Assessment of genotoxicity of waterpipe and cigarette smoking in lymphocytes using the sister-chromatid exchange assay: a comparative study

In vitro cytotoxicity and mutagenicity of mainstream waterpipe smoke and its functional consequences on alveolar type II derived cells

INTRODUCTION

While waterpipe tobacco smoking has become a global phenomenon, its potential health consequences are poorly understood. In this manuscript, we report the in vitro mutagenicity of waterpipe smoke condensate (WSC), the alteration in cellular parameters of lung alveolar cells in response to WSC exposure and discuss the implication of cellular responses in the pathophysiology of chronic obstructive pulmonary disease (COPD).

METHODS

The mainstream WSC was generated using a standard laboratory machine protocol. We assessed its mutagenicity using Ames test. In addition, we studied the effect of WSC on the proliferation and cell cycle of alveolar type II cells and vascular endothelial cells. We also assessed the effect of WSC on the expression of genes involved in cell cycle arrest and inflammation.

RESULTS

Within the range of tested doses, WSC did not elicit sufficient response to be considered mutagenic in any of the strains tested (TA98, TA100, TA102, and TA97a) but were found to be toxic for strains TA97a and TA102 at the highest tested doses. However, WSC induced cell cycle arrest and cellular senescence mediated by the p53-p21 pathway. Also our study indicated that WSC induced an increase in the transcriptional expression of matrix metalloproteinases, MMP-2 and MMP-9 and an immune response regulator, Toll Like Receptor-4.

CONCLUSION

The data reported here represent the first in vitro demonstration of the effect of waterpipe smoke on cellular parameters providing evidence of the potential involvement of WPS in the pathogenesis of COPD through impairing cellular growth and inducing inflammation.

Assessment of DNA damage using chromosomal aberrations assay in lymphocytes of waterpipe smokers

OBJECTIVES

The aim of this study was to investigate the genotoxicity of waterpipe smoking in the lymphocytes of waterpipe smokers using chromosomal aberrations (CAs) assay.

MATERIALS AND METHODS

Fifty waterpipe smokers and 18 healthy non-smokers volunteered to participate in the study. Additionally, 18 heavy cigarette smokers were recruited for comparison. Chromosomal aberrations (CAs) assay was used to evaluate DNA damage in the lymphocytes.

RESULTS

The results showed that similarly to cigarette smoking, waterpipe smoking significantly increased the frequencies of CAs (p < 0.01). In addition, the frequencies of CAs increased with more waterpipe use.

CONCLUSIONS

Waterpipe smoking causes DNA damage to lymphocytes and the damage increases with more waterpipe use.

Tobacco-specific nitrosamine exposures in smokers and nonsmokers exposed to cigarette or waterpipe tobacco smoke

INTRODUCTION

The causal relationship between tobacco smoking and a variety of cancers is attributable to the carcinogens that smokers inhale, including tobacco-specific nitrosamines (TSNAs). We aimed to assess the exposure to TSNAs in waterpipe smokers (WPS), cigarette smokers (CS), and nonsmoking females exposed to tobacco smoke.

METHODS

We measured 2 metabolites, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (NNAl-Gluc) in the urine of males who were either current CS or WPS, and their wives exposed to either cigarette or waterpipe smoke in a sample of 46 subjects from rural Egypt.

RESULTS

Of the 24 current male smokers, 54.2% were exclusive CS and 45.8% were exclusive WPS. Among wives, 59.1% reported exposure to cigarette smoke and 40.9% to waterpipe smoke. The geometric mean of urinary NNAL was 0.19 ± 0.60 pmol/ml urine (range 0.005-2.58) in the total sample. Significantly higher levels of NNAL were observed among male smokers of either cigarettes or waterpipe (0.89 ± 0.53 pmol/ml, range 0.78-2.58 in CS and 0.21-1.71 in WPS) compared with nonsmoking wives (0.04 ± 0.18 pmol/ml, range 0.01-0.60 in CS wives, 0.05-0.23 in WPS wives, p = .000). Among males, CS had significantly higher levels of NNAL compared with WPS (1.22 vs. 0.62; p = .007). However, no significant difference was detected in NNAL levels between wives exposed to cigarette smoke or waterpipe smoke.

CONCLUSIONS

Cigarette smokers levels of NNAL were higher than WPS levels in males. Exposure to tobacco smoke was evident in wives of both CS and WPS. Among WPS, NNAL tended to increase with increasing numbers of hagars smoked/day.

Waterpipe tobacco products: nicotine labelling versus nicotine delivery

BACKGROUND

Waterpipe tobacco package labelling typically indicates "0.0% tar" and "0.05% or 0.5% nicotine".

OBJECTIVE

To determine the extent to which nicotine labeling is related to nicotine delivery.

METHODS

110 waterpipe smokers engaged in a 45-minute waterpipe smoking session. Puff topography and plasma nicotine were measured. Three waterpipe tobacco brands were used: Nakhla (0.5% nicotine), Starbuzz (0.05% nicotine), and Al Fakher (0.05% nicotine). Data were analyzed by one-way ANOVA.

RESULTS

Topography did not differ across brands. Peak plasma nicotine varied significantly across brands. Al Fakher had the highest nicotine delivery (11.4 ng/ml) followed by Nakhla (9.8 ng/ml) and Starbuzz (5.8 ng/ml).

CONCLUSIONS

Nicotine labelling on waterpipe tobacco products does not reflect delivery; smoking a brand with a "0.05% nicotine" label led to greater plasma nicotine levels than smoking a brand with a "0.5% nicotine" label. Waterpipe tobacco products should be labelled in a manner that does not mislead consumers.

Waterpipe tobacco and cigarette smoking among university students in Jordan

SETTING

While waterpipe and cigarette smoking have been well studied in Syria and Lebanon, data from Jordan are limited.

OBJECTIVES

To characterize the relative prevalence of waterpipe tobacco and cigarette smoking among university students in Jordan, and to compare the demographic and environmental factors associated with each form of tobacco use.

DESIGN

We surveyed 1845 students randomly recruited from four universities in Jordan. We used multivariable logistic regression controlling for clustering of individuals within universities to determine associations between demographic and environmental covariates and waterpipe tobacco and cigarette use.

RESULTS

Waterpipe tobacco smoking rates were 30% in the past 30 days and 56% ever, while cigarette smoking rates were 29% in the past 30 days and 57% ever. Past 30-day waterpipe tobacco smoking rates were 59% for males and 13% for females. Females had substantially lower odds than males of being current waterpipe (OR 0.12, 95%CI 0.10-0.15) or cigarette (OR 0.08, 95%CI 0.05-0.14) smokers. Current cigarette smoking was more significantly associated with markers of high socio-economic status (SES) than waterpipe tobacco smoking.

CONCLUSION

Waterpipe tobacco smoking is as common as cigarette smoking among Jordanian university students. While cigarette smoking is consistently associated with high SES, waterpipe tobacco smoking is more evenly distributed across various populations.