Stem Cells: The Basics
What are stem cells?
o “Special cells”
1. Self-Renewal - Use mitotic cell division to “renew themselves” infinitely
 The parent cells divide into two genetically identical daughter cells
2. Potency – Holds the potential to differentiate into different types of cells
 They repair/replace damaged tissues using cellular differentiation, the process
in which a non-specialized cell can develop into a specialized cell
Primary types of stem cells?
1. Embryonic Stem Cells
o Pluripotent: hold the
ability to differentiate into
any type of cell (brain cell,
nerve cell, etc)
1. Extracted from the
blastocyst, an early-stage
embryo
2. Grown scientifically into
any type of cell/tissue
3. Replanted in the human
body to replace the
damaged cells/tissues (OR)
Used in research since they
can produce unlimited
copies of themselves for
testing purposes
o Controversy:
extraction of embryonic stem cell requires the
destruction of a human embryo
2. “Somatic (related to the body)” or “Adult” Stem Cell
o Multipotent: hold the ability to differentiate into only some types of cells
Stem Cells: Therapeutic Uses
How they are extracted
 Embryonic Stem cells can be extracted and put on a culture plate. On the
plate, the stem calls multiply and divide, fostering more cells, which can be
kept for a long time if under the right environment conditions
 They can be instigated to grow into different cell types by adding different
growth factors/hormones while they are still in the process of growth in the
culture plate
 These differentiated cells can help replace damaged cells and organs, and will
be specific to which human organ cell type they are. For example skin, heart,
nerve cells, and more
 However, once these cells start differentiating, it cannot be undone
Cell based Therapy
 Most important uses of these stem cells is cell- based therapy
 Organs and human tissue are imperative in curing diseases and damaged
cells, but are scarce. Stem cells, which can be grown indefinitely and
specialized for each organ or tissue, can overcome this issue
 Injuries that stem cells can cure include but are not limited to
o Spinal cord injuries
o Heart disease
o Stroke
o Burns
o Diabetes
o Arthritis
o Alzheimer’s disease
 The way it works is, for example, in heart disease, stem cells can either
replace or regenerate the damaged muscle and tissue
 These new healthy muscles can be transplanted into the patient
 Another example is bone marrow transplant, which is usually required when
bone marrow is damaged or has been destroyed as an effect of
chemotherapy. In this, a donor with similar genetic type donates stem cells
from his/her bone marrow
Therapeutic Cloning
 Extracting stem cells from those that are already born which can be used for
that individual in order to avoid any immune system reaction
Difficulties and Risks
 Producing lines of differentiated cells can take a long time
 Embryonic stem cells, when tested on mice, caused tumors
 Immune response can hinder the productivity of stem cells, and can be
dangerous for the patients health
 Hence, after a stem cell transplant, there would have to be treatment for the
incompatibility with the immune system
 Moreover, there is still a lot of uncertainty about stem cells and research is
continuing, so other risks cannot be anticipated yet
Bibliography
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2010.
<http://stemcells.nih.gov/info/basics/>.
“Stem cell diagram.” Online Image. 2006. Wikipedia. Web. 26 Aug. 2010
<http://en.wikipedia.org/wiki/File:Stem_cells_diagram.png>
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2010
<http://gateway.kwantlen.bc.ca/talk/Courses_Spring_2009.html>
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before these
potential uses will be realized? [Stem Cell Information]." NIH Stem Cell
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<http://stemcells.nih.gov/info/basics/basics6.asp>.
(Note that Wikipedia was used only as an image source)