ADULT HUMAN BONE-CELLS FROM JAW BONES CULTURED ON PLASMA-SPRAYED OR POLISHED SURFACES OF TITANIUM OR HYDROXYLAPATITE DISCS

Adult human bone cells isolated from jaw bone biopsies were cultured e ither on Thermanox(R) coverslips or on polished or plasma-sprayed surf aces of titanium or hydroxylapatite and the levels of their various me tabolic functions were compared after 2 and 5 days of staying in cultu re. Thus, jaw bone cells grown on hydroxylapatite proliferated very li ttle, while expressing discrete levels of alkaline phosphatase activit y and of osteocalcin secretion into the growth medium. On the other ha nd, bone cells seeded onto titanium surfaces proliferated much more in tensely than those on Thermanox(R), besides expressing alkaline phosph atase (very intensely after 5 days) and secreting osteocalcin. Thus, b oth kinds of titanium surfaces greatly enlarged the size of both popul ations of preosteoblastic precursors and of pre-osteoblasts in vitro, but plasma-sprayed titanium surfaces elicited, between day 2 and 5 in culture, greater increases in bone cell numbers markedly enhancing the ir proliferative and alkaline phosphatase activities, along with their osteocalcin secretion into the growth medium, and thus favouring the expression of the mature osteoblastic phenotype. These preliminary fin dings show that studies correlating the physical surface features of v arious biomaterials with the corresponding expression of specific diff erentiation markers by the bone cells cultured on these same surfaces can provide information relevant to the clinical application of biomat erials.