High Iron Diet During Prenatal Alcohol Exposure (PAE) May Normalize Iron Homeostasis in PAE Fetuses
Authors: Cheng Adrienne A. , Huebner Shane M. , Smith Susan M. 
Published: November 2023

Prenatal alcohol exposure (PAE) is the leading cause of cognitive and learning defects. Previous studies in our lab have shown that iron deficiency (ID) during pregnancy exacerbates the behavioral and growth deficits of PAE. Rat fetuses that were both ID and exposed to PAE had increased liver iron stores but decreased brain iron, indicating an inability for these fetuses to maintain proper iron homeostasis. The goal of this study was to investigate whether iron supplementation preceding and during pregnancy could mitigate alcohol's disruption of fetal iron homeostasis. Two weeks prior to pregnancy, female rats were fed otherwise identical diets that were either iron sufficient (IS) and contained 100ppm iron, or had high iron (IX) and contained 500ppm iron. Pregnant dams received either 5g/kg ethanol (E)(200 proof, USP) or an isocaloric maltodextrin (MD) control as a split dose two hours apart on gestation days (GD) 13.5 through 19.5. Maternal and fetal tissues were collected on GD20.5. Total tissue mineral content was analyzed using inductively coupled plasma mass spectroscopy (ICP‐MS). Homeostatic iron proteins Ferritin (FN), Transferrin (Tf), and Transferrin Receptor (TfR) were quantified using Western Blot and normalized to GAPDH. There was a significant effect of alcohol but not diet on mean fetal weight (p=0.0003), with the PAE fetuses being significantly smaller than their MD counterparts. Thus, the high iron diet did not improve fetal growth in PAE. The PAE fetuses had a higher percentage of brain mass relative to body size than the MD controls (p<0.0001), regardless of diet. Coupled with the fetal growth data, this indicates the possibility that energy is being used to promote fetal brain growth at the expense of peripheral tissues. Alcohol affected total iron in fetal brain (p=0.0147) such that the IS‐E group had significantly lower brain iron than IS‐MD (p=0.0003), whereas the brain iron content did not differ between the IX‐MD and IX‐E groups (p=0.99), suggesting that higher iron uptake may have mitigated some of alcohol's disruption of iron homeostasis. Both PAE and IX diet significantly increased fetal liver iron (p=0.0003 and p=0.0353, respectively). Neither diet nor alcohol significantly affected fetal liver expression of Tf, TfR, or FN, and did not alter Tf or TfR in fetal brain. However, IX‐E fetal brains had less ferritin expression than IS‐E fetuses (approaches significance at p=0.074), possibly because the high iron diet allowed iron to be more readily available as opposed to being stored. Quantification of heme iron versus non‐heme iron is underway. Altogether, these data indicate that a high iron intake may normalize fetal brain iron status and enhance liver iron content in an alcohol‐exposed pregnancy. Clinical studies show that maternal ID substantially enhances her child's vulnerability to PAE, and our work suggests an increased iron intake may improve those gestational outcomes.

Support or Funding Information

R01 AA22999, R37 AA11085, F32 AA21311