miércoles, 18 de mayo de 2016

MercatorNet: Scientists call for embryo experiments

MercatorNet: Scientists call for embryo experiments

Scientists call for embryo experiments

No tinkering with embryos over 14 days used to be the rule. Until now.
Xavier Symons | May 17 2016 | comment 2 

Policy analysts in the United States and United Kingdom are calling for an augmentation of the decades-old 14-day embryo experimentation rule - a regulation that requires scientists to terminate any embryo in vitro before it reaches two weeks of development.
The calls for change have come in the wake of the publication of ground-breaking embryology research in the journal Nature.
In two separate studies, scientists have reported keeping embryos alive, healthy and developing up until the 14-day mark.
In both studies the embryos grew autonomously and began the initial biological processes that lead to organ development -a major improvement on any previous in vitro experiment.
With similar calls for regulatory reform doubtless in store for Australia, it's time we took a good look at why we have the 14-day limit and, indeed, whether we should have it.
The origins of the 14-day rule
All Australian states currently have legislation that prohibits the experimentation on human embryos in vitro beyond the 14-day mark. The state legislation was drafted following a 2002 Council of Australian Governments (COAG) meeting, in which it was decided that States and Territories would introduce nationally consistent legislation to ban human cloning and other unacceptable research practices involving excess assisted reproductive technology (ART) embryos.
To trace the history a little further, the COAG agreement came following a 2002 federal parliamentary enquiry into cloning and embryo research. That enquiry recommended the 14-day rule based on scientific observations about the stage in embryo development when "a primitive streak, the first confirmation of the organised embryo and its orientation, is formed."
Many, if not most, members of the scientific community claim that, based on current knowledge about embryology, the 14-day mark is when a individual organism arises. The so-called "primitive streak" is a faint band of cells marking the beginning of an embryo's head-to-tail axis, and it would appear to indicate the emergence of a unified and autonomous organism.
One could speculate about the multiplicity of reasons why policymakers saw the moment of autonomous development as significant. Yet from reports like the UK's 1984 Warnock Report, it seems we can narrow down the ethical concerns of committees to two broad viewpoints.
First and foremost, many members of bioethics committees subscribe to what is often called the "potentials" view about the moral status of human beings. Broadly speaking, this is the view that having the potential to develop the qualities characteristic of human beings is what gives an embryo the same intrinsic moral standing that we attribute to a fully functioning adult human being (the latter being, arguably, the archetype of a human). On this view it is not the possession of capacities like rationality that gives a human being moral status; rather, it is the metaphysical potential to develop such capacities.
If one adopts the potentials account of human moral status, then any individual human being, be it a healthy adult or a nascent embryo, has moral status. Hence, if indeed an individual autonomous embryo arises at 14 days, then it is at this point that we should prohibit experimentation on human embryos; the embryos should be destroyed before such time as they become self-directing organisms.
The second viewpoint, rather than being a particular stance on the moral status of the embryo, is rather a view about the way bioethics policy should be done in a pluralist society. The view - a perspective that strikes me as quite Rawlsian - is that bioethical policy should be based on points of convergence between rival philosophical and religious worldviews. Our bioethical policy should aim at creating, to quote the Warnock Report, "a kind of society that we can, all of us: praise and admire, even if, in detail, we may individually wish that it were different."
Medico-ethical policy should, in other words, be sufficiently broad to allow space for reasonable disagreement between the rival viewpoints of the members of society.
Concerning embryo research, this view leads one to avoid what are perceived as two extremes - a total ban on research using human embryos in vitro, and the total absence of restrictions of research. The so-called 14-day rule was seen by committees as policy for embryo research that was both a pragmatically useful and conciliatory.
Arguments for changing the regulation
The main argument being advanced for changing the rule is that there are immense scientific benefits to broadening the scope of embryo research. In classic utilitarian style, proponents of this argument emphasize that there is much to be learnt from embryo experimentation beyond the 14-day mark, and the promises of this research outweigh any countervailing considerations.
University of Manchester bioethicist John Harris, for example, argued in Guardian that a switch to a 21-day deadline would allow scientists to better understand miscarriages and the possibilities of using stem cells to treat diseases:
"The overwhelming consensus of scientific opinion, as of this week, is that much of considerable scientific and therapeutic importance can be learned by extending the 14-day limit for a further week, to 21 days ..."
Harris claims that the potential negative effects of such research are negligible, and should not weigh heavily in our calculus.
Another argument, quite different from the utilitarian claim, is what we might profitably call the sociological argument: social values have changed so dramatically that it is appropriate to change the law as well - and this particularly if our laws are intended to be a "compromise" between rival viewpoints. If indeed our original embryo research policy was intended to be a sort of compromise between rival viewpoints and the interests of science, then perhaps it is appropriate that we adjust the conciliatory regulations to fit with changing social morality as well as new goals in science.
Writing recently in Nature, three respected US bioethicists advanced a variant of this argument:
"The 14-day rule was never intended to be a bright line denoting the onset of moral status in human embryos. Rather, it is a public-policy tool designed to carve out a space for scientific inquiry and simultaneously show respect for the diverse views on human-embryo research ..."
Harris suggested that the original regulation was based on an outmoded an arcane view about ensoulment and embryos: "the time has come," Harris suggests, "to change the rules to enable research that is fully consistent with our values."
An alternative view
The prevailing view at the moment is that the flaws of the 14-day rule give reason to augment the time allowed for experimentation. Yet it is peculiar that few have considered the opposite conclusion.
Bioethicists who subscribe to the so-called "potentials" view may very well suggest that the arbitrary law gives reason to restrict rather than liberalise our regulations. Indeed, this is the view of bioethicists like Reverend Tadeusz Pacholczyk of the US National Catholic Bioethics Center, who argues that the original law only paid "lip service to the moral status of the human embryo."
On this view it is the moment of conception in which a human being comes into existence, and thus any experimentation on human embryos, with the view to terminating those embryos, is illicit.
I am very sympathetic to the latter view, though no doubt many, if not most, would take issue with it. Pragmatically, there is one procedural observation about law reform that hopefully everyone can agree on: if any medico-ethical legislative reform is considered, there is need for widespread and extended consultation with professionals involved in healthcare as well as ethicists, legal experts and the general public.
It was alarming to see how hastily the UK Human Fertility and Embryology Authority authorised gene-editing research on human embryos. Hopefully more time is given when it comes for Australia to consider the ethical implications of new developments in embryology research.
Xavier Symons is deputy editor of BioEdge and a research associate with the Institute for Ethics and Society at the University of Notre Dame, Australia. This article has been republished from the ABC website with the permission of the author. 
- See more at: http://www.mercatornet.com/articles/view/scientists-call-for-embryo-experiments1/18076#sthash.Pxy0343A.dpuf

I always understood that stem cell researchers were banned from allowing human embryos to grow in a Petri dish for longer than 14 days. Around the world this bright line was either a law or a scientific guideline. I don't believe that embryos should be grown in Petri dishes or experimented on at all, but the idea that scientists believed insome limit was a comforting sign of respect for human life. 
How ignorant I was. It turns out that the longest time that an embryo had ever grown in a Petri dish was 9 days. It was easy to observe the limit because it was unreachable anyway. Praising researchers' restraint was like awarding medals for services to endangered species to hunters who refuse to kill unicorns. Earlier this month, however, researchers announced that they had grown embryos for 13 days. Immediately, leading scientists suggested that the 14-day rule be revisited. No doubt this will happen quickly unless there is a robust debate. Below, Xavier Symons discusses some of the ethical complications. 

Michael Cook 

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