Fiegel Jennifer, Ehrhardt Carsten, Schaefer Ulrich Friedrich, Lehr Claus-Michael, Hanes Justin
Department of Chemical & Biomolecular Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, USA.
Pharm Res. 2003 May;20(5):788-96. doi: 10.1023/a:1023441804464.
The ability to optimize new formulations for pulmonary delivery has been limited by inadequate in vitro models used to mimic conditions particles encounter in the lungs. The aim is to develop a physiologically-relevant model of the pulmonary epithelial barrier that would allow for quantitative characterization of therapeutic aerosols in vitro.
Calu-3 human bronchial epithelial cells were cultured on permeable filter inserts under air-interfaced culture (AIC) and liquid-covered culture (LCC) conditions. Calu-3 cells grown under both conditions formed tight monolayers and appeared physiologically similar by SEM and immunocytochemical staining against cell junctional proteins and prosurfactant protein-C.
Aerosolized large porous particles (LPP) deposited homogeneously and reproducibly on the cell surface and caused no apparent damage to cell monolayers by SEM and light microscopy. However, monolayers initially grown under LCC conditions showed a significant decrease in barrier properties within the first 90 min after impingement with microparticles, as determined by transepithelial electrical resistance (TEER) measurements and fluorescein-sodium transport. Conversely, AIC grown monolayers showed no significant change in barrier properties within the first 90 min following particle application. A dense mucus coating was found on AIC grown Calu-3 monolayers, but not on LCC grown monolayers, which may protect the cell surface during particle impinging.
This in vitro model, based on AIC grown Calu-3 cells, should allow a more relevant and quantitative characterization of therapeutic aerosol particles intended for delivery to the tracheobronchial region of the lung or to the nasal passages. Such characterization is likely to be particularly important with therapeutic aerosol particles designed to provide sustained drug release in the lung.
用于模拟肺部颗粒所遇情况的体外模型不够完善，限制了优化肺部给药新制剂的能力。目标是开发一种与生理相关的肺上皮屏障模型，以便在体外对治疗性气雾剂进行定量表征。
在空气界面培养（AIC）和液体覆盖培养（LCC）条件下，将Calu-3人支气管上皮细胞培养在可渗透滤膜上。在这两种条件下生长的Calu-3细胞形成紧密单层，通过扫描电子显微镜（SEM）以及针对细胞连接蛋白和表面活性物质蛋白-C的免疫细胞化学染色显示，其在生理上相似。
雾化的大孔颗粒（LPP）均匀且可重复地沉积在细胞表面，通过SEM和光学显微镜观察，对细胞单层未造成明显损伤。然而，通过跨上皮电阻（TEER）测量和荧光素钠转运测定发现，最初在LCC条件下生长的单层在与微粒撞击后的最初90分钟内屏障特性显著下降。相反，AIC培养的单层在施加颗粒后的最初90分钟内屏障特性没有显著变化。在AIC培养的Calu-3单层上发现有致密的黏液涂层，而在LCC培养的单层上则没有，这可能在颗粒撞击期间保护细胞表面。
基于AIC培养的Calu-3细胞的这种体外模型，应该能够对旨在递送至肺气管支气管区域或鼻道的治疗性气雾剂颗粒进行更相关和定量的表征。对于设计用于在肺部提供持续药物释放的治疗性气雾剂颗粒而言，这种表征可能尤为重要。
