Abstract
The promise of human embryonic stem cells (hESCs) to provide an unlimited supply of cells for cell therapy depends on the availability of a controllable bioprocess for their expansion and differentiation. We describe here a robust and well-defined scale up platform for human embryoid body (EB) formation, propagation, and differentiation. The efficacy of the dynamic process as compared to the static cultivation in Petri dishes was analyzed. Our optimized conditions include specific bioreactor and impeller type, seeding and propagation parameters, and scale up. Quantitative analyses of viable cell concentrations, apoptosis percentages, and EB yield revealed 6.7-fold enhancement in the generation of hESC-derived cells after 10 cultivation days. Other metabolic indices such as glucose consumption, lactic acid production and pH all pointed to efficient cell expansion in the dynamic cultures. The hydrodynamic conditions during seeding and cultivation were found to be crucial for the EB formation and propagation. The EBs’ prearrangement in the static system and EB cultivation in the Glass Ball Impeller spinner flask resulted in high EB yield, a round homogenous shape, and the fastest growth rate. The appearance of representative genes of the three germ layers as well as primitive neuronal tube organization and blood vessel formation indicated that the initial developmental events in the human EBs are not interfered by the dynamic system. Furthermore, well developed endothelial networks and contracting EBs with functional cardiac muscle were also obtained after two cultivation weeks. Collectively, our study defines the technological platform for the controlled large-scale generation of hESC-derived cells for clinical and industrial applications.