Stem Cells Flashcards
What are the three properties of Stem Cells?
1) Undifferentiated (or poorly differentiated)
2) Auto-renewing: two child cells have diverse fates
3) Replicative Immortality: retains ability to proliferate for entire life
Which are the two modalities by which stem cells produce child cells?
1) ENVIRONMENTAL SYMMETRY: fate of cells depends on extra-cellular environment (niche)
a) Can produce 1 stem cell and 1 progeny
b) Can produce 2 stem cells if both interact directly with niche
2) DIVISIONAL SYMMETRY: proteins inside the cell drive the stemness
> When stem cells divides, all determinants are given to only one of the two daughter cells (remains stem cell), while the other undergoes differentiation
What are the different sources of stem cells?
1) EMBRYONAL: obtained from days old fertilised eggs cells (also from in vitro non-fertilised egg without nucleus, with nucleus replaced from adult somatic cells > no risk of patient rejection)
2) FOETAL: obtained after miscarriage
- Mix of pluri-, multi-, oligo- and unipotent
- Studied for clinical use
3) UMBILICAL CORD BLOOD AND PLACENTA
- Multipotent
- Two types: Hematopoietic and Mesenchymal
- Stored in bank then available for stem cell transplant patients (must be compatible with major histocompatibility system of receiver)
4) ADULT: multi-, oligo-, or unipotent
a) Hematopoietic - from peripheral blood
b) Mesenchymal: from bone marrow
- these can be made to differentiate into different
cell types
- are found in other tissues: adipose, lymphatic,
umbilical, blood
- similar to embryonic SC without ethical issues
- can migrate > take part in tissue regeneration
- Found inside Wharton’s Jelly: structure inside
umbilical cord, with high differentiation ability
