Melatonin Vapes Contain Potential Contaminants and Alter the Human Bronchial Epithelial Transcriptome

Summary & key facts

Researchers tested three melatonin vaping products and exposed human airway cells grown in the lab to aerosol from one of the vapes. The vape aerosol delivered melatonin into the cells, changed which genes the cells turned on and off, weakened the cell layer that lines the airways, and reduced the release of several immune signaling molecules. Chemical testing of the products found common vape ingredients and potential contaminants, and one product did not even contain detectable melatonin. The study used cells in dishes and a small number of products and donors, so it shows possible harms but cannot tell us how these vapes affect real people long term.

Key facts:

• The team grew human bronchial airway cells from three adult donors and exposed the cells in the lab to aerosol from a commercial melatonin vape.
• The vape exposure deposited about 0.66 milligrams per square centimeter of aerosol and delivered roughly 80 micrograms of melatonin to the cell surface during the experiment.
• Melatonin from the surface moved into the airway cells quickly and reached a steady level by about six hours after treatment.
• Vape aerosol exposure lowered the electrical resistance across the cell layer right after exposure, which suggests the airway surface became more leaky or less intact.
• After 24 hours, the cells exposed to melatonin vape aerosol released lower amounts of several chemokines, which are molecules that call immune cells to the airway.
• Changes in gene activity were much larger after vape aerosol exposure than after the same amount of melatonin delivered in liquid: about 1,000 genes were affected by the vape aerosol compared with about 180 genes affected by aqueous melatonin.
• Gene changes after vape aerosol exposure pointed to reduced immune and antiviral pathways and increased signatures of low-oxygen response and cell growth, which the authors describe as an immunosuppressive pattern in the airway cells.
• Chemical analysis of three disposable melatonin vapes found common humectants like glycerin and flavoring chemicals, possible industrial or agricultural contaminants, and pharmaceutical compounds; only two of the three products showed detectable melatonin.
• The study did not find significant cell death after 24 hours, but the authors note that short-term lack of cell death does not rule out other harmful effects or long-term damage.
• The authors emphasize that these results come from lab-grown cells and a small set of products, so more research is needed to understand local and whole-body harm in people who use melatonin vapes.

Abstract

Melatonin vaping products, touted for their faster absorption than oral melatonin supplements, have been gaining popularity among adolescents as sleep aid. Here, we elucidated the response of human bronchial epithelial cells (hBECs) to high levels of melatonin from vaped aerosols, investigated the uptake of melatonin by hBECs in vitro, and characterized the chemical composition of three commercially available melatonin vapes. Melatonin vape exposure decreased the secretion of chemokines and produced an immunosuppressive gene expression signature. The tested devices contained potential contaminants, including pharmaceuticals and industrial chemicals. Further investigation is needed for melatonin vapes to determine their local and systemic toxicity.

Topics

Asthma and respiratory diseases Circadian rhythm and melatonin Neonatal Respiratory Health Research

Categories

Endocrine and Autonomic Systems Life Sciences Neuroscience

Tags

Biochemistry Biology Cell biology Chemistry Computational biology Contamination Ecology Endocrinology Environmental chemistry Gene Gene expression Melatonin Transcriptome

Substances

Other

Conditions & symptoms

Sleep disorder Poor sleep