Partial characterization of rat marrow stromal cells

Abstract

Fibroblast-like rat marrow stromal cell (CFU-F) cultures have been characterized in terms of their responsiveness to calciotropic hormones, metal ions, the nonsteroidal antiinflammatory drug, and by their putative paracrine role in the maintenance of active populations of osteoblasts at the marrow-bone interface. These studies indicate that CFU-Fs lack a complete osteoblast signature. Subconfluent CFU-Fs grown in the presence or absence of 10(-7) M dexamethasone lack receptors for PTH and calcitonin, and fail to show enhanced cAMP or cGMP responses to 10(-7) M 1-34 PTH (rat), or any evidence of osteocalcin production [+/- 10(-9) M 1,25-(OH)2D3]. Low concentrations of fluoride [10(-12) and 10(-9) M] stimulated CFU-F grown in vitro in serum-free media, though higher levels (10(-7) and 10(-6) M), inhibited growth in vivo and in vitro. Aluminum (10(-12)-10(-7) M) and ibuprofen (10(-7) M) did not alter normal growth patterns, indicating an action on bone cells more differentiated than CFU-Fs. Serum-free conditioned medium (CM) from control and ovariectomized (OVX)/OVX+ dihydrotachysterol-Rx rat CFU-F cultures was mitogenic for neonatal rat calvarial osteoblasts in vitro, but not for ROS 17/2.8 cells. The studies affirm the mesenchymal-like character of CFU-Fs and project their significant role in sustaining functional endosteal osteogenic cell populations.

Retrovirally transduced bone marrow stromal cells isolated from a mouse model of human osteogenesis imperfecta (oim) persist in bone and retain the ability to form cartilage and bone after extended passaging

“…24,29 The ceramics are composed of ions that are similar to bone mineral and are therefore osteoconductive. 25 When cells are introduced into the ceramic cubes, bone forms on the walls of the pores of the ceramics. 24 The bone that is formed in ceramics probably arises through the intramembranous osification, ie without the cartilage intermediate.…”

“…Among the factors that induce osteoblast differentiation are glucocoticoids, 24,25 bone morphogenetic proteins 23,26,27 and bFGF. 28 The transduced cells exhibited low alkaline phosphatase activity under basal conditions, rhBMP-2 treatment greatly enhanced alkaline phosphatase activity (Figure 2).…”

Nutritional Aspects of Aluminium Toxicity

“…Any or all of these factors may be operative in a clinical setting and it is uncertain at present which are most important and under what conditions. In addition, A1 may be responsible for de now bone formation (Smith, 1984;Galceran et al 1987;Blair et al 1989), their precursors (Simmons et al 1991) or, alternatively, further study.…”

Effects of aluminum on rat bone cell populations

“…Rat marrow grown for 10-12 days in serum-containing media has been shown to consist of 85% fibroblast-like cells, 10% macrophagic/granulocytic leukocytes, and 2.6% endothelial cells. The fibroblast-like cells proliferate in response to increasing doses of dexamethasone, but because they demonstrate no receptors for or a cAMP response to parathyroid hormone (PTH) and calcitonin, they do not exhibit osteoblast-like characteristics, that is, they remain in an undifferentiated osteoprogenitor state [19]. Such cells will form collagen-rich mineralizeable nodules on stromal cell feeder layers in medium containing 50 ~zg/ml ascorbic acid and 10 mM glycerophosphate (Fig.…”

“…The third and fourth 20 minutes digests release predominantly osteoprogenitor and osteoblast-like cells, and Table 1 shows that these cells exhibit a strong cAMP response to PTH for at least eight serial passages. These cells have been further characterized by their high alkaline phosphatase activity and their ability to produce osteocalcin and type I collagen [19,20]. …”