Glucocorticoid Induced Rise in Serum Leptin Is Associated with Poor Growth in Sick Preterm Infants

Abstract 1710 Neonatology: Clinical Studies in the Premature Infant Platform, Tuesday, 5/4

Background: Sick preterm infants treated with dexamethasone(dx) may have growth failure in spite of adequate nutrition. We have previously reported that dx leads to a rise in serum leptin (Peds Res 1998;43:338-43). Purpose: To study the effect of dx induced increase in serum leptin on weight gain pattern of sick preterm infants in relation to total caloric intake.

Methods: 24 neonates were studied of which 14 were randomized to receive a 3 day course of dx on day 1 and later all neonates received dx in ≤ 4 wks. of life based on clinical need. A blood sample was collected from these neonates at day 1(cord), 14 and 28. Serum leptin was measured by radio-immunoassay. Total caloric intake (enteral and parenteral) was measured on day 14 and 28 of life. Weight gain during the first 28 days of life was recorded. Results: Study infants had a mean birth Wt. of 864 ± 273 g (range 520-1755g), & gest. age of 26.6 ± 2.4 wks. (range 23-32 wks.). Cord blood leptin was higher in infants whose mother received antenatal steroids (1.98 ± 1.05 ng/ml vs .94 ± 0.39 ng/ml, p=0.004). Postnatal use of dx led to a rise in serum leptin from 1.52 ± 1.0 ng/ml at birth to 2.2 ± 1.3 ng/ml on day 28 of life (p=0.03). An inverse exponential relationship was observed between average serum leptin and postnatal weight gain by day 28 of life (R²=0.43) (Fig.). Total caloric intake on day 14 and 28 of life did not show any correlation with postnatal weight gain by day 28 of life (R²=.002 and .03 on day 14 and 28 respectively). Conclusions: An elevation in serum leptin due to glucocorticoids may be the mechanism for the poor weight gain in sick preterm neonates.

Fig 1

Weight gain relationship to leptin