[Studies on toxicity and inflammatory reactions induced by e-cigarettes : In vitro exposure of human nasal mucosa cells to propylene glycol at the air-liquid interface]. / Untersuchungen zum Schädigungspotenzial durch den Konsum von E-Zigaretten : In-vitro-Exposition von humanen Nasenschleimhautzellen mit Propylenglykol im Air-Liquid-Interface.

BACKGROUND: The e­cigarette has become increasingly popular in recent years. However, the question of toxicity is not yet clear and there is global uncertainty regarding the use of e­cigarettes. This is intensified by the fact that there is a lack of declaration of the liquid ingredients. OBJECTIVE: The present paper investigates propylene glycol, a major component of the liquids, for possible acute inflammatory reactions as well as cytotoxic and genotoxic effects on human nasal mucosa cells. MATERIALS AND METHODS: The nasal mucosa cells from 10 volunteers were cultivated at the air-liquid interface and then exposed to different concentrations of propylene glycol. The analysis was carried out using the trypan blue test, comet assay, micronucleus test, and interleukin (IL)-6 and IL­8 sandwich ELISA. RESULTS: The trypan blue test showed no reduction in vitality. No increase in IL­6 and IL­8 concentrations were detected in the sandwich ELISA. In the comet assay, the Olive tail moment showed a dose-dependent increase in DNA fragmentation compared to the negative control at all examined concentrations. A difference between the pure substance and the negative control was shown in the micronucleus test. CONCLUSION: Possibly repairable dose-dependent DNA fragmentation and profound DNA alterations at high concentrations of propylene glycol warrant enhanced genotoxicological studies. These should include long-term exposure studies and assessment of further ingredients of the liquids. Consequently, the manufacturers need to be forced to declare the latter.

[In vitro exposure of human nasal mucous membrane cells and lymphocytes to snuff]. / In-vitro-Exposition humaner Nasenschleimhautzellen und Lymphozyten mit Schnupftabak.

BACKGROUND: While an abundant number of studies concerning tobacco smoke and chewing tobacco show carcinogenic potential, there is little data on the consequences of snuff, especially on the cellular level. Therefore, the mutagenic effect of snuff is difficult to estimate and the WHO assessment of snuff being not carcinogenic is based on very limited data. OBJECTIVES: This paper investigates the potential cytotoxic and genotoxic effects of snuff on human lymphocytes and nasal mucosa cells. MATERIALS AND METHODS: Two types of snuff were used: one without menthol and one with a high degree of menthol. The necessary nasal mucosa cells and lymphocytes were collected from 10 subjects undergoing nasal obstruction surgery and incubated for one hour with a snuff-DMSO mixture (range 0.01-2000 µg/ml). Methods included the trypan blue test, the comet assay, and the micronucleus test. RESULTS: The trypan blue test showed no decrease in cell viability for either cell type. The comet assay revealed a significant increase in the Olive Tail Moment for lymphocytes starting at 100 µg/ml and at 1000 µg/ml for nasal mucosa cells. There was no significant increase in micronuclei according to the micronucleus test. No differences between these two types of tobacco were observed. CONCLUSION: The present study demonstrated genotoxic damage, such as DNA strand breaks, which may be repaired, but no non-repairable elevated micronuclei. The present findings cast doubts on the WHO assessment that snuff is not carcinogenic. However, for a sound assessment of the risk potential of snuff, further research on various genotoxic endpoints in human cells is warranted.