Influence of tissue source on the therapeutic potential of mesenchymal stromal cells

Advanced therapy medicinal products (ATMPs) offer revolutionary new prospects for the treatment of conditions of unmet medical need. Among them, Mesenchymal Stromal Cells (MSCs) have emerged as promising candidates for cell-based regenerative medical therapies. Currently, several early phase clinical trials have been completed and many are ongoing to explore MSC safety and efficacy in a wide range of nephropathologies. Kidney diseases are a current major health concern with an increasing global prevalence. The current standards of care focus on supportive treatments, emphasizing the need to develop novel and efficient therapies to delay or halt disease progression. However, before these therapies can be routinely used in patients, there are still hurdles to overcome. One of the current roadblocks relates to the lack of standardization of manufacturing protocols. Studies have shown that cell culture processing variables can have significant effects on MSC phenotype and functionality. In addition, MSCs can be isolated from various sources and there is now a growing body of literature highlighting unique and intrinsic properties according to the tissue origin and donor characteristics. Having an optimal, well-designed scale-up strategy for MSC manufacturing is critical to ensure product quality. In this thesis, we first sought to develop a protocol to expand the most clinically used MSC populations – adipose, bone marrow, and umbilical cord – in a multicentre study to compare the properties of the cells emanating from these three sources when cultured in a de-centralised manufacturing approach. By implementing a harmonised expansion workflow, we identified unique growth patterns and differentiation potential that followed comparable trends among centres. We harmonized our culture expansion conditions including the use of a single source of foetal bovine serum (FBS) in order to minimize culture condition-induced alterations in cell biology. Due to the inherent heterogeneity within the MSC-field, in terms of both culture conditions and source material, the development of strategies to select the optimal ‘source’ for a particular clinical condition would facilitate successful clinical translation. For this, the identification of features beyond basic cell characteristics are in need of further investigation. In this thesis, we focused on assessing the ability of MSCs from different tissue origin to support angiogenesis, essential during tissue regeneration. Bone marrow derived MSCs and their secretome showed significantly enhanced abilities to promote tubulogenesis and endothelial cell migration in vitro, partially due to a superior secretion of angiogenic cytokines such as vascular endothelial growth factor (VEGF). Additionally, the central metabolism is a critical driver of many cellular functions and has been shown to vary and alter the therapeutic benefit of MSCs undergoing large-expansion procedures. The comparison of metabolic characteristics and cellular fitness between MSC populations revealed a robust and stem cell-like phenotype in umbilical cord derived MSCs that conferred them higher abilities to withstand challenging microenvironments. Finally, we investigated the therapeutic efficacy of MSC-derived bioproducts, namely their secretome and extracellular vesicles, to restore metabolic disturbances in an in vitro model of renal ischaemia/reperfusion injury (IRI). Collectively, results to date emphasize the heterogeneity of MSCs in their nature and mechanism of action. The development of culture conditions appropriately designed to support cell expansion while enhancing therapeutic potential will allow for the elucidation of their unique regenerative properties, facilitating the development of tailored and efficient therapies for a given medical condition.

Publisher

NUI Galway

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Attribution-NonCommercial-NoDerivs 3.0 Ireland
CC BY-NC-ND 3.0 IE

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University of Galway Theses (PhD Theses)