**12. Summary**

Several studies focused on EVs (mainly small EVs called exosomes) highlighting their extraordinary characteristics as natural carriers of bioactive molecules, which can be used as biomarker for several pathological conditions including PE. These vesicles are unique in terms of their cell trafficking and transfecting capabilities. These nanovesicles are released from almost all types of cells into different human body fluids. Their release and contents are dependent on the microenvironment where the cells are exposed and the origin of the cells [172]. Therefore, EVs can be used as a diagnostic tool as well as prognostic marker for several pathologies, and we have proposed that the analysis of placental vesicles in maternal plasma can function as a liquid biopsy to establish placental function during pregnancy. During pregnancy, placenta and other cells, such as platelets and immune cells, secrete exosomes into the maternal circulation; this process is exaggerated in pathological pregnancies (i.e., PE, PIH, IUGR) in an attempt to modulate the pathology [43,190,191]. Very few studies [218,219] have been conducted to identify the particular mechanism of action that exosomes can produce on the placenta and overall maternal physiological system when treated with low dose aspirin and other antithrombotic medication. An avenue is open to explore the placental and other cell derived exosomal

functions in placental dysfunctional disorders when treated with antithrombotic medications including low dose aspirin. A better understanding of these processes may lead to the development of novel prognostic markers utilizing placenta specific exosomes or for monitoring the response to aspirin treatment for placental pathologies.

**Funding:** Carlos Salomon is supported by The Lions Medical Research Foundation, National Health and Medical Research Council (NHMRC; 1114013) and the Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT 1170809). Suchismita Dutta received the Australian postgraduate award scholarship.

**Conflicts of Interest:** The authors declare no conflict of interest.
