Since the start of the epidemic, Covid-19 has been associated with heart problems, including reduced blood pumping capacity and an irregular heartbeat.
The question was open whether these problems were caused by a virus infecting the heart, or an inflammatory response to viral infections elsewhere in the body. These details have implications for understanding the best way to treat Corona virus infection that affects the heart.
A new study from Washington University School of Medicine in St. Louis provides evidence that heart damage in “Covid-19” patients is caused by the virus invasion and its proliferation within the heart muscle cells, which leads to cell death and interference with the contraction of the heart muscle.
The researchers used stem cells to engineer heart tissue that is a model for human infection and could help study disease and develop possible treatments.
The study was published February 26 in the Journal of the American College of Cardiology: Basic to Translational Science.
Lead author Corrie J. Lavigne, MD and co-author of the study said: “Even some athletes who were allowed to return to competitive athletics after contracting COVID-19 later showed heart scars. There has been debate about whether this was due to a direct infection.” “For heart or due to a systemic inflammatory response from lung infection. Our study is unique because it definitively shows that in patients with Covid-19 who developed heart failure, the virus infects the heart, especially the heart muscle cells.”
Lavigne and his colleagues, including Dr. Michael S Diamond and Dr. Herbert S. Jacir, used stem cells to engineer tissues that determine how human heart tissue shrinks.
By studying these heart tissue models, they concluded that the viral infection not only kills the heart muscle cells, but also destroys the muscle fiber units responsible for the contraction of the heart muscle.
They also showed that cell death and loss of cardiac muscle fibers can occur even in the absence of inflammation.
“Inflammation can be a second blow to the damage the virus does, but inflammation itself is not the primary cause of heart injury,” Lavigne said.
Other viral infections have long been associated with heart damage, but Lavigne said that SARS-CoV-2 is unique in its effect on the heart, especially in 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 dominate.
Lavigne said, “Covid-19 causes a different immune response in the heart compared to other viruses, and we do not yet know what that means. In general, immune cells seen that respond to other viruses tend to be associated with a relatively short disease that is resolved with supportive care.” “What we see in heart patients in Covid-19 tends to be associated with a chronic condition that can have long-term consequences, so we will need more research to understand what is happening.”
Some of the reason for the difficulty of answering these questions related to the causation of heart damage is the difficulty in studying the heart tissue from “Covid-19” patients. The researchers were able to verify the validity of their findings by studying the tissues of four patients with “Covid-19” who received a heart injury linked to infection, but more research is needed.
Lavigne added, “Even young people who have very mild symptoms can develop heart problems at a later time which limits their ability to exercise. We want to understand what is happening so that we can prevent or treat it. In the meantime, we want everyone to take it.” This virus is taken seriously and that they do their best to take precautions and stop the spread, so that we do not have a larger epidemic of preventable heart disease in the future. ”
Source: Science Daily