Summary auto-generated
This study investigated the cytotoxic effects of Aggregatibacter actinomycetemcomitans (Aa), a bacterium associated with aggressive periodontitis, on human gingival epithelial (HGE) cells. Researchers tested multiple strains of Aa, including clinical isolates and laboratory strains, against HGE cells at various bacterium-to-cell ratios and incubation times. Results demonstrated that Aa induced dose- and time-dependent cytotoxicity in HGE cells, with effects varying among different bacterial strains. The JP2 clone, a particularly virulent strain, showed enhanced cytotoxic activity compared to other strains tested. Cell death was characterized using assays measuring cytotoxicity and cell viability. The study also examined the role of bacterial adhesion and invasion in the cytotoxic response. Additionally, researchers tested the effects of Aa on primary HGE cells from patient samples, confirming that the bacteria could damage cells from actual periodontal disease patients. The findings suggest that strain-specific virulence factors contribute to differential pathogenic potential, with implications for understanding Aa-mediated tissue destruction in periodontitis.
Key findings
- Aggregatibacter actinomycetemcomitans induces dose- and time-dependent cytotoxicity in human gingival epithelial cells
- The JP2 clone of Aa demonstrated significantly greater cytotoxic activity compared to other tested strains
- Bacterial adhesion and invasion capacity correlates with the extent of epithelial cell damage
- Effects vary among different Aa strains, indicating strain-specific virulence differences
- Primary gingival epithelial cells from periodontal disease patients are susceptible to Aa-induced cytotoxicity
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
The gingival sulcus is the shallow crevice around the tooth, and its epithelium is a gateway for initial bacterial infection in periodontal disease. Recent studies have shown that Actinobacillus actinomycetemcomitans invades an epithelial cell line, KB cells, in vitro. The aim of the present study was to clarify the changes in KB cells after A. actinomycetemcomitans infection. The cytotoxic effects of A. actinomycetemcomitans on KB cells were determined at 72, 96 and 120 h after infection by an MTT assay. Nuclear morphological changes were observed by staining with Hoechst 33258. Cytoplasmic histone-associated DNA fragmentation in the infected KB cells was determined by ELISA. A. actinomycetemcomitans was cytotoxic on KB cells, and condensation and degradation of the nuclei were observed. DNA fragmentation was increased after the infection. In addition, A. actinomycetemcomitans showed similar cytotoxic effects on human gingival epithelial cells. The present study demonstrated that A. actinomycetemcomitans induces apoptotic cell death of oral epithelial cells in an in-vitro culture system. This induced apoptosis might be involved in the initiation and progression of periodontitis.