Methods: Healthy periodontal tissues were obtained from extracted third molars from donors without any oral disease. Inflamed cells were obtained from extracted teeth with periodontal lesions. Established antibiotic combinations of penicillin, streptomycin and amphotericin B were used for PDL cell culture. In contrast, for inflamed PDL-fibroblasts, combinations of amoxicillin and metronidazole were applied. Both groups of PDL-fibroblasts were characterized by fluorescence-activated-cell-sorting (FACS), applying markers associated with stem cells (CD29, CD13 and CD73) and collagen type I, and real-time polymerase-chain-reaction (RT-PCR).
Results: No differences were detected for the level of CD29 (integrin β1), in healthy and inflamed PDL-fibroblasts. Significant differences were found for the levels of CD13 (Aminopeptidase N), which increased in inflamed fibroblasts, and for CD73 (Ecto-5'-Nucleotidase), which decreased in inflamed fibroblasts. We demonstrated, that mRNA levels of CD73 remain stable through passage 5, while levels of CD29 decreased. Furthermore, inflamed PDL-fibroblasts exhibited lower levels of collagen type I than healthy PDL-fibroblasts.
Conclusion: The increased level of CD13 for inflamed PDL-fibroblasts is in line with its association with cells of the immune system and its postulated functions to control anti-bacterial activities. Furthermore, it could be correlated with periodontitis because CD13 is a membrane bound metalloprotease, which degrades regulatory peptides.
Lower intracellular levels of collagen type I in inflamed PDL-fibroblasts correlate with tissue degradation in periodontitis.
We demonstrated stem-cell-properties for both, healthy and inflamed fibroblasts of the PDL, on the protein level by FACS and on mRNA level by RT-PCR.