Thump of an Embryo's Heart Kicks a Stem-Cell Factory Into Gear

By Eliza Strickland | May 14, 2009 10:54 am

blood cell colonyThe beating of the heart inside an embryo doesn’t just circulate blood through the developing creature, it also triggers the formation of blood stem cells, the cells that give rise to all other forms of blood cells, according to two new studies. The surprising findings show that the physical force of the heartbeat and blood flowing through the aorta cause embryonic stem cells to differentiate–although researchers don’t yet understand quite how this is accomplished.

The findings could eventually have practical applications for people with blood cancers and other diseases that are treated with transplants of bone marrow, the site of blood stem cell production. Scientists can make red and white blood cells easily in the laboratory, but bone marrow patients need blood stem cells to constantly replenish their blood supply. Producing these cells, also called hematopoietic stem cells, is much more difficult…. Only about a third of patients who require bone marrow transplants have matching donors. “Basically we cannot offer optimal therapy to two-thirds of patients” [Science News], says Leonard Zon, coauthor of one of the new studies. If researchers can learn how the body stimulates blood stem cell production, they may be able to duplicate the process in the lab, says Zon.

The two studies, published in Nature and Cell, examined the phenomenon in mice and zebrafish, respectively. In the mouse study, the research team placed mouse embryonic stem cells in a centrifuge-like device that mimics sheer stress — the frictional force blood creates when it flows over cells — in a mouse’s aorta. In early embryos, blood stem cells first form on the floor of the aorta. Later in development, they migrate to the bone marrow. Embryonic stem cells exposed to the same magnitude of sheer stress as found in the mouse aorta produced hematopoietic stem cells [Science News]. Different magnitudes of stess, like the amount of force found in a human aorta, showed no such result. Zon’s team found similar results in the zebrafish study, and also showed that a mutant type of embryo that never develops a heart beat, known as a “silent heart” embryo, had fewer blood stem cells.

Both studies also found that levels of nitric oxide, which is known to play a key role in blood vessel formation, increase when blood is flowing…. Researchers think nitric oxide may work as a type of signal to start the process of blood stem cell production [Reuters].

Related Content:
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DISCOVER: The Mother of All Blood Cells
DISCOVER: Researchers Produce Human Blood From Stem Cells

Image: Luigi Adamo and Guillermo Garcia-Cardena. A blood cell colony emerges in response to blood flow.

CATEGORIZED UNDER: Health & Medicine
  • Brian M

    Interesting. How does this square with all you conservative-bashing pro-abortionists out there? Still think it’s nothing but a lump of protoplasm?

  • Jumblepudding

    This ties back into the story about the antioxidants being dangerous. Oxidative stress, like that caused by the presence nitric oxide, is actually necessary for a fetus to develop. Does that mean pregnant women should be careful with the pre-natal vitamins?

  • Frootbat

    When we can feed and house our ridiculously superfluous population and eradicate rape I’ll convert to pro-life. There’s nothing divine about humanity(see population control of all other animals that we purposfully exempt ourselves from) and if creating cures for terminal illnesses requires the use of a nascent life willingly donated by its creator then I’m all for it.

    Women should retain their fundamental right to choose what happens to and in their bodies regardless of what some narrow perspectived relgious fanatic opines.

    On topic, this is fascinating! I ,honestly, will never understand why this kind of research doesn’t get the funding it deserves(despite the obvious “its a baby” crowd whose lives it saves too).

  • Brian M

    Frootbat, so you oppose abortion except in cases of rape? Then we are in agreement along with the vast majority of other conservatives. Welcome to the fold. You’re drifting into the stemcell debate from the abortion debate but, fair enough. The only viable treatment I’ve heard of so far, correct me if I’m wrong, was derived from adult stem cells. And yet everyone persists in villianizing anyone who opposes embryonic research. As far as women having the right to do what they wish with their bodies. Absolutely true. The problem is — it’s not their body being aborted.

  • Eliza Strickland

    Hey, people — let’s not lose sight of the fact that this research was done on ZEBRAFISH and MICE embryos. Nobody is proposing cutting off funding to embryonic stem cell research in lab animals.

  • Ron

    I’m pro choice. Let me clarify this: I think the woman had the right to choice when she chose to get in bed with a fellow. She initiated a process called life. Once started, that sacred process of creating a human, living creature, special above all other creatures we know of; that process cannot be stopped without significant moral consequences, and deficiency.

    The choice, then is for the woman to guard her virtue by employing the power of procreation within the bonds of marriage, when she and a committed partner will be able to care for the new life created, or to forget virtue, and bring life into an environment which is inhospitable or unhealthy for a child’s development. After all, life is sacred, and it’s not our choice to kill at will. The woman made her choice with her body, and that which ensues is NOT the choice, but rather the consequence for her actions.

    Why is this so difficult to grasp? You can borrow money from a loan shark (getting in bed), but you can’t off him just because your deal goes south (abortion). Why is this any different than the life in a womb? Now, if that loan shark attacks a stranger on the west side of town at night unprovoked, then that stranger has every right to immediately and terminally dispatch that stain on civilization without second thought. Similarly, aborting a fetus which was conceived in a rape situation, and even when the life of the mother is at risk is a perfectly sound course of action. But just because you get knocked up after a few too many doesn’t mean you should have the “right” to kill another. That’s not a choice we as humans have agreed to within our credo of behavior.

  • Ron

    Eliza, not to sound brash, but let’s not lose sight of the fact that when we test hairspray on mice, it’s not so we can help the species improve their appearances for job interviews. There’s a reason we test these types of things on mice. One reason: they’re strangely similar in genetic makeup to humans.

    There’s only one end to which successful animal testing can lead: human implementation.

  • Brian M


  • Anthony

    Okay, this is an article about stem cell research, not an abortion chatline. I rarely read comments left on articles that involve stem cell research for this very reason. This is a scientific magazine, this is no place for pro-life debate! Is there some way we can keep these clowns out of the article responses?

  • Ron

    Anthony – you left out the key word: embryonic. Stem cell research and embryonic stem cell research are two entirely different things. If science can’t respect our society’s standards for life, then by all means we have a right and responsibility to stand up and make ourselves heard.

    Where does one draw the line? If we can create human organs should we? If we can only do that by aborting fetuses, is that acceptable? Is it morally correct to create a living breathing human life? What of the side effects that will no doubt be present in the first trials? Is it ok to deliberately inflict that suffering and torment on a life for the advancement of science? Is it ok to clone a child that has been accidentally killed? How about to fight our wars? Do we have the right to bring a child into the world without parents?

    These are moral issues, not scientific challenges. We’ve seen where science without regard to morals or values has led in the past. I think it is prudent to make a stand in an effort to avoid going there. Remember, society is shared by you and me, not either exclusively. We must both work together to respect each other while advancing our capabilities as humans. However, we must also be sure to do this within the bounds of acceptable behavior and correct principles. Principles must govern our actions.

    And yes, if by “clowns”, you mean the majority of Americans, then by all means, censor us. Where do your priorities ie sanctity of life and free speech stand? After all, this is a PUBLIC forum.


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