Milica Radisic, 32
Patching damaged hearts
University of Toronto
The heart has a limited capacity to generate new cells on its own, making it hard to heal after injury. Scientists have experimented with injecting stem cells into the heart, but they have found it difficult to predict how the cells will behave, and they've had little success in coaxing cells to make functional tissue. To better anticipate which cell types may help heal hearts, bioengineer Milica Radisic has used embryonic stem cells to create a small patch that mimics human heart tissue.
Radisic grew her first heart patches using cells from the hearts of newborn rats. But coaxing the cells to form functioning heart tissue proved challenging; established tissue-engineering techniques didn't work. Radisic hit upon the idea of applying a small electric field to the cardiac cells, similar to the one formed as the heart develops in an embryo. This spurred the cells to connect in patterns that resembled those of actual heart tissue.
Radisic, an assistant professor of chemical engineering, is now using the same technique to grow heart patches derived from human embryonic stem cells. The patches respond to various stimuli as real heart muscle would, providing a way to more accurately test the potential of different cell lines and new drugs. Radisic is now adding various lines of stem cells to the engineered patches to see which--if any--multiply and form functioning heart tissue; her goal is to find cells that are useful in repairing muscle damaged by a heart attack or by high blood pressure. She also aims to help researchers find treatments for heart damage associated with diabetes by designing a patch that simulates the heart tissue of a person with that disease. --Jennifer Chu