Porphyromonas gingivalis invades human pocket epithelium in vitro

Abstract

The present study examined the adhesive and invasive potential of Porphyromonas gingivalis interacting with human pocket epithelium in vitro. Pocket epithelial tissue, obtained during periodontal surgery of patients with advanced periodontal disease, generated a stratified epithelium in culture. P. gingivalis strains W50 and FDC 381 (laboratory strains), OMGS 712, 1439, 1738, 1739 and 1743 (clinical isolates) as well as Escherichia coli strain HB101 (non-adhering control) were tested with respect to epithelial adhesion and invasion. Adhesion was quantitated by scintillation spectrometry after incubation of radiolabeled bacteria with epithelial cells. The invasive ability of P. gingivalis was measured by means of an antibiotic protection assay. The epithelial multilayers were infected with the test and control strains and subsequently incubated with an antibiotic mixture (metronidazole 0.1 mg/ml and gentamicin 0.5 mg/ml). The number of internalized bacteria surviving the antibiotic treatment was assessed after plating lyzed epithelial cells on culture media. All tested P. gingivalis strains adhered to and entered pocket epithelial cells. However, considerable variation in their adhesive and invasive potential was observed. E. coli strain HB101 did not adhere or invade. Transmission electron microscopy revealed that internalization of P. gingivalis was preceded by formation of microvilli and coated pits on the epithelial cell surfaces. Intracellular bacteria were most frequently surrounded by endosomal membranes; however, bacteria devoid of such membranes were also seen. Release of outer membrane vesicles (blebs) by internalized P. gingivalis was observed. These results support and extend previous work from this laboratory which demonstrated invasion of a human oral epithelial cell-line (KB) by P. gingivalis.

Oral Infection With a Periodontal Pathogen Accelerates Early Atherosclerosis in Apolipoprotein E–Null Mice

“…18,19 Once bacteria gain access to these sites, their byproducts incite periods of exacerbation and remission of inflammation, leading to increased production of proinflammatory cytokines and matrix metalloproteinases, often by augmenting mechanisms linked to evasion of host defenses. 20,21 A consequence of this heavy burden of cytokines and tissue-destructive mediators is the development of hyperpermeability and loss of epithelial integrity, which creates an opportunity for invading bacteria, and their byproducts, to gain access to the systemic circulation.…”

Identification of oral bacteria associated with crevicular epithelial cells from chronic periodontitis lesions

“…Yet, the complex relationship between the subgingival microbiota and the epithelium of the gingival crevice in such infections has only been partially determined. A great deal of evidence has accumulated which corroborates the ability of putative periodontal pathogens, such as Prevotella intermedia (Dorn et al, 1998), Actinobacillus actinomycetemcomitans (FivesTaylor et al, 1995;Meyer et al, 1996;Rudney et al, 2001), Porphyromonas gingivalis (Sandros et al, 1994;Lamont et al, 1995;Madianos et al, 1996), Fusobacterium nucleatum (Han et al, 2000), and several species of oral spirochaetes (Peters et al, 1999), to adhere to and invade oral epithelial tissues and cells. However, most of these studies were performed in vitro, using few reference bacterial strains, and oral epithelial cell lines, primary epithelial cell cultures or cells from the buccal mucosa.…”

Nuclear Targeting ofPorphyromonas gingivalisW50 Protease in Epithelial Cells

“…The organism can invade gingival tissue in advanced periodontitis (18) and can be taken up by gingival and pocket epithelial cells, oral epithelial cell lines, and endothelial cells in vitro (13,23,33,40). The nature of the eukaryotic surface receptor molecules and the signal transduction pathways required for internalization of P. gingivalis by oral epithelial cells remain to be clarified.…”