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Parathyroid hormone-related protein in tracheal aspirates of newborn infants
M V Speziale1, F L Mannino, R H Hastings
1Department of Pediatrics, University of California, San Diego, La Jolla 92093, USA.
Insights
Parathyroid hormone-related protein (PTHrP) levels in newborn tracheal aspirates correlate with lung maturation. Lower PTHrP is linked to prematurity, low birth weight, and surfactant use, suggesting a role in fetal lung development.
Area of Science:
- Biochemistry
- Developmental Biology
- Neonatology
Background:
- Parathyroid hormone-related protein (PTHrP) plays a role in embryonic tissue growth and differentiation.
- PTHrP stimulates phosphatidylcholine synthesis, indicating a potential role in fetal lung maturation and surfactant production.
Purpose of the Study:
- To investigate PTHrP levels in tracheal aspirates of newborn infants.
- To explore the association between PTHrP levels and indicators of lung maturation in neonates.
Main Methods:
- Tracheal aspirates were collected from 40 intubated newborn infants within 24 hours of birth.
- PTHrP levels were quantified using radioimmunoassay (RIA).
Main Results:
- Significantly lower PTHrP levels were observed in infants born before 35 weeks gestation and those with birth weight < 2 kg.
- Male preterm infants and those requiring multiple surfactant doses had lower PTHrP levels.
- Antenatal steroid exposure was associated with significantly higher PTHrP levels.
Conclusions:
- PTHrP levels in neonatal tracheal aspirates are associated with indices of lung maturation.
- PTHrP may act as a mediator of lung differentiation and growth in newborns.
Abstract:
PTH-related protein (PTHrP) is found with its receptor in a variety of normal mammalian embryonic tissues where it apparently regulates cellular growth and differentiation. PTHrP stimulates phosphatidylcholine synthesis in rat fetal lung explants, suggesting a role in fetal type II alveolar maturation and surfactant production. We investigated PTHrP levels in tracheal aspirates of newborn infants. We collected tracheal aspirates from 40 intubated newborn infants within the first 24 h of life. PTHrP levels were measured by a RIA using rabbit antisera to PTHrP peptide 38-64. We found significantly lower PTHrP levels in tracheal aspirates from infants born at less than 35 wk of gestation (p = 0.02) and with a birth weight less than 2 kg (p = 0.04). We also found significantly lower PTHrP levels in male preterm (<35 wk of gestation) infants compared with female infants (p = 0.01), and in preterm infants who required multiple doses of surfactant (p = 0.005). Preterm infants exposed to antenatal steroids had significantly higher levels of PTHrP in tracheal aspirates (p = 0.02). PTHrP is associated with various indices of lung maturation and may prove to be a mediator of differentiation and growth.