AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland.
Eur Spine J. 2011 Jun;20(6):962-71. doi: 10.1007/s00586-010-1619-z. Epub 2010 Nov 18.
Cell therapy along with growth factor injection is currently widely investigated to restore the intervertebral disc. However, there is increasing evidence that transplanted unconditioned bone marrow-derived stromal cells (BMSCs) cannot thrive in the intervertebral disc "niche". Moreover, uncertainty exists with respect to the cell phenotype that would be suitable to inject. The intervertebral disc cell phenotype only recently has been started to be characterised using transcriptomics profiling. Recent findings suggest that cytokeratin 19 (KRT-19) could be used as a potential candidate marker for the intervertebral disc, or more specifically the nucleus pulposus cell (NPC) phenotype. We present in vitro cell culture data using alginate bead culture of primary human BMSCs exposed to the standard chondrogenic stimulus, transforming growth factor beta-1 (TGF-β), the growth and differentiation factor 5 and/or bovine NPCs to induce a potential "discogenic" pathway. Chondrogenic induction via TGF-β pathway provoked down-regulation of KRT-19 gene expression in four out of five donors after 18 days of culture, whereas KRT-19 expression remained unchanged in the "discogenic" groups. In addition, the ratio of aggrecan/collagen II gene expression showed a remarkable difference (of at least 3 magnitudes) between the chondrogenic stimulus (low ratio) and the discogenic stimulus (high ratio). Therefore, KRT-19 and aggrecan/collagen II ratio may be potential markers to distinguish chondrogenic from "discogenic" differentiation.
细胞治疗联合生长因子注射目前广泛用于修复椎间盘。然而，越来越多的证据表明，移植未经条件处理的骨髓基质细胞（BMSCs）不能在椎间盘“龛位”中茁壮成长。此外，适合注射的细胞表型也存在不确定性。最近才开始使用转录组谱分析来描述椎间盘细胞表型。最近的研究结果表明，细胞角蛋白 19（KRT-19）可用作椎间盘的潜在候选标志物，更具体地说是作为核髓核细胞（NPC）表型的标志物。我们介绍了体外细胞培养数据，使用原代人 BMSCs 的藻酸盐珠培养，将其暴露于标准的软骨形成刺激物转化生长因子β-1（TGF-β）、生长分化因子 5 和/或牛 NPCs 中，以诱导潜在的“椎间盘形成”途径。在经过 18 天的培养后，TGF-β 通路的软骨形成诱导导致五名供体中的四名 KRT-19 基因表达下调，而“椎间盘形成”组中的 KRT-19 表达保持不变。此外，聚集蛋白聚糖/胶原 II 基因表达的比值在软骨形成刺激（低比值）和椎间盘形成刺激（高比值）之间显示出显著差异（至少相差 3 个数量级）。因此，KRT-19 和聚集蛋白聚糖/胶原 II 比值可能是区分软骨形成与“椎间盘形成”分化的潜在标志物。
