Virginia Research Day 2025

Medical Student Research Biomedical

11 The Effects of Quaternary Ammonium Compound Exposure on Embryonic Heart Development

Ashley Jordan 1 ; Terry C. Hrubec 1,2 Corresponding author: ajordan@vcom.edu

1 Edward Via College of Osteopathic Medicine, VA Campus 2 Virginia-Maryland College of Veterinary Medicine

Quaternary ammonium compounds (QACs) are commonly found in cleaners and disinfectants used in medical and household settings. However, little is known regarding the safety of this common class of chemicals. Recent work, by our lab and others, has shown that QACs are reproductive and developmental toxicants, as well as inhibitors of mitochondrial function and cholesterol synthesis. Gestational exposure causes neural tube defects and alterations to facial morphology with reductions in forebrain and pharyngeal arch area following QAC exposure. The exposed embryos also demonstrated significant reduction in palate width and width to-length ratio. A possible mechanism for altered pharyngeal arch and facial dysmorphology is decreased neural crest migration into the pharyngeal arches. Pharyngeal arch neural crest also contributes

to heart development. This study investigated whether heart morphology was affected by QAC exposure. We hypothesized if mice were exposed to QACs during development we would be able to quantify changes to the heart morphology compared to unexposed controls. Female mice were dosed with 60 mg/kg/day Alkyldimethylbenzyl ammonium chloride + Didecyldimethyl ammonium chloride (ADBAC+DDAC) in the feed throughout breeding and gestation. Heart development was evaluated in gestation day 10 (GD10) embryos standardized to 7 caudal somites. The area of the atria and ventricles both measured individually (left and right) as well as together as a region (ex. ventricular region), the length of the bulboventricular groove, and the width of the truncus arteriosus were measured using ImageJ software. Measurements were determined

as a proportion of crown to rump length. Statistical differences were determined by a two-sample t-test. Preliminary data show exposed embryos had reduced right ventricular area and an increased angle to the bulboventricular groove. This study may ultimately help illustrate that phenotypic development can be altered by ADBAC+DDAC exposure. The resultant morphologic changes could lead to congenital heart defects which are associated with pulmonary hypertension, arrythmias, infective endocarditis, and other disorders. Given that 100% of people sampled post COVID 19 pandemic had QAC residues in their blood and the potential for harm from exposure, we need to be more scrupulous in our use of QACs in common products and limit exposure, especially during times of pregnancy.

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