Effect of cigarette smoke on salivary proteins and enzyme activities

Comparative effects of e-cigarette smoking on periodontal status, salivary pH, and cotinine levels

BACKGROUND

The nicotine in e-cigarette liquid can negatively impact periodontal tissues by altering the salivary pH and elevating cotinine levels. Thus, the study aimed to determine the periodontal parameters, salivary pH, and cotinine levels among cigarette, e-cigarette, and never-smokers.

METHODS

A total of 144 participants were recruited (48 cigarette smokers, 48 e-cigarette smokers, and 48 never-smokers). Clinical periodontal parameters, including plaque index (PI), gingival index (GI), periodontal probing pocket depth (PPD), and clinical attachment loss (CAL) were recorded, excluding third molars. The level of unstimulated whole salivary pH was measured using a portable pH meter and the levels of salivary cotinine were measured using Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

Data were analysed statistically using analysis of variance. Mean scores of PPD, percentage of pocket depth ≥ 4 mm, and CAL (p < 0.05) were significantly higher among cigarette smokers than those in e-cigarette and never-smokers, while GI (p < 0.05) were significantly higher among e-cigarette smokers. The unstimulated salivary pH was more acidic among cigarette smokers (p < 0.05) and e-cigarette smokers (p < 0.05) than in never-smokers. The cotinine levels were higher among cigarette smokers (p < 0.05) and e-cigarette smokers (p < 0.05) than in never-smokers.

CONCLUSIONS

Clinical periodontal parameters were poorer in cigarette smokers than in e-cigarette smokers and never-smokers. Meanwhile, cigarette and e-cigarette smokers have more acidic salivary pH and higher cotinine levels than in never-smokers.

The expression of salivary EGF, VEGF, endothelin, and transferrin in waterpipe and cigarette smokers

The aim of this study was to evaluate the effects of two forms of tobacco smoking, cigarettes and water pipe smoking (WPS), on the expression of a panel of salivary proteins in healthy adults. Three groups of age and gender-matched participants were enrolled in the study: never-smokers, cigarette smokers and WPS (N = 55 per group). Expression of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), endothelin and transferrin in unstimulated whole saliva was estimated using enzyme-linked immunosorbent assays. Statistical analysis consisted of one-way ANOVA and Tukey's post hoc tests, in addition to bioinformatics analysis. VEGF expression was the least in WPS (51.1 ± 14.5 pg/ml) compared to both controls (150.1 ± 13.8 pg/ml) and cigarette smokers (93 ± 9.9 pg/ml), with a significant difference in WPS (p < 0.001) and cigarette smokers (p < 0.01) compared to controls. Furthermore, transferrin showed the weakest expression in the WPS group (1238 ± 261.4 pg/ml) compared to controls (2205.6 ± 298.6 pg/ml) (p = 0.05) and cigarette smokers (1805.4 ± 244 pg/ml). Neither EGF nor endothelin expression showed any statistical difference between the groups (p > 0.05). Gene-gene interaction network demonstrated that FLT1, TFRC, KDR, VEGFB and PGF genes had the highest potential for interaction with the studied proteins. Further functional annotations on the identified markers in the interaction network were performed to identify HIF-1 pathways among the most relevant pathways. In conclusion, smoking habits alter the expression of salivary VEGF and transferrin, which may correspond to early sub-clinical changes in the oral mucosa. The clinical relevance of these salivary changes requires further research.

Effects of medwakh smoking on salivary metabolomics and its association with altered oral redox homeostasis among youth

The use of alternative tobacco products, particularly medwakh, has expanded among youth in the Middle East and around the world. The present study is conducted to investigate the biochemical and pathophysiological changes caused by medwakh smoking, and to examine the salivary metabolomics profile of medwakh smokers. Saliva samples were collected from 30 non-smokers and 30 medwakh smokers and subjected to metabolomic analysis by UHPLC-ESI-QTOF-MS. The CRP and Glutathione Peroxidase 1 activity levels in the study samples were quantified by ELISA and the total antioxidant capacity (TAC) by TAC assay kits. Statistical measurements and thorough validation of data obtained from untargeted metabolomics identified 37 uniquely and differentially abundant metabolites in saliva of medwakh smokers. The levels of phthalate, L-sorbose, cytosine, uridine, alpha-hydroxy hippurate, and L-nicotine were noticeably high in medwakh smokers. Likewise, 20 metabolic pathways were differentially altered in medwakh smokers. This study identified a distinctive saliva metabolomics profile in medwakh smokers associated with altered redox homeostasis, metabolic pathways, antioxidant system, and CRP levels. The impact of the altered metabolites in medwakh smokers and their diagnostic utility require further research in large cohorts.

Therapeutic Potential of Small Molecules Targeting Oxidative Stress in the Treatment of Chronic Obstructive Pulmonary Disease (COPD): A Comprehensive Review

Chronic obstructive pulmonary disease (COPD) is an increasing and major global health problem. COPD is also the third leading cause of death worldwide. Oxidative stress (OS) takes place when various reactive species and free radicals swamp the availability of antioxidants. Reactive nitrogen species, reactive oxygen species (ROS), and their counterpart antioxidants are important for host defense and physiological signaling pathways, and the development and progression of inflammation. During the disturbance of their normal steady states, imbalances between antioxidants and oxidants might induce pathological mechanisms that can further result in many non-respiratory and respiratory diseases including COPD. ROS might be either endogenously produced in response to various infectious pathogens including fungi, viruses, or bacteria, or exogenously generated from several inhaled particulate or gaseous agents including some occupational dust, cigarette smoke (CS), and air pollutants. Therefore, targeting systemic and local OS with therapeutic agents such as small molecules that can increase endogenous antioxidants or regulate the redox/antioxidants system can be an effective approach in treating COPD. Various thiol-based antioxidants including fudosteine, erdosteine, carbocysteine, and N-acetyl-L-cysteine have the capacity to increase thiol content in the lungs. Many synthetic molecules including inhibitors/blockers of protein carbonylation and lipid peroxidation, catalytic antioxidants including superoxide dismutase mimetics, and spin trapping agents can effectively modulate CS-induced OS and its resulting cellular alterations. Several clinical and pre-clinical studies have demonstrated that these antioxidants have the capacity to decrease OS and affect the expressions of several pro-inflammatory genes and genes that are involved with redox and glutathione biosynthesis. In this article, we have summarized the role of OS in COPD pathogenesis. Furthermore, we have particularly focused on the therapeutic potential of numerous chemicals, particularly antioxidants in the treatment of COPD.

Influence of Electronic Cigarettes on Selected Physicochemical Properties of Saliva

(1) Background: Electronic cigarettes are gaining more popularity not only among cigarettes smokers. Firstly, e-cigarettes were perceived as less harmful than traditional cigarettes, however, nowadays, they are arousing more controversy. The aim of this study was to assess the impact of e-cigarette usage on selected physicochemical properties of saliva. (2) Methods: The study population included 128 patients: 40 patients using e-cigarettes, 39 patients smoking traditional cigarettes, and 49 non-smoking patients (non-smokers). Laboratory tests involved verification of saliva values of pH and concentration of total protein, calcium, and phosphates. (3) Results: Among e-cigarette users, the value of pH was lower and the concentration of total protein, calcium, and phosphates was higher than in the group of non-smokers. Statistically significant differences were observed in relation to calcium. Among traditional cigarette smokers, the value of pH was lower, concentrations of total protein and phosphates were higher than in the group of non-smokers. Statistically significant differences were observed in relation to total protein. (4) Conclusions: Saliva of e-cigarette users presents changes in physicochemical composition in comparison to traditional cigarette smokers and non-smokers, however, statistically significant differences were observed only in calcium concentration. Further longitudinal studies on a larger study group should be conducted to assess the effect of observed changes in oral health.

Influence of Electronic Cigarettes on Antioxidant Capacity and Nucleotide Metabolites in Saliva

The balance between reactive oxygen species production and the activity of antioxidant systems present in saliva is an important element in maintaining oral environment homeostasis. E-cigarettes adversely affect the oral cavity and their cytotoxic effect is related to oxidative stress. The aim of this study was to assess the influence of using electronic cigarettes on antioxidant capacity of saliva. The study involved 110 subjects (35 e-cigarettes users, 33 traditional cigarettes smokers and 42 non-smokers). Laboratory analysis involved quantitation of uric acid, hypoxanthine, xanthine, TAOS (total antioxidant status) and TEAC (Trolox equivalent antioxidant capacity) in saliva. Lower values for TAOS and TEAC were observed among e-cigarettes users and traditional cigarettes smokers in comparison to non-smokers. Uric acid concentration tended to be higher among e-cigarettes users while no differences in hypoxanthine and xanthine saliva concentrations were observed. Electronic cigarettes usage affects antioxidant capacity of saliva to the same extent as traditional cigarettes, when comparing smokers to non-smokers. Further longitudinal studies on a larger study group are needed to assess the effect of changes in antioxidant status on oral health.

Salivary Malondialdehyde Level as a Lipid Peroxidation Marker in Early Childhood Caries

Background: Early childhood caries (ECC) is an aggressive and multifactorial form of dental caries in children, in which the biomarkers of oxidative stress may increase. Objectives: This study aimed to compare the salivary malondialdehyde (MDA) levels in children with early childhood caries (ECC) and caries-free (CF) children. Methods: To this end, 42 ECC children and 42 CF children, aged 4 - 6 years, were randomly selected from the kindergartens of four socio-economically different districts of Isfahan. An unstimulated saliva sample was obtained from children fasting during the past night using the spitting method. In the laboratory, the MDA levels were evaluated spectrophotometrically. An independent-samples t-test was used to examine the differences between the two groups. Results: The mean salivary MDA level was significantly higher in the ECC group than in the CF group (P = 0.01), and there was no significant relationship between salivary MDA and gender (P = 0.44 in the ECC group, P = 0.30 in the CF group). Moreover, no significant relationship was noticed between MDA with decayed, missing, filled teeth (dmft). Conclusions: The findings documented a relationship between ECC and MDA as one of the products of oxidative stress reactions. Accordingly, the MDA level of saliva can be a critical indicator in determining the status of caries in children.

Thioredoxin as a novel sensitive marker of biological stress response in smoking

Thioredoxin is a low molecular weight (approximately 12 kDa) redox protein, and protects against harmful stimuli such as oxidative stress. Smoking evokes oxidative stress, among other biological responses. The clinical relevance of thioredoxin in smoking has not been fully investigated. Here, we examined the effects of smoking on serum and urinary thioredoxin levels, in comparison with various stress markers. Serum thioredoxin levels in the smoking group (10 subjects) were significantly higher than those of the non-smoking group (5 subjects). After smoking, serum thioredoxin levels significantly decreased, while urinary levels significantly increased. On the other hand, the levels of serum and salivary cortisol, plasma norepinephrine, salivary amylase, salivary thioredoxin, and urinary 8-hydroxy-2'-deoxyguanosine levels before and after smoking were not significantly different. These results suggest that a decrease in thioredoxin in the serum and the concomitant increase in the urine is a novel sensitive marker of biological stress responses induced by smoking. The change seems to be evoked by mechanisms different from hormonal or 8-hydroxy-2'-deoxyguanosine-forming stress responses.

Influence of Electronic Cigarettes on Selected Antibacterial Properties of Saliva

The aim of this study was to estimate changes in selected physicochemical properties of saliva collected from users of electronic cigarettes. Methods: The study population consisted of 120 patients (40 users of electronic cigarettes, 40 smokers of traditional cigarettes and 40 non-smokers). Laboratory tests included verification of saliva amount of lysozyme, lactoferrin and IgA. Results: Among e-cigarette users, statistically significant differences were observed in values of lysozyme and lactoferrin; however, no statistically significant differences for the IgA value were found. In the group of traditional cigarette smokers, statistically significant differences were observed among all tested parameters in relation to the control group. In relation to IgA, statistically significant differences were found between e-cigarette users and traditional cigarette smokers, to the disadvantage of the latter. Conclusion: Saliva of e-cigarette users showed changes of antibacterial properties in comparison to the control group and traditional cigarette smokers. Further longitudinal studies on larger study groups should be conducted in order to assess the effect of observed changes in the antibacterial properties of saliva on oral health.

Incense Burning is Associated with Human Oral Microbiota Composition

Incense burning is common worldwide and produces environmental toxicants that may influence health; however, biologic effects have been little studied. In 303 Emirati adults, we tested the hypothesis that incense use is linked to compositional changes in the oral microbiota that can be potentially significant for health. The oral microbiota was assessed by amplification of the bacterial 16S rRNA gene from mouthwash samples. Frequency of incense use was ascertained through a questionnaire and examined in relation to overall oral microbiota composition (PERMANOVA analysis), and to specific taxon abundances, by negative binomial generalized linear models. We found that exposure to incense burning was associated with higher microbial diversity (p < 0.013) and overall microbial compositional changes (PERMANOVA, p = 0.003). Our study also revealed that incense use was associated with significant changes in bacterial abundances (i.e. depletion of the dominant taxon Streptococcus), even in occasional users (once/week or less) implying that incense use impacts the oral microbiota even at low exposure levels. In summary, this first study suggests that incense burning alters the oral microbiota, potentially serving as an early biomarker of incense-related toxicities and related health consequences. Although a common indoor air pollutant, guidelines for control of incense use have yet to be developed.

Types of tobacco consumption and the oral microbiome in the United Arab Emirates Healthy Future (UAEHFS) Pilot Study

Cigarette smoking alters the oral microbiome; however, the effect of alternative tobacco products remains unclear. Middle Eastern tobacco products like dokha and shisha, are becoming globally widespread. We tested for the first time in a Middle Eastern population the hypothesis that different tobacco products impact the oral microbiome. The oral microbiome of 330 subjects from the United Arab Emirates Healthy Future Study was assessed by amplifying the bacterial 16S rRNA gene from mouthwash samples. Tobacco consumption was assessed using a structured questionnaire and further validated by urine cotinine levels. Oral microbiome overall structure and specific taxon abundances were compared, using PERMANOVA and DESeq analyses respectively. Our results show that overall microbial composition differs between smokers and nonsmokers (p = 0.0001). Use of cigarettes (p = 0.001) and dokha (p = 0.042) were associated with overall microbiome structure, while shisha use was not (p = 0.62). The abundance of multiple genera were significantly altered (enriched/depleted) in cigarette smokers; however, only Actinobacillus, Porphyromonas, Lautropia and Bifidobacterium abundances were significantly changed in dokha users whereas no genera were significantly altered in shisha smokers. For the first time, we show that smoking dokha is associated to oral microbiome dysbiosis, suggesting that it could have similar effects as smoking cigarettes on oral health.

Salivary and Serum Antioxidant and Oxidative Stress Markers in Dental Caries

Dental caries is the most common, chronic, noncommunicable, preventable oral disease worldwide. Oxidation may play an important role in dental caries initiation and progression. Antioxidants in body fluids protect cells. The aim of this study was to evaluate salivary and serum total antioxidant capacity (TAC) and malondialdehyde (MDA) levels in dental caries. A total of 118 healthy caries-free and caries-active male and female students participated. Caries was detected clinically. Unstimulated whole-saliva samples and blood samples were obtained. Sialochemical analysis was carried out by spectrophotometric assay. Data were analyzed with the Student t test using STATA 11. Salivary and serum TAC levels in the case and control groups did not show any significant differences. Mean salivary MDA levels in the case and control groups were 0.71 ± 0.1 and 0.35 ± 0.06 nmol/mL, respectively. The results showed significantly higher levels of salivary and serum MDA in the case group compared to the healthy control group. The oxidative stress marker was significantly higher in the caries group compared to the healthy control group. Antioxidants were not significantly different between the two groups. MDA can be produced by dental caries, resulting in a decrease in antioxidant levels, causing disease progression. Further studies are necessary to determine whether MDA is the cause or effect of the disease.

Altered Salivary Profile in Heavy Smokers and its Possible Connection to Oral Cancer

Saliva is the first biological fluid to encounter inhaled cigarette smoke, whose numerous carcinogens and oxidants are responsible for the oral cancer so prevalent among smokers. Whole saliva, collected from 25 consenting heavy smokers and from a control group of 25 age- and gender-matched non-smokers, was subjected to sialochemical, biochemical, immunological and oxidative analyses. The mean flow rate was significantly higher in smokers than in non-smokers, as were the median activity value of superoxide dismutase (SOD) and the total salivary antioxidant capacity (ImAnOx) (by 32% and 12%, respectively, p=0.05). The salivary carbonyl concentration (an oxidative stress indicator) was significantly higher by 126% (p=0.0006) among smokers, while lactate dehydrogenase, albumin, total immunoglobulin G, and the metalloproteinases MMP-2 and MMP-9 concentrations were significantly lower in the smokers, by 86% (p=0.003), 65% (p=0.003), 61% (p=0.048), 35% (p=0.005) and 55% (p=0.035), respectively. Apparently, the oral cavity's salivary antioxidant system fails to cope with the severe attack of reactive oxygen species originating in cigarette smoke. Moreover, various other salivary functional and protective parameters also decreased among the smokers. Hence, further research aimed at examining the possibility of administration of agents as antioxidants or saliva substitutes to the oral cavity of smokers should be considered.

Oxidative Modification of Biomolecules in the Nonstimulated and Stimulated Saliva of Patients with Morbid Obesity Treated with Bariatric Surgery

Morbid obesity leads to progressive failure of many human organs and systems; however, the role of oxidative damage to salivary composition is still unknown in the obese patients. In this study, we assessed the effect of bariatric surgery on oxidative damage in nonstimulated (NS) and stimulated (S) whole saliva. The study included 47 subjects with morbid obesity as well as 47 age- and gender-matched healthy volunteers. Oxidative modifications to lipids (4-hydroxynonenal (4-HNE) and 8-isoprostanes (8-isoP)), proteins (advanced oxidation protein products (AOPP) and protein carbonyl groups (PC)), and DNA (8-hydroxy-D-guanosine (8-OHdG)) were analyzed in morbidly obese patients before and after bariatric surgery as well as in the healthy controls. The concentrations of 8-isoP, AOPP, PC, and 8-OHdG were significantly higher in both NS and S of patients with morbid obesity than in the control patients and compared to the results obtained 6 months after bariatric surgery. The levels of oxidative damage markers were also higher in S versus NS of morbidly obese patients. In summary, morbid obesity is associated with oxidative damage to salivary proteins, lipids, and DNA, while bariatric treatment generally lowers the levels of salivary oxidative damage.

Ability of salivary biomarkers in the prognostic of systemic and buccal inflammation

Nowadays, there is a growing interest in using saliva as an alternative sample for the diagnosis, prediction and progression of several diseases. It has been established that some molecules found in saliva are related to oral inflammatory processes and systemic health status. Furthermore, it is known that saliva is crucial for the carrying out of different functions in the oral cavity and its role in the local modulation of inflammatory and immune response is being thoroughly studied by the health research community. The aim of this review is to analyze the most important biomarkers which have been utilized in biomedicine during the last two decades in order to establish a correlation between certain specific salivary biomarkers and systemic inflammation. Then, we discuss the utility of total proteins, immunoglobulin A and alpha-amylase as biomarkers for the prognostic of local inflammation after oral surgery.

Key words:Inflammation, salivary biomarkers, systemic disease, buccal surgery, total proteins, inmunoglobulin A, Alpha-amylase.

Evaluation of Salivary and Serum Antioxidant and Oxidative Stress Statuses in Patients with Chronic Periodontitis: A Case-Control Study

Aim: Local bacteria stimulate polymorphonuclear neutrophils to release reactive oxygen species in periodontitis. Increased levels of oxidative stress play a significant role in the pathogenesis of periodontitis. Therefore, this study aimed to evaluate total salivary and serum antioxidant capacity and malondialdehyde in patients with chronic periodontitis.

Materials and methods: Fifty-five healthy subjects and 55 patients with chronic periodontitis, with an age range of 30–50 years, were evaluated. After clinical examination and case selection, unstimulated whole saliva was collected in the morning. Blood samples were taken from the antecubital vein. Total antioxidant capacity and malondialdehyde levels were evaluated by spectrophotometric assay. Data were analyzed with t-test, using Stata.11 software program.

Results: The periodontitis group exhibited lower salivary (0.16) and serum (0.36) total antioxidant capacity (P = 0.11) compared to the control group. Mean salivary malondialdehyde levels in the case and control groups were 0.80 ± 0.09 and 0.42 ± 0.08, respectively. The results showed significantly higher levels of salivary and serum malondialdehyde in the periodontitis group. Gender did not have any effect on antioxidant and oxidative stress levels.

Conclusion: This study indicated increased levels of salivary and serum oxidative stresses in patients with chronic periodontitis. Total antioxidant capacity was mildly lower in the saliva and serum of these patients. Higher malondialdehyde levels with no changes in antioxidant status can result in systemic and local complications in these patients.

Intermittent Hypoxia and Unsaturated Aldehydes: Effects on Oral Epithelial Wound Healing

Obstructive sleep apnea (OSA) is a highly prevalent sleep breathing disorder characterized by intermittent hypoxia (IH), leading to blood hypoxemia, hypercapnia, and sleep fragmentation. Studies on the effects of OSA on oral epithelial tissue healing are limited. Smoking is considered a risk factor for OSA through the exposure to chemically active toxins, present in the smoke. Acrolein is the most chemically active unsaturated aldehyde, impairing a variety of biological processes. The aim of this study was to determine the effect of IH on oral epithelial tissue healing, with and without acrolein. HaCaT cells were wounded by a cross-scratch made in the cell cultures, considered as time zero. Then, cells were exposed to 28 IH cycles (5-20% oxygen) during 12 h using the BioSpherix OxyCycler-C42 system. Control cells were maintained in normoxic conditions or in sustained hypoxia (SH) (5% oxygen) for the same durations, after which all cells were maintained for additional 12 h in normoxia. The migrating abilities of cells were measured after 24 h by calculating the percent of the residual cross-scratch area. In parallel experiments, 25 μM acrolein were added to each treatment. We found that the scratch closure was the slowest under IH. After 24 h, the residual scratch area in the IH treated cells was 29.5 ± 13.4% of the initial area, while in normoxia and SH it was 9.2 ± 5.8% and 10.3 ± 11.3%, respectively (p < 0.01 for both vs. IH). Adding acrolein further attenuated the migratory ability in IH as compared to normoxia and SH. We conclude that IH delays the healing process of oral epithelial tissue by slowing the cells' migratory abilities. The healing might be further attenuated by chemically active unsaturated aldehydes such as acrolein.

Acrolein-an α,β-Unsaturated Aldehyde: A Review of Oral Cavity Exposure and Oral Pathology Effects

Acrolein is a highly reactive unsaturated aldehyde widely present in the environment, particularly as a product of tobacco smoke. Our previous studies indicated the adverse consequences of even short-term acrolein exposure and proposed a molecular mechanism of its potential harmful effect on oral cavity keratinocytic cells. In this paper we chose to review the broad spectrum of acrolein sources such as pollution, food, and smoking. Consequently, in this paper we consider a high level of oral exposure to acrolein through these sources and discuss the noxious effects it has on the oral cavity including on salivary quality and contents, oral resistance to oxidative stress, and stress mechanism activation in a variety of oral cells.

Salivary stress biomarkers of recent nicotine use and dependence

BACKGROUND

Although stress plays a critical role in vulnerability to nicotine use and dependence, the stress response factors that contribute to smoking behaviors remain poorly elucidated. To minimize the confounding effects of chronic nicotine use, assessing individuals with relatively short smoking histories is critical for characterizing the neurobiological substrates associated with nicotine dependence early in the course of illness.

OBJECTIVES

This pilot study examined sympathetic nervous system (alpha-amylase) and hypothalamic-pituitary-adrenal axis (cortisol, dehydroepiandrosterone) responses to the Trier Social Stress Test (TSST) in young adult smokers. Associations among objective indices of recent smoking (salivary cotinine, carbon monoxide in the breath [CO]), behavioral measures of nicotine dependence and withdrawal, and salivary biomarkers in response to the TSST were investigated.

METHODS

Smokers (N = 64; 28 males, 36 females) provided saliva samples at 30 min intervals for 2 h prior to the TSST and every 10 min for 1 h following the TSST.

RESULTS

Alpha-amylase responses to the TSST were positively associated with salivary cotinine levels but negatively associated with CO levels. Individuals with a lower level of nicotine dependence had increased cortisol responses to the stressor, whereas those with a higher level of nicotine dependence did not show any cortisol changes in response to the stressor.

CONCLUSIONS

These findings indicate that different mechanisms may be involved at different levels of nicotine dependence severity. Recent nicotine use and lower dependence severity may be associated with increased activation of the stress response systems. In contrast, more severe levels of dependence may downregulate stress response systems.

Alternations of salivary antioxidant enzymes in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with chronic systemic inflammation. Oxidative stress may play a role in the pathogenesis of SLE. An increase in free radicals or an impaired antioxidant defense system in SLE causes oxidative stress. Therefore, oxidative damage plays an important role in the pathogenesis of SLE. Variations in antioxidant activity have been previously studied in serum of patients with this disease. However, salivary factors have not been evaluated. Considering that saliva, the noninvasive biological fluid, could be a reflection of the state of health, the purpose of this study was evaluation of peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activity in the saliva of patients with SLE. During the course of the practical part of the project, 30 patients with SLE and 30 healthy controls were selected to donate their saliva samples. After centrifugation of un-stimulated saliva, biological activity of POD, CAT and SOD were evaluated on their appropriate substrates using spectrophotometric methods and the results were statistically analyzed. The results showed that activities of antioxidant enzymes SOD and CAT were significantly reduced in saliva of SLE patients as compared to controls. The results suggest that antioxidant status was impaired in the saliva of SLE patients, and antioxidant status of saliva could be one of the non-invasive markers for SLE.

Oxidative stress in the oral cavity: sources and pathological outcomes

Oxidative stress (OS), an imbalance in the oxidant-antioxidant equilibrium, is thought to be involved in the development of many seemingly unrelated diseases. Oral cavity tissues are a unique environment constantly exposed to internal and external compounds and material hazards as almost no other part of the human body. Some of the compounds are capable of generating OS. Here, the main groups of endogenous as well as exogenous OS sources are presented, followed by their oxidative effect on the salivary contents and function. The oxidative mechanisms in oral cells and their pathologic influence are also discussed.

Oxidative stress and lung function profiles of male smokers free from COPD compared to those with COPD: a case-control study

BACKGROUND

The mechanisms of smoking tobacco leading to chronic obstructive pulmonary disease (COPD) are beginning to be understood. However, conclusions about the role of blood or lung oxidative stress markers were disparate.

AIMS

To investigate the oxidative stress in blood or lung associated with tobacco smoke and to evaluate its effect on pulmonary function data and its relation with physical activity.

METHODS

It is a case-control study. Fifty-four male-smokers of more than five pack-years (PY) and aged 40-60 years were included (29 Non-COPD, 16 COPD). Physical activity score was determined. Blood sample levels of malondialdehyde (MDA), protein-cys-SH (PSH), and Glutathione (GSH) were measured. Fractional exhaled nitric oxide (FeNO) and plethysmographic measurements were performed. Correlation coefficients (r) evaluated the association between oxidative stress markers and independent variables (plethysmographic data and physical activity score).

RESULTS

Non-COPD (48 ± 6 years) and COPD (49 ± 5 years) groups had similar tobacco consumption patterns, that is, 27 ± 14 PY versus 30 ± 19 PY, respectively. Compared to the Non-COPD group, the COPD group had significantly lower levels of GSH and PSH, that is, mean ± SE were 40 ± 6 versus 25 ± 5 µg/mL and 54 ± 10 versus 26 ± 5 µg/g of hemoglobin, respectively. However, MDA level and FeNO values were similar. In the COPD group, none of the oxidative stress markers was significantly correlated with plethysmographic data or physical activity score. In the Non-COPD group, GSH was significantly correlated with physical activity score (r = 0.47) and PSH was significantly correlated with total lung capacity (TLC) (r = -0.50), residual volume (r = 0.41), and physical activity score (r = 0.62). FeNO was significantly correlated with TLC of the COPD group (r = -0.48).

CONCLUSION

Compared to the Non-COPD group, the COPD group had a marked decrease in blood antioxidant markers (GSH and PSH) but similar blood oxidant (MDA) or lung (FeNO) burden.

Oxidative damage in keratinocytes exposed to cigarette smoke and aldehydes

Cigarette smoke (CS) is a significant environmental source of human exposure to chemically active saturated (acetaldehyde) and α,β-unsaturated aldehydes (acrolein) inducing protein carbonylation and dysfunction. The exposure of oral tissues to environmental hazards is immense, especially in smokers. The objectives of the current study were to examine the effect of aldehydes originating from CS on intracellular proteins of oral keratinocytes and to observe the antioxidant response in these cells. Intracellular protein carbonyl modification under CS, acrolein and acetaldehyde exposure in the HaCaT keratinocyte cell line, representing oral keratinocytes was examined by Western blot. Possible intracellular enzymatic dysfunction under the above conditions was examined by lactate dehydrogenase (LDH) activity assay. Oxidative stress response was investigated, by DCF (2,7-dichlorodihydrofluorescein) assay and GSH (glutathione) oxidation. Intracellular protein carbonyls increased 5.2 times after CS exposure and 2.7 times after exposure to 1 μmol of acrolein. DCF assay revealed an increase of fluorescence intensity 3.2 and 3.1 times after CS and acrolein exposure, respectively. CS caused a 72.5% decrease in intracellular GSH levels compared to controls. Activity of intracellular LDH was preserved. α,β-Unsaturated aldehydes from CS are capable of intracellular protein carbonylation and have a role in intracellular oxidative stress elevation in keratinocytes, probably due to the reduction in GSH levels.

LDH enzyme activity in human saliva: the effect of exposure to cigarette smoke and its different components

OBJECTIVE

Aldehydes and reactive nitrogen species (RNS) are important chemically active agents in cigarette smoke (CS). Salivary lactate dehydrogenase (LDH) originates predominantly from oral epithelium and was identified as an oral state marker. Its activity in saliva decreases after CS exposure. The aims of the current study were to identify the specific damaging agents in CS responsible for this activity reduction and to understand the mechanisms participating in CS oxidative damage to the salivary enzymes.

METHODS

Purified and salivary LDH samples were exposed to different levels of CS, pure acrolein, acetaldehyde, peroxynitrite and RNS donors. Each response of the isolated agent to the exposure was examined by a spectrophotometric enzyme activity assay and a Western blot.

RESULTS

CS exposure caused a 34% reduction in LDH activity. Isolated treatment with unsaturated-aldehydes (acrolein, 10μmol) caused a 61% reduction, while saturated-aldehydes (acetaldehyde, 200μmol), peroxynitrite (200μM) and RNS donor (SIN-1, 2mM) caused no substantial effect. All five LDH isoenzymes reacted similarly. The carbonyl immunoblotting assay revealed a fourfold increase in carbonyl content when treated with CS and a sevenfold increase when treated with acrolein.

CONCLUSION

α,β-Unsaturated-aldehydes were identified as the main CS ingredient responsible for salivary LDH activity diminution. The effect of saturated-aldehydes and RNS donors was negligible. Unsaturated-aldehydes are capable of introducing carbonyl group into proteins, causing their dysfunction. This provides a molecular explanation for a decrease in LDH enzymatic activity in saliva.

Time and dose effects of cigarette smoke and acrolein on protein carbonyl formation in HaCaT keratinocytes

Cigarette smoke (CS) is an important environmental source of human exposure to a highly toxic and chemically active α,β-unsaturated aldehyde: acrolein. It is capable of causing protein carbonylation and dysfunction, especially in oral tissues of smokers, constantly exposed to CS toxic constituents. The foremost damage is considered to be cumulative, but even a short exposure can be potentially harmful. The objectives of the current study were to examine the short time and dose effects of direct CS and acrolein exposure on intracellular protein carbonylation in epithelial cells. HaCaT-keratinocytes were exposed to different doses of acrolein and whole phase CS using a unique smoking simulator apparatus that mimics the exposure in smokers. The rate of intracellular protein carbonyl modification was examined 10-60 min after the exposure by Western blot. In addition, the effect of pre-incubation with a thiol scavenger N-acetylcysteine (NAC) was also assessed. We found that intracellular protein carbonyls increased as fast as 10 min after CS exposure and their concentration doubled after 20 min, with a slight elevation afterwards. Also, carbonyl levels increased gradually as CS and acrolein doses were elevated. Addition of 1 mM NAC neutralized part of the damage. We conclude that CS and acrolein intracellular protein carbonylation is dose- and time- dependent. Even a short time exposure to CS and its aldehydic constituents can be potentially harmful.

Salivary defense system alters in vegetarian

PURPOSE

The aim of this research was investigating antimicrobial and enzymatic antioxidant activities in salivary fluids of vegetarians as compared to normal subjects.

MATERIAL & METHODS

Antimicrobial activity of the saliva samples was evaluated against four clinically important bacteria. The biological activities of three of the main antioxidant enzymes of saliva were measured using appropriate methods of enzyme assay in both groups.

RESULTS

According to the results, saliva obtained from vegetarians showed a reduced inhibitory effect on growth of Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa and Escherichia coli as compared to those obtained from the non-vegetarian subjects. The activity of salivary peroxidase, catalase and superoxide dismutase showed a statistically marked decrease in vegetarian group.

CONCLUSIONS

According to our literature survey, this is the first report on the antibacterial and antioxidant capacity in saliva of vegetarians. Results obtained from the present study have opened a new line of research with the basis of saliva as a research tool.

Role of lipid oxidation, chelating agents, and antioxidants in metallic flavor development in the oral cavity

This study investigated the production of metallic flavor, which is a combination of taste and retronasal odor. Chemical reactions in the oral cavity and saliva of healthy subjects were investigated after ingesting iron and copper solutions above and near threshold levels. Significant increase in lipid oxidation (p < 0.001) occurred after metal ingestion, detected as TBARS values. Ferrous ion caused the greatest flavor sensation and lipid oxidation, followed by cupric and cuprous ions. Ferric ion did not cause metallic sensation. Occurrence of oxidation was supported by damage to salivary proteins, detected as protein-carbonyls, and by a significant increase of odorous lipid oxidation related aldehydes. Sensory evaluation demonstrated that antioxidants (vitamins E and C) minimally reduced metallic flavor but that chelating agents (EDTA and lactoferrin) removed the metallic flavor. The role of lipid oxidation is essential for the production of a metallic flavor from ingestion of ferrous, cupric, and cuprous ions.

EGF in saliva and tumor samples of oral squamous cell carcinoma

The objective of this research was to investigate the salivary levels of epidermal growth factor (EGF) in patients with oral squamous cell carcinoma (OSCC) in comparison with clinically healthy individuals and to verify the immunoexpression of EGF in tumor samples. In addition, the relationship between salivary levels and tumoral EGF expression with clinicopathologic features was investigated. We carried out an investigation on EGF expression in lesion samples and in saliva of OSCC patients through immunohistochemistry and enzyme-linked immunosorbent assay, respectively. EGF salivary levels of OSCC patients were also compared with levels in saliva of healthy controls. EGF levels were significantly lower in OSCC patients in comparison with the control group. Smoking, tumor location, and alcohol consumption affected salivary levels of EGF. Strong immunoexpression of EGF was associated with a more aggressive histologic pattern of the lesion. There was no significant association among salivary levels and immunohistochemical expression of EGF. Although EGF expression is frequently observed in tumors, salivary levels of EGF are reduced in patients with OSCC samples. Tobacco and alcohol may decrease EGF in saliva, which may contribute to oral carcinogenesis. Indeed, further investigations are needed to elucidate the EGF pathways.

Green tea: a promising natural product in oral health

Green tea is a leading beverage in the Far East for thousands of years; it is regarded for a long time as a health product. Green tea is important source of polyphenol antioxidants. Polyphenols including epigallocatechin 3 gallate (EGCG) constitute the most interesting components in green tea leaves. Green tea has the potential to protect against various malignant, cardiovascular and metabolic diseases. There is a growing body of evidence pointing a beneficial role of green tea and its polyphenols in oral health. Green tea protects against bacterial induced dental caries. Tea polyphenols possess antiviral properties, believed to help in protection from influenza virus. Additionally, green tea polyphenols can abolish halitosis through modification of odorant sulphur components. Oral cavity oxidative stress and inflammation, consequent to cigarette smoking and cigarettes' deleterious compounds nicotine and acrolein, may be reduced in the presence of green tea polyphenols. Generally, green tea defends healthy cells from malignant transformation and locally has the ability to induce apoptosis in oral cancer cells. All together, there is an increasing interest in the health benefits of green tea in the field of oral health. Nonetheless, there is still a need for more clinical and biological studies to support guidelines for green tea intake as part of prevention and treatment of specific oral pathologies.

Lipid patterns in the saliva of smoking young adults

Salivary lipids are important for the maintenance of oral cavity health. Elevated salivary lipid levels are associated with an increase of caries incidence, plaque development, calculus formation and periodontal disease. However, the regulation of lipid salivary levels is scarcely known. Cigarette smoke is considered a risk factor for oral cavity diseases. We study how cigarette smoke may affect the secretion of salivary lipids. To this purpose, we determine the salivary levels of cholesterol and of glycerolipids in saliva sampled from smokers and non-smokers at various times of day. We observe an increase of glycerophospholipid and a decrease of cholesterol levels in the smokers' saliva collected at 10 p.m. On the other hand, unsaturated fatty acids in chief phospholipids of saliva are lower in smokers at 7 a.m. Therefore, for the first time, we demonstrate that cigarette smoke induces variations of saliva lipid pattern in young people even moderately smoking.

Effects of cigarette smoke on salivary protein tyrosine nitration

INTRODUCTION

Nitration of tyrosine and tyrosine-containing proteins and their roles in pathophysiology have just recently been reviewed. Despite low yields of tyrosine modifications, nitration of tyrosine residues may inactivate important proteins. Nitrotyrosine can be formed by various nitrating agents, including peroxynitrite. Thus, the occurrence of nitrotyrosine-containing proteins in vivo should be regarded as a general indication of tissue damage induced by reactive nitrogen species such as peroxynitrite. This strongly suggests that peroxynitrite could be formed in vivo under certain pathophysiological conditions.

OBJECTIVE

Our aim in this study was to elucidate the effect of cigarette smoke (CS) on nitrotyrosine formation in saliva proteins.

METHODS

We exposed saliva to CS, in vitro, and used Western Blotting (WB) and monoclonal anti-nitrotyrosine antibody to assess the level of saliva protein nitration.

RESULTS

As saliva contains extensive amounts of nitrites, it was no surprise that at basal levels, saliva proteins, albumin, and α-amylase all were already nitrated. The WB also revealed that with continuous exposure to CS the tyrosine nitration of both albumin and α-amylase is declining significantly after 3 h. A quite similar effect was seen after exposure to aldehydes, but to a less extent as compared to CS. Exposure of nitrotyrosine-modified bovine serum albumin (BSA-N) to aldehydes, produced a similar effect, meaning a decrease in tyrosine nitration.

CONCLUSIONS

These findings might be explained by the possible ability of CS aldehydes to reduce protein-bound nitro group to an amine. Another proposed mechanism is that CS unsaturated aldehydes react with proteins mainly through Michael addition reaction; leading to the generation of stable aldehyde-protein adducts (APA). Thus, it may react with nitro groups of saliva proteins, like albumin or α-amylase, to generate APA, which ultimately, may not be recognized by our antibody. Another possible mechanism, is interaction between the aldehyde group with the hydroxyl group of the 3-nitrotyrosine, forming a hemiacetal, which is not recognized by the antibody. This mechanism might explain the difference in the denitration effects caused by the saturated aldehyde acetaldehyde, which exists in large amounts in CS, and unsaturated aldehydes. Therefore, it is possible that the main player in the CS smoke denitration effect on salivary proteins is the aldehyde group and not the double bond of unsaturated aldehydes.

Influência do fumo na atividade da amilase salivar e na curva glicêmica

OBJETIVO: Determinar a atividade da amilase salivar e a relação com a glicemia, antes e após a ingestão de carboidratos em fumantes e não fumantes, uma vez que in vitro a exposição da saliva à fumaça do cigarro induz à redução da atividade da amilase salivar e poderia influenciar na absorção dos carboidratos da dieta. MÉTODOS: Foram avaliados voluntários fumantes (n=10) e não fumantes (n=10). Realizou-se coletas da saliva antes e após o fumo e determinou-se a glicemia antes e após a ingestão de 72g de carboidratos. Para glicemia usaram-se tempos de 0, 15, 30, 60, 120 minutos. A determinação da atividade da amilase salivar foi realizada por meio de kits comerciais. A glicemia foi determinada utilizando o aparelho Glicomiter (Accu-Chek-Roche). As análises estatísticas foram realizadas no software Sigmastat, utilizou-se o método Teste t pareado (p<0,05). RESULTADOS: O aumento da glicemia aos 15, 30, 60 e 90 minutos foi de 3,9; 11,9; 34,8 e 22,7% para os não fumantes e 4,9; 6,5; 13,8 e 9,7% para os fumantes, respectivamente. No pico máximo de absorção tem-se uma glicemia de 21,0 % maior nos pacientes não fumantes. A atividade da amilase salivar antes e após alimentação apresentou-se 75,0% menor nos indivíduos fumantes. CONCLUSÃO: Estes resultados sugerem que o fumo inibe a amilase e influencia na diminuição da digestão/absorção de carboidratos, consequentemente na concentração de glicose sanguínea, reduzindo assim o aporte energético ingerido.

Altered Salivary Redox Homeostasis in Patients with Systemic Sclerosis

Objective.

Oxidative stress has been implicated in the pathogenesis of systemic sclerosis (SSc). Our objective was to determine whether SSc is associated with altered redox homeostasis in human saliva.

Methods.

Study participants were 70 women with SSc and 120 female controls. 8-hydroxy-2’-deoxyguanosine (8-OHdG), 8-epi-prostaglandin F 2α (8-epi-PGF2α), and total protein carbonyls were assayed by ELISA to quantify oxidative damage to nucleic acids, lipids, and proteins, respectively, in whole nonstimulated saliva.

Results.

We observed a significantly positive association between salivary log protein carbonyls and SSc in a crude statistic (OR 9.06, p < 0.0001), and multivariable model adjusted for log 8-OHdG, log 8-epi-PGF2α, and antioxidant exposure (OR 9.26, p < 0.0001). No significant association was noted between SSc and salivary log 8-epi-PGF2α or log 8-OHdG.

Conclusion.

Salivary redox homeostasis is perturbed in patients with SSc and may inform on the pathophysiology and presence of the disease (biomarkers) and efficacy of therapeutic interventions.

Comparison of superoxide dismutase activity in saliva of smokers and nonsmokers

BACKGROUND

Considering the role of superoxide dismutase (SOD) as one of the most important salivary antioxidant enzymes, this study was performed to compare the level of this enzyme in smokers and nonsmokers.

METHODS

Unstimulated saliva of 60 volunteers (30 smokers and 30 nonsmokers) was collected. The activity of salivary SOD was measured in each group and compared.

RESULTS

The mean value of superoxide dismutase activity was significantly higher in the smoking group (P < 0.001), while no detectable activity level was found in nonsmokers.

CONCLUSION

Cigarette smoke leads to an elevation in salivary superoxide dismutase activity.

Effects of acute psychosocial stress on cigarette craving and smoking

INTRODUCTION

Stress is thought to influence use of drugs, including cigarette smoking, but the mechanisms by which it does so are not clear. In this study, we investigated the effects of acute psychosocial stress on cigarette craving, the subjective effects of smoking, and smoking behavior in daily smokers.

METHODS

Healthy male and female smokers participated in two experimental sessions in which they were exposed to the Trier Social Stress Test or a nonstressful control task. For 2 hr after each task, they had repeated opportunities to either smoke or earn money. Physiological (heart rate, cortisol, and alpha-amylase) and subjective (anxiety and desire to smoke) measures were obtained before and after the tasks and after each smoking opportunity.

RESULTS

Stress significantly increased cigarette craving but it did not increase smoking. When individual differences in nicotine dependence were taken into account, stress influenced CO boost and pleasure from smoking the first cigarette.

DISCUSSION

Our results support previous evidence that acute psychosocial stress increases smoking desire.

Neuroendocrine and psychometric evaluation of a placebo version of the 'Trier Social Stress Test'

The "Trier Social Stress Test" (TSST) is one of the most prominent laboratory stress paradigms. It is often used to investigate the effects of stress on cognitive or affective parameters. Such studies need a non-stress control condition. However, control conditions currently employed are often rather ill defined and do not parallel important modulating variables, e.g., physical or cognitive load of the TSST. We here introduce a placebo version of the TSST, which contains a free speech and a simple mental arithmetic task without uncontrollability and social-evaluative threat. In two studies, this control condition was evaluated using salivary markers of stress reactivity (cortisol and alpha-amylase) and a questionnaire for anticipatory cognitive stress appraisal (PASA). In experiment 1 participants who were treated with the placebo condition showed no cortisol response and a small, but significant salivary alpha-amylase (sAA) response. Both responses were significantly smaller than those of TSST-treated participants. The placebo-treated participants also rated the treatment situation as less stressful. In experiment 2 a crossover study with the use of an intercom to instruct the participants and ensure their compliance was conducted. Again there was a strong cortisol response to the TSST, which differed significantly from the cortisol levels observed during the placebo condition. Importantly the cortisol response was not influenced by treatment order (TSST or placebo first). However, in this study we found similar reactions between TSST- and placebo-treated participants with regard to sAA-response. We suggest that the introduced placebo protocol for the TSST is a promising tool for future psychobiological research. The exact procedure for a given experiment should be tailored to the specific needs of the empirical question studied.

Determinants of salivary alpha-amylase in humans and methodological considerations

Salivary alpha-amylase (sAA) has been proposed as a marker for activity of the sympathetic nervous system (SNS). Recent studies in support of this hypothesis have led to an increased number of researchers integrating amylase measurements into their study designs. Salivary alpha-amylase is produced locally in the salivary glands, controlled by the autonomic nervous system. This entails some methodological consequences and potential pitfalls that might lead to increased error variance and thus prevent successful testing of hypotheses. The goal of this review is to summarize basic and recent findings on methodological issues and potential factors influencing sAA measurement, and to derive a set of recommendations enabling researchers to successfully using sAA in psychoneuroendocrinological experiments.

Screening for periodontitis in pregnant women with salivary enzymes

AIM

To develop a test for the screening of pregnant women for periodontitis using saliva prior to a dental examination.

METHODS

A cross-sectional research design was employed. Whole unstimulated saliva was collected from 221 pregnant women prior to a dental examination at the Amagasaki Public Health Office and levels of activity of lactate dehydrogenase (LDH) and alkaline phosphatase (ALP), and of occult blood in the saliva were measured. The data were compared with Community Periodontal Index of Treatment Needs (CPITN) scores. The diagnostic performance of LDH, ALP, and occult blood was determined in terms of sensitivity, specificity, and the area under receiver operating characteristics (ROC) curves. The optimal combination of parameters for screening periodontitis was determined at maximum sensitivity and specificity.

RESULTS

Periodontitis (CPITN 3, 4) in 19 women (8.6%) and gingivitis (CPITN 1, 2) in 129 women (58.4%) were observed. The activity levels of LDH and ALP were significantly higher in the pregnant women with periodontitis than those with gingivitis or a healthy periodontium. To distinguish between the pregnant women with periodontitis and the others, a cut-off value of 684 IU/L for LDH and of 75 IU/L for ALP were determined by a ROC analysis. The test combining LDH, ALP, and occult blood showed the highest diagnostic performance; with a sensitivity value of 0.90, specificity value of 0.62, positive predictive value of 0.18, and negative predictive value of 0.98.

CONCLUSIONS

A test combining the parameters salivary LDH, ALP and occult blood is useful for screening pregnant women for periodontitis.

Diurnal variations in salivary protein carbonyl levels in normal and cognitively impaired human subjects

Oxidative stress has been documented in tissues and biofluids of subjects with sporadic Alzheimer disease (AD) and mild cognitive impairment (MCI). The aim of this study was to determine whether (a) salivary protein carbonyls are elevated in AD and MCI subjects, (b) salivary protein carbonyl contents in these groups exhibit diurnal variation, and (c) apolipoprotein E epsilon 4 (apoE epsilon 4) carrier status impacts salivary carbonyl concentrations or rhythmicity in the AD and MCI cohorts. Unstimulated saliva was collected at fixed intervals between 8 AM: and 10 PM: from 15 AD subject , 21 MCI subjects, and 30 cognitively-intact controls. Salivary protein carbonyl concentrations were measured by ELISA. ApoE genotyping was performed on the AD and MCI individuals. For all groups, mean protein carbonyl contents were significantly elevated at 2 PM: relative to other time points surveyed. Mean salivary protein carbonyl concentrations did not differ among the diagnostic groups. ApoE epsilon 4 carriers exhibited less temporal variation in salivary protein carbonyls relative to noncarriers. Thus, protein carbonyl content exhibits diurnal variation in adult human saliva. ApoE epsilon 4 carrier status may impact oropharyngeal disease expression by attenuating the inherent diurnal variability in salivary redox homeostasis. Salivary protein carbonyls do not differentiate AD and MCI from normal individuals. In conclusion, oxidative stress has been documented in tissues and biofluids of subjects with sporadic AD and MCI. This article demonstrates that levels of protein carbonyls, a marker of oxidative stress, exhibit robust diurnal variation in the saliva of normal elderly, MCI, and AD subjects. Apolipoprotein E epsilon 4 allele carrier status may attenuate this temporal variability in salivary redox homeostasis and thereby impact the natural history of oropharyngeal diseases.

No effect of cigarette smoking dose on oxidized plasma proteins

Cigarette smoking is a major source of oxidative stress. Protein carbonyls have been used as a biomarker of oxidative stress because of the relative stability of carbonylated proteins and the high protein concentration in blood. Increased levels of carbonyl groups have been found in serum proteins of smokers compared to nonsmokers. However, neither the dose effect of current cigarette smoke nor other predictors of oxidative stress have been studied. Hence, we used an Enzyme-Linked Immunosorbent Assay (ELISA) to evaluate plasma protein carbonyls in smokers recruited in the Early Lung Cancer Action Project (ELCAP) program. The lung cancer screening program enrolled current and former smokers age 60 years and over without a prior cancer diagnosis. A total of 542 participants (282 men and 260 women) completed a baseline questionnaire and provided blood samples for the biomarker study. Protein oxidation was measured by derivatization of the carbonyl groups with 2,4-dinitrophenylhydrazine (DNPH) and ELISA quantitation of the DNPH group. Current smoking status was confirmed with urinary cotinine. The mean (+/-S.D.) protein carbonyl level was 17.9+/-2.9 nmol carbonyl/ml plasma. Protein carbonyls did not differ significantly by gender. Carbonyl levels were higher among current than former smokers, but these differences did not attain statistical significance, nor did differences by urine cotinine levels, pack-years, pack/day among current smokers, and smoking duration. In a multiple regression analysis, higher protein carbonyl levels were independently associated with increasing age (0.59 nmol/ml increase per 10 years, 95% CI 0.14, 1.05, p=0.01), African-American vs. white race/ethnicity, (1.30 nmol/ml, 95% CI 0.4, 2.19, p=0.008), and lower educational attainment (0.75 nmol/ml, 95% CI 0.12, 1.38, p=0.02). Although we found no significant difference between current vs. past cigarette smoking and protein carbonyls in this older group of smokers, associations were found for age, ethnicity, and educational attainment. Our results indicate that the measurement of plasma carbonyls by this ELISA technique is still an easy and suitable method for studies of diseases related to oxidative stress.

Cigarette smoke effect on total salivary antioxidant capacity, salivary glutathione peroxidase and gamma-glutamyltransferase activity

Saliva is the first biological fluid that inhaled cigarette smoke (CS) encounters. CS contains several carcinogens known to initiate and promote tumourigenesis and metastasis. One of the aims of this study was to establish if glutathione peroxidase and gamma-glutamyltranspherase (GGT) could be used as possible markers for evaluating the oral oxidative stress caused by smoking. The effect of CS on free radical generation was investigated using two methods. Using different assays, different antioxidants present in saliva may be evidenced due to the different principles on which they are based. Our results indicate that exposure to CS caused a statistically significant decrease of both salivary glutathione peroxidase (p < 0.01) and salivary GGT (p < 0.01). We also found that exposure to CS caused a statistically significant decrease of salivary total antioxidant status (p < 0.01). Such decreases may have a consistent role in the mechanisms by which the toxic effects of CS initiate oral inflammatory diseases, promote precancerous transformations, and destroy the oral cavity homeostasis. Therefore the evaluation of total antioxidant capacity of saliva is important but it must be done together with the evaluation of salivary specific markers of oxidative stress, such as uric acid, albumin and possibly, GGT.

Age-related changes in salivary antioxidant profile: possible implications for oral cancer

Oral cancer's much higher prevalence among older people may be due to an age-related reduction in protective salivary antioxidant mechanisms and/or an age-related increase in the magnitude of oral carcinogen attack, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), causing DNA aberrations. This study found a significantly reduced total value of salivary antioxidant capacity in elderly persons (as measured by overall antioxidant capacity [ImAnOx] assay), (46% of healthy individuals, p =.004), increased oxidative stress (86% increase in carbonyl concentrations--indicators of enhanced ROS attack, p =.001), and increased salivary concentrations and total values of RNS (7-fold and 3-fold higher respectively, p =.001), all contributing to increased DNA oxidation of oral epithelial cells. Salivary oxidative stress-related changes in the intimately related saliva and oral epithelium compounded with higher viscosity of saliva may explain the higher prevalence of oral cancer in the elderly population. Administration of local therapeutic agents (i.e., antioxidants) to the oral cavity should be considered.

Longitudinal Study of the Association Between Smoking as a Periodontitis Risk and Salivary Biomarkers Related to Periodontitis

BACKGROUND

Insufficient data exist regarding the long-term influence of lifestyle factors including smoking on periodontal health. The objective of this study was to examine the prospective association between smoking and periodontal disease progression and the effects of smoking on salivary biomarkers related to periodontitis.

METHODS

Probing depth (PD) was measured at health checkups of workers in 1999 and 2003; additionally, lifestyle information was obtained through a questionnaire. In 2003, 219 of 256 (86%) workers examined at baseline completed PD measurements; saliva samples were also collected. Change in PD was used for assessment of periodontitis progression when three or more sites displayed an increase of >or=2 mm over 4 years. Salivary biomarker levels were determined by real-time polymerase chain reaction and enzyme assay. Statistical methods included bivariate and multivariate regression analyses.

RESULTS

In the multiple logistic model, in which lifestyle-related factors served as independent variables, significant variables were current smoking and hours of sleep; respective odds ratios were 2.3 and 2.1. Additionally, 38.5% of periodontal disease progression was attributable to current smoking. Moreover, pack-years of smoking showed a dose-response relationship with disease progression. Levels of salivary markers including prostaglandin E(2), lactoferrin, albumin, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase were significantly lower in current smokers than in non-current smokers. However, no meaningful differences in the proportions of six periodontal pathogens were observed between current and non-current smokers.

CONCLUSIONS

Smoking exerted the greatest influence on periodontitis risk among lifestyle factors. Smoking may suppress the host-defense system, which may promote periodontal disease progression.

Determinants of the diurnal course of salivary alpha-amylase

OBJECTIVE

Previous data from our group and others have shown that salivary alpha-amylase activity increases in response to stress. It has been suggested that salivary alpha-amylase may be a marker for adrenergic activity. Less is known about other determinants of salivary alpha-amylase activation. The objective of the current study was to describe the diurnal pattern of salivary amylase and its determinants.

METHODS

Saliva samples were collected immediately after waking-up, 30 and 60 min later, and each full hour between 0900 and 2000 h by 76 healthy volunteers (44 women, 32 men). Compliance was controlled by electronic monitors. In order to control factors which might influence the diurnal profile of salivary alpha-amylase (such as momentary stress, mood, food, or body activity), at each sampling time point the subjects filled out a diary examining the activities they had carried out during the previous hour.

RESULTS

Salivary alpha-amylase activity shows a distinct diurnal profile pattern with a pronounced decrease within 60 min after awakening and a steady increase of activity during the course of the day. Mixed models showed a relative independence of diurnal salivary alpha-amylase from momentary stress and other factors, but significant associations with chronic stress and mood.

CONCLUSIONS

Our results suggest that diurnal profiles of salivary alpha-amylase are relatively robust against momentary influences and therefore may prove useful in the assessment of sympathetic nervous system activity. The findings underscore the need to control for time of day in studies using salivary alpha-amylase as a dependent variable.