An Optimized Method for Obtaining Clinical-grade Specific Cell Subpopulations from Human Umbilical Cord-derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are heterogeneous populations with broad application prospects in cell therapy, and using specific subpopulations of MSCs can enhance their particular capability under certain conditions and achieve better therapeutic effects. However, no studies have reported how to obtain high-quality specific MSC subpopulations in vitro culture. Here, for the first time, we established a general operation process for obtaining high-quality clinical-grade cell subpopulations from human umbilical cord MSCs (hUC-MSCs) based on particular markers. We used the MSC-CD106 subpopulations, whose biological function has been well documented, as an example to explore and optimize the crucial links of primary preparation, pre-treatment, antibody incubation, flow sorting, quality and function test. After comprehensively evaluating the quality and function of the acquired MSC-CD106 subpopulations, including in vitro cell viability, apoptosis, proliferation, marker stability, adhesion ability, migration ability, tubule formation ability, immunomodulatory function and in vivo wound healing ability and proangiogenic activity, we defined an important pre-treatment scheme which might effectively improve the therapeutic efficiency of MSC-CD106 subpopulations in two critical clinical application scenarios-direct injection after cell sorting and post-culture injection into bodies. Based on the above, we tried to establish a general five-step operation procedure for acquiring high-quality clinical-grade MSC subpopulations based on specific markers, which cannot only improve their enrichment efficiency and the reliability of preclinical studies, but also provide valuable methodological guidance for the rapid clinical transformation of specific MSC subpopulations.