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Infantile Iron Deficiency Affects Brain Development in Monkeys Even After Treatment of Anemia
Roza M Vlasova1, Qian Wang2, Auriel Willette2
1Department of Psychiatry, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Insights
Iron deficiency anemia (IDA) in infancy can lead to lasting brain development deficits, even after prompt iron treatment. Early detection and supplementation are crucial for preventing neural consequences in infants.
Area of Science:
- Neuroscience
- Developmental Biology
- Pediatrics
Background:
- Infant brain growth requires significant oxidative energy metabolism.
- Iron deficiency anemia (IDA) can impair brain growth and neurobehavioral development.
- Iron is prioritized for red blood cells over the brain during deficiency.
Purpose of the Study:
- To investigate the neural effects of transient iron deficiency (ID) in infant primates.
- To determine if brain deficits persist after iron treatment in anemic infants.
- To assess brain maturation at 1 year following prompt treatment of anemia.
Main Methods:
- A primate model (infant rhesus monkeys) was used (n=41).
- Hematology and iron status were monitored; 15 infants developed ID, 12 were treated for anemia.
- MRI volumetric and diffusion tensor imaging (DTI) were performed at 1 year.
Main Results:
- Infants with a history of ID showed smaller total brain volumes, primarily due to reduced gray matter (GM).
- Specific cortical regions exhibited smaller GM volumes.
- Diffusion tensor imaging revealed negative effects on two developing white matter tracts, despite normal white matter volumes.
Conclusions:
- Iron is essential for normal brain development.
- Brain structure and white matter microstructure differences persisted even after iron treatment and hematological recovery.
- Early detection and preemptive iron supplementation are vital to mitigate neural consequences of infant IDA.
Abstract:
A high percent of oxidative energy metabolism is needed to support brain growth during infancy. Unhealthy diets and limited nutrition, as well as other environmental insults, can compromise these essential developmental processes. In particular, iron deficiency anemia (IDA) has been found to undermine both normal brain growth and neurobehavioral development. Even moderate ID may affect neural maturation because when iron is limited, it is prioritized first to red blood cells over the brain. A primate model was used to investigate the neural effects of a transient ID and if deficits would persist after iron treatment. The large size and postnatal growth of the monkey brain makes the findings relevant to the metabolic and iron needs of human infants, and initiating treatment upon diagnosis of anemia reflects clinical practice. Specifically, this analysis determined whether brain maturation would still be compromised at 1 year of age if an anemic infant was treated promptly once diagnosed. The hematology and iron status of 41 infant rhesus monkeys was screened at 2-month intervals. Fifteen became ID; 12 met clinical criteria for anemia and were administered iron dextran and B vitamins for 1-2 months. MRI scans were acquired at 1 year. The volumetric and diffusion tensor imaging (DTI) measures from the ID infants were compared with monkeys who remained continuously iron sufficient (IS). A prior history of ID was associated with smaller total brain volumes, driven primarily by significantly less total gray matter (GM) and smaller GM volumes in several cortical regions. At the macrostructual level, the effect on white matter volumes (WM) was not as overt. However, DTI analyses of WM microstructure indicated two later-maturating anterior tracts were negatively affected. The findings reaffirm the importance of iron for normal brain development. Given that brain differences were still evident even after iron treatment and following recovery of iron-dependent hematological indices, the results highlight the importance of early detection and preemptive supplementation to limit the neural consequences of ID.
