The platelet releasate (PR) in human pregnancy

Healthy pregnancy is characterized by an increase in platelet activation and a decrease in the number of circulating platelets with gestation. Despite this recognised importance, proteomic studies investigating platelets in healthy pregnancy have not been performed. As platelet cargo can be altered in different conditions, we hypothesised that platelets may store a relevant and bespoke collection of molecules during pregnancy. To examine this, we performed comparative label-free quantitative proteomic profiling of platelet releasates from healthy pregnant and non-pregnant women using a tandem mass spectrometry approach. Of the 723 proteins identified, 69 PR proteins were found to be differentially released from platelets in pregnancy, including proteins only expressed during pregnancy such as pregnancy-specific glycoproteins and human placental lactogen.