Intermediary Stem Cells in Amniotic Fluid

As research into stem cells broadens, it seems like we're finding them in more and more places. Most recently, stem cells have been isolated from amniotic fluid. Interestingly, they possess qualities which pose as a kind of intermediary between adult and embryonic stem cells. As much as I hate evaluating science on abstracts alone, that's all i've got at the moment until UM updates its databases.

The paper, "Isolation of amniotic stem cell lines with potential for therapy" was published in Nature Biotechnology by groups at Wake Forest and Harvard (Anthony Atala seems to be the senior researcher.) From the looks of things, the amniotic stem cells (ASC) expressed markers that are characteristic of both embryonic and adult stem cells, placing them somewhere on a continium between the two.

"It has been known for decades that both the placenta and amniotic fluid contain multiple progenitor cell types from the developing embryo, including fat, bone, and muscle," said Atala. "We asked the question, 'Is there a possibility that within this cell population we can capture true stem cells?' The answer is yes."

Atala and colleagues discovered a small number of stem cells in amniotic fluid - estimated at one percent - that can give rise to many of the specialized cell types found in the human body.

They report that the ASCs grew well in culture, did not result in tumors, and described their lineage capabilities as multipotent. In layman's terms, that means that the ASCs' daughter cells resulted in more than one cell type but not all cell types (that would be totipotent, like embryonic stem cells.) Perhaps most promising:

Atala said a bank with 100,000 specimens theoretically could supply 99 percent of the U.S. population with perfect genetic matches for transplantation.

However, the authors note that these stem cells are not are therapeutically useful or flexible as embryonic stem cells.

The cells from amniotic fluid "can clearly generate a broad range of important cell types, but they may not do as many tricks as embryonic stem cells," said Dr. Robert Lanza, chief scientist at the stem cell company Advanced Cell Technology. "Either way, I think this work represents a giant step forward for stem cell research."

"While they are fascinating subjects of study in their own right, they are not a substitute for human embryonic stem cells, which allow scientists to address a host of other interesting questions in early human development," said Daley, who began work last year to clone human embryos to produce stem cells.

Now, to organize a amniotic fluid bank like the umbilical cord blood bank............

When I get access to the article, more on this. (Hat tip Bob Abu).

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The article is in Nature Biotech AOP.

I'm not impressed. Having seen half a dozen "adult" stem cell lines come and go, they always are greeted with a big fanfare, then as more rigorous testing is done they don't perform nearly as well as ES cells.

Also, the researchers failed to do the critical chimerism experiment to show totipotency, despite harvesting the cells from mice and rats meaning they could have done it pretty easily. Makes me think they really aren't what they're cracked up to be.

That combined with the timing and I think this is kind of in poor taste. We're going to be debating ES cell research in about 1 week and this will be another distraction from the fact that no one has found a cell type equivalent to ES cells for totipotency, and a lot of adult stem cell lines have been shown to have very low rates of transdifferentiation in vivo despite similar results for transdifferentiation in vitro.

Poor taste? How can reporting on science be in poor taste? I wasn't suggesting that they come close to the therapeutic power of ES cells, in fact I point out places where the authors themselves speak to that fact.

I'll try to explain why I think so.

1. The results are not exceedingly novel, check out the literature on Atala, a lot of this stuff is a bit repetitive.
2. The coverage on multiple sites like BBC, CNN, and some of the less thorough news sources is far less careful about this distinction, and the so-called science advisor on CNN basically made it sound like ES cells are irrelevant.
3. Given the absence of real novelty (and the fact they ignored even neater stuff on parthenogenic ES cells last week), as well as the timing right before the debate begins on ES cell funding in congress, I conclude this is just stem cell hype.

For the life of me I can't figure out why this paper deserves to be on the cover of every single major newspaper, why every news service is covering it etc. These cells aren't more exceptional than cord blood cells (in fact the authors say the cells are located in the placenta too suggesting a possible common source), the findings aren't incredibly novel, they didn't do the most important totipotency experiment, and while the researchers might be saying they don't match embryonic stem cells for totipotency, those sentences are always at the end of the article after a bunch of stuff about how they do everything.

I think it's just bad taste in science reporting. This is good research, no doubt, but the sheer excess of coverage over what I think is something of an incremental finding is a sign of politicization of the science coverage that only serves to give another BS talking point to the anti-ES cell crowd.

This is good research, no doubt, but the sheer excess of coverage over what I think is something of an incremental finding is a sign of politicization of the science coverage that only serves to give another BS talking point to the anti-ES cell crowd.

Well, I must admit I didn't think of it along the lines of timing/poltical but rather as another piece in a larger question about stem cells. I thought it was interesting that these had shown dual properties of ES cells and adult stem cells, closer to being able to establish some kind of continuim as to what is the nature of these cells' potential and what molecular processes dictate that. Perhaps mainstream news outlets are squashing it into 'oh look we can use these instead of dead babies,' but that isn't anything novel either.

I understand not being thrilled w/ the media's treatment of a subject--hell, they botch almost everything about deafness-related research too. But get mad at CNN or Reuters, not at the researchers. It may not revolutionize the field, but hey, Nature isn't what it used to be either. :P