The stress of public speaking is enough to drive damage-repairing progenitor cells out of the bone marrow into the blood, a study of patients with heart disease has found.
Endothelial progenitor cells (EPCs) are found in the bone marrow, and thought to repair damaged blood vessels once mobilized into the blood by injury or stress. Previous research has shown that strenuous exercise can lead to a dramatic increase in blood EPC levels, but the effects of psychological stress on EPCs had not been examined before.
The new findings were presented Saturday, March 9 at the American College of Cardiology conference in San Francisco. The presenter was cardiovascular research fellow Ronnie Ramadan, MD. Senior authors are Arshed Quyyumi, MD, professor of medicine and director of the Emory Cardiovascular Research Institute, and Viola Vaccarino, MD, PhD, professor and chair of the Department of Epidemiology, Rollins School of Public Health.
In some patients with coronary artery disease, mental stress may precipitate ischemia– a deficiency in blood flow to the heart â€“ a risk factor for adverse events and death independent of other cardiovascular risk factors such as smoking, cholesterol and diabetes.
The Emory researchers are examining mental stress-induced ischemia (MSI) more closely, to understand whether it predicts future cardiac events independent of established risk factors. They looked at 141 patients with documented coronary artery disease, and asked them to perform a http://www.magliettedacalcioit.com standardized public speaking task. 16 percent of this group developed MSI, judged by cardiac imaging with SPECT (single photon emission computed tomography).
The researchers discovered that patients who develop MSI have significantly higher levels of a specialized population of progenitor cells in their blood that have the ability to home to areas of ischemia, but they donâ€™t increase in response to the public speaking task.
In contrast, patients without MSI have their levels of endothelial progenitor cells increase by an average of 21 percent in response to the speaking test.
â€œIt could be that patients with MSI are already at a ceiling, that they’re fully mobilized already,â€ Quyyumi says. â€œOr it could be that there is an impairment in the mobilization.â€
Both groups had their systolic blood pressure increase by about 40 mm Hg in response to speaking test — so theyâ€™re both feeling physiological effects from the mental stress. The MSI group did have more hypertension (baseline blood pressure was 10 mm Hg higher) and a higher prevalence of diabetes.
Ramadan was specifically monitoring rare progenitor cells [1 in 100,000] that have a receptor on their surfaces that allow them to home to areas of injury. The significance of the number and mobilization of these cells and whether they function properly in this setting needs further investigation, he says.