|Chief Medical Officer’s Expert Group on Cloning (CEGC)|
The Royal Society of Edinburgh is pleased to respond to the Department of Health’s consultation on the Chief Medical Officer’s Expert Group on Cloning. The RSE is Scotland’s premier Learned Society, comprising Fellows elected on the basis of their distinction, from the full range of academic disciplines, and from industry, commerce and the professions. This response has been compiled with the assistance of a number of Fellows with experience in this area.
The paragraphs below relate to the questions posed in the covering memorandum 'Expert Advisory Group on Therapeutic Cloning in Humans" dated 2 September 1999.
Current research areas on therapeutic cloning which are the most important
There are three main areas:
Cloning animals by nuclear transfer. This is developing in a number of species, including ruminants, pigs and mice. The range of species studied should be widened as it could well be that advances are initially more easily made in one species which, with further work and more detailed experimentation, can be applied more widely to other species, including man.
Pluripotent Stem Cells (PSCs). Mouse PSCs (or embryonic cells) are routinely used in many laboratories to introduce precise genetic change into the germline. When allowed to differentiate in vivo or in vitro they are able to form many of the adult cell types, and they are useful models for early development studies, such as researching the pluripotential state and as a means of understanding the mechanisms of differentiation of specific cell types, such as neurones and blood cells.
Re-programming. Nuclei from differentiated adult cells can be re-programmed into other pathways of development. This has great potential in human medicine because the nuclei from cells of an individual could be re-programmed to make, for example, heart muscle or neuronal cells which, being "autologous", would not suffer from immune rejection. At present, re-programming adult nucleiis solely by nuclear transfer into an oocyte which is not ideal. More research into the re-programming mechanism would enable the benefits to be obtained without recourse to oocytes and thus remove not only a logistic constraint but also lessen the ethical problems inherent in working with oocytes as the starting point.
Areas of human health in which therapeutic cloning is most likely to provide benefits
Possibility of replicating animal work to humans
Technical problems which may arise
There could be concerns as to the effects of in vitro culture on the propensity of such cells to undergo malignant transformation, either by mutation or by epigenetic changes. Governmentally supervised regulatory controls will be required to enable these cells to be clinically used, on the same principles that have already been established for evaluating new medicines. It should be noted that autologous transplants would be advantageous because immuno-supression will not be required.
Alternatives to achieve the same ends
However, it should be pointed out that under the 1990 HEFA Act, research with embryos is allowed up to the 14th day in order to overcome problems of human infertility, so it does not seem logical to impose tougher restrictions on work aimed at combating life-threatening diseases.
Until such time as alternatives to the use of oocytes are available, it may be necessary to carry out the transfer of a nucleus into a human embryo which was not foreseen in the original Act. Firstly, as a means of generating PSCs from a defined individual, for example if tissues for autologous transplantation are required, and secondly to allow a better understanding of how re-programming works in humans. It should be emphasised, however, that the eventual object of all this work is to carry out re-programming without recourse to the oocyte, and so in the long run this will reduce or eliminate the requirement for working on the most ethically sensitive of all human cells.
Consequences for health care provision
Further information is available from the Research Officer, Dr Marc Rands