As the world continues to see the number of COVID-19 cases rise—and braces for a potential second wave—time is of the essence to scientifically investigate the coronavirus and discover approaches for tackling it.
We previously reported in Science First how cell-based models are playing important roles in helping us understand this virus. Now a new report in the science journal Nature is highlighting some of the latest discoveries that are being made about COVID-19 because of work with cell-based organoid models.
We have learned from patients that have been infected with COVID-19 that the virus can have a negative effect on organs, but whether this damage occurs directly from the virus or from secondary complications of infection remains elusive.
Many researchers are working with organoid models to help answer this question and to demonstrate where the virus travels in the body, which cells it infects and what kind of damage it causes. Organoids are good models for this type of research because they mimic human tissues and organs, are less expensive than animal models, and avoid the ethical issues that come from animal experimentation.
Because COVID-19 manifests itself as a respiratory ailment, work with organoids has helped researchers learn which specific types of cells in the lungs are targeted by the virus. Researchers have also discovered that the virus induces the production of proteins called cytokines. While some cytokine release is important during infection because it alerts the immune system of a problem, in some patients with COVID-19 infections, too many of these proteins are released too quickly, causing the immune system to overreact, leading to inflammation and other negative effects.
Using organoids, researchers have also determined how the coronavirus can travel from the lungs to other organs. COVID-19 can infect the cells lining the blood vessels, allowing viral particles to leak into the blood, circulate throughout the body and infect other organs.
We are learning through organoid-based research that kidney and liver cells can be directly infected with the virus, causing some cells to die. This may explain the damage observed in these organs in some COVID-19 patients.
Organoids are also being used to screen potential COVID-19 therapeutics. Human clinical trials have already been launched to test the efficacy of an existing cancer drug that has shown promise at suppressing COVID-19 in lung organoid models.
We commend researchers for choosing to work with human-relevant, animal-free models to help combat the coronavirus. We will continue to keep you posted on the progress that they are making in their efforts.
Mallapaty, S. “Mini organs reveal how the coronavirus ravages the body,” Nature, June 22, 2020.