Chronological changes of serum exosome in preterm infants: A prospective study

Background Exosomes, which are observed in all human fluid, including serum, are nanosized extracellular vesicles with a mechanism of intercellular communication. Potential clinical applications of exosomes in neonatal diseases have recently been discussed. However, the characteristics of exosomes in serum during early infancy is unclear. Methods In this prospective study, we evaluated the chronological changes in the concentration of serum‐derived exosomes of 20 infants for 12 months after birth. Results The average concentration of serum‐derived exosomes was 4.6 × 1010 particles/mL at birth and increased significantly until the age of 48 weeks. There was a moderate correlation between the gestational age and the concentration of serum‐derived exosomes both at birth (r = 0.54, P = 0.01) and during the 8 weeks after birth (r = 0.48, P < 0.001). A multivariable analysis showed that gestational age at birth was associated with the concentration of serum‐derived exosomes at birth (partial regression coefficient, 0.86; 95% confidence interval, 0.37–1.37; P = 0.002). Conclusions The concentration of serum‐derived exosomes in preterm infants increased both chronologically and by gestational age after birth. These basic data may help to further understand physiology of exosomes in preterm infants.