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Wednesday, 10 January , 2007 / ermes

“New Frontier” for stem cells research?


From The Indipendent on line edition, 10 January 2007:

The Big Question: Should we allow the creation of embryos which are animal-human hybrids?
By Steve Connor, Science Editor

Why does the question arise now?

The Human Fertilisation and Embryology Authority (HFEA) is meeting today to decide whether to allow scientists to use animal eggs for the creation of “hybrid” human embryos. By removing the cell nucleus of a cow or rabbit egg and inserting the nucleus of a human skin cell into the empty “shell”, it is possible to create a cloned embryo that is 99.5 per cent human and 0.5 per cent animal in terms of its total genetic complement. The current Human Fertilisation and Embryology Act, drawn up more than 16 years ago, does not cover this new technique, so the authority has to decide whether it falls within the current law.

Would the embryos be ‘chimeras’?

Technically, a chimera is an organism comprised of a mixture of cells from two different species. In this case, however, all the DNA of the animal’s cell nucleus has been removed prior to the insertion of the human cell nucleus. The only genetic material of the animal left is the DNA of structures outside the nucleus called mitochondria, which are the power-generating part of the cell. So the resulting animal-human embryo is neither a chimera nor a hybrid – the result of cross-breeding. Such embryos do not have a scientific name, although someone has suggested “cybrid” because it merges the cytoplasm of the animal egg with the nucleus of the human cell.

Why create animal-human embryos?

Scientists want to use animal eggs to create cloned human embryos because of the shortage of human eggs for research purposes. A scientist can go to a slaughterhouse and acquire 200 good quality cow eggs in one day, whereas it would take a month to get just two human eggs for use in such research. The aim is to produce embryos at the six-day stage of development which can then be used in the production of embryonic stem cells. These cells have the ability to develop into any one of the many dozens of specialised tissues of the body – such as heart muscle, nerve cells or hormone-producing tissue. Scientists seeking permission to carry out this work emphasise that there is no intention of allowing these embryos to develop beyond the 14-day stage – which would in any case be illegal. Neither do they intend to use any of the resulting stem cells in the subsequent treatment of patients.

So why do scientists want them?

Stem cells acquired from animal-human embryos would be used for the fundamental understanding of diseases. The nucleus of a skin cell taken from someone suffering from Parkinson’s disease, for example, could be placed into the empty “shell” of a cow egg, and then cloned into a six-day-old embryo. If stem cells are then extracted from the embryo, they could be grown into mature brain cells affected by Parkinson’s. These cells could be used in experiments to shed light on the genetic nature of Parkinson’s brain cells by directly comparing them with normal brain cells. It could be possible to develop new treatments for many incurable and serious diseases, especially those with a strong genetic component.

Who wants to do this research?

Three groups:Stephen Minger heads a group at King’s College London that is particularly interested in creating embryonic stem cells from patients suffering from diseases with a genetic basis, such as Alzheimer’s, spinal muscular atrophy and Parkinson’s.

A second licence application has been made by Lyle Armstrong and colleagues at Newcastle University, who want to use the technique to study how stem cells develop into the different specialised tissues of the body. They hope to be able to grow these tissues for transplant operations.

Finally, a group led by Chris Shaw of King’s College London and Professor Ian Wilmut of Edinburgh University are considering to apply for a licence to use embryonic stem cells to help patients suffering from motor neurone disease.

Who opposes this work?

There are many pressure groups and religious organisations who have voiced their opposition on the grounds that it is unethical or immoral to mix germ cells from humans and animals to create potentially viable embryos. They believe that it undermines respect for human life, and some believe it is also demeaning to animals. But there is a body of expert opinion in academia and government that also appears to be opposed. For instance, a White Paper published at the end of last year on the review of the Human Fertilisation and Embryology Act said that it is the Government’s intention not to allow the creation of hybrid and chimera embryos in the laboratory. However, the Government said that it also proposes that the new law should contain a power that allows the creation of hybrid embryos under licence for certain research purposes.

A public consultation into the issue of creating embryos by combining animal and human material produced a massive response against such research. This is said to have spooked the Department of Health in particular into calling for an outright ban. Critics have argued, however, that the consultation had been hijacked by pressure groups opposed to all research on human embryos.

Nevertheless, a major report on stem-cell research in 2000 by a group of high-level experts led by Liam Donaldson, the Chief Medical Officer, concluded: “The use of eggs from a non-human species to carry a human cell nucleus was not a realistic or desirable solution to the possible lack of human eggs for research or subsequent treatment.”

Is this research allowed elsewhere?

China seems to be leading the field, having created human embryonic stem cells using rabbit eggs. American scientists have also claimed to have produced similar stem cells – although federal funding of such research is banned by the US Government. Many other countries do not have explicit bans on such research, although there are some notable exceptions such as Australia.

What is likely to happen today?

The HFEA will meet and discuss the ethical and legal implications of the work. The authority members will not look at individual licence applications yet, but instead will concentrate on whether or not to allow the research in general to go ahead. One possibility is that the authority will decide to issue temporary licences for six or nine months. Whatever the HFEA decide, it is bound to be opposed either by those supporting the work, or by those wanting it banned.

Are ‘hybrid’ human-animal embryos a good idea?

Yes…

* They allow scientists to produce embryonic stem cells for research purposes

* Animal eggs are in plentiful supply and hybrid embryos overcome the shortage of human eggs

* No one will allow them to develop beyond 14 days and the stem cells will not be used in medicine

No…

* It is immoral to mix animal and human stem cells, and is demeaning to life

* Stem cells can be extracted from adult humans, so there is no need to create embryos that are then destroyed

* Allowing such research is the slippery slope to the day when someone clones a hybrid embryo and implants it into a womb

28 Comments

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  1. NickPolitik / Jan 10 2007 12:35 PM

    ????????????????????????????????????????????????????????????????????????????????????????????????

    I’m very astound. But, at the same time, I’m afraid. At the moment I haven’t any opinion.

    But, the question is spontaneous: Is necessary to create this kind of problem? Phew!

  2. NickPolitik / Jan 10 2007 12:36 PM

    C’ho provato… l’inglese non è il mio forte!

  3. ermes / Jun 6 2007 9:01 PM

    Scientists Move Closer to Turning Skin Cells Into Tissues – Nicholas Wade, The New York Times June 6, 2007

  4. il maligno / Jun 7 2007 11:05 AM

    Scientists create embryonic stem cells without destroying embryos
    Researchers are ‘optimistic’ that the process can one day work in human cells
    David Cameron, Whitehead Institute
    June 6, 2007

    Scientists have created embryonic stem cells in mice without destroying embryos in the process, potentially removing the major controversy over work in this field. Embryonic stem cells are special because they are pluripotent, meaning they can develop into virtually any kind of tissue type. They therefore offer the promise of customized cells for therapy.

    The work, which appears in the June 6 online issue of Nature, was led by Rudolf Jaenisch, a member of the Whitehead Institute and a professor of biology at MIT. His colleagues on the work are from Whitehead, MIT, Massachusetts General Hospital, the Broad Institute of MIT and Harvard, and Harvard Medical School.

    Somatic cell nuclear transfer (“therapeutic cloning”) offers the hope of one day creating customized embryonic stem cells with a patient’s own DNA. In this process, an individual’s DNA would be placed into an egg, resulting in a blastocyst that houses a supply of stem cells. But to access these cells, researchers must destroy a viable embryo.

    Now, Jaenisch and colleagues have demonstrated that embryonic stem cells can be created without eggs. By genetically manipulating mature skin cells taken from a mouse, the scientists transformed these cells back into a state identical to that of an embryonic stem cell. No eggs were used, and no embryos destroyed.

    “These reprogrammed cells, by all criteria that we can apply, are indistinguishable from embryonic stem cells,” says Jaenisch.

    What’s more, these reprogrammed skin cells can give rise to live mice, contributing to every kind of tissue type, and can even be transmitted via germ cells (sperm or eggs) to succeeding generations. “Germline transmission is the final and definitive proof that these cells can do anything a traditionally derived embryonic stem cell can do,” adds Jaenisch.

    “But,” he cautions, “these results are preliminary and proof of principle. It will be a while before we know if this can ever be done in humans. Human embryonic stem cells remain the gold standard for pluripotent cells and it is a necessity to continue studying embryonic stem cells through traditional means.”

    In August 2006, researchers at Kyoto University reported that by activating four genes in a mouse skin cell, they could reprogram that cell into a pluripotent state resembling an embryonic stem cell. However, the resulting cells were limited when compared with real embryonic stem cells, and the Kyoto team was unable to generate live mice from these cells.

    How they did it
    The Jaenisch team decided to replicate this experiment, while refining certain technical aspects. This group included Jaenisch lab postdocs Marius Wernig, Alexander Meissner and Tobias Brambrink, MIT graduate student Ruth Foreman, Manching Ku, a research fellow from Bradley Bernstein’s lab at Massachusetts General Hospital, and Konrad Hochedlinger, formerly of the Jaenisch lab and now at Massachusetts General Hospital.

    Using artificial viruses called vectors, the team activated the same four genes in a batch of mouse skin cells. These genes, Oct4, Sox2, c-Myc and Klf4, are called transcription factors, meaning that they regulate large networks of other genes. While Oct4 and Sox2 are normally active in the early stages of embryogenesis, they typically shut down once an embryo has developed beyond the blastocyst stage.

    “We were working with tens of thousands of cells, and we needed to devise a precise method for picking out those rare cells in which the reprogramming actually worked,” says Wernig. “On average, it only works in about one out of 1,000 cells.”

    To test for reprogramming, the team decided to zero in on Oct4 and another transcription factor called Nanog. These two hallmarks for embryonic stem cell identity are only active in fully pluripotent cells. The trick would be to figure out a way to harvest Oct4- and Nanog-active cells from the rest of the population.

    The answer came in the form of a laboratory technique called homologous recombination. Here, the scientists took genetic material known to be resistant to the toxic drug neomycin and spliced it into the genomes of each cell right beside Oct4 and Nanog. If Oct4 and Nanog switched on, the drug-resistant DNA would also spring into action. The researchers then added neomycin to the cells. Only those fully reprogrammed cells with active Oct4 and Nanog survived.

    Next, the team ran these cells through a battery of tests, seeing if they could discover any substantial differences between these cells and normal embryonic stem cells.

    “In all tests…there were no molecular markers distinguishing these two groups,” says Meissner.

    But definitive proof would only come through demonstrating that these cells could actually develop into any kind of body tissue and cell type. The researchers approached this question in three ways.

    Definitive proof
    First, they fluorescently labeled these reprogrammed cells and injected them into early-stage embryos, which eventually gave rise to live mice. While these mice consisted of both the reprogrammed cells and the natural cells from the original embryo, the fluorescent tags indicated that the reprogrammed cells contributed to all tissue types in the mouse, everything from blood to internal organs to hair color.

    Next, they bred these mice and found lineages of the reprogrammed cells in the subsequent generation, proving that these new cells had contributed to the germ line.

    Finally, the team took advantage of another lab technique that involves creating a genetically abnormal embryo whose cells all consist of four chromosomes, rather than two. Because of this aberrant formation, the embryo can only form a placenta and cannot develop into a full-term fetus. The researchers injected the reprogrammed cells into this embryo and then implanted it in a uterus. Eventually live late-gestation fetuses could be recovered–created exclusively from the reprogrammed cells.

    “This is the most stringent criteria anyone can use to determine if a cell is pluripotent,” says Jaenisch.

    Still, many technical hurdles remain for possibly translating this work to human cells. For example, the homologous recombination technique used to isolate the pluripotent cells does not yet work in human embryonic stem cells.

    “We are optimistic that this can one day work in human cells,” says Wernig. “We just need to find new strategies to reach that goal. For now, it would simply be premature and irresponsible to claim that we no longer need oocytes for embryonic stem cell research.”

    This research is supported by the National Institutes of Health

  5. 666 / Jun 7 2007 11:06 AM

    Major progress toward cell reprogramming; researchers approach key goal of biologists
    By B.D. Colen

    Harvard News Office

    Two Harvard Stem Cell Institute (HSCI) researchers and scientists at Whitehead Institute and Japan’s Kyoto University have independently taken major steps toward discovering ways to reprogram cells in order to direct their development – a key goal in developmental biology and regenerative medicine.

    Additionally, the group led by Kevin Eggan, an HSCI principal faculty member – whose study is featured on the cover of the latest issue of the journal Nature – has disproved a long-held view of developmental biologists by demonstrating in mice that it is possible to use previously fertilized ova to produce disease-specific stem cell lines using somatic cell nuclear transfer (SCNT) – commonly referred to as therapeutic cloning.

    For almost three decades it has been a given in developmental biology that only unfertilized ova could be used to do SCNT, and difficulty in obtaining fresh ova has brought that work to a standstill. “Now we’re able to do an experiment a week, where we hadn’t been able to do a single experiment for a year,” Eggan said.

    In another approach to the problem of reprogramming cells, groups led by Kyoto’s Shinya Yamanaka, Rudolph Jaenisch of the Whitehead, and Konrad Hochedlinger of HSCI and Massachusetts General Hospital’s Center for Regenerative Medicine report the use of four genes to transform an adult cell into a cell with the properties of an embryonic stem cell – replicating and expanding upon seminal work published last year by Yamanaka. The Jaenisch and Yamanaka papers are being published in Nature; Hochedlinger’s is in the inaugural issue of Cell Stem Cell.

    HSCI co-director Doug Melton hailed the work, saying, “These new studies, done with mouse cells, point the way to experiments that can be tried with human cells and represent some of the most exciting work in stem cell biology and genetic reprogramming.”

    Commenting on Eggan and Hochedlinger’s work, Melton, the Thomas Dudley Cabot Professor of the Natural Sciences in Harvard’s Faculty of Arts and Sciences, said, “These exciting papers both address an important issue in developmental biology, namely, how can we change – or reprogram – a cell, turning it ‘back’ to a more embryonic state with a greater potential? The promise of both approaches is the possibility that we will be able to create embryonic stem cells from patients, and use those cells to study the root causes of degenerative diseases.”

    While all four reports are expected to cause enormous excitement in the stem cell and research communities, to a person the researchers are cautioning that thus far their studies have been conducted using mouse cells and mice, and there is no way to know whether they will translate precisely – if at all – to humans.

    “You can really turn back the clock from adult to embryonic” cells, said HSCI’s Hochedlinger, whose laboratory is at the Center for Regenerative Medicine at Massachusetts General Hospital. He cautioned, however, that “The limitations are we don’t know whether this reprogramming would work in humans; if it works, would it be the same factors, or are there different factors?” Success in humans, he said, would be “much more difficult to achieve than in mice.”

    Further, all three teams followed Yamanaka’s finding of last year by using retroviruses to introduce the necessary genetic factors into the target cells – and retroviruses are known to randomly turn on cancer genes. Thus, not only will scientists have to identify the factors that can reset the developmental clock in human cells – if there are such factors – but they will also need to find a different way to get those factors into cells, which may prove to be a daunting task.

    Eggan described his group’s study as “a good example of how things can change so quickly in a field.” He said that he and Dieter Egli, the study’s lead author and a postdoctoral fellow in Eggan’s lab, were “looking at a poster presentation at a meeting in Toronto and something just clicked – ‘Why,’ we asked, ‘does everyone think we need unfertilized eggs to do SCNT?'” That belief, he points out, was based on a very small number of experiments.

    Although Eggan and Melton received Harvard approvals a year ago to proceed with experiments using SCNT to produce stem cell lines containing the chromosomes of patients with diabetes and Parkinson’s disease, they were prevented for an entire year from conducting any experiments because of a lack of ova donors. “I don’t think it should be surprising that we don’t have any donors,” says Eggan. “Although the law in Massachusetts is broadly supportive of stem cell work, there is a real double standard – a woman can donate her ova to help another woman get pregnant, but she can’t undergo the exact same procedure for potentially lifesaving research and be compensated. So it was our desperation over the lack of ova donors that made us ignore 25 years of developmental biology and look for another solution.”

    The solution, the Eggan group found, is to remove the chromosomes from the fertilized egg – and replace them with the chromosomes from the donor cell – just at the point when the cell is about to divide for the first time.

    In past experiments, researchers had removed the intact nucleus, which may have contained factors necessary for the reprogramming of the cell, and thus those previous attempts at reprogramming failed. But by removing the chromosomes and not the nucleus, Eggan, Egli, and colleagues were able to reprogram cells that produced embryonic stem cells containing the genetic material of the donor cells.

    Eggan estimates that there is a substantial number of fertilized ova, or single-cell zygotes, in storage in fertility clinics, and has received all necessary approvals from Harvard Institutional Review Boards to begin experiments using them. While he has yet to have a single ova donation, Eggan said there are already couples donating frozen zygotes for research.

  6. ocinegsnart opot / Jun 7 2007 11:12 AM
  7. lagiardiaintroversa / Jun 9 2007 9:53 AM

    dal sito della UCLA
    Stem Cell Researchers Reprogram Normal Tissue Cells Into Cells With the Same Properties as Embryonic Stem Cells
    Researchers at the Institute for Stem Cell Biology and Medicine at UCLA were able to take normal tissue cells and reprogram them into cells with the same unlimited properties as embryonic stem cells, the cells that are able to give rise to every cell type found in the body.
    The work, done in mouse models, appears in the inaugural June 7 issue of the journal Cell Stem Cell, published by Cell Press. UCLA researchers, working closely with stem cell scientists at Harvard University, took mouse fibroblasts, cells that develop into connective tissue, and added four transcription factors that bind to special sites on the DNA. Using this process, they were able to turn the fibroblasts into pluripotent cells that, in every aspect tested, were identical to embryonic stem cells.
    The implications for disease treatment could be staggering. Reprogramming adult stem cells into embryonic stem cells could generate a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine. If the work can be replicated in human cells, it may mean that a patient’s skin cells, for example, could be reprogrammed to become embryonic stem cells. Those embryonic stem cells could then be prodded into becoming various cells types — beta islet cells to treat diabetes, hematopoetic cells to create a new blood supply for a leukemia patient or motor neuron cells to treat Parkinson’s disease.
    “If we can recreate this in human cells, it has significant implications for regenerative therapies,” said study co-lead author Kathrin Plath, UCLA assistant professor of biological chemistry and a researcher with the Institute for Stem Cell Biology and Medicine at UCLA (ISCBM). “Our reprogrammed cells were virtually indistinguishable from embryonic stem cells. We could find no evidence that they were different in any way. We were rather surprised at how well this reprogramming worked.”
    The finding also is significant in that this new technique could potentially replace a controversial method used to reprogram cells — somatic cell nuclear transfer (SCNT), sometimes referred to “therapeutic cloning.” To date, SCNT has not been done successfully in human cells.
    “If we can successfully reprogram a normal human cell into a cell with almost identical properties to those in embryonic stem cells without SCNT, it may have important therapeutic ramifications and provide us with another method to develop human stem cell lines,” said Dr. Owen Witte, ISCBM director and a Howard Hughes Medical Institute investigator. “Up until now, it’s been unclear whether a cell could be reprogrammed back into an embryonic stem cell state without the use of SCNT, so that makes this a very important finding.”
    Studies published previously had shown that the four transcription factors that regulate expression of downstream genes and either activate or silence their expression could reprogram cells into cells with some pluripotent properties. But they differed from embryonic stem cells in that they could not differentiate into every cell type or support development of adult tissues.
    “They had very limited developmental potential,” Plath said. “We took a different approach, carefully selecting from our pool of cells the reprogrammed cells that highly expressed two genes we know are essential in embryonic stem cells.”
    Selecting cells that highly expressed the genes Oct4 and Nanog, which are essential to giving embryonic stem cells their unique characteristics, resulted in reprogrammed cells with much more powerful pluripotency, Plath said.
    The reprogrammed cells were not just functionally identical to embryonic stem cells. They also had identical biological structure. In a cell nucleus, DNA — an organism’s unique map or instructions — wraps around histones, which serve as a kind of scaffolding for compaction of the long DNA molecule. Histones don’t merely package DNA. Chemical tags on histones determine which genes are expressed or shut off in the DNA. In the reprogrammed cells, the location of the chemical tags along the DNA chromosomes were identical to those found in embryonic stem cells and, just as importantly, dramatically different from those in the fibroblasts before reprogramming. The structure of the reprogrammed cells — down to the very small chemical tags that dictate gene expression — is highly similar to that of embryonic stem cells.
    Plath and her colleagues are working now to recreate the cell reprogramming in human cells. It could take years to determine if the same results can be achieved.
    About the Institute for Stem Cell Biology and Medicine at UCLA
    The Institute for Stem Cell Biology and Medicine was launched in 2005 with a UCLA commitment of $20 million over five years. With more than 150 members, the ISCBM is committed to a multidisciplinary, integrated collaboration between scientific, academic and medical disciplines for the purpose of understanding adult and human embryonic stem cells. The institute supports innovation, excellence and the highest ethical standards focused on stem cell research with the intent of facilitating basic scientific inquiry directed towards future clinical applications to treat disease. The institute is a collaboration of the David Geffen School of Medicine at UCLA, UCLA’s Jonsson Cancer Center, the UCLA Henry Samueli School of Engineering and Applied Science, and the UCLA College of Letters and Science.
    To learn more about the Institute for Stem Cell Biology and Medicine at UCLA, visit the institute’s Web site at http://www.stemcell.ucla.edu.
    -UCLA-

  8. Anch'io oggi sono uno stupido / Sep 6 2007 6:22 PM

    Atto mostruoso” certamente “contro la morale, non soltanto la morale cattolica o dei gruppi religiosi, dei gruppi pro-life, ma contro la morale razionale”.

    Ecco come si argomenta nei sistemi di pensiero chiusi ed autoritari: “il bene deve essere fatto con mezzi buoni”! Bella maniera di confrontarsi in modo pacato e dialogante.

    D’altronde, discutiamo di “pezzi di mucca”… Ed è chiaro che “studieremo il Parkinson nei cavalli”…

  9. Iperione / Nov 21 2007 11:44 AM
  10. Tony Abbacchiaty / Nov 21 2007 6:31 PM

    …io sono a lutto, per conto della giardiaintroversa. ancora una volta, uno scienziato che aveva adocchiato (W.Lensch) è diventato famoso. Lagiardiaintroversa vi augura che non sia una malattia trasmissibile, altrimenti siete spacciati.

  11. lagiardiaintroversa / Nov 22 2007 9:11 PM

    Ladies and gentlemen…Sir Paul Nurse, talking about cancer and stem cells, on Charlie Rose, few years ago.

  12. lagiardiaintroversa / Nov 23 2007 12:37 PM

    Stem cells research and ethical issues…on Charlie Rose. Alla faccia dell’Avvenire.

  13. lagiardiaintroversa / Nov 23 2007 1:09 PM

    Monster of Rocks on Stem Cells

  14. Tony Frizzantiny / Nov 23 2007 3:59 PM

    Chiedo scusa… ma non resisto…

    Paul Nurse = Robin Williams + fantastica cresta color argento!!!!!!

    Bidigoooooo Paul!

  15. Tony Brizzolaty / Nov 23 2007 5:47 PM

    …avevo evitato di farlo notare!!!

  16. Dina Sar / Dec 13 2007 9:59 PM

    La malafede, la disinformazione, la megalomania, la mania di protagonismo, la voglia di sentirsi utili al mondo a tutti i costi, il delirio di essere depositari di una Verità non conoscono confini. Sicuramente c’è poca differenza tra l’intelligenza di un embrione e quella della Roccella, se quello che capisce da un’intervista è questo. Meno male che c’è chi la demolisce.

  17. Pio Cap / Dec 22 2007 9:09 PM

    Bellissima intervista a Roger Pedersen

  18. lagiardiaintroversa / Jan 11 2008 9:15 PM
  19. Tina Assun / May 14 2008 6:35 PM

    dal mitico avvenire

    LONDRA E LA LEGGE SULLA FECONDAZIONE
    Il vezzo degli inglesi giocare a fare Dio
    ASSUNTINA MORRESI
    La settimana prossima il parlamento inglese esaminerà nel dettaglio il nuovo testo di legge che vuole regolare la fecondazione assistita e la ricerca sugli embrioni.
    Intanto però, due giorni fa, con una forte maggioranza è stato dato un via libera di massima all’intero impianto della nuova normativa. Nella fase successiva della discussione si prenderà infatti in esame il testo nel dettaglio, e sarà possibile inserire emendamenti. Il premier laburista Gordon Brown ha concesso libertà di voto ai parlamentari del suo schieramento nei tre punti più controversi: la creazione di embrioni misti uomo/animale (le cosiddette ‘chimere’); il via libera ai «saviour sibling», cioè i bambini concepiti in provetta su misura per poter curare fratelli o sorelle malati; l’ok alla fecondazione in vitro anche in assenza della figura paterna, una norma che riguarda per esempio le coppie lesbiche.
    Per far digerire misure di questo tipo la strategia è sempre la stessa: si afferma innanzitutto la propria contrarietà alla ricerca e alla fecondazione in vitro condotta senza regole, e poi si chiede di rendere legali le procedure più estreme e discutibili. Far nascere i «saviour babies» – detti anche «bambini-farmaco» – vuol dire creare in provetta un numero elevato di embrioni, selezionare quelli compatibili con la persona malata da curare e impiantarli in utero: gli altri si scartano, semplicemente perché non hanno il patrimonio genetico richiesto. Li si potrà forse ‘donare’ a coppie infertili, o mettere a disposizione della ricerca scientifica, o lasciarli congelati mentre si decide cosa farne. I «bambini-farmaco» sapranno forse un giorno di essere nati dopo avere superato una selezione, perché avevano il Dna ‘giusto’, proprio quello che serviva.
    Consentire a coppie lesbiche l’accesso alla procreazione in vitro, invece, significa cancellare il padre, con tutto quello che ne consegue sul piano simbolico e concreto. La figura paterna si riduce così a un fornitore di sperma, un numero in un catalogo di una biobanca. Non è una novità: negli Usa, dove i donatori possono rimanere anonimi, esiste il «1.476 group» che comprende i nati dallo sperma offerto alla Fairfax Cryobank dall’anonimo donatore 1.476. Nel loro sito Internet salutano i visitatori con un «Welcome to the Donor 1476 family site», benvenuti nel sito della famiglia del donatore 1476.
    Il figlio, purché voluto e desiderato, diventa quindi un diritto di chi lo vuole e lo desidera, ma nessuno si preoccupa dei diritti del figlio. E se queste persone, la cui vita è disegnata senza la presenza di un padre prima ancora del concepimento, un giorno rivendicassero il diritto ad avere quel papà deliberatamente cancellato da qualcun altro? Chi ha il diritto di stabilire che a loro non spetta un padre?
    C’è poi il nodo della creazione di embrioni ibridi uomo/animale: è per lo meno discutibile ostinarsi a presentare come ricerca scientifica di frontiera una procedura inefficace e oramai vecchia, la cosiddetta «clonazione terapeutica», tra l’altro mischiando Dna umano e animale.
    Si tratta di una strategia abbandonata dagli stessi che l’hanno promossa nel mondo, come lo scienziato Ian Wilmut, il ‘padre’ della pecora Dolly, e surclassata dalle nuove scoperte sulle cellule staminali pluripotenti indotte, quelle recentemente create dallo scienziato giapponese Shinya Yamanaka, per intenderci.
    Se la legge inglese verrà approvata senza emendamenti, sarà dunque lecito mischiare il Dna di esseri umani e di mucche, tanto poi – dicono i fautori – questo tipo di embrioni non è destinato a svilupparsi, saranno distrutti subito, servono solo per la ricerca… Se poi è una ricerca che non trova niente, che importa? Non si può nemmeno dire che c’è chi vuole – come dicono gli inglesi – «playing God», giocare a fare Dio. C’è infatti quantomeno da dubitare che il Padreterno intenda dilettarsi in simili attività di patchwork embrionale

  20. Satanasso / May 20 2008 5:16 PM

    da Avvenireonline del 20 maggio 2008

    IL VOTO INGLESE SUGLI EMBRIONI- CHIMERA
    La partita degli «ibridi» frontiera all’inaudito
    FRANCESCO OGNIBENE
    Ha appena subìto un memorabile rovescio elettorale, la sua popolarità è crollata ai minimi, si ritrova contestato dentro e fuori il partito laburista, già si parla di una sua sostituzione prima che il vantaggio dei conservatori si faccia incolmabile. Eppure il premier britannico Gordon Brown, screditato come pochi altri leader d’oltremanica, non ha esitato a prendere la testa dello schieramento trasversale che per mesi ha sostenuto il progetto di legge a favore della creazione a scopo di ricerca di embrioni ibridi uomo­animale, cavalcando una questione che divide l’opinione pubblica inglese assai più che il suo Parlamento (dove pure si è cementato un agguerrito fronte del no, sinora purtroppo minoritario). E ieri sera, infine, ha spuntato il via libera a una norma dal sapore altamente simbolico.
    Il provvedimento, passato per un voto favorevole alla Camera dei Lords e ieri a quella dei Comuni, modifica l’equivalente inglese della nostra legge 40 e apre la strada all’inaudito: i laboratori britannici vengono messi nelle condizioni di miscelare cellule riproduttive umane e bovine, abbattendo grazie al capriccio di una maggioranza parlamentare (336 contro 176, per la precisione) la barriera naturale tra l’essere umano e le specie animali. Per oltrepassare una frontiera insormontabile come quella che ha sempre impedito di ipotizzare seriamente la creazione delle cosiddette ‘chimere’ occorreva il propellente di una volontà umana determinata a produrre in laboratorio ciò che non esiste e non ha senso di essere generato, travestendo questa profanazione senza ritorno con argomenti ‘umanitari’. Gli stessi che un premier a corto di simpatie popolari ha usato a piene mani nell’articolo con il quale dalle colonne dell’Observer di domenica ha puntato sui sentimenti dei britannici: «Lasciate fare alla scienza – ha scritto in buona sostanza Brown –, vedrete che un giorno le staminali estratte dagli embrioni ibridi salveranno milioni di persone colpite da malattie oggi inguaribili» (come la fibrosi cistica, che affligge il suo terzo figlio).
    Un argomento che suona familiare, vero? È lo stesso che tre anni fa, proprio in questi giorni, il fronte contrario alla legge 40 rovesciava sugli italiani perché si sbarazzassero per via referendaria di norme ritenute retrograde solo perché pongono come architrave di una legge che parla di vita umana la tutela dell’embrione anziché il suo uso strumentale. La gente disse la sua con estrema chiarezza, dopo aver compreso i termini tanto netti quanto semplici della questione. E la sensazione è che anche agli inglesi – quattro su cinque, secondo un sondaggio di pochi giorni fa – piacerebbe capire qualcosa di più su ciò che i deputati hanno discusso, non fidandosi solo ciecamente di una scienza che senza portare alcuna prova chiede con arroganza senza precedenti di chiudere entrambi gli occhi davanti alle provette dove nascono entità simil-umane. A cosa possa realmente servire questo sfregio senza precedenti alla dignità dell’uomo, umiliato al ruolo di materiale da laboratorio ed equiparato a un quadrupede, nemmeno gli scienziati sono davvero in grado di dirlo, figuriamoci un primo ministro. Gli stessi ‘profeti delle chimere’ (come Stephen Minger, invitato mesi fa dai radicali a Roma, dove liberamente parlò alla Sapienza) non hanno nulla in mano. Zero, niente di niente. Eppure chiedono un sacrificio insostenibile. Persino i primi esperimenti autorizzati dall’Autorità inglese che vigila sulla ricerca nel settore hanno dato vita a embrioni sopravvissuti solo tre giorni, troppo poco per farci alcunché.
    Tutto questo mentre le staminali adulte inanellano un successo dietro l’altro e nei laboratori di mezzo mondo si lavora alle «cellule riprogrammate indotte», matrici inesauribili di staminali identiche a quelle embrionali, tratte dalla pelle senza sognarsi di intrecciare il nostro dna con quello di una mucca. E allora, mister Brown, perché vuole gli ibridi? Per assecondare l’industria biotech inglese che vuole spuntare brevetti prima che altri – in Spagna, in Corea, a Singapore… – facciano lo stesso? O per fare dell’Inghilterra la patria mondiale della scienza priva di limiti? Almeno, lo dica.

  21. Mefistofele / May 20 2008 5:19 PM

    dall’insero “èvita, ops….E’ vita di Avvenire”

    Fuoriporta (15 maggio 2008)
    Embrioni chimera, Londra ha fretta. Troppa

    di Elisabetta Del Soldato

    Sono momenti difficili per il premier britannico Gordon Brown. I sondaggi lo danno praticamente spacciato nel caso di un’eventuale ricorso alle urne per elezioni politiche; la gente sta perdendo sempre più fiducia in lui, e si dice addirittura che si sia rifugiato, per avere consiglio, dal suo vecchio amico-nemico Tony Blair.

    A minacciare ancora di più la sua posizione ci sono le pressioni che gli arrivano dal suo esecutivo, con alcuni membri che lo vorrebbero già vedere sostituito con il più giovane ministro degli Esteri David Miliband. E come se non bastasse, ora è accusato di voler spingere in avanti a tutti i costi un disegno di legge che solleva problematiche etiche e morali enormi. Uno studio di ComRes (Comment on Reproductive Ethics) diffuso ieri mostra che quasi otto britannici su dieci (il 77%) credono che il governo perderebbe in popolarità se decidesse di bruciare le tappe per quanto riguarda il controverso «Human Fertilisation and Embryology Bill» (il disegno di legge sulla fecondazione artificiale e la ricerca sugli embrioni, in discussione alla Camera dei Comuni), senza lasciare ai cittadini il tempo di esprimersi sulle questioni morali che il testo solleva.

    I tre emendamenti della legge che più hanno scatenato la ribellione riguardano tre possibilità cui si vuole aprire la porta: concedere ai ricercatori di creare embrioni chimerici uomo-animale; cancellare l’obbligo di presenza della figura del padre nei trattamenti di fecondazione artificiale; creare embrioni mirati alla cura di un fratellino o una sorellina malati. L’opposizione si è fatta sentire anche all’interno del governo, quando tre ministri hanno deciso di schierarsi contro il provvedimento, ottenendo però solo una libertà di voto «misurata», a condizione cioè che il progetto di legge alla fine sia approvato. Il rifiuto di un aggiramento delle problematiche etiche si è visto anche fuori dall’esecutivo, espresso da un folto schieramento di politici, scienziati, accademici e religiosi, esterreffati soprattutto dalla velocità con cui questa legge è stata promossa senza chiedere niente a nessuno, senza fare domande o offrire spiegazioni, senza tenere in alcun conto i suggerimenti che pure sono arrivati.

    Forse la pecca più grave di Gordon Brown, spiegava ieri Josephine Quintavalle dell’associazione pro-life Core, «è proprio quella della superficialità con cui ha trattato questo disegno di legge, approvandolo senza esitazioni e privandoci dei tempi e degli spazi per poterlo discutere, analizzare a fondo, potendone prendere in considerazione seriamente le implicazioni etiche e morali».

    Secondo il nuovo sondaggio di ComRes, la grande maggioranza dei sudditi di sua maestà vorrebbe che il governo concedesse più tempo al dibattito pubblico anziché far sì che il disegno legge compia il suo percorso in modo frettoloso e sbrigativo. «La gente è sempre più irritata – continua Quintavalle – dalla velocità con cui Gordon Brown fa correre questo controverso disegno legge senza ascoltare né i cittadini, né i suoi stessi parlamentari. Gli emendamenti proposti riguardano problemi, come quello degli embrioni creati usando materiale genetico umano e animale, che meritano un ampio dibattito. La gente vuole poterne parlare. Eppure Brown sembra determinato a negare al popolo e ai suoi stessi parlamentari qualsiasi opportunità di esprimersi che non sia stata rigidamente delimitata». E conclude: «Mi chiedo cosa penserà la gente della sua promessa di ascoltare, se andrà avanti così come intende fare, se permetterà ai parlamentari solo tre ore per discutere la questione e se concederà una sola opportunità di votare liberamente, andando di fatto contro ciò che l’opinione pubblica chiaramente vuole in larga maggioranza. Mi appello al premier affinché consideri questo sondaggio come un’opportunità per rassicurare la gente che lo sta ascoltando, dando ai parlamentari più tempo per dibattere e piena libertà di voto a ogni fase».

    La sensazione generale è quella che il governo abbia proceduto senza veramente consultare o informare il pubblico. La Quintavalle, così come molti oppositori del disegno di legge, sostengono infatti con determinazione che i cittadini hanno bisogno di capire i complessi contenuti degli emendamenti che vanno a modificare la legge esistente (molti non sanno neanche di cosa trattano) per approfondirne poi le implicazioni etiche. Ma il tempo sta scadendo. L’ultima parola sulla nuova legge sarà detta la prossima settimana con un altro voto alla Camera dei Comuni. Sarà in quel momento che i deputati dovranno esprimersi. Nel frattempo team di scienziati di Londra e Newcastle stanno andando avanti con i loro esperimenti grazie al via libera garantito dalla Human Fertilisation and Embryology Authority, creando embrioni ibridi. Possono essere fermati solo se la prossima settimana i deputati voteranno per vietare le chimere, intanto però approfittano dell’attesa. «Ma stanno agendo contro la legge – spiega la Quintavalle – perché la legge tuttora vigente non menziona neanche la possibilità di mescolare umani e animali. Perché poi questo accanimento a favore della creazione di ibridi quando la scienza ha già dimostrato di poterne fare a meno, usando metodi eticamente corretti come quello dei tessuti umani adulti, raggiungendo gli stessi scopi?».

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