Stem Cells Flashcards
How is adult body formed from a single cell
Cell division - symmetric and asymmetric Differentiation into specific cell types Migration to organise into complex structures Apoptosis programmed cell death
Hematopoietic Stem Cells (HSC)
Quiescent (asleep) in Bone Marrow
>Hypoxic niche
>Slow self-renewal
>No differentiation
Activation/Mobilisation to Blood
>Signals from the blood - Chemokines/Cytokines >Migration
>Expansion - symmetrical cell division Specification – asymmetric cell division
Mesenchymal Stem Cells
Quiescent (asleep) in Bone Marrow & Body Fat
>Hypoxic niche
>Slow self-renewal
>No differentiation
Activation/Mobilisation to Multiple Organs
>Migration
>Expansion - symmetrical cell division Specification – asymmetric cell division
What are the 2 types of stem cell renewal
Asymmetrical cell division
Symmetric stem cell commitment(differentiation)
Hierarchy of stem cells
-totipotent=zygote
-pluripotent=embryo
-multipotent=tissue stem cell,progenitor cells
-unipotent=terminally differentiated cells
Challenges for Regenerative Medicine
Immune rejection of hES cells
hES cells express HLA antigens
Immune matching required, as for other tissues
Risk of immune suppression
Ethical considerations of using human ES cells
• All current human ES cell lines are derived from donated embryos.
• 14 day rule.
• Unwanted or discarded embryos.
• Obtained after ethical approval and by informed consent. Research consent
Clinical consent
• Moral and religious objections are valid.
• Different rules for different countries even within the EU.
Induced Pluripotent Stem (iPS) Cells
-no need for immune matching
Honing capacity
Tendency to hone to damaged tissue sites
Differentiation potential
Capacity to differentiate into multiple cell types
Secretory capacity
Naturally produce reparatory growth factors and cytokines
Immunomodulation
Can help dampen inflammation
