Fomepizole fails to prevent progression of acidosis in 2-butoxyethanol and ethanol coingestion

Distinct genetic regions are associated with differential population susceptibility to chemical exposures

Interactions between environmental factors and genetics underlie the majority of chronic human diseases. Chemical exposures are likely an underestimated contributor, yet gene-environment (GxE) interaction studies rarely assess their modifying effects. Here, we describe a novel method to profile the human genome and identify regions associated with differential population susceptibility to chemical exposures. Single nucleotide polymorphisms (SNPs) implicated in enriched chemical-disease intersections were identified and validated for three chemical classes with expected GxE interaction potential (neuroactive, hepatoactive, and cardioactive compounds). The same approach was then used to characterize consumer product classes with unknown risk for GxE interactions (washing products, cosmetics, and adhesives). Additionally, high-risk variant sets that may confer differential population susceptibility were identified for these consumer product groups through frequent itemset mining and pathway analysis. A dataset of 2454 consumer product chemical-disease linkages, with risk values, SNPs, and pathways for each association was developed, describing the interplay between environmental factors and genetics in human disease progression. We found that genetic hotspots implicated in GxE interactions differ across chemical classes (e.g., washing products had high-risk SNPs implicated in nervous system disease) and illustrate how this approach can discover new associations (e.g., washing product n-butoxyethanol implicated SNPs in the PI3K-Akt signaling pathway for Alzheimer's disease). Hence, our approach can predict high-risk genetic regions for differential population susceptibility to chemical exposures and characterize chemical modifying factors in specific diseases. These methods show promise for describing how chemical exposures can lead to varied health outcomes in a population and for incorporating inter-individual variability into chemical risk assessment.

Acute toxicity classification for ethylene glycol mono-n-butyl ether under the Globally Harmonized System

Acute oral, dermal and inhalation toxicity classifications of chemicals under the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS) should typically be based on data from rats and rabbits, with the tacit assumption that such characterizations are valid for human risk. However this assumption is not appropriate in all cases. A case in point is the acute toxicity classification of ethylene glycol mono-n-butyl ether (EGBE, 2-butoxyethanol, CAS 111-76-2), where acute toxicity data from rats or rabbits leads to an overly conservative assessment of toxicity. Hemolysis is the primary response elicited in sensitive species following EGBE administration and the proximate toxicant in this response is 2-butoxyacetic acid (BAA), the major metabolite of EGBE. The sensitivity of erythrocytes to this effect varies between species; rats and rabbits are sensitive to BAA-mediated hemolysis, whereas humans and guinea pigs are not. In this publication, a weight of evidence approach for the acute hazard classification of EGBE under GHS is presented. The approach uses acute toxicity data from guinea pigs with supporting mechanistic and pharmacokinetic data in conjunction with human experience and shows that adopting the standard method results in over-classification.

Severe poisoning after accidental pediatric ingestion of glycol ethers

Human glycol ether poisonings are sparsely reported in the medical literature. We describe a healthy 22-month-old boy who accidentally drank up to 330 mL of brake fluid containing a 75% bleed of various glycol ethers (5%-50% polyethylene glycol monomethyl ether, 15%-40% triethylene glycol monoethyl ether, 1%-30% triethylene glycol monomethyl ether, 1%-25% triethylene glycol monobutyl ether, 1%-20% polyethylene glycol, monobutyl ether, 1%-20% triethylene glycol, and <10% of other glycol ethers). Within 4 hours, he became somnolent and developed a persistent metabolic acidosis. Thirty minutes later, he received 1 dose of fomepizole. Neither progression nor improvement in clinical or metabolic status was noted after the fomepizole. He received hemodialysis for 3 hours ∼8 hours after ingestion, and his symptoms resolved resulting in an uneventfully recovery.