April 2010
Written by Erica Brown and Stacey Herzer

Human ESCs are derived from human embryos at a very early stage of embryonic development (usually only a few days post fertilization).  At this stage of development, the embryos are a ball of around 30 cells and have no recognizable human form, but they do have the potential to become any cell type in the human body. That’s why they’re called pluripotent (Pluri = many) (1). Scientists hope to understand how to control the differentiation of these the cells so that they can be used as a therapy to treat many diseases where cells are sick, damaged, and need to be replaced.  The use of these cells for research or therapy cause fierce ethical debates because some people think human embryos should have the same rights as born humans and they think that ESC research sacrifices human life for scientific progress.  Most human embryonic stem cells used in research in Canada are taken from left over embryos created during IVF (in vitro fertilization) procedures. Instead of discarding the embryos, scientists have obtained couples’ consent to have them used for research. While other methods of obtaining human ESCs are possible (including embryos of donor eggs and sperm, somatic cell nuclear transfer, and aborted embryos), IVF embryos are the source approved by the Canadian Institutes of Health Research (CIHR) who in 2007 revised a set of guidelines originally created in 2001 for determining stem cell projects that could get public funding from the government of Canada (2).

If you are interested in more information on stem cells, please see the following:

• Stem Cell Fundamentals

References:

• Nussbaum RL et al. Thompson and Thompson Genetics in Medicine. 6th ed. 2004. Saunders.
• Canadian Institute of Health Research (CIHR). Updated Guidelines for Human Pluripotenet Stem Cell Research. June 28 2006.