Two research groups in the United Kingdom have been given permission to use hybrid human-animal embryos in research which aims to lead to the development of new therapies for debilitating human conditions such as Parkinson’s disease and stroke.
Newcastle University stem cell scientist Dr. Lyle Armstrong, who is based at the North East England Stem Cell Institute (NESCI) at the International Centre for Life in Newcastle, has received a licence from the Human Fertilisation and Embryology Authority (HFEA) to carry out research using human-animal cytoplasmic embryos. Another group -- the Stem Cell Biology Laboratory Wolfson Centre for Age-Related Diseases, at King's College London -- has also received a research license by HFEA to carry out research using hybrid embryos.
Dr. Armstrong says: “The award of the HFEA licence is great news. We initially applied for approval to use cow eggs as a means to understand the way they can convert skin cells into embryonic stem cells. Finding better ways to make human embryonic stem cells is the long term objective of our work and understanding reprogramming is central to this."
"Cow eggs seem to be every bit as good at doing this job as human eggs so it makes sense to use them since they are much more readily available but it is important to stress that we will only use them as a scientific tool and we need not worry about cells derived from them ever being used to treat human diseases," he said.
"Now that we have the licence we can start work as soon as possible. We have already done a lot of the work by transferring animal cells into cow eggs so we hope to make rapid progress.”
Until now, work on the development of therapeutic cloning has used human eggs from consenting IVF patients but these are in short supply. Animal eggs are considered to be a viable alternative for research to understand more about how cells behave.
At first the NESCI team would be working with cow eggs. The nuclear transfer technique would involve removing the nucleus of a cow egg - which contains most of its genetic information - and fusing the cow egg with the nucleus of a human cell such as a skin cell. The egg will then be encouraged to divide until it is a cluster of cells only a few days old called a blastocyst, or an early-stage cloned embryo.
The scientists would attempt to extract stem cells from the blastocyst after six days. Stem cells are building blocks that can grow into any type of tissue such as liver, heart and muscle cells. The quality and the viability of stem cells would then be checked to see if nuclear transfer technique has worked. The scientists would also be observing the way that the cells are reprogrammed after fusion to see if there are useful processes they could replicate in the laboratory. The embryo would have to be destroyed at 14 days old in accordance with the licence.
The eventual aim is to develop a way of creating stem cells to grow new tissue that is genetically matched to individual patients. For example, scientists hope to take a cell from a patient and re-programme it so that stem cells can be extracted to grow new tissue for damaged body parts without fear of immune rejection.
There is no possibility of allowing any of the animal hybrid cells to be used to treat patients but this approach will protect precious resources of human eggs at this early development stage and complement existing NESCI research using human eggs.
The studies will be heavily regulated under the conditions of the HFEA licence.
The HFEA statement on licensing of applications to carry out research using human-animal cytoplasmic hybrid embryos can be found at the following web address: http://www.hfea.gov.uk/en/1640.html
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