Stem Cell Introduction

Question 1

Origin of term:

Answer 1

• Ernest Haeckel (1868) is the first term of using “Stem Cells” > through how the stem of the tree of life has to come from one cell and has to come from its origin.
• Boveri 1892 > proposes stem cells are in a state between fertilised egg and committed germ cells.
• Hacker 1892 and Pappenheim 1905 > hematopoiesis

Question 2

What is a stem cell?

Answer 2

• Cells that can generate different specialised tissues through differentiation as well as making copies of themselves through self-replication
• Controlled balance between them

Question 3

Classification of stem cells:

Answer 3

TOTIPOTENT: Can produce all cell types, including trophoblast
PLURIPOTENT: can form the derivatives of the three germ layers: ectoderm, endoderm and mesoderm
MULTIPOTENT: different cell types from tissue or organ, less wide range as pluri and toti, neural blood and renal cells.
UNIPOTENT: only formed one single cell type

*There are different criteria for SCs: age of developement (different SCs between embryonic and adult, ESCs have a lot more range), tissue of origin (neural, hematopoeitic etc).

*In vivo, SCs have limited capacity to proliferate > they’re usually in the stem cell niche and have low capacity. The stimulation of th SCs can lead to fast cell cycling.