Human Embryonic Stem Cells Developed From 4-cell Embryo; World First May 
Lessen Ethical Concerns
ScienceDaily (July 9, 2008) -   For the first time in the world scientists 
have succeeded in developing human embryonic stem cells (hESCs) from a 
single cell, or blastomere, of a 4-cell stage embryo, the 24th annual 
conference of the European Society of Human Reproduction and Embryology 
heard today (Wednesday 9 July). Dr. Hilde Van de Velde, from the Vrije 
Universiteit Brussel (VUB), Brussels, Belgium, said that their research 
meant that it might be possible in the future to produce hESC lines at an 
earlier stage without destroying the embryo.
Blastomeres are formed in the very early stages of embryonic development. 
About 24 hours after fertilisation the egg divides into two cells. Division 
into four cells occurs after 48 hours. After 96 hours, at the morula stage, 
the fertilized egg has divided four to five times. During this time the size 
of the embryo does not increase, so the cells become smaller and smaller and 
they are strongly attached to each other which makes them more difficult to 
manipulate. At this early stage important decisions are taken: inner cells 
will become the foetus (including germ cells) and outer cells will become 
trophoblast (the outermost layer of the embryo that attaches to the wall of 
the uterus and serves as a nutritive pathway). There was, until now, 
uncertainty about which stage of early development the blastomeres ceased to 
be totipotent, i.e. able to develop into all cell types of the body.
Worldwide, the majority of established hESC lines have been derived from the 
inner cells at the blastocyst stage; these are said to be pluripotent. 
"Previously, scientists have been able to derive hESC lines at the 8-cell 
stage," said Dr. Van de Velde, "but success rates were variable and it was 
necessary to culture them by mixing with established hESC lines. We have 
been able to derive hESCs at an earlier stage of embryonic development, and 
without the need for co-culture with established hESC lines. Now we have 
derived a second hESC from one cell of a 4-cell stage embryo. Given the 
complex nature of earlier attempts, we were pleased that we could develop a 
technique that seemed simple and was also reproducible."
The scientists used mature eggs donated by couples being treated at the 
University's IVF centre. Embryos were obtained after ICSI using sperm from a 
consenting donor. Three, good quality 4-cell stage embryos were split into 
12 single blastomeres and allowed to grow in vitro to produce twelve morulas 
that were cultured in the conventional way for hESC derivation. From these 
twelve, one resulted in a stable hESC line. The scientists concluded that at 
least one cell was pluripotent.
These new data confirm their recent report that at the 4-cell stage the 
cells are equal and totipotent. "Now we will try to derive four hESC lines 
from the same embryo in order to compare the potency capacity of all four 
cells," said Dr. Van de Velde.
The work could have major ramifications for preimplantation genetic 
diagnosis (PGD), by enabling the biopsy of one cell from a 4-cell stage 
embryo, allowing the remaining three cells to develop into a blastocyst 
(five day embryo) which could be transferred into the uterus and develop 
into a healthy baby. "Currently, PGD is performed at the 8-cell stage, when 
one or two cells are removed; others have derived stable hESC lines at this 
stage but with low efficiency. If hESC derivation at the 4-cell stage turns 
out to be more efficient then at the 8-cell stage, we might consider to 
change our PGD policy in cases where we perform human leukocyte antigen 
(HLA) typing," said Dr. Van de Velde.
HLA molecules play an important role in the immune system by ensuring that 
our bodies recognise their own cells as their own. By being able to select 
an HLA-identical embryo, the cord blood of the 'saviour siblings' could help 
cure an older brother or sister suffering from a genetic disease affecting 
the production and/or function of hematopoietic (blood producing) stem 
cells. "We could also combine the pregnancy of an HLA-matched healthy baby 
with the derivation of a personal hESC line that could be used to generate 
in vitro hematopoietic stem cells as an additional source of hematopietic 
stem cells," she said.
"We need to determine whether the removal of one cell at the 4-cell stage 
impairs the capacity of the embryo to develop into a healthy child in 
comparison with the removal of one/two cells at the 8-cell stage. We 
understand that some people may have ethical concerns about the production 
of hESCs," said Dr. Van de Velde, "but we already know from cryopreserved 
embryos that the loss of one cell from a 4-cell stage embryo does not affect 
its capacity to implant in the womb. We believe that by making it possible 
to intervene at an earlier stage, and without destruction of the embryo, 
these ethical concerns will be diminished."
In fact, opinion among the public is very much in favour of stem cell 
research, another researcher told the conference. Ms Jaclyn Friedman, a 
clinical embryologist at Reproductive Biology Associates, Atlanta, Georgia, 
USA, undertook an on-line survey looking at attitudes towards IVF around the 
world. Two questions related specifically to human embryonic stem cell 
research and use in therapy.
"This is the first time an on-line questionnaire has been used to establish 
a cross-sectional view of ethical opinion in the global community," said Ms. 
Friedman. "Because stem cell research is increasingly important, we felt 
that we needed to gauge opinion among members of the public, as well as IVF 
patients, doctors and scientists working in the field."
The researchers analysed the following two questions:
"I believe that it is morally wrong to use embryonic stem cells for 
research"
and
"I believe that it is morally wrong to use embryonic stem cells for medical 
treatment."
573 people responded to these questions. The researchers found that 47.1% 
strongly disagreed with the viewpoint posed in question 1, whereas only 4.5% 
strongly agreed. 4.1% agreed, 10% were neutral, and 31.2% disagreed, meaning 
that in total 78.3% of respondents disagreed with the view that it is wrong 
to use hESCs in research.
For the second question, the results were broadly similar, although fewer 
people (3.1%) felt that it was morally wrong to use ESCs in medical 
treatment than in research. "We found no difference between male and female 
attitudes towards using hESCs for research, but when it came to medical 
treatment, men showed significantly more support than women. "We found no 
significant differences when we looked at particular age groups, but a 
higher level education of respondents correlated with greater support for 
the use of hESCs, both in research and medical treatment. There were no 
important differences among regions of the world.
"We hope that this questionnaire might act as a pilot study for something 
much larger and more representative of the views of the international 
community. But even with our existing numbers, we found enough difference 
between the views of people working in the field, the general public, and 
patients, to know that the results have statistical significance. Our study 
shows that public, patient, and scientific opinion is very much in favour of 
both stem cell research and the therapeutic use of stem cells in medical 
treatment. This is different from the perceived equal distribution for and 
against hESC use reported in the news media," she said.

Adapted from materials provided by European Society for Human Reproduction 
and Embryology, via EurekAlert!, a service of AAAS.

Rayilyn Brown
Director AZNPF
Arizona Chapter National Parkinson Foundation
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