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Inhibited proliferation of human periodontal ligament cells and gingival fibroblasts by Actinobacillus actinomycetemcomitans : involvement of the cytolethal distending toxin
Author(s) -
Belibasakis Georgios,
Johansson Anders,
Wang Ying,
Claesson Rolf,
Chen Casey,
Asikainen Sirkka,
Kalfas Sotirios
Publication year - 2002
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1034/j.1600-0722.2002.21350.x
Subject(s) - cytolethal distending toxin , actinobacillus , periodontal fiber , cell growth , apoptosis , fibroblast , microbiology and biotechnology , cell , lysis , cell culture , chemistry , dna synthesis , biology , toxin , dna , bacteria , dentistry , medicine , microbial toxins , biochemistry , genetics
Actinobacillus actinomycetemcomitans can inhibit fibroblast proliferation. The objective of this study was to characterize the early proliferative responses of human periodontal ligament cells (PDLC) and gingival fibroblasts (GF) to A. actinomycetemcomitans components and to investigate the possible involvement of the cytolethal distending toxin (cdt) produced by this bacterium. The PDLC and GF were challenged with surface components of A. actinomycetemcomitans. Both DNA and protein synthesis as well as cell lysis or apoptosis were assayed for a 6‐h period after addition of the bacterial extract. Unlike the controls, inhibition of DNA synthesis had already occurred in the challenged cells at the end of the initial 3‐ to 6‐h period. No lysis or apoptosis was detected, and the total protein synthesis remained unaffected. The persistence of the effect on cell growth was confirmed after a 72‐h period of challenge, during which the cells remained viable but exhibited an elongated and distended cell body. No significant differences were observed between PDLC and GF. When a cdt‐knockout strain of A. actinomycetemcomitans was used almost no inhibitory effect on cell proliferation was observed. It was concluded that A. actinomycetemcomitans causes a non‐lethal inhibition of proliferation in PDLC and GF as a result of an early arrest of DNA synthesis. Cytolethal distending toxin is responsible for most of this effect. This bacterial property may compromise tissue homeostasis in the periodontium.