Investigation of host factor in early-onset peiodontitis on people with Down syndrome.

众所周知，唐氏综合征(DS)患者对感染的防御机制脆弱，并且容易由牙周病的最相关病原体牙龈卟啉单胞菌引起的早发性和严重的成人牙周炎。由牙周组织组成的牙周上皮细胞和成纤维细胞是抵御包括牙龈假单胞菌在内的病原微生物入侵的前屏障。然而，关于双链球菌对牙龈假单胞菌感染的宿主反应的研究很少。在本研究项目中，我们试图开发改良的培养方法，以提高HGE培养的难度。通过侵袭实验和共聚焦显微镜观察，比较了DS来源的HGE和正常人(NS)来源的HGf对牙周炎杆菌感染的敏感性。与有血清培养相比，DS来源的HGE在无血清培养上具有更高的选择性，但仍难以…更多的是在无血清培养液中培养HGE。这种现象似乎是由于DS细胞中过多的染色体和减少的端粒，通过蛋白质合成的恶化而导致细胞分裂和维持的改变。体外侵袭实验表明，DS来源的HGE比NS来源的HGE对牙龈假单胞菌感染更敏感。在这项研究中，我们发现牙龈假单胞菌从DS到HGF的黏附和侵袭比从NS到HGF的更多。共聚焦显微镜观察结果显示，DS牙周组织中的牙周组织上皮细胞和成纤维细胞对P.givalis感染均较敏感，DS牙周组织中的牙周组织上皮细胞和成纤维细胞对P.givalis感染均较敏感。结论DS牙周组织上皮细胞和成纤维细胞对P.givalis感染易感，这可能是DS牙周组织中Pg感染的原因之一。较少

Person with Down syndrome (DS) has been known to be vulnerable in defence mechanism against infection and susceptible to an early-onset as well as a severe adult periodontitis caused by Porphyromonas gingivalis which is the most relevant pathogen of the periodontal disease. Gingival epithelial cells (HGE) and fibroblasts (HGF) consisting of periodontal tissue are acting as a front barrier against invasion of pathogenic microorganisms including P.gingivalis. However, there is little study on the host responses of DS HGE to P.gingivalis infection. In this research project, we tried to develop the modified culture method for improving difficulty of HGE culture. Then we compared the susceptibility of HGE and HGF derived from both DS and normal subjects (NS) to P.gingivalis infection by invasion assay and confocal microscopic observasion.The HGE derived from DS could be cultured more selectively in the medium without serum compared to medium containing serum, however, it was still difficult … More to culture HGE in the serum free medium. This phenomenon seems to be due to an excess chromosome and reduced telomere in DS cells causing altered cell division and maintenance by deteriorated protein synthesis. Invasion assay showed HGE derived from DS was more susceptible to P.gingivalis infection in vitro than HGE from NS.Recently, it was reported that P.gingivalis could adhere and invade to HGF. In this study, we showed that greater number of P.gingivalis had adhered and invaded to HGF from DS than to HGF from NS. These finding indicated that not only HGE but DS-derived HGF, existing beneath the epithelial cell layer, was more susceptible to P.gingivalis than these from NS.Confocal microscopic observation showed that the numbers of P.gingivalis -invaded into both HGE and HGF from DS were grater than those incaded into HGE and HGF from NS, respectively, suggesting that the gingival cells from DS are more susceptible to P.gingivalis infection in vitro than those cells from NS.In conclusion, epithelial cells and fibroblasts of DS periodontal tissue are susceptible to P.gingivalis infection, and these altered defence mechanism could be responsible for early-onset severe periodontitis in DS. Less