Molecule prompts damaged heart cells to repair themselves after a heart attack

Apr 10, 2009
Drs. J. Michael DiMaio and Ildiko Bock-Marquette have found in mice that the molecule Thymosin beta-4 affects developmental gene expression in heart cells as early as 24 hours after systemic injection. The new findings suggest that introducing TB4 after a heart attack encourages new growth and repair of these cells. Credit: UT Southwestern Medical Center

A protein that the heart produces during its early development reactivates the embryonic coronary developmental program and initiates migration of heart cells and blood vessel growth after a heart attack, researchers at UT Southwestern Medical Center have found.

The molecule, Thymosin beta-4 (TB4), is expressed by during the heart's development and encourages migration of heart cells. The new findings in mice suggest that introducing TB4 systemically after a heart attack encourages new growth and repair of heart cells. The research findings indicate that the molecule affects developmental gene expression as early as 24 hours after systemic injection. The UT Southwestern study is online and will appear in an upcoming issue of the Journal of Molecular and Cellular Cardiology.

"This molecule has the potential to reprogram cells in the body to get them to do what you want them to do," said Dr. J. Michael DiMaio, associate professor of cardiothoracic surgery at UT Southwestern and senior author of the study. Obviously, the clinical implications of this are enormous because of the potential to reverse damage inflicted on heart cells after a heart attack."

Tremendous medical progress has been made to counter the damaging effects of heart attacks, but ordinarily, mammalian hearts are incapable of repairing themselves following damage. They are also limited in their ability to form new blood vessels. Earlier studies demonstrated that TB4 is expressed in the embryonic heart and stimulates cardiac vessels to form. It was therefore thought that introduction of TB4 might activate new in the adult heart.

In this mouse study researchers found that TB4 initiates capillary tube formation of adult coronary endothelial cells in tissue culture. The molecule also encourages cardiac regeneration by inhibiting death in after an injury such as a heart attack and by stimulating new vessel growth.

"We observed that by injecting this protein systemically, there was increased cardiac function after a heart attack," said Dr. Ildiko Bock-Marquette, assistant professor of cardiothoracic surgery at UT Southwestern and the study's lead author. "We hope this protein can inhibit cell death that occurs during a heart attack in the short term, and that it may initiate new growth of coronary vessels by activating progenitor cells in the long term."

Researchers assessed the effect of TB4 on new vessel growth in adult mice after inducing heart attacks and then following up by introducing TB4 into the animals. An examination of the capillary smooth muscle cells following treatment with TB4 showed a significant increase in capillary density in the three days afterward near the site of the , the scientists reported.

Further studies will examine whether the same events occur in larger mammals and which receptors are responsible for the action of this molecule.

Source: UT Southwestern Medical Center (news : web)

Explore further: Crystal structure reveals how minor variations make receptor proteins activate or inhibit natural killer cells

add to favorites email to friend print save as pdf

Related Stories

Adult pig stem cells repair heart damage

Nov 14, 2006

U.S. scientists have successfully grown large numbers of stem cells from adult pigs' heart tissue and used the cells to repair heart attack damage.

Heart attacks and nerves

Nov 15, 2007

Scientists have found a naturally occurring protein, known as nerve growth factor, can dramatically improve the survival of heart cells.

Heart derived stem cells develop into heart muscle

Apr 23, 2008

Dutch researchers at University Medical Center Utrecht and the Hubrecht Institute have succeeded in growing large numbers of stem cells from adult human hearts into new heart muscle cells. A breakthrough in stem cell research. ...

Recommended for you

User comments : 0