Grant: Doctoral Research Award: Canada Graduate Scholarships

Valve replacement surgery is one of the most common procedures performed by cardiac surgeons. Most patients undergoing valve replacement surgery receive either a tissue or mechanical valve. Mechanical valves are more durable than tissue valves, but require a daily blood thinner. Tissue valves are made from either cow or pig tissue, do not require blood thinners, but tend to fail over time requiring another operation. One reason these valves fail is due to a slow rejection of the animal tissue by the human immune system. Our ultimate goal is to create an artificial heart valve that does not require blood thinners and will last the lifetime of the patient. To do this, we will use autologous stem cells to repopulate animal tissue heart valves to prevent the immune system from recognizing this foreign tissue. We will achieve this goal with two experiments. First, we will use stem cells taken from human patients bone marrow and grow them on an animal tissue scaffold, analyzing the human immune response to this tissue in-vitro with donor human blood. These results will be used to inform the following experiment. Second, we have developed a rat aortic valve transplant model that closely resembles what happens in human patients. We will use rat stem cells to repopulate guinea pig aortic valves, then implant these valves back into rats to analyze the immune response to this tissue in-vivo. The proposed studies will contribute to our ultimate goal of creating an artificial heart valve that does not require blood thinners, is durable, available and leads to improved long-term patient outcomes.