Aging and cell expansion enhance microRNA diversity in small extracellular vesicles produced from human adipose-derived stem cells

Adipose-derived stem cells (ASCs) and their small extracellular vesicles (sEVs) hold significant potential for regenerative medicine due to their tissue repair capabilities. The microRNA (miRNA) content in sEVs varies depending on ASC status; however, the effects of aging and cell passage on miRNA profiles remain unclear. In this study, we examined the effects of donor age and cell expansion on ASC characteristics and transcriptome using ASCs obtained from three young and three old donors. Cell expansion significantly impaired stem cell properties, notably reducing proliferation and differentiation capacities. In contrast, donor age had minimal effects on ASCs. RNA sequencing (RNA-seq) revealed differences in gene expression related to stemness, phagocytosis, and metabolic processes influenced by cell expansion. To investigate miRNA variability, we performed small RNA-seq on sEVs collected from ASCs of all six donors. The miRNA profiles were influenced by donor age and cell passage. Interestingly, functional enrichment analysis indicated that advanced donor age and increased cell passage may enhance the production of miRNAs associated with organ development through various pathways. These findings suggest that donor age and cell expansion differentially influence ASC characteristics and sEV miRNA content, highlighting the need for disease-specific conditioning of ASCs to optimize the therapeutic effects of sEVs in clinical applications.