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IBBME Core Faculty Milica Radisic achieves heart engineering breakthrough

Milica Radisic wins Connaught Fund Innovation Award for preventing cell death in engineered tissue

By Jenny Hall
originally posted to the University of Toronto e-Bulletin
Monday, May 9, 2011

The best medicine for a broken heart, it turns out, might not be time or chocolate or revenge or any of the cures commonly advanced in pop culture, but a peptide with the unlikely name QHREDGS.

The researcher responsible for its discovery, Professor Milica Radisic of chemical engineering and applied chemistry and the Institute for Biomaterials and Biomedical Engineering, has won a Connaught Fund Innovation Award, which will allow her to further test her discovery.

Radisic is a leader in cardiovascular tissue engineering, the science of building living tissues using cells and biomaterials. She grows heart cells in her lab and then engineers them into heart tissues that beat.

But she — and other tissue engineers — consistently run into trouble when they try to build bigger tissues like hearts.

“One of the key problems with tissue engineering,” she said, “is cell death. Cells die, partly because our cultivation systems are not as perfect as our bodies.” In our bodies, tiny blood vessels called capillaries bring oxygen and nutrients to every cell , but blood vessels can’t yet be effectively grown in labs, which leaves synthetic tissues vulnerable.

Enter QHREDGS, a peptide is a small molecule made up of amino acids, which occur naturally in our bodies. Radisic and collaborators discovered that this particular peptide prevented cell death in two types of cells — cardiomyocytes, which are beating heart cells, and endothelial cells, which line our blood vessels.

“If the cell is experiencing adverse conditions, treatment with the peptide will help it survive,” she said. “An ‘adverse condition’ would be analogous to heart disease. In the lab we can mimic this by using drugs that are known to cause cell death — some of them are used in cancer treatments because they cause a special kind of cell death called apoptosis. We also treat the cells with peroxide, which mimics the shock introduced by free radicals.” (Free radicals are molecules that cause tissue damage and aging.)

The peptide also helped protect cells that were deprived of oxygen and nutrients because they were located in the centre of a large aggregation of cells.

One of the main advantages of Radisic’s peptide is that unlike whole proteins, which are often used in similar contexts, it is cheap and easy to work with. She hopes it will become a tool for researchers everywhere.

Her Innovation Award from the Connaught Fund will allow her to test the peptide’s effect on pluripotent stem cells, cells that have the potential to become any other kind of cell.

The Connaught Fund is the U of T’s premier prestigious internal funding mechanism. It makes awards to the researchers whose work has the potential to bring significant benefit to society. The Innovation Award, one of its programs, seeks to accelerate the development of promising technology and promote commercialization and knowledge transfer.

The ultimate goal of all Radisic’s work? To “regenerate hearts.”

The heart, she said, has a very limited ability to regenerate itself. Combined with the fact that heart disease is the leading cause of death in most western societies, the potential impact of her work is enormous.

“Professor Radisic exemplifies the spirit of Connaught,” said Professor Paul Young, vice-president (research). “Her work is creative and on the leading edge of an emerging, exciting field. It has the potential to bring enormous benefit to society.”

Though it sounds like science fiction, she believes that regenerating hearts is not an unrealistic goal. Two-dimensional tissues like skin or tissues like cartilage that don’t have blood vessels in them are already being regenerated. Burn victims, for example, have already received living skin replacements.

“Science,” she said, “continues to amaze me. This is reachable in our lifetime.”