Ask the doctor: How can I keep my coronary arteries from going into painful spasms?
Q. What can be done for endothelial dysfunction that causes coronary artery spasms and requires nitroglycerin at least four times a day?
A. The endothelial cells are the flat cells that line the insides of blood vessels. Until recently, they were thought to sit passively inside blood vessels, like tiles on a floor. We now know that they play major roles in diseases as diverse as atherosclerosis, hypertension, and cancer. Endothelial cells control the tone of the muscles around the arteries in response to oxygen, blood sugar, and other metabolic variables. In this way, they regulate the size of the artery at any given moment, which determines how much blood can flow through it.