Decrease in the mesenchymal stem-cell pool in the proximal femur in corticosteroid-induced osteonecrosis

We have evaluated bone-marrow activity in the proximal femur of patients wi th corticosteroid-induced osteonecrosis and compared it with that of patien ts with osteonecrosis related to sickle-cell disease and with a control gro up without osteonecrosis. Bone marrow was obtained by puncture of the femor al head outside the area of necrosis and in the intertrochanteric region. T he activity of stromal cells was assessed by culturing fibroblast colony-fo rming units (FCFUs), We found a decrease in the number of FCFUs outside the area of osteonecrosi s in the upper end of the femur of patients with corticosteroid-induced ost eonecrosis compared with the other groups. We suggest that glucocorticosteroids may also have an adverse effect on bon e by decreasing the number of progenitors. The possible relevance of this f inding to osteonecrosis is discussed.