Suchergebnisse

Bing Xia,* Liangliang Huang,* Lei Zhu, Zhongyang Liu, Teng Ma, Shu Zhu, Jinghui Huang, Zhuojing Luo Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China *These authors contributed equally to this work Abstract: Schwann cell (SC) transplantation is an attractive strategy for spinal cord injury (SCI). However, the efficacy of SC transplantation has been limited by the poor migratory ability of SCs in the astrocyte-rich central nervous system (CNS) environment and the inability to intermingle with the host astrocyte. In this study, we first magnetofected SCs by polysialyltransferase-functionalized superparamagnetic iron oxide nanoparticles (PST/SPIONs) to induce overexpression of polysialylation of neural cell adhesion molecule (PSA-NCAM) to enhance SC migration ability, before manipulating the direction of SC migration with the assistance of an applied magnetic field (MF). It was found that magnetofection with PST/SPIONs significantly upregulated the expression of PSA-NCAM in SCs, which significantly enhanced the migration ability of SCs, but without preferential direction in the absence of MF. The number and averaged maximum distance of SCs with PST/SPIONs migrating into the astrocyte domain were significantly enhanced by an applied MF. In a 300 µm row along the astrocyte boundary, the number of SCs with PST/SPIONs migrating into the astrocyte domain under an MF was 2.95 and 6.71 times higher than that in the absence of MF and the intact control SCs, respectively. More interestingly, a confrontation assay demonstrated that SCs with PST/SPIONs were in close contact with astrocytes and no longer formed boundaries in the presence of MF. In conclusion, SCs with PST/SPIONs showed enhanced preferential migration along the axis of a magnetic force, which might be beneficial for the formation of Büngner bands in the CNS. These findings raise the possibilities of enhancing the migration of transplanted SCs in astrocyte-rich CNS regions in a specific direction and creating an SC bridge in the CNS environment to guide regenerated axons to their distal destination in the treatment of SCI. Keywords: Schwann cell, astrocyte, magnetic field, superparamagnetic iron oxide nanoparticles, spinal cord injury, cell orientation

Zhongyang Liu,1,* Shu Zhu,1,* Liang Liu,2,* Jun Ge,3,4,* Liangliang Huang,1 Zhen Sun,1 Wen Zeng,5 Jinghui Huang,1 Zhuojing Luo1 1Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 2Department of Orthopedics, No 161 Hospital of PLA, Wuhan, Hubei, 3Department of Orthopedics, No 323 Hospital of PLA, Xi'an, Shaanxi, 4Department of Anatomy, Fourth Military Medical University, Xi'an, Shaanxi, 5Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, People's Republic of China *These authors contributed equally to this work Abstract: Peripheral nerve repair is still challenging for surgeons. Autologous nerve transplantation is the acknowledged therapy; however, its application is limited by the scarcity of available donor nerves, donor area morbidity, and neuroma formation. Biomaterials for engineering artificial nerves, particularly materials combined with supportive cells, display remarkable promising prospects. Schwann cells (SCs) are the absorbing seeding cells in peripheral nerve engineering repair; however, the attenuated biologic activity restricts their application. In this study, a magnetic nanocomposite scaffold fabricated from magnetic nanoparticles and a biodegradable chitosan–glycerophosphate polymer was made. Its structure was evaluated and characterized. The combined effects of magnetic scaffold (MG) with an applied magnetic field (MF) on the viability of SCs and peripheral nerve injury repair were investigated. The magnetic nanocomposite scaffold showed tunable magnetization and degradation rate. The MGs synergized with the applied MF to enhance the viability of SCs after transplantation. Furthermore, nerve regeneration and functional recovery were promoted by the synergism of SCs-loaded MGs and MF. Based on the current findings, the combined application of MGs and SCs with applied MF is a promising therapy for the engineering of peripheral nerve regeneration. Keywords: peripheral nerve repair, magnetic nanoparticle, nanocomposite, magnetic field, Schwann cell, functional recovery

Jianbo Gao, 1 Bing Xia, 1 Shengyou Li, 1 Liangliang Huang, 2 Teng Ma, 1 Xiaowei Shi, 1 Kai Luo, 3 Yujie Yang, 1 Laihe Zhao, 1 Hao Zhang, 4 Beier Luo, 5 Jinghui Huang 1 1Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China; 2Department of Orthopaedics, The General Hospital of Central Theater Command of People's Liberation Army, Wuhan, People's Republic of China; 3Department of Orthopaedics, The 985th Hospital of the PLA Joint Logistics Support Force, Taiyuan, People's Republic of China; 4Department of Spinal Surgery, People's Hospital of Longhua District, Shenzhen, People's Republic of China; 5Department of Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai, People's Republic of China*These authors contributed equally to this workCorrespondence: Beier LuoDepartment of Orthopaedics, Changhai Hospital, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, People's Republic of ChinaTel/Fax +862131161700Email bear_luo@126.comJinghui HuangDepartment of Orthopaedics, Xijing Hospital, Fourth Military Medical University, 169 Changle West Road, Xi'an, Shaanxi 710032, People's Republic of ChinaTel/Fax +862984775275Email huangjh@fmmu.edu.cnPurpose: The clinical outcome of spinal cord injury is usually poor due to the lack of axonal regeneration and glia scar formation. As one of the most classical supporting cells in neural regeneration, Schwann cells (SCs) provide bioactive substrates for axonal migration and release molecules that regulate axonal growth. However, the effect of SC transplantation is limited by their poor migration capacity in the astrocyte-rich central nervous system.Methods: In this study, we first magnetofected SCs with chondroitinase ABC-polyethylenimine functionalized superparamagnetic iron oxide nanoparticles (ChABC/PEI-SPIONs) to induce overexpression of ChABC for the removal of chondroitin sulfate proteoglycans. These are inhibitory factors and forming a dense scar that acts as a barrier to the regenerating axons. In vitro, we observed the migration of SCs in the region of astrocytes after the application of a stable external magnetic field.Results: We found that magnetofection with ChABC/PEI-SPIONs significantly up-regulated the expression of ChABC in SCs. Under the driven effect of the directional magnetic field (MF), the migration of magnetofected SCs was enhanced in the direction of the magnetic force. The number of SCs with ChABC/PEI-SPIONs migrated and the distance of migration into the astrocyte region was significantly increased. The number of SCs with ChABC/PEI-SPIONs that migrated into the astrocyte region was 11.6- and 4.6-fold higher than those observed for the intact control and non-MF groups, respectively. Furthermore, it was found that SCs with ChABC/PEI-SPIONs were in close contact with astrocytes and no longer formed boundaries in the presence of MF.Conclusion: The mobility of the SCs with ChABC/PEI-SPIONs was enhanced along the axis of MF, holding the potential to promote nerve regeneration by providing a bioactive microenvironment and relieving glial obstruction to axonal regeneration in the treatment of spinal cord injury.Keywords: Schwann cells, astrocytes, magnetic field, superparamagnetic iron oxide nanoparticles, spinal cord injury, cell orientation

Zhongyang Liu,1,* Liangliang Huang,1,* Liang Liu,1,* Beier Luo,2,* Miaomiao Liang,3 Zhen Sun,1 Shu Zhu,1 Xin Quan,1 Yafeng Yang,1 Teng Ma,1 Jinghui Huang,1 Zhuojing Luo1 1Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 2Department of Orthopaedics, Changhai Hospital, Second Military Medical University, Shanghai, 3Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China *These authors contributed equally to this work Abstract: Schwann cells (SCs) are attractive seed cells in neural tissue engineering, but their application is limited by attenuated biological activities and impaired functions with aging. Therefore, it is important to explore an approach to enhance the viability and biological properties of SCs. In the present study, a magnetic composite made of magnetically responsive magnetic nanoparticles (MNPs) and a biodegradable chitosan–glycerophosphate polymer were prepared and characterized. It was further explored whether such magnetic nanocomposites via applied magnetic fields would regulate SC biological activities. The magnetization of the magnetic nanocomposite was measured by a vibrating sample magnetometer. The compositional characterization of the magnetic nanocomposite was examined by Fourier-transform infrared and X-ray diffraction. The tolerance of SCs to the magnetic fields was tested by flow-cytometry assay. The proliferation of cells was examined by a 5-ethynyl-2-deoxyuridine-labeling assay, a PrestoBlue assay, and a Live/Dead assay. Messenger ribonucleic acid of BDNF, GDNF, NT-3, and VEGF in SCs was assayed by quantitative real-time polymerase chain reaction. The amount of BDNF, GDNF, NT-3, and VEGF secreted from SCs was determined by enzyme-linked immunosorbent assay. It was found that magnetic nanocomposites containing 10% MNPs showed a cross-section diameter of 32.33±1.81 µm, porosity of 80.41%±0.72%, and magnetization of 5.691 emu/g at 8 kOe. The 10% MNP magnetic nanocomposites were able to support cell adhesion and spreading and further promote proliferation of SCs under magnetic field exposure. Interestingly, a magnetic field applied through the 10% MNP magnetic scaffold significantly increased the gene expression and protein secretion of BDNF, GDNF, NT-3, and VEGF. This work is the first stage in our understanding of how to precisely regulate the viability and biological properties of SCs in tissue-engineering grafts, which combined with additional molecular factors may lead to the development of new nerve grafts. Keywords: Schwann cell, magnetic field, nanocomposite, cell proliferation