A new study in mice shows such that nature has a way of replacing damaged or destroyed tissues in the body with stem cells. When a pregnant mouse has a heart attack, her fetus donates some of its stem cells to help rebuild the damaged heart tissue.
The researchers started with two lines of mice: normal mice and mice genetically engineered to express green fluorescent protein (GFP), which glows a distinctive green when exposed to blue light, in their cells. They mated normal female mice with GFP-producing male mice. This meant that half the resulting fetuses had the GFP gene, too, making their cells glow, too. Twelve days later—a little less than two-thirds of the way through a normal mouse pregnancy—the researchers gave half the pregnant mice heart attacks. When the scientists examined the female mice’s heart tissue two weeks after the heart attacks, they found lots of glowing green tissue—cells that came from the fetus—in the mom’s heart. Mice who had heart attacks had eight times as many cells from the fetus in their hearts as mice who hadn’t had a heart attack did, meaning the high volume of fetal cells was a response to the heart attack.
Doctors have observed that women who experience weakness of the heart during pregnancy or shortly after giving birth have better recovery rates than any other group of heart failure patients. This study suggests that fetal stem cells may help human mothers, as well as mice, recover from heart damage. It may also explain another curious clinical observation: The hearts of two women who suffered from severe heart weakness were later found to contain cells derived from the cells of a male fetus years after they gave birth to their sons. The same thing seems to hold true for other organs. When pregnant women have damage in other organs, including the brain, lung, and liver, earlier studies have shown, fetal cells show up there, too.
Source: Discover Magazine
Kara RJ, Bolli P, Karakikes I, Matsunaga I, Tripodi J, Tanweer O, Altman P, Shachter NS, Nakano A, Najfeld V, & Chaudhry HW (2011). Fetal Cells Traffic to Injured Maternal Myocardium and Undergo Cardiac Differentiation. Circulation research PMID: 22082491