New research is reviewing reports of delusions and brain fog, showing how the coronavirus attacks and kills brain cells to make more copies of itself.
Scientists around the world have shown in an online study published this week that has not yet been peer-reviewed or published in a journal that the virus breaks down brain cells by using their machinery to replicate.
In doing so, the infection appears to soak up oxygen from other brain cells near the one it entered and eventually kill them.
So far, the effects of the coronavirus on the brain don't seem to be what kills COVID-19 patients, but researchers say that untested infection in brain cells could be fatal.
A microscope image shows one of the lab-grown brain organoids that researchers infected with coronavirus to see how the virus took over the cell machinery and deprived of oxygen from nearby neurons. They also observe antibodies that prevent the virus from attaching (white) to a specific receptor while at work, suggesting that antibodies can prevent brain infection
Dr. Akiko Iwasaki, a Yale University immunologist, and her team used human brain organoids – tiny brains grown in the brain made from human stem cells – and mice to study the coronavirus invasion in real time.
In the organoids, SARS-CoV-2 not only took over the machinery of the brain cells into which it penetrated, but switched them to full speed.
"The hypermetabolic state is unique to the cells infected with SARS-CoV-2 and underscores the ability of SARS-CoV-2 to hijack the replication machinery of the host neuron," the authors of the study wrote.
While infected brain cells were busy pulling out more copies of the virus, it appeared to be poisoning the environment.
According to the new study, nearby cells go into a state of degradation – the so-called catabolic metabolism.
As suggested by researchers who did previous studies on COVID-19 and the brain, they found signs of oxygen starvation in and around neighboring cells.
The combined effects put these cells in their death spiral, which is scientifically proven by the "upregulation of cell death".
Brain cells, called neurons, communicate with each other using electrical signals.
In a healthy brain, these impulses move seamlessly and quickly through a vast network of neurons, like a massive, tightly-knit information highway.
But like potholes on a road, patches of dead cells interrupt the flow of information.
As a result, people with traumatic brain injuries or in the early stages of Alzheimer's disease may have "brain fog" as information about these dead zones falls in the brain.
Viral infections usually don't last long enough to cause the destruction of Alzheimer's. However, when a virus kills brain cells, as SARS-CoV-2 appears to be, it can also cloud perception or cause delirium.
And studies suggest that this is the case in a significant proportion of patients with COVID-19.
Research published in the New England Journal of Medicine in June found that 84 percent of COVID-19 patients developed neurological symptoms, such as headache, delirium, memory or attention problems, and burning or tingling sensations.
Another study found that about a third of the patients had neurological symptoms.
Patients who died of coronavirus showed signs of a dangerous form of brain swelling in autopsy studies. Some of their brain cells were also extinct.
Now that it is clear that the coronavirus can attack the brain, scientists need to figure out how it gets there and what to do about it. Both remain unclear.
In an encouraging development, however, the authors of the new study published on 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 infection of the laboratory-grown brain.
This is an encouraging sign that developing a vaccine or antibody treatment – if everyone proves safe in studies – could protect the brain from coronavirus.
(tagsToTranslate) Dailymail (t) Gesundheit (t) Coronavirus