Theranostics 2018; 8(19):5482-5500. doi:10.7150/thno.28315
Development of an Accurate and Proactive Immunomodulatory Strategy to Improve Bone Substitute Material-Mediated Osteogenesis and Angiogenesis
1. Department of Oral and Maxillofacial-Head and Neck Oncology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
2. Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology; National Clinical Research Center of Stomatology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
3. Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
4. Shanghai Key Laboratory of Tissue Engineering, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
5. Translational Research Centre of Regenerative Medicine and 3D Printing Technologies of Guangzhou Medical University, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong 510150, China.
6. China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, 310058, China.
*Authors have equally contributed to the work in this study.
Background: Treatment of large bone defects represents a major clinical problem worldwide. Suitable bone substitute materials are commonly required to achieve successful bone regeneration, and much effort has been spent to optimize their chemical compositions, 3D architecture and mechanical properties. However, material-immune system interactions are increasingly being recognized as a crucial factor influencing regeneration. Here, we envisioned an accurate and proactive immunomodulation strategy via delivery of IL-4 (key regulator of macrophage polarization) to promote bone substitute material-mediated regeneration.
Methods: Four different IL-4 doses (0 ng, 10 ng, 50 ng and 100 ng) were delivered into rat large cranial bone defects at day 3 post-operation of decellularized bone matrix (DBM) material implantation, and the osteogenesis, angiogenesis and macrophage polarization were meticulously evaluated.
Results: Micro-CT analysis showed that immunomodulation with 10 ng IL-4 significantly outperformed the other groups in terms of new bone formation (1.23-5.05 fold) and vascularization (1.29-6.08 fold), achieving successful defect bridging and good vascularization at 12 weeks. Histological analysis at 7 and 14 days showed that the 10 ng group generated the most preferable M1/M2 macrophage polarization profile, resulting in a pro-healing microenvironment with more IL-10 and less TNF-α secretion, a reduced apoptosis level in tissues around the materials, and enhanced mesenchymal stem cell migration and osteogenic differentiation. Moreover, in vitro studies revealed that M1 macrophages facilitated mesenchymal stem cell migration, while M2 macrophages significantly increased cell survival, proliferation and osteogenic differentiation, explaining the in vivo findings.
Conclusions: Accurate immunomodulation via IL4 delivery significantly enhanced DBM-mediated osteogenesis and angiogenesis via the coordinated involvement of M1 and M2 macrophages, revealing the promise of this accurate and proactive immunomodulatory strategy for developing new bone substitute materials.
Keywords: bone substitutes, immunomodulation, osteogenesis, angiogenesis, macrophages
Zheng Zw, Chen Yh, Wu Dy, Wang Jb, Lv Mm, Wang Xs, Sun J, Zhang ZY. Development of an Accurate and Proactive Immunomodulatory Strategy to Improve Bone Substitute Material-Mediated Osteogenesis and Angiogenesis. Theranostics 2018; 8(19):5482-5500. doi:10.7150/thno.28315. Available from http://www.thno.org/v08p5482.htm