Another Step Closer to Repairing Damaged Heart Tissue

Dr. Kelly R. Stevens, Dr. Charles "Chuck" Murry and fellow researchers of the University of Washington have successfully overcome several glitches standing in the way of the development of human tissue patches that can repair damaged hearts.

These patches range from less than a millimeter to a half-inch in diameter. Previously fabricated heart tissues failed during transplantation because nutrients and oxygen could not reach the center of the patch. In addition, the scaffolding materials that were used to position the cells proved to be harmful at times.

Since previous attempts had failed because the patches composed of only heart muscle cells would not survive long enough after transplantation, the researchers observed the possibility of adding supply lines for oxygen and nutrients.

The researchers added cells similar to those that line our blood vessels and cells that provide muscular support for blood vessels. These cells were derived from embryonic stem cells or cells from more mature sources like the umbilical cord.

Researchers believe that the tissue’s ability to form blood vessels made the difference in the survival of the patches. Blood could flow to the patch in the rat’s circulatory system because of the pre-formed vessels within the patch. Also, the supporting cells helped to strengthen the patch to more closely resemble human heart muscle. Furthermore, the patches grew to be 10 times larger than patches from other research trials.

“Equally as exciting, the scientists observed that the patches of engineered tissue actively contracted. Moreover, these contractions could be electronically paced, up to what would translate to 120 beats per minute. Beyond that point, the tissue patch didn't relax fully and the contractions weakened. However, the average resting adult heart pulses about 70 beats per minute. This suggests that the engineered tissue could, within limits, theoretically keep pace with typical adult heart muscle, according to the study authors.”

The results show much promise for treating tissue damage due to heart attack. In addition, the study sheds new light on designing and transplanting tissue for other
types of regenerative therapies unrelated to heart disease.

A major obstacle remains the likelihood that our immune systems will accept and not reject the transplant without having to take medications for the rest of our lives. Murry hopes that further research will uncover ways to create tissues from a person’s own cells so that the body will recognize the patches as ‘self’ tissue.

Researchers seem to be on the right track, however much more testing is needed to determine whether the implants actually improve physical functioning. Hopefully this new treatment could be put into practice some day soon and significantly improve the lives of those who have suffered heart attacks, thereby altering the currently staggering prognosis for many.

Major Improvements Made In Engineering Heart Repair Patches From Stem Cells

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