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标记细胞和外磁装置建立一种新型的细胞输送系统，以利于将来的临床应用。我们以骨髓间充质干细胞（mesenchymal stem cells，MSC）、神经前体细胞（neural progenitor cells，NSC）、自然杀伤细胞（natural killer cells，NK）等为细胞来源，建立了脂质体、磁珠、Ferumoxides（（Fe_2O_3）_n（FeO）_m）磁性标记细胞的方法。我们还制作了一个体外磁性装置，可用于人体临床应用。至于使用这种细胞递送系统进行软骨再生的体内研究，我们在猪髌骨中制造骨软骨缺损，并在外部磁力的影响下注射磁性标记的MSC。我们证实，即使在施加磁力后90分钟，注射的磁性标记细胞仍克服重力积聚到髌骨的软骨缺损处。在体外研究中，我们使用这种细胞递送系统将这些磁性标记的MSC聚集在从骨关节炎膝关节中取出的退变软骨片上。然后，将附着在软骨片上的那些聚集的细胞在软骨形成分化培养基中培养3周。培养3周后，在退化的软骨片上形成软骨样层，表明使用该细胞递送系统的软骨再生。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递送系统。这些研究的结果都是积极的，并发表在具有高影响因子的国际期刊上。

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.