*4.4. Enzyme-Linked Immunosorbent Assay (ELISA)*

Total proteins were isolated from PDMSCs-CM-treated and untreated PE placentae using 1X radio immunoprecipitation assay (RIPA) buffer. Quantitative measurement of sFlt-1 (R&D System, Milan, Italy), TNF-α (RayBiotech, Prodotti Gianni, Milan, Italy), and IL-6 (Abcam, Milan, Italy) placental levels were determined using commercially available competitive ELISA kits according to manufacturer's instruction.
