To improve the results, UCLA researchers used a 3D printed silicone model from
Dr. Jason Hinman, assistant professor of neurology at the David Geffen School of Medicine at UCLA and lead author on the study, claimed that the flow directly affects ACE2 expression. In addition to Hinman, the study’s authors include neurologists at the Geffen School of Medicine, scientists from UC San Francisco and the Veterans Health Administration. The paper was published in Stroke (PDF).
UCLA researchers created the model using data from CT scans of blood vessels in a human brain. They then lined the inner surfaces of the models with endothelial cells, the type of cells that line human blood vessels. The models allowed the researchers to mimic the same forces that would act on real blood vessels during a Covid-19 infection.
To confirm whether the coronavirus rocking in the bloodstream can bind to ACE2 on endothelial cells in the brain, the researchers produced mock “virus” fat molecules that are occupied with the spike proteins that the coronavirus uses to bind to ACE2. Previous research showed that the coronavirus binds to endothelial cells in other organs, but it was not known if this also happened in the brain.
After creating the new model, the researchers confirmed that the particles actually interacted with the cells lining the blood vessel, mainly in the regions of the brain with higher ACE2 levels.
“This finding could explain the increased incidence of stroke in Covid-19 infections,” said Hinman.
Another discovery shows that when the scientists analyzed the genes that were activated in the endothelial cells after the coronavirus spike proteins had bound, they found that the activated genes were a specific set of immune response genes that Cells are found in the cerebral blood vessel, but not in endothelial cells from other organs in the body.
“There is a unique endothelial response of the brain to the virus that can be helpful in identifying patients at higher risk of stroke,” said Hinman.
The researchers intend to conduct follow-up studies with a live coronavirus in the 3D printed blood vessel model to further confirm the results of the current study and clarify which Covid-19 patients may be at higher risk of stroke.