The lung epithelial tissue barrier represents the main portal for entry of inhaled nanoparticles (NPs) into the systemic circulation. Thus great efforts are currently being made to determine adverse health effects associated with inhalation of NPs. However, to date very little is known about factors that determine the pulmonary translocation of NPs and their subsequent distribution to secondary organs. A novel two-step approach to assess the biokinetics of inhaled NPs is presented. In a first step, alveolar epithelial cellular monolayers (CMLs) at the air-liquid interface (ALI) were exposed to aerosolized NPs to determine their translocation kinetics across the epithelial tissue barrier. Then, in a second step, the distribution to secondary organs was predicted with a physiologically based pharmacokinetic (PBPK) model. Monodisperse, spherical, well-characterized, negatively charged gold nanoparticles (AuNP) were used as model NPs. Furthermore, to obtain a comprehensive picture of the translocation kinetics in different species, human (A549) and mouse (MLE-12) alveolar epithelial CMLs were exposed to ionic gold and to various doses (i.e., 25, 50, 100, 150, 200 ng/cm2) and sizes (i.e., 2, 7, 18, 46, 80 nm) of AuNP, and incubated post-exposure for different time periods (i.e., 0, 2, 8, 24, 48, 72 h). The translocation kinetics of the AuNP across A549 and MLE-12 CMLs was similar. The translocated fraction was (1) inversely proportional to the particle size, and (2) independent of the applied dose (up to 100 ng/cm2). Furthermore, supplementing the A549 CML with two immune cells, i.e., macrophages and dendritic cells, did not significantly change the amount of translocated AuNP. Comparison of the measured translocation kinetics and modeled biodistribution with in vivo data from literature showed that the combination of in vitro and in silico methods can accurately predict the in vivo biokinetics of inhaled/instilled AuNP. Our approach to combine in vitro and in silico methods for assessing the pulmonary translocation and biodistribution of NPs has the potential to replace short-term animal studies which aim to assess the pulmonary absorption and biodistribution of NPs, and to serve as a screening tool to identify NPs of special concern.

中文翻译：

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金纳米颗粒跨肺上皮组织屏障的转运：结合体外和计算机方法替代体内实验。

肺上皮组织屏障代表了吸入的纳米颗粒（NPs）进入体循环的主要入口。因此，目前正在做出巨大的努力来确定与吸入NP相关的不良健康影响。然而，迄今为止，关于决定NPs的肺易位及其随后分布于次级器官的因素知之甚少。提出了一种新颖的两步法评估吸入NP的生物动力学。第一步，将气液界面（ALI）上的肺泡上皮细胞单层（CML）暴露于雾化的NP中，以确定其跨上皮组织屏障的转运动力学。然后，在第二步中，使用基于生理学的药代动力学（PBPK）模型预测到次要器官的分布。单分散，球形，表征良好的，带负电的金纳米颗粒（AuNP）用作模型NP。此外，为了获得不同物种中易位动力学的全面情况，将人（A549）和小鼠（MLE-12）的肺泡上皮CML暴露于离子金和不同剂量（即25、50、100、150、200 ng / cm2）和大小（即2，Au，7、18、46、80 nm）的AuNP，并在暴露后孵育不同时间段（即0、2、8、24、48、72 h）。AuNP跨A549和MLE-12 CML的转运动力学相似。易位分数与颗粒大小成反比，（2）与所施加的剂量（最大100 ng / cm2）无关。此外，用两种免疫细胞，即巨噬细胞和树突状细胞补充A549 CML不会显着改变转位AuNP的量。将测得的转运动力学和建模的生物分布与文献中的体内数据进行比较表明，体外和计算机模拟方法的结合可以准确预测吸入/滴入的AuNP的体内生物动力学。我们结合体外和计算机方法评估NPs的肺易位和生物分布的方法，有可能取代旨在评估NPs的肺吸收和生物分布并用作鉴定工具的筛查工具的短期动物研究。特别关注的国家警察。