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. 2004 Aug;30(4):410–413. doi: 10.1136/jme.2003.002386

Stem cells, embryos, and the environment: a context for both science and ethics

C Towns 1, D Jones 1
PMCID: PMC1733909  PMID: 15289540

Abstract

Debate on the potential and uses of human stem cells tends to be conducted by two constituencies—ethicists and scientists. On many occasions there is little communication between the two, with the result that ethical debate is not informed as well as it might be by scientific insights. The aim of this paper is to highlight those scientific insights that may be of relevance for ethical debate.

Environmental factors play a significant role in identifying stem cells and their various subtypes. Research related to the role of the microenvironment has led to emphasis upon "plasticity", which denotes the ability of one type of stem cell to undergo a transition to cells from other lineages. This could increase the value given to adult stem cells, in comparison with embryonic stem cell research. Any such conclusion should be treated with caution, however, since optimism of this order is not borne out by current research.

The role of the environment is also important in distinguishing between the terms totipotency and pluripotency. We argue that blastocysts (early embryos) and embryonic stem cells are only totipotent if they can develop within an appropriate environment. In the absence of this, they are merely pluripotent. Hence, blastocysts in the laboratory are potentially totipotent, in contrast to their counterparts within the human body which are actually totipotent. This may have implications for ethical debate, suggesting as it does that arguments based on potential for life may be of limited relevance.

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Selected References

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  1. Abkowitz Janis L. Can human hematopoietic stem cells become skin, gut, or liver cells? N Engl J Med. 2002 Mar 7;346(10):770–772. doi: 10.1056/NEJM200203073461012. [DOI] [PubMed] [Google Scholar]
  2. Blau H. M., Brazelton T. R., Weimann J. M. The evolving concept of a stem cell: entity or function? Cell. 2001 Jun 29;105(7):829–841. doi: 10.1016/s0092-8674(01)00409-3. [DOI] [PubMed] [Google Scholar]
  3. Brazelton T. R., Rossi F. M., Keshet G. I., Blau H. M. From marrow to brain: expression of neuronal phenotypes in adult mice. Science. 2000 Dec 1;290(5497):1775–1779. doi: 10.1126/science.290.5497.1775. [DOI] [PubMed] [Google Scholar]
  4. Butler D. France opens door to use of embryos in stem-cell research. Nature. 2000 Dec 7;408(6813):629–629. doi: 10.1038/35047245. [DOI] [PubMed] [Google Scholar]
  5. D'Amour Kevin A., Gage Fred H. Are somatic stem cells pluripotent or lineage-restricted? Nat Med. 2002 Mar;8(3):213–214. doi: 10.1038/nm0302-213. [DOI] [PubMed] [Google Scholar]
  6. D'Amour Kevin A., Gage Fred H. Are somatic stem cells pluripotent or lineage-restricted? Nat Med. 2002 Mar;8(3):213–214. doi: 10.1038/nm0302-213. [DOI] [PubMed] [Google Scholar]
  7. Doerflinger Richard M. The ethics of funding embryonic stem cell research: a Catholic viewpoint. Kennedy Inst Ethics J. 1999 Jun;9(2):137–150. doi: 10.1353/ken.1999.0011. [DOI] [PubMed] [Google Scholar]
  8. Ferrari G., Cusella-De Angelis G., Coletta M., Paolucci E., Stornaiuolo A., Cossu G., Mavilio F. Muscle regeneration by bone marrow-derived myogenic progenitors. Science. 1998 Mar 6;279(5356):1528–1530. doi: 10.1126/science.279.5356.1528. [DOI] [PubMed] [Google Scholar]
  9. Galli R., Borello U., Gritti A., Minasi M. G., Bjornson C., Coletta M., Mora M., De Angelis M. G., Fiocco R., Cossu G. Skeletal myogenic potential of human and mouse neural stem cells. Nat Neurosci. 2000 Oct;3(10):986–991. doi: 10.1038/79924. [DOI] [PubMed] [Google Scholar]
  10. Jackson K. A., Majka S. M., Wang H., Pocius J., Hartley C. J., Majesky M. W., Entman M. L., Michael L. H., Hirschi K. K., Goodell M. A. Regeneration of ischemic cardiac muscle and vascular endothelium by adult stem cells. J Clin Invest. 2001 Jun;107(11):1395–1402. doi: 10.1172/JCI12150. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Jackson K. A., Mi T., Goodell M. A. Hematopoietic potential of stem cells isolated from murine skeletal muscle. Proc Natl Acad Sci U S A. 1999 Dec 7;96(25):14482–14486. doi: 10.1073/pnas.96.25.14482. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Jones D. Gareth, Telfer Barbara. Before I was an embryo, I was a pre-embryo: or was I? Bioethics. 1995 Jan;9(1):32–49. doi: 10.1111/j.1467-8519.1995.tb00299.x. [DOI] [PubMed] [Google Scholar]
  13. Kopen G. C., Prockop D. J., Phinney D. G. Marrow stromal cells migrate throughout forebrain and cerebellum, and they differentiate into astrocytes after injection into neonatal mouse brains. Proc Natl Acad Sci U S A. 1999 Sep 14;96(19):10711–10716. doi: 10.1073/pnas.96.19.10711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Matsuoka S., Ebihara Y., Xu M., Ishii T., Sugiyama D., Yoshino H., Ueda T., Manabe A., Tanaka R., Ikeda Y. CD34 expression on long-term repopulating hematopoietic stem cells changes during developmental stages. Blood. 2001 Jan 15;97(2):419–425. doi: 10.1182/blood.v97.2.419. [DOI] [PubMed] [Google Scholar]
  15. McGee Glenn, Caplan Arthur. The ethics and politics of small sacrifices in stem cell research. Kennedy Inst Ethics J. 1999 Jun;9(2):151–158. doi: 10.1353/ken.1999.0012. [DOI] [PubMed] [Google Scholar]
  16. Meyer J. R. Human embryonic stem cells and respect for life. J Med Ethics. 2000 Jun;26(3):166–170. doi: 10.1136/jme.26.3.166. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Mezey Eva, Key Sharon, Vogelsang Georgia, Szalayova Ildiko, Lange G. David, Crain Barbara. Transplanted bone marrow generates new neurons in human brains. Proc Natl Acad Sci U S A. 2003 Jan 21;100(3):1364–1369. doi: 10.1073/pnas.0336479100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Morshead Cindi M., Benveniste Patricia, Iscove Norman N., van der Kooy Derek. Hematopoietic competence is a rare property of neural stem cells that may depend on genetic and epigenetic alterations. Nat Med. 2002 Mar;8(3):268–273. doi: 10.1038/nm0302-268. [DOI] [PubMed] [Google Scholar]
  19. Okarma T. B. Human primordial stem cells. Hastings Cent Rep. 1999 Mar-Apr;29(2):30–30. [PubMed] [Google Scholar]
  20. Pera M. F. Scientific considerations relating to the ethics of the use of human embryonic stem cells in research and medicine. Reprod Fertil Dev. 2001;13(1):23–29. doi: 10.1071/rd00077. [DOI] [PubMed] [Google Scholar]
  21. Schuldiner M., Yanuka O., Itskovitz-Eldor J., Melton D. A., Benvenisty N. Effects of eight growth factors on the differentiation of cells derived from human embryonic stem cells. Proc Natl Acad Sci U S A. 2000 Oct 10;97(21):11307–11312. doi: 10.1073/pnas.97.21.11307. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Surani M. A. Reprogramming of genome function through epigenetic inheritance. Nature. 2001 Nov 1;414(6859):122–128. doi: 10.1038/35102186. [DOI] [PubMed] [Google Scholar]
  23. Terada Naohiro, Hamazaki Takashi, Oka Masahiro, Hoki Masanori, Mastalerz Diana M., Nakano Yuka, Meyer Edwin M., Morel Laurence, Petersen Bryon E., Scott Edward W. Bone marrow cells adopt the phenotype of other cells by spontaneous cell fusion. Nature. 2002 Mar 13;416(6880):542–545. doi: 10.1038/nature730. [DOI] [PubMed] [Google Scholar]
  24. Vastag B. Many say adult stem cell reports overplayed. JAMA. 2001 Jul 18;286(3):293–293. [PubMed] [Google Scholar]
  25. Vogel G. Can old cells learn new tricks? Science. 2000 Feb 25;287(5457):1418–1419. doi: 10.1126/science.287.5457.1418. [DOI] [PubMed] [Google Scholar]
  26. Vogel G. Cell biology. Stem cells: new excitement, persistent questions. Science. 2000 Dec 1;290(5497):1672–1674. doi: 10.1126/science.290.5497.1672. [DOI] [PubMed] [Google Scholar]
  27. Vogel Gretchen. Stem cell research. Rat brains respond to embryonic stem cells. Science. 2002 Jan 11;295(5553):254–255. doi: 10.1126/science.295.5553.254b. [DOI] [PubMed] [Google Scholar]
  28. Watt F. M., Hogan B. L. Out of Eden: stem cells and their niches. Science. 2000 Feb 25;287(5457):1427–1430. doi: 10.1126/science.287.5457.1427. [DOI] [PubMed] [Google Scholar]
  29. Winston R. Embryonic stem cell research. The case for... Nat Med. 2001 Apr;7(4):396–397. doi: 10.1038/86442. [DOI] [PubMed] [Google Scholar]
  30. Wu Ping, Tarasenko Yevgeniya I., Gu Yanping, Huang Li-Yen M., Coggeshall Richard E., Yu Yongjia. Region-specific generation of cholinergic neurons from fetal human neural stem cells grafted in adult rat. Nat Neurosci. 2002 Dec;5(12):1271–1278. doi: 10.1038/nn974. [DOI] [PubMed] [Google Scholar]
  31. Ying Qi-Long, Nichols Jennifer, Evans Edward P., Smith Austin G. Changing potency by spontaneous fusion. Nature. 2002 Mar 13;416(6880):545–548. doi: 10.1038/nature729. [DOI] [PubMed] [Google Scholar]
  32. Zhao Li-Ru, Duan Wei-Ming, Reyes Morayma, Keene C. Dirk, Verfaillie Catherine M., Low Walter C. Human bone marrow stem cells exhibit neural phenotypes and ameliorate neurological deficits after grafting into the ischemic brain of rats. Exp Neurol. 2002 Mar;174(1):11–20. doi: 10.1006/exnr.2001.7853. [DOI] [PubMed] [Google Scholar]
  33. Zuk P. A., Zhu M., Mizuno H., Huang J., Futrell J. W., Katz A. J., Benhaim P., Lorenz H. P., Hedrick M. H. Multilineage cells from human adipose tissue: implications for cell-based therapies. Tissue Eng. 2001 Apr;7(2):211–228. doi: 10.1089/107632701300062859. [DOI] [PubMed] [Google Scholar]
  34. van der Kooy D., Weiss S. Why stem cells? Science. 2000 Feb 25;287(5457):1439–1441. doi: 10.1126/science.287.5457.1439. [DOI] [PubMed] [Google Scholar]

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