Novel ceramides recovered from Porphyromonas gingivalis: relationship to adult periodontitis

The primary purpose of this study was to characterize the major structural features of ceramides recovered from Porphyromonas gingivalis, a suspected periodontal pathogen, Complex lipids extracted from P. gingivalis were trea ted with N,O-bis(trimethylsilyl)-trifluoroacetamide and analyzed ming gas c hromatography-mass spectrometry, Mass spectra of lipid derivatives revealed cleavage products consistent with structures of four major ceramides, Two of the major ceramides are proposed to contain long chain bases of either 2 -amino-1,3-octadecanediol or 2-amino-1,3-nonadecanediol in amide linkage to 3-hydroxy isobranched C<INF>17:0</INF>. The remaining major ceramides are proposed to contain either 2-amino-1,3-octadecanediol or 2-amino-1,3-nonade canediol in amide linkage to C<INF>17:1</INF>. Alkaline hydrolysis of P. gi ngivalis lipids and subsequent formation of suitable derivatives revealed 3 -hydroxy isobranched C<INF>17:0</INF>, C<INF>17:1</INF>, 2-amino1,3-octadec anediol, and 2-amino-1,3-nonadecanediol as hydrolysis products. Therefore, the constitutive fatty acids and long chain bases recovered in alkaline hyd rolysis products of P. gingivalis lipids are consistent with the proposed c eramide structures. The next goal of this study was to investigate whether these bacterial ceramides exist in lipid extracts of human teeth and gingiv al tissue at sites of severe adult periodontitis. Using selected ion monito ring of characteristic ions and retention times for each ceramide described above, lipids from teeth and gingival tissue were shown to contain primari ly the ceramides containing C<INF>17:1</INF>.<SUP></SUP> It is concluded th at P. gingivalis synthesizes at least four major ceramides and two of these ceramides are selectively adsorbed to diseased tooth surfaces and may pene trate into diseased gingival tissue.