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Epstein-Barr virus infection in chronically inflamed periapical granulomas.

Makino K, Takeichi O, Hatori K, Imai K, Ochiai K, Ogiso B - PLoS ONE (2015)

Bottom Line: In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001).Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells.In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Endodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.

ABSTRACT
Periapical granulomas are lesions around the apex of a tooth caused by a polymicrobial infection. Treatment with antibacterial agents is normally performed to eliminate bacteria from root canals; however, loss of the supporting alveolar bone is typically observed, and tooth extraction is often selected if root canal treatment does not work well. Therefore, bacteria and other microorganisms could be involved in this disease. To understand the pathogenesis of periapical granulomas more precisely, we focused on the association with Epstein-Barr virus (EBV) using surgically removed periapical granulomas (n = 32). EBV DNA was detected in 25 of 32 periapical granulomas (78.1%) by real-time PCR, and the median number of EBV DNA copies was approximately 8,688.01/μg total DNA. In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001). Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells. EBER was detected in the cytoplasm and nuclei of B cells and plasma cells in six of nine periapical granulomas, but not in healthy gingival tissues. In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells. These data suggest that B cells and plasma cells in inflamed granulomas are a major source of EBV infection, and that EBV could play a pivotal role in controlling immune cell responses in periapical granulomas.

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Histological evaluations of the specimens.Paraffin sections (n = 40) were stained using hematoxylin and eosin. Scale bar = 100μm. (A) Periapical granulomas (n = 32) showing a large number of inflammatory cells and microvessels. (B) Radicular cyst (n = 8) showing epithelial cell layer and cholesterol clefts. (C) Healthy gingival tissues (n = 10) showing epithelial cell layer and lower cell number of infiltrating cells in comparison with periapical granulomas.
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pone.0121548.g002: Histological evaluations of the specimens.Paraffin sections (n = 40) were stained using hematoxylin and eosin. Scale bar = 100μm. (A) Periapical granulomas (n = 32) showing a large number of inflammatory cells and microvessels. (B) Radicular cyst (n = 8) showing epithelial cell layer and cholesterol clefts. (C) Healthy gingival tissues (n = 10) showing epithelial cell layer and lower cell number of infiltrating cells in comparison with periapical granulomas.

Mentions: Surgically removed periapical lesions were examined pathologically. Of 40 periapical lesions stained with hematoxylin and eosin, 32 exhibited granulomatous tissues with large numbers of microvessels and inflammatory cells such as PMNs, lymphocytes, plasma cells, and macrophages (Fig 2A). No epithelial cells were observed, and the specimens were diagnosed as periapical granulomas. The remaining periapical lesions exhibited an epithelial cell lining with cholesterol clefts in granulomatous tissue and were diagnosed as radicular cysts (Fig 2B); these were not used in this study. The healthy gingival tissues contained more collagen fibers and fewer inflammatory cells in the granulomatous tissue than did the periapical granulomas (Fig 2C).


Epstein-Barr virus infection in chronically inflamed periapical granulomas.

Makino K, Takeichi O, Hatori K, Imai K, Ochiai K, Ogiso B - PLoS ONE (2015)

Histological evaluations of the specimens.Paraffin sections (n = 40) were stained using hematoxylin and eosin. Scale bar = 100μm. (A) Periapical granulomas (n = 32) showing a large number of inflammatory cells and microvessels. (B) Radicular cyst (n = 8) showing epithelial cell layer and cholesterol clefts. (C) Healthy gingival tissues (n = 10) showing epithelial cell layer and lower cell number of infiltrating cells in comparison with periapical granulomas.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401687&req=5

pone.0121548.g002: Histological evaluations of the specimens.Paraffin sections (n = 40) were stained using hematoxylin and eosin. Scale bar = 100μm. (A) Periapical granulomas (n = 32) showing a large number of inflammatory cells and microvessels. (B) Radicular cyst (n = 8) showing epithelial cell layer and cholesterol clefts. (C) Healthy gingival tissues (n = 10) showing epithelial cell layer and lower cell number of infiltrating cells in comparison with periapical granulomas.
Mentions: Surgically removed periapical lesions were examined pathologically. Of 40 periapical lesions stained with hematoxylin and eosin, 32 exhibited granulomatous tissues with large numbers of microvessels and inflammatory cells such as PMNs, lymphocytes, plasma cells, and macrophages (Fig 2A). No epithelial cells were observed, and the specimens were diagnosed as periapical granulomas. The remaining periapical lesions exhibited an epithelial cell lining with cholesterol clefts in granulomatous tissue and were diagnosed as radicular cysts (Fig 2B); these were not used in this study. The healthy gingival tissues contained more collagen fibers and fewer inflammatory cells in the granulomatous tissue than did the periapical granulomas (Fig 2C).

Bottom Line: In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001).Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells.In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Endodontics, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.

ABSTRACT
Periapical granulomas are lesions around the apex of a tooth caused by a polymicrobial infection. Treatment with antibacterial agents is normally performed to eliminate bacteria from root canals; however, loss of the supporting alveolar bone is typically observed, and tooth extraction is often selected if root canal treatment does not work well. Therefore, bacteria and other microorganisms could be involved in this disease. To understand the pathogenesis of periapical granulomas more precisely, we focused on the association with Epstein-Barr virus (EBV) using surgically removed periapical granulomas (n = 32). EBV DNA was detected in 25 of 32 periapical granulomas (78.1%) by real-time PCR, and the median number of EBV DNA copies was approximately 8,688.01/μg total DNA. In contrast, EBV DNA was not detected in healthy gingival tissues (n = 10); the difference was statistically significant according to the Mann-Whitney U test (p = 0.0001). Paraffin sections were also analyzed by in situ hybridization to detect EBV-encoded small RNA (EBER)-expressing cells. EBER was detected in the cytoplasm and nuclei of B cells and plasma cells in six of nine periapical granulomas, but not in healthy gingival tissues. In addition, immunohistochemical analysis for latent membrane protein 1 (LMP-1) of EBV using serial tissue sections showed that LMP-1-expressing cells were localized to the same areas as EBER-expressing cells. These data suggest that B cells and plasma cells in inflamed granulomas are a major source of EBV infection, and that EBV could play a pivotal role in controlling immune cell responses in periapical granulomas.

Show MeSH
Related in: MedlinePlus