Obtaining embryo stem cells without injuring the embryo: Shedding light on the hype

Publié le : 31 January 2014

 On 27 January 2014, the Nature Communication journal published the "discovery" made by the team led by Dr. Karl Tryggvason, Professor of Medical Chemistry at the Karolinska Institute in Sweden. This discovery is presented as the introduction of a "new procedure which facilitates the large-scale production of human embryo stem cells of a high clinical quality without jeopardising embryo viability" or even as "a major step forward for stem cell research, regenerative medicine and cell therapy". 

 
Scientists collect one in eight embryo cells by biopsy. According to scientists, embryo biopsy, which is also used in pre-implantation diagnostics, involves the sampled cell to be used to obtain numerous human embryo stem cells (hESC) acknowledged for their pluripotence (capacity to differentiate into any type of bodily tissue). The scientists claim that embryo biopsy from a cell can be carried out without any damage to the embryo, thereby allowing it to be refrozen and implanted.
It should be noted that the discovery made by Dr.Tryggvason’s team, which is perceived as "limiting ethical obstacles" had already been mentioned in a publication by Dr. Lanza et al. in October 2005 (1). "Biopsy sampling of an embryo blastomere during the segmentation stage" had therefore already been carried out in an attempt to obtain hESC lines. But the authors of this publication had not managed to satisfactorily multiply the sample cell (called a blastomere). The embryo that was collected during biopsy could not be reimplanted in the end. The ethical problem of harvesting human embryo stem cells was not, therefore, resolved.        

Dr. Tryggvason’s publication, which reproduced Dr. Lanza’s  method by improving the blastomere culture medium, does not mention re-implantation of biopsied embryos and does not show that a single blastomere is sufficient to produce a sufficient number of embryo stem cells.

Hype therefore surrounds research which actually involves handling the embryo and which cannot consequently be qualified as ethical even though the embryo is not destroyed and can be subsequently reimplanted (which has yet to be proven).  

(1) New method of obtaining embryonic stem cells could reduce embryo wastage, European Society for Human Reproduction and Embryology, released 20 june 2005..Baha A, Takeuchi T, Tanaka N, Neri QV, Rosenwaks Z, Palermo GD, Examination of individual blastomeres as a source of stem cells, Session 04, Stem Cells, Abstract O-018, p.i7, Abstracts of the 21st Annual Meeting of the European Society of Human Reproduction and Embryology, Copenhagen, Demnark, 19-22 June 2005, Human Reproduction, June 2005, vol.20, suppl.1, p.i7. et Y.Chung, I.Klimanskaya, S.Becker, J.Marh, S-J.Lu, J.Johnson, L.Meisner, R.Lanza,Embryonic and extraembryonic stem cell lines derived from single mouse blastomeres, Nature, 12 january 2006, pp.216-219.

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