| Project/Area Number |
12671994
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
AMANO Atsuo Graduate School of Dentistry, OSAKA UNIVERSITY, Professor, 大学院・歯学研究科, 教授 (50193024)
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| Co-Investigator(Kenkyū-buntansha) |
AKIYAMA Shigehisa Dental Hospital, OSAKA UNIVERSITY, Senior Instructor, 歯学部・附属病院, 助手 (00283797)
MORISAKI Ichijiro Dental Hospital, OSAKA UNIVERSITY, Professor, 歯学部・附属病院, 教授 (30116115)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Periodontitis / Porphyromonas gingivalis / Genotype / Genotyping / Plaque bacteria / Polymerase chain reaction / fimbriae / fimA / 線毛遺伝子(fimA) / PCR / 細菌分布 / 歯周病原性菌 / インテグリン / リコンビナント線毛 |
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| Research Abstract |
Adult periodontitis is a highly destructive chronic inflammatory disease resulting from the complex actions of a small subset of periodontal bacteria. Among them, Porphyromonas gingivalis has been characterized as a bona fide periodontal pathogen.
This microorganism has been frequently detected in patients with periodontitis, while it reportedly occurs at a lower frequency in periodontally healthy individuals without marked gingival inflammation. There may be diversities in virulence among the organisms harbored by individuals who are periodontally healthy and those with periodontitis. However, it is still unknown whether periodontitis can develop only in the presence of virulent strain(s) of P. gingivalis, or if other host factors, such as genetic background and environmental stress, may have a determining influence in the initiation of the disease in individuals infected by the organism.
Porphyromonas gingivalis fimA gene encoding fimbrillin, a subunit of fimbriae, has been classified
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into five genotypes (types I to V) based on their nucleotide sequences. We investigated the relationship between the prevalence of these fimA genotypes and periodontal health status in adults. P. gingivalis was detected in 36.8% of dental plaque specimens from the 380 periodontally healthy adults and in 87. 1% of those from 139 periodontitis patients by PCR method. The most prevalent fimA type was type I (76.1%) in healthy subjects, and a majority of the periodontitis patients carried type II fimA organisms (66. 1 %). The univariate analysis illustrated that periodontitis were associated with the occurrences of type I fimA (odds ratio=0. 16), type II (44.44), type III (1.96), type IV (13.87), and type V (1.40). We further compared adhesion/invasion abilities of recombinant FimA (rFimA) of types I to V to human epithelial cell line (HEp-2 cell). The adhesion/invasion of type II rFimA-conjugated microspheres to HEp-2 cells was significantly greater than those of other rFimA types. Furthermore, P. gingivalis strain HW24D1 with type II fimA adhered to cells and invaded them more than strains with other fimA genotypes.
These findings clearly indicate that there are both disease-associated and non-disease-associated strains of P. gingivalis, and it could be of value for their therapeutic aspects and in the assessment of the prognosis of periodontitis if the disease-contributing strains would be differentiated based on the clonal variations of the fimA gene. Less
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