STUDY QUESTION Can we reconstitute physiologically relevant 3-dimensional (3D) microengineered endometrium in-vitro model? SUMMARY ANSWER Our representative microengineered vascularised endometrium on-a-chip closely recapitulates the endometrial microenvironment that consists of three distinct layers including epithelial cells, stromal fibroblasts and endothelial cells in a 3D extracellular matrix in a spatiotemporal manner. WHAT IS KNOWN ALREADY Organ-on-a-chip, a multi-channel 3D microfluidic cell culture system, is widely used to investigate physiologically relevant responses of organ systems. STUDY DESIGN, SIZE, DURATION The device consists of five microchannels that are arrayed in parallel and partitioned by array of micropost. Two central channels are for 3D culture and morphogenesis of stromal fibroblast and endothelial cells. In addition, the outermost channel is for the culture of additional endometrial stromal fibroblasts that secrete biochemical cues to induce directional pro-angiogenic responses of endothelial cells. To seed endometrial epithelial cells, on Day 8, Ishikawa cells were introduced to one of the two medium channels to adhere on the gel surface. After that, the microengineered endometrium was cultured for an additional 5–6 days (total ∼ 14 days) for the purpose of each experiment. PARTICIPANTS/MATERIALS, SETTING, METHODS Microfluidic 3D cultures were maintained in endothelial growth Medium 2 with or without oestradiol and progesterone. Some cultures additionally received exogenous pro-angiogenic factors. For the three distinct layers of microengineered endometrium-on-a-chip, the epithelium, stroma and blood vessel characteristics and drug response of each distinct layer in the microfluidic model were assessed morphologically and biochemically. The quantitative measurement of endometrial drug delivery was evaluated by the permeability coefficients. MAIN RESULTS AND THE ROLE OF CHANCE We established microengineered vascularised endometrium-on-chip, which consists of three distinct layers: epithelium, stroma and blood vessels. Our endometrium model faithfully recapitulates in-vivo endometrial vasculo-angiogenesis and hormonal responses displaying key features of the proliferative and secretory phases of the menstrual cycle. Furthermore, the effect of the emergency contraception drug levonorgestrel was evaluated in our model demonstrating increased endometrial permeability and blood vessel regression in a dose-dependent manner. We finally provided a proof of concept of the multi-layered endometrium model for embryo implantation, which aids a better understanding of the molecular and cellular mechanisms underlying this process. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION This report is largely an in-vitro study and it would be beneficial to validate our findings using human primary endometrial cells. WIDER IMPLICATIONS OF THE FINDINGS Our 3D microengineered vascularised endometrium-on-a-chip provides a new in-vitro approach to drug screening and drug discovery by mimicking the complicated behaviours of human endometrium. Thus, we suggest our model as a tool for addressing critical challenges and unsolved problems in female diseases, such as endometriosis, uterine cancer and female infertility, in a personalised manner. STUDY FUNDING/COMPETING INTEREST(S) This work is supported by funding from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) to Y.J.K. (No. 2018R1C1B6003), to J.A. (No. 2020R1I1A1A01074136) and to H.S.K. (No. 2020R1C1C100787212). The authors report no conflicts of interest.

中文翻译：

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三维微工程血管化子宫内膜芯片

研究问题 我们能否重建生理相关的 3 维 (3D) 微工程子宫内膜体外模型？总结答案 我们的代表性微工程血管化子宫内膜片上以时空方式在 3D 细胞外基质中紧密概括了由三个不同层组成的子宫内膜微环境，包括上皮细胞、基质成纤维细胞和内皮细胞。已知的器官芯片是一种多通道 3D 微流控细胞培养系统，广泛用于研究器官系统的生理相关反应。研究设计、尺寸、持续时间 该装置由五个微通道组成，这些微通道平行排列并由微柱阵列分隔。两个中央通道用于基质成纤维细胞和内皮细胞的 3D 培养和形态发生。此外，最外面的通道用于培养额外的子宫内膜基质成纤维细胞，这些细胞分泌生化信号以诱导内皮细胞的定向促血管生成反应。为了播种子宫内膜上皮细胞，在第 8 天，将 Ishikawa 细胞引入两个培养基通道之一以粘附在凝胶表面上。之后，为了每次实验的目的，将微工程子宫内膜再培养 5-6 天（总共 ~ 14 天）。参与者/材料、设置、方法微流体3D培养物维持在内皮生长培养基2中，含有或不含雌二醇和孕酮。一些培养物还接受外源性促血管生成因子。对于芯片上微工程子宫内膜的三个不同层，上皮，对微流体模型中每个不同层的基质和血管特征以及药物反应进行了形态学和生化评估。通过渗透系数评估子宫内膜药物递送的定量测量。主要结果和机会的作用 我们建立了微工程血管化芯片上子宫内膜，它由三个不同的层组成：上皮、基质和血管。我们的子宫内膜模型忠实地概括了体内子宫内膜血管生成和激素反应，显示了月经周期增殖和分泌阶段的关键特征。此外，在我们的模型中评估了紧急避孕药左炔诺孕酮的作用，表明子宫内膜通透性增加和血管退化呈剂量依赖性。我们最终提供了用于胚胎植入的多层子宫内膜模型的概念证明，这有助于更好地理解这一过程背后的分子和细胞机制。大规模数据 不适用。局限性，谨慎的原因 本报告主要是一项体外研究，使用人类原代子宫内膜细胞验证我们的研究结果将是有益的。研究结果的更广泛意义 我们的 3D 微工程血管化子宫内膜芯片通过模仿人类子宫内膜的复杂行为，为药物筛选和药物发现提供了一种新的体外方法。因此，我们建议将我们的模型作为一种工具，以个性化的方式解决女性疾病（如子宫内膜异位症、子宫癌和女性不孕症）中的关键挑战和未解决的问题。研究资助/竞争兴趣这项工作得到了韩国政府 (MSIT) 资助的韩国国家研究基金会 (NRF) 资助给 YJK (No. 2018R1C1B6003)、JA (No. 2020R1I1A1A01074136) 和HSK（编号：2020R1C1C100787212）。作者说没有侵犯他的权益。