Sasitorn Rungarunlert, Agricultural Biotechnology Center, H-2100 Gödöllö, Hungary.
World J Stem Cells. 2009 Dec 31;1(1):11-21. doi: 10.4252/wjsc.v1.i1.11.
Embryonic stem (ES) cells have the ability to differentiate into all germ layers, holding great promise not only for a model of early embryonic development but also for a robust cell source for cell-replacement therapies and for drug screening. Embryoid body (EB) formation from ES cells is a common method for producing different cell lineages for further applications. However, conventional techniques such as hanging drop or static suspension culture are either inherently incapable of large scale production or exhibit limited control over cell aggregation during EB formation and subsequent EB aggregation. For standardized mass EB production, a well defined scale-up platform is necessary. Recently, novel scenario methods of EB formation in hydrodynamic conditions created by bioreactor culture systems using stirred suspension systems (spinner flasks), rotating cell culture system and rotary orbital culture have allowed large-scale EB formation. Their use allows for continuous monitoring and control of the physical and chemical environment which is difficult to achieve by traditional methods. This review summarizes the current state of production of EBs derived from pluripotent cells in various culture systems. Furthermore, an overview of high quality EB formation strategies coupled with systems for in vitro differentiation into various cell types to be applied in cell replacement therapy is provided in this review. Recently, new insights in induced pluripotent stem (iPS) cell technology showed that differentiation and lineage commitment are not irreversible processes and this has opened new avenues in stem cell research. These cells are equivalent to ES cells in terms of both self-renewal and differentiation capacity. Hence, culture systems for expansion and differentiation of iPS cells can also apply methodologies developed with ES cells, although direct evidence of their use for iPS cells is still limited.
胚胎干细胞（ES 细胞）具有分化为所有胚层的能力，不仅为早期胚胎发育模型提供了巨大的希望，而且为细胞替代疗法和药物筛选提供了强大的细胞来源。ES 细胞形成类胚体（EB）是产生不同细胞谱系以进一步应用的常用方法。然而，传统技术，如悬滴或静态悬浮培养，要么本身无法进行大规模生产，要么在 EB 形成过程中和随后的 EB 聚集过程中对细胞聚集的控制有限。为了进行标准化的大规模 EB 生产，需要一个明确的扩大平台。最近，生物反应器培养系统中使用搅拌悬浮系统（旋转瓶）、旋转细胞培养系统和旋转轨道培养产生的流体动力条件下 EB 形成的新型情景方法允许大规模形成 EB。它们的使用允许连续监测和控制物理和化学环境，这是传统方法难以实现的。本综述总结了各种培养系统中多能细胞衍生的 EB 生产的现状。此外，本文还概述了高质量 EB 形成策略与体外分化为各种细胞类型的系统相结合，以应用于细胞替代疗法。最近，诱导多能干细胞（iPS 细胞）技术的新见解表明，分化和谱系决定不是不可逆的过程，这为干细胞研究开辟了新的途径。这些细胞在自我更新和分化能力方面与 ES 细胞相当。因此，iPS 细胞的扩增和分化培养系统也可以应用 ES 细胞开发的方法，尽管它们在 iPS 细胞中的应用的直接证据仍然有限。
