Department of Oral Microbiology, Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU University Amsterdam, The Netherlands.
Microb Pathog. 2011 Sep;51(3):149-55. doi: 10.1016/j.micpath.2011.04.006. Epub 2011 Apr 27.
Porphyromonas gingivalis is associated with periodontitis, a chronic inflammatory disease of the tooth-supporting tissues. A major clinical symptom is alveolar bone loss due to excessive resorption by osteoclasts. P. gingivalis may influence osteoclast formation in diverse ways; by interacting directly with osteoclast precursors that likely originate from peripheral blood, or indirectly by activating gingival fibroblasts, cells that can support osteoclast formation. In the present study we investigated these possibilities. Conditioned medium from viable or dead P. gingivalis, or from gingival fibroblasts challenged with viable or dead P. gingivalis were added to human mononuclear osteoclast precursors. After 21 days of culture the number of multinucleated (≥3 nuclei) tartrate resistant acid phosphatase (TRACP)-positive cells was determined as a measure for osteoclast formation. Conditioned medium from viable P. gingivalis, and from fibroblasts with viable P. gingivalis stimulated osteoclast formation (1.6-fold increase p < 0.05). Conditioned medium from dead bacteria had no effect on osteoclast formation, whereas conditioned medium from fibroblasts with dead bacteria stimulated formation (1.4-fold increase, p < 0.05). Inhibition of P. gingivalis LPS activity by Polymyxin B reduced the stimulatory effect of conditioned medium. Interestingly, when RANKL and M-CSF were added to cultures, conditioned media inhibited osteoclast formation (0.6-0.7-fold decrease, p < 0.05). Our results indicate that P. gingivalis influences osteoclast formation in vitro in different ways. Directly, by bacterial factors, likely LPS, or indirectly, by cytokines produced by gingival fibroblasts in response to P. gingivalis. Depending on the presence of RANKL and M-CSF, the effect of P. gingivalis is either stimulatory or inhibitory.
牙龈卟啉单胞菌与牙周炎有关，牙周炎是一种牙齿支持组织的慢性炎症性疾病。主要的临床症状是由于破骨细胞的过度吸收导致牙槽骨丧失。牙龈卟啉单胞菌可能通过多种方式影响破骨细胞的形成；通过直接与可能来源于外周血的破骨细胞前体相互作用，或通过间接激活牙龈成纤维细胞，这些细胞可以支持破骨细胞的形成。在本研究中，我们研究了这些可能性。添加来自活的或死的牙龈卟啉单胞菌的条件培养基，或来自用活的或死的牙龈卟啉单胞菌刺激的牙龈成纤维细胞的条件培养基，到人单核细胞破骨细胞前体中。在 21 天的培养后，通过抗酒石酸酸性磷酸酶（TRACP）阳性多核细胞（≥3 核）的数量来确定破骨细胞形成的情况。来自活的牙龈卟啉单胞菌的条件培养基和来自具有活的牙龈卟啉单胞菌的成纤维细胞的条件培养基刺激破骨细胞形成（增加 1.6 倍，p<0.05）。死细菌的条件培养基对破骨细胞形成没有影响，而来自具有死细菌的成纤维细胞的条件培养基刺激形成（增加 1.4 倍，p<0.05）。多粘菌素 B 抑制牙龈卟啉单胞菌 LPS 活性降低了条件培养基的刺激作用。有趣的是，当向培养物中添加 RANKL 和 M-CSF 时，条件培养基抑制破骨细胞形成（减少 0.6-0.7 倍，p<0.05）。我们的结果表明，牙龈卟啉单胞菌以不同的方式影响体外破骨细胞的形成。直接通过细菌因子，可能是 LPS，或间接通过牙龈成纤维细胞对牙龈卟啉单胞菌的反应产生的细胞因子。取决于 RANKL 和 M-CSF 的存在，牙龈卟啉单胞菌的作用是刺激或抑制。
