Verifying reports of delusions and brain fogs, new research reveals just how coronavirus attacks and kills brain cells to churn out more copies of itself.
Collaborating scientists around the globe have shown that the virus burglarizes brain cells, using their machinery to replicate, in a study posted online this week, which has not yet been peer-reviewed or published in a journal.
And in the process, the infection seems to suck up the oxygen from other brain cells near the ones it has invaded, eventually killing them.
So far, coronavirus’s effects on the brain don’t seem to be what is killing COVID-19 patients, but researchers say that an unchecked infection in cerebral cells could be deadly.
A microscope image shows one of the lab-grown brain organoids that researchers infected with coronavirus to see how the virus took over cell machinery and deprived nearby neurons of oxygen. They also observes antibodies that help to prevent the virus from latching onto a particular receptor at work (white), suggesting antibodies can prevent brain infection
Dr Akiko Iwasaki, a Yale University immunologist, and her team used human brain ‘organoids’ – tiny lab-grown brains made from human stem cells – and mice to study coronavirus’s invasion in real time.
In the organoids, SARS-CoV-2 not only took over the machinery of brain cells it invaded, it shifted them into high gear.
‘The hypermetabolic state is unique to the SARS-CoV-2 infected cells and highlights the ability of SARS-CoV-2 to hijack the host neuron machinery to replicate,’ the study authors wrote.
While infected brain cells were busy cranking out more copies of the virus, it seemed to poison the environment around it.
Nearby cells go into break down mode – called catabolic metabolism – according to the new study.
As suspected by researchers who have conducted previous studies on COVID-19 and the brain, they found signs of oxygen deprivation in and around those neighboring cells.
The combined effects sent these cells into their their death spiral, as evidenced by ‘upregulation of cell death’ processes, in scientific terms.
Brain cells, called neurons, communicate with one another through electrical signals.
In a healthy brain, these impulses move seamlessly and quickly through a vast network of neurons, like massive, intricately connected information superhighway.
But, like potholes on a road, patches of dead cells interrupt the flow of that information.
As a result, people with traumatic brain injuries or in the early stages of Alzheimer’s may have ‘brain fog,’ as information tumbles over these dead zones in the brain.
Viral infections don’t usually stick around long enough to cause the devastation that Alzheimer’s does, but if a virus is killing off brain cells, as SARS-CoV-2 seems to, this too can cloud cognition or cause delirium.
And studies suggest it has, for a significant portion of patients with COVID-19.
Research published in June in the New England Journal of Medicine found that as many as 84 percent of COVID-19 patients developed neurological symptoms, such s headache, delirium, trouble with memory or attention, and burning or prickling sensation.
Another study found that about a third of patients had neurological symptoms.
Patients who died of coronavirus were found to have signs of a dangerous form of brain swelling in autopsy studies. Some of their brain cells had died off too.
Now that it’s clear that coronavirus can attack the brain, scientists need to work out how it gets there, and what to do about it, both of which remain unclear.
However, in one encouraging development, the authors of the new study, published Wednesday, found antibodies against the infection in the cerebrospinal fluid of a COVID-19 patient.
When they exposed a brain organoid to these antibodies, the immune proteins successfully blocked the lab-grown brains from getting infected.
That’s an encouraging sign that a vaccine or antibody treatments being developed – if each proves safe in trials – could protect the brain from coronavirus.