College of Veterinary Medicine, Western University of Health Sciences, Pomona, California.
College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado.
J Biomed Mater Res B Appl Biomater. 2018 Feb;106(2):501-511. doi: 10.1002/jbm.b.33864. Epub 2017 Feb 11.
Chitosan is attractive as a substrate for stem cell expansion because it improves stemness through formation of spheroids. Hypoxia has also been proposed as a strategy to enhance stemness and survival of stem cells after in vivo implantation. This study was therefore designed to evaluate the influence of hypoxia on chitosan-induced behavior of stem cells. Umbilical cord matrix-derived stem cells were cultured on chitosan film or standard plate under normoxia and hypoxia, for 3 and 7 days. Based on immunophenotyping, chitosan strongly suppresses the expression of CD90 and CD105 cell surface markers, changes partially reversed by combined exposure to hypoxia. Hypoxia generally increased the volume and number of spheroids formed on chitosan, but the cellularity of cultures on chitosan films remained lower than that of standard plates. After 7 days of culture, the expression of stemness related genes (Oct4, Sox2, and Nanog) was best stimulated by combined exposure to chitosan and hypoxia. Based on our results, conditioning stem cells for 7 days on chitosan films under hypoxic conditions is recommended to enhance the stemness of stem cells, and minimize cell loss due to lack of attachment on chitosan. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 501-511, 2018.
壳聚糖作为干细胞扩增的基质具有吸引力，因为它通过形成球体来提高干细胞特性。缺氧也被提议作为一种策略，以提高干细胞的干性和体内植入后干细胞的存活率。因此，本研究旨在评估缺氧对壳聚糖诱导干细胞行为的影响。脐带基质来源的干细胞在常氧和缺氧条件下分别在壳聚糖膜和标准平板上培养 3 天和 7 天。基于免疫表型，壳聚糖强烈抑制 CD90 和 CD105 细胞表面标志物的表达，这种表达部分通过联合缺氧暴露而逆转。缺氧通常会增加壳聚糖上形成的球体的体积和数量，但壳聚糖膜上培养物的细胞密度仍低于标准平板。培养 7 天后，联合壳聚糖和缺氧暴露最能刺激干性相关基因（Oct4、Sox2 和 Nanog）的表达。根据我们的结果，建议在缺氧条件下将干细胞在壳聚糖膜上培养 7 天，以增强干细胞的干性，并最大限度地减少因缺乏壳聚糖附着而导致的细胞丢失。©2017 年 Wiley 期刊，生物医学材料研究杂志 B：应用生物材料，106B：501-511，2018。
