EMBRYONIC STEM CELLS

Question 1

Talk about the ESC in general

Answer 1

Characteristics of ESCs (potency)
Where we find them
How we can derive them

Question 2

Historic timeline of ESCs: the most important steps

Answer 2

1981: identification and isolation of mouse ESCs by Martin Evans
1984: creation of germline chimeras from an embryonic teratocarcinoma cell lines by Martin Evans
1998: identification and isolation of human ESCs by James Thompson
2006: creation of IPSC by Yamanaka
2010: first clinical trial based on human ESCs by Geron company
2013: hESCs produced from fetal cells by therapeutic cloning
2014: hESCs produced from somatic adult cells by therapeutic cloning

Question 3

Differences between human and mouse ESCs

Answer 3

hESCs grow slowly, they need a feeder layer, they form more flat radical colonies, more easily dissociated in single cells (mESCs form more spherical colonies). They express different
stage-specific embryonic antigens (hESCs 3 e 4, mESCs 1a).
mESCs can be used to produce germline chimeras, not possible with hESCs. Less information about the hESCs: we only know that they can colonize the three germ layers and form teratomas in vivo.
More safety issues for the hESCs.

Question 4

Are the ESCs a clinical reality now?

Answer 4

Now, there are still many problems:
- ethical issues because they derive from embryos (Law 40/2004)
- immunogenicity
- tumorigenic potential because we are not sure to obtain 100% of differentiated cells
- functional integration in the host tissue

Question 5

What are the main fields of application of ESCs?

Answer 5

• diabetes mellitus (USA clinical trial, 2014)
• macular degeneration
• Parkinson’s disease (4 clinical trials going on with different starting materials but the same aim)