Unknowns in Stem Cell/Cloning Research

Questions
      • It is uncertain that human embryonic stem cells in vitro can give rise to all the different cell types of the adult body.
      • It is unknown if stem cells cultured in vitro (apart from the embryo) will function as the cells do when they are part of the developing embryo.
      • It is unknown if embryonic stem cell lines will continue to proliferate indefinitely or will undergo genetic Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations and fail to be useful.
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Slide 21 of 63


Human embryonic stem cells have been studied only recently, so their capabilities are, as of yet, unknown. In theory, the embryonic stem cells are able to form every cell type (which is what they do in the embryo). However, the conditions in culture might not be able to recreate the conditions that give rise to many tissues in the intact embryo. In addition to these unknowns, it is uncertain that the cultured stem cells will function the same as cells that have been developed within the embryo. For example, in a recent study, insulin-producing cells derived from murine embryonic stem cells failed to produce the insulin when transplanted into mice, but only formed tumors.1 In addition, it is uncertain that these lines will continue to proliferate indefinitely without undergoing genetic Permanent structural alterations in DNA, consisting of either substitutions, insertions or deletions of nucleotide bases.mutations that render them useless. According to the President's Council on Bioethics:

"It is not yet known whether any preparation of human ES cells (generally believed to be much longer-lived than adult stem cells) will continue to grow 'indefinitely,' without undergoing genetic changes."2


References Top of page

  1. S. Sipione et al. 2004. Insulin expressing cells from differentiated embryonic stem cells are not beta cells. Diabetologia 47: 499-508.

  2. "Recent Developments in Stem Cell Research." Monitoring Stem Cell Research. The President's Council on Bioethics, January 2004.

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Last Modified August 2, 2004

 

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