Stem Cells Repair Hearts Damaged by a Heart Attack

A joint research project with Cornell University, the University of Bonn and the University of Pittsburgh has resulted in the transplant of living embryonic heart cells into the heart tissues in mice who had had a heart attack. The results showed that the mice developed a resistance to cardiac arrhythmias, which is one of the results of a heart attack and one of the main causes of death .

The researchers discovered that a protein, connexin43, which is made by the transplanted embryonic heart cells has the ability to improve the electrical connections to the other cells in the heart. The results showed that the improved connections were able to help activate the transplants that were placed deep down in the part of the heart tissue that had been damaged. They were able to reverse the risk of what is the number one cause of sudden death, ventricular arrhythmias.

There have been transplants done before that were done with a large variety of cells in failing hearts and they were able to achieve some improvement in the function of the heart. But one type of transplant where they used skeletal muscle cells actually had the opposite effect and caused more arrhythmias. In this instance, when they transplanted the embryonic heart cells, the arrhythmias were reversed, and the electrical stability as well as the heart function returned to normal.

Researchers have known that there is great potential in using these cell-based therapies for the purpose of combating a great many serious diseases, but up until now, they have not had the tools available that would allow them to assess the functions of the cells after they were transplanted.

In this study, they were able to discover that the transplanted embryonic cells were actually making the connections with the healthy cells and by using genetically modified heart cells that express themselves with a fluorescent sensor, they were able to verify that the transplanted cells were activated when there were normal heart contractions.