1027 Parathyroid Hormone Related Protein (PTHRP) in Preterm Human Milk

Abstract

Background:Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcaemia. In a previous study we demonstrated high levels of PTHrP in both term and preterm human milk (HM) (Breastfeeding Medicine, 2009). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant (PTI) has not been studied yet.Objective: To assess the correlation between PTHrP level in preterm HM and PTHrP in maternal and neonatal serum. Design/Methods: We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks' gestation). In addition, blood samples from both mothers and infants were drawn. All samples were collected at days 2 and 10 postpartum. PTHrP levels were measured by twosite immunoradiometric assay. Blood calcium (Ca), Phosphorus (P) and alkaline phosphatase (ALP) levels were also measured.Results: Both maternal and neonatal PTHrP serum levles did not vary after 10 days of breastfeeding. No correlation was found between PTHrP level in HM and serum PTHrP, Ca, P and ALP of the breastfed PTI.Conclusions: Despite high levels of PTHrP in preterm HM, serum levels of PTHrP of the breast fed PTI do not increase over time. We found no correlation between PTHrP in HM and neonatal Ca serum concentration. We speculate that PTHrP intestinal absorption in the PTI is not significant.