Yujie Wang

Introduction: Exosomes derived from M2 macrophages (M2-Exos) exhibit tremendous potential for inducing tissue repair and regeneration. Herein, this study was designed to elucidate the biological roles of M2-Exos in regenerative endodontic therapy (RET) compared with exosomes from M1 macrophages (M1-Exos). Methods: The internalization of M1-Exos and M2-Exos by dental pulp stem cells (DPSCs) and human umbilical vein endothelial cells (HUVECs) was detected by uptake assay. The effects of M1-Exos and M2-Exos on DPSC and HUVEC behaviors, including migration, proliferation, odonto/osteogenesis, neurogenesis, and angiogenesis were determined in vitro. Then, Matrigel plugs incorporating M2-Exos were transplanted subcutaneously into nude mice. Immunostaining for vascular endothelial growth factor (VEGF) and CD31 was performed to validate capillary-like networks. Results: M1-Exos and M2-Exos were effectively absorbed by DPSCs and HUVECs. Compared with M1-Exos, M2-Exos considerably facilitated the proliferation and migration of DPSCs and HUVECs. Furthermore, M2-Exos robustly promoted ALP activity, mineral nodule deposition, and the odonto/osteogenic marker expression of DPSCs, indicating the powerful odonto/osteogenic potential of M2-Exos. In sharp contrast with M1-Exos, which inhibited the neurogenic capacity of DPSCs, M2-Exos contributed to a significantly augmented expression of neurogenic genes and the stronger immunostaining of Nestin. Consistent with remarkably enhanced angiogenic markers and tubular structure formation in DPSCs and HUVECs in vitro, the employment of M2-Exos gave rise to more abundant vascular networks, dramatically higher VEGF expression, and widely spread CD31⁺ tubular lumens in vivo, supporting the enormous pro-angiogenic capability of M2-Exos. Conclusions: The multifaceted roles of M2-Exos in ameliorating DPSC and HUVEC functions potentially contribute to complete functional pulp–dentin complex regeneration.

牙髓炎、牙周炎、颌骨缺损及颞下颌关节损害是临床常见的口腔颌面部疾病，然而传统治疗手段无法有效恢复受损组织的结构和功能。因具有良好的生物相容性、生物降解性、抗氧化性、抗炎活性和广谱抗菌性，壳聚糖基水凝胶在口腔组织工程领域展现出广阔的应用前景。季铵化、羧甲基化、磺化是改善壳聚糖基水凝胶理化性质及生物学功能常见的化学修饰策略，通过携载多孔性微球或纳米颗粒构建水凝胶复合体系能实现多种药物或生物活性因子的局部序贯递送，为实现缺损组织有序再生奠定坚实基础。化学交联法常用于制备不可逆永久性壳聚糖凝胶，而物理交联法有助于形成可逆性凝胶网络。作为适宜的生物支架材料，目前多种壳聚糖基水凝胶协同干细胞、生长因子或胞外体移植已应用于口腔软硬组织缺损再生修复的探索中，并在促进牙髓-牙本质复合体、牙骨质-牙周膜-牙槽骨复合体、颌骨再生和软骨再生方面获得显著进展。然而，壳聚糖基水凝胶的临床转化应用仍面临诸多挑战。未来可致力于开展基于口腔内复杂微环境的体内研究，并将壳聚糖基水凝胶与多种不同的活性因子、生物材料和先进生物制造技术相结合以实现多层次全面口腔组织再生。