Embryonic stem cells have the amazing potential to develop into many different types of cells.  A key goal in current embryonic research is to understand how this differentiation of embryonic stem cells is controlled and to learn how to direct their cellular development. Ultimately, this could lead to growing tissues or organs specifically for transplanting into humans.  Indeed in June this year, it was reported that this has been achieved for the cow, it is only a matter of time until this is developed for humans. 

The potential is fantastic. Imagine in the future, that you need an organ transplant and cannot find a donor.  You are told that the organ could be grown for you from an aborted embryo or from ‘spare’ embryos created for IVF treatment. Your life could be saved by an otherwise discarded material.  There are obvious ethical issues regarding abortion and the throwing away of embryos, but you need your transplant!  What would you do?

On careful consideration, this might not be the best way to get your transplant.  A major problem with organ transplants is not simply availability, but matching.  Wouldn’t an organ grown from any left-over embryo most likely be rejected by you?  Not if therapeutic cloning were used.  Therapeutic cloning proposes to create human embryos solely for the production of stem cells, rather than the creation of life (more ethical considerations).  If therapeutic cloning was used, the patient (i.e., you)  would be cloned to produce an embryo with identical DNA.  The stem cells would then be harvested and grown into the needed organ, which will then have no potential to be rejected, because the DNA would be yours.  It is easy to imagine that this technology could open the doors to creating baby clones.  However, UK law does not permit the growing of these embryos outside the body for more than 14 days, after which they are destroyed.  This is the case with surplus embryos left over after successful IVF treatment, another ethical issue. 

Perhaps you object to obtaining your organ in this manner.  Lets look at the alternatives.  A transplant from another human being is difficult to find and, unless it is your twin, it could cause rejection.  If it doesn’t cause rejection you could be taking anti-rejection drugs for the rest of your life, with the potential for very serious side effects. 

Xenotransplantation (taking an organ from another species) could be an alternative.  You may be able to obtain a pig organ that has been genetically modified to your specifications so as not to cause rejection.  Problems here include: i) the possibility of latent disease being transferred from the pig to the patient and ii) the questionable ability of a pig’s organ being able to function in exactly the same manner as a human one.

Perhaps you could get your organ from genetically engineered embryonic stem cells that have been created as a ‘one cell fits all’ line - modified so as not to trigger immune rejection in any transplant recipient.  Yes, you are still using embryonic stem cells, but these are from a cell line that could have been created and manipulated a long time ago. Embryos are no longer used in research, i.e., this was a one-time-only process.  A few embryos  were needed initially, but then the work would never or rarely need to be done again?  What are your ethics here?

Unlike research on embryonic stem cells, there are diminished or minor ethical concerns expressed by most individuals over the use of adult stem cells. However, critics have said that these are not as pliable as embryonic stem cells.  Therefore, it may be a) difficult to get adult stem cells to become other types of cells and b) difficult to maintain the adult stem cells in long term culture.

The adult material would need to come from you (the person needing the transplant) so as to avoid rejection.  Large sources of stem cells include the bone marrow and placenta.  However, if you needed an organ transplant it is doubtful whether your clinician would allow you to have a bone marrow transplant, a serious operation that can be debilitating, if only transiently.  The placenta required would be the one that was created when you were created, this was most likely discarded when you were born.   However, if we are talking about the future, it is possible that your parents had this stored for you in a private bank waiting for an instance such as this to occur, an expensive business and yet another ethical issue*.  You might ask why this isn’t done from birth for every citizen?  A simple answer would be that the cost would be phenomenal and could not be justified considering the very small proportion of placentas that would be used ultimately.

Back in the present day, none of these approaches are possible, all are being explored. 

Whilst stem cell research may show extraordinary promise, there is much to be done before we can realise these innovations. Basic research is required to understand the cellular events that lead to cell specialisation in the human, so that human stem cells can be told to become whatever tissue or organ is required.  Funding is required for this basic research and technological advances need to be made before these discoveries can be incorporated into clinical practice.   However, research is not necessarily led by technology, the funds given or the ability of our great thinkers, but by the ethical standards that society lives by.  It was once against the law to examine dead bodies to help our understanding of ourselves.  How far are you willing to go for your transplant?

 
Shara.B.A. Cohen  BSc (Hons), PhD, MIBiol, CBiol, MRCPath, FWIF