A new method for the rapid and long term growth of human neural precursor cells

A reliable source of human neural tissue would be of immense practical valu e to both neuroscientists and clinical neural transplantation trials. In th is study, human precursor cells were isolated from the developing human cor tex and, in the presence of both epidermal and fibroblast growth factor-2, grew in culture as sphere shaped clusters. Using traditional passaging tech niques and culture mediums the rate of growth was extremely slow, and only a 12-fold expansion in total cell number could be achieved. However, when i ntact spheres were sectioned into quarters, rather than mechanically dissoc iated, cell-cell contacts were maintained and cellular trauma minimised whi ch permitted the rapid and continual growth of each individual quarter. Usi ng this method we have achieved a 1.5 million-fold increase in precursor ce ll number over a period of less than 200 days. Upon differentiation by expo sure to a substrate, cells migrated out from the spheres and formed a monol ayer of astrocytes and neurons. No oligodendrocytes were found to develop f rom these human neural precursor cells at late passages when whole spheres were differentiated. This simple and novel culture method allows the rapid expansion of large numbers of non-transformed human neural precursor cells which may be of use in drug discovery, ex vivo gene therapy and clinical ne ural transplantation. (C) 1998 Elsevier Science B.V. All rights reserved.