Jonathan Choy brings previous research experience in the mechanisms of controlled cell death to his work at the Cardiovascular Research Laboratory in the McDonald Research Laboratories at St. Paul's Hospital. His research focuses on atherosclerotic plaques in the vascular system—also known as hardening of the arteries—caused by a buildup of lipids on the innermost portion of the arteries. Advanced plaques tend to break down and rupture, and can lead to blood clots and heart attack. Jonathan is specifically studying the role of granzyme B—a protein normally used by the immune system to kill abnormal and infected cells—in causing plaque rupture. He is investigating whether granzyme B destroys structural cells in the plaques, thereby reducing the integrity of this part of the vessel wall. Understanding the processes that alter the structural integrity of the atherosclerotic plaques could enable control of some of the events that lead to heart attacks.