amar deep stem cell lu
TRANSCRIPT
Introduction to Stem Cells
By
AMAR DEEPPh. D. Scholar
Department of Zoology
University of Lucknow
Lucknow – 226007 (India)
A Life Story…
Embryonic Stem Cells
blastocyst - a very early
embryo
Tissue Stem Cells
fetus, baby and
throughout life
Stem cells are unspecialized cells that are thought to be
able to reproduce themselves indefinitely and under the
right conditions, to develop into a wide variety of
mature cells with specialized functions.
What are Stem Cells?
Stem cells can:
• Self-renew to make more stem
cells.
• Differentiate into a specialized cell
type.
Definitions:
Totipotent:Able to give rise to all type of differentiated cells including
placenta. eg. Single cell embryo.
Multipotent:Stem cells that can become only a few types of cells are called
multipotent. eg. Fetal tissue, Cord blood, Adult stem cells.
Pluripotent:Stem cells that can become many types of cells in the body are called
pluripotent. Undifferentiated inner cell mass of the blastocyst.
Embryonic Stem Cells
Where do embryonic stem cells come from?
8-cell blastocystfertilised egg
2-cellegg
Day 0 Day 1 Day 2 Day 3 Day 6
Inner cell mass
Advantages of E.S. Cell
1. Flexible-have the potential to make any cell.
2. Immortal-can provide an endless supply to cells.
3. Availability-embryos from in vitro fertilization
clinics.
Disadvantage of E.S. Cell1. Difficulty to differentiate uniformly into a target
tissue.
2. Immunogenic ie. cells from a random embryo
donor may be rejected after transplantation.
3. Tumorigenic ie. capable of forming tumors.
4. Destruction of developing human life.
Tissue Stem Cells: Adult Stem Cells
• Adult stem cell is an undifferentiated (unspecialized) cellie. found in differentiated (specialized) tissue.
• Also includes stem cells isolated from fetal and cordblood.
• Reside in most tissues of the body where they areinvolved in repair and replacement
Adult Stem Cells
Brain Skeletal
Muscle
Liver, Skin,
GIT &
Pancreas
Bone Marrow &
Blood Stream
Eye dental pulp
& Eye
Sources of Adult Stem Cells
Disadvantage of Adult Stem Cell• Limited quantity- can sometimes be difficult
to obtain in large numbers.
• Finite- may not live as long as embryonic stemcell in culture.
• Less flexible- may be more difficult toreprogram to form other tissue type.
Why are adult stem cells preferable to embryonic stem cells ?
• Adult stem cells are naturally exist in our bodies and they provide a natural repair mechanism for many tissue. eg. hematopoietic stem cells.
• They belong in the microenvironment of an adult body, where they never cause tumors and immune system reactions.
• Adult stem cells have already been successfully used in human therapies.
Pluripotent Stem Cells• Pluripotent Stem Cells are descendants of the
totipotent stem cells of the embryo.
• Similar properties to embryonic stem cells as candifferentiate into many different tissue types.
• Terminally differentiated cells induced to becomepluripotent with in vitro manipulation k/a inducedpluripotent stem (iPS) cells.
Induced pluripotent stem cells (iPS cells)
cell from the body
‘genetic reprogramming’= add certain genes to the cell/culture condition
induced pluripotent stem (iPS) cellbehaves like an embryonic stem cell
Advantage: no need for embryos!all possible types of
specialized cells
culture iPS cells in the lab
differentiation
• Apoptosis
No apoptosis in stem cells
• Telomere
No shortening of telomere in stem cells
• DNA Methylation
Minimum DNA methylation in stem cells
Stem cells specialty
Identification of stem cells
• Cell morphology
• Expression of unique cell surface antigens
• Characterization of biochemical markers such as tissue
specific enzymatic activity
• Expression of genes that are unique to a particular cell
type
• Nuclear chromosomal karyotype to access genetic
stability
Applications of Stem Cell Research
Animal model testing for pharmaceutical research
Use of stem cells in transplantation and cellreplacement therapy
Conservation of endangered species
Understanding fundamental events in embryonicdevelopment
Therapeutic delivery system
To resolve mysteries of developmental biology
To investigate genes involved in differentiation anddevelopment
Cell banking for research applications
Applications of Stem Cell Research
Study cell
differentiation
Drug screening
&
Toxicity testing
Bone Marrow
for leukemia &
chemotherapty
Nerve cells for
Neurodegener-
ative disorders
Heart muscle
cells for heart
disease
Pancreatic
islet cells for
diabetes
Pluripotent
Stem Cells
Cell replacement therapy
Therapeutic Use