Stem Cell Safety
It is an unfortunate reality that the therapies often holding the most potential also carry numerous queries regarding their safety. Stem cells are one such topic of concern – their potential to treat disease is exciting but their safety concerns have kept them from being approved for many treatments, despite their initial indications of promising success.
Do the Stem Cells Act as Intended?
A crucial element in assessing stem cell safety is the question: do the cells act as they are intended once transplanted? The unpredictable reality can be that once implanted, stem cells may begin to uncontrollably divide and differentiate into cancer cells, leading to tumor growth. Scientists test the therapies by inducing conditions in laboratory animals, such as a diabetic condition in mice. Laboratory animal models are still, however, far from being perfect predictors of how stem cells will behave once transplanted in humans. The fear of unregulated growth leading to cancerous tumor development is a frightening concept that must be solved before stem cells can reach mainstream status for use to treat the full range of diseases they show potential to help.
Stem Cell Contamination
Stem cell lines used for research are not always ‘pure’ because their exposure to other animal cells to maintain viability results in contamination. Many animal cells contain microscopic microbes and diseases that are undetectable and contaminate human embryonic stem cells used for research. Older stem cell lines that are approved for use are also not as ‘fresh’ and may therefore develop genetic dysfunctions due to their age. As they proliferate, these genetic abnormalities then put the cells at risk for developing into a tumour. Used in a stem cell transplant, the ramifications could potentially be very dangerous.
Regardless of the stem cell source – whether embryonic, adult or cord blood – screening is important to ensure compatibility to the recipient and the specific medical condition being treated. If stem cells were derived from someone with a strong familial history of cardiovascular disease, for example, they would perhaps not be well suited to a recipient who required cardiac heart cells for a damaged heart. In addition, gene analysis and testing for infectious diseases is mandatory to prevent transmission to the recipient.
Biological Activity of Stem Cells
Before stem cells are transplanted, they must possess sufficient biological activity to ensure that they will be successful once implanted. This basically means that scientists need to be certain that the stem cells are healthy and functioning before going through the arduous process of transplantation, often for a person who is extremely ill and can’t afford the time-consuming procedure of a stem cell transplant that simply won’t work.
Clearly, stem cell safety must be scrutinised and assessed throughout the entire treatment or research process. Guidelines and strategies must also be developed to ensure that every aspect of stem cell use – from identification and isolation of stem cells to stem cell transplant – is stringently coordinated. Stem cell lines must be adequately screened for disease and the sources must be examined in depth. If doctors and scientists can establish safe protocols for stem cell use, everyone can benefit from the full potential of the remarkable and possibly life-saving stem cell therapies.
Where can I get more information on stem cells?
For a more detailed discussion of stem cells, see the NIH’s Stem Cell Reports. Check the Frequently Asked Questions page for quick answers to specific queries. The navigation table at right can connect you to the information you need.
The following websites, which are not part of the NIH Stem Cell Information site, also contain information about stem cells. The NIH is not responsible for the content of these sites.
Stem cell information for the public from the International Society for Stem Cell Research (ISSCR).
Medline Plus is a consumer health database that includes news, health resources, clinical trials, and more
A United Kingdom-based resource for the general public that discusses the use of stem cells in medical treatments and therapies.
A commercial, online newsletter that features stories about stem cells of all types.
Medical and Ethical Guidelines for Human Experimentation:
The following codes should be considered for human experimentation:
Stem Cell Links
The following links are provided for your information:
- Stem Cell Information and Background
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- Stem Cell-related Organizations (US)
- Stem Cell Research Foundation
- Student Society for Stem Cell Research
- Stem Cell Action Network (SCAN) A grassroots
advocacy organization whose goal is empowering
voters with information about stem cell research to
enable them to choose candidates and support
public policy that is in their best interest.
- International Society for Experimental Hematology
- International Society for Stem Cell Research
- International Stem Cell-related Organizations
- EuroStemCell (European Consortium for
Stem Cell Research): Brings together
leading investigators from across Europe to
compare the basic properties of
stem cells and to evaluate their therapeutic
potential. The project involves eleven
academic institutes and three small
and medium-sized enterprises (SMEs)
from eight European countries. The researchers
have expertise in transgenesis, stem cell biology,
developmental biology, tissue repair, in vivo
disease models and clinical cell transplantation.
- Cambridge (UK) Stem Cell Institute
- Institute for Stem Cell Research, University of
- Lund Stem Cell Center (Sweden)
- Karolinska Institute (Sweden)
- Danish Stem Cell Research Center (Denmark)
- National Center for Stem Cell Research
(Norway): Established in 2003, the NCS is
a national network of research groups
working with stem cells in Norway.