title: Nitrogen-containing bisphosphonates modulate the antigenic profile and inhibit the maturation and biomineralization potential of osteoblast-like cells.
abstract: OBJECTIVE
  The aim was to evaluate the effect of three nitrogen-containing bisphosphonates at different concentrations on osteoblast growth, differentiation, and antigenic profile, using the MG-63 cell line as osteoblast model, in order to determine the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ).
  
  
  METHODS
  Osteoblasts were incubated in culture medium with 10(-5), 10(-7), or 10(-9) M of pamidronate, alendronate, or ibandronate. Proliferative capacity of the osteoblasts was determined by spectrophotometry (MTT) at 24 and 48 h of culture. Flow cytometry was used to study antigenic profile (CD54, CD80, CD86, HLA-DR) and phagocytic activity. Cell differentiation was evaluated at 7, 15, and 21 days by the study of nodule formation and alkaline phosphatase activity (ALP) at 24 h by spectrophotometric assay.
  
  
  RESULTS
  Pamidronate, alendronate, and ibandronate each exerted a significant stimulatory effect on MG63 proliferation that depended on the dose and treatment duration (p < 0.05). In general, a significantly decreased expression of CD54, CD80, and HLA-DR membrane antigens was observed after 24 h of treatment with each nitrogen-containing bisphosphonate (p < 0.05), but there was no significant difference in phagocytic activity versus controls. A decrease in ALP activity was observed after 24 h of treatment and a decrease in calcium deposition after 15 and 21 days (p < 0.05).
  
  
  CONCLUSIONS
  Nitrogen-containing bisphosphonates can increase the proliferation of MG-63 osteoblast-like cells, modulate their expression of co-stimulatory molecules associated with immune function, and decrease their differentiation capacity, generally at low doses.
  
  
  CONCLUSIONS
  These findings suggest that low doses of nitrogen-containing bisphosphonates exert their effect on osteoblasts by altering their physiology, which would explain the disruption of their repair capacity and may be directly related to the development of BRONJ.
authors.affiliation: Department of Stomatology, School of Dentistry. Instituto de Investigación Biosanitaria ibs.GRANADA, University of Granada, Granada, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Manzano-Moreno
authors.forename: Javier
authors.initials: J
authors.lastname: Ramos-Torrecillas
authors.forename: Elvira
authors.initials: E
authors.lastname: De Luna-Bertos
authors.forename: Candela
authors.initials: C
authors.lastname: Reyes-Botella
authors.forename: Concepción
authors.initials: C
authors.lastname: Ruiz
authors.forename: Olga
authors.initials: O
authors.lastname: García-Martínez
mesh_terms: D015703:Antigens, CD / Q000032:analysis* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004164:Diphosphonates / Q000737:chemistry / Q000494:pharmacology*; D006684:HLA-DR Antigens / Q000032:analysis / Q000378:metabolism; D006801:Humans; D009584:Nitrogen; D010006:Osteoblasts / Q000737:chemistry / Q000187:drug effects / Q000276:immunology
chemical_list: D015703:Antigens, CD; D004164:Diphosphonates; D006684:HLA-DR Antigens; D009584:Nitrogen