Can COVID-19 infect the brain? Organoids may help explain

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As researchers continue their quest for answers as to whether—and how—different organs may be infected by COVID-19, many of these researchers are turning to human-relevant organoid models, as there is “no ideal animal model that mimics how SARS-CoV-2 infection leads to COVID-19 in people,” according to a recent article in The Scientist.

While a lot of attention has been dedicated to the effects of coronavirus in the lungs due to the respiratory issues associated with infection, three recent studies using human brain organoid models have provided evidence that the coronavirus is able to infect and replicate in human neurons.

Given that those infected with the coronavirus have reported a range of neurological symptoms, including loss of taste and smell, hallucinations, and delirium, questions remain as to whether these symptoms are due to infections in neural tissues themselves or due to indirect effects based on other complications of the infection.

Researchers recently determined that the coronavirus efficiently infected cells of human brain organoid models and used the cells to make more copies of the virus. They further reported that many cells within the brain organoids died after exposure to the virus. Interestingly, however, the cells that died were not always the same ones that were infected. This would suggest that infected cells can damage neighboring cells. Researchers were also successful at blocking the entry of the virus into the cells by targeting the protein it uses to gain access to them.

At this time, however, it’s still not clear if coronavirus is able to infect patients’ brains. Autopsy analyses of COVID-19 patients have shown some signs of the virus in brain tissue, but none of the studies have reported evidence of the virus replicating there.

Yale University immunologist Akiko Iwasaki cautioned, “I definitely don’t want people to start panicking and thinking that this is a brain infection, causing brain infection in everybody…there’s no proof for that.” She noted that the study only demonstrates that COVID-19 is capable of infecting the brain and that further studies are needed.

NAVS commends 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 make in their efforts.

Zimmer, K. “SARS-CoV-2 can infect human brain organoids,” The Scientist, July 2020.