Modulating the Barrier Function of Human Alveolar Epithelial (hAELVi) Cell Monolayers as a Model of Inflammation.

Abstract

The incidence of inflammatory lung diseases such as acute respiratory distress syndrome (ARDS) remains an important problem, particularly in the present time with the Covid-19 pandemic. However, an adequate in vitro test system to monitor the barrier function of the alveolar epithelium during inflammation and for assessing anti-inflammatory drugs is urgently needed. Therefore, we treated human Alveolar Epithelial Lentivirus-immortalised cells (hAELVi cells) with the pro-inflammatory cytokines TNF-α (25 ng/ml) and IFN-γ (30 ng/ml), in the presence or absence of hydrocortisone (HC). While TNF-α and IFN-γ are known to reduce epithelial barrier properties, HC could be expected to protect the barrier function and result in an anti-inflammatory effect. We investigated the impact of anti-inflammatory/inflammatory treatment on transepithelial electrical resistance (TEER) and the apparent permeability coefficient (Papp) of the low permeability marker sodium fluorescein (NaFlu). After incubating hAELVi cells for 48 hours with a combination of TNF-α and IFN-γ, there was a significant decrease in TEER and a significant increase in the Papp. The presence of HC maintained the TEER values and barrier properties, so that no significant Papp change was observed. By using hAELVi cells to study anti-inflammatory drugs in vitro, the need for animal experiments could be reduced and pulmonary drug development accelerated.