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October 17, 2005

Stem cell breakthrough ensures whole embryos will be flushed

Scientists have developed a technique for harvesting stem cells without destroying the embryo. [NYT permalink] The researchers successfully extracted tissue from fertilized mouse ovum and cultured it for stem cells. Allegedly, this is an ethical breakthrough because the egg survived to process.

What the article doesn't mention that the ovum will be discarded anyway. If this technique were used to generate human stem cells, the fertilized egg would have to be thrown away. Nobody would want to gestate an ovum after it had been raided for stem cells.

It's sad to see political theater being played out in the laboratory.

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Merriam-Webster does accept "ovum" as a term for "embryo" in non-technical writing, but you might consider using "embryo" in this context, for those of us who thought that "ovum" implied a single cell.

>Nobody would want to gestate an ovum after it had been raided for stem cells.

Sorry to be dense, but why not? Your baby would be ideally genetically matched with all sorts of therapies that might result.

Ted, you obviously paid too close attention in Cell Bio. I dropped it after a couple weeks.

I forget who the comedian was, but he favored non-stem-cell hospitals for the religious right and the neocons, and stem-cell hospitals for the rest of us. Fine by me. And don't laugh - if Bush gets his way, our stem-cell hospital will be Europe. Well, at least it will be for those who can afford it.

I'll second Michael Schmidt's why not. really, why not? I would be willing to bet (actual money mind you) that a small but significant percentage of couples who are willing to create a bunch of embryos for IVF would be also willing to create stem cell lines from them if they could be guarenteed that the embryos would not be harmed. After all, if you could find merely 50 such couples a year, the gain in the number, diversity and vitality of cell lines would be remarkable.

If you're being really technical, "embryo" isn't quite the right word either. We're probably talking blastocysts here.

It would be unethical to gestate an embryo that had been tampered with in that way.

We don't know how the harvesting process might affect the quality of that embryo or the future health of the baby that it might develop into.

Why use an embryo that has been manipulated when there are plenty of pristine surplus IVF embryos available?

Some Christianist zealots might volunteer to gestate post-harvest embryos, but I would argue that such a decision would be unethical, especially if they believe that all surplus IVF embryos have equal moral status. If they want to "save" surplus embryos, they should save the ones that have the best chance at healthy lives.

"It would be unethical to gestate an embryo that had been tampered with in that way.

We don't know how the harvesting process might affect the quality of that embryo or the future health of the baby that it might develop into."

First, I won't argue with the second part (re: "pristine" IVF). But I'm a little confused by the argument that this is unethical. We don't know a lot of things about medical procedures when they first are created. Sticking to gestation, there were similar fears about ultrasounds and IVF techniques in general. Does that make having an ultrasound today unethical? Did it make them unethical decades ago when the technology was introduced?

Moreover, one can currently genetically test IVF created embryos. This tampers with the single cell which might (who knows?) have adverse effects down the road. By the same arguement, it should be considered unethical to carry to term. Is that really the argument you are making here or am I misreading?

It's only acceptable to subject patients (or future patients) to risks when there are compelling reasons to do so.

Initially, we didn't know whether IVF babies would be healthy, but we knew for sure that certain couples would otherwise be infertile. We had no reason to assume that IVF babies would suffer, and these couples needed help. So, it became ethical to obtain informed consent for what was then an experimental procedure.

There's just no good reason to start experimentally gestating blastocysts that have already been harvested for stem cells.

There's risk, but no countervailing benefit to the future baby or the parent. In the best case scenario, babies who came from pre-harvested embryos will be as healthy as those from pristine embryos.

Unless there's a shortage of pristine embryos there's no reason to start with the ones of questionable quality.

Some Christianist zealots might volunteer to gestate post-harvest embryos, but I would argue that such a decision would be unethical, especially if they believe that all surplus IVF embryos have equal moral status. If they want to "save" surplus embryos, they should save the ones that have the best chance at healthy lives.

It would be unethical for you to do it, but for someone who believes that all human lives are equally valuable, having the best chance at a healthy life is not a part of the ethical framework used to make the decision, making this not an ethical violation (or likely a lesser ethical violation than allowing a "human life" to be flushed down the sink). Under your reasoning, a mother would be behaving unethically by carrying to term a "defective" embryo, say a child that will have Down's syndrome child.

I wish a smartass scientist create a total synthetic blastocyte already. I am getting sick of this embryo this, embryo that.

Let the religious wackos sort it out if an embryo grown from a total synthetic blastocyte is a person or not. (If you ask me, yes it is a "potential" person. But I just love the idea messing with religious wackos world view)

And frankly, those theocrats bastards are getting pretty old. sooner or later they gonna need body parts grown from stem cell research. I couldn't wait for the day when I can say "I thought you bastards don't agree about stem cell research. Can you not die already instead of seeking advance medical cure? ... Hey, Ronald reagan was feeling the need for those technology... What makes you think the younger tehocrat bastards like pat robertson won't beg for it 10 years from now when entropy finally gets to his biological system.)

bastards...

(yeah I know I am a bit riled up.)

~~~ Under your reasoning, a mother would be behaving unethically by carrying to term a "defective" embryo, say a child that will have Down's syndrome child.
Posted by: agm | October 17, 2005 at 04:37 PM ~~~~

Except we cannot intrude upon a womans right to decide, hence that argument is moot.

In case of IVF, the embryo is outside any adult body. Somebody got to make the decission. And that person doesn't hve natural right to decide unlike a 'mother'. The situation is new condition only exists because of new technology. Hence it requries new set of considerations.

If you're being really technical, "embryo" isn't quite the right word either. We're probably talking blastocysts here.

According to the article:


They let a fertilized mouse egg divide three times until it contained eight cells, a stage just before the embryo becomes a blastocyst.

As with "ovum", "embryo" is a term that can cover a number of stages of development.

Nobody would want to gestate an ovum after it had been raided for stem cells.
(Specifically, an eight-cell almost-blastocyst which has been reduced to seven cells.)

Perhaps not, if the purpose of the raid was not for the benefit of the potential offspring. However, according to the article:


The seven-cell embryo was implanted in the mouse uterus and grew successfully to term. This part of the procedure is known to work with humans too, because it is the basis of a well-established test known as preimplantation genetic diagnosis. In the test, one cell is removed from each of a set of embryos and tested for any of 150 genetic defects, giving the parents the choice of implanting an embryo that is disease free.

So it seems that people are doing it when the objective is to improve the odds of a healthy offspring.

This could be called "the ends justify the means" or, for Catholics, "the Principle of Double Effect."

1) seconding Ted's comment, as the article points out, embryos that have had individual cells removed are implanted all the time;

2) However, Ted, you're wrong to equate the principle of double effect with "ends justify the means". The principle of double effect holds that when there are two possible ends, one of which is morally acceptable and one of which is not, as long as the intent is for the morally acceptable, the means are justified. For example, administering pain medication in a dose that will most likely shorten a suffering patient's life is not considered euthanasia if the intent is to alleviate pain rather than end the life.

For another example, the one I already gave: interfering with the embryo to get a line of stem cells for some organization's use, versus doing so to improve the odds of a healthy offspring.

Incidentally, all you wrote was:
(1) You're wrong.
(2) This is what the P of D E is.

You neither characterized what TEJTM means to you, nor drew any distiction between that and TPoDE.

Squashed Lemon, you're right, using the term mother is maladroit. Suppose that the right to decide were restricted to the egg donor (including the right to transfer to control of the eggs to another person). That person would be making a decision about her body, triggering the cover of right-to-decide. Of course, then we have to do a matching controls enforcing the right-to-decide for sperm donors, if nothing else specifying that they are transfering control of the donated cells to the sperm bank/IVF clinic/whoever.

Your statement thus supports my point. It would not automatically be an ethical violation in all circumstances for a woman to carry such an almost-blastocyte/modified embryo/whatever appropriate term in this circumstance (and this circumstance is likely to arise, since the egg and sperm have to come from somewhere).

Ted's right -- it's not that stem cells are harvested from the embryo (or whatever you want to call it), it's that a single cell is taken from the embryo, the same process used for preimplantation genetic diagnosis. With PGD, the single cell is then screened for genetic abnormalities; with this new stem cell technique, the cell is used as a source of stem cells. PGD is done with the specific intent of implanting the embryo if it proves to be free of genetic abnormalities, and it doesn't seem to result in any developmental harm. Implanting an embryo from which one cell had been taken to generate stem cells wouldn't be any different than implanting one after PGD.

PGD, by the way, is still not all that common -- there are only a few IVF centers in the country that do it on a regular basis. It's also not foolproof, only about 90% effective.

That is, PGD is only about 90% effective in ruling out genetic abnormalities. I think the success rates for IVF with PGD are essentially the same as with "regular" IVF -- somewhere around 30-50% on each try, depending on various factors.

Why not harvest numerous stem cells by harvesting umbillical cords? Wouldn't it be easier?

~~~Why not harvest numerous stem cells by harvesting umbillical cords? Wouldn't it be easier?

Posted by: suzib | October 18, 2005 at 09:04 AM~~~

They are not the same. 'Stem cell' is a class of cells, not just a single type of cell.

stemcells inside umbillical cord is farther down the line compared to blastocysts. umbilical cords primarily is good for blood related transplant.

Altho' we really don't know the precise details.

~~~Your statement thus supports my point. It would not automatically be an ethical violation in all circumstances for a woman to carry such an almost-blastocyte/modified embryo/whatever appropriate term in this circumstance (and this circumstance is likely to arise, since the egg and sperm have to come from somewhere).
Posted by: agm | October 18, 2005 at 12:19 AM ~~~

Very true. it would not be an ethical violation in that particular case. Since to me at least, it's a simple matter of releasing the right to decide from the original donor to herself.

But that condition is not automatic. It seems there is no standard record keeeping. Heck, we don't ven know what these cells are legally speaking. (Do we make somebody a guardian as in child with missing parents? or is it just cellular material, another property?)

It's pretty interesting situation really.

~~~ Unless there's a shortage of pristine embryos there's no reason to start with the ones of questionable quality.

Posted by: Lindsay Beyerstein | October 17, 2005 at 03:22 PM ~~~

lol. for some reason that tickles my brain.

I am imagining a gal sitting, looking at a microscope and saying. 'questionable quality. next. get me one in tip-top shape. I want one that wave flag at me.'

I am imagining a gal sitting, looking at a microscope and saying. 'questionable quality. next. get me one in tip-top shape. I want one that wave flag at me.'

Well, not exactly. But they do grade the blastocysts according to various criteria and implant the best ones they have, since those are the most likely to "take."

The entire stem cell debate is problematic considering that banning stem cell research won't save a single embryo, even without this new breakthrough. You could field an argument that it'd be unethical to extract fat from gassed Jews to make soap because it supports the extermination, but I don't see any opponents of stem cell research make that argmuent (and anyway I think it's flawed, but that's debatable).

Posted by: Alon Levy | October 18, 2005 at 01:52 PM

I always thought the biggest argument against stem cell is we really don't know what we are doing. (what become of all our creation when we finally clone a person. What is the faith of humanity if there is massive gene line contamination)

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