A review of the role of extracellular vesicles in neonatal physiology and pathology.

Extracellular vesicles (EVs) are cell-derived membrane-bound particles, extensively investigated across many fields to improve the understanding of pathophysiological processes, as biomarkers of disease and as therapeutic targets for pharmacological intervention. We aim to describe the current knowledge of EVs detected in the body fluids of human neonates, both term and preterm, from birth to 4 weeks of age. To date, EVs have been described in several neonatal body fluids, including cerebrospinal fluid, umbilical cord blood, neonatal blood, tracheal aspirates and urine. These studies demonstrate some important roles of EVs in the neonatal population, particularly in haemostasis. Moreover, some studies have demonstrated the pathophysiological mechanisms and the identification of potential biomarkers of neonatal disease. We must continue to build on this knowledge, evaluating the role of EVs in neonatal pathology, particularly in prematurity and during the perinatal adaption period. Future studies should use larger numbers, robust EV characterisation techniques and always correlate the findings to clinical outcomes. IMPACT: This article summarises the current knowledge of the effect of EVs in neonates. It describes the potential compensatory role of EVs in neonatal haemostasis. It also describes the role of EVs as mediators of pathology and as potential biomarkers of perinatal and neonatal disease.