Chen Zhenying, Bo Qitao, Wang Chao, Xu Yong, Fei Xiang, Chen Ru
The Center of Joint and Sports Medicine, Orthopedics Department, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China.
Department of Thoracic Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai, China.
J Nanobiotechnology. 2025 Apr 29;23(1):325. doi: 10.1186/s12951-025-03403-0.
Heterogeneous osteochondral regeneration remains a significant challenge due to the distinct microenvironments across the cartilage, calcified cartilage, and subchondral bone layers. The natural gradient of vascularization from the superficial to deep layers of osteochondral tissue plays a critical role in guiding the differentiation of bone marrow stem cells (BMSCs) into chondrocytes and osteoblasts. In this study, we propose a strategy for gradient heterogeneous osteochondral regeneration using cartilage organoids derived from single BMSCs, leveraging the natural vascularization gradient within osteochondral tissue. We successfully isolated BMSCs from rabbits and generated cartilage organoids via in vitro three-dimensional chondrogenic culture. To mimic the pro-vascular microenvironment, we introduced vascular endothelial growth factor, which promoted the hypertrophic differentiation of the cartilage organoids. We then prepared cartilage organoid/GelMA complexes, with or without the anti-vascular drug Axitinib, and implanted them subcutaneously in nude mice. The vascularized subcutaneous microenvironment induced osteogenic differentiation, while Axitinib treatment created an anti-vascular microenvironment, inhibiting osteogenesis and preserving chondrogenesis within the complexes. Both in vitro and in vivo data demonstrated the crucial role of the vascular microenvironment in regulating osteogenic differentiation of cartilage organoids. Finally, organoid/GelMA cylinders were implanted into a rabbit osteochondral defect, where the gradient vascularization at the defect site guided the organoids to differentiate into both cartilage and bone. This single BMSC-derived cartilage organoid approach enables precise gradient heterogeneous osteochondral regeneration, guided by the natural microenvironment within the osteochondral defect site, representing a significant advancement for clinical applications.
由于软骨、钙化软骨和软骨下骨层的微环境不同，异质性骨软骨再生仍然是一个重大挑战。骨软骨组织从浅层到深层的自然血管化梯度在引导骨髓干细胞（BMSCs）分化为软骨细胞和成骨细胞方面起着关键作用。在本研究中，我们提出了一种利用源自单个BMSCs的软骨类器官进行梯度异质性骨软骨再生的策略，利用骨软骨组织内的自然血管化梯度。我们成功地从兔子中分离出BMSCs，并通过体外三维软骨生成培养产生了软骨类器官。为了模拟促血管微环境，我们引入了血管内皮生长因子，其促进了软骨类器官的肥大分化。然后，我们制备了含有或不含有抗血管药物阿西替尼的软骨类器官/GelMA复合物，并将其皮下植入裸鼠体内。血管化的皮下微环境诱导成骨分化，而阿西替尼治疗则创造了一个抗血管微环境，抑制复合物内的成骨并保留软骨生成。体外和体内数据均表明血管微环境在调节软骨类器官成骨分化中的关键作用。最后，将类器官/GelMA圆柱体植入兔骨软骨缺损处，缺损部位的梯度血管化引导类器官分化为软骨和骨。这种源自单个BMSCs的软骨类器官方法能够在骨软骨缺损部位的自然微环境引导下实现精确的梯度异质性骨软骨再生，代表了临床应用的重大进展。
