HUMAN BONE-CELL PROLIFERATION IN-VITRO DECREASES WITH HUMAN DONOR AGE

We have measured the effect of age on the rate of outgrowth of cells f rom human trabecular bone, using a quantitative dye-binding technique. In cultures supplemented with autologous serum, there were significan t negative correlations between the age of the donor and both the prop ortion of fragments from which outgrowths were seen after 7 days (r = -0.70; p < 0.001) and the total cell number after 14 days (r = -0.78; p < 0.005). The autologous serum supported greater cell proliferation than did fetal calf serum in all subjects regardless of age. Taken wit h previous observations that the in vitro growth kinetics of passaged human bone cells are independent of age, our results show that the num ber of proliferative precursor cells on trabecular-bone surfaces is hi gher in younger subjects. There is a marked decrease in precursor numb ers in the second and third decades of life to a level which is mainta ined into old age.