Embryonic vs. Adult Answers

Allison had some interesting questions about adult stem cells versus embryonic stem cells. I will try to answer some them here.

Adult stem cells are found in almost every tissue in the body, including the spinal cord, umbilical cord, bone marrow and the connective tissues of various organs whereas embryonic stem cells are only found in a developing embryo at the blastocyst stage. They are very difficult to obtain because they are scarce, and hard to find even with today’s techniques (Lillge). Once the adult stem cells are outside the animal, they are difficult to culture (grow). The potential (power) of Adult stem cells is somewhat debatable. Science has known about stem cells for around 30 years, and for a majority of that time, it was believed that adult stem cells could only differentiate linearly and only into the type of tissue from which they were originally discovered. This is what made them less potent than embryonic stem cells because an embryonic stem cell could technically become any one of multiple cell types of the organism. This is referred to as pluripotential. In his argument supporting adult stem cell research, Wolfgang Lillge, M.D. explains that tissue-specific stem cells found in animals, specifically mice, have the potential to transdifferentiate, meaning they can differentiate into a cell type different from the type of organ where they were found. For example, neuronal stem cells of mice have transformed themselves to blood stem cells and produced blood cells. A study by Catherine Verfaillie at the University of Minnesota suggests adult stem cells are actually as potent as embryonic stem cells (Westphal). This research is exciting but scientists within the field of stem cell research remain skeptical. Compared to embryonic stem cells, there is really no way of knowing which type of stem cell is more potent and some scientists maintain that embryonic stem cells are more promising than adult stem cells as far as treatments go. Supporters of stem cell research altogether claim that embryonic stem cell research must continue in order to understand the full potential of both adult and embryonic stem cells.
In the United States, it is lawful to use federal funds to conduct research on embryonic stem cell lines created prior to 2001. This limits the number of usable stem cell lines for research. In this way, embryonic stem cells are also hard to obtain because federal law is very restrictive. In some states, private funds are used to conduct embryonic stem cell research.



Westphal, Sylvia P. "Ethical Dilemmas." NewScientist.com. 10 Sept. 2006
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Westphal, Sylvia P. "Ultimate Stem Cell Discovered." NewScientist.com. 10 Sept.
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Lillge, M.D., Wolfgang. 21st Century Science & Technology Magazine. 10 Sept.
2006 stem_cell.html>.