Study Shows That COVID Causes Heart Damage
Heart problems in COVID are caused by the virus invading heart cells and causing damage, according to a new study.
Heart problems such as arrhythmia and lack of pumping ability were associated with COVID even at the start of the pandemic. However, it was not clear whether these effects were caused by the virus, or whether it was due to the body’s inflammatory response in mounting a defence against the virus.
“Early on in the pandemic, we had evidence that this coronavirus can cause heart failure or cardiac injury in generally healthy people, which was alarming to the cardiology community,” said senior author Kory J Lavine, MD, PhD, an associate professor of medicine. “Even some college athletes who had been cleared to go back to competitive athletics after COVID-19 infection later showed scarring in the heart. There has been debate over whether this is due to direct infection of the heart or due to a systemic inflammatory response that occurs because of the lung infection.”
Dr Lavine, along with other researchers from the Washington University School of Medicine, engineered stem-cell derived tissue as a model for how human heart tissue contracts. Studying these heart tissue models, they came to the conclusion that the viral infection kills muscle cells as well as the muscle fibre units involved in heart muscle contraction. This cell death and muscle fibre destruction happened even without inflammation.
“Our study is unique because it definitively shows that, in patients with COVID-19 who developed heart failure, the virus infects the heart, specifically heart muscle cells,” Dr Lavine said. “Inflammation can be a second hit on top of the damage caused by the virus, but the inflammation itself is not the initial cause of the heart injury.”
While other viral infections have been linked to heart damage, SARS-CoV-2 is unique in that monocytes and dendritic cells dominate the immune response, while other viruses that damage the heart attract T and B cells.
“COVID-19 is causing a different immune response in the heart compared with other viruses, and we don’t know what that means yet,” Dr Lavine said. “In general, the immune cells seen responding to other viruses tend to be associated with a relatively short disease that resolves with supportive care. But the immune cells we see in COVID-19 heart patients tend to be associated with a chronic condition that can have long-term consequences. These are associations, so we will need more research to understand what is happening.”
Source: News-Medical.Net
Journal information: Bailey, A. L., et al. (2021) SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis. JACC: Basic to Translational Science. doi.org/10.1016/j.jacbts.2021.01.002.
