Meconium Proteins as Potential Biomarkers for Fetal Iron Status and Intrauterine Inflammation

The lack of specific biological materials and biomarkers limits our knowledge of the mechanisms underlying intrauterine regulation of iron supply to the fetus. Determining the meconium content of proteins functionally related to the regulation of iron metabolism may explain their role in fetal development. This study assesses the homeostasis of iron metabolism in intrauterine fetal development by determining the concentrations and interdependencies in neonatal meconium proteins commonly recognized in laboratory diagnostics for the assessment of iron status. Ferritin, transferrin, haptoglobin, ceruloplasmin, lactoferrin, myeloperoxidase (MPO), neutrophil gelatinase-associated lipocalin (NGAL), and calprotectin were determined by ELISA in meconium samples obtained from 122 neonates. Statistical analysis was performed by using Statistica Version 13 (StatSoft Inc., TIBCO Software Inc., Palo Alto, CA, USA). There were strong correlations between the meconium concentrations of haptoglobin, transferrin, and NGAL (p < 0.05). Meconium concentrations of ferritin were several-fold higher than the concentrations of the other proteins, with the exception of calprotectin whose concentration was approximately three-fold higher than that of ferritin. Meconium ceruloplasmin concentration significantly correlated with the concentrations of MPO, NGAL, lactoferrin, and calprotectin. Strong correlations between specific proteins in meconium, such as haptoglobin, transferrin, and NGAL, suggest their collaborative involvement in iron homeostasis within the fetus. Furthermore, the study's findings provide valuable information about the potential role of ceruloplasmin in regulating neutrophil activity in the intrauterine environment.