Normal and osteoporotic human osteoblast behaviour after 1,25-dihydroxy-vitamin D(3) stimulation

In order to examine the effects of vitamin D on osteoblast function and to evaluate if osteoporotic and normal osteoblasts show a different behaviour in response to vitamin D, this report investigates the changes in osteocalcin production, after 1,25-dihydroxy-vitamin D3 stimulation of cultured osteoblasts derived from osteoporotic patients. Our results indicate an inadequate osteoblastic function in osteoporosis and demostrate that 1,25-dihydroxy-vitamin D3 can stimulate the metabolic activity of human osteoblasts in vitro. Considering that osteoporotic bone samples were representative of senile osteoporosis, our results may indicate a different metabolic phenotype in osteoporotic osteoblasts compared with normal osteoblasts. The increased osteocalcin production after 1,25-dihydroxy-vitamin D3 stimulation of osteoporotic osteoblasts suggests a reduced, but not absent, anabolic function in senile osteoporotic osteoblasts. The results of this study confirm the validity of vitamin D3 to treat senile osteoporosis and suggest the need of higher vitamin D3 intake in senile osteoporotic patients than in younger subjects.