Cigarette smoke inhibits osteogenic differentiation and proliferation of human osteoprogenitor cells in monolayer and three-dimensional collagen gel culture

Cigarette smoke is a risk factor not only for emphysema but also for other disorders characterized by deficient tissue repair, including osteoporosis. We hypothesized, therefore, that smoke might directly impair bone cell rep air processes. To evaluate this, bone marrow osteoprogenitor cells were iso lated from normal subjects and cultured in monolayer and in three-dimension al type I collagen gel culture. Human osteoprogenitor cells could be induce d to differentiate toward osteoblast-like cells in both culture conditions by osteogenic supplements. Under both culture conditions, cigarette smoke e xtract (CSE) inhibited the proliferation of osteoprogenitor cells in a conc entration-dependent manner. CSE also inhibited differentiation of osteoprog enitor cells toward osteoblast-like cells as assayed by alkaline phosphatas e activity and calcium incorporation into cell layer. Cells in monolayer cu lture were more sensitive to the effect of smoke than cells in three-dimens ional gel culture, Similar results were obtained with osteoblast-like cells derived from osteosarcomas. This study, therefore, demonstrates that cigar ette smoke may affect bone progenitor cells directly and in this manner may contribute to the development of osteoporosis.