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Derivation of human embryonic stem cells

Stem Cells_Derivation of human embryonic stem cells.gif
© DRZE

Figure 3: For the derivation of stem cells the trophoblast is destroyed either by using antibodies or laser technology. The inner cell mass is placed and cultivated in a special culture medium. These cell culture conditions allow for continued cell grow into ES-cells. These can either differentiate infinitely or can be triggered to differentiate into different cell types by means of adding specific growth factors.

Imaginable ways of obtaining human stem cells 

 1. Obtaining and cultivating embryonic stem cells from

    (1) human germ cell tumours (EC cells) 
    (2) human foetuses (EG cells) 
    (3) human embryos (ES cells), which can be produced or obtained through 

         (a) rinsing (lavage) of the uterus

         (b) in-vitro-fertilisation (IVF)
               (i) as “surplus” embryos in the context of medically assisted 
                   reproduction
               (ii) specifically for research purposes (“research embryos”)
                    (α) natural gametes
                    (β) gametes generated from ES cell lines (hypothetically)

         (c) cloning techniques
               (i) embryo splitting (blastomere separation)
               (ii) transfer of a cell nucleus to an oocyte (somatic cell nuclear transfer), 
                    in which regard the oocytes used can be
                      (α) human egg cells
                      (β) egg cells from animal species

         (d) alternative methods of generating human ES cells
               (i)   from embryos after stage-specific external inhibition of their 
                     development
               (ii)  generation of embryos through parthenogenesis
               (iii) generation of embryos using genetically manipulated gametes 
               (iv) generation of embryos by means of altered nuclear transfer (ANT) 
               (v)  generation of ES cells through reprogramming of somatic cells

 2. Obtaining and cultivating tissue-specific stem cells from

     (1) child and adult somatic tissues (adult stem cells)
     (2) blood or tissue from the umbilical cord

This overview is based on the illustration by Heinemann / Kersten (2007):

Heinemann, T. / Kersten, J. (2007): Stammzellforschung. Naturwissenschaftliche, rechtliche und ethische Aspekte. Ethik in den Biowissenschaften - Sachstandsberichte des DRZE, Bd. 4. Freiburg i.B.: Alber. Online Version (German)

For further information see:

On the derivation of human stem cells through transfer of a cell nucleus to an oocyte (research cloning), which has not been successfully realized yet, see the DRZE “In Focus” issue on “Cloning for research purposes”. Online Version

In the module „Derivation of Human Embryonic Stem Cells”, three alternative methods for the derivation of human ES cells are presented in addition to (d). In these, the aim is to derive ES cells without arresting the development of the embryos. They have not been used widely so far.