StemCells' GS2-M cell culture media formulation enhances pluripotency of human ES, iPS cells

StemCells, Inc. (Nasdaq:STEM) announced today that newly published independent research demonstrates that its GS2-M™ cell culture media formulation enhances the pluripotency of human embryonic stem (ES) and induced pluripotent stem (iPS) cells. The Company's GS2-M medium has already been shown to enable the derivation and long-term maintenance of mouse iPS cells. With this new application of GS2-M, researchers may now be able to significantly advance human pluripotent stem cell research.

Specifically, researchers at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts have recently succeeded in pushing human stem cells back to a more naive state similar to that of mouse ES cells by using a GS2-M based culture media in combination with specific compounds. Conventional human ES and iPS cells are considered to be more mature than mouse ES cells or 'primed' for differentiation into other cell types, which makes them more difficult to manipulate and study. Consequently, stem cell researchers often use mouse ES cells because they are easy to access, work with and provide a means to study human disease states such as cancer, diabetes and dementia through precise gene manipulation. However, mouse and human pluripotent cells have significant biological differences due largely to the different media in which they are cultured.  As a result, it is often not possible to reproduce results in human cells as those achieved in mouse cells.  With this discovery by the Whitehead Institute, researchers can now achieve and maintain a naive state with human ES and iPS cells approaching the flexibility of mouse ES cells.

"We congratulate the Whitehead Institute researchers on this important discovery, and are pleased to announce this expanded application for our GS2-M product," said Stewart Craig, Senior Vice President, Development and Operations at StemCells, Inc. "With the addition of two simple molecules to our GS2-M media formulation, researchers can now achieve an 'apples to apples' comparison when exploring the biology of naive human and mouse pluripotent stem cells.  This is particularly important for analyzing in vitro data between mouse and human cells and for the study of certain diseases, a comparison previously not possible due to the differences in human and mouse pluripotent cells resulting from methods used for their culture."

GS2-M is a completely defined, serum-free media containing selective small molecule inhibitors that block differentiation-inducing signals and promote cell survival and expansion. GS2-M has been shown to:

• Efficiently convert human primed ES or iPS cells into fully pluripotent stem cells in the presence of forskolin and leukemia inhibitory factor (LIF)
• Efficiently convert partially reprogrammed, or 'pre-iPS', mouse cells into fully pluripotent stem cells in the presence of LIF
• Maintain naive human and mouse ES and IPS cells in a definitive pluripotent 'ground state' in long-term culture

The GS2-M media formulation is based on the '2i' technology developed by prominent academic researchers in the United Kingdom, and exclusively licensed to StemCells, Inc.