The real value of embryonic stem cells?
Several controversies surround the use of human embryonic stem cells: Is it ethical to use them? Will embryonic stem cells ever be used to treat human diseases? Why not use adult stem cells instead? The focus of the media and the public has almost exclusively been on these issues but the value of embryonic stem cells, to this point in time, lies elsewhere.
As with many important scientific discoveries, embryonic stem (ES) cells came onto the scene long before the media and most of the rest of us became intensely interested in the subject. The first articles on the isolation of mouse ES cells were published in 19811 immediately heralding the possibility of isolating ES cells from other mammals. During the mid- to late-nineties, this possibility was realised, with the isolation of ES cells from various species including rabbit, pig, cow, and primates (monkey and marmoset), culminating with the publication in 1998 of two articles on the isolation of human ES cells2.
<>The value of ES cells can be
understood quite well by delving back to their origins in the early eighties.
Since that time, these cells have given us a wealth of information of how
mammalian embryos, including human babies, develop in the womb and how
development continues following birth. Just as importantly, research on these
cells has been providing us with what happens when foetal development goes
wrong, either because of a genetic defect or one that is imposed, for example,
by a chemical or drug. The real value of over two decades of ES-cell research
currently lies with these advances but there has been relatively little
‘external’ acclaim or general interest. This is a pity, since this basic
scientific endeavour has played positively into a wide range of fields of interest
to all of us, including human and animal toxicology, assisted human
reproduction, livestock breeding, and the molecular basis of disease.
<> Instead, as we know, interest and
debate has centred largely on the ethics and morals of using human ES cells to
treat, potentially, a range of human diseases, many of which are virtually
intractable with respect to a cure. While some extol the virtues of pursuing
the science, others want a line to be drawn in the sand. Debate has frequently
become obscured when, for example, a scientist with little training in ethics
ventures into the morals of the issue, and equally, when ethicists begin to
pick apart the quality of the science. These debates will, and must, rage on
but it interesting that two things in particular seem to be lost to most
debates on the issue: (i) the value of research to this point in time, and (ii)
the likelihood that the use of stem cells of any type to treat most if not
all these diseases remains, for a variety of reasons, a distant possibility.
<> No doubt, your own views will
come thick and fast. In future articles, I will briefly explore some of these
2 JA Thomson et al. (1998) Science 282, 1145; Shamblott et al. (1998) Proceedings of the National Academy of Sciences USA 95, 13726.