Researchers link miRNAs to heart attack risk

This week circulating cells have been linked to heart attacks and now microRNAs--fragments of non-coding genetic material--found in the blood show potential as a screening tool to predict imminent heart attacks. The researchers, from Intermountain Medical Center in Murray, UT, looked for traces of 6 known miRNA biomarkers in blood samples from 85 cardiac patients. The blood samples included ones taken up to a week before a heart attack or within 36 hours of having had a heart attack. Other samples were from healthy patients or people with heart problems but no sign of a heart attack.

In patients who would go on to have a heart attack within a week, levels of three of the miRNAs (miR-122, miR-145 and miR-375) were lower than in the other groups, with miR-122 reduced to the greatest extent. While the 6 biomarkers used were already associated with patients who had already had a heart attack, this was the first time that these miRNAs have been linked with heart attack risk in patients that appeared healthy. The results were presented at the American College of Cardiology's 61st Annual Scientific Session.

MiRNAs are used as "switches" for genes, and these results could help pinpoint which genes might be linked with heart attacks.

"We don't know exactly which genes are controlled by these microRNAs, but this study gives us a good starting point for looking more deeply into the ways they influence the heart," says John Carlquist, director of Intermountain Healthcare's Cardiovascular Molecular and Genetic Laboratory at LDS Hospital, one of the study's authors.

Measuring the levels could also be used to find those people who might go on to have a heart attack, perhaps through regular screening, triggering even closer monitoring or preventive treatment.

"About half of all heart attacks occur in patients with no previous signs of heart disease. The heart attack is a surprise, and very often it's deadly," says Dr. Jeffrey L. Anderson, chief of cardiovascular research at the Intermountain Medical Center Heart Institute and one of the study's authors. "This project has a lot of promise in helping us develop a way to identify these patients who don't show any obvious signs but are at imminent risk of suffering a heart attack."

- read the press release