By: Maria M. C. de Gouveia, Dept. Biology, University of Madeira, Portugal;
Enrique Ianez Pareja, Dept. Microbiology, University of Granada, Spain
Donald Sakaguchi, Neuroscience Program, Iowa State University, USA; Heloisa G. dos Santos, Hospital S. Maria and Faculdade Medicina, Univ. de Lisboa, Portugal; Peter Whittaker, National University of Ireland, Ireland
Following fertilization, a human egg divides several times during the first few days to produce a spherical mass of undifferentiated cells. During this stage the cells are totipotent, i.e. they are each able to give rise to an embryo. In the next stage some of the cells of the embryo give rise to what is called the inner cell mass. These cells are no longer totipotent. The cells can be removed from the embryo and grown in culture. The resultant cells are referred to as embryonic stem cells. (Removal of the cells from the embryo at this stage causes its destruction). In culture the embryonic stem cells can be induced to differentiate into several types of specialized cell (e.g. muscle, nerve, liver). It is expected that in the future these cells will be able to be used for treatment of degenerative diseases (including Parkinson's disease) and some injuries.
Five years ago, Mr. and Mrs. Smith were presented to an in vitro fertilization (IVF) clinic in their local hospital. After a number of attempts, eight eggs were successfully fertilized. Three of these were implanted and eight months later Mrs. Smith gave birth to twins, but only one baby survived. The Smith's requested that the surplus embryos be frozen for possible further implantation at a later stage. No further possibilities for use of the embryos were suggested at this time by the hospital staff.
Tragically Mr. and Mrs. Smith died in an automobile accident one-year later. Two years after this the IVF clinic tried to contact the couple to determine their wishes concerning the disposition of the frozen embryos, and at this stage learned of their deaths. In the hospital there was a research group actively researching therapies for Parkinson's disease. They had already presented a proposal to the hospital Ethics Committee to be allowed to use stem cells derived from frozen embryos for research in Parkinson's disease therapy and the project had been approved.
The Director of the research team approached the IVF clinic to see whether they had surplus frozen embryos that they might use. The head of this clinic offered the surplus Smith embryos to the Director of the research team.
In the country where this happened, there is no clear legislation concerning embryo stem cell research.
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