The real issue behind egg fusion techniques
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B i o N e w s 056
Week 25/4/2000 - 1/5/2000
C O N T E N T S:
1 C O M M E N T A R Y
* The real issue behind egg fusion techniques
2 N E W S D I G E S T
* Gene therapy success
* New egg fusion technique
* Cloned cows young for their age
* Human genetic diversity project at risk
* New study of multiple births families
3 R E C O M M E N D S
* Television, conferences and further reading
1 C O M M E N T A R Y
* THE REAL ISSUE BEHIND EGG FUSION TECHNIQUES:
A new reproductive technology is on the horizon. Egg fusion, described in
this week's BioNews, could have a significant impact on the lives of many
women who cannot currently conceive naturally. Apart from the women with
fertility problems who might benefit from this technique, egg fusion could
also be of use to women who are at risk of passing on a mitochondrial disease
to their children.
But, rather than celebrating the fact that these people might soon be
able to use a technology that would allow them to have a genetically related
child, the British press got all excited about egg fusion for an altogether
different reason. They worked out that the procedure isn't all that different
The similarity of egg fusion to reproductive cloning may be an issue
worth mentioning, but there is another, much more immediate issue that was
barely mentioned in the media commentary. It is that the French, Spanish and
Italian researchers who worked on the egg fusion technique are prohibited
from testing it any further because of restrictions in the laws of those
countries. This means that a potentially viable reproductive technology will
be slow to come to clinical practice and a whole host of infertile women or
women at risk of passing on a mitochondrial disease to their children will
In Britain, the creation of embryos for research purposes is not
prohibited by law, but we don't have a proud tradition of charging ahead with
new techniques. ICSI, egg freezing, ICSI using immature sperm and now
probably egg fusion: these are all techniques that the HFEA has been
reluctant to license in the UK. Yet, research that involves the fertilisation
of human eggs in the laboratory (and thus the creation of a human embryo) is
There are three options available when it comes to developing a new
technology that intervenes before or during fertilisation. The first is to
not do the research and not make the technique available to anyone. The
second is to forego embryo research and introduce the technique directly into
clinical practice. And the third is to carry out research, making sure that
fertilisation and subsequent development is normal and then introducing the
technique into clinical practice.
Which would you prefer? A technique which is tested on embryos, a
technique which is tested on women or no technique at all?
- Juliet Tizzard, director, Progress Educational Trust
2 N E W S D I G E S T
* GENE THERAPY SUCCESS:
A team of French scientists at the Necker Hospital, Paris, has successfully
used gene therapy to treat two babies born with a life-threatening genetic
condition that affects the immune system. Usually, babies with severe
combined immune deficiency (SCID) X1 have to live in sterile 'bubbles' to
avoid any infections. But following the treatment, the babies are now living
normal lives at home, the researchers reported in last week's issue of
Science. A third baby is making similar progress after four months of the
Children with SCID X1 have no working version of a gene that controls the
development of the immune system. To carry out the gene therapy treatment,
the researchers first harvested bone marrow from the patients. They then
isolated blood stem cells from the bone marrow, which they infected with a
virus carrying a replacement gene. After three days of repeated gene
transfers, the cells were transplanted back into the patients, with no prior
drug treatment. 'It was important to show success in the absence of any
chemotherapy' said Dr Alain Fischer, co-author of the study.
After just fifteen days, the scientists were able to detect new immune
cells carrying the replacement gene in the patients' blood. The two baby
boys, aged eight and eleven months, now have near-normal immune cell levels
and have responded normally to routine polio, diphtheria and tetanus
Fischer believes the key to their success lies 'not in the technique, but
in the disease itself'. Immune cells with the replacement gene seem to
multiply rapidly, overwhelming cells without a working gene. 'This means that
even a poorly efficient gene therapy treatment - one that only introduces a
few cells with the right gene - may work as a treatment' he said.
- The Daily Telegraph 28/4/2000 'Gene trial frees babies from sterile
- The Daily Telegraph:
- BBC News Online 27/4/2000 'Gene therapy frees 'bubble babies''
- BBC News Online:
- ScienceDaily Magazine 1/5/2000 'Gene therapy frees two children from
- ScienceDaily Magazine:
- The Guardian 28/4/2000 'Immune cells gene therapy saves babies'
* NEW EGG FUSION TECHNIQUE:
A team of French, Spanish and Italian researchers has developed a new
technique that may allow some infertile women to have their own genetic
child. The new method, reported by the scientists in this month's issue of
Human Reproduction, involves replacing the genetic information of a donor egg
with that of the patient's egg.
The technique could help those women whose embryos repeatedly fail to
develop because of problems with the egg cell cytoplasm, which surrounds the
nucleus. Although this problem affects less than ten per cent of women
attending fertility clinics, they can currently only be treated using donated
eggs. But by transferring the nucleus of one of her eggs to a donor egg with
its nucleus removed, such a woman may be able to have a child who is almost
entirely genetically her own (with the exception of the 37 genes present in
The team has successfully managed to transfer egg nuclei to donor eggs
using two approaches. One method involves using a chemical 'glue' called
phytohaemagglutin, and the other involves a delicate microscopic manipulation
similar to that used for intracytoplasmic sperm injection (ICSI). 'Because
ICSI will probably be the best way of fertilising the reconstructed eggs the
mechanical method we've developed will have the advantage of simultaneously
fusing the eggs and introducing the sperm in a single, relatively simple
action' said Dr Jan Tesarik, head of the team.
So far, the scientists have not attempted to fertilise any of the
reconstructed eggs, because the formation of embryos for research purposes is
banned in France and Spain and strictly regulated in Italy. But Dr Tesarik
believes they are now ready to try and develop treatment for women who might
benefit from the technique.
A spokesman for the UK's Human Fertilisation and Embryology Authority
said that any UK clinic wishing to offer the technique could apply for a
licence to create embryos using the method, but that doctors would have to
satisfy the authority that the technique was safe before a licence could be
granted. A spokesman for the fertility group Issue said the technique may
assist thousands of couples to have their own baby.
- The BBC News Online 26/4/2000 'Egg breakthrough hailed by scientists '
- The BBC News Online:
- The Guardian 27/4/2000 'New fertility treatment hope for childless'
- The Daily Telegraph 27/4/2000 'Donor eggs to carry mother's own genes'
- The Daily Mail 27/4/2000 ''Breakthrough' that gives IVF babies their
* CLONED COWS YOUNG FOR THEIR AGE:
Six cloned calves have cells that appear younger than their biological age, a
US biotech firm reported in the current issue of Science. A team working at
Advanced Cell Technologies (ACT) found that cells taken from the cows and
grown in the laboratory have a lifespan increased by around 50 per cent.
The results surprised the researchers, because the cows were cloned using
cultured calf embryo cells that were nearing the end of their lifespan. 'The
old cells were not merely returned to a youthful state. They were actually
given a longer lifespan than those from normal animals' said Dr Robert Lanza,
who carried out the research. The scientists also found that a gene (EPC-1)
whose activity normally declines with age was five times more active than
normal in the cloned cells.
A cell can usually only multiply a certain number of times before it
dies. Each time a cell divides, the ends of its chromosomes, called
telomeres, become shorter. The telomeres of the cells from the cloned calves
are longer than those of normal cows of the same age. When grown in the
laboratory, cells from a normal newborn calf divide up to 60 times, but the
cloned cells can divide up to 90 times.
The team thinks its results may be down to the type of cell used to
create the clones - a skin cell, or fibroblast. When Dolly the cloned sheep
was born, her cells appeared to be the same age as the mammary cell of the
six year-old ewe from which she was cloned. Another factor may be the stage
in the life cycle of the donor cells. The cells used to create the calves
were still growing and multiplying, whereas those used to clone Dolly were
in a resting stage.
Although a long cell-life may not mean the animals live longer than
normal cows, the company says its work has important implications for human
therapeutic cloning - the use of cloned early embryo cells to replace damaged
or diseased body tissues. The ability to create a supply of youthful cloned
cells may get around the potential problem of growing enough cells in the
laboratory before they become too old to use for treating patients. 'It's the
first day in a new era in treating age-related disease' claimed Dr Michael
West, president of ACT.
- The Daily Telegraph 28/4/2000 'Scientists turn back the clock'
- The Daily Telegraph:
- BBC News Online 27/4/2000 'Cloning cattle reverses ageing'
- BBC News Online:
- The Guardian 28/4/2000 'Cloned calves offer clues to 'fountain of youth'
- The Sunday Times 30/4/2000 'Cloned cells can mend human organs'
- The Sunday Times:
* HUMAN GENETIC DIVERSITY PROJECT AT RISK:
The Human Genome Diversity Project (HGDP), a scheme to collect and analyse
DNA samples representing the world's ethnic diversity, is fighting for its
life, according to a news report in last week's Nature.
A combination of political and public controversy has turned the
ambitious international project into a set of DNA collection projects, funded
from a variety of sources. Without further support, the DNA database and
repository originally planned by the project's organisers seem unlikely to go
Some countries, such as New Guinea, are demanding a fee for every sample
taken by researchers. Others, such as India, have completely forbidden the
export of DNA. The HGDP may also have lost funding to projects with
overlapping aims, such as the SNP (single nucleotide polymorphism)
consortium, which aims to identify genetic differences associated with
disease or drug responses.
'Our lack of funding is a huge issue' says Henry Greely, a spokesman for
the HGDP. But he added that rumours that the HGDP has died, or is in a
comatose state, were exaggerated. Lap-Chee-Tsui, president of the Human
Genome Organisation (HUGO), says that the programme doesn't have clearly
defined goals and questions. But former HUGO president Walter Bodmer thinks
that support for the HGDP project will grow, as more scientists become aware
of the uses of data on genetic variation.
- Nature 27/5/2000 'Genetic diversity project fights for its life'
* NEW STUDY OF MULTIPLE BIRTHS FAMILIES:
A new study of parents who have multiple births following fertility treatment
has found that they are more at risk of physical and emotional problems than
parents who have a single baby. The report, published in this month's issue
of Human Fertility, looked at 54 families which had children following
treatment using assisted reproduction techniques.
The study found that mothers of twins and triplets may become socially
isolated, because they find it difficult to get their babies ready to leave
the house and too daunting to use public transport. But after years of
longing for children, many feel too guilty and ashamed to admit they are
having problems coping, says Dr Alexina McWhinnie, author of the study.
Over the past 20 years, the incidence of twins has nearly doubled, and
that of triplets nearly quadrupled. Last year, the Royal College of
Obstetricians and Gynaecologists recommended that a maximum of two embryos be
transferred into women receiving fertility treatment, to reduce the numbers
of multiple births.
'If more than two embryos are transferred then clinics should consider
targeting those families most at risk in relation to social factors' said Dr
McWhinnie. She added that these families should have adequate and immediate
help once they leave hospital, and continuing support over a considerable
- The Independent 1/5/2000 'Multiple births 'put great stress on couples''
- The Independent:
3 R E C O M M E N D S
* TELEVISION, CONFERENCES AND FURTHER READING:
'The Fifth World Congress of Bioethics' / Imperial College, London, UK /
21-24 September 2000
Organised by the International Association of Bioethics, this four day
conference will focus on the relevance of bioethics and healthcare ethics to
professional practice, policy and law. Costs £250 for IAB members and £270
for non-members. For further details and on-line registration visit the
'Defining Features: Scientific and Medical Portraits / The National Portrait
Gallery, London, UK
An exhibition of portraits of scientific and medical men and women, including
Marie Curie, Edward Jenner and John Hunter. Free, in the Studio Gallery until
'Genetic testing and insurance' / The Lancet / 29 April 2000
A feature article outlines the view that fears about genetic discrimination
by insurers may be unfounded, and that legislation in some countries brought
in to register social disapproval may have caused patients and geneticists
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B i o N e w s
Copyright Progress Educational Trust 2000
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Progress Educational Trust
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