Decreased DNA synthesis by cultured osteoblastic cells in eugonadal osteoporotic men with defective bone formation.

Abstract

To determine the osteoblastic dysfunction that may be involved in the pathophysiology of osteoporosis in men we have compared histomorphometric indices of bone formation with in vitro characteristics of osteoblastic cells isolated from the trabecular bone surface in 23 untreated men with eugonadal osteoporosis. In most patients (n = 14), trabecular bone loss resulted from decreased bone formation evidenced by a lower than normal osteoblast surface, double tetracycline labeled surface, bone formation rate, and mean wall thickness. In these patients, DNA synthesis by cultured osteoblastic cells was altered. The peak of 1314thymidine incorporation into DNA, the maximal DNA synthesis, and the area under the curve of cell proliferation were lower than the values in normal bone cells from age-matched controls. Parameters of bone cell growth were decreased in correlation with the extent of actively bone forming surfaces. By contrast, in patients (n = 9) with normal histomorphometric indices ofbone formation, bone cell proliferation in vitro was not different from normal. Parameters of osteoblastic differentiation in vitro such as osteocalcin production and alkaline phosphatase activity were normal in the two groups of patients. This study shows that the trabecular bone loss resulting from defective bone formation in eugonadal osteoporotic men is associated with a lower than normal proliferative capacity of osteoblastic cells lining the trabecular bone surface.

Increased bone formation and decreased osteocalcin expression induced by reduced Twist dosage in Saethre-Chotzen syndrome

“…Cell growth of Nl and M-Tw cells was evaluated by DNA synthesis and cell counting, as described (29). Briefly, cells plated at 10 4 cells/cm 2 were cultured in DMEM with 10% FCS for 7 days.…”

“…Cells were incubated with 0.8 µCi/well of [ 3 H]-thymidine on days 1 to 6. [ 3 H]-thymidine incorporation into DNA was determined in four aliquots by liquid-scintillation counting, and total DNA synthesis (cumulative peak of [ 3 H]-thymidine incorporation into DNA) was determined (29). In parallel cultures, cells were counted and reported as cell number per square centimeter.…”

Age-related changes in bone formation, osteoblastic cell proliferation, and differentiation during postnatal osteogenesis in human calvaria

“…At these time-points, the cell layer was collected by trypsinization, DNA was precipitated with thrichloracetic acid (TCA), the TCA-insoluble fraction was dissolved in NaOH, and [ 3 H]-thymidine incorporation into DNA was measured in three aliquots by liquid scintillation. The time-course of cell growth was evaluated in each culture obtained from individual subjects and parameters of cell growth (peak of incorporation and cumulative incorporation of [ 3 H]-thymidine into DNA) were obtained from the profile of DNA synthesis during the time-course study, as described previously [Marie et al, 1989[Marie et al, , 1991.…”

Endogenous GM-CSF is involved as an autocrine growth factor for human osteoblastic cells

“…Recent data indicate that the endosteal bone forming activity in humans is mainly dependent on the proliferative capacity of osteoblast precursor cells (Marie et al, 1989b(Marie et al, , 1991. Several mitogenic factors produced in the close proximity of bone by marrow and bone cells were shown to regulate osteoblastic cell proliferation and may, therefore, play a key role in controlling endosteal bone formation in humans (Goldring and Gcddring, 1990).…”