05 September 2007

Possible Usefulness of Cybrid Embryos

Hybrid embryo15:30 Breaking News: As expected, the Human Fertilisation and Embryology Authority has given the go-ahead for the creation of human-animal embryos for research. The Government's U-turn follows an HFEA consultation that apparently showed the public were "at ease" with the idea when told it could pave the way for therapies for conditions such as Alzheimer's disease.

Which rather begs the question, as well as being told about some of the theoretical possible benefits, were the public also told about the even more probable risks? For, contrary to the impression given by some of those who argue in favour of creating human-nonhuman cybrids (cytoplasmic hybrids), some of the most relevant questions relating to the ethical discussion arise not from a consideration of human dignity or any religious grounds but rather from a scientific perspective and the actual possible usefulness of these entities.

In this regard, a report by BioCentre, The New Inter-Species Future?, made the following points:

1. Experiment needs confirming

The scientific merit and validity of experiments already undertaken (involving cow-human and rabbit-human hybrid embryos) remain to be confirmed by an independent research group repeating the procedures.

2. Interspecies mitochondrial-nuclear DNA dysfunction

The medical risks of implanting cells that contain a combination of animal and human mitochondrial DNA and human nuclear DNA are considerable, given that there are varying degrees of interspecies incompatibility between mitochondrial and nuclear functions. Furthermore, it should be noted that mitochondrial dysfunction has been discovered to be a key factor in many neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Since many of the diseases claimed to be treatable by therapeutic cloning are neurodegenerative, using stem cells from human-nonhuman cybrids would be liable to result in profound medical risks. Similarly, the use of such stem cells to treat heart or liver complaints could create a number of difficulties owing to the high level of mitochondrial activity in these organs.

3. Difficulty in interpreting results

Regarding the use of human-nonhuman cybrids for research into diseases, there are so many profound genetic and epigenetic flaws in cloned embryos (even using eggs of the same species), that to use embryos created by interspecies nuclear transfer would be liable to become a study of artefacts. In other words, it would be difficult to interpret the results. The potential of an experiment, to add to the sum of knowledge is only as good as its capacity for interpretation.

4. Risk of creating new diseases

There would also be risks of transmission of animal diseases to humans or the creation of new diseases if any of the cybrid embryos were implanted into a host or not kept in a bio-secure environment.

5. Immunological incompatibility

Finally, it should be noted that it is doubtful whether the cells arising from human-nonhuman cybrids, in which an animal egg is used would become more human with development from the perspective of immunological compatibility and could ever have clinical applications. Because of this, and other factors, it is extremely unlikely that they would be used for transplantation in human patients.

2 comments:

The Blunderer said...

To play the Devil's Advocate here: since those who oppose the creation of cybrid embryos are usually the same people who oppose the use of human embryos in research, and given that scientists want to create cybrid embryos because there are not enough egg donors willing to provide eggs for research purposes, surely the creation of sub-human cybrid embryos is morally less bad than the creation of fully human embryos and is something that should be perhaps welcomed by those who oppose human embryo research?

Sheila Johnson said...

This Bill seeking to legalise the creation of inter-species animal-human research violates the species barrier and as such is morally and ethically wrong. I would not wish to have a cure for diseases under this type of research even if I were a sufferer.

Another less well-known part of this Bill is that it removes the obligation on IVF clinics to have regard for the resulting child for a Father. How can the Conservative party contenance this when they have spoken up so strongly for the family? A child needs a secure family with both parents Mother and Father or at the very least to have awareness of whom both these individuals are.