Geron publicates studies about growth of human embryonic stem cells in serum-free medium
Geron Corporation announced the publication of studies which demonstrate that human embryonic stem cells (hESCs) can be propagated in culture using defined growth factors without the need for feeder cells or media conditioned by feeder cells. The results represent a major step forward in the development of scalable systems to culture hESCs for the production of therapeutic cell products.
hESCs have distinct advantages over other types of stem cells in that they have both unlimited growth capacity and the ability to differentiate into cell populations found in all tissues of the body. Initially, hESCs were grown in direct contact with mouse feeder cells which supplied components that maintained the cells' proliferative capacity. In later studies, Geron demonstrated that hESCs could be grown without the need for direct contact with feeder cells, provided that they were supplied with medium that had been previously conditioned by contact with either mouse or human cells. In the studies reported in the March issue of Stem Cells, Geron scientists now show that hESCs can be propagated in a serum-free medium containing specific defined growth factors, without the need for either feeder cells or conditioned medium. Only a single growth factor, basic fibroblast growth factor (bFGF), is required in this system. This new method maintained stable proliferation of two hESC cell lines tested for at least 11-15 weeks. In addition, the undifferentiated hESCs retained expression of characteristic undifferentiated cell markers, including telomerase, while maintaining their potential to differentiate into cells representing all the major cell lineages of the body.
A similar development has recently been reported in the March issue of Nature Methods by Dr. James Thomson's laboratory at the University of Wisconsin, Madison. In that study, hESCs were successfully cultured in the same serum-free medium using bFGF together with another factor, noggin, also without feeder cells.
The technology of feeder-free growth of hESCs is broadly covered by U.S. Patent No. 6,800,480 issued to Geron in 2004. The elimination of feeder cells of any kind from the culture process by which hESCs are grown is important not only for the large scale production of hESC-based products, but it also eliminates the risk of contamination of the therapeutic cell populations by infectious agents or other components derived from the feeder cells.
Other news from the department science
