) were stimulated with extracted lipids and HPLC-purified ceramide fractions of P.gingivalis (ATTC33277). Apoptosis and necrosis were assessed with microscopy using the rh Annexin V/FITC Kit (Bender MedSystemsTM), and with Cell death detection ELISA and LDH ELISA (Roche®). Results: Specific ceramide lipid fractions of P. gingivalis induced either apoptotic or necrotic death of HUVEC. Visible changes in cell-morphology appeared 2h after stimulation of cells with 10 µg/ml of the total lipid extract or 1µg/ml of the fractionated ceramides, which corresponds to ~108cfu/ml. In addition, we observed that phosphatidylserine was externalized as an early sign of apoptosis. Furthermore, we observed increased LDH release into culture medium and massive DNA fragmentation as detected by nucleosome ELISA. Conclusion: The present study shows that specific ceramide fractions of P. gingivalis lipids induce either apoptosis or necrosis of HUVEC. These data suggest that P. gingivalis ceramides could play a role as virulence factors in periodontal disease progression and may also participate in the expression of inflammatory systemic disease. (Supported by DFG grant GRK 325/3) | ||
| Seq #55 - Microbiology/ Immunology and Infection Control 4:00 PM-5:30 PM, Saturday, 28 August 2004 Crowne Plaza Hotel AVSA II | ||
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