HC13 - Stem cells Flashcards
stem cells (3)
- unspecialized cells that are able to proliferate over a longer period of time
- pluripotent
- essential for formation, maintenance and repair of tissues
cell division of stem cells
self-renewal
zygote
totipotent
blastocyst > embryonic stem cells (ECS)
pluripotent
germ layers > somatic stem cells in tissues
multipotent
asymmetrical divison of stem cells
- environmental asymmetry
- divisional asymmetry > marker to remain a stem cell already present
natural stem cells (4)
- embryonic
- neonatal
- adult/somatic
- cancer stem cells
artificial stem cells
induced pluripotent stem cells
ECS differentiation in culture occurs because of
environmental factors
limitations in development hECS-based therapies (4)
- ethical objections
- xeno-free system
- presence of undifferentiated hECSs
- graft immune rejection
adult hematopoietic stem cells for
bone marrow transplant > 1956: identical twins
peripheral blood stem cells (2)
- G-CSF or GM-CSF mobilized from bone marrow
- apharesis
neonatal hematopoietic stem cells in
umbilical cord blood
brain
neural stem cells
teeth
dental pulp stem cells
bone marrow
mesenchymal and hematopoietic stem cells
muscle and adipose tissue
mesenchymal stem cells
testicles
testicular stem cells
intestinal stem cell niche
Paneth and pericryptal cells > stem cells in between Paneth cells
niche factors
WNT3, DLL4, EGF, Noggin
niche factors for (3)
- mediating dormacy
- activation/maintenance > homeostasis
- differentiation/proliferation > damage and regeneration
induced pluripotent stem cells (IPS cells) (2)
- cellular reprogramming
- epithelial cells > stem cells
transcription factors IPS
cMYC, OCT4, SOK2, KLF4
limitations IPS cells (4)
- low succes rate reprogramming > 0.01-0.1%
- genomic intergration of transcription factors
- tumor formation > use of oncogenes
> incomplete reprogramming > epigenetics
