Extracellular vesicles support increased expansion of mesenchymal stromal cells on fetal membrane-derived decellularized extracellular matrix.

Decidual mesenchymal stromal cells (DMSC) were the source of extracellular vesicles (DMSC_EV). The xCELLigence real-time cell growth assay revealed increasing concentrations of EVs decreased DMSC attachment in the early growth phase but stimulated DMSC proliferation at day 7 when grown on tissue culture plastic (TCP). DMSC attachment and proliferation varied depending on the growth surface and DMSC_EV supplementation. DMSC attachment increased on decellularized and solubilized amniotic (s-dAM) whether or not EVs were added. Only Matrigel substrate increased DMSC attachment with added EVs. The addition of EVs increased DMSC proliferation only on the s-dAM substrate. DMSCs were more motile on s-dAM and decellularized and solubilized chorionic (s-dCM) membranes following EV addition. The osteogenic potential of DMSCs was improved on s-dAM substrates when supplanted with EVs. Finally, the levels of reactive oxygen species in DMSCs varied depending on the substrate but not on added EVs. We show that the addition of in vitro EVs isolated from the source being expanded (i.e., DMSCs) and the presence of ECM improve DMSC behaviours during ex vivo expansion. The inclusion of two key components of the MSC niche, EVs and ECM, benefitted the ex vivo expansion of MSCs. Added in vitro EVs increased the proliferation of DMSCs when grown on s-dAM but not on s-dCM, whereas they improved DMSC mobility on both surfaces. Testing different ECMs could be used to promote specific desired characteristics of DMSCs, and different combinations of EVs and ECM may enhance desirable MSC characteristics for specific therapeutic settings.