November 9, 2020 -- As researchers learn more about COVID-19, they’ve seen reports from patients about unusual rashes, blood clots, and strokes, which could all be linked to damaged blood vessels.
Scientists are now looking at the vascular system, which includes arteries, veins, and capillaries, to monitor the various ways that the coronavirus attacks the body, according to NPR.
In particular, they’ve found that the virus seems to attack the endothelium, or the single layer of cells that line the inside of blood vessels. These cells prevent clotting, control blood pressure, and protect the body from invading pathogens.
“When the virus damages the inside of the blood vessel and shreds the lining, that’s like the ice after a hockey game,” William Li, a vascular biologist at the Angiogenesis Foundation, told NPR.
Li and a group of international researchers published a study this July that found lung tissue damage in COVID-19 patients. As compared with patients who died from the flu, the lung tissue of coronavirus patients had nine times as many small blood clots. They also saw what’s classified as “severe endothelial injury.”
“The surprise was that this respiratory virus makes a beeline for the cells lining blood vessels, filling them up like a gumball machine and shredding the cell from the inside out,” Li says. “We found blood vessels are blocked and blood clots are forming because of that lining damage.”
Scientists are finding similar blood clots and endothelial issues across the body. Several studies have linked COVID-19 with chilblains, or reddish-purple lesions on the toes, which has earned the moniker “COVID toes.” In a study in Spain, researchers found viral particles in the endothelial cells of patients with chilblains.
Now Li and other researchers are trying to understand how the coronavirus invades and damages these cells. The virus may directly attack the endothelium, or it may damage other cells first, which then shreds the blood vessels along the way.
"The effects in the brain, the blood clots in the lung and elsewhere in the legs, the COVID toe, the problem with the kidneys and even the heart,” Li said. Figuring out the puzzle could uncover why severe COVID-19 is linked with so many unusual complications across the body, from the brain to the toes.