An Overview of Mesenchymal Stem Cell Heterogeneity and Concentration

Abstract

Mesenchymal stem cells (MSCs) are of great interest in cell therapies due to the immunomodulatory and other effects they have after autologous or allogeneic transplantation. In most clinical applications, a high number of MSCs is required; therefore, the isolated MSC population must be expanded in the cell culture until the desired number is reached. Analysing freshly isolated MSCs is challenging due to their rareness and heterogeneity, which is noticeable among donors, tissues, and cell subpopulations. Although the phenotype of MSCs in tissue can differ from those of cultured cells, phenotyping and counting are usually performed only after MSC proliferation. As MSC applicability is a developing and growing field, there is a need to implement phenotyping and counting methods for freshly isolated MSCs, especially in new one-step procedures where isolated cells are implanted immediately without cell culturing. Only by analysing harvested cells can we correctly evaluate such studies. This review describes multilevel heterogeneity and concentrations of MSCs and different strategies for phenotype determination and enumeration of freshly isolated MSCs.

Current Methods for Analysing Mesenchymal Stem Cell-Derived Extracellular Vesicles

“…Generally, beads are also used to capture either all particles in the sample, regardless of the composition, or specific particles based on bead-conjugated antibodies [ 12 ]. EVs are then usually stained for MSC surface markers CD73, CD90 [ 22 , 32 ] and CD105 [ 33 , 34 ], along with tetraspanin markers CD9, CD63, and CD81 binding to different fluorescent dyes [ 17 , 22 , 32 , 33 ]. The presence of hematopoietic markers CD45, CD44 and CD29, the α4 and α5 integrins and human leukocyte antigen (HLA) is also analysed [ 35 ].…”

Regulation of the Nrf2/HO-1 axis by mesenchymal stem cells-derived extracellular vesicles: implications for disease treatment

“…Addressing these challenges requires innovative approaches in EV isolation, characterization, and functional assessment, along with a deeper exploration of EV biogenesis pathways to unravel the origins of heterogeneity. Ultimately, deciphering the intricacies of EV heterogeneity holds the key to unlocking their full therapeutic potential in regenerative medicine ( van de Wakker et al, 2023 ; Maličev and Jazbec, 2024 ). Scalability in EV production is a critical aspect for translating research findings into clinical applications.…”