New physiomimetic model for ARDS in vitro studies

Abstract

<b>Introduction:</b> The problem with conventional Acute Respiratory Distress Syndrome (ARDS) in vitro models is that they do not fully mimic the complex three-dimensional in vivo structure nor the mechanobiological signals to which cells are subjected owing to the cyclic mechanical stretch associated to spontaneous breathing or to mechanical ventilation. Our aim is to develop a physiomimetic in vitro model of ARDS based on 3D extracellular matrix hydrogels and lung-on-a-chip devices. <b>Methods:</b> Rat primary lung Mesenchymal Stem Cells (MSCs) were cultured within porcine lung extracellular matrix (ECM) hydrogels attached to a custom-made PDMS lung-on-a-chip device allowing for cyclic stretch (10%, 0.2Hz) and oxygen control (13%). Rat primary lung alveolar epithelial cells (AECs) were cultured on top of the hydrogels and subjected to a LPS challenge for 16h and to dexamethasone treatment for other 16h. Supernatants were collected, and multiplex ELISA analysis was performed for the main cytokines involved in ARDS. <b>Results:</b> The developed model responded to the LPS challenge by increasing significatively the values of IL-10, IL-6, IL-1β and TNF-α. The response was fainter than that showed by traditional in vitro models (2D culture), which could be explained by the presence of a more physiomimetic environment. After the application of dexamethasone, these cytokines tended to recover the values prior to the LPS hit. <b>Conclusions:</b> Results indicate that the developed physiomimetic model of ARDS-on-a-chip responds to a LPS challenge and partially recover the level of cytokines after anti-inflammatory drug treatment. Thus, the developed model opens the door for further in vitro research in the development of novel therapeutic strategies for ARDS treatment.