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Yang CY, Chang ZF, Chau YP, Chen A, Lee OKS, Yang AH. Uremia Induces Dental Pulp Ossification but Reciprocally Inhibits Adjacent Alveolar Bone Osteogenesis. Calcif Tissue Int 2015; 97:466-75. [PMID: 26126938 DOI: 10.1007/s00223-015-0030-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/20/2015] [Indexed: 01/09/2023]
Abstract
Uremic patients are predisposed to atrophy of the alveolar bone and narrowing of the dental pulp chamber. Such pulp chamber changes have only been diagnosed radiologically; however, this has not been supported by any pathological evidence. We used a uremic rat model with secondary hyperparathyroidism induced by 5/6 nephrectomy surgery and high-phosphate diet to examine the dental pulp and adjacent alveolar bone pathology. In addition, we collected pulp tissues for real-time PCR. We found an opposite histopathological presentation of the ossified dental pulp and the osteomalacic adjacent alveolar bone. Furthermore, pulp cells with positive staining for Thy-1, a surrogate stem cell marker, were significantly reduced in the pulp of uremic rats compared to the controls, indicating a paucity of stem cells. This was further evidenced by the reduced pulp expression of dickkopf-1 (Dkk-1), a Wnt/β-catenin signaling inhibitor produced by mesenchymal stem cells. In contrast, expressions of receptor activator of nuclear factor κB ligand (RANKL) and RANK in uremic pulp were up-regulated, probably to counteract the ossifying process of uremic pulp. In conclusion, uremic pulp ossifications were associated with a paucity of stem cells and dysregulated Dkk-1 and RANKL signaling systems, further shifting the imbalance toward osteogenesis. Strategies to counteract such an imbalance may offer a potential therapeutic target to improve dental health in uremic patients, which warrants further interventional studies.
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Affiliation(s)
- Chih-Yu Yang
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Zee-Fen Chang
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Yat-Pang Chau
- Department of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Ann Chen
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Oscar Kuang-Sheng Lee
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.
- Department of Orthopedic Surgery, Taipei City Hospital, No. 10, Sect. 4, Ren-Ai Road, Da-An District, Taipei, 10629, Taiwan.
- Departments of Medical Research and Orthopedic Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.
- Stem Cell Research Center, National Yang-Ming University, Taipei, Taiwan.
| | - An-Hang Yang
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.
- School of Medicine, National Yang-Ming University, Taipei, Taiwan.
- Department of Pathology, Taipei Veterans General Hospital, No. 201, Sect. 2, Shih-Pai Road, Beitou District, Taipei, 11217, Taiwan.
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Regional aggressive root resorption caused by neuronal virus infection. Case Rep Dent 2012; 2012:693240. [PMID: 23097724 PMCID: PMC3477661 DOI: 10.1155/2012/693240] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 09/15/2012] [Indexed: 12/27/2022] Open
Abstract
During orthodontic treatment, root resorption can occur unexplainably. No clear distinction has been made between resorption located within specific regions and resorption occurring generally in the dentition. The purpose is to present cases with idiopathic (of unknown origin) root resorption occurring regionally. Two cases of female patients, 26 and 28 years old, referred with aggressive root resorption were investigated clinically and radiographically. Anamnestic information revealed severe virus diseases during childhood, meningitis in one case and whooping cough in the other. One of the patients was treated with dental implants. Virus spreading along nerve paths is a possible explanation for the unexpected resorptions. In both cases, the resorptions began cervically. The extent of the resorption processes in the dentition followed the virus infected nerve paths and the resorption process stopped when reaching regions that were innervated differently and not infected by virus. In one case, histological examination revealed multinuclear dentinoclasts. The pattern of resorption in the two cases indicates that innervation is a factor, which under normal conditions may protect the root surface against resorption. Therefore, the normal nerve pattern is important for diagnostics and for predicting the course of severe unexpected root resorption.
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