The goal of this project is to develop compact mathematical model to describe the most important aspects of glucose, amino acids and oxygen metabolism in hiPSc 3D expansion process by taking into account stem cell aggregation phenomenon and heterogeneity of the culture. Based on the developed mathematical model, some optimization procedures will be carried out to identify the rational culture parameters for the cell expansion process, such as feeding modes, oxygen tension and cell aggregation control. The improved culture cultivation parameters should allow achieving higher concentration of undifferentiated (hiPSc) cells at the end of cultivation without significant differentiation of stem cells. Project partner: Laboratory of Bioprocess Systems Engineering, Osaka University (Japan).
Intergovernmental programme administrated by Research Council of Lithuania: Lithuania –Japan
During the project, analysis of 3D mixing processes of bioreactor-scale expansion of human induced pluripotent stem cells has been performed. The pluripotent stem cell expansion methods that are the most perspective for real practical biomedical applications have been identified. The key factors, which affect the rates of expansion and differentiation, have been determined. The state variables that shall be used in mathematical models for optimization and control of expansion processes have been identified. By means of iterative modelling procedure, the rational structure of mathematical model for pluripotent stem cell expansion process has been identified. The key kinetic rate expressions of the main process bioreactions have been selected. Using experimental data available in the literature and supplied by the research partner, the parameters of the mathematical model have been identified and evaluation of modelling quality has been performed. By applying model-based process optimization procedures, two-step process optimization strategy has been proposed. During the first step, using a simplified model, the optimal cell aggregate disruption time moments have been calculated that enable maximization of stem cell number at the end of expansion process. A profile of dissolved oxygen concentration, which shall be maintained during the expansion process to avoid more significant cell differentiation, has been calculated. An automatic control system for maintenance of such profile has been proposed. During the second step of optimization, using full process mathematical model, the optimal time profiles of glucose and glutamine concentrations as well as their feeding rates have been determined. The performed simulation tests have revealed that the optimized stem cell expansion technologies yield in 2-3 times higher cell numbers at the end of expansion processes as compared to recently applied cell expansion modes. Based on the optimization results, practical recommendations have been provided to the project partners how the obtained results could be implemented in real stem cell expansion processes.
Period of project implementation: 2015-10-01 - 2017-09-30
Project coordinator: Kaunas University of Technology
Project partners: Osaka University