Doryab Ali, Taskin Mehmet Berat, Stahlhut Philipp, Schröppel Andreas, Orak Sezer, Voss Carola, Ahluwalia Arti, Rehberg Markus, Hilgendorff Anne, Stöger Tobias, Groll Jürgen, Schmid Otmar
Comprehensive Pneumology Center Munich, Member of the German Center for Lung Research, Munich, Germany.
Helmholtz Zentrum München-German Research Center for Environmental Health, Institute of Lung Biology and Disease, Munich, Germany.
Front Bioeng Biotechnol. 2021 Jan 29;9:616830. doi: 10.3389/fbioe.2021.616830. eCollection 2021.
Evolution has endowed the lung with exceptional design providing a large surface area for gas exchange area (ca. 100 m) in a relatively small tissue volume (ca. 6 L). This is possible due to a complex tissue architecture that has resulted in one of the most challenging organs to be recreated in the lab. The need for realistic and robust lung models becomes even more evident as causal therapies, especially for chronic respiratory diseases, are lacking. Here, we describe the yclic ell-stretch (CIVIC) "breathing" lung bioreactor for pulmonary epithelial cells at the air-liquid interface (ALI) experiencing cyclic stretch while monitoring stretch-related parameters (amplitude, frequency, and membrane elastic modulus) under real-time conditions. The previously described biomimetic copolymeric BETA membrane (5 μm thick, bioactive, porous, and elastic) was attempted to be improved for even more biomimetic permeability, elasticity (elastic modulus and stretchability), and bioactivity by changing its chemical composition. This biphasic membrane supports both the initial formation of a tight monolayer of pulmonary epithelial cells (A549 and 16HBE14o) under submerged conditions and the subsequent cell-stretch experiments at the ALI without preconditioning of the membrane. The newly manufactured versions of the BETA membrane did not improve the characteristics of the previously determined optimum BETA membrane (9.35% PCL and 6.34% gelatin [w/v solvent]). Hence, the optimum BETA membrane was used to investigate quantitatively the role of physiologic cyclic mechanical stretch (10% linear stretch; 0.33 Hz: light exercise conditions) on size-dependent cellular uptake and transepithelial transport of nanoparticles (100 nm) and microparticles (1,000 nm) for alveolar epithelial cells (A549) under ALI conditions. Our results show that physiologic stretch enhances cellular uptake of 100 nm nanoparticles across the epithelial cell barrier, but the barrier becomes permeable for both nano- and micron-sized particles (100 and 1,000 nm). This suggests that currently used static assays may underestimate cellular uptake and transbarrier transport of nanoparticles in the lung.
进化赋予了肺卓越的设计，使其在相对较小的组织体积（约6升）中拥有用于气体交换的大表面积（约100平方米）。这得益于其复杂的组织结构，这也使得肺成为实验室中最难再造的器官之一。由于缺乏有效的治疗方法，尤其是针对慢性呼吸道疾病的治疗方法，因此对逼真且可靠的肺模型的需求变得更加明显。在此，我们描述了一种用于肺上皮细胞的循环细胞拉伸（CIVIC）“呼吸”肺生物反应器，该反应器可使肺上皮细胞在气液界面（ALI）经历循环拉伸，同时在实时条件下监测与拉伸相关的参数（幅度、频率和膜弹性模量）。我们尝试通过改变其化学成分来改进先前描述的仿生共聚BETA膜（5微米厚，具有生物活性、多孔且有弹性），使其具有更高的仿生渗透性、弹性（弹性模量和拉伸性）和生物活性。这种双相膜既支持在浸没条件下肺上皮细胞（A549和16HBE14o）紧密单层的初始形成，也支持随后在ALI条件下进行的细胞拉伸实验，而无需对膜进行预处理。新制造的BETA膜版本并未改善先前确定的最佳BETA膜（9.35%聚己内酯和6.34%明胶[重量/体积溶剂]）的特性。因此，使用最佳BETA膜定量研究了生理循环机械拉伸（10%线性拉伸；0.33赫兹：轻度运动条件）对肺泡上皮细胞（A549）在ALI条件下纳米颗粒（100纳米）和微粒（1000纳米）的尺寸依赖性细胞摄取和跨上皮转运的作用。我们的结果表明，生理拉伸增强了100纳米纳米颗粒跨上皮细胞屏障的细胞摄取，但该屏障对纳米和微米尺寸的颗粒（100和1000纳米）均变得具有渗透性。这表明目前使用的静态检测方法可能低估了肺中纳米颗粒的细胞摄取和跨屏障转运。
