Primary Human Coronary Artery Endothelial Cells (HCAEC) are isolated from the coronary arteries (the right and the left coronary artery, including the anterior descending and the circumflex branches) from single donors. They are crucially involved in the regulation of coronary blood flow and cardiac functions and are consequently useful for in vitro studies of diseases such as thrombosis, atherosclerosis, and hypertension. HCAEC are also suitable for studying functional vasodilators, such as prostacyclin, bradykinin, or nitric oxide.