Osteoblast behaviour in the presence of bisphosphonates: Ultrastructural and biochemical in vitro studies

Objective A positive balance in bone remodelling is an important goal of bone metabol ism both in the presence of the osteoporotic processes characteristic of ag eing and, especially, of prosthetic implants. The aim of the present work w as to obtain new information about the initial steps of osteoblastic growth in an in vitro osteoblastic model in the presence of two bisphosphonates. Methods Experiments were performed with Alendronate and Neridronate, two molecules used in the therapy of osteoporosis. Since differentiating features into os teoblastic cells are known to parallel the presence in the cytoplasm of alk aline phosphatase and osteocalcin, we also carried out immunohistochemical typing. Results Good differentiation and osteoblastic activity were generally observed in t he cells in contact with these compounds, except for 10(-4) Neridronate, wh ere biochemical data clearly indicated its toxic effect on the cells. Conclusion The detection of osteoblastic markers associated with an ultrastructural pi cture of correct organellar morphology in our cultures further supports the hypothesis of a metabolically positive action of these molecules on osteob lasts.