Song Jiawei, Hou Mengmeng, Guo Yajie, Peng Han, Liu Shuai, Zhu Jun, Wang Qi, Li Jipeng, Yi Chenggang, Li Huichen
Department of Digestive Surgery, Xijing Digestive Disease Hospital, Fourth Military Medical University, Xi'an, 710032, China.
Department of Plastic and Reconstructive Surgery, Xijing Hospital, Fourth Military Medical University, No. 15, Changle West Road, Xi'an, 710032, Shaanxi, China.
Aesthetic Plast Surg. 2025 Jan 6. doi: 10.1007/s00266-024-04645-3.
Adipose-derived mesenchymal stem cell-derived extracellular vesicles (ASCs-Exos) possess angiogenic potential, which can enhance the retention rate of fat grafts. Hypoxic preconditioning can augment their functionality. However, the optimal conditions for hypoxic preconditioning and the specific mechanisms by which it exerts its effects are not well defined. This study aimed to screen for the optimal hypoxic culture conditions for ASCs and to preliminarily elucidate the mechanisms by which they exert their effects.
Flow cytometry and TUNEL fluorescence staining were employed to determine the optimal oxygen concentration and culture duration for hypoxic preconditioning of ASCs-Exos. Subsequently, a mixture of human adipose tissue and hypoxic preconditioned ASCs-Exos was implanted into the subcutaneous fat of nude mice. At 4 and 12 weeks post-transplantation, the fat graft specimens were weighed, and hematoxylin and eosin (H&E) staining and immunohistochemistry were performed to examine the samples. The expression of CD31 was assessed to analyze the formation of neovascularization. The expression of miRNA in Exos was then detected, and the influence of ASCs-Exos derived miRNA-126 on the proliferative capacity of neovascularization was verified through an EDU fluorescence assay.
ASCs-Exos exhibited optimal performance when cultured under an oxygen concentration of 5% for 24 h. After transplantation of human adipose tissue mixed with hypoxic preconditioned ASCs-Exos for 4 to 12 weeks, the weight of fat grafts and the number of viable adipocytes in the hypoxic ASCs-Exos group were significantly higher than those in the control group (P < 0.05), with better adipocyte integrity and enhanced neovascularization capacity. Detection of miRNA derived from hypoxic preconditioned ASCs-Exos revealed that miRNA-126 demonstrated robust angiogenic and proliferative capabilities in both in vitro and in vivo experiments.
In summary, hypoxic preconditioning of ASCs-Exos at 5% oxygen for 24 h significantly enhances their angiogenic properties, thereby improving the viability and retention of fat grafts. The study elucidates miRNA-126 as a critical mediator of neovascularization and adipocyte survival, offering a promising avenue for enhancing the efficacy of ASCs-Exos in regenerative medicine.
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脂肪来源的间充质干细胞衍生的细胞外囊泡（ASCs-Exos）具有血管生成潜力，可提高脂肪移植的留存率。低氧预处理可增强其功能。然而，低氧预处理的最佳条件及其发挥作用的具体机制尚不清楚。本研究旨在筛选ASCs的最佳低氧培养条件，并初步阐明其作用机制。
采用流式细胞术和TUNEL荧光染色法确定ASCs-Exos低氧预处理的最佳氧浓度和培养时间。随后，将人脂肪组织与低氧预处理的ASCs-Exos混合物植入裸鼠皮下脂肪。在移植后4周和12周，称取脂肪移植标本重量，并进行苏木精-伊红（H&E）染色和免疫组织化学检查样本。评估CD31的表达以分析新生血管形成。然后检测Exos中miRNA的表达，并通过EDU荧光测定法验证ASCs-Exos衍生的miRNA-126对新生血管增殖能力的影响。
当在5%氧浓度下培养24小时时，ASCs-Exos表现出最佳性能。将人脂肪组织与低氧预处理的ASCs-Exos混合移植4至12周后，低氧ASCs-Exos组的脂肪移植重量和存活脂肪细胞数量显著高于对照组（P<0.05）,脂肪细胞完整性更好，新生血管生成能力增强。对低氧预处理的ASCs-Exos衍生的miRNA检测显示，miRNA-126在体外和体内实验中均表现出强大的血管生成和增殖能力。
综上所述，将ASCs-Exos在5%氧浓度下进行24小时的低氧预处理可显著增强其血管生成特性，从而提高脂肪移植的存活率和留存率。该研究阐明了miRNA-126是新生血管形成和脂肪细胞存活的关键介质，为提高ASCs-Exos在再生医学中的疗效提供了一条有前景的途径。
本期刊要求作者为每篇适用循证医学排名的投稿指定证据水平。这排除了综述文章、书评以及涉及基础科学、动物研究、尸体研究和实验研究的稿件。有关这些循证医学评级的完整描述，请参阅目录或作者在线指南www.springer.com/00266 。
