Researchers have known for some time that women who experience weakened heart function in the months before and after childbirth (a condition known as peripartum cardiomyopathy) recover more quickly than any other group of heart failure patients. Now, a team of researchers from Mt. Sinai School of Medicine thinks it may know why.
The researchers have demonstrated that when a pregnant mouse suffers from a heart attack, her fetus will actually donate cells that can migrate to mom's heart before differentiating into different types of cardiac cells, aiding in the heart's regenerative processes.
80 Beats' Valerie Ross explains how the researchers discovered the helpful fetuses:
- 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.
- What's more, the embryo's stem cells had differentiated into various types of heart tissue, including cardiomyocytes, the rhythmically contracting muscle cells that produce a heartbeat.
According to the researchers, whose findings are published in the latest issue of The American Heart Association's Circulation Research, their findings may help explain not only the rapid recovery of patients with peripartum cardiomyopathy, but also why researchers have previously discovered cells containing Y-chromosomes (i.e. male cells) in the hearts of women who had previously given birth to boys.