Neurodevelopment and Neuroimaging in Parenterally-fed Infants and Young Children

Overview

Manganese (Mn) is an essential metal required for normal growth and development. However, exposure to high Mn levels can be toxic to the brain. The objectives of this project are to identify neonatal and young pediatric populations that are at increased risk of excessive brain Mn deposition and altered cognitive and motor development based on their dietary parenteral Mn exposure, and to make sound and evidence-based recommendations for appropriate Mn supplementation and monitoring of infants and young children receiving parenteral nutrition (PN). Our studies are designed to test the hypotheses that, compared with unexposed age-matched controls, infants and young children receiving prolonged Mn-supplemented PN will have increased deposition of Mn in their brains and lower scores on neurodevelopmental, cognitive and psychophysiological assessments.

Specific Aims have been designed to test these hypotheses in three developmentally distinct populations: 1. preterm infants and 2. full term infants in the Neonatal Intensive Care Unit (NICU) requiring prolonged PN and 3. older infants and young children on home PN. Mn neurotoxicity will be investigated by longitudinal assessments of cognitive (executive functioning battery), neurodevelopmental (Bayley III Scales of Infant Development), and psychophysiological (event-related potential) measures and will be correlated with brain deposition of Mn using the technique of magnetic resonance (MR) relaxometry in a vulnerable population of infants receiving Mn-supplemented PN and age-matched controls. This proposal addresses a clinically relevant and unexplored link between nutritional practices, brain Mn deposition and neurodevelopmental sequelae in an at-risk population of infants and young children utilizing state-of-the-art magnetic resonance imaging (MRI) technology and neurodevelopmental assessment techniques. The potential for increased brain Mn accumulation in infants, and by inference, the potential health risks associated with elevated brain Mn burden, represents crucial, unexplored issues of exposure and susceptibility. The potential contribution of Mn toxicity to the poor outcomes of infants dependent for an extended time on PN has not been fully acknowledged or studied. Improved understanding of the relationships between Mn exposure and developmental outcomes will undoubtedly lead to altered clinical practices and more careful monitoring of Mn intake and blood and/or brain Mn levels in high risk infants. Our studies will also contribute to an improved understanding of the value of non-invasive MR imaging in the monitoring of pediatric patients on PN.