A more accurate method for measuring blood levels of specialized cells that circulate in the bloodstream and repair damage to the arterial lining has been discovered by Duke University Medical Center cardiologists. These cells, known as endothelial progenitor cells (EPC), are produced in the bone marrow and travel to the site of arterial damage.
The researchers said that tests for EPCs could be used to assess a patient's degree of coronary artery disease or risks for suffering a heart attack, and they could become as routine as the cholesterol and lipid tests cardiologists now commonly use. Patients with lower levels of circulating EPCs would be less able to repair cardiac damage. Thus, they would be those with greater disease and at greater risk for a cardiac event, said the Duke cardiologists
Additionally, the researchers found that the EPC levels correlated with the degree of coronary artery disease. Patients with no coronary artery disease had about 70 percent more EPCs than those who had disease in several coronary vessels.
Recent Duke research has linked the progression of the artery-clogging disease atherosclerosis to the inability of EPCs to continuously repair damage to the arterial lining. Duke researchers have shown that -- while risk factors such as poor diet, smoking, high cholesterol levels and inactivity are important in the development of atherosclerosis --the disease progresses as the body's loses its intrinsic ability to repair and rejuvenate itself.
Current methods for measuring EPCs - which can represent as few as one out of 10,000 cells in a given blood sample - are subjective and time-consuming, the researchers said. As an indicator of EPC cell levels, the new method uses measurements of the amount of a detoxification enzyme, known as aldehyde dehydrogenase (ALDH), which is produced in high amounts by EPCs.
"Our studies have shown that using ALDH activity to determine the numbers of EPCs in a blood sample might be a better method for identifying and measuring EPC levels in patients with heart disease than currently used methods," said Duke cardiologist Thomas Povsic, M.D. Povsic presented the results of the Duke research March 12, 2006, during the 55th annual scientific sessions of the American College of Cardiology in Atlanta.
"In order for the use of EPC to become practical in human patients, we need an assay that is quick, reliable and accurate," said Povsic. "Since there are so few EPCs circulating, we literally need a method that can find a needle in a haystack. Our tests so far measuring using ALDH activity to measure EPCs represents a novel approach to solving this problem.