Hofmann A, Ritz U, Hessmann M H, Schmid C, Tresch A, Rompe J D, Meurer A, Rommens P M
Department of Trauma Surgery, Johannes Gutenberg University School of Medicine, Mainz, Germany.
Bone. 2008 May;42(5):894-906. doi: 10.1016/j.bone.2008.01.013. Epub 2008 Feb 9.
Recent studies have provided evidence that the number and proliferation capacity of bone marrow-derived mesenchymal stem cells, as well as the number of osteoprogenitor cells are reduced in patients with fracture non-unions. For fracture non-unions that do not heal after appropriate surgical intervention, the question arises as to what extent systemic cellular dysfunctions should be considered as being pathogenetic factors. For this purpose, we have examined the hypothesis that the cell function of osteoblasts isolated from patients with fracture non-unions may differ from those of normal control individuals in an identical and controlled in vitro situation. We analyzed the osteoblast cell viability, formation of alkaline phosphatase-positive (CFU-ALP) and mineralization-positive (CFU-M) colony forming units, as well as global differences of gene expression in osteoblasts from patients with fracture non-unions and from control individuals. We found that cell viability and CFU-M-formation were significantly reduced in non-union osteoblasts. This was accompanied by significant differences in osteoblast gene expression as revealed by Affymetrix-microarray analysis and RT-PCR. We identified a set of significantly down-regulated factors in non-union osteoblasts that are involved in regulation of osteoblast proliferation and differentiation processes (canonical Wnt-, IGF-, TGF-beta-, and FGF-signaling pathways). The results of the present study strongly support the hypothesis that cell viability, differentiation, and gene expression of osteoblasts may be altered in patients who develop recurrent and recalcitrant fracture non-unions. Proteins involved in Wnt-, IGF, TGF-beta-, and FGF-signaling pathways may be of particular interest and may unveil new potential therapies.
近期研究已提供证据表明，骨折不愈合患者的骨髓间充质干细胞数量及增殖能力，以及骨祖细胞数量均减少。对于经适当手术干预后仍未愈合的骨折不愈合病例，就应在何种程度上将全身细胞功能障碍视为致病因素这一问题随之而来。为此，我们检验了这样一种假说：在相同且可控的体外环境下，从骨折不愈合患者分离出的成骨细胞的细胞功能可能与正常对照个体的不同。我们分析了成骨细胞的细胞活力、碱性磷酸酶阳性（CFU-ALP）和矿化阳性（CFU-M）集落形成单位的形成，以及骨折不愈合患者和成骨细胞对照个体的成骨细胞基因表达的整体差异。我们发现，不愈合成骨细胞的细胞活力和CFU-M形成显著降低。这伴随着Affymetrix微阵列分析和逆转录聚合酶链反应所揭示的成骨细胞基因表达的显著差异。我们在不愈合成骨细胞中鉴定出一组显著下调的因子，它们参与成骨细胞增殖和分化过程的调控（经典Wnt、IGF、TGF-β和FGF信号通路）。本研究结果有力支持了这样一种假说：在发生复发性和顽固性骨折不愈合的患者中，成骨细胞的细胞活力、分化和基因表达可能发生改变。参与Wnt、IGF、TGF-β和FGF信号通路的蛋白质可能特别值得关注，并可能揭示新的潜在治疗方法。
