As reported on October 30, 2020, scientists have watched the processes how the novel coronavirus attacks primarily the lungs and its subsequent impacts in real time with the help of a lung model developed in the lab. These findings were published in two research papers in the journal Cell Stem Press, by South Korean and UK researchers, including University of Cambridge, Duke University, and University of North Carolina. For this purpose, the scientists developed ‘mini lungs,’ or lung organoids in the lab, grown from the stem cells that repair the deepest portions of the lungs where SARS-CoV-2 attacks, i.e., AT2 cells, and infected them with SARS-CoV-2 to watch the battle between the lung cells and the virus in real time.
The scientists observed that the virus damages the alveoli in the infected lungs, which are balloon-like air sacs that take up the oxygen (O) we breathe in and the carbon dioxide (CO2) we breathe out. The damaged alveoli sacs causes pneumonia and acute respiratory distress, and ultimately leads to death in Covid-19.
The scientists from the UK and South Korea reprogrammed the AT2 cells back to their earlier ‘stem cell’ stage, which grew self-organising, alveolar-like 3D structures that mimic the behaviour of key lung tissues. The virus began to replicate rapidly when the 3D models were exposed to SARS-CoV-2. Cells began to produce interferons-proteins that act as warning signals to neighbouring cells in six hours. However, the cells started fighting back after 48 hours. Some of the alveolar cells began to disintegrate after 60 hours from infection, ultimately leading to damage of cells and their death.
In the second study, led by cell biologist Purushothama Rao Tata, Duke University, the researchers got a single lung cell to multiply into thousands of copies and create a structure resembling breathing tissues of the human lung. When the model was infected with the virus, it showed an inflammatory response. Besides that, the researchers also witnessed the cytokine storm—the hyper reaction of immune molecules, launched by the lungs to fight the infection.
Courtesy: Indian Express