Study Design
Samples of amniotic fluid (AF) collected at >37 weeks of
gestation (North of Scotland Research Ethics Committee: 06/S0801/77) and
breast milk (BM) collected at 2 (2W) and 6 weeks (6W) postpartum (Wales
Research Ethics Committee: 2004/024) archived prior to the COVID-19
pandemic were available. All samples were rendered cell free by
centrifugation and breast milk defatted prior to arhciving. ELISAs
(DuoSet, R&D Systems) were performed to determine the concentration of
sACE2 (catalogue number: DY933), sCD26 (DY1180), sCD147 (DY972) and
sNRP-1 (DY3870) in AF and 2W and 6W BM (Figure 1A). Statistics were
performed using a one-way ANOVA; a p value of < 0.05 was
deemed significant. Immunoblotting analysis (ACE2 (15983), CD26 (67138),
Cell Signalling Technologies; CD147 (AF972), Bio-Techne; NRP-1
(ab81321), Abcam) was used to confirm findings from the ELISAs and
reveal different isoforms (Figure 1B).