Low vs. High Wattage Vaping during Pregnancy Influences Vascular Function in Rat Offspring

Abstract

Electronic cigarettes (e‐cigs) are being marketed as a healthier alternative to traditional cigarettes, yet the health consequences of e‐cig usage (also called vaping) are still being investigated. E‐cigs are easily customized for user preferences. For example, choice of flavors, nicotine concentration, and/or temperature (i.e. wattage) used to combust the e‐liquid can be selected in many devices. Emerging evidence suggest vaping during pregnancy impairs cerebral vascular function in rodent offspring. In this study, we sought to investigate the potential effects of changes in e‐cig device wattage (i.e. 5 watts vs 30 watts) with maternal vaping during pregnancy of vascular function in postnatal life of offspring. METHODS: Adult female Sprague Dawley rats were time‐mated to allow for maternal e‐cig exposure beginning on gestation day 2 until birth. Maternal vaping occurred for 1 h/day, 5 days/wk using a whole‐body chamber system. E‐cig aerosol was generation using D19 Joyetech atomizer with nicotine‐free (0 mg/mL) 50:50 VG:PG e‐liquid without flavoring. Puff topology was 83 ml with 5‐sec puff duration. Pregnant dams were randomly assigned to control (air‐exposed), 5 watt or 30‐watt exposure groups. Rat offspring (n=2/dam) were studied at 30‐, 90‐, and 180‐days after birth, where in vivo pulse wave velocity (an index of arterial stiffness) was assessed using VisualSonics Vevo 2100 ultrasound, thereafter animals were euthanized and thoracic aortas were excised, cleaned, and cut into 2mm rings for wire myography (DMT, AD instruments). Aortic rings were mounted and warmed in aerated Krebs‐Henseleit buffer solution. Vessel reactivity was measured using serial dilutions of methacholine [MCh 10‐9to 10‐5M] and sodium nitroprusside [SNP 10‐9 to 10‐5 M] to assess endothelial‐dependent vasodilation (EDD) and endothelium‐independent vasodilation (EID), respectively. RESULTS: At the 30‐days, max aortic EDD was not different between either 5W (79±17%, mean±SD) or 30W (86±4%) groups compared to controls (88±4%)(p>0.36). At 90‐days, max aortic EDD was lower with 30W (58±18%, p<0.001), but not 5W (78±4%, p=0.11) compared to controls (95±6%). Carotid PWV was elevated in 5W (3.49 m/s) and 30W (3.83 m/s) groups compared to controls (2.98 m/s, p<0.05) suggesting 17‐29% increase in arterial stiffness. At 180 days, max aortic EDD was also lower with 30W (75±12%, p<0.01), but not 5W (81±9x%, p=0.11) compared to controls (100±10%). Carotid PWV was elevated further in 5W (3.96 m/s) and 30W (4.29 m/s) groups compared to controls (3.13 m/s, p<0.05) revealing 27‐37 % increase in arterial stiffness. Maximal aortic EID response (to SNP) was not different by wattage group or age. CONCLUSIONS: These findings show that e‐cig device power used during maternal vaping plays a role in increasing arterial stiffness and blunting EDD vascular function in the postnatal life of offspring with effects worsening with age. These data suggest vaping during pregnancy is not safe and has long‐lasting consequences to vascular health of progeny.