COVID-19 can kill cardiomyocytes and prevent contraction

From the early days of the pandemic, COVID-19 has been associated with heart problems such as reduced ability to pump blood and arrhythmias. However, it remains an open question whether these problems are caused by a virus that infects the heart or by an inflammatory response to a viral infection elsewhere in the body. These details make sense in understanding the best ways to treat coronavirus infections that affect the heart.

A new study from the University of Washington School of Medicine in St. Louis provides evidence that heart damage in COVID-19 patients is caused by a virus that invades and replicates in cardiomyocytes, causing cell death and preventing myocardial contraction. .. Researchers may use stem cells to design heart tissue that models human infections to help study disease and develop possible treatments.

This study was conducted on February 26th Journal of the American College of Cardiology: Basic to Translational Science..

“In the early days of the pandemic, there was evidence that this coronavirus could cause heart failure or heart damage in generally healthy people, alerting the heart disease community,” said senior author Kory. J. Lavine, MD, PhD, Associate Professor said. medicine. “Even some college athletes who were allowed to return to competitive athletics after COVID-19 infection later had scarring in their hearts. Maybe this was due to a direct heart infection or systemic inflammation. There was debate as to whether it was due to a reaction. It is caused by a lung infection.

“Our study is unique in that it clearly shows that the virus infects the heart, especially cardiomyocytes, in patients with COVID-19 who develop heart failure.”

Lavine and his colleagues, including collaborators Michael S. Diamond, MD, PhD, Herbert S. Gasser, Medical Professor, Michael J. Greenberg, PhD, and Assistant Professor of Biochemistry and Molecular Biophysics, also use stem cells. A tissue that models how the human heart tissue contracts. By studying these cardiac tissue models, they determined that the viral infection not only killed cardiomyocytes, but also destroyed the muscle fiber units that cause myocardial contraction.

They also showed that this cell death and loss of myocardial fibers can occur without inflammation.

“Inflammation can be a second blow in addition to the damage caused by the virus, but inflammation itself is not the first cause of heart damage,” Ravine said.

While other viral infections have long been associated with heart damage, Labine said SARS-CoV-2, the virus that causes COVID-19, affects the heart, especially immune cells that respond to infections. Said to be unique. In COVID-19, immune cells called macrophages, monocytes, and dendritic cells control the immune response. For most other viruses that affect the heart, T cells and B cells of the immune system have emerged.

“COVID-19 causes a different immune response in the heart compared to other viruses, and we still don’t know what that means,” Ravine said. “In general, immune cells found in response to other viruses tend to be associated with relatively short-lived illnesses that are resolved with supportive care. However, immune cells found in patients with COVID-19 heart disease are associated with chronic illness. Tends to be related. Long-term impact. These are related and require further investigation to understand what is happening. “

Part of the reason why it is difficult to answer these questions about the causes of heart damage is the difficulty of studying heart tissue from COVID-19 patients. Researchers have been able to verify their findings by studying tissues from four COVID-19 patients with infection-related heart damage, but more research is needed.

To that end, Ravine and Diamond are working on a mouse model of heart injury. To emphasize the urgency of work, Ravien pointed out the insidious nature of heart damage that COVID-19 can cause.

“Even young people with very mild symptoms can later develop heart problems and limit their athletic performance,” said Ravine. “I want to understand what’s going on and be able to prevent and treat it. In the meantime, I’ll take the virus seriously and do my best to take precautions and stop the epidemic. There is no more pandemic because I want you to. For future preventable heart disease. “