Human Periosteal Derived Stem Cell Potential: The Impact of age.

There is a great deal of interest in the understanding of possible age-related changes in Mesenchymal Stem Cells in view of their use for regenerative medicine applications. Given to the outmost standing of periosteum in bone biology and to probe data for a cell-based therapy promoting graft osseointegration in the elderly, we tried to identify specific aging markers or pattern of expression in human periosteal precursor cells. Immunohistochemical detection of Ki67 and p53, Nitric Oxide production and qRT- PCR of a selected gene panel for osteoblastic differentiation, bone remodeling and stemness were evaluated. We confirmed that both Ki67 and p53 are noteworthy indicators of senescence in human periosteal precursor cells and their expression significantly correlate with cell NO production. Moreover, cell age affects genes involved in bone remodeling, with a significant increase in interleukin-6 mRNA expression and receptor activator of nuclear factor kappa-B ligand/osteoprotegerin ratio. The analysis of mRNAs of genes involved in pluripotency regulation and self-renewal of stem cells, evidenced changes at least in part related to bone remodeling. We believe that this is the first study taking on age-related changes in human periosteal precursor cells, and paving the way toward new regenerative medicine strategies in bone aging and/or bone metabolic diseases.