Memorandum 22
Submission from the Scottish Stem Cell
Network (SSCN)
Thank you for inviting submissions of evidence
to your inquiry into the Government's proposals for the regulation
of animal/human hybrid and chimera embryos for research purposes.
The Scottish Stem Cell Network is mindful of the ethical tensions
in this field and would like to submit the following points for
your consideration.
1. Embryo stem cells obtained from blastocysts
produced by somatic cell nuclear transfer could help to advance
regenerative medicine in three ways: (i) through the creation
of cellular therapies immunologically matched to the patient,
(ii) through advancing understanding of nuclear re-programming
which could facilitate the use of adult tissue stem cells as cellular
therapies, (iii) through creating opportunities to study inherited
human diseases not available in other ways.
2. We believe that the production of bespoke
immunologically matched cellular therapies through cell nuclear
transfer is unlikely at present, particularly due to the shortage
of human ova and the inefficiency of both the cell nuclear transfer
and embryo stem cell derivation processes. Use of animal ova could
help to address some of these issues in the longer term.
3. Autologous tissue stem cells (ie procured
from the patient him/herself) could provide an immune compatible
source of stem cells for cellular therapies, but at present the
extent to which they can be directed to self-renew or alter their
differentiation commitment is unclear. Cell nuclear reprogramming
may improve our understanding of these processes and facilitate
this path to cellular therapy.
4. Many diseases have an inherited component
including Motor Neuron Disease and some other neurodegenerative
disease (such as Parkinson's disease, Alzheimer's disease) some
cancers, and some causes of sudden heart failure (cardiomyopathy).
The genetic mutations which predispose to these diseases have
been identified in only a minority of cases. Creation of embryo
stem cell lines with the genetic information from a patient suffering
from such a disease with subsequent differentiation of relevant
cell types may allow comparative studies with cells from a person
who does not have the disease. The aim of the research would be
to understand better the early stages of disease development and
identify potential drugs able to prevent or mitigate development
of the disease.
5. At present the only embryo cell line
established from a cloned human embryo was produced after transfer
of a human nucleus into a rabbit unfertilised egg (in China).
There are currently no embryo cell lines after transfer into human
eggs and it is not certain that this will prove possible.
6. There are a variety of limitations surrounding
the use of human eggs: there is an overall shortage of good quality
human eggs; donation involves the woman undergoing minor surgery
and usually hormone stimulation, both of which cause discomfort
and carry a minor risk; some women might be willing to donate
the eggs for use by other infertile couples and there is an unmet
need for these.
We feel that in these circumstances it would
be beneficial to be able to use eggs from rabbits and other animals
to allow these avenues of research to progress in a timely manner.
Thank you again for the invitation to contribute
to this consultation.
January 2007
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