Severe acute respiratory distress syndrome (ARDS) associated with COVID-19 can cause damage to the heart even if the virus itself does not affect heart tissue.This finding comes from today’s research Circulation.

This study suggests that ARDS causes widespread inflammation in the body, leading to secondary cardiovascular complications.

For four years, clinicians and researchers have observed that COVID-19 leads to an increased risk of stroke, heart attack, and chest inflammation, but the mechanisms of damage were not understood.

“This is an important question, and finding the answer will open up a whole new understanding of the link between this severe lung injury and the types of inflammation that can lead to cardiovascular complications. ,” said Dr. Michelle Olive, associate director of National Heart Hospital. , in a press release from the Lung and Blood Institute, Institute. “Study also suggests that suppressing inflammation through treatment may help minimize these complications.”

Olive was not involved in this study.

The study was conducted by examining autopsy heart specimens from 21 COVID-19 patients who died from SARS-CoV-2-related ARDS and 33 patients who died from other causes. The study authors also used mice with SARS-CoV-2-associated ARDS to more closely examine the dynamics of cardiac immune cells. They also induced ARDS in mice without SARS-CoV-2 to compare cardiac findings.

Sends “shock waves” throughout the body

The authors found that in both humans and mice, ARDS causes remodeling of cardiac resident macrophages, leading to increased inflammation and decreased cardiac function. Macrophages are immune cells that normally keep tissues healthy, but if they multiply too quickly they can cause inflammation.

Although there was no direct damage to cardiac tissue, pulmonary infection with COVID-19 increased cardiac macrophages, resulting in increased numbers of cardiac macrophages in both humans and mice with SARS-CoV-2-induced ARDS. Heart problems were caused. Specifically, the researchers found higher rates of CCR2.⁺ Macrophages (CC chemokine receptor type 2 positive) from humans infected with the novel coronavirus were compared with those from humans who did not.

Experiments in mice that induced ARDS without a virus also showed an increase in macrophages and cardiac damage. In subsequent experiments, the authors found that treating mice exposed to virus-induced ARDS with tumor necrosis factor-neutralizing antibodies reduced both inflammation and the number of CCR2.⁺ macrophage.

This study shows that the immune system can cause distant damage to other organs after infection with the new coronavirus.

“What this study shows is that after infection with the coronavirus, the immune system causes severe inflammation throughout the body, which can cause distant damage to other organs. This is because the virus itself “This is in addition to the direct damage to the lung tissue,” he said. Matthias Nahrendorf, MD, PhD, senior author of the study and professor of radiology at Harvard Medical School.

“These findings can also be applied more generally, as our results suggest that severe infections can send shock waves throughout the body.”