In utero exposure to electronic cigarette carriers alters craniofacial morphology

Area of Science:

• Toxicology
• Developmental Biology
• Public Health

Background:

• Electronic nicotine delivery systems (ENDS) are popular, but e-liquid formulations lack consistent regulation.
• Common e-liquids contain propylene glycol (PG) and vegetable glycerin (VG); higher VG content is often chosen to reduce potential harm.
• Previous research linked PG-based e-liquids to increased carcinogens and nicotine uptake.

Purpose of the Study:

• To investigate the impact of different PG/VG ratios on craniofacial development in the absence of nicotine.
• To test the hypothesis that a 30/70 PG/VG formulation is safer than a 50/50 PG/VG formulation regarding craniofacial growth.

Main Methods:

• In utero exposure of mouse litters to control (free air), 30/70 PG/VG, or 50/50 PG/VG e-liquid components.
• Assessment of skull morphology in pups at postnatal day 14.

Main Results:

• The 30/70 PG/VG exposed group showed significant reductions in body weight, facial, and cranial dimensions.
• No significant differences in craniofacial growth were observed between the control and 50/50 PG/VG groups.

Conclusions:

• A shift towards VG-centric e-liquid formulations (30/70 PG/VG) may not mitigate health concerns associated with ENDS use.
• Propylene glycol and vegetable glycerin are not inert carriers and may pose risks.
• Nicotine-free ENDS formulations, particularly those with higher VG content, may not be safe for use during pregnancy.