A new study reported by Washington University School of Medicine in St. Louis provides evidence that COVID-19 patients’ heart damage is caused by the virus invading and replicating inside heart muscle cells, leading to cell death and interfering with heart muscle contraction. The researchers used stem cells to engineer heart tissue that models the human infection and could help in studying the disease and developing possible therapies.
Since early in the pandemic, COVID-19 has been associated with heart problems, including reduced ability to pump blood and abnormal heart rhythms. But it’s been an open question whether these problems are caused by the virus infecting the heart, or an inflammatory response to viral infection elsewhere in the body.
The researchers used stem cells to engineer heart tissue that models the human infection and could help in studying the disease and developing possible therapies. The study is published in the Journal of the American College of Cardiology: Basic to Translational Science.
“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.”
Lavine and his colleagues also used stem cells to engineer tissue that models how human heart tissue contracts. Studying these heart tissue models, they determined that viral infection not only kills heart muscle cells but destroys the muscle fiber units responsible for heart muscle contraction. They also showed that this cell death and loss of heart muscle fibers can happen even in the absence of inflammation.
Other viral infections have long been associated with heart damage, but Lavine said SARS-CoV-2, the virus that causes COVID-19, is unique in the effect it has on the heart, especially in the immune cells that respond to the infection. In COVID-19, immune cells called macrophages, monocytes and dendritic cells dominate the immune response. For most other viruses that affect the heart, the immune system’s T cells and B cells are on the scene.
Washington University School of Medicine in St. Louis has the news release.
