health biotechnology stem cell lecture 20: biotechnology; 3 credit hours atta-ur-rahman school of...
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Health BiotechnologyStem Cell
LECTURE 20:
Biotechnology; 3 Credit hours
Atta-ur-Rahman School of Applied Biosciences (ASAB)
National University of Sciences and Technology (NUST)
What are Stem cells
• Unspecialised cells lacking any tissue-specific structure
• Can give rise to specialised cells through the process of differentiation
• Stem cells are the raw material from which all of the body’s mature, differentiated cells are made.
• Stem cells give rise to brain cells, nerve cells, heart cells, pancreatic cells, etc.
Stem Cells !!!
stem cell
stem cell
SELF-RENEWAL
(copying)
specialized celle.g. muscle cell, nerve cell
DIFFERENTIATION
(specializing)
Stem Cell Definition
• A cell that has the ability to continuously divide and differentiate (develop) into various other kind(s) of cells/tissues
• Stem Cell
Kinds of Stem Cells
Cell type Description Examples
Totipotent Each cell can develop into a new individual
Cells from early (1-3 days) embryos
Pluripotent* Cells can form any (over 200) cell types
Some cells of blastocyst (5 to 14 days)
Multipotent*Cells differentiated, but can form a number of other tissues
Fetal tissue, cord blood, and adult stem cells
*The pluripotent stem cells are in fact derived from totipotent stem cells. The pluripotent stem cells can develop into any cell type except for the extra-embryonic tissue. *Multipotent progenitor cells can give rise to many but limited types of cell. For example, a hematopoietic cell can give rise to several types of blood cells (i.e. red blood cells, white blood cells, platelets, etc.)
Day 1Fertilized egg
Day 1Fertilized egg
Day 22-cell embryo
Day 22-cell embryo
Day 3-4Multi-cell embryo
Day 3-4Multi-cell embryo
Day 5-6BlastocystDay 5-6
BlastocystDay 11-14Tissue Differentiation
Day 11-14Tissue Differentiation
Totipotent Stem Cells
Stem Cell types: Origin
Stem Cells comprise the following Types1. Embryonic Stem Cells2. Fetal Stem Cells3. Umbilical Stem Cells4. Adult Stem Cell
1- Embryonic Stem Cells
• Usually they are pluripotent cells• Most valuable can become into any type • 1998 first human embryonic cell was grown• In invitro fertilization (IVF) • Extra embryo that are not implanted are
frozen
2- Fetal Stem Cells
• These are also pluripotent• Fetus brain tissue• They are excellent source of cells for adults
with Parkinson’s disease
3- Umbilical Stem Cells
• The cells from cord blood are multipotent stem cell.• They can naturally develop into blood cells and
immune cells• Cord blood cells are highly suitable because they
have less rejection.• They also lack mature immune cells that can attack
the recipient body.• Cord cells can be store and it can be denoted by
woman after giving birth.• Cord blood bank
4- Adult Stem Cell
• Numerous multipotent adult stem exist in body
• Can develop into cells of specific types of the tissue
• These are least plastic in term of differentiation
• Much research is focused in this area
Induced pluripotent stem cells (iPS cells)
adult cell
‘genetic reprogramming’= add certain genes to the cell
induced pluripotent stem (iPS) cellsbehave like embryonic stem cells
Advantage: no need for embryos!
all possible types ofspecialized cells
culture iPS cells in the lab
differentiation