Tuesday, October 18, 2005

"new" method of extracting stem cells still problematic

It was reported yesterday that two “new” scientific techniques of obtaining stem cells from embryos have been developed. I'd like to talk about one of them, because the other has been dealt with on this blog already.

This "new" technique involves extracting a single cell, called a blastomere, from a few- days-old embryo, just before it reaches the blastocyst stage.

This single cell retains the ability (pluripotency) to form other cells that have all the same essential properties as embryonic stem cells derived from the inner cell mass.

Meanwhile the embryo, minus the one extracted cell, will then be implanted back into the mother and allowed to mature.

According to Robert Lanza who pioneered this technique: “The most basic objection to embryonic stem cell research is the fact that embryos are deprived of any further potential to develop into a complete human being."

He adds that: “We have shown in a mouse model that you can generate embryonic stem cells using a method that does not interfere with the developmental potential of the embryo. It is important to note that this work was performed in the mouse and needs to be extended to the human species. It would be tragic not to pursue all options and methods available to us to get this technology to the bedside as soon as possible.”

Actually, the Church's objection to embryonic stem cell research is not only because it "deprives that embryo of any further potential to develop into a complete human being," but also because of the importance of preserving its dignity and integrity.

Part of this "new" technique is not really new. The “extracting” phase is called pre-implantation genetic diagnosis, commonly used by folks using in-vitro fertilization (IVF) to check if their embryo is defective.

The extracted blastomere is checked to see if the embryo as a whole is viable and healthy. If not, it’s flushed down the toilet.

The new variation here is taking that extracted blastomere and allowing that to develop various stem cells for therapeutic purposes.

Frankly, I have trouble with that technique, because of the extraction. What does that extraction really do to the integrity of the whole embryo? Many scientists have said it has had no adverse effect on the fetus and on the child born. But is that really for sure?

There is no hard evidence for this, according to Kathy Hudson, director of the Genetics and Public Policy Center at Johns Hopkins University. She has said to the NYT that there was "little data that documents the safety and efficacy" of the preimplantation diagnosis procedure, even after 2,000 births.

She then urged the American Society for Reproductive Medicine to create a national database to address the safety issue.

This all seems rather dubious. The Church has already voiced its opposition to the IVF procedure of pre-implantation genetic diagnosis because it compromises the integrity and dignity of the embryo.

Additionally, how about the potentiality of that blastomere? I have seen reports indicating that in some cases these blastomeres have been implanted into the womb of an experimental animal and have matured into fetuses.

This “new” procedure, far from “solving” the ethical dilemma surrounding embryonic stem cell research, seems to bring more questions and problems.

It’s still best to be guided by the words from the Vatican's Congregation of the Doctrine of the Faith's Donum Vitae:
No objective, even though noble in itself, such as a foreseeable advantage to science, to other human beings or to society, can in any way justify experimentation on living human embryos or foetuses, whether viable or not, either inside or outside the mother's womb. The informed consent ordinarily required for clinical experimentation on adults cannot be granted by the parents, who may not freely dispose of the physical integrity or life of the unborn child. Moreover, experimentation on embryos and foetuses always involves risk, and indeed in most cases it involves the certain expectation of harm to their physical integrity or even their death. To use human embryos or foetuses as the object or instrument of experimentation constitutes a crime against their dignity as human beings having a right to the same respect that is due to the child already born and to every human person.

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