Lesmana, R. | bioRxiv Science

bioRxiv2024

Vanillin flavor in e-liquids does not induce endothelial cell dysfunction: the Replica Project

BackgroundThere are challenges that require collaboration among researchers to ensure that tobacco harm reduction strategies are evidence-based. One key challenge is evaluating the safety of flavors used in electronic cigarettes (e-cigarettes). While many flavorings are approved as food additives or deemed "generally recognized as safe" (GRAS) for ingestion, this does not guarantee their safety when inhaled. In this context, the international research group Replica replicated a study conducted by Fetterman and colleagues in 2018, investigating the effects of aerosolized vanillin - one of the most popular flavors in vaping - on vascular endothelium when vaporized by an electronic cigarette. MethodsWe used Aspire Zelos 3 e-cigarette and prepared e-liquids containing propylene glycol, vegetable glycerin and vanillin. The e-liquids were vaporized under two settings - regular (1 ohm coil using wattage control mode at 14 watts) and sub-ohm (0.3 ohm coil using temperature control mode at 200 {degrees}C) - using a vaping machine, following the standardized puffing regime, ISO20768:2018. The vapor was then collected into a trapping solution to prepare aqueous extracts for the treatment of human aortic endothelial cells. We evaluated cytotoxicity, oxidative stress, nitric oxide bioavailability, and inflammation addressing some gaps reported in the original study. ResultsWe observed some harmful effects, mostly attributable to ethanol, used to dilute vanillin in the original work by Fetterman, but no harmful effects on cell viability, their ability to produce nitric oxide, or oxidative stress from vanillin. Furthermore, no pro-inflammatory effects of vanillin were observed in terms of ICAM-1 and IL-6 gene expression. ConclusionsOur results confirm the endothelial cell dysfunction observed in the original paper, but clarify that these effects are mainly attributable to ethanol and not to vaporized vanillin. These findings suggest that vanillin could be a safer flavoring agent for e-cigarette, without causing adverse effects on the cardiovascular system.

pharmacology and toxicology↗

bioRxiv2022

Nicotine measurement on Cambridge Filter PADs: an interlaboratory comparison to evaluate exposure by different electronic devices and traditional cigarette

Inter-laboratory comparison is widely used to ensure quality control among laboratories. In in vitro toxicology studies for tobacco harm reduction (THR), exposure system performance and laboratory proficiency along with product smoke and aerosol stream are tested for variability to assess accuracy. Here we aim to test a novel inter-laboratory setup created in a new collaborative research group using identical and small footprint systems- in order to minimize variability factors and increase reproducibility. Seven independent laboratories from different geographical areas tested the aerosol and smoke stream and exposure system performance (LM1 and LM4E) using Cambridge Filter Pad (CFP) trapping techniques. We tested 1R6F reference cigarettes, two electronic cigarettes (Vype e-Pen and Vype e-Stick Maxx), and two tobacco heating products (IQOS and Glo) under the appropriate ISO and/or HCI regimes. Nicotine quantification was performed by GC-FID at the laboratory of the leading center. The performance of participant laboratories was assessed by z-score values obtained from results either in relation to the mean and standard deviation of total participants or in relation to the reference leading center. Z-Scores were satisfactory when |z| [≤] 2, questionable when 2 < |z| < 3 and, unsatisfactory when |z| [≥] 3. In the first evaluation, for all the tested devices, Z- scores values generated by dosimetry data ranged from -2 to +2. However, high intra-laboratory variability (RSD> 10%) was observed for almost all laboratories. In the second, data showed borderline and unsatisfactory exposure performances versus LAB-A. Particularly, Z-scores [≥] 3 were observed once for LAB-B (e-Stick exposure) and LAB-G (e-Pen exposure), twice for LAB-C (1R6F-ISO and e-Stick exposures) and LAB-E (e-Pen and e-Stick exposures), and three times for LAB-F (1R6F-HCI, e-Pen, and Glo exposures). This study demonstrates that nicotine dosimetry is a fundamental method for quality assurance of smoke/vapor run exposure in the early stage of an interlaboratory study, allowing the identification and possibly the resolution of gaps. Extended practice sessions on exposure runs and several rounds of nicotine dosimetry testing should be planned to keep in check overall equipment and operator performance.

pharmacology and toxicology↗