In a new study led by the University of Washington School of Medicine, researchers demonstrate that SARS-CoV-2 – the pathogen behind COVID-19 disease – can enter the brain of mice, just like many other viruses before it.
People who develop COVID-19 often experience intense bodily inflammation called a cytokine storm, which results from the immune system’s overreaction to the virus and its related proteins. This causes brain fog, trouble concentrating, fatigue, and other cognitive issues.
Published in Nature Neuroscience, the study provides evidence that S1 – the spike protein of SARS-CoV-2, often depicted as the red arms of the virus in online images – is capable of crossing the blood-brain barrier and causing a series of toxic reactions in brain tissue.
The discovery was made by co-author WIlliam A. Banks, who is a long-time researcher of the blood-brain barrier in relation to Alzheimer’s, obesity, diabetes, and HIV, noticing that gp 120 – the binding protein of HIV-1 – functions very similarly to S1.
“We know that when you have the COVID infection you have trouble breathing and that’s because there’s infection in your lung, but an additional explanation is that the virus enters the respiratory centres of the brain and causes problems there as well,” said Banks.
Experiments also showed that men are more likely to develop severe illness than women because of faster transport of S1 in the olfactory bulb – a neural structure responsible for the sense of smell – and the kidneys.
According to Banks, these findings send a very clear message to those who don’t take the pandemic seriously:
“You do not want to mess with this virus. Many of the effects that the COVID virus has could be accentuated or perpetuated or even caused by virus getting in the brain and those effects could last for a very long time.”