Objective-A number of studies suggest that Pb exposure increases cardiovascular disease risk in humans. As a potential mechanism for this effect, we recently reported a significant association between early childhood Pb levels and cardiovascular response to acute stress. The current study considers the association between current Pb levels and the autonomic nervous system activation pattern underlying the cardiovascular response to stress in a new cohort of children.Methods-We assessed blood Pb levels as well as cardiovascular responses to acute stress in 9-11 year old children (N = 140). Sympathetic activation (measured with pre-ejection period) and parasympathetic activation (measured with high frequency heart rate variability) were also assessed.Results-In a sample with very low levels of blood Pb (M = 1.01 μg/dL), we found that increasing blood Pb was associated with coinhibition of sympathetic and parasympathetic activation in response to acute stress. In addition, increasing Pb levels were associated with the hemodynamic stress response pattern typical of coinhibition -significantly greater vascular resistance and reduced stroke volume and cardiac output. Conclusions-BloodPb levels were associated with significant autonomic and cardiovascular dysregulation in response to acute psychological stress in children. Moreover, these effects were significant at Pb levels considered to be very low and notably well below the 10 μg/dL the Centers for Disease Control and Prevention definition of an elevated blood Pb level. The potential for Corresponding Author: Brooks B. Gump, PhD, MPH, 414 Mahar Hall, Department of Psychology, SUNY Oswego, Oswego, NY 13126, Ph: 315-312-4150, Fax: 315-342-2064, gump@oswego.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. [7]. For example, children that showed heightened cardiovascular responses to a series of acutely stressful laboratory tasks (e.g., hand tracing a pattern using only the mirror image as a guide) were at significantly greater risk of elevated resting blood pressure 6.5 years later [8]. Finally, findings from a number of studies suggest a small but significant positive association between Pb exposure and resting blood pressure [9,10]. Therefore, it is possible that repeated and exaggerated Pb-induced vascular responses to acute stress produce vascular remodeling and subsequent hypertension [11], thereby explaining the association between Pb exposure and baseline blood pressure. In order to increase our understanding of the association between Pb and vascular responses to acute stress, the present study investigates...

Background The potential harm from exposure to nonessential metals, particularly mercury (Hg) and lead (Pb), has been the focus of research for years. Initial interest focused on relatively high exposures; however, recent evidence suggests that even high normal exposures might have adverse consequences for child development. Identifying the extent of these consequences is now a priority. Methods We assessed blood Pb and Hg levels in a biracial sample of 9–11 year-old children (N = 203). Neurodevelopment and psychological functioning assessments included hostility, disruptive behaviors, emotion regulation, and autism spectrum disorder behaviors. Parasympathetic (vagal) responses to acute stress were indexed by heart rate variability (HRV) at rest and during stress. Results With increasing Pb levels, children exhibit higher levels of hostile distrust and oppositional defiant behaviors, were more dissatisfied and uncertain about their emotions, and had difficulties with communication. These significant associations were found within a range of blood Pb levels from 0.19 to 3.25 μg/dL, well below the “reference value” for children of >5 μg/dL. Vagal reactivity interacted with Hg such that increasing Hg was associated with increasing autism spectrum behaviors for those children with sustained vagal tone during acute stress. Conclusions This study is the first to demonstrate an association between very low-level Pb exposure and fundamental psychological mechanisms that might explain prior associations with more complex outcomes such as delinquency. Analyses of vagal reactivity yielded entirely novel associations suggesting that Hg may increase autism spectrum behaviors in children with sustained vagal tone during acute stress. The novelty of these later findings requires additional research for confirmation and the cross-sectional nature of the data caution against assumptions of causality without further research.

Heavy metal exposure in children has been associated with a variety of physiological and neurological problems. The goal of this study was to utilize proteomics to enhance the understanding of biochemical interactions responsible for the health problems related to lead and mercury exposure at concentrations well below CDC guidelines. Blood plasma and serum samples from 34 children were depleted of their most abundant proteins using antibody-based affinity columns and analyzed using two different methods, LC-MS/MS and 2-D electrophoresis coupled with MALDI-TOF/MS and tandem mass spectrometry. Apolipoprotein E demonstrated an inverse significant association with lead concentrations (average being one microgram/deciliter) as deduced from LC-MS/MS and 2-D electrophoresis and confirmed by Western blot analysis. This coincides with prior findings that Apolipoprotein E genotype moderates neurobehavioral effects in individuals exposed to lead. Fifteen other proteins were identified by LC-MS/MS as proteins of interest exhibiting expressional differences in the presence of environmental lead and mercury.