Thursday, June 21, 2007

Pluripotent vs embryonic stem cell reseach

The US President, George W Bush, has just—once again—vetoed a bill that would allow federal funding for embryonic stem cell (ESC) research. While it's probably not surprising, given his nominally pro-life voting records, it's curious why the same bill is "resurrected" over such a short period of time. So it got me started to read some recent news about ESC.

Some curious facts and issues surrounding this veto:

1. Renaming of the "Human Embryonic Stem Cell Registry" to the "Human Pluripotent Stem Cell Registry"

Along with the veto, he also signed an executive order, in support of so-called "pluripotent" stem-cell research— touted as alternative, ethical, sources of stem cell research.

2. Definition of Pluripotency

If my limited knowledge and memory serve me right, the term 'pluripotent' is typically applied to non-embryonic stem cells. An embryo is made up of totipotent cells, which contain the complete genetic information needed to 'manufacture' all the cells of the body, as well as pluripotent & multipotent cells. To simplify the meaning of this terminology: totipotent cells are found in the earliest stages, the pluripotent cells are found after 3 or 4 divisions, and multipotent cells are created after further divisions. Totipotent, pluripotent, and multipotent cells are all present in the embryo, but only pluripotent and multipotent cells can be found in adults.. How they differ exactly and why most supporters of ESC seem to be after the highly plastic ESC, are beyond my field.

It just seems as if the use of this term is deliberate, to stress that the source of this line of stem cells is not embryonic.

3. Definition of Embryo

The article above, seems to highlight recent discoveries of making adult stem cells behave like ESC through a process called "altered nuclear transfer". While stem cells obtained through this way is not technically destroying human embryos, there is a question of whether the adult cells reprogrammed to act like embryonic stem-cells are 'sometimes able to develop into full embryos again' by a process known as "regulation" - then what is present is potentially a human being... which makes this line of stem cells no different than ESC.

4. Definition of Life

It seems to me that restricting federal funding for ESC research is not sufficient if Bush truly believes that ESC are indeed human beings at embryonic stage! To still allow ESC research on private funding would be like saying, privately-funded killing is morally fine but the state will not fund such deeds. The supporters of ESC research would see through this duplicity and keep pushing the bill. To be consistent to the definition of life ("life begins with love"--George W Bush, 2006) at conception, it demands no less than a total ban.

Some links to articles that summarize the reprogramming of adult stem cells (in mice): here, here and here.

And a link to article about using the morality of using 'dead' ESC here.

More articles here & here.

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