# Dose-Dependent Health Impacts of Flavorings in E-cigarette Liquids Assessed via Sensory Irritation in the Mouse Airway

> **NIH NIH R21** · UNIVERSITY OF MARYLAND BALTIMORE COUNTY · 2020 · $142,054

## Abstract

Abstract
The abuse use of electronic cigarette (e-cig) or vaping is a worldwide health problem. Major symptoms of e-cig,
or vaping, product use-associated lung injury (EVALI) include cough and shortness of breath. In general,
sensory irritation induced by chemical or mechanical stimulation in the lower airway, such as trachea triggers
reflexive cough and dyspnea. However, we lack a direct assessment of sensory activation induced by e-cig
constituents, tetrahydrocannabinol (THC) and vitamin E acetate that potentially cause EVALI. Furthermore,
there is a lack of research data whether chronic vaping neurogenically hyper-sensitizes the airway. In our
parent grant project, we electrophysiologically record event-related potentials (ERP) in the nasal mucosa to
objectively assess sensory irritation evoked by e-cig flavorings, nicotine, PG/VG and flavored popular e-liquids.
Our data have demonstrated dose-dependent sensory activation evoked by these e-liquid constituents. We
hypothesize that certain e-liquid constituents cause sensory irritation in the trachea, which subsequently
triggers reflexive cough and dyspnea, and that long-term e-cig vapor exposure hyper-sensitizes the airway
mucosa. We will test our hypotheses by pursuing research: 1) measuring ERP from mouse tracheal mucosa to
evaluate sensory irritation caused by e-liquid constituents, THC and vitamin E acetate, 2) monitor and correlate
tracheal mucosal sensory irritation with respiratory alteration, and 3) determining whether 2-week vapor
exposure sensitizes the tracheal mucosa resulting in potentiated responses to e-liquid constituents and tussive
stimuli. We have accumulated sufficient data from our parent grant project that will enable us to speed up this
proposed research substantially by narrowing the tested stimulus concentration ranges. Importantly, we have
successfully measured in vivo ERP responses to some e-liquid flavorings, nicotine, and tussigenic capsaicin,
and acetic acid from tracheal epithelium that has intact nerve innervation. This direct recording from trachea
mucosa presents an innovative approach for the risk assessment of e-cig vaping. Together, our preliminary
data promise for time-sensitive, significant results towards a better understanding of the health effects of e-cig
vaping and causal factors of EVALI and help guide FDA regulation of e-cig manufacture and sale.

## Key facts

- **NIH application ID:** 10064412
- **Project number:** 3R21DA046349-02S1
- **Recipient organization:** UNIVERSITY OF MARYLAND BALTIMORE COUNTY
- **Principal Investigator:** WEIHONG LIN
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $142,054
- **Award type:** 3
- **Project period:** 2020-03-01 → 2021-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10064412

## Citation

> US National Institutes of Health, RePORTER application 10064412, Dose-Dependent Health Impacts of Flavorings in E-cigarette Liquids Assessed via Sensory Irritation in the Mouse Airway (3R21DA046349-02S1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10064412. Licensed CC0.

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