Sunday, January 07, 2007

AFS Cells: A Non-controversial source of pluripotent cells?

There is a new report out today that suggests there is a new, non-controversial and "ethically sound" source of pluripotent stem cells: amniotic-fluid stem cells, which, as the name indicates, are stem cells found free-floating in the amniotic fluid. They are also apparently present in the placenta.

According to Dr. Anthony Atala, the specialist at Wake Forest University who led the research team, these cells are neither embryonic stem cells nor are they adult stem cells. They're something in between, fully flexible like embryonic stem cells, but non-controversial. And this is where I take issue. Dr. Atala is saying, and I quote from the above article,
the amniotic cells can be taken easily and harmlessly from the placenta or from pregnant women by amniocentesis
while David Prentice, a senior fellow in life sciences at the Family Research Council, (who strongly oppose embryonic stem cells) says that the AFS cells come with "little ethical baggage". But anyone who's been through amniocentesis knows that there is actually a risk of miscarriage with every insertion of a needle into the womb; according to the CDC, it's a risk of one in 200 to one in 400 women will miscarry, depending on the skill of the person performing the procedure.

This is not harmless. This is not easy. This is not little ethical baggage. If it's so bad, so wrong, to create embyronic stem cells because of the loss of potential life, how can anyone justify the potential miscarriage of a developing, in utero fetus?

8 comments:

Kathryn Hinsch said...

Some insightful commentary on the issue from Sam Berger and Jonathan Moreno at the Center for American Progress:

Scientists announced yesterday that they had found stem cells in the amniotic fluid of pregnant women that have similar characteristics to embryonic stem cells. While these new stem cells hold great promise, they will not replace embryonic stem cells:

There are questions over whether the amniotic-fluid stem cells can differentiate into as many types of cells as embryonic stem cells, thereby limiting their medical application.

It is unlikely that amniotic-fluid stem cells will be as useful as embryonic stem cells for studying early human development, one of the most promising areas of stem cell research.

Scientists already know that stem cell research is not “one-size-fits-all”; different types of stem cells will be necessary to treat different types of injuries and diseases, so while these new stem cells will be medically useful, they will likely not replace embryonic stem cell research and therapies.

It will take years for other scientists to reproduce these results, then try to convert them to materials that could be used first in animal models of human disease, and then test them in a few people for safety. Meanwhile, we already know how to obtain embryonic stem cells, while the research continues to advance rapidly,

Prominent stem cell scientists agree that the amniotic-fluid stem cells will not replace embryonic stem cells:
o Dr. Robert Lanza, chief scientist at the stem cell company Advanced Cell Technology, said “[these new stem cells] can clearly generate a broad range of important cell types, but they may not do as many tricks as embryonic stem cells.”

o Dr. George Daley, a Harvard University stem cell researcher, said “While the [new stem cells] 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.”

o Dr. Larry Goldstein, a professor of cellular and molecular medicine at UC San Diego, said the absence of tumors in the new stem cells might signal a limitation. "It makes me wonder how pluripotent they are." Though the cells might prove useful in some circumstances, Goldstein said, they aren't a substitute for embryonic stem cells. “They built a screwdriver here, but I need a wrench.”

o Dr. Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine and the leader of the group of scientists that discovered the amniotic-fluid stem cells, commented that the new stem cells would not replace embryonic stem cells

Researchers have used embryonic stem cells in laboratory animals to treat paralysis, slow vision loss, and reverse some of the symptoms of Parkinson’s disease. They have also used human embryonic stem cells to create cardiovascular precursor cells that could lead to treatments for heart diseases, T-cells that could lead to a cure for AIDS, and insulin-secreting cells that could lead to a cure for diabetes.
While these new stem cells will not replace embryonic stem cells, the discovery does demonstrate the potential in basic research on stem cells from various sources, and the need to pursue stem cell research on all fronts and from all sources. Congress needs to give our scientists access to the best tools available in the race for life-saving cures, and it can take the first step this week by passing the Stem Cell Research Enhancement Act of 2007.

Emilie Clemmens said...

Thank you, BV, for pointing out what was an obvious ethical issue for me as soon as I heard this news. I am frustrated and shocked that I have not yet seen any reference to the risk of miscarriage with amniocentesis in any of the stories published on major news outlets. Perhaps this is a good opportunity for us to speak up about this--not only the risks associated with amnio and the ethical dilemmas therein, but also the fact that it hasn't even been mentioned by the quoted representatives of industry and academia.

Rebecca said...

What about just collecting the amniotic fluid during delivery? I have not read that the stem cells need to be collected during an amniocentisis at a certain week of gtestation. Also, I think the idea is that if these cells are taken from an amnio, it would be from a procedure that was already performed or going to be performed anyway.

Also, an embryo isn't potential life, it is life. It is a distinct complete human organism. Whether you think that life deserves protection is another issue.

Emilie Clemmens said...

"Also, I think the idea is that if these cells are taken from an amnio, it would be from a procedure that was already performed or going to be performed anyway."

Yes, I had anticipated that this would be the case, but the potential for coercion, be it monetary or community pressures, is still an issue. All of which, I realize, have been addressed at one time or another in a different context, for example, with the fetal tissue debate, but I believe there may be unique potential for coercion here, given the "routine-ness" of the procedure.

Behind all this is a separate issue that has been on my mind personally and professionally, which is the purpose and place of the amnio procedure to begin with. It is used to test for conditions that currently cannot be treated, carries a substantial risk for the fetus, and yet is still fairly commonly performed. My concern, of course, is with adequate counseling for patients making this decision; I myself have felt pressured to have unnecessary blood tests during pregnancy. (That said, diagnostic tests are improving and amnio and CVS may be a thing of the past in coming years.)

Then back to the topic at hand, will women be led to think, "Oh, it's not a big risk for me or my baby, and it will help others..."?

Collection of the stem cells with delivery, of course, avoids this ethical issue and in fact is a wonderful opportunity for science and medicine.

Alexandra said...

In regards to the risk of miscarriage after an amniocentesis, there was an article in the journal of Obstetrics & Gynecology back in November 2006 stating that a new study did not find an increased risk of miscarriage for women who had amnio and those who did not.

Abstract here:

http://www.greenjournal.org/cgi/content/abstract/108/5/1067?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&andorexacttitle=and&titleabstract=amniocentesis&andorexacttitleabs=and&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT

MSNBC Article here:

http://www.msnbc.msn.com/id/15755732/

I've read elsewhere that the numbers the CDC cites are the result of studies done in the 1970's and that the 0.5% is considered by many to be an overestimate.

While there is always going to be some risk when it comes to poking needles into a woman who is pregnant, it seems to me that if there is going to be a discussion on obtaining stem cells through amniocentesis then the information provided to women about the risks should be current - not based on 30 year old data that was obtained with 30 year old technology.

Emilie Clemmens said...

Thank you for that important clarification, Alexandra. And I think you hit the nail on the head for me when you said "if there's going to be a discussion on obtaining stem cells through amniocentesis..." This is really my point: that there should be a discussion and it should at least recognize potential risk to a fetus, instead of disregarding it entirely as Dr. Atala did with the use of the term "harmlessly".

Sue Trinidad said...

Right--the new report recommending prenatal screening for Down syndrome (etc) for *all* women is based on the new finding that amnio doesn't increase the risk of miscarriage.

The risk of miscarriage was the reason that amnio was recommended only for women 35+, based on the idea that the likelihood of identifying a fetal abnormality was enough higher in this age group to justify the risk of complications from the amnio.

I'll check to see whether we already have a separate blog entry on this--if not, will draft one, as it's an important change in practice.

BuddhistValkyrie said...

I admit I just did a quick search to refresh my memory on what the risk of amniocentesis is, and the data could be much different now. But like Emilie, my main horror is at the fact that it's being tossed off without thought, or discussion!

Plus, consider what Prof. Bonnie Steinbock recently mentioned in a couple of less-national news articles: amniocentesis itself is a very controversial procedure, because around 90% of the women who discover there are problems (potential or guaranteed) opt to abort.

There are a slew of ethical issues here that should be part of the public debate about this, and simply are not. I agree, again, with Emilie and think this is a great opportunity for us to drive the debate. I call shotgun! ;)