HELPING THE HEART REGENERATE ITSELF

by Bennett Daviss
Scientists have known for a decade that if a mouse’s heart is damaged during the first seven days after its born, the heart will regenerate new tissue to replace the damaged portion.
Now researchers at the University of Texas Southwestern Medical Center think they’ve found a way to help people regenerate heart tissue, no matter their age.
The team discovered that a trio of proteins work together to shut off the heart’s ability to regenerate itself. By turning down or off the genetic switches that produce one or more of those proteins, the heart might be able to repair itself.
The first protein is called Meis1, which prevents heart cells from dividing to make new ones. When the scientists deleted the gene that makes Meis1 from a mouse’s genome, the mouse’s heart could make new cells beyond the first week of life. But it couldn’t do so for long.
The second is Hoxb13, which carries Meis1 into a cell’s nucleus.
The researchers erased the genes that make Meis1 and Hoxb13 from the genomes of mice, then induced heart attacks in those mice. The hearts of the affected mice returned quickly to a state similar to hearts of mice that aren’t yet adults, a time when organs are still developing into a healthy, mature state.
The final protein is calcineurin, which regulates both Meis1 and Hoxb13. By canceling a mouse’s ability to make this protein, the scientists extended even more the length of time that hearts could repair themselves.
TRENDPOST: Because calcineurin is involved in diseases such as diabetes and rheumatoid arthritis, there already are drugs on the market that use it as an ingredient. These drugs may soon be tested for their ability to also help heal hearts damaged by heart attacks, hypertension, and other cardiac ailments.