COVID-19 is known to increase the risk of heart attack and stroke. The intense inflammation that occurs throughout the body in severe cases likely contributes to this increased risk. But it’s not clear whether SARS-CoV-2, the virus that causes COVID-19, also affects blood vessels directly.
To find out, an NIH-funded research team, led by Dr. Chiara Giannarelli at New York University School of Medicine, analyzed coronary artery tissue samples from eight people who died of COVID-19 between May 2020 and May 2021. Results appeared in Nature Cardiovascular Research on September 28, 2023.
The team found SARS-CoV-2 viral RNA in coronary artery tissue from all patients. They found more viral RNA in the arterial walls than in the surrounding fat tissue. Many of the infected cells were macrophages, a type of white blood cell that ingests pathogens. Samples with more macrophages had more viral RNA.
Macrophages also help remove cholesterol from blood vessels. When macrophages become laden with cholesterol, they are known as foam cells. Accumulation of foam cells within arteries forms plaques that are a hallmark of atherosclerosis. The team confirmed that SARS-CoV-2 could infect human macrophages and foam cells in a petri dish. The foam cells were much more susceptible to infection than the macrophages. This could explain why people with atherosclerosis are more vulnerable to COVID-19.