Untargeted Metabolomics to Characterize the Urinary Chemical Landscape of E-Cigarette Users.

Introduction:
This text discusses a study that aimed to characterize the shifts in the chemical landscape of urinary biomolecules attributed to vaping. The study used urine samples from vapers, smokers, and nonusers and analyzed them using liquid chromatography-high resolution mass spectrometry (LC-hRMS). The study identified and characterized 336 chemicals with structural information that showed a difference in the urine samples among the vapers, smokers, and nonusers, including members of nicotine and non-nicotine alkaloids, potential flavoring agents, plasticizers, and nitrosamine.

Key Points:

* The study used LC-hRMS to analyze urine samples from vapers, smokers, and nonusers.
* The study identified and characterized 336 chemicals with structural information that showed a difference in the urine samples among the vapers, smokers, and nonusers.
* The identified chemicals included members of nicotine and non-nicotine alkaloids, potential flavoring agents, plasticizers, and nitrosamine.
* The study found similar urinary levels of nicotine species between vapers and smokers, but the flavoring agents and diethyl phthalate (DP) were highest in the urine of vapers.
* The study also observed distinctive changes in the urinary endogenous metabolites between vaping and smoking, including multiple species of fatty acids, esters, amides, and acylcarnitines.
* The study found that more lipids were metabolized for the mitochondria to produce energy in vapers than in smokers or nonusers, indicating higher lipid peroxidation.
* The study also observed higher susceptibility to change in females than in males for both smokers and vapers, suggesting that sex can be involved in the exposomic and metabolomic differences under vaping and smoking.

Main Message:
The study highlights the importance of using LC-hRMS to analyze urine samples to identify and characterize the shifts in the chemical landscape of urinary biomolecules attributed to vaping. The study found similar urinary levels of nicotine species between vapers and smokers, but the flavoring agents and DP were highest in the urine of vapers. The study also observed distinctive changes in the urinary endogenous metabolites between vaping and smoking, indicating that vaping can introduce xenobiotics and perturb biological functioning. These findings can drive new hypotheses for evaluating the health safety and toxicology of e-cigarettes.

hsiao YC, Matulewicz RS, Sherman SE, et al. Untargeted Metabolomics to Characterize the Urinary Chemical Landscape of E-Cigarette Users. Chemical research in toxicology. 2023;36(4):630-642. doi:10.1021/acs.chemrestox.2c00346