Bioreactor Expansion of Human Neural Precursor Cells in Serum-Free Media Retains Neurogenic Potential

Human neural precursor cells (hNPCs), har- vested from somatic tissue and grown in vitro, may serve as a source of cells for cell replacement strategies aimed at treating neurodegenerative disorders such as Parkinson's disease (PD), Huntington's disease (HD), and intractable spinal cord pain. A crucial element in a robust clinical production method for hNPCs is a serum-free growth medium that can support the rapid expansion of cells while retaining their multipotency. Here, we report the develop- ment of a cell growth medium (PPRF-h2) for the expansion of hNPCs, achieving an overall cell-fold expansion of 10 13 over a period of 140 days in stationary culture which is significantly greater than other literature results. More importantly, hNPC expansion could be scaled-up from stationary culture to suspension bioreactors using this med- ium. Serial subculturing of the cells in suspension bioreac- tors resulted in an overall cell-fold expansion of 7.8 � 10 13 after 140 days. These expanded cells maintained their multi- potency including the capacity to generate large numbers of neurons (about 60%). In view of our previous studies regarding successful transplantation of the bioreactor- expanded hNPCs in animal models of neurological disor- ders, these results have demonstrated that PPRF-h2 (con- taining dehydroepiandrosterone, basic fibroblast growth factor and human leukemia inhibitory factor) can success- fully facilitate the production of large quantities of hNPCs with potential to be used in the treatment of neurodegen- erative disorders. Biotechnol. Bioeng. 2010;105: 823-833. 2009 Wiley Periodicals, Inc.