Sick cells could signal heart risk: sensitive method spots abnormalities that foretell attacks.
Certain cells in blood might help identify patients who remain at risk of a heart attack despite passing diagnostic tests when experiencing chest pain.
In the opening throes of a heart attack, endothelial cells from the inner lining of blood vessels get set adrift in the bloodstream, scientists report in the March 21 Science Translational Medicine. Heart attack patients have more of these endothelial cells in their blood than healthy people, and the cells take abnormal shapes, says Eric Topol, a cardiologist at Scripps Research Institute in La Jolla, Calif. "These are sick cells that have been subjected to profound inflammation."
Topol and colleagues found the abnormal cells using a new cell-sorting technology that can detect a single endothelial cell among millions of blood cells. Researchers sampled blood from 50 people with a median age of 58.5 who had chest pains that turned out to be heart attacks, and also tested 44 younger healthy volunteers and 10 healthy people age-matched to the heart attack patients.
The tests found four times as many circulating endothelial cells in the heart attack group as in the healthy volunteers. The unusual cells also clustered together and often contained multiple nuclei.
"This is a fascinating insight," says cardiologist Christopher Boos at Poole Hospital in Dorset, England. "But this is very much in the exploratory phase," as researchers have yet to prove that the abnormal cells come from the coronary arteries. Heart attacks occur when plaque in a coronary artery tears loose, inducing clotting that blocks the artery and disrupts blood flow to the heart.
But sometimes, Topol says, a person gets chest pain with no other evidence of a heart attack. The patient's heart rhythm is good, blood flow is adequate and blood analysis shows no telltale signs of dying heart cells. In these people, the body has often dissolved a clot before any heart damage could occur, Topol says.
He hopes to investigate whether these people have abnormal endothelial cells in circulation. Evidence of that would suggest an unstable coronary plaque--a heart attack still waiting to happen.