Concept: Researchers from the University of California San Diego (UCSD) have used adult stem cells to produce mini human lungs in lab dishes. Scientists intend to study how respiratory and infectious diseases including COVID-19 affect all of the cells that make up the human organ, thereby enabling the testing of new treatments.

Nature of Disruption: The first adult human ‘lung-in-a-dish’ model called lung organoids mimic both the upper and lower airway as well as specialized cells that line the alveoli. The lung organoids will help researchers to examine drug efficacy and toxicity, as well as to reject ineffective compounds at ‘Phase 0’ before human clinical trials begin. Researchers used adult stem cells taken from human lungs that had been surgically removed due to lung cancer to produce three lung organoid lines. They were able to maintain cells that make up both the upper and lower airways of human lungs, including specialist alveolar cells known as AT2 that help exchange oxygen and carbon dioxide. The scientists revealed that the upper airway cells are required for the virus to initiate infection, whereas the lower airway cells are important for the immune response. A separate group of computational researchers looked at the gene expression patterns of the organoids and compared them to patient records who died of the disease. They discovered that the mini-lungs behaved more like real-world infections than other models, such as those with only one type of cell or those created using other methods.

Outlook: COVID-19 can cause lung complications such as pneumonia and, in the most severe cases, acute respiratory distress syndrome (ARDS). The virus can damage the lungs, heart, and brain, which increases the risk of long-term health problems. But researchers do not have sufficient information to study the infection impact on body organs and its severity. Hence, UCSD scientists are embracing the emerging technologies to develop a miniature version of adult human organs like lungs to investigate damages caused by such respiratory and infectious diseases. They are planning to use the model to determine post-COVID complications such as lung fibrosis and begun drug testing to control viral infection from entry to replication to spread.