Cardiac Neural Crest Ablation and Prenatal Ethanol Exposure Result in Like Cardiac Defects

Prenatal ethanol exposure results in Fetal Alcohol Spectrum Disorder (FASD) in at least 1% of live births in the USA. Of these, 28.6% had congenital heart defects (CHDs). The reason for the CHDs is not known. Alcohol exposure might cause damage to a sensitive set of embryonic cells termed cardiac neural crest cells (NCCs). The hypothesis tested in this study was that cardiac NCC ablated embryos would share cardiac defects similar to those of the ethanol-exposed model. Fertilized quail eggs, an animal model with many cardiac similarities to humans, were incubated to neurulation. The experimental group had their cardiac NCCs specifically ablated with an infrared laser. After controls and cardiac NCC ablated groups developed to day 8, they were imaged using Optical Coherence Tomography (OCT) to create three-dimensional models of cardiac valve leaflets. OCT images were analyzed using imaging software (MATLAB and Amira) to render volumes of the valve leaflets.  Cardiac NCC ablated embryos had a significant reduction in the left atrioventricular septal valve leaflets by 43% (ANOVA) compared to the control. The left AV mural valve leaflet also appeared to be smaller by 38% compared to the control. The results were similar to those previously reported for ethanol-exposed embryos. These findings are consistent with the hypothesis that the alcohol may be acting to alter cardiovascular structure by disturbing cardiac neural crest cells.