Is Maternal Iron Status a Risk Factor in Fetal Alcohol Syndrome?

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DESCRIPTION (provided by applicant): Fetal Alcohol Spectrum Disorder (FASD) is the leading known cause of mental retardation. Its severity increases with parity, prompting suggestions that parity depletes some maternal factor/s that otherwise attenuate alcohol's effects on the fetus. While many speculate that this factor is nutritional, this hypothesis remains largely untested. We hypothesize that the parity factor/s reflect the micronutrient deficiencies that frequently accompany alcoholism. This R21 proposal focuses specifically on iron deficiency (ID), the most common nutrient deficiency in pregnant women. Gestational ID causes behavioral deficits that strongly parallel those of FASD, suggesting that ID and alcohol may synergize to heighten alcohol's neurotoxicity. This pilot study gathers preliminary data in support of this hypothesis. We will test this hypothesis using an established rat model in which early postnatal alcohol exposure disrupts cerebellar neuronal populations and cerebellum-dependent learning. Specifically, we will expose the offspring of iron-sufficient (IS) or ID pregnant rats to alcohol or control solution from postnatal day 4 (P4) to P9, and they are evaluated thereafter as follows: Aim 1) At P10 and P35, cerebellar populations are assessed with respect to overall morphology, apoptosis and proliferation. Cortical Purkinje cells and deep interpositus neurons are quantified using unbiased stereology; oligodendrocytes, astrocytes and myelin content are quantified using immunochemistry. Expression and distribution of iron regulatory proteins and of iron-responsive proteins mediating GABA and glutaminergic signaling are measured by western blot and immunohistochemistry. We predict that gestational ID will exacerbate one or more of alcohol's effects on cerebellar populations, and that such changes may persist into adolescence. Aim 2) Cerebellum-dependent learning is tested at P32 using eyeblink classical conditioning (ECC); brains are harvested for the P35 histology / stereology studies of Aim 1. Because the neural circuitry controlling ECC and alcohol's effects upon it are well understood, we can directly correlate the functional and cellular changes. We predict that ID will accentuate the alcohol-induced impairment of ECC, supporting the hypothesis that maternal micronutrient status modulates alcohol's neurotoxicity. Micronutrient supplements offer inexpensive and easy perinatal interventions to reduce alcohol's damage to the fetus. This goal directly fits the NIAAA mission to identify and reduce the causes of alcohol-induced neurodevelopmental and neurobehavioral disorders. PUBLIC HEALTH RELEVANCE: Fetal alcohol syndrome is the leading known cause of mental retardation. This work tests the hypothesis that nutritional factors may exacerbate alcohol's effects upon the fetus or infant. It addresses the concept that nutritional intervention might reduce FASD incidence for women at risk.