Prenatal iron deficiency alters mouse brains despite later iron supplementation

In a nutrition-based mouse study, researchers at the University of Rochester Medical Center found that iron deficiency during pregnancy produced persistent changes in the developing brain that were not fully reversed when offspring received iron-sufficient food after birth. Although supplementation normalized iron levels in the blood, the brain retained abnormal mineral levels and changes in the activity of genes associated with neurodevelopment. The findings indicate that recovery of blood iron after a period of gestational deficiency may not mean that iron-related effects in the brain have also been restored.

The researchers fed female mice iron-sufficient or iron-deficient diets before conception and maintained those diets throughout pregnancy. At birth, all offspring were switched to an iron-sufficient diet, allowing the team to examine whether cellular changes associated with prenatal deficiency could be rescued during early life. The study followed the mice from early development into young adulthood and was published in The Journal of Nutrition under the title “Postnatal Iron Supplementation Fails to Fully Rescue Brain Metal and Transcriptional Defects Caused by Nutrition-Based Gestational Iron Deficiency.”

Following the dietary change, iron concentrations in the offspring’s blood returned to normal. The same normalization did not occur throughout the brain. Some regions remained deficient in iron, while others accumulated more iron than expected. The researchers also detected an imbalance in several other minerals involved in development and cellular function, including calcium, magnesium, manganese, copper and zinc. These mineral abnormalities were more pronounced in the brain than in the blood, suggesting that a prenatal or postnatal blood analysis could underestimate the extent of lasting tissue-specific changes. The study therefore examined recovery through direct assessment of the brain rather than relying on blood iron measurements alone.

Beyond altered metal levels, the prenatal deficiency was associated with changes in gene-expression networks involved in brain development and communication between brain cells. The researchers observed changes in myelin formation, the process that produces the insulating structure around nerve fibers and supports efficient signaling between neurons. They also found differences in the expression of genes associated with neurodevelopment and autism spectrum disorder. The direction and extent of these changes varied by brain region: genes were less active in the cortex, hippocampus and thalamus, but more active in the posterior cortex. Some of the most extensive transcriptional changes occurred in the superior colliculus, a region involved in processing sensory information and directing attention. The authors identified this sensory-processing area as a particularly vulnerable part of the brain in the deficient offspring.

The results show that feeding iron after birth did not fully undo the molecular and functional effects of iron deficiency during gestation in this mouse model. They do not establish that the same degree or pattern of persistence occurs in human pregnancies, nor do they demonstrate that later iron treatment causes specific neurological disorders in people. The work used dietary deficiency to model gestational iron deficiency and assessed mineral concentrations, myelin-related changes and regional gene expression in mice, providing a controlled experimental setting for following effects from early life into young adulthood. The authors said the findings support a need for brain-specific biomarkers that could reveal consequences of gestational iron deficiency that are not apparent from blood iron levels alone. For Margot Mayer-Proschel, lead author and a professor of Biomedical Genetics and Neuroscience at the University of Rochester School of Medicine & Dentistry, the results highlight the possibility that current clinical measures may underestimate the long-term effects of prenatal iron deficiency on brain development.

Subject of Research: Mouse-model evidence that gestational iron deficiency produces persistent brain mineral and gene-expression changes that postnatal iron supplementation does not fully reverse.

Article Title: Prenatal iron deficiency leaves lasting changes in the developing brain

Article References: Prenatal iron deficiency leaves lasting changes in the developing brain. Original publication (Bibliographic details unavailable.)

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Keywords: prenatal iron deficiency, gestational nutrition, brain development, postnatal supplementation, mouse model, gene expression, brain minerals, myelin formation, sensory processing, University of Rochester, Prenatal, iron