Organs Without Donors by Cloning
It is a transplant surgeon's dream: an endless supply of organs and tissue matched to their recipient. And it might happen, if a radical new technology exploits the nuclear transfer technique that underpins cloning.
A cow egg stripped of its own nucleus would be fused with a human cell to create an embryo that begins to grow in the test tube. The embryo would not viable in the long run, but embryonic stem cells would be taken from that embryo: crucially, these could develop into a wide range of tissues.
The techniques need further work, but according to New Scientist many of the key steps have quietly been accomplished.
Among the earliest medical pay off could be the production of nerve or heart muscle cells for transplant. But ultimately entire organs might also be created. Because these tissues and organs would be cloned from the patient's own cells, there should be little problem with immune rejection.
This could provide a desperately needed solution to the chronic shortage of donated human organs.
Cloning involves the production of a group of identical cells or organisms that all derive from a single individual. It is not known when or how cloning humans might become a real possibility, but it is known that there are two theoretical ways in which humans could be cloned.
The first way involves splitting an embryo into several halves and creating many new individuals from that embryo. The second method involves taking cells from an existing human being and cloning them, in turn creating other individuals that are identical.
The technological problems and ethical issues surrounding cloning are virtually impossible to avoid, but the idea of cloning humans cannot be written off.
Cloning captured public attention when Scottish scientists at the Roslin Institute startled the world by announcing the birth of a sheep named Dolly that had been cloned by combining the nucleus of an adult mammary cell and an enucleated sheep egg.
Like many others, we believe that any plan to ban research on cloning human cells is seriously misguided. To make our position clear, it is important to explain the biology of somatic-cell nuclear transfer and then point out how this approach may have unique therapeutic applications. The experiments under discussion involve transferring a human diploid nucleus into a human ovum from which its native nucleus has been removed. In principle, the donor nucleus could be taken from a fetal stem cell or an adult somatic cell.
If the nucleus comes from an adult somatic cell, many complex and as yet unproved transformations would have to occur. First, the adult cell nucleus would have to fuse with an enucleated ovum and then dedifferentiate in its new environment. Second, the new cell would have to be capable of dividing into daughter cells, which would have to be pluripotent stem cells with the capacity to differentiate into specific tissues such as muscle, skin, heart. Finally, the genetic makeup of these stem cell or the newly differentiated cells might have to be altered so that the tissue could then be used to treat human disease.
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