Perinatal lipocalin-2 profile at the extremes of fetal growth.

BACKGROUND: Lipocalin-2 (LCN-2) has been identified as an osteoblast-secreted hormone regulating immunity, inflammation and metabolic homeostasis and has emerged as a diagnostic and prognostic biomarker for acute kidney injury in neonates. We investigated the impact of fetal growth on antepartum maternal serum, cord serum and breast milk LCN-2 concentrations and the associations of the latter with perinatal parameters. METHODS: Maternal serum, cord serum and breast milk LCN-2 concentrations were measured by ELISA in samples from 80 mothers who delivered 40 appropriate (AGA), 20 large for gestational age (LGA) and 20 intrauterine growth restricted (IUGR) neonates, classified by customized weight centiles. LCN-2 concentrations were associated with birth weight, customized centile, gender, maternal age and delivery mode. RESULTS: Antepartum maternal serum LCN-2 concentrations were significantly higher in women delivering AGA infants compared to the other two groups. Cord blood LCN-2 concentrations were significantly higher compared to maternal ones; furthermore, they were significantly elevated in the IUGR group compared to the LGA one (p = .019). Lowest concentrations were detected in breast milk, which did not differ between the three growth groups. A negative correlation was documented between cord blood LCN-2 concentrations and customized centiles (r: -0.304, p = .007). CONCLUSIONS: The higher cord serum LCN-2 concentrations, compared to maternal ones, may point to its fetal origin and potential role in intrauterine growth. The negative correlation of cord LCN-2 concentrations with customized centiles, possibly implies reduced nephron endowment/subclinical kidney damage in IUGR neonates. The extremely low LCN-2 breast milk concentrations could imply that the secretion of LCN-2 from maternal circulation to breast milk is not influenced by factors leading to intrauterine growth pathology.