Following genotyping and statistical analyses, the research team discovered that genetic variations involving endothelial dysfunction - a hallmark for vascular diseases, such as atherosclerosis - and platelet aggregation appear to contribute to depressive symptoms.

Specifically, they identified one marker within the vonWillebrand factor (vWF) gene that appears to have a significant association. vWF is a protein produced by the endothelium that is critical to the initial stages of blood clotting by helping platelets stick to damaged blood vessels. When elevated in concentration, VWF is a strong predictor of endothelial dysfunction and a risk factor for atherosclerosis.

"Although further study is needed, our findings suggest that endothelial dysfunction may be a novel mechanism contributing to depressive symptoms among heart disease patients," said McCaffery, who is also an assistant professor of psychiatry and human behavior at The Warren Alpert Medical School of Brown University.

Researchers note that the candidate gene approach used in the study is limited by the current knowledge of the biology of depression in cardiac patients. They call for genome-wide association studies - which involve the study of genetic variations across the entire human genome - to further identify other genes and pathways that may be associated with depression and heart disease.

ifespan