Developmental Pattern of Urinary Epidermal Growth Factor in the Premature Infant and the Influence of Gender*

Abstract

We report the cross-sectional pattern of first day urinary epidermal growth factor/creatinine (EGF/Cr) levels in 159 appropriate for gestational age infants born at 26-41 weeks gestation. EGF/Cr levels rose significantly earlier in female infants than levels in male infants. In female infants levels were similar to term levels beginning at 30-32 weeks. Mean EGF/Cr levels in male infants were similar to term values beginning at 32-34 weeks. We could not demonstrate any influence from acute perinatal events on EGF/Cr levels. In a subset of 28 infants, a weekly longitudinal study of urinary EGF/Cr levels was undertaken. The urinary EGF/Cr pattern correlated significantly with both corrected gestational and postnatal ages. A significant change in the EGF/Cr pattern was observed at a corrected gestational age of 32 weeks and at 4 weeks postnatal age. There was no significant difference in EGF/Cr levels between males and females. Our results demonstrated a significant difference in first day urinary EGF/Cr levels between female and male preterm infants during the early third trimester. This difference was seen at a time in gestation when other gender-specific maturational and growth differences are noted. When infants born at less than 32 weeks gestational age were followed longitudinally, the urinary EGF/Cr pattern, when expressed by corrected gestational age, was significantly modified from that in the cross-sectional study.

Positive Relationship of Cortisol Concentrations and Oral Nutrition to Epidermal Growth Factor Concentrations in Preterm Infants

“…Our previous developmental study demonstrated significant gestational and postnatal age effects on EGF values but did not address changes during week 1 [8]. Weekly EGF concentrations spontaneously increased in infants who recovered from early lung disease.…”

“…Dexametha-sone therapy for CLD was associated with an increase in EGF concentrations. Our developmental studies demonstrated that increases in urinary EGF concentrations correlated to advancing gestational and postnatal age [8], but the factors which were important in determining the variability in EGF concentrations in week 1 were not defined. The possible role of EGF in gut development and disease was studied in infants with feeding intolerance or necrotizing enterocolitis where EGF values correlated with the severity of gut disease, and cessation of feedings decreased EGF values [9].…”

“…The urine samples were chilled during centrifugation at 1,000 g for 10 min and the sample was separated into two aliquots for measurement of EGF and creatinine and then frozen at -20°C until assayed. EGF was measured in a discontinuous, competitive RIA [8] previously described. Creatinines were measured using the picric acid method [10].…”

Correlation between Urinary Epidermal Growth Factor Excretion and Serum Thyroid Hormone in Premature and Term Neonates

“…However, Scott et al [4] demonstrated a significant nonlinear increase in urinary EGF/Cr ratio by 30–34 weeks of gestational age. Urinary EGF/Cr levels in those premature infants of gestational age 30–34 weeks were similar to the values of full-term neonates.…”

“…Although still not clear, the role of EGF in renal development and maturation has been suggested. Several studies [3, 4, 5, 6] showed evidence of renal origin of urinary EGF in human neonates, developmental patterns of urinary EGF in premature infants, and decreased urinary EGF excretions in neonates with intrauterine growth retardation. In animal experiments, thyroid hormone can enhance renal EGF synthesis and thus increase urinary EGF excretion [7, 8, 9].…”