Effects of Bisphosphonates (Etidronate) on human alveolar bone derived osteoblasts

Bisphosphonates are potent inhibitors of bone resorption that are currently being used to treat metastatic bone diseases and osteoporosis. Following oral surgery procedures, recent reports have shown osteonecrosis associated within the oral cavity and especially of the jaws with patients receiving chronic bisphosphonate therapy. However, these effects have not been seen in long bone throughout the body. Objectives: To determine the effects of Etidronate and Vitamin D on the proliferation and differentiation of osteoblastic cells derived from human alveolar bone. Methods: Healthy human alveolar bone cells were cultured in alpha media, containing penicillin (100U/ml), streptomycin (100 µg/ml), antibiotic-antimycotic, L-Glutamine 4 mM, and 10% fetal calf serum. A 1,25(OH)2 Vitamin D concentration of 10-8 M was used in conjunction with Etidronate concentrations of 10-6 and 10-7 M to obtain a dose response. The cultures at 70% confluency, were detached by trypsinization and cultured in 24 well plates at a density of 200,000 cells/well in alpha media and 10% FCS. After 24 hours of incubation, the controlled and experimental cells were placed in fresh media with the appropriate Etidronate and/or Vitamin D concentrations. Following 24 and 48 hours, the cells were tested for proliferation with tritiated thymidine. Results: After 24 hours, both concentrations of Etidronate (10-6 and 10-7) without Vitamin D (10-8) lead to significant (p<0.01;ANOVA) increases in proliferation and Vitamin D (10-8) by itself lead to a significant decrease. After incubation periods of 48 hours, all treatments with the Etidronate and Vitamin D resulted in a decrease of cellular proliferation. Conclusions: Etidronate with and without Vitamin D has a temporal and dose dependent effect on the proliferation of alveolar bone derived osteoblastic cells.

Funding: Dr. Maxwell W. Burstein Summer Research Fellowship and the Deans Office Faculty Practice Fund