Effect of Clodronate on Antigenic Profile, Growth, and Differentiation of Osteoblast-Like Cells.
OBJECTIVE
To evaluate the role of osteoblasts in bisphosphonate-related osteonecrosis of the jaw (BRONJ) by studying the effects of different concentrations of clodronate, a non-nitrogen-containing bisphosphonate, on osteoblast growth, differentiation, and antigenic profile.


METHODS
Osteoblast-like cells (MG63) were incubated in culture medium with different doses of clodronate. Their proliferative capacity was determined with a spectrophotometric technique (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium assay). Flow cytometry was used to study the antigenic profile. Cell differentiation was evaluated by nodule formation and alkaline phosphatase (ALP) activity was measured by spectrophotometric assay.


RESULTS
Clodronate had a significant stimulatory effect on osteoblast-like cell (MG63) proliferation (P < .05). A significant decrease in the expression of CD54, CD80, CD86, and HLA-DR membrane antigens versus controls was observed after 24 hours of treatment with the different clodronate doses assayed (P < .05). A significant decrease (P = .004) in ALP activity was found after 24 hours of treatment with the lowest dose (10(-9) mol/L), and a significant decrease in calcium deposition was found after 15 and 21 days of treatment (P < .05).


CONCLUSIONS
Clodronate increases the proliferation of MG63 osteoblast-like cells and decreases their differentiation capacity, generally at low doses, and modulates the expression of costimulatory molecules associated with immune function. Clodronate exerts its effect on osteoblasts by altering their physiology and impairing their repair capacity, which could be related to the development of BRONJ. However, further research is warranted to elucidate fully the mechanisms by which bisphosphonates can produce this disease.
Assistant Professor, Department of Stomatology, University of Granada, Granada, Spain.
Francisco Javier
FJ
Manzano-Moreno
Assistant Professor, Department of Nursing, Faculty of Health Sciences, University of Granada, Granada, Spain.
Javier
J
Ramos-Torrecillas
Assistant Professor, Department of Nursing, Faculty of Health Sciences, University of Granada, Granada, Spain.
Elvira
E
De Luna-Bertos
Associate Professor, Professor, Department of Stomatology, University of Granada, Granada, Spain.
Candela
C
Reyes-Botella
Associate Professor, Department of Nursing, Faculty of Health Sciences, University of Granada, Granada, Spain.
Olga
O
García-Martínez
Professor, Department of Nursing, Faculty of Health Sciences, University of Granada, Granada, Spain. Electronic address: crr@ugr.es.
Concepción
C
Ruiz
D000469:Alkaline Phosphatase / Q000378:metabolism; D000941:Antigens / Q000378:metabolism; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004002:Clodronic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D010006:Osteoblasts / Q000187:drug effects* / Q000276:immunology*; D013053:Spectrophotometry; D013997:Time Factors
D000941:Antigens; D050071:Bone Density Conservation Agents; D004002:Clodronic Acid; D000469:Alkaline Phosphatase