, according to a study published in Immunology.
The study looked at the hearts of patients who died from COVID-19, the flu, and other causes. The findings could provide clues about why coronavirus has led to complications such as ongoing heart issues.
“We found a lot of DNA damage that was unique to the COVID-19 patients, which wasn’t present in the flu patients,” Arutha Kulasinghe, one of the lead study authors and a research fellow at the University of Queensland, Brisbane, Australia, told the Brisbane Times.
“So in this study, COVID-19 and flu look very different in the way they affect the heart,” he said.
Dr. Kulasinghe and colleagues analyzed the hearts of seven COVID-19 patients, two flu patients, and six patients who died from other causes. They used transcriptomic profiling, which looks at the DNA landscape of an organ, to investigate heart tissue from the patients.
Because of previous studies about heart problems associated with COVID-19, he and colleagues expected to find extreme inflammation in the heart. Instead, they found that inflammation signals had been suppressed in the heart, and markers for DNA damage and repair were much higher. They’re still unsure of the underlying cause.
“The indications here are that there’s DNA damage here, it’s not inflammation,” Dr. Kulasinghe said. “There’s something else going on that we need to figure out.”
The damage was similar to the way chronic diseases such as diabetes and cancer appear in the heart, he said, with heart tissue showing DNA damage signals.
Dr. Kulasinghe said he hopes other studies can build on the findings to develop risk models to understand which patients may face a higher risk of serious COVID-19 complications. In turn, this could help doctors provide early treatment. For instance, all seven COVID-19 patients had other chronic diseases, such as diabetes, hypertension, and heart disease.
“Ideally in the future, if you have cardiovascular disease, if you’re obese or have other complications, and you’ve got a signature in your blood that indicates you are at risk of severe disease, then we can risk-stratify patients when they are diagnosed,” he said.
The research is a preliminary step, Dr. Kulasinghe said, because of the small sample size. This type of study is often difficult to conduct because researchers have to wait for the availability of organs, as well as request permission from families for postmortem autopsies and biopsies, to be able to look at the effects on dead tissues.
“Our challenge now is to draw a clinical finding from this, which we can’t at this stage,” he added. “But it’s a really fundamental biological difference we’re observing [between COVID-19 and flu], which we need to validate with larger studies.”
A version of this article first appeared on WebMD.com.