Lazáry Aron, Speer Gábor, Varga Péter Pál, Balla Bernadett, Bácsi Krisztián, Kósa János P, Nagy Zsolt, Takács István, Lakatos Péter
1st Department of Medicine, Semmelweis University, Korányi S. u. 2/a, Budapest, H-1083 Hungary.
J Orthop Res. 2008 May;26(5):601-7. doi: 10.1002/jor.20532.
Consequences of intradiscal cement leakage--often occurring after vertebral cement augmentation for the treatment of vertebral compression fractures--are still unknown. In this study, we have investigated the influences of vertebroplasty filler materials (polymethylmethacrylate-, calcium phosphate- and calcium sulfate-based bone cement) on isolated nucleus pulposus cells. Cell viability of cultured human nucleus pulposus cells were measured after treatment with vertebroplasty filler materials. Gene expression profile of selected genes was determined with quantitative real-time PCR. The widely used polymethylmethacrylate and calcium phosphate cement significantly decreased cell number in a dose- and time-dependent manner while calcium sulfate cement affected cell viability less. Expression of genes involved in matrix metabolism of nucleus pulposus--aggrecan, collagens, small proteoglycans--as well as important transcription factors have also significantly changed due to treatment (e.g., 2.5-fold decrease in aggrecan expression was determined in cultures due to polymethylmethacrylate treatment). Our results suggest that vertebroplasty filler materials--depending on the type of applied material--can accelerate the degeneration of nucleus pulposus cells resulting in a less flexible disc in case of intradiscal cement leakage. This process may increase the risk of a subsequent new vertebral fracture, the main complication of vertebral augmentation.
椎间盘内骨水泥渗漏的后果（常在椎体强化术治疗椎体压缩骨折后发生）仍不明确。在本研究中，我们调查了椎体成形术填充材料（聚甲基丙烯酸甲酯、磷酸钙和硫酸钙基骨水泥）对分离的髓核细胞的影响。在用椎体成形术填充材料处理后，测量培养的人髓核细胞的细胞活力。用定量实时聚合酶链反应测定选定基因的基因表达谱。广泛使用的聚甲基丙烯酸甲酯和磷酸钙骨水泥以剂量和时间依赖性方式显著减少细胞数量，而硫酸钙骨水泥对细胞活力的影响较小。由于处理，参与髓核基质代谢的基因（聚集蛋白聚糖、胶原蛋白、小蛋白聚糖）以及重要转录因子的表达也发生了显著变化（例如，在培养物中，由于聚甲基丙烯酸甲酯处理，聚集蛋白聚糖表达下降了2.5倍）。我们的结果表明，椎体成形术填充材料（取决于所用材料的类型）可加速髓核细胞退变，在椎间盘内骨水泥渗漏的情况下导致椎间盘灵活性降低。这一过程可能会增加随后发生新的椎体骨折的风险，而椎体强化术的主要并发症就是椎体骨折。
