Université de Lyon, Université Jean Monnet, INSERM, SainBioSE, F-42023 Saint Etienne, France.
Université de Lyon, IMT Mines Saint-Etienne, Centre CIS, INSERM, SainBioSE, F-42023 Saint-Etienne, France.
Int J Hyg Environ Health. 2018 Mar;221(2):252-259. doi: 10.1016/j.ijheh.2017.11.002. Epub 2017 Nov 20.
Legionella are bacteria responsible for severe lung pathologies. However how they enter and are deposited within the respiratory tract remains poorly documented. Data using animal testing led to the establishment of mathematical models allowing the estimation of aerosol dispersion risks. But direct extrapolation to humans is questionable and experimental models more physiologically representative of the inhalation route are welcome. The aim of this study was to develop a model as close as possible to the human anatomy and physiology allowing determining the deposition pattern of aerosolized Legionella while limiting in vivo experiments. To that purpose, we adapted the chimeric respiratory tract model we previously developed. This original model consisted of a replica of the human upper respiratory airways made by additive manufacturing connected to ex vivo porcine lungs ventilated by passive expansion, as for humans in physiological conditions. These experiments didn't imply specific animal sacrifices as pigs were bred for human consumption and lungs were considered as wastes by the slaughterhouse. Fluorescent Legionella were aerosolized and visualized using Cellvizio Lab (probe-based confocal fluorescence microscope). Legionella were found in the whole respiratory tract. Broncho-alveolar lavages were also performed and the amount of Legionella reaching the thoracic region was quantified by culture and qPCR. Legionella were found preferentially in the left upper lobe compared to the right lower lobe. To our knowledge, it is the first time that experiments mimicking so closely human exposure by inhalation are performed while limiting animal experiments and providing a model for further Legionella infectious risk assessment.
军团菌是导致严重肺部疾病的细菌。然而，它们如何进入并沉积在呼吸道内仍未得到充分记录。使用动物试验获得的数据导致建立了数学模型，从而可以估计气溶胶分散风险。但是，直接外推到人类是值得怀疑的，并且更能代表吸入途径的生理代表性的实验模型是受欢迎的。本研究的目的是开发一种尽可能接近人体解剖结构和生理学的模型，以确定吸入性军团菌气溶胶的沉积模式，同时限制体内实验。为此，我们对我们之前开发的嵌合呼吸道模型进行了改编。这个原始模型由通过增材制造制作的人体上呼吸道复制品组成，该复制品通过被动膨胀与离体猪肺相连，与生理条件下的人类相同。这些实验不需要特定的动物牺牲，因为猪是为人类消费而饲养的，而肺部被屠宰场视为废物。用 Cellvizio Lab（基于探头的共聚焦荧光显微镜）对荧光军团菌进行气溶胶化并可视化。军团菌存在于整个呼吸道中。还进行了支气管肺泡灌洗，并通过培养和 qPCR 定量了到达胸部区域的军团菌数量。与右下叶相比，军团菌更倾向于左肺上叶。据我们所知，这是首次在限制动物实验的情况下，通过模拟吸入暴露来进行如此接近人类的实验，并为进一步的军团菌感染风险评估提供了模型。
