Premature ageing is an important feature in several placental pathologies.
A recent study revealed that placental tissue exhibited signs of advanced ageing in the period between early-term (37 0/7 – 38 6/7 wks gestation) and late/post-term (41 0/7 wks gestation and beyond) periods of pregnancy. Mesenchymal stem/stromal cells (MSCs) play a significant role in placental development. This study focused on MSCs from the maternal component of the placenta; the decidua basalis (DMSCs). Late/post-term DMSCs, when compared to early-term DMSCs, show increased levels of cell death and higher expression of ageing markers (Khanabdali, 2016). These results are consistent with advanced ageing having an association with adverse effects on the mother’s and baby’s health. The paracrine effects of MSCs are mediated by secreted vesicles called exosomes and so, the objective of this study was to isolate and characterize exosomes from early-term and late/post-term DMSCs and compare their functional properties.
DMSCs were cultured and growth medium containing exosomes was obtained. Exosomes were isolated using three methods; ultracentrifugation, precipitation and magnetic separation and visualized using electron microscopy. Yield and purity were compared using protein assays and Nanosight analysis respectively. The effect of early-term and late/post-term DMSC exosomes on proliferation and attachment of DMSCs was determined by the xCELLigence real-time functional assay.
Precipitation gave the highest yield of exosomes (26.09±3.46µg/ml), whereas ultracentrifugation gave highest purity (4.6±1.90 x 1010 exosome-sized particles/ml) (n=5). Results showed that early-term DMSC exosomes, significantly increased attachment of DMSCs to tissue culture plastic and also their subsequent proliferation and survival (n=6, p<0.05). In contrast, late/post-term DMSC exosomes did not aid in the proliferation of DMSCs.
This study provides first evidence that exosomes from early-term and late/post-term DMSCs are functionally different, and that early-term exosomes can reduce or reverse the age-associated decline of cellular functions found in late/post-term DMSCs.