A Synthetic Coolant (WS-23) in Electronic Cigarettes Disrupts Normal Development of Human Embryonic Cells

Electronic cigarettes (ECs) often contain high concentrations of WS-23, a synthetic coolant. Our goal was to determine if WS-23 activates TRPM8 channels in human embryonic stem cells (hESCs), leading to abnormal embryonic development. Nanomolar concentrations of WS-23 triggered calcium influx in hESCs, as visualized using Fluo-8. Live cell imaging showed that 26 to 2600 nM of WS-23 inhibited hESC colony growth in a concentration dependent manner. Growth inhibition was caused by an increase in cell death and a reduction in cell division. Exposure to nM WS-23 inhibited mitochondrial reductases in the MTT assay, altered colony morphology, and induced formation of gaps between cells. The above processes were blocked by a TRPM8 channel antagonist. WS-23 at concentrations as low as 26 nM caused loss of OCT4 (a pluripotency marker) in hESCs and expression of SOX17 (an endoderm marker). These data show that WS-23 could reach an embryo during maternal vaping at concentrations sufficient to disrupt normal development.