Alfredo Nunziata

A review of in vitro methods to assess the biological activity of tobacco smoke with the aim of reducing the toxicity of smoke

In the last few years tobacco companies have been developing several research strategies in order to reduce the risks associated with smoking. These strategies include, for example, the refining of alternative cigarette designs that reduce the amount of hazardous chemicals in the mainstream smoke by introducing modified filters, and/or reducing the amount of biologically significant ingredients in tobacco-burning cigarettes. In the last few decades numerous studies have been published to assess the biological activity of tobacco smoke using in vivo and in vitro test systems. In this scenario a general scientific consensus on how to measure and characterize the risk associated with cigarette smoke is still lacking. Short-term in vitro assays, which are widely accepted by regulatory agencies around the world, are useful tools to evaluate both the biological activity and the progress towards a reduction of tobacco smoke toxicity. These assays could be mainly applied to evaluate cytotoxicity and genotoxicity properties on whole cigarette smoke as well as condensates or fractions of whole smoke. Cytotoxicity induction can be measured as cellular viability and growth rates using different end-points. Otherwise, the target of genotoxicity studies is the DNA molecule. For genotoxicity evaluation, the end-points and cell systems should be chosen from those that are relevant and appropriate as clinical surrogate markers. In this respect, the occurrence of early biological effect markers, such as mutational or clastogenic events (point mutations, frameshifts, micronuclei, SCE, DNA adducts) in bacterial and mammalian cells should be studied in a tiered approach following the guidelines of regulatory agencies. The choice of criteria shall be matter of discussion.

Biomarkers of lung damage associated with tobacco smoke in induced sputum.

Cigarette smoking has been causally linked several diseases, primarily lung cancer and chronic obstructive lung disease (COPD). The diagnosis of COPD currently involves an assessment of smoking and/or occupational exposures, a history of cough, sputum and dyspnea and spirometric measures of airflow obstruction and since spirometric measures take long follow up times to detect significant changes, surrogate measures of outcome capable of predicting long-term health changes have been sought for. These include biomarkers of oxidative stress, inflammation and tissue damage in sputum, bronchoalveolar lavage, exhaled breath and serum. Published biomarker studies have not always accurately compared patients with COPD with age-matched cigarette smokers and non-smoking normal subjects without significant airflow limitation, also comparable for other exposures. Consequently, the interpretation of biomarker association studies is somewhat difficult. The purpose of this narrative review is to summarize publications reporting cellular, soluble or volatile marker of obstructive lung disease in populations of healthy non-smokers and healthy smokers, in order to determine whether the biomarkers examined could be specifically associated with exposure to tobacco smoke rather than with inflammation and airway hyper-reactivity. As induced sputum has been the most widely used investigative tool, this review has been aimed at assessing induced sputum biomarkers, referring to lung biopsy, bronchoalveolar lavage and exhaled breath markers as supporting evidence for biomarkers associations identified with induced sputum studies.

Cardiovascular Biomarkers in Groups of Established Smokers after a Decade of Smoking

To investigate tools for evaluation of smoking-associated disease initiation and progression, we examined basic clinical parameters and biomarkers of cardiovascular disease risk, in a group of healthy volunteers with an average 10-year smoking history. A small cross-sectional study of never-smokers, moderate smokers and smokers was performed. Caucasians were recruited to match pre-defined cigarette tar yields and cigarettes smoked per day. For haematological parameters, significant differences between never-smokers and all female smokers combined were seen for haemoglobin concentration, haematocrit, total leucocyte count, neutrophil count and lymphocyte count. For all male smokers combined, only total leucocyte count was statistically different. Analysis of exhaled CO and other smoke exposure biomarker (nicotine and its metabolites) data showed a statistically significant increase in all groups of smokers with a trend related to the number of cigarettes smoked per day. Thromboxane urinary metabolites 11-dehydro-thromboxane B(2) and 2,3-dinor-thromboxane B(2) were statistically significantly elevated in smokers. Significant statistical differences between smokers with approximately 10 years of smoking history and non-smokers in white cells count, hemoglobin and thromboxane turnover were seen, although they did not reach levels associated with overt diseases. These data could provide insight into early biomarkers predictive of risk for coronary and vascular disease.

A cross-sectional investigation of biomarkers of risk after a decade of smoking

Two groups of 20 healthy volunteers with cigarettes of different tar yield were compared with a group of 20 never smokers over 24 h for several biomarkers. All groups were of similar mean ages and the smokers had smoked for a homogeneous period of approximately 10 yr. The groups were assessed using routine medical parameters as well as biomarkers of recent smoke exposure and other biomarkers that were under evaluation as possible markers of risk for smoking-associated diseases. All biomarkers of exposure—carbon monoxide, nicotine plus its five major metabolites, and 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL)—were significantly elevated in smokers. For biomarkers of potential risk evaluated in the blood, white cells and immunoglobulin (Ig) G showed a decrease related to smoking status (p < .01). Interleukin 6 levels were higher in smoker groups compared to never smokers, with a significant increasing trend across the groups (p < .05). Among the urinary biomarkers studied, 11-deydro-thromboxane B2, 2,3-dinor-thromboxane B2, and thymidine glycol showed significant increasing trends across the groups (p < .01). The results suggest that after the first decade or less of smoking, changes in inflammatory, immunological, and cardiovascular function can be observed. However, further studies on larger groups will be required to better understand the kinetics of these subtle effects observed early in smokers and their relationship with the potential risk of subsequent smoking-associated disease.

Effects of cigarette smoking on circulating leukocytes and plasma cytokines in monozygotic twins

Abstract Background: Despite the well-documented role of cigarette smoke in the development of chronic obstructive pulmonary disease (COPD), lung cancer and cardiovascular disease, biomarkers for screening or monitoring disease progression and outcome remain elusive, particularly for COPD and lung cancer. Inflammatory cells and mediators are likely to be involved in the disease processes, but their importance is still poorly understood. The purpose of this study was to investigate early changes in immunological markers associated with smoking in healthy monozygotic twins without a detectable disease discordant for smoking, thereby minimising data variability due to genetic background. Methods: Twenty-two monozygotic twin pairs, aged 31.5±6.3 years, entered the study. One of each twin pair was a smoker and the other a non-smoker. None of the subjects reported any diseases or clinically defined respiratory symptoms or airflow limitation. Each subject donated blood samples for determination of total leukocytes and subpopulations, lymphocyte subpopulation plus pro-inflammatory mediators (interleukin-8, tumour necrosis factor-α, soluble tumour necrosis factor-α receptors and C-reactive protein). Results: We observed a significant increase in the number of circulating leukocytes and neutrophils in smokers compared to non-smokers. Smokers also had significantly higher numbers of B cells and CD4+ T cells, plus an increased CD4/CD8 ratio. The numbers of NK cells were statistically significant lower in smokers compared to non-smokers. Conclusions: While the prognostic significance of these changes is uncertain, results suggest that smoking is associated with immune changes, independent of genetic background and environmental conditions.

Effects of Ambient Air Pollution on Birth Outcomes: An Overview

The ambient air pollution (AAP) is ubiquitarian especially in the western countries and several studies have found correlations with different human pathologies (such as cardiovascular and respiratory diseases). In the last decades the scientific community has focused the studies on the possible effects of AAP on human reproduction, in particular on the pregnant women and birth outcomes. The researches have investigated the possible correlations between AAP and the effects of prenatal exposure and birth outcomes using several parameters such as low birth weight, intrauterine growth restriction, and preterm birth delivery. The authors found that the literature data are in conflict and do not reach univocal results. In fact, not all of the researches showed effects and correlations between AAP and birth outcomes and the studies are extremely various and do not use similar methods of analysis. Furthermore, the mechanisms of action are unclear. The possible difficulties in this matter should be the lack of an univocal guideline in the studies, the absence of the researches analyzing the particular internal composition of particulate matter, the possible overlap of short- and long-term exposure. In addition, the authors have verified the lack of studies of associations between the possible birth defects and ultrafine particulates (UFPs) able to move from pulmonary district to the circulatory system. Birth defects have a potential great impact on individual and public health because they may involve not only immediate but also future impairments of organs and/or metabolic functions. Therefore the authors suggest further studies that should be performed (a) using same guidelines, (b) analyzing not only the effects of the concentrations of the particulate matter but also of its particular internal composition, and (c) investigating the effects of UFPs on birth outcomes.

Cross-sectional study of biomarkers of exposure and biological effect on monozygotic twins discordant for smoking

Abstract Background: The aim of this study was to investigate the possible correlation between smoking status and biomarkers of exposure (BoE) and biological effect (BoBE) in monozygotic twins discordant for smoking status (smoker and non-smoker pairs). By eliminating potential genetic variability in this manner, a clearer pattern of the effects of lifestyle and environmental exposures should become apparent. Methods: This was a cross-sectional study on monozygotic healthy twins (44 subjects, 26 males and 18 females) with a mean age 31.5 years. BoE to cigarette smoke and BoBE were measured in body fluids (24 h urine and blood) after medical pre-screening. Results: All BoE were significantly higher in the smoker twins. Among BoBE, 11-dehydrothromboxane B2 (11-dehydro TBX), 2,3-dinorthromboxane B2 (2,3-dinor TBX), 8-epi-prostaglandin F2α (8-epiPGF), hydroxyproline (OH-P), fibrinogen, white blood cell (WBC), neutrophil and lymphocyte counts and heart rate were statistically significantly increased in the smoker compared to the non-smoker twins. Moreover, statistically significant correlations between neutrophil count and 11-dehydro TBX (r=0.32), WBC and 8-epiPGF (r=0.33), OH-P and 8-epiPGF (r=0.49) and heart rate and fibrinogen (r=0.46) were observed. Conclusions: The study results confirmed the reliability of the BoE for the evaluation of smoking status. Moreover, a subset of the BoBE, reported as being associated with inflammatory conditions and early stages of vascular disorders, has emerged as showing a consistent relationship with smoking status from the present and the previous studies. By using monozygotic twin pairs, genetic variability has been excluded as a possible source of variability in this study. These results should assist in the interpretation of other population studies using these biomarkers.

Smoking Selectively Accelerates Carotid Atherosclerosis in Hypertensive Patients

AbstractBackground and objectives: Left ventricular hypertrophy, carotid atherosclerosis and renal dysfunction are indicators of target organ damage in hypertension, and independent risk factors for both fatal and non-fatal cardio- and cerebrovascular events. In the general population, smoking is associated with increases in left ventricular mass and carotid intima-media thickness (IMT), and impaired renal function. The aim of the present study was to evaluate whether smoking affects the development of target organ damage in patients with arterial hypertension. Methods: 3192 hypertensive patients referred to the Hypertension Clinic of the “Federico II” University of Naples from January 2000 to July 2006 were retrospectively analysed. Subjects were aged from 18 to 75 years. Among these patients, 1391 were smokers and 1801 non-smokers. Results: The duration and severity of hypertension was significantly shorter in smokers when compared with non-smokers. The maximum arterial IMT was significantly higher in smokers compared with non-smokers (1.7 ± 0.1 mm vs 1.5 ± 0.1, p < 0.0001), while left ventricular mass index was comparable between the two groups. In contrast, glomerular filtration rate was observed to be higher in smokers compared with non-smokers. Logistic regression analysis showed that smoking, age, sex, duration of hypertension, systolic blood pressure and diastolic blood pressure were significantly correlated with IMT. Furthermore, a strong correlation was found between the number of cigarettes smoked per day and IMT. Conclusions: Together, these data indicate that in hypertensive patients who have a high risk of developing atherosclerosis, smoking could potentiate the development of atherosclerotic plaques.