Genetic markers could help predict stroke in patients with heart disease

Researchers at the Intermountain Medical Center Heart Institute in Salt Lake City have identified a biological process that could help physicians predict when someone with heart disease is likely to have a heart attack in the near future.

A new study by the team has identified plasma levels of two markers - microRNA 122 and 126 - that appear to decline a few days before a person suffers a heart attack.

Results of the study could help the 715,000 Americans who suffer from heart attacks each year.

"It's always been a mystery trying to identify people with heart disease who are at imminent risk of having a heart attack," Oxana Galenko, DBMSC, with the Intermountain Medical Center Heart Institute Cardiovascular Research Laboratory, who is the lead researcher in the study, said.

"Currently, there's no blood test that allows us to say, 'yes, this person will likely have a heart attack in the near future'. But identifying what happens to these markers has given us a place to start," Galenko said.

Researchers presented the results of the study at the 2014 American College of Cardiology Scientific Sessions in Washington, DC recently.

During a heart attack, one of the coronary arteries that feed blood into the heart becomes completely blocked, preventing necessary oxygen and nourishment from reaching the heart muscle. When this happens, the heart muscle dies and never recovers resulting in heart failure or death.

The discovery of the diminishing microRNA markers began with the understanding of a basic process in biology known as the central dogma. DNA contains the genetic information an organism uses to grow and develop. Messenger ribonucleic acid (mRNA) communicates this information to the rest of the body and translates the genetic information into protein. This is known as gene expression.

In 1993 scientists discovered small forms of RNA didn't follow standard translation patterns. These forms, known as microRNA, weren't making proteins, but rather were interfering with mRNA to prevent translation.

At the same time, physicians at the Intermountain Medical Center Heart Institute created the Intermountain Heart Study Registry, which includes blood samples from a massive number of heart patients for research. Today the registry contains more than 30,000 DNA samples.

Galenko and her team looked at samples in the registry from 30 patients who had suffered a heart attack within 44 days of having their blood collected.

Researchers examined factors such as age, gender, race, elevated amounts of or cholesterol in the bloodstream, high blood pressure, and diabetes. They noticed that within two weeks of experiencing a heart attack, patient's microRNA 122 and 126 dramatically dropped.

The result: Galenko believes that something about these microRNAs being present and interrupting the translation process prevents people with heart disease from having a heart attack.