PECAM1 and hydrops fetalis: Interestingly, we found lower level of circulating proteins related to angiogenesis (Vascular endothelial growth factor A (VEGF-A), Kallikrein-6 (KLK6), Platelet endothelial cell adhesion molecule (PECAM1), Proteinase-activated receptor 1 (PAR1) and Matrix metalloproteinase-1 (MMP1) in OB HF patients (Fig. 3).