Clinical trials are currently underway for stem cell injections to quicken healing of the heart after a heart attack. There are two ways being researched using patches of cardiac cells: the cells staying temporarily in stomach tissue, and using a biodegradable mesh to help the heart rebuild itself.
After a heart attack, the heart muscles is weakened and damaged, so the patch must be able to both cover the damaged area and do the work of the weakened areas. Researchers from Israel wondered if the body could be used to create the patch and so they implanted patches of lab-grown heart cells onto rats’ omentums (a fatty tissue in the stomach that is rich in blood vessels). They left the patches (experimental patches) on the omentums for a week before they transferred them to the rats’ damaged hearts. The patch (initially grown on a mesh scaffold from the heart cells of neonatal rats and other compounds to aid development) was found to have more blood vessels after spending a week on the rats’ omentum compared to the patches that were immediately onto the damaged hearts. The experimental patches were also found to contribute to thicker walls and they integrated into the surrounding heart tissue better than the control patches.
At the University of Arizona, a biodegradable scaffold which gives the heart muscle a 3D frame to grow on (once inside the body) has been developed. This scaffold is important because most injected stem cells don’t survive without a supporting matrix. The new patch is designed to disintegrate after about 3 weeks, leaving only the newly grown tissue. Tests on lab rats have shown that the patch increases the wall thickness and blow flow of the heart and also, when there were enough heart muscle cells, the patch started contractions on its own.
Phase 1 clinical trials are currently being held to test for safety in people.
By Rachel Hur 42183583
(This article can be viewed at the following link: http://www.scientificamerican.com/article.cfm?id=patches-repair-damaged-hearts)
