Stem cell

Many of us will have rejoiced at the award of a Nobel Prize to Sir John Gurdon (shared with Shinya Yamanaka) for his work leading to the therapeutic use of human stem cells. It’s not every day that a pupil whose scientific ambitions were described as quite ridiculous by his teacher can prove the prophecy magnificently wrong. He challenged the dogma that the specialised cell is irreversibly committed to its fate and demonstrated his claim by producing a tadpole within a frog’s egg, using a transfer of nuclear DNA.

That was in 1962. More than 40 years later the question of whether mature cells could be re-programmed back to pluripotent stem cells (immature cells that are able to develop into any of the 220 cell types in the body) was answered by Yamanaka in 2006, through the introduction into the cell of a few specific genes.

Apart from the promise of a far better understanding of the relationship between cells and disease, and the development of potential cures, we note that these discoveries might make it unnecessary to continue with embryonic stem-cell research, with its corresponding ethical problems.

In looking at this issue we should first be aware that this whole field is really very new. Currently there are no less than 477 studies, reported internationally, involving stem-cell research. The knowledge bank changes literally from day to day. Nevertheless. we can begin to make sense of it all by looking at the broad principles.

One of the marvels of genetics is that the identical stem cells of an embryo are programmed so that they can develop into all the specialised cells of the human body. Gurdon came to believe that each cell had the potential to turn back this development so that it was restored to its original state. The prospect was a kind of Holy Grail through which damaged and diseased human organs could be re-grown. In later years it came to be thought that the obvious, and immediate, source of such pluripotent cells was the embryo, using either a “spare” embryo from in vitro fertilisation or one bred for the purpose. Unsurprisingly it was pointed out that the dignity and rights of human beings from conception onwards were being violated. But those scientists, for whom the end justified the means, continued notwithstanding. In practice it appears that few, if any, cures have resulted from this research. GeronCorp, the world’s leading embryo research company, announced, in November 2011, that it was closing down its stem cell programme and concentrating elsewhere.

By contrast, adult stem-cell research has made considerable progress, for example in the treatment of heart damage. But here, too, we are still making infant steps. These stem cells offer the possibility of the re-building of organs and the treatment of many diseases and disabilities such as Parkinson’s disease, amyotrophic lateral sclerosis, spinal cord injury, burns, heart disease, diabetes, and arthritis. They have been known for a long time, and are to be discovered in a large number of different tissues. They appear to act as a kind of reserve, coming into action when the tissue concerned requires healing. They can be collected and artificially infused into the right tissue or organ to bring about growth. Their use in organs other than their native tissue appears to be very limited, and in order to obtain “universal” stem cells, re-programming is required. This is where we came in.

Enter Shinya Yamanaka. He experimented by using retroviruses (a type of virus which can transfer genetic code to its host) to transcribe different re-programming genes into the DNA of an ordinary adult cell – until he found the four which did the trick. The induced pluripotent stem (iPS) cell was ready to be returned to its host. There was, however, a problem. The retrovirus itself proved capable of causing cancerous changes, and so other methods of transcription have had to be used. Work in refining and developing technologies continues.

The advantages of iPS cells are considerable. Ordinary body cells provide the source material and, when that source can be the patient awaiting treatment, rejection by the immune system is unlikely. Not only may they have major therapeutic and reconstructive purposes, they provide material on which drugs intended for human use can be tested and the nature of diseases better understood. There is even experimental work being done on using the technique to alter rogue genes.

Yamanaka was able to report that human iPS cells were identical to stem cells in all relevant ways. But life is not so simple. As other laboratories reproduced and extended his work, various hitches have materialised. None of these have proved game-changers, but they remind us that we are talking about years, rather than months, of painstaking work before we will know and really benefit from this development.

Does the advent of iPS cells spell the end of that ugly embryonic stem-cell work, which involves the death of so many young? I suspect not – at any rate for the time being. It can always be argued that more research could produce unique results or that, if the iPS cell programme should stumble for some unforeseen reason, it would be waiting in the wings. In 2009, well after the potential of iPS cells was realised, President Obama reversed Bush’s ban on federal research money for embryonic stem cells. But, in the long run, the money, public or commercial, tends to follow the better bet. Meanwhile, ethicists may like to turn their minds to the theoretical prospect of conceiving humans with sperm and ova developed from skin cells.

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About Quentin

Science Editor, Catholic Herald. Portrait © Jacqueline Alma
This entry was posted in Bio-ethics, Catholic Herald columns, Moral judgment and tagged , , , . Bookmark the permalink.

7 Responses to Stem cell

  1. Peter D. Wilson says:

    On your last point, it it’s possible, someone will insist on doing it, ethically or not.

  2. tim says:

    I don’t think work on human embryonic stem cells (Hescs) will end any time soon. The problem is that most scientists simply don’t see there is a problem. They buy the ‘bundle of cells’ label for embryos – and will ask what the difference is between doing research on embryos and similar research on human ova and sperm. And mostly they use cell lines generated from destruction of human embryos (rather than destroying them themselves) – and argue that since the embryo involved is now past saving, what can be wrong in some good now coming out of its loss? And of course valuable knowhow and commercial property has been built up, and people are reluctant to change from what they know. The best chance may be that the area will be heavily regulated, which puts people off (we get this with plant GM). Quentin, when you say ‘years rather than months’ I think you’re too optimistic – I would say ‘decades rather than years’. It’s tricky stuff, technically as well as ethically.

  3. Brendan O' Leary. says:

    In our materialistic rational world it is difficult to disagree with Peter and Tims’ coclusions. What the Yamanaka / Gurdon approach has shown, is that working from the basic moral principle that all human life is sacred ( special ) – as defined by The Creator – whether one realises it or not, major breakthroughs in the scientific field can be achieved by using the material that He provides for us, in an ethical way based on a universal law of nature which stems from The Creator. This vital moral/ethical stance is self-evident in the failiure of research in the areas where science has strayed as Quentin says, “.. from the boundary of God’s privilege, which we may not overstep. ”
    Therefore, embryonic stem cell research has proved of little or no value, while generally from its inception, non-embryonic stem cell research is proving its worth. Ironically, in a , reverse procedue, it is interesting to note that the changing of mature embryonic stem cells to its pluripotent form has not proved as successful as might have been expected. I am tempted to remind myself of the basic principle ……” it is wrong to do evil that good may come of it.” As Quentin reminds us, ” .. the identical stem-cells of an embryo are programmed so that they can develop into all the specialised cells of the human body.”
    It seems that we, made in ” His image and likeness”, are being shown in genetic science how He brought this likeness to perfection in us – where science and religion meet, that is another marvel which tells me that the two are mutually compatible in their different ways of fulfilling the common good. One can only hope and pray that the singular sexual / procreative act between humans willed by God for us to muliply, will continue to be respected and other forms of human reproduction be rejected on this theological/philosophical basis.

  4. Andrew Brown says:

    The best chance may be that the area will be heavily regulated, which puts people off (we get this with plant GM). Quentin, when you say ‘years rather than months’ I think you’re too optimistic – I would say ‘decades rather than years’. It’s tricky stuff, technically as well as ethically.

  5. Vincent says:

    I wonder if there is a danger of underestimating where these lines of research may take us. While the potential benefits which Quentin outlines are positive we must accept from experience that scientists will follow any promising line as far as it will go. While some countries like our own may be persuaded to exercise statutory control there are plenty of areas where this will not be so.

    While we may jib at the idea of conceiving human beings through the use of skin cells, this may be a small step in comparison to complete mastery of the cell and its DNA content. While we can never create from scratch since we have to use existing cell material we could well be in a position to breed what humans and with what characteristics seem most useful to us. Books like 1984 and Brave New World present a frightening picture, but they are mild compared with what may really occur – if not in this century, surely in the next.

  6. Singalong says:

    Research and work with human cells is so scientific and complicated that it is difficult for a lay person not to be “blinded with science” especially when the prospect of cures or prevention for serious and degenerative illnesses, and alleviation of chronic pain and disability is held out as the prize. Inoculation against German measles for girls, before they might become mothers, was in part at least derived from human embryos some years ago, I don`t know if it is still, and we found it very hard to insist on the alternative which was available. The surgery concerned agreed very reluctantly, and thought we were being unnecessarily scrupulous. I cannot remember if the alternative was actually stem cells.

    The question of the possibility of human reproduction from skin cells would indeed be even more of a minefield than the various fertility processes already being used now. Can it be in accordance with God`s will for any of these methods to be used? One major consideration is the need we all have to know our genetic inheritance, which is becoming even more difficult than it can sometimes be in traditional situations, when adoption or infidelity can complicate or falsify parentage.

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