Advanced therapies (ATMPs) are revolutionizing the field of regenerative medicine, thanks to their efficacy in treating the underlying cause of diseases and unmet medical needs, by repairing, replacing or regenerating organs, tissues, cells, genes and metabolic processes of the body.
Bioprocess Engineering for Mesenchymal Stromal Cell Production
Dr. Víctor García Gragera defended his thesis at IQS, in which he developed and improved the technology for the production of mesenchymal cells in closed stirred-tank bioreactors, and promoted their transfer towards an allogeneic clinical application, in a context of good manufacturing practices.
Human mesenchymal stromal cells derived from Wharton’s jelly of the umbilical cord (WJ-MSCs) are emerging as a material with great potential for the treatment of musculoskeletal disorders, immune disorders and other degenerative diseases. These cells are traditionally produced using efficient culture systems for single-dose treatments, but this approach is not suitable for larger-scale manufacturing. Their clinical translation requires robust, scalable, automated bioprocesses aligned with good manufacturing practices (GMP), capable of producing the high cell quantities required for therapeutic use.
To respond to these needs, Dr. Víctor García Gragera has carried out his doctoral thesis at IQS under the title Bioprocess Engineering and Microcarrier Technology for Mesenchymal Stromal Cell Production, directed by Dr. Martí Lecina Veciana, from the Materials Engineering Group – GEMAT of IQS, and by Dr. Joaquim Vives, head of the BACT (Bioprocessing for Advanced Cell Therapies) research group of the BST – Banc de Sang i Teixits.
The objective of the thesis was to develop and improve the technology for the production of mesenchymal cells (MSCs) in closed stirred-tank bioreactors (STRs) and favor their transfer towards an allogeneic clinical application, always keeping in mind the translation of the technology in a context of good manufacturing practices.
Manufacturing of MSCs in closed bioreactors
First, Dr. García Gragera has developed a WJ-MSC expansion process free of serum and non-human components (XSF, for xeno- and serum-free), using stirred-tank bioreactors (STRs) and ‘microcarriers’ (MCs), with the aim of facilitating the transition from SCM to XSFM. Thanks to this first approach, it was possible to identify various limitations of the XSF process compared to the bioprocess using serum, and the cell metabolism and growth were characterized, establishing colonization on day 1 as a critical process parameter
Next, a series of experiments were carried out that allowed establishing a manufacturing method for pH-dependent soluble dextran MCs. The validation of their degradability and sterilization using gamma (γ) radiation gave very good results, making it possible to identify a design space.
Process optimization for its transfer
Homogeneity in the bioreactors turned out to be a susceptible factor for introducing under- or overestimations in monitoring and, therefore, limiting the automation of the bioprocess. To study the variables affecting mixing in the bioreactor, computational fluid dynamics (CFD) simulations were carried out with the aim of, on the one hand, confirming the benefits of the modifications introduced in the vessel geometry and mixing, and also quantifying the impact of possible changes in particle re-suspension and system homogeneity. This part of the research was done in collaboration with Dr. Joaquín Menacho and Dr. Ibuki Kusano from the Industrial Engineering Department of IQS.
Finally, all the obtained data were integrated to improve and optimize the bioprocess for obtaining MCs. Comparisons between 2D and STR cultures allowed describing the differences between the media used and their possible limitations. A deeper understanding of the colonization of WJ-MSCs on MCs facilitated the definition of an optimized protocol for their production in these bioreactors. Likewise, new insights were gained regarding the impact of dissolved oxygen, albumin, and MC loading on the process.
In conclusion, the expansion platform designed in this thesis, which is closed, scalable and free of xeno and non-human components (XSF), has improved the manufacturing productivity of WJ-MSCs, achieving a 60% increase in colonization on day 1, while minimizing hydrodynamic stress and ensuring a homogeneous mixture. In a comprehensive work of bioprocess engineering and materials science at the service of advanced therapies, Dr. García Gragera’s thesis thus opens the door to making WJ-MSC-based therapies more accessible and serves as a starting point for other bioprocesses with adherent cells.
“Understanding and controlling the bioprocess for the expansion of mesenchymal cells will allow us to move from the laboratory to the clinic successfully, ensuring a sufficient dose and quality for patients with complex pathologies,” highlights Dr. Joaquim Vives.
Related published scientific papers
Victor Garcia-Gragera et al, Identification of critical process parameters for expansion of clinical grade human Wharton’s jelly-derived mesenchymal stromal cells in stirred-tank bioreactors, Biotechnology Journal, 2024, 19, Issue 2, 2300381
This thesis received a grant from the AGAUR-FI predoctoral programme, Joan Oró grants from the Department of Research and Universities of the Generalitat de Catalunya and the European Social Plus Fund.
This research is part of the CERTERA Consortium for the development and expansion of national capabilities in the field of advanced therapies
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