Regenerative medicine for musclo-skeltal system using autologous mesenchymal stem cell conjugated with magnet beads or magnet liposome

本研究的目的是利用磁性标记细胞和外部磁性装置建立新的细胞递送系统，为未来的临床应用奠定基础。我们已经使用了几种不同的细胞，如骨髓间充质干细胞(MSC)、神经前体细胞或自然杀伤细胞作为来源。首先，我们建立了使用脂质体、磁珠或铁氧化物((Fe_2O_3)_n(FeO)_m)对这些细胞进行磁性标记的方法。我们还制作了一种可用于人类临床应用的体外磁性装置。至于利用该细胞递送系统进行体内软骨再生的研究，我们在猪的膝盖骨中制造了骨软骨缺损，并在外加磁力的影响下注射了磁性标记的MSC。我们证实，即使在施加磁力90分钟后，注入的磁性标记细胞也在重力的作用下聚集到了髌骨的软骨缺损处。在体外研究中，我们利用该细胞递送系统将磁性标记的MSC聚集在退变的膝关节软骨上。然后，将积聚的细胞贴附在软骨片上，在软骨分化培养液中培养3周。经过3周的培养，在变性的软骨片上形成了类软骨层，表明该细胞输送系统可用于软骨再生。除了对软骨再生的几项研究外，我们还建立了用于脊髓损伤、骨缺损或恶性肿瘤的细胞输送系统。这些研究的结果都是积极的，并发表在影响因子较高的国际期刊上。

The purpose of this research project was to establish new cell delivery system using magnetically labeled cells and external magnetic device heading for future clinical application. We have used several different cells such as mesenchymal stem cells (MSC) from bone marrow, neural progenitor cells, or natural killer cells as cell source.First, we have established methods to label those cells magnetically using liposome, magnetic beads, or Ferumoxides ((Fe_2O_3)_n (FeO)_m). We also made an external magnetic device, which can be used for human clinical application.As for in vivo study for cartilage regeneration using this cell delivery system, we made osteochondral defects in the swine patella and injected magnetically labeled MSC under influence of external magnet force. We confirmed that the injected magnetically labeled cells were accumulated to the cartilage defect of the patella against gravity even 90 minutes after magnetic force application. In vitro study, we accumulated those magnetically labeled MSC on the degenerated cartilage piece taken from osteoarthritic knee using this cell delivery system. Then, those accumulated cells attached to the cartilage piece were cultured for 3 weeks in chondrogenic differentiation medium. After 3 weeks of culture, cartilage-like layers were formed on the degenerated cartilage piece indicating cartilage regeneration using this cell delivery system.Beside several researches for cartilage regeneration, we have established cell delivery system for spinal cord injury, bone defect, or malignant tumor. The results of those researches were all positive and were published in international journals, which have high impact factors.