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A new technique for human embryonic stem cell (hESC) culture that reduces the use of animal-derived compounds, making them potentially safer and more reliable for biomedical applications is reported in the March issue of Nature Methods.
hESCs have the potential to form any other cell type in the body, a process called differentiation; but this flexibility comes at a price, and these cells are notoriously difficult to cultivate so that they maintain their potential. Current techniques involve growing them atop mouse-derived "feeder" cells, or in an environment that has been saturated with compounds produced by such cells. This is problematic, as it raises the risk of exposing hESCs to animal-borne pathogens. Additionally, recently published findings (Martin et al., Nature Medicine 11, 228-232; 2005) demonstrated that hESCs could take up and present a highly immunoreactive mouse cell-derived molecule during culture, raising a serious risk of host immune response after transplantation. An animal product-free stem cell culture system would be ideal, and although this goal is still over the horizon, James Thomson, Ren-He Xu and their colleagues present an important step in this direction, demonstrating successful hESC culture without feeder cell contribution. The team identified a factor responsible for premature differentiation of hESCs, and found that other compounds produced by mouse feeder cells appear to block the action of this particular factor. By culturing hESCs in medium containing these specific compounds, their developmental potential can be preserved without feeder cells, eliminating a major source of potential animal-derived contaminants. Although this system still utilizes some animal-derived additives for culture, it could represent a strong step in the right direction. In an accompanying News & Views article, stem cell researcher Martin Pera comments on the Thomson group's work and its potential contribution to the field of hESC research. Author contact: Ren-He Xu
WiCell Research Institute)
Tel: +1 608 265 9312
E-mail: rxu@wicell.org James A. Thomson
University of Wisconsin-Madison
Tel: +1 608 263 3585
E-mail: thomson@primate.wisc.edu Martin F. Pera
Monash Institute of Medical Research
Tel: +61 9594 7318
E-mail: martin.pera@med.monash.edu.au Also available online. (C) Nature Methods press release.
Message posted by: Trevor M. D'Souza
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