Beresford J N, Graves S E, Smoothy C A
Medical Research Council Bone Research Laboratory, Nuffield Orthopaedic Centre, Headington, Oxford, United Kingdom.
Am J Med Genet. 1993 Jan 15;45(2):163-78. doi: 10.1002/ajmg.1320450205.
The identification of the factors which regulate the proliferation and differentiation of cells of the osteoblast lineage remains one of the major challenges in the field of bone cell biology. Although considerable progress has been made in the isolation and culture of cells of the osteoblast lineage from both animal and, more recently, human bone, uncertainties have persisted as to the extent to which these cell populations retain the ability to differentiate into functional osteoblasts in vitro. The formation in vitro of mineralized nodules that exhibit the morphological, ultrastructural and biochemical characteristics of embryonic/woven bone formed in vivo, represents the first evidence that the differentiation of functional osteoblasts can occur in cultures of isolated animal bone-derived cell populations. It is clear, however, that the culture conditions employed at present only permit a small number of cells to differentiate to the extent of being capable of organising their extracellular matrix into a structure that resembles that of bone. Moreover, it has generally been found that the reproducible mineralization of this extracellular matrix requires supplementation of the culture medium with mM concentrations of beta-GP, which raises doubts as to the physiological relevance of this process. The formation of nodules has also been observed in cultures of human bone-derived cells. As found in cultures of animal bone-derived cells, reproducible mineralization of these nodules will occur in the presence of beta-GP. We have shown, however, that in the presence of the long acting ascorbate analogue Asc-2-P, the formation and mineralization of nodules can occur in the absence of beta-GP. The nodules formed in human bone-derived cell cultures have yet to be characterized as rigorously as those formed in cultures of animal bone-derived cells and thus it remains to be shown that they resemble bone formed in vivo.
确定调节成骨细胞谱系细胞增殖和分化的因素仍然是骨细胞生物学领域的主要挑战之一。尽管在从动物以及最近从人骨中分离和培养成骨细胞谱系细胞方面已经取得了相当大的进展，但这些细胞群体在体外保持分化为功能性成骨细胞能力的程度仍存在不确定性。体外形成的矿化结节表现出体内形成的胚胎/编织骨的形态、超微结构和生化特征，这是功能性成骨细胞分化可以在分离的动物骨源细胞群体培养物中发生的首个证据。然而，很明显，目前使用的培养条件仅允许少数细胞分化到能够将其细胞外基质组织成类似骨结构的程度。此外，人们普遍发现，这种细胞外基质的可重复矿化需要在培养基中添加毫摩尔浓度的β-甘油磷酸酯（β-GP），这让人对该过程的生理相关性产生怀疑。在人骨源细胞培养物中也观察到了结节的形成。正如在动物骨源细胞培养物中所发现的，在β-GP存在的情况下，这些结节会发生可重复的矿化。然而，我们已经表明，在长效抗坏血酸类似物Asc-2-P存在的情况下，结节的形成和矿化可以在没有β-GP的情况下发生。人骨源细胞培养物中形成的结节尚未像动物骨源细胞培养物中形成的结节那样得到严格表征，因此仍有待证明它们类似于体内形成的骨。
