Development of Cellular Models for Osteoblast Response Study to Adipocytic Secretions in an Osteoporosis Context.

The recent studies suggest that secretions from medullary adipocytes are involved in the mechanisms of bone loss in osteoporosis (OP) through their actions on neighbouring osteoforming cells, the osteoblasts. The objective of the research is the development of new cellular models representing the aging skeleton to confirm this hypothesis. To this end, osteoblasts will be isolated from human bone fragments coming from femoral heads discarded during total hip replacement surgery. The osteoblastic response to secreted factors released from medullary adipocytes of commercial origin will be analysed using conditioned media incubations. This phenotypic response will be quantified for each subject through the analysis of gene expression levels. Inter-subject phenotype variations will be related to bone density and microarchitecture data obtained by X-ray microtomography. This will assess the existence of a correlation between the osteoblast response to adipocyte secretions and the degree of osteoporosis of the subject from whom the cells are derived.