Draft:In vitro lung models

In vitro models rely on animal or human cells sourced from cell lines, donors, or tissues. While these models were originally two-dimensional (2D), advancements like organ-on-chip and organoid technologies now allow for three-dimensional (3D) cell cultures that more accurately mimic physiologic conditions. These advanced models are powerful tools and can potentially replace less effective animal studies.

The lung is a highly complex organ with intricate physiology and structure, making it challenging to replicate in in vitro models. One distinct aspect of culturing pulmonary epithelial cells is the air-liquid interface (ALI), which closely mimics in vivo conditions. Typically, Transwell inserts are used to culture pulmonary epithelial cells, starting under submerged conditions and then to ALI.

Advanced in vitro lung models

The lung is a dynamic organ where pulmonary cells constantly experience mechanical forces. Yet, most lung cell models are designed under static conditions. To address the limitations of static culture models, lung-on-a-chip devices were developed. These lung chips can partially replicate the structure and function of the human lung and support the growth of lung cells under ALI conditions and dynamic environments, including cyclic mechanical stretching and fluid shear stress.

So far, various lung chips (e.g., alveolar and airway models) have been utilized to study the (patho)physiology of a range of diseases, from single-cell interactions to tissue-level responses, including bacterial and viral infections, pulmonary edema, fibrosis, and chronic obstructive pulmonary disease (COPD). These models have also been adapted for aerosol drug delivery, allowing researchers to study the behaviour of inhaled drugs and particles in the respiratory tract.