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Overview
Mature tissue cell vs a stem cell
What is a stem cell?
How do we get stem cells?
What is the difference between embryonic and adult stem cells?
Why are stem cells medically important?
Stem cells
Photo: NIH Stem Cell Unit
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Stem cell sphere Cortical neurons
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Stem cell Terminology
Differentiation - cell specialization that occurs at the end of the developmental pathway.
Totipotent - a cell capable of giving rise to any of the cell types in the adult. In humans, the fertilized egg is totipotent until the eight-cell-stage.
Multipotent - can give rise to several other cell types, but those types are limited in number. An example is a blood stem cell that can develop into several types of blood cells, but cannot develop into brain cells.
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• Unlimited Cell Division• Pluripotent
Tissue cells
• Limited Cell Division• Found in tissues• Multipotent
Self-renewal decreases, Differentiation increases
• Blood, Brain etc.• Differentiated
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What is a Stem Cell?
Unspecialized cells
Able to self-renew without differentiating for extended periods of time
Types of stem cells Embryonic stem cells adult stem cells Umbilical cord stem cells
.
TIME 2001
Human blastocyst showing inner cell mass
Photo: Mr. J. Conaghan
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Embryonic Stem Cells Can Become Any Tissue in the Body
Blastocyst
Cultured laboratory stem
cells
Scientific manipulations entice stem cells to become specialized tissues (blood, muscle,
neuron, etc.).
Blood cellsMuscle cells
Neuron (brain) cells
Placenta cellStem cell
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Adult Stem Cells
Have two characteristics:
Self-renewal. They can give rise
to differentiated mature cells
Found in the brain, spinal cord, blood, muscle, the digestive system, retina, liver and pancreas.
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Umbilical cord stem cells
This blood is rich in cord blood stem cells that can be used to generate blood cells and cells of the immune system.
can be used to treat a range of blood disorders such as
Leukaemia or sickle cell anaemia.
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What Diseases Could Be Impacted by Stem Cell Research?
Millions of people suffer from diseases which might be alleviated by stem cell transplantation technologies.
Examples include cardiovascular disease, autoimmune disease, diabetes, osteoporosis, cancer, Alzheimer’s disease and Parkinson’s disease.
Stem cell treatment could potentially help patients with severe burns, spinal cord injuries, or birth defects.
Science (2000) 287:1423.