Distribution of 3-hydroxy iC17:0 in subgingival plaque and gingival tissue samples: relationship to adult periodontitis

Abstract

Gram-negative organisms incorporate hydroxy fatty acids into the lipid A moiety of lipopolysaccharide (LPS), and in the case of some members of the family Enterobacteriaceae, hydroxy fatty acids are incorporated exclusively into lipid A. However, a limited number of Bacteroides species have been shown to incorporate several classes of 3-hydroxy fatty acids, particularly 3-hydroxy iC17:0, into constitutive lipids as well as LPS. The present study examined the distribution of hydroxy fatty acids in two periodontal pathogens, Prevotella intermedia and Porphyromonas gingivalis, by employing a phospholipid extraction procedure (E. G. Bligh and W. J. Dyer, Can. J. Biochem. Physiol. 37:911-917, 1959) which partitioned constitutive lipids into the organic solvent phase and LPS into the aqueous phase. The distribution of hydroxy fatty acids within organic solvent and aqueous extracts of these bacterial species was then compared with the distribution in subgingival plaque samples isolated from either gingivitis or severe periodontitis sites as well as the distribution in gingival tissue samples. The organic solvent and aqueous extracts were hydrolyzed under strong alkaline conditions, and the free fatty acids were treated to form pentafluorobenzyl-ester, trimethylsilyl-ether derivatives. Hydroxy fatty acid levels were quantified by using gas chromatography-negative-ion chemical ionization-mass spectrometry. By using this approach, the mean values of the 3-hydroxy iC17:0 recovered within organic solvent extracts of P. gingivalis strains ranged from 56 to 63% of total 3-hydroxy iC17:0. Substantially less 3-hydroxy iC17:0 (< 5%) was recovered in organic solvent extracts of P. intermedia. By comparison, 75% of the 3-hydroxy iC17:0 in periodontitis subgingival plaque samples was recovered in organic solvent extracts, while only 43% of the 3-hydroxy iC17:0 in gingivitis plaque samples from the same patients was recovered in organic solvent extracts. However, 3-hydroxy iC17:0 was recovered essentially only in organic solvent extracts of both healthy or mildly inflamed and periodontitis gingival tissue samples. The preferential recovery of 3-hydroxy iC17:0 in tissue lipids indicates that gingival tissues do not harbor significant levels of subgingival plaque organisms which contain 3-hydroxy iC17:0. Furthermore, these results indicate that LPS from these organisms is not prevalent in gingival tissues. Finally, these results indicate either selective penetration of certain bacterial lipids into gingival tissues or that 3-hydroxy iC17:0 is metabolically transferred from bacterial lipids into gingival tissue lipids.

The lipid A region of lipopolysaccharides from Rhizobiaceae activates bone marrow granulocytes from lipopolysaccharide‐hyporesponsive C3H/HeJ andC57BL/10ScCr mice

“…12 This is probably due to the unique chemical features of the lipid A moieties of these LPSs, such as the presence of 15-methylhexadecanoate in P. gingivalis, 10,13±15 and 3-hydroxy-15-methylhexadecanoate in P. intermedia. 16 Because Gram-negative bacteria belonging to the family Rhizobiaceae infect plants instead of animals, and because the structure of their lipid A exhibits several major differences when compared with lipid A of enterobacteria, we decided to examine the in¯uence of some LPSs isolated from this family of bacteria on cells from normal and LPS-hyporesponsive mice. Bone marrow cells (BMC) represent interesting cellular targets because we established in several previous studies that an LPS receptor of low af®nity, distinct from CD14, is constitutively present on these cells, 17 and that the interaction of Salmonella LPS with this receptor triggers the expression of CD14.…”

Prostaglandin E2 secretion from gingival fibroblasts treated with interleukin‐1β: effects of lipid extracts from Porphyromonas gingivalis or calculus

“…Flavobacterium and Myxobacteria are not reported to be constituent organisms of subgingival plaque and the recovery of 3-OH isoC 17:0 in organic solvent and aqueous solvent extracts of plaque and gingival tissue samples is presumed to re¯ect the recovery of Porphyromonas, Prevotella, Bacteroides and Capnocytophaga species only. Using aqueous and organic solvent partitioning, the present study demonstrated that the majority of 3-OH isoC 17:0 (62% of the total) in subgingival plaque samples is recovered in the aqueous phase, most likely in lipopolysaccharide (2). However, 3-OH isoC 17:0 was recovered predominantly in lipid extracts from periodontally hopeless teeth (58% of the total 3-OH isoC 17:0 ) and root samples with visible calculus (67% of the total 3-OH isoC 17:0 ).…”

“…This evidence con®rms that the process of sectioning tooth roots contaminated with calculus does not signi®cantly aect the distribution of bacterial lipids. According to a previous report, 58% of the total 3-OH isoC 17:0 in P. gingivalis is recovered in organic solvent extract (2). Of the remaining intraoral organisms tested (Prevotella intermedia, Capnocytophaga ochracea, Capnocytophaga gingivalis and Capnocytophaga sputigena, generously provided by Dr Paulette Tempro, Department of Periodontology, SUNY, Bualo, USA), 3-OH isoC 17:0 is generally incorporated into lipids to an equal or lesser extent than P. gingivalis (data not shown).…”

“…Because 3-OH isoC 17:0 is recovered in lipid extracts of calculuscontaminated root slices in excess of that observed in plaque samples and P. gingivalis, these results argue that bacterial lipids containing 3-OH isoC 17:0 are selectively adsorbed to root surfaces and may be concentrated in or on subgingival calculus. A previous report demonstrated that 3-OH isoC 17:0 is recovered virtually only in organic solvent extracts of gingival tissue samples, with negligible levels of 3-OH isoC 17:0 recovered in aqueous soluble extracts (2). Furthermore, only a limited number of lipids from P. gingivalis or subgingival plaque, which contain 3-OH isoC 17:0 , are also recovered in gingival tissues (2).…”

“…Regardless of the disease status of periodontal connective tissue, the predominant cell type recovered in gingival connective tissue is the ®broblast (5). Gingival ®broblasts are expected to be exposed to the previously mentioned bacterial lipids given the impressive recovery of bacterial lipids in diseased periodontal tissues (2,6). Furthermore, gingival ®broblasts are capable of secreting impressive levels of prostaglandin E 2 (7), a soluble host factor capable of proin¯ammatory eects with potentially adverse eects on bone and connective tissue homeostasis.…”