title: Significance of peptidoglycan, a proinflammatory bacterial antigen in atherosclerotic arteries and its association with vulnerable plaques.
abstract: Peptidoglycan (PG) is a major component of the cell wall of gram-positive bacteria that is abundantly present in all human mucosa. PG is a functional lipopolysaccharide analog that binds to CD14 on macrophages and induces proinflammatory cytokine production and metalloproteinases. We investigated the hypothesis that bacterial PG is present in atherosclerotic tissue. In addition, plaque phenotypes were characterized in relation to presence of PG. Immunohistology of carotid (n = 15) and femoral (n = 6) endarterectomy specimens revealed the presence of PG in the cytoplasm of cells located in plaques. PG was detected in 14 of 15 carotid arteries and 5 of 6 femoral arteries. From the 14 coronary arteries, 31 atherosclerotic segments were selected. PG was detected within 19 of 31 of these coronary segments. Western blot demonstrated the presence of the toll-like receptor (TLR-2), the co-receptor for PG, in coronary artery tissue. The number of PG-containing cells in coronary arteries was significantly higher when the histologic features of plaque vulnerability were evident. Inflammation of the cap or shoulder was observed in 11 of 19 PG-positive versus 2 of 12 PG-negative segments (p = 0.023). More than 50% of the plaque area consisted of atheroma in 7 of 19 PG-positive segments and 0 of 12 PG-negative segments (p = 0.025). Heavy smooth muscle cell staining occurred in the plaque cap and shoulder in 3 of 19 PG-positive segments versus 9 of 12 PG-negative segments. Proinflammatory bacterial PG and its co-receptor have been observed in atherosclerotic arteries, in association with the vulnerable plaque phenotype.
authors.affiliation: Department of Immunology, Erasmus University Rotterdam and University Hospital Rotterdam, Dijkzigt, The Netherlands. laman@immu.fgg.eur.nl
authors.forename: Jon D
authors.initials: JD
authors.lastname: Laman
authors.forename: Arjan H
authors.initials: AH
authors.lastname: Schoneveld
authors.forename: Frans L
authors.initials: FL
authors.lastname: Moll
authors.forename: Marjan
authors.initials: M
authors.lastname: van Meurs
authors.forename: Gerard
authors.initials: G
authors.lastname: Pasterkamp
mesh_terms: D000368:Aged; D002102:Cadaver; D002339:Carotid Arteries / Q000473:pathology; D003324:Coronary Artery Disease / Q000382:microbiology* / Q000473:pathology; D029721:Drosophila Proteins; D004691:Endarterectomy; D005260:Female; D005263:Femoral Artery / Q000473:pathology; D006094:Gram-Positive Bacteria / Q000276:immunology* / Q000472:pathogenicity*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000302:isolation & purification; D010457:Peptidoglycan / Q000302:isolation & purification*; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000302:isolation & purification; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors
chemical_list: D029721:Drosophila Proteins; D008562:Membrane Glycoproteins; D010457:Peptidoglycan; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors