Bone formation of human osteoblast-like cells in a three-dimensional cell culture: An in vitro model for studies of skeletal disorders

A three-dimensional (3-D) cell culture model was used for investigations of the osteogenic activity of human cell lines, established from skeletal tissues of healthy individuals and from patients presenting with osteoporosis, myositis ossificans, and osteosarcoma. This model facilitates bone formation by osteoblast-like cells in vitro and allows investigations of the osteogenic activity of osteoblasts. The cells were seeded on a sponge-like matrix of denatured collagen and cultured for a period of up to six weeks. Cells from bone tissues of healthy donors showed extracellular matrix production in areas of high cellular density. A cell culture, established from bone tissue of a patient presenting with osteoporosis, attached to the denatured collagen but showed very poor activity in producing extracellular matrix although the cells remained viable over the entire culture period. Cell cultures from biopsies of myositis ossificans and osteosarcomas formed large amounts of extracellular matrix with early signs of mineral deposition. Cells of the continuous osteosarcoma cell lines TE-85 and SAOS-2 attached to the denatured collagen but did not build up mineralizing osteoid. These data illustrate the potential of the 3-D cell culture model to investigate the biopathology of human bone-derived cells of different origin and from different skeletal disorders and to test factors or materials which can modulate bone cell activity and bone formation in a defined in vitro environment.