Stable precursor fragments of vasoactive peptides in umbilical cord blood of term and preterm infants.

BACKGROUND

Though various neurohormonal systems are concurrently activated during birth, their biological effectors are not always easy to measure due to their short half-life in vivo, instability in biological samples, or very low concentrations.

METHODS

Using a recently discovered chemiluminescence assay, we measured the stable precursor fragments mid-regional pro-atrial natriuretic peptide (MR-proANP), mid-regional pro-adrenomedullin (MR-proADM), C-terminal pro-endothelin-1 (CT-proET-1) and C-terminal pro-vasopressin (CT-proAVP or copeptin) immediately after birth in umbilical venous cord blood from 119 infants with a gestational age of 23-42 weeks and evaluated their possible functions.

RESULTS

Cord blood levels of MR-proANP, MR- proADM, CT-proET-1, and CT-proAVP were considerably higher compared with normal adult levels. The CT-proAVP concentrations were 10-fold higher in term, and 70-fold higher in extremely preterm infants. MR-proANP showed 4-fold higher levels in term infants and 20-fold higher levels in extremely preterm infants. Levels of MR-proADM and CT-proET-1 were 2- to 3-fold higher in preterm and term infants. All four parameters showed significantly decreased values with increasing gestational age and a significant correlation between CT-proET-1 and MR-proADM.

CONCLUSION

Our results indicate that vasoactive and natriuretic mediators play a functionally relevant role in circulatory transition from fetal to neonatal life.