Stem Cells

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Stem Cells
 DNA
 Gene - functional unit of heredity, a segment of
DNA located at a specific site on a chromosome;
genes direct the formation of proteins.
 Nucleus –
 Cell
- the basic unit of life, all living organisms
are made up of cells
• somatic cell • germ cell -
 Early
embryonic
cells unspecialized
 Three primary tissue
layers:
•
•
•
 All
tissues develop
from here
Stem cells = cells that have
the ability to divide for
indefinite periods and
 Remember:
Progenitor cells = partially
specialized cells that can
give rise
 Multipotent
–
 Pluripotent
–
 Totipotent
-
 “Excess” frozen
blastocysts
donated from fertility clinics
 Inner cell mass (embryo)
separated from trophoblast
(placenta)
 Cells dissociated and
cultured in laboratory
 Can be made to differentiate
using chemical signals
Dr. Hariom Yadav
8/1/2017
Dr. Hariom Yadav
8/1/2017
Dr. Hariom Yadav
8/1/2017

• “decision-making genes” (birth defects, cancer)

• human cell lines for all cell types

• replacement tissue for degenerative conditions
(Parkinson’s and Alzheimer’s disease, diabetes,
heart disease, stroke, arthritis)
 Insufficient
insulin
production in
 Insulin needed for
“
” cells
derived from stem
cells produce insulin
 Eliminates need for
insulin injections
 Understanding
of cellular events that
lead to
and

- Can stem cells be
modified to minimize tissue
incompatibility?
 Time of development and expense of
treatments
 Genetic
engineering
 Somatic cell
nuclear transfer
(
)
• develops into a
 Dolly the sheep
•
 Umbilical
cord blood
• Contains
and
cells (lower potency than hES)
• Patient specific
• Cord blood banks
 $2000 collection and $125/year storage fees
 Some public banks for donated cells
stem
 Induced
Pluripotent Stem Cells (iPS)
 Induced
• Show
Pluripotent Stem Cells (iPS)
potency than cord cells
• Low efficiency (recent improvements)
• Other problems



 Direct
Cell Reprogramming - 2011
• Turns one cell
 (ex. Skin cell  Neuron)
• Uses RNA, no virus DNA needed
• Eliminates need for
• Potential and problems are uncertain
 Self-donation
of
 Injected
(with or without chemical
treatment) into
 Not FDA approved
• Clinical trials underway (heart attack, spinal
cord injury, etc.)
• Many Americans seek overseas options






The United States has been criticized by some for being
too restrictive to stem cell-based research and therapies.
Should U.S. laws be relaxed to be more accommodating to
those wishing treatment?
A recent study by Duke University predicted that by the
year 2050, regenerative procedures based on stem cell
and other biotechnologies could extend an average
human life span by up to 100 years. Is this a desirable
goal?
Many biotechnologies are vastly expensive, yet much of
the basic research supporting these developments is paid
for by taxpayers. Who should benefit?

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