Lung organoids: A new way to study human lung development and diseases

The pulmonary system is mainly comprised of the airways and the alveolar space. The complexity of its tissues and cells ensures the immune defense and gas exchange functions. Traditional in vitro cell experiments and animal models have been widely employed to elucidate the human lung development, physiology and pathogenesis. However, these models can not accurately recapitulate the human lung environment and the cell-to-cell crosstalk. Currently, lung organoids are the closest model to human lung system, and the in vitro lung model represented by lung organoids has become an accessible tool for investigating lung development, function and disease pathology. In this review, we introduce the main categories and research status of lung organoids, then further focus on the cultivation process and the unique application of lung organoids. Finally, we discuss the main limitations of culturing lung organoids.