Previous methods for culturing human embryonic stem cells have required
either fibroblast feeder cells or a medium which has been exposed to
fibroblast feeder cells in order to maintain the stem cells in an
undifferentiated state. It has now been found that if high levels of
fibroblast growth factor are used in a medium with gamma amino butyric
acid, pipecholic acid, lithium and lipids, the stem cells will remain
undifferentiated indefinitely through multiple passages, even without
feeder cells or conditioned medium. A humanized matrix of human proteins
can be used as a basement matrix to culture the cells. New lines of human
embryonic stem cells made using these culture conditions, the medium and
the matrix, will never have been exposed to animal cells, animal
products, feeder cells or conditioned medium.