title: Advanced glycation end-products enhance calcification in cultured rat dental pulp cells.
abstract: BACKGROUND
  Amorphous calcification frequently appears in dental pulp tissues of diabetic patients; however, its pathologic process has not been fully elucidated. We previously found that pulp stones and thickened predentin occurred more frequently in diabetic rats. Recent findings demonstrated that accumulation of advanced glycation end-products (AGE) might be involved in vascular calcification complicated with diabetes. The aim of this study was to determine the effect of AGE on calcified nodule formation by rat dental pulp cells in culture.
  
  
  METHODS
  Rat dental pulp cells and gingival fibroblasts were independently cultured with 50 and 100 μg/mL AGE. Alkaline phosphatase activity and calcified nodule formation were measured. Expressions of receptor for AGE, osteopontin (OPN), and osteocalcin (OCN) mRNA were determined by quantitative real-time polymerase chain reaction. Protein levels of OPN and OCN secreted in culture medium were quantified by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  AGE (50 and 100 μg/mL) markedly increased both alkaline phosphatase activity and calcified nodule formation in dental pulp cells (P < .01), whereas it did not affect those in gingival fibroblasts. Real-time polymerase chain reaction analysis revealed that AGE increased mRNA expressions of receptor for AGE, OPN, and OCN in dental pulp cells (P < .05). Enzyme-linked immunosorbent assay analysis revealed that the protein levels of OPN and OCN produced by dental pulp cells were higher in AGE-treated than in untreated cells (P < .05).
  
  
  CONCLUSIONS
  AGE enhanced the calcification potentials of rat dental pulp cells, suggesting that it may stimulate pathologic calcification of diabetic dental pulp tissues.
authors.affiliation: Department of Periodontology and Endodontology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakajima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Yuka
authors.initials: Y
authors.lastname: Hiroshima
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kido
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Nagata
mesh_terms: D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D003784:Dental Pulp Calcification / Q000473:pathology*; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects; D017127:Glycation End Products, Advanced / Q000494:pharmacology*; D008297:Male; D015675:Osteocalcin / Q000032:analysis; D053495:Osteopontin; D051381:Rats; D017208:Rats, Wistar; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000032:analysis; D013997:Time Factors
chemical_list: D017127:Glycation End Products, Advanced; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C506897:Spp1 protein, rat; D015675:Osteocalcin; D053495:Osteopontin; D000469:Alkaline Phosphatase