Sunday, 24 August 2008

Potential Impact of Stem Cell Research (Part 2)

Right, so we have covered what stem cells basically are (Stem Cells 101), and I touched on their potential impact in the next post Potential Impact of Stem Cell Research Part 1. Now let's look at the more controversial issues of cloning. I think this is the area which is most misunderstood, and seems to cause most problems for many people.

There are two distinct subjects to cover:
a. Therapeutic Cloning.
b. Reproductive Cloning.

Therapeutic Cloning
This is where cloned tissue is used to "grow" replacement organs for people who have sustained damage to their organs (through disease, or injury, for example). It so happens that this month (August) is organ donors month. I would encourage everyone to consider signing up for organ donation. Discuss it with your family, as obviously your decision will effect them. But organ transplants are becoming more commonplace (as we know, the first heart transplant was performed in SA). Transplants are held back for 2 main reasons; the availability of organs, and also the fact that the human body tries to reject foreign tissue. To get around the second problem, the recipient has to be pumped full of very strong anti-rejection drugs (which also leaves the person with vastly weakened immune systems). This can often lead to complications, other infections and death. Our knowledge is increasing in this though. The concept of therapeutic cloning is to use (ideally stem cells derived from that person, from potentially umbilical cord cells, or from adult stem cells) tissue that has been grown from stem cells that have had the recipients own DNA introduced into them (by the use of Somatic Cell Nuclear Transfer - SCNT). This would negate the rejection problem. Recently, in Imperial College London, a heart valve was produced and transplanted into a patient. Because stem cells have the ability to grow into any cell, then it is hoped that almost any tissue or organ could be produced in this manner. The potential of this is huge, and could dramatically improve the survivability of people who are severely injured in car accidents, properly functioning pancreases may be grown for people with diabetes, brain tissue producing the right amount of dopamine for people with Parkinson's Disease, new kidneys for people in renal failure, eye tissue & retinas for people with different conditions causing blindness such as RP, the list is very long… Of course we have a long way to go, and it may well be that we have some more huge hurdles to overcome. The mass media has overplayed the timings (and ease) of this science. It is hugely complex, and the likely benefits are still some time away.

Reproductive Cloning
Reproductive cloning is where a completely genetically identical embryo is produced. Think Dolly the sheep (whose stuffed body can be viewed in the Museum of Scotland), or Booger the pitbull. Again, I feel that the mass media are at fault in badly reporting the issues around reproductive cloning, with visions of armies of identical Aryan peoples. The media has also falsely reported that human cloning has already happened in some countries, but a more detailed look at the evidence would suggest that this is very unlikely. Reproductive cloning is also fraught with complex problems (aside from the ethical considerations). There is also a complete misunderstanding about what a clone is. A clone is a genetically identical twin. But this would not mean that the clone would think exactly alike to the donor. But, as we know in the nature / nurture observations, genes are only part of the make up of any characteristics. Identical twins, that have been separated at birth, while still displaying obvious visual similarities, can often grow up to have completely different characters, molded by the environments in which they grew up in. Dolly would not have had the same thought processes as her donor animal. Very few people see any benefit of producing human (or indeed any animal) clones, as there is no increase in the genetic profile. There is the theoretical possibility of producing a reproductive clone with the sole purpose of harvesting donor organs, but there are obvious moral & ethical issues to this. But nevertheless, it is important that any discussion on ethics and morals around this subject must also consider this possibility.

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