부산대학교 도서관

CONTEXT:: The neonatal period, notably in preterm infants, is characterized by high sodium wasting, implying that aldosterone, the main hormone regulating sodium reabsorption, is unable to maintain sodium homeostasis. OBJECTIVE:: This study sought to assess aldosterone secretion and action in neonates according to gestational age (GA). DESIGN AND SETTING:: This was a multicenter prospective study (NCT01176162) conducted between 2011 and 2014 at five neonatology departments in France. Infants were followed during their first 3 months. PARTICIPANTS:: The 155 newborns included were classified into three groups: Group 1 (n = 46 patients), <33 gestational weeks (GW); Group 2 (n = 67 patients), 33–36 GW; and Group 3 (n = 42 patients), ≥37 GW. MAIN OUTCOME MEASURES:: Plasma aldosterone was measured in umbilical cord blood. Urinary aldosterone (UAldo) was assessed at day 0, day 3, month 1, and month 3 postnatal. The correlation between UAldo and the urinary Na/K ratio was determined as an index of renal aldosterone sensitivity. RESULTS:: UAldo significantly increased with GA: from 8.8 ± 7.5 μg/mmol of creatinine (Group 1) to 21.1 ± 21.0 (Group 3) in correlation with plasma aldosterone levels in all groups (P < .001), demonstrating its reliability. The aldosterone/renin ratio significantly increased with GA, suggesting an aldosterone secretion defect in preterm infants. UAldo and urinary Na/K were correlated in very preterm but not in term neonates, consistent with very preterm neonates being renal-aldosterone sensitive and term neonates being aldosterone resistant. CONCLUSIONS:: Very preterm infants have a previously unrecognized defective aldosterone secretion but conserved renal aldosterone sensitivity in the neonatal period, which modifies the current view of sodium balance in these infants and suggests alternative management approaches.