Inhibition of oral peroxidase activity by cigarette smoke: in vivo and in vitro studies

The Impact of Nicotine Patches on Gingival and Oral Health: A Narrative Review

Smoking significantly impacts oral health, causing periodontal disease, oral cancer, tooth discoloration, halitosis, and impaired wound healing. Nicotine replacement therapy (NRT), particularly nicotine patches, is widely used for smoking cessation. This review evaluates the literature regarding nicotine patches and their implications for oral and gum health. Nicotine patches deliver controlled nicotine doses transdermally, alleviating cravings and withdrawal symptoms. While nicotine can negatively affect oral health through vasoconstriction and reduced salivary flow, the overall impact of patches is generally positive compared to continued smoking. The primary benefit is the elimination of exposure to harmful chemicals and heat from cigarette smoke, significantly decreasing oral cancer risk and periodontal disease progression. Nicotine patches are associated with improved periodontal treatment outcomes, better wound healing, and potential anti-inflammatory effects. They may also promote improved oral hygiene practices. However, limitations include uncertain long-term effects and potential side effects like xerostomia. In conclusion, while nicotine patches may have some oral health effects, their use generally leads to significant improvements compared to continued smoking, making them valuable for promoting better oral health in individuals quitting smoking.

Applications of Antioxidants in Dental Procedures

As people are paying more and more attention to dental health, various dental treatment procedures have emerged, such as tooth bleaching, dental implants, and dental restorations. However, a large number of free radicals are typically produced during the dental procedures. When the imbalance in distribution of reactive oxygen species (ROS) is induced, oxidative stress coupled with oxidative damage occurs. Oral inflammations such as those in periodontitis and pulpitis are also unavoidable. Therefore, the applications of exogenous antioxidants in oral environment have been proposed. In this article, the origin of ROS during dental procedures, the types of antioxidants, and their working mechanisms are reviewed. Additionally, antioxidants delivery in the complicated dental procedures and their feasibility for clinical applications are also covered. Finally, the importance of safety assessment of these materials and future work to take the challenge in antioxidants development are proposed for perspective.

Ethanol- and Cigarette Smoke-Related Alternations in Oral Redox Homeostasis

Alcohol abuse as well as smoking cigarettes has been proven to negatively affect the oral environment. The aim of this work was to provide a systematic review of the literature on the influence of ethanol and cigarette smoking on oral redox homeostasis. A search was performed for scientific articles indexed in the PubMed, Medline and Web of Science databases. We identified 32,300 articles, of which 54 were used for the final review, including the results from 2000 to 2021. Among the publications used to write this article, n = 14 were related to the influence of alcohol consumption (clinical studies n = 6, experimental studies n = 8) and n = 40 were related to the influence of smoking (clinical studies n = 33, experimental studies n = 7) on oral redox homeostasis. The reviewed literature indicates that alcohol abusers and smokers are more likely to suffer from salivary gland dysfunction, as well as develop precancerous lesions due to DNA damage. Compared to alcohol abstainers and non-smokers, alcohol drinkers and smokers are also characterized by a deterioration in periodontal health measured by various indicators of periodontal status. In summary, alcohol abuse and smoking are associated with disrupted oral redox homeostasis, which may lead not only to tooth loss, but also contribute to various adverse effects related to mental health, digestive processes and chronic inflammation throughout the human body.

Role of Hydrogen Sulfide in Oral Disease

Oral diseases are among the most common human diseases yet less studied. These diseases affect both the physical, mental, and social health of the patients resulting in poor quality of life. They affect all ages, although severe stages are mostly observed in older individuals. Poor oral hygiene, genetics, and environmental factors contribute enormously to the development and progression of these diseases. Although there are available treatment options for these diseases, the recurrence of the diseases hinders their efficiency. Oral volatile sulfur compounds (VSCs) are highly produced in oral cavity as a result of bacteria activities. Together with bacteria components such as lipopolysaccharides, VSCs participate in the progression of oral diseases by regulating cellular activities and interfering with the immune response. Hydrogen sulfide (H2S) is a gaseous neurotransmitter primarily produced endogenously and is involved in the regulation of cellular activities. The gas is also among the VSCs produced by oral bacteria. In numerous diseases, H2S have been reported to have dual effects depending on the cell, concentration, and donor used. In oral diseases, high production and subsequent utilization of this gas have been reported. Also, this high production is associated with the progression of oral diseases. In this review, we will discuss the production of H2S in oral cavity, its interaction with cellular activities, and most importantly its role in oral diseases.

Salivary gland dysfunction and salivary redox imbalance in patients with Alzheimer's disease

Alzheimer’s disease (AD) is associated with the deposition of β-amyloid in the brain. AD accounts for over 50% of cases of dementia which results from disturbances in redox homeostasis. Indeed, increased intensity of protein oxidation and nitration as well as lipid peroxidation is observed in brain areas with considerable amounts of amyloid plaques and neurofibrillary tangles. However, little is known about the oxidoreductive balance of salivary glands in AD patients. Therefore, the aim of this study was to evaluate the antioxidant barrier and oxidative/nitrosative stress biomarkers in stimulated saliva and blood of AD patients. The study was participated by 25 AD patients and 25 non-demented controls without neurological diseases or cognitive impairment, matched by age and gender to the study group. The number of patients was determined based on a previous pilot study (test power = 0.9). We found a significant decrease in the activity of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), increased activity of catalase (CAT) and reduced concentration of plasma non-enzymatic antioxidants (uric acid, UA and reduced glutathione, GSH). In contrast, in the stimulated saliva of AD patients we observed significantly decreased activity of all antioxidant enzymes (SOD, CAT and GPx) as well as concentration of GSH compared to the control group. The content of lipid (malondialdehyde, MDA) and protein (advanced oxidation protein products, AOPP; advanced glycation end-products, AGE) oxidation products as well as biomarkers of nitrosative stress (peroxynitrite, nitrotyrosine) was significantly higher in both saliva and plasma of AD patients compared to the controls. In AD patients, we also observed a considerable decrease in stimulated saliva secretion and salivary total protein content, and an increase in salivary β-amyloid concentration. In conclusion, AD results in redox imbalance towards oxidative reactions, both at the level of the oral cavity and the entire body. General redox balance disturbances do not coincide with salivary redox balance disturbances. Reduction in stimulated saliva secretion in AD patients reflects secretory dysfunction of the parotid glands.

The Relationship Between Salivary Redox, Diet, and Food Flavor Perception

The mouth is the gateway for entrance of food and microorganisms into the organism. The oral cavity is bathed by saliva, which is thus the first fluid that food and microorganisms will face after their entrance. As a result, saliva plays different functions, including lubrication, predigestion, protection, detoxification, and even transport of taste compounds to chemoreceptors located in the taste buds. To ensure its function of protection, saliva contains reactive harmful compounds such as reactive oxygen species that are controlled and neutralized by the antioxidant activity of saliva. Several antioxidant molecules control the production of molecules such as reactive oxygen compounds, neutralize them and/or repair the damage they have caused. Therefore, a balance between reactive oxidant species and antioxidant compounds exists. At the same time, food can also contain antioxidant compounds, which can participate in the equilibrium of this balance. Numerous studies have investigated the effects of different food components on the antioxidant capacity of saliva that correspond to the ability of saliva to neutralize reactive oxygen species. Contradictory results have sometimes been obtained. Moreover, some antioxidant compounds are also cofactors of enzymatic reactions that affect flavor compounds. Recent studies have considered the salivary antioxidant capacity to explain the release of flavor compounds ex vivo or in vivo. This article aims to review the effect of food on the antioxidant capacity of saliva and the impact of salivary antioxidant capacity on flavor perception after a brief presentation of the different molecules involved.

Salivary Redox Biomarkers in the Course of Caries and Periodontal Disease

Caries are a pathological process of extracorporeal nature, characterized by demineralization of inorganic substances as well as proteolysis triggered by acids produced by bacteria present in dental plaque, as a result of metabolism of sugars of both external and internal origin. Periodontal disease, on the other hand, is a multifactorial degenerative disease associated with inflammation, involving a group of tissues that surround the dental cervix and root of the tooth. It is believed that one of the mechanisms in the etiopathogenesis of caries and periodontitis are disorders of local and/or general oxidative stress (OS) parameters. Numerous clinical studies have confirmed the relationship between oxidative stress markers and oral diseases. In most analyzed studies, technical and biological variability was so high that none of the markers so far has proven suitable for routine clinical use. The aim of systematic reviews of the literature is to present the existing studies on OS parameters, mainly concerning the activity of antioxidant enzymes in saliva of patients with caries and periodontitis.

Xanthine oxidase-lactoperoxidase system and innate immunity: Biochemical actions and physiological roles

The innate immune system in mammals is the first-line defense that plays an important protective role against a wide spectrum of pathogens, especially during early life before the adaptive immune system develops. The enzymes xanthine oxidase (XO) and lactoperoxidase (LPO) are widely distributed in mammalian tissues and secretions, and have a variety of biological functions including in innate immunity, provoking much interest for both in vitro and in vivo applications. The enzymes are characterized by their generation of reactive oxygen and nitrogen species, including hydrogen peroxide, hypothiocyanite, nitric oxide, and peroxynitrite. XO is a major generator of hydrogen peroxide and superoxide that subsequently trigger a cascade of oxidative radical pathways, including those produced by LPO, which have bactericidal and bacteriostatic effects against pathogens including opportunistic bacteria. In addition to their role in host microbial defense, reactive oxygen and nitrogen species play important physiological roles as second messenger cell signaling molecules, including cellular proliferation, differentiation and gene expression. There are several indications that the reactive species generated by peroxide have positive effects on human health, particularly in neonates; however, some important in vivo aspects of this system remain obscure. The primary dependence of the system on hydrogen peroxide has led us to propose it is particularly relevant to neonate mammals during milk feeding.

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Male Smokers

BACKGROUND

Cigarette smoke free radicals can cause cellular damage and different diseases. All the body fluids have antioxidants which protect against free radicals.

OBJECTIVE

The aim of this study was to evaluate salivary total antioxidant capacity and peroxidase, uric acid and malondialdehyde levels in smokers and a nonsmoking control group.

METHODS

Unstimulated saliva was collected from 510 males. A total of 259 subjects were current smokers and 251 were non-smokers. The levels of salivary total antioxidant capacity, uric acid, peroxidase and malondialdehyde were measured using standard procedures. Data were analyzed with t test and ANOVA.

RESULTS

The smokers were younger and dental hygiene index was higher than healthy nonsmoking controls. The mean total antioxidant capacity in smokers and nonsmokers was 0.13±0.07 and 0.21±011, respectively (P=0.001). Smokers had significantly lower peroxidase and uric acid levels than healthy controls. In addition, the mean malondialdehyde levels in the smokers and nonsmokers were 4.55 ±2.61 and 2.79 ±2.21, respectively (P=0.001).

CONCLUSION

Cigarette smoke produces free radical and oxidative stress, causing many side effects. Salivary antioxidant levels decreased and malondialdehyde levels increased in smokers, indicating the high oxidative stress among smokers compared to nonsmokers. Cigarette smoke had deleterious effects on main salivary antioxidants levels.

Tobacco exposure associated with oral microbiota oxygen utilization in the New York City Health and Nutrition Examination Study

PURPOSE

The effect of tobacco exposure on the oral microbiome has not been established.

METHODS

We performed amplicon sequencing of the 16S ribosomal RNA gene V4 variable region to estimate bacterial community characteristics in 259 oral rinse samples, selected based on self-reported smoking and serum cotinine levels, from the 2013-2014 New York City Health and Nutrition Examination Study. We identified differentially abundant operational taxonomic units (OTUs) by primary and secondhand tobacco exposure, and used "microbe set enrichment analysis" to assess shifts in microbial oxygen utilization.

RESULTS

Cigarette smoking was associated with depletion of aerobic OTUs (Enrichment Score test statistic ES = -0.75, P = .002) with a minority (29%) of aerobic OTUs enriched in current smokers compared with never smokers. Consistent shifts in the microbiota were observed for current cigarette smokers as for nonsmokers with secondhand exposure as measured by serum cotinine levels. Differential abundance findings were similar in crude and adjusted analyses.

CONCLUSIONS

Results support a plausible link between tobacco exposure and shifts in the oral microbiome at the population level through three lines of evidence: (1) a shift in microbiota oxygen utilization associated with primary tobacco smoke exposure; (2) consistency of abundance fold changes associated with current smoking and shifts along the gradient of secondhand smoke exposure among nonsmokers; and (3) consistency after adjusting for a priori hypothesized confounders.

The Significance of Lactoperoxidase System in Oral Health: Application and Efficacy in Oral Hygiene Products

Lactoperoxidase (LPO) present in saliva are an important element of the nonspecific immune response involved in maintaining oral health. The main role of this enzyme is to oxidize salivary thiocyanate ions (SCN^-) in the presence of hydrogen peroxide (H₂O₂) to products that exhibit antimicrobial activity. LPO derived from bovine milk has found an application in food, cosmetics, and medical industries due to its structural and functional similarity to the human enzyme. Oral hygiene products enriched with the LPO system constitute an alternative to the classic fluoride caries prophylaxis. This review describes the physiological role of human salivary lactoperoxidase and compares the results of clinical trials and in vitro studies of LPO alone and complex dentifrices enriched with bovine LPO. The role of reactivators and inhibitors of LPO is discussed together with the possibility of using nanoparticles to increase the stabilization and activity of this enzyme.

Sources of free radicals and oxidative stress in the oral cavity

OBJECTIVE

An oral cavity is a place especially susceptible to oxidative damage. It is subjected to many environmental pro-oxidative factors or factors that have the ability to generate reactive oxygen species (ROS). The aim of this article is to present the main sources of ROS and oxidative stress in the oral environment.

DESIGN

A literature search was performed using the PubMed and Google Scholar databases.

RESULTS

One of the most important ROS sources in the oral cavity is periodontal inflammation. Other sources of ROS include: xenobiotics (ethanol, cigarette smoke, drugs), food (high-fat diet, high-protein diet, acrolein), dental treatment (ozone, ultrasound, non-thermal plasma, laser light, ultraviolet light), and dental materials (fluorides, dental composites, fixed orthodontic appliances, and titanium fixations). It has been shown that excessive production of ROS in the oral cavity may cause oxidative stress and oxidative damage to cellular DNA, lipids, and proteins, thus predisposing to many oral and systemic diseases.

CONCLUSIONS

Recognition of the exogenous sources of ROS and limitation of exposure to the ROS generating factors can be one of the prophylactic measures preventing oral and systemic diseases. It is suggested that antioxidant supplementation may be helpful in people exposed to excessive production of ROS in the oral cavity system.

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.

Redox Regulation of Inflammatory Processes Is Enzymatically Controlled

Redox regulation depends on the enzymatically controlled production and decay of redox active molecules. NADPH oxidases, superoxide dismutases, nitric oxide synthases, and others produce the redox active molecules superoxide, hydrogen peroxide, nitric oxide, and hydrogen sulfide. These react with target proteins inducing spatiotemporal modifications of cysteine residues within different signaling cascades. Thioredoxin family proteins are key regulators of the redox state of proteins. They regulate the formation and removal of oxidative modifications by specific thiol reduction and oxidation. All of these redox enzymes affect inflammatory processes and the innate and adaptive immune response. Interestingly, this regulation involves different mechanisms in different biological compartments and specialized cell types. The localization and activity of distinct proteins including, for instance, the transcription factor NFκB and the immune mediator HMGB1 are redox-regulated. The transmembrane protein ADAM17 releases proinflammatory mediators, such as TNFα, and is itself regulated by a thiol switch. Moreover, extracellular redox enzymes were shown to modulate the activity and migration behavior of various types of immune cells by acting as cytokines and/or chemokines. Within this review article, we will address the concept of redox signaling and the functions of both redox enzymes and redox active molecules in innate and adaptive immune responses.

Association of salivary peroxidase activity and concentration with periodontal health: A validity study

AIM

Whereas the relationship between myeloperoxidase and periodontitis has been widely examined that between salivary peroxidase and periodontitis has received little attention. We examined how periodontitis depends on both salivary peroxidase activity and concentration.

MATERIALS AND METHODS

A full mouth, clinical assessment of probing depth was performed in a sample of 46 participants aged 25-54 years. To minimise bias, these data were corrected by data from the general population (Study of Health in Pomerania). Using five repeated measurements of activity and concentration over 1 day, we assessed daily biological variability and increased the reliability of salivary peroxidase measurements.

RESULTS

Salivary peroxidase activity was associated with probing depth (interquartile range effect = -0.48; robust estimates of 95% confidence interval: -0.90 to -0.31; p = .0052), and its effect was not confounded by salivary peroxidase concentration. In turn, the effect of salivary peroxidase concentration was confounded by salivary peroxidase activity, and it was smaller than that of activity.

CONCLUSIONS

We found an inverse association between salivary peroxidase activity and probing depth. Thus, our results imply that salivary peroxidase activity could be a protective factor against periodontitis. However, large, well-designed studies are needed to explore the causal mechanisms of this association.

Effects of Tobacco on Salivary Antioxidative and Immunologic Systems

Background: Tobacco use is a harmful habit that causes adverse effects on oral health and plays a most important role in cancer development. Saliva is the first fluid that is exposed to tobacco and its antioxidant system plays an important role in anti-cancer potential; therefore, this study was designed to compare the antioxidant activity and immunologic system of saliva in tobacco users (smokers and smokeless tobacco users) and non-users. Materials and Methods: In this cross-sectional study, unstimulated saliva samples of 75 healthy individuals from three equal groups were investigated. Participants in group A had no periodontal disease and never smoked. Group B had no periodontal disease, never used smokeless tobacco, but had 3 years history of smoking at least 10 cigarettes daily. The twenty-five participants in group C had no periodontal disease and had 1 year history of chewing a 10-g tobacco packet daily. Activity of salivary superoxide dismutase (SOD), salivary glutathione peroxide, and salivary IgA concentration was evaluated. Data were analyzed using SPSS (version 18) and running Kruskal-Wallis test. Statistical significance was set at p<0.05. Results: There were significant differences in the activities of the two enzymes and salivary IgA levels among the three groups. Activity of glutathione peroxide was higher in smokeless tobacco users. (P<0.001) while that of superoxide dismutase was higher in non-tobacco users than users (P<0.001). Salivary IgA levels were higher among smokeless tobacco users (p=0.04). Conclusion: Based on the results of the present study, the use of tobacco products decreases the antioxidative activity of the saliva and increases salivary IgA levels at the same time.

Protein Carbonylation in Human Smokers and Mammalian Models of Exposure to Cigarette Smoke: Focus on Redox Proteomic Studies

SIGNIFICANCE

Oxidative stress is one mechanism whereby tobacco smoking affects human health, as reflected by increased levels of several biomarkers of oxidative stress/damage isolated from tissues and biological fluids of active and passive smokers. Many investigations of cigarette smoke (CS)-induced oxidative stress/damage have been carried out in mammalian animal and cellular models of exposure to CS. Animal models allow the investigation of many parameters that are similar to those measured in human smokers. In vitro cell models may provide new information on molecular and functional differences between cells of smokers and nonsmokers. Recent Advances: Over the past decade or so, a growing number of researches highlighted that CS induces protein carbonylation in different tissues and body fluids of smokers as well as in in vivo and in vitro models of exposure to CS.

CRITICAL ISSUES

We review recent findings on protein carbonylation in smokers and models thereof, focusing on redox proteomic studies. We also discuss the relevance and limitations of these models of exposure to CS and critically assess the congruence between the smoker's condition and laboratory models.

FUTURE DIRECTIONS

The identification of protein targets is crucial for understanding the mechanism(s) by which carbonylated proteins accumulate and potentially affect cellular functions. Recent progress in redox proteomics allows the enrichment, identification, and characterization of specific oxidative protein modifications, including carbonylation. Therefore, redox proteomics can be a powerful tool to gain new insights into the onset and/or progression of CS-related diseases and to develop strategies to prevent and/or treat them. Antioxid. Redox Signal. 26, 406-426.

sIgA, peroxidase and collagenase in saliva of smokers aggressive periodontal patients

BACKGROUND

Tobacco smoking is strongly associated with destructive periodontal disease, alveolar bone loss and poor response to periodontal therapy. The aim of this study was to investigate the effect of smoking on antimicrobials and destructive proteins in the saliva of patients with generalized aggressive periodontal disease.

MATERIAL AND METHODS

The study group consisted of 55 adult subjects. They were classified according to their clinical diagnoses either as having generalized aggressive periodontitis (n = 27; 13 smokers and 14 non-smokers) or as periodontitis-free control group (n = 28; 14 smokers and 14 non-smokers). Total proteins, sIgA, peroxidase and collagenase were quantified in whole saliva. Data were analyzed using one-way ANOVA and Tukey tests.

RESULTS

Statistical differences were found between smokers with periodontal disease and healthy control subjects for sIgA, and between non-smokers with periodontal disease and healthy control subjects for peroxidase. Collagenase activity was higher in smokers and non-smokers with periodontal disease, and tobacco use was found to increase collagenase activity in healthy subjects.

CONCLUSION

Whole saliva from all patients with periodontal disease had higher sIgA and lower peroxidase content. Smokers with periodontitis had higher sIgA than smokers without periodontitis. Smokers with and without periodontitis had higher collagenase activity than non-smokers (with and without periodontitis).

Hydrogen peroxide stimulation of CFTR reveals an Epac-mediated, soluble AC-dependent cAMP amplification pathway common to GPCR signalling

BACKGROUND AND PURPOSE

H2 O2 is widely understood to regulate intracellular signalling. In airway epithelia, H2 O2 stimulates anion secretion primarily by activating an autocrine PGE2 signalling pathway via EP4 and EP1 receptors to initiate cytic fibrosis transmembrane regulator (CFTR)-mediated Cl(-) secretion. This study investigated signalling downstream of the receptors activated by H2 O2 .

EXPERIMENTAL APPROACH

Anion secretion by differentiated bronchial epithelial cells was measured in Ussing chambers during stimulation with H2 O2 , an EP4 receptor agonist or β2 -adrenoceptor agonist in the presence and absence of inhibitors of ACs and downstream effectors. Intracellular calcium ([Ca(2+) ]I ) changes were followed by microscopy using fura-2-loaded cells and PKA activation followed by FRET microscopy.

KEY RESULTS

Transmembrane adenylyl cyclase (tmAC) and soluble AC (sAC) were both necessary for H2 O2 and EP4 receptor-mediated CFTR activation in bronchial epithelia. H2 O2 and EP4 receptor agonist stimulated tmAC to increase exchange protein activated by cAMP (Epac) activity that drives PLC activation to raise [Ca(2+) ]i via Ca(2+) store release (and not entry). Increased [Ca(2+) ]i led to sAC activation and further increases in CFTR activity. Stimulation of sAC did not depend on changes in [HCO3 (-) ]. Ca(2+) -activated apical KCa 1.1 channels and cAMP-activated basolateral KV 7.1 channels contributed to H2 O2 -stimulated anion currents. A similar Epac-mediated pathway was seen following β2 -adrenoceptor or forskolin stimulation.

CONCLUSIONS AND IMPLICATIONS

H2 O2 initiated a complex signalling cascade that used direct stimulation of tmACs by Gαs followed by Epac-mediated Ca(2+) crosstalk to activate sAC. The Epac-mediated Ca(2+) signal constituted a positive feedback loop that amplified CFTR anion secretion following stimulation of tmAC by a variety of stimuli.

Biochemical and pathological studies on peroxidases -an updated review

Peroxidases represent a family of isoenzymes actively involved in oxidizing reactive oxygen species, innate immunity, hormone biosynthesis and pathogenesis of several diseases. Different types of peroxidases have organ, tissues, cellular and sub-cellular level of specificities in their function. Different diseases lead to varied expressions of peroxidases based on several mechanisms proposed. Several researches are going on to understand its deficiency, over-expression and malfunction in relation with different diseases. Some common diseases of mankind like cancer, cardiovascular diseases and diabetes directly or indirectly involve the role of peroxidases. So the status of peroxidase levels may also function as a marker of different diseases. Although many types of diseases in human beings have a strong correlation with tissue specific peroxidases, the clear role of these oxido-reductases is not yet fully understood. Here we are focusing on the role of peroxidases in relations with different diseases occurring due to oxidative stress.

Green tea and vitamin E enhance exercise-induced benefits in body composition, glucose homeostasis, and antioxidant status in elderly men and women

OBJECTIVE

To investigate the effects of green tea plus vitamin E in addition to exercise on body composition and metabolic and antioxidant parameters in healthy elderly individuals.

DESIGN

Interventional randomized controlled prospective trial.

METHODS

For 12 weeks, 22 elderly men and women (age: 71.1 ± 1.2 years; body mass index: 28.3 ± 0.5 kg/m(2) [mean ± SE]) undertook 30 minutes of moderately intense walking 6 d/wk. They were randomly assigned to ingest either green tea plus vitamin E (GTVE; 3 cups and 400 IU, respectively; n = 11) or placebo (n = 11). Data on anthropometrics, fasting insulin and glucose levels, physical fitness, dietary intake, safety parameters, and biomarkers of oxidation status were recorded and analyzed at the start and end of the study.

RESULTS

Though dietary intake was unchanged, improved exercise capacity was followed by a significant reduction in body weight and fasting insulin levels in all participants. Additional consumption of GTVE resulted in a twofold increase in serum vitamin E (from 20.4 to 40.6 μmol/L, p < 0.001) and a decrease of men's and women's waist circumferences (from 100.8 and 95.7 to 96.9 and 85.0 cm, p < 0.05 and p < 0.01, respectively) and fasting glucose levels (from 5.30 to 4.98 mmol/L, p < 0.01). Plasma protein carbonyls dropped (from 0.93 to 0.77 nmol/mg protein, p < 0.05), whereas erythrocyte catalase activities increased (from 26.7 to 29.7 U/g hemoglobin, p < 0.05) in the GTVE group only. Oral peroxidase activities were increased in both groups.

CONCLUSIONS

A daily dose of GTVE in healthy elderly men and women may improve exercise-induced benefits in body composition and glucose tolerance and may also lower oxidative burden.

The salivary β-HEX A% index as an excellent marker of periodontitis in smoking alcohol-dependent persons

Background. Severe periodontitis leading to tooth loss is found in 5–15% of most populations worldwide. Aim. The applicability of salivary β-hexosaminidase (β-HEX A%, percentage of β-HEX A isoenzyme to total β-HEX) and β-HEX B% (β-HEX B/β-HEX) indexes was investigated as a possible marker of periodontitis. Methods. Thirty three alcohol-dependent smokers (AS) and 32 healthy controls (C) were enrolled in the study. The activity of β-HEX was measured spectrophotometrically. Results. β-HEX A% was significantly higher and β-HEX B% was lower in AS than in C group. We found a significant correlation between β-HEX A% and gingival index (GI) and an inverse correlation between β-HEX A% and salivary flow (SF), in all groups. Salivary β-HEX A% index in smoking alcoholics at 0.23 had excellent sensitivity (96%) and specificity (91%); the AUC for β-HEX A% was high (0.937). There were no correlations between amount/duration-time of alcohol drinking/smoking and β-HEX A% or β-HEX B%. We found significant correlations between the time period of denture wearing and GI, papilla bleeding index (PBI), and decayed missing filled teeth index (DMFT) and between GI and the amount of smoked cigarettes per day. Conclusion. Bad periodontal state was most likely due to the nicotine dependence. Salivary β-HEX A% is a promising excellent marker for the diagnosis of periodontitis.

Trefoil factor 3 isolated from human breast milk downregulates cytokines (IL8 and IL6) and promotes human beta defensin (hBD2 and hBD4) expression in intestinal epithelial cells HT-29

Trefoil factors (TFF) are secretory products of mucin producing cells. They play a key role in the maintenance of the surface integrity of oral mucosa and enhance healing of the gastrointestinal mucosa by a process called restitution. TFF comprises the gastric peptides (TFF1), spasmolytic peptide (TFF2), and the intestinal trefoil factor (TFF3). They have an important and necessary role in epithelial restitution within the gastrointestinal tract. Significant amounts of TFF are present in human milk. This study aimed to determine a possible correlation between TFF3 isolated from human breast milk and levels of cytokines (IL8 and IL6) and defensins (hBD2 and hBD4) in intestinal epithelial cells HT-29 treated with trefoil. Samples of human milk were collected within 2-4 weeks postpartum from healthy human mothers (18-30-years-old) by manual breast massage, and TFF3 was purified by ammonium sulfate precipitation, isoelectric precipitation, DEAE-chromatography, and gel filtration. In this work we measured the concentrations and mRNA levels of cytokines and defensins by immunoassay (ELISA) and semiquantitative RT-PCR technique, respectively. Also we measured the peroxidase activity. We present the first evidence of human milk TFF3 purification. Here we show that the presence of TFF3 isolated from milk strongly correlates with downregulation of IL8 and IL6 in human intestinal epithelial cells. On the other hand, TFF3 activated the epithelial cells in culture to produce beta defensins 2 (hBD2) and beta defensins 4 (hBD4). These findings suggest that TFF can activate intestinal epithelial cells and could actively participate in the immune system of breastfed babies by inducing the production of peptides related to innate defence, such as defensins.

Reducing the inhibitory effect of cigarette smoke on the activity of oral peroxidase by the addition of berberine in cigarette filter

This study was carried out to evaluate the effect of cigarette smoke (CS) on the activity of oral peroxidase (OPO) after berberine was added to the cigarette filter. Activated carbon fiber (ACF) was chosen to load berberine as a part of the cellulose acetate (CA) filter to obtain the modified B-ACF cigarette filter. Then the effects of CS from the testing cigarettes on the activity of OPO were investigated in vitro by the 2-nitrobenzoic acid assay, and the smoke chemistry was also analyzed, especially the content of hydrogen cyanide (HCN) in the CS. The results indicated that the loss of activity of OPO in B-ACF filter cigarette group decreased by 20% and 25%, compared with those of ACF and CA filter cigarette groups, respectively. The relative residual activity of OPO in B-ACF filter group was increased with the increase of berberine in the filter compared with the CA filter group. It could be observed that the reduction in HCN might be related to the berberine in the cigarette filter, reducing the inhibition of CS on the activity of OPO.

Salivary enzymes in peptic ulcer disease

AIM

Peptic ulcer, the common disease of the upper gastro-intestinal tract, occurs in about 5-10% of the world's population. Therefore, diagnosis of trace disease progression with a noninvasive method is of prime importance in the field of healthcare research. The aim of this study was to evaluate the validity of salivary enzymes as noninvasive biomarkers for peptic ulcer.

MATERIALS AND METHODS

In practice, 34 peptic ulcer patients and 30 healthy subjects donated their un-stimulated saliva samples after 8 h of fasting. The activity of some selected enzymes was measured using appropriate enzymatic assay methods.

RESULTS

The results indicated an overall alternation in enzymatic activity of saliva in patients suffering from peptic ulcer. Biological activity of a-amylase, peroxidase and lactate dehydrogenase, showed significantly higher values in almost all patients as compared to control subjects.

CONCLUSIONS

Based on the results of salivary enzyme activity, it was concluded that besides the influence of their peptic ulcer on enzyme activity of saliva, the considerably higher activity of a-amylase could also be related to the major role of the enzyme on physiological oxidative stress.

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.

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.

Proteomic analysis of whole human saliva detects enhanced expression of interleukin-1 receptor antagonist, thioredoxin and lipocalin-1 in cigarette smokers compared to non-smokers

A gel-based proteomics approach was used to screen for proteins of differential abundance between the saliva of smokers and those who had never smoked. Subjecting precipitated proteins from whole human saliva of healthy non-smokers to two-dimensional electrophoresis (2-DE) generated typical profiles comprising more than 50 proteins. While 35 of the proteins were previously established by other researchers, an additional 22 proteins were detected in the 2-DE saliva protein profiles generated in the present study. When the 2-DE profiles were compared to those obtained from subjects considered to be heavy cigarette smokers, three saliva proteins, including interleukin-1 receptor antagonist, thioredoxin and lipocalin-1, showed significant enhanced expression. The distribution patterns of lipocalin-1 isoforms were also different between cigarette smokers and non-smokers. The three saliva proteins have good potential to be used as biomarkers for the adverse effects of smoking and the risk for inflammatory and chronic diseases that are associated with it.

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.

A metaproteomic analysis of the human salivary microbiota by three-dimensional peptide fractionation and tandem mass spectrometry

Metagenomics uses gene expression patterns to understand the taxonomy and metabolic activities of microbial communities. Metaproteomics applies the same approach to community proteomes. Previously, we used a novel three-dimensional peptide separation method to identify over 2000 salivary proteins. This study used those data to carry out the first metaproteomic analysis of the human salivary microbiota. The metagenomic software MEGAN generated a phylogenetic tree, which was checked against the Human Oral Microbiome Database (HOMD). Pathway analyses were performed with the Clusters of Orthologous Groups and MetaCyc databases. Thirty-seven per cent of the peptides were identifiable only at the level of cellular organisms or bacteria. The rest were distributed among five bacterial phyla (61%), archea (0.5%), and viruses (0.8%); 29% were assignable at the genus level, and most belonged to Streptococcus (17%). Eleven per cent of all peptides could be assigned to species. Most taxa were represented in HOMD and they included well-known species such as periodontal pathogens. However, there also were 'exotic' species including aphid endosymbionts; plant, water, and soil bacteria; extremophiles; and archea. The pathway analysis indicated that peptides were linked to translation (37%), followed by glycolysis (19%), amino acid metabolism (8%), and energy production (8%). The taxonomic structure of the salivary metaproteome is very diverse but is dominated by streptococci. 'Exotic' species may actually represent close relatives that have not yet been sequenced. Salivary microbes appear to be actively engaged in protein synthesis, and the pathway analysis is consistent with the metabolism of salivary glycoproteins.

Oral cancer, cigarette smoke and mitochondrial 18kDa translocator protein (TSPO) - In vitro, in vivo, salivary analysis

Oral cancer features high rates of mortality and morbidity, and is in dire need for new approaches. In the present study we analyzed 18 kDa translocator protein (TSPO) expression in oral (tongue) cancer tumors by immunohistochemistry. We also assayed TSPO binding in human tongue cancer cell lines and in the cellular fraction of saliva from tongue cancer patients, heavy cigarette smokers, and non-smoking healthy people as controls. Concurrently, TSPO protein levels, cell viability, mitochondrial membrane potential (Deltapsi(m)), and general protein levels were analyzed. TSPO expression could be significantly enhanced in oral cancer tumors, compared to unaffected adjacent tissue. We also found that five-year survival probability dropped from 65% in patients with TSPO negative tumors to 7% in patients with highly expressed TSPO (p<0.001). TSPO binding capacity was also pronounced in the human oral cancer cell lines SCC-25 and SCC-15 (3133+/-643 fmol/mg protein and 6956+/-549 fmol/mg protein, respectively). Binding decreased by 56% and 72%, in the SCC-25 and SCC-15 cell lines, respectively (p<0.05) following CS exposure in cell culture. In the cellular fraction of saliva of heavy smokers TSPO binding was lower than in non-smokers (by 53%, p<0.05). Also the cellular fraction of saliva exposed to CS in vitro showed decreased TSPO binding compared to unexposed saliva (by 30%, p<0.001). Interestingly, oral cancer patients also displayed significantly lower TSPO binding in the cellular fraction of saliva compared to healthy controls (by 40%, p<0.01). Our results suggest that low TSPO binding found in the cellular fraction of saliva may depend on genetic background as well as result from exposure to CS. We suggest that this may be related to a predisposition for occurrence of oral cancer.

Myeloperoxidase interaction with peroxynitrite: chloride deficiency and heme depletion

Myeloperoxidase (MPO) is a hemoprotein involved in the leukocyte-mediated defense mechanism and uses hydrogen peroxide (H2O2) and chloride (Cl(-)) to produce hypochlorous acid. In human saliva and in hypochloremic alkalosis syndrome occurring in breast-fed infants, the MPO-H2O2 system functions in a lower Cl(-) concentration (10-70 mM) compared to plasma levels (100 mM) as part of the antibacterial defense system. The impact of low Cl(-) concentration and exposure to high peroxynitrite (ONOO(-)) synthesized from cigarette smoke or oxidative stress on MPO function is still unexplored. Rapid mixing of ONOO(-) and MPO caused immediate formation of a transient intermediate MPO Compound II, which then decayed to MPO-Fe(III). Double mixing of MPO with ONOO(-) followed by H2O2 caused immediate formation of Compound II, followed by MPO heme depletion, a process that occurred independent of ONOO(-) concentration. Peroxynitrite/H2O2-mediated MPO heme depletion was confirmed by HPLC analysis, and in-gel heme staining showing 60-70% less heme content compared to the control. A nonreducing denaturing SDS-PAGE showed no fragmentation or degradation of protein. Myeloperoxidase heme loss was completely prevented by preincubation of MPO with saturating amounts of Cl(-). Chloride binding to the active site of MPO constrains ONOO(-) binding by filling the space directly above the heme moiety or by causing a protein conformational change that constricts the distal heme pocket, thus preventing ONOO(-) from binding to MPO heme iron. Peroxynitrite interaction with MPO may serve as a novel mechanism for modulating MPO catalytic activity, influencing the regulation of local inflammatory and infectious events in vivo.

Salivary DNA, lipid, and protein oxidation in nonsmokers with periodontal disease

Reactive oxygen species (ROS) are implicated in the destruction of the periodontium during periodontitis. The imbalance in oxidant activity may be a key factor. The aim of this paper is to determine whether periodontitis is associated with increased oxidative damage to DNA, lipids, and proteins and modification of total antioxidant capacity (TAC) in saliva. Saliva was collected from 58 periodontitis patients and 234 healthy controls, all nonsmokers. Periodontal disease status was characterized using the Community Periodontal Index of Treatment Needs (CPITN). Assays for 8-OHdG (ELISA), 8-epi-PGF2alpha (ELISA), and total protein carbonyls (ELISA), and oxy-blotting (Western)/mass spectrometry were performed to quantify oxidative damage to nucleic acids, lipids, total and individual proteins, respectively, in whole nonstimulated saliva. Salivary TAC was measured by inhibition of ABTS oxidation by metmyoglobin. We observed (i) significantly higher levels of 8-OHdG, 8-epi-PGF2alpha, and carbonylated proteins in saliva of periodontal patients as compared with controls (P=0.0003, <0.0001 and <0.0001); (ii) 8-OHdG, 8-epi-PGF2alpha, and carbonylated proteins were independently negatively associated with CPITN (P=0.004, 0.02, and <0.0001); (iii) a positive correlation between salivary TAC and periodontal disease status in the study group (P<0.0001); and (iv) specific oxidation of transferrin, human IgG1 heavy chain fragment, and salivary amylase in periodontitis. Periodontal disease is associated with increased oxidative modification of salivary DNA, lipids, and proteins. Augmented salivary total antioxidant capacity may represent an adaptive response to oxidative stress. Salivary amylase, transferrin, and human IgG1 heavy chain fragments are particularly prone to enhanced oxidation in periodontitis.

Serum and salivary oxidative analysis in Complex Regional Pain Syndrome

Although both inflammatory and neural mechanisms have been suggested as potential contributors to Complex Regional Pain Syndrome type I (CRPS-I), the pathogenesis of the syndrome is still unclear. Clinical trials have shown that free radical scavengers can reduce signs and symptoms of CRPS-I, indirectly suggesting that free radicals and increased oxidative stress are involved in the pathogenesis of CRPS-I. This study investigated this premise by determining the levels of antioxidants in the serum and saliva of 31 patients with CRPS-I and in a control group of 21 healthy volunteers. Serum lipid peroxidation products (MDA) and all antioxidative parameters analyzed were significantly elevated in CRPS-I patients: median salivary peroxidase and superoxide dismutase (SOD) activity values, uric acid (UA) concentration and total antioxidant status (TAS) values were higher in CRPS-I patients by 150% (p=0.01), 280% (p=0.04), 60% (p=0.0001), and 200% (p=0.0003), respectively, as compared with controls. Similar although not as extensive pattern of oxidative changes were found in the serum: mean serum UA and MDA concentrations and TAS value in the CRPS-I patients were higher by 16% (p=0.04), 25% (p=0.02), and 22% (p=0.05), respectively, than in the controls. Additionally, median salivary albumin concentration and median salivary LDH activities in the patients were 2.5 times (p=0.001) and 3.1 (p=0.004) times higher than in the controls. The accumulated data show that free radicals are involved in the pathophysiology of CRPS-I, which is reflected both in serum and salivary analyses. These data could be used for both diagnostic and therapeutic purposes in CRPS-I patients.

Compositional and oxidative analysis in the saliva and serum of predialysis chronic kidney disease patients and end-stage renal failure patients on peritoneal dialysis

Chronic renal failure (CRF) is often treated with peritoneal dialysis, although increased oxidative stress has been reported in such patients. The purpose of the current study was to analyze and compare oxidative stress and other compositional parameters in the saliva, serum and peritoneal dialytic fluid (PDF) of patients with chronic kidney disease (CKD), including predialysis CKD patients and end-stage renal disease (ESRD) patients treated with peritoneal dialysis. Twenty-three consenting patients participated in the current study. Saliva and serum samples collected from both groups and PDF from the dialysis patients were all examined for uric acid (UA), total antioxidant status, total protein and total albumin. The antioxidant enzyme peroxidase was examined both in saliva and serum, while the antioxidant enzyme superoxide dismutase (SOD) was examined solely in saliva. Various electrolytes were examined. Discrepancies were found between saliva and serum antioxidant status following peritoneal dialysis in ESRD patients. Oxidative stress was enhanced in the saliva but reduced in the serum. Significant changes in both oxidative-related and non-related parameters were demonstrated in saliva, serum and PDF. Salivary lactate dehydrogenase was substantially lower in the dialysis patients (by 92%, P = 0.02), as was the salivary UA concentration (by 22%, P = 0.05) and serum UA concentration (by 20%, P = 0.03). In contrast, salivary peroxidase and SOD were higher by 15% and 35%, respectively (P = 0.01), in these patients. We suggest monitoring salivary UA for assessing the baseline oral oxidative status of CRF and dialyzed patients.

Protein carbonyl levels in serum and gingival crevicular fluid in patients with chronic periodontitis

OBJECTIVE

Evidence reveals the role of reactive oxygen species (ROS) in many pathologies including periodontitis. Protein carbonylation is the most widely used biomarker for oxidative damage to proteins, and reflects cellular damage induced by ROS. In this study protein carbonyl (PC) levels in serum and gingival crevicular fluid (GCF) in patients with chronic periodontitis (CP) was evaluated.

MATERIALS AND METHODS

Thirty-three patients with CP and 24 healthy controls were included in the study. Following the clinical measurements and samplings, total protein levels in serum and GCF were determined by Bradford method, and serum and GCF PC levels were measured by modified Levine method.

RESULTS

PC levels in serum and GCF were significantly higher in the CP group compared to the control group (p<0.05). In all subjects, serum and GCF PC levels showed statistically significant positive correlations with all clinical parameters (p<0.05).

CONCLUSIONS

The results suggest that both systemic and local/periodontal protein carbonylation increase in CP compared to health and that elevated levels of PCs may be a sign of oxidative damage in periodontitis and correlate well with the periodontal status.

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.

Salivary and gustatory alterations among bulimia nervosa patients

OBJECTIVE AND DESIGN

This study systematically examined salivary composition and taste perception and monitored related subjective complaints in a group of bulimia nervosa (BN) patients.

SUBJECTS

Fifty-two consenting female individuals participated in the current cross-sectional study, 26 patients diagnosed with BN according to the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria (mean age: 24+/-7 years) and 26 healthy controls matching in age and body mass index (BMI).

METHODS

All participants were given diagnostic BN-related questionnaires, had taste and salivary-composition analyses and were monitored for oral sensorial complaints. The patients were also subjected to psychological and psychiatric examinations focusing on established criteria known to be pathognomonic of the disease (including binge eating episodes, depression, impulsive traits, enhanced awareness of body image, typical compensatory behavior, and so on).

RESULTS

The self-answered questionnaires of Bulimic Investigatory Test Edinburgh (BITE), Beck Depression Inventory (BDI), brief symptom inventory (BSI) and impulsivity scale (IS) revealed highly significant differences between the two groups with respect to the various BN diagnostic symptoms of the patients (P=0.0001). Subjective and objective examinations showed an overall disturbed salivary and taste profile in BN patients, who complained of xerostomia (dry mouth) and taste aberration or oral burning sensation.

CONCLUSIONS

Regardless of the specific mechanism responsible for the disturbed salivary and taste profile in BN patients, these observed changes are associated with active illness. Accordingly, administration of therapeutic agents, including antioxidants, anti-inflammatory drugs and saliva substitutes, to the oral cavity (and maybe even systemically) of BN patients should be considered.

Oxidative stress in lymphocytes, neutrophils, and serum of oral cavity cancer patients: modulatory array of L-glutamine

OBJECTIVES

Our aim was to assess the oxidative stress and ameliorative effect of L-glutamine in serum, neutrophils, and lymphocytes of oral cancer patients by measuring the levels of malondialdehyde (MDA) and antioxidants.

MATERIALS AND METHODS

This study has been conducted on serum and specific blood cells in adult, male oral cancer patients (stage III-6, stage IV-42) and normal subjects of an equal number of age and sex-matched disease-free healthy subjects. The levels of lipid peroxidation and antioxidant enzymes were assayed using spectrophotometric methods.

RESULTS

MDA levels were elevated, and antioxidant enzyme status was decreased significantly in all groups of cancer patients simultaneously, but after supplementation of "glutammune" (66.66% L-glutamine), oxidative stress has been alleviated to some extent; especially, it has repaired the glutathione cascade system.

CONCLUSION

We conclude that oxidative stress is due to the enhanced lipid peroxidation and decrease in antioxidant enzymes, and it can be restored with dietary supplementation of L-glutamine related drug.

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.

Characterization of the antioxidant profile of human saliva in peri-implant health and disease

OBJECTIVES

Peri-implant disease is considered to be an inflammatory disease, but many aspects of its pathogenesis remain unknown. At present, peri-implant disease is considered to be initiated and perpetuated by a small group of predominantly Gram-negative, anaerobic, or micro-aerophilic bacteria that colonize the subgingival area. Bacteria cause the observed tissue destruction directly by toxic products and indirectly by activating host defence systems, i.e. inflammation. A variety of molecular species appears in the inflamed tissues, among them are reactive species such as free radicals and reactive oxygen species (ROS). The purpose of this study was to assess levels of various antioxidants in saliva to identify differences between the saliva of patients with healthy peri-implant tissues and patients with peri-implant disease, and to examine whether the whole saliva of those with peri-implant disease conditions might have lower levels of antioxidants than that of healthy individuals.

MATERIALS AND METHODS

Thirty healthy adult volunteers (14 men and 16 women) with implant-supported overdentures (Ankylos Biofunctional Implants) were selected from the group of patients from Tallinn Dental Clinic. Biochemical and clinical parameters evaluated were the following ones: the levels of urate, ascorbate, myeloperoxidase in saliva, total antioxidant status of saliva, pocket probing depth (mm), gingival index (0, 1, 2, or 3), and bleeding on probing (0 or 1).

RESULTS AND CONCLUSION

Total antioxidant status (TAS) of saliva and concentration of uric acid and ascorbate, which are the main salivary antioxidants, are significantly decreased in patients with peri-implant disease. TAS in healthy subjects was 0.41+/-0.10 for resting saliva and 0.31+/-0.09 for stimulated saliva; in diseased subjects TAS was 0.19+/-0.07 and 0.12+/-0.03, respectively. In healthy subjects, the concentration of urate was 307.2+/-78.06 microM/l in resting saliva and 241.5+/-89.09 microM/l in stimulated saliva. In diseased patients, the concentration of urate was 120+/-36.13 and 91.60+/-39.35 microM/l, respectively. The concentration of ascorbate did not differ in resting and stimulated saliva. In healthy subjects, it was 2.79+/-0.81 mg/l and in diseased subjects, it was 1.54+/-0.30 mg/l. This may indicate that excessive ROS production in peri-implant disease is leading to the situation of excessive oxidative stress, which may be an important factor contributing the destruction of peri-implant tissues. The importance of these findings may be the better understanding of the processes involved in the pathogenesis of peri-implant disease and that the treatment of peri-implant disease may involve adjuvant anti-oxidants supplementation together with cumulative interceptive supportive therapy concept introduced by Mombelli & Lang.

Does cotinine act upon reactive oxygen species and peroxidases?

Nicotine, an oxidizing agent, is certainly one of the most widely used alkaloids in the world. It is, together with its main metabolite, cotinine, responsible for tobacco-dependence. The use of tobacco is closely associated with lung disease, morphological leukocyte modification and generation of oxidant species. The aim of this study was to look for a possible relationship between cotinine, oxidant species generation and oxidative processes. After studying the action of cotinine in some chemical oxidation models and on the enzymatic kinetics of peroxidases (myeloperoxidase and horseradish peroxidase), we concluded that cotinine does not act directly upon H2O2, HOCl, taurine chloramines, horseradish peroxidase or myeloperoxidase.

COMPARISON OF PEROXIDASE RESPONSE TO MENTAL ARITHMETIC STRESS IN SALIVA OF SMOKERS AND NON-SMOKERS

Saliva is the first body fluid to encounter exogenous materials or gases such as cigarette smoke (CS). The aim of this study was to examine whether smoking affects oral peroxidase (OPO) reactivity to mental stress. The subjects were 39 non-smokers and 10 smokers. In the experiment, the Kraepelin psychodiagnostic test as a psychological stressor and saliva was sampled 30 min before, just before, immediately after, and 30 min after the beginning of the test. OPO reactivity to the test between smokers and non-smokers was measured in addition to uric acid concentration, flow rate, IgA, thiocyanate (SCN-) concentration, amylase activity as a salivary stress marker, and ultra-weak chemiluminescence (UCL) level, which is indicative of salivary antioxidative and antibacterial abilities. Moreover, we studied the effect of smoking on the response of salivary peroxidase (SPO) and myeloperoxidase (MPO) activity to mental stress, respectively. The results showed that the IgA concentration, amylase activity, SCN(- concentration, and UCL level are higher in the non-smoking group than smoking group and the IgA concentration and UCL level increased in the non-smokers significantly just after the Kraepelin test. The levels of SCN-) were higher in smokers than in non-smokers and OPO activity was greater in the non-smoking group in all sessions. Furthermore, only the non-smokers had significantly increased MPO activity just after the test. MPO may play a crucial role in the response to acute psychological stress besides inflammation, and CS suppresses this response significantly.