'Ethical' stem cell lines created ~~ Technology removes an ethical dilemma?

BBC ^ | Wednesday, 23 August 2006, 17:12 GMT 18:12 UK | BBC staff

[Ernest_at_the_Beach]

Last Updated: Wednesday, 23 August 2006, 17:12 GMT 18:12 UK

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'Ethical' stem cell lines created

The scientists removed single cells from the embryos

Human embryonic stem cell lines have been generated without embryos being destroyed, according to researchers.

A US team created stem cell lines by removing single cells from embryos, a process that left them intact, they report in the journal Nature.

At present, growing this type of stem cell results in embryo destruction.

The researchers say their findings may remove some of the ethical barriers to this field and provide a way of bypassing current US legislation.

	Under US law, federal funding is limited for research in which an embryo is destroyed. Clearly this approach does not involve the destruction of an embryo Professor Robert Lanza

In 1995, the US congress passed an amendment stating that the government would not fund research in which human embryos were destroyed.

And in 2001, President Bush declared federal funding would only be available for research using the 61 human embryonic stem cells lines already in existence, where a "life or death decision had already been made".

This meant that no new lines could be created, whether from existing embryos or cloned embryos.

US stem cell researchers said the funding limits had ensured the US lagged behind in this field of research, limiting new studies to private companies, while pro-lifers hailed the decision.

Scientists believe stem cells may one day help to combat a range of diseases, such as Alzheimer's or Parkinson's disease, or to repair spinal cord injury.

'Ethical barriers'

But Professor Robert Lanza, medical director of biotech company Advanced Cell Technology (ACT) in Massachusetts, US, and lead author on the paper, said: "We have shown for the first time you can create human embryonic stem cells without destroying the embryo and thus without destroying its potential for life."

Using spare human IVF embryos, the researchers removed single cells from them, employing the same procedure used for pre-implantation genetic diagnosis (PGD), a technique that has been used in IVF so cells can be removed from the embryo and tested for genetic disorders.

The process, said the team, leaves the embryo intact, enabling it to continue and grow into a healthy foetus.

Of the 16 embryos used, they developed two long-term stem cell lines, which, Professor Lanza said, were "genetically normal and able to generate all of the cell types of the body".

If the research is successfully replicated by other scientists, this could mean more stem cell lines for research and potentially tailored stem cell lines which could be used for children born through PGD.

Professor Lanza added: "We hope this method can be used to increase the number of stem cell lines available for federal funding, and thus give the field a badly needed jump start."

Limited relevance

However, David Christensen, from the Family Research Council, a US-based conservative group, said: "What is good about this research is that it shows many more researchers are seeing that we need alternatives to destroying human embryos to get stem cells.

I am unconvinced by the ethical arguments - spare IVF embryos used to derive the cell lines would have been destroyed anyway Professor Robin Lovell-Badge

"Unfortunately what Professor Lanza did was entirely unethical because he generated and manipulated 16 human embryos and then threw them all away."

Other scientists said while the paper marked a technical achievement, they were concerned about its practical relevance.

Professor Robin Lovell-Badge, head of developmental genetics at the UK's MRC National Institute for Medical Research, added: "I am also unconvinced by the ethical arguments - spare IVF embryos used to derive ES cell lines would have been destroyed anyway."

Professor Chris Shaw, a neurologist at the Institute of Psychiatry, King's College London, said: "This is a useful alternative source for embryonic stem cells but it side-steps the crucial ethical question: 'What happens to those embryos found to have a genetic mutation and those that are healthy but excess to requirement?'"

[weegee]

And in 2001, President Bush declared federal funding would only be available for research using the 61 human embryonic stem cells lines already in existence, where a "life or death decision had already been made".

This meant that no new lines could be created, whether from existing embryos or cloned embryos.

AND receive federal funding.

The media loves to obscure that part.

[mvpel]

Professor Robin Lovell-Badge, head of developmental genetics at the UK's MRC National Institute for Medical Research, added: "I am also unconvinced by the ethical arguments - spare IVF embryos used to derive ES cell lines would have been destroyed anyway."

[tallhappy]

A US team created stem cell lines by removing single cells from embryos, a process that left them intact, they report in the journal Nature.

If one removes a cell from an embryo they are no longer "intact".

The consequence of such cell removal on the the further development of the organism is the question. It might have profound consequences.

Even amniocentesis which is done in utero and removes only cells from amniotic fluid has a certain rate of inducing birth defects.

At a much earlier stage of development with many less cells, taking one might make the leftover completely non-viable.

Perhaps these questions are addressed in the article, but that would mean mouse experiments.

[eraser2005]

ping for later reading

[Question_Assumptions]

So long as that single cell could, in theory, mature into a baby (as such cells do during twinning), arguably it's still detroying a baby.

[GovernmentShrinker]

PGD on IVF-derived human embryos prior to transfer into the mother's uterus is a routine procedure. There are lots of normal healthy children running around who had one cell plucked at this stage. And some who had a cell plucked, and were then frozen for future use, because there were too many normal embryos to safely transfer into the mother at one time, and then thawed and transferred later.

[Question_Assumptions]

While I agree that there is a profound risk of damaging the embryo by removing a single cell at such an early stage, I think the more troubling question is whether that removed cell has the capacity to develop into a baby and, if so, they are just creating a twin and killing the twin.

[GovernmentShrinker]

That is the problem with the whole notion of regarding embryos as individual human beings. In fact, they are collections of raw materials which could still become one person, multiple persons, or a part of a person (at this stage, you can still squish two embryos together and get a single baby with mixed DNA -- happens naturally fairly often, though apparently less often than monozygotic twinning).

So far, I don't believe anyone has gotten a single cell plucked from an embryo to develop into a baby (even a baby mouse), though it may eventually be possible. I think a bare minimum of two cells is needed, because once the zygote has divided, the groundwork for inter-cell signalling about which cells will become up/down/right/left parts of the body is being laid, and the process doesn't seem to work with just one cell.

[tallhappy]

Thanks for the info. I also saw that this group earlier (in January) published an article addressing this.

[tallhappy]

the groundwork for inter-cell signalling about which cells will become up/down/right/left parts of the body is being laid, and the process doesn't seem to work with just one cell.

This is why it seems counterintuitive that removal of a cell would not have an effect on development.

[tallhappy]

Interesting question and addressable at many levels.

I agree with the technical comments made by Government shrinker relating to this.

[Sgt_Schultze]

Professor Robin Lovell-Badge, head of developmental genetics at the UK's MRC National Institute for Medical Research, added: "I am also unconvinced by the ethical arguments - spare IVF embryos used to derive ES cell lines would have been destroyed anyway."

Hmmm. By this reasoning, medical experimentation on convicts facing the death penalty would also be ethical, as those lives are facing destruction.

[VOA]

This possible development was mentioned in (IIRC) the Dec. 2005 "Smithsonian" magazine.
It was a pretty fair and balanced article; and honest about the haggling between
even scientists that have varying ethical viewpoints.

I just happened to be viewing the mag yesterday.
And couldn't help having a small smile when reading the part about how that
South Korean cloning-miracle-worker was leaving the stodgy old USA in the dust.

[GovernmentShrinker]

If there are two, they can signal each other. Keep in mind that in the case of identical twins, they have each lost a lot more than one of their original cells, and yet turn out perfectly normal. At this stage, none of the cells are committed yet to being up/down/right/left. If two cells are adjoining each other, and the contact causes them each to pump a chemical signal across the membranes into the other cell, then a chemical gradient would result (higher concentration on the side of the cell that is contact with the other cell) -- this can't happen with a single cell. I'm not saying that's exactly how it happens, but that's the basic concept of how cells communicate with adjacent cells and affect each others growth and activity.

The research on these mechanisms is progressing, but there's still a lot to learn.
http://www.sciencedaily.com/releases/2005/03/050309130549.htm

What's actually even more complicated is how the asymmetrical organs develop after a basically symmetrical body has been set up.
http://www.sciencedaily.com/releases/2006/04/060419083112.htm

[ga medic]

There are over 1,000 children that have already been born, after the performance of this procedure. (from 6,500 IVF cycles) While long term studies haven't been done, it appears to have little affect on the embryo. Google pre-implantation genetic diagnosis. There is a lot of info out there.

[Ernest_at_the_Beach]

I am a novice on this whole are,....turned this up while searcghing for PGD:

Preimplantation Genetic Diagnosis and Human Implantation—A Review

************************AN EXCERPT ***********************************

Reduction of multiples and frozen embryos PGD of aneuploidy may also help reduce the number of multiple pregnancies. In the two latest studies involving a test and a control group, significantly fewer embryos were trans- ferred in the PGD groups than in control groups (Gianaroli et al., 1999; Munné et al., 1999, 2003; Werlin et al., 2003). In addition, because many embryos are abnormal, after PGD there are fewer chromosomally normal embryos remain- ing in excess of those for replacement. Therefore there are very few embryos freezable, which will alleviate the problem of accumulating, storing and eventually disposing of unwanted frozen embryos

[tallhappy]

What is the time frame of the embryo from which the cell is removed? How old is it in other words? How many cells total?

[GovernmentShrinker]

This is why PGD is becoming more and more routine (originally it was used only where one or both parents carried a serious genetic disease). Most embryos are abnormal -- not just "not perfect", but not capable of developing beyond the first days or weeks of pregnancy. In young women about half are normal; in women over 40 about 10% are normal (with wide individual variation of course). In IVF without PGD, this means that in order to have a reasonably good chance of producing one baby, 2-5 embryos are transferred (number depending mostly on the mother's age).

But the laws of chance and unpredictable individual variation result in some high order multiple pregnancies which often end disastrously. While PGD doesn't provide a 100% guarantee of a baby, it greatly reduces the problem of multiples, and of the emotional strain of miscarriages in women who have usually already been through a lot of strain over years of unsuccessful efforts to have a baby.

[ga medic]

The procedure is typically performed on an embryo at the 4 to 10 cells stage of development. For the purposes of PGD one or two cells are removed. I would estimate that an embryo would reach the 4 to 10 cell stage at about 3 days after fertilization, but I don't know for sure.