Mouse stem cells heal sheep hearts

[aric]

NATURE

Published online: 16 September 2005

Mouse stem cells heal sheep hearts
Future therapy for heart attacks gets a boost.

Roxanne Khamsi

Embryonic stem cells from mice can help mend the broken hearts of sheep. This cross-species experiment is one more step in finding out whether human embryonic stem cells can mend the damage done by heart attacks.

A heart attack damages the muscle and blood vessels that allow a heart to pump blood around the body. Doctors have long sought a way to repair this damage, and some experts say that embryonic stem cells hold the answer. These cells have the potential to turn into any type of cell needed, such as heart-muscle cells.

Studies have already shown that embryonic stem cells can improve blood flow after an attack in small animals, such as rodents1. But in people, ethical controversies have slowed research into the benefits of embryonic stem cells for ailing hearts.

In human trials scientists have used stem cells from a patient's bone marrow to help the healing. These cells are not as flexible as embryonic ones, but can sometimes be persuaded to turn into the desired cell types. Patients treated this way are able to pump more blood after a heart attack than those who don't get the treatment. But researchers hope that embryonic stem cells might have a greater effect.

Sheep well

Michel Pucéat of the French National Centre for Scientific Research in Montpellier and his colleagues decided to test embryonic stem cells in sheep to see how well they work in large mammals. Because there is not much call for sheep embryonic stem cells, they are hard to source, so the team used mouse cells instead.

The researchers injected about 30 million cells into the hearts of nine sheep that had suffered heart attacks. They found that the sheep pumped blood through their hearts 15% more efficiently than the untreated sheep a month after the injections. Distinctive markers from the stem cells were found inside the sheep hearts, proving that the stem cells had gone to work and replaced some of the damaged tissue. The team reports its results in the Lancet2.

"I think it's very exciting," says Joshua Hare, an expert in cardiac transplantation at the Johns Hopkins University School of Medicine in Baltimore, Maryland.

For the moment, the improvement is of the same order of magnitude as that achieved in humans with bone marrow transplants. But Hare says that the healing should increase over time: other studies have shown the biggest benefit from stem cells two months after injections.

Pucéat says that this form of cardiac therapy holds much future promise. He and his colleagues are currently conducting tests to assess the healing power of human embryonic stem cells in baboons.

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Well, looks like another potential application for stem cells. And yet the research is being deliberately retarded due to some a priori and unsupported notion that embryos are humans beings. It's one thing to claim you're a part of a "Culture of Life" when you protect embryos. But what about when you let people we know to be human beings die early deaths, or live less healthy lives. Where's the Culture of Life there? Do these people deserve what they get?

I bet the people who claim to be a part of the culture of life also think people should pay exorbitant drug prices just so that investors can make more profits. Or that because you can't afford health care, you aren't entitled to serious long-term medical treatment for serious life-threatening ailments.

Culture of Life. Sheesh. What a euphamism.

- Aric

[Vorchia]

I think I´ve had the whole status of the embryo debate with Az once...
I don´t know if I should reply...
Well you know me, you know what college education I´m doing, you know I´m into medical science... I think you know my thoughts on this are scientific and clashing with the opinions of certain creationists out there. However I´m afraid of standing up for my opnions, in RL as much as here for fear of what damage it may do. It seems my closest friends are of radically different opinion on such things as thhis.

But no, embryonic cells, are not sentienent human beings. Cells are alive, yes, that doesn´t make them human, sentienent, capable of thought, emotion, feeling pain. Yes they can be used medically. Should be used medically whenever possible. Its a lot less cruel, mean and unethic then any of modern society´s uses of animals in the bio industry!
How hypocritical is it to go nuts over the use of a bunch of non sentienent CELLS capable of saving lives being used to do so while calmly eating those hamburgers and wearing leather boots and fur coats... Its funny if you think of it.
I never heard of your ´culture of life´ thing but I do know enough activist groups around here aginst just about EVERY sort of scientific research.
And yes its painful to see the exorbitant prices of medical care in certain filthy rich nations. Unfortunately my own country is slowly going the same way. They´re introducing the marketing principle into our healthcare system. Thankfully I am a young and very healthy girl.

[Stouthorn]

Um...if mouse cells cure sheep hearts...and mice and sheep are very, very distantly related...why are we still having the human stem cell debate?

Anyone else following my line of reasoning, here?

[Vorchia]

I hear you but I have no answer. This stem cell use in radically different animals is quite new. I don't even understand how its POSSIBLE to begin with. It goes against all my biological logic and my biology teacher simply didn't believe me when I told him about this publication.
Really, for all medical science I have ever been taught, this shouldn't work. LOL I mean, okay maybe an undifferentiated stemcell doesn't have its MHC's (majorhistocompatibilitycomplex) yet which makes sure it doesn't get killed because of the direct recognition of the alien MHC on these cells. Still you'd expect them to be sought out by the immunesystem for the LACK of MHC because cells with NO MHC get killed too. Cells with no MHC would be recognised as bacteria or parasites or cancer cells and be killed vy the immunesystem.
Could it be possible for these stemcells to somehow aquire host MHC??? I mean even if you assume the alien stemcell itself can get around the immunesystem (unlikely) you'd expect it, upon differentiation, to start to exhibit the MHC its DNA describes, which does differ from the MHC of the host and would lead to a huge immunereaction like that opf any transplantion of tissue with incompatible MHC.
Its majorly unnatural...
Receptorgenes like those of the Tcell receptor and the B cellreceptor can and will reorganise themselves, but NOT MHC genes, right? Right?

Lets wait and see if these results can be reproduced.

[utoraptor3000]

thanks vorchea. always reading about interesting stuff

[Stouthorn]

Well...we share the vast majority of our genetic code with most lifeforms on Earth...wouldn't a stem cell be too early in its development to be recognizably mouse or sheep or human?

[aric]

stouthorn said:

Um...if mouse cells cure sheep hearts...and mice and sheep are very, very distantly related...why are we still having the human stem cell debate?

Anyone else following my line of reasoning, here?

"For the moment, the improvement is of the same order of magnitude as that achieved in humans with bone marrow transplants."

I'm guessing that human embryo stem cells will work better for human patients than non-human stem cells.

- Aric

[Stouthorn]

True, but seeing as it's quite likely that the whole human stem cell issue will be stagnating as the abortion war goes on, maybe more research should be done in the area of inter-species stem cell work.