This article, published in March 2008, reports on "the first time that cloned stem cells have been used to reverse disease in the same animals from which they were derived." In an experiment lead by Lorenz Studer, somatic nuclear transfer was used to create nearly 200 lines of cloned embryonic stem cells. Because Parkinson's disease is associated with a deterioration of dopamine-producing neurons, these stem cells were manipulated in vitro to form dopamine neurons, which were injected back into the mice (from which the embryonic stem cells were cloned). According to this article, "when mice received neurons grown from their own cloned stem cells, their neurological symptoms improved and they showed no signs of rejecting the transplanted tissue."
This experiment, as the article states, could have far-reaching implications. If the same process could be mimicked with human cells, we may be well on our way to a potential therapy for Parkinson's. But we still have a long way to go. As with many articles we have read, the tone of this report is guardedly optimistic. Yes, this experiment is an amazing breakthrough using the biotechnology of cloning. But mice and humans are a very different matter.
The article cautions its readers not to get their hopes up quite yet. Although the experimental procedure shows promise, the article warns that "only two groups, one in Britain and one in the US, have succeeded in cloning human embryos, and none has yet produced stem cells from a cloned embryo." So how, realistic, really, is it to believe that this therapy will soon be used in humans? The article also notes that cloning is hugely inefficient; scientists are still not able to consistently produce a viable line of cloned embryonic stem cells. On the contrary, "cloning... [usually] requires hundreds of eggs to produce a single viable clone, [which] is also expected to limit therapeutic applications."Despite the fact that these statements may seem negative in tone, the article overall is being more realistic than pessimistic. It notes that there are many intermediary steps that need to be taken before this kind of therapy can be applied to human patients. But it quotes experts who claim that the results are exciting and will eventually be useful in treating humans. One scientist is quoted as saying, “This is a very well conducted study that provides further proof-of-principle of the idea of ‘therapeutic cloning’ using a mouse model. Ideally one of the next steps will be to repeat the whole procedure with a monkey model, in which all the individual steps have now been established. This will allow much better tests of functional recovery and safety.”
Overall, the article presents a very fair few on the developing technology of therapeutic cloning. Progress is being made, but we should be careful not to count our chickens before they hatch. Scientists have still not mastered cloning completely; it is a fickle science that we still need to improve our understanding of, in order to utilize it most effectively. Although a decade has gone by since Dolly was cloned, and many people assumed that cloning would soon become common practice, we are still only making slow advances. But they are advances nonetheless, and should not be under-credited.
Readers should also notice the several controversies that are subtly raised in this article. First, is the "inefficiency of cloning." When hundreds of eggs are still required to produce a viable clone, how ethical is it to even consider using this technology in humans? Can we even imagine asking a woman to hyper-ovulate to this extent, in order to harvest her eggs in what still may be a failed attempt to produce an embryonic clone? I think we as a society will only consider these procedures acceptable in humans when the technology of cloning has been fine-tuned, and is much more efficient and consistent.
The article seems to agree. It states that "many scientists think that the main use of cloning will be to make laboratory models of disease for medical research, rather than treatments to be given to patients. This can be done by inserting human DNA into animal eggs, which will be allowed under the Human Fertilisation and Embryology Bill." Here, then, we will not be asking a woman to use her own eggs. Instead, animals will be made to bear that burden. But how ethical is this? How would animal rights activists respond to this? And how do we feel about the government stepping in to decide this issue with a federal bill?
Clearly, in trying to solve one controversy, scientists may run into another. Because cloning is still not fully understood or developed, many thorny issues abound. Hopefully, as scientists learn more about how to improve these technologies, some of these issues will no longer be a problem.
But for now, we must accept each small step forward that is made, and look to how we can improve and refine cloning technology to apply it safely and ethically to human patients.
C. Heard
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