Salivary 8-hydroxy-2-deoxyguanosine, malondialdehyde, vitamin C, and vitamin E in oral pre-cancer and cancer: diagnostic value and free radical mechanism of action

Alteration of salivary LPO, MDA, LDH, glutathione, GPx, SOD and vitamins in oral submucous fibrosis: A three-level meta-analysis study

This study aims to investigate the alteration of salivary biomarker profiling in the development of oral submucous fibrosis (OSMF) and to explore the influence of saliva in the diagnosis of OSMF. A systematic search of published articles using the PRISMA guidelines was conducted to identify relevant studies on OSMF and saliva. All eligible studies, including case-control, cross-sectional studies, cohort, and pilot studies, contained the evaluation of salivary biomarker profiling in patients with OSMF. Salivary biomarker data from 28 selected articles were categorized into nine groups, and their mean values were determined. A three-step meta-analysis was performed by grouping salivary biomarker profiling into more heterogeneous categories based on OSMF classification, considering functional, histological, and clinical grading. The salivary biomarker profiling analysis revealed significant alterations in all markers, indicating their efficacy in OSMF diagnosis. Subgroup analyses highlighted significant associations in oxidative stress and protein with increased mean values, particularly emphasizing lipid peroxidase (LPO), malondialdehyde (MDA), and lactate dehydrogenase (LDH). Conversely, decreased mean values were observed in glutathione, glutathione peroxidase (GPx), superoxide dismutase (SOD), and vitamins. Notably, OSMF grading analysis demonstrated a significant difference in weighted effect sizes for histological grading, particularly in stage IV. The study underscores the alteration of specific salivary biomarkers, particularly those associated with LPO, MDA, LDH, glutathione, GPx, SOD, and vitamins, in diagnosing and grading OSMF.

Salivary oxidative stress biomarkers in periodontitis-free smokers: a cross sectional study

BACKGROUND

Salivary oxidative stress has been extensively studied with attempts to correlate changes in the oxidative stress markers with local and systemic factors, including smoking. The objective of this study was to evaluate the influence of two forms of smoking, cigarettes and waterpipe smoking (WPS), on selected oxidative stress biomarkers in saliva.

METHODS

Three groups of participants were enrolled into the study, controls (never smokers), cigarette smokers and WPS. Participants were clinically free from periodontitis and systemic conditions known to affect the saliva constituents. Unstimulated whole saliva samples were collected according to a standard protocol and concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG), myeloperoxidase (MPO), malondialdehyde (MDA), total antioxidant capacity (TAC), and cortisol. The one-way ANOVA test was used to compare the levels of each oxidative stress biomarker between the three study groups and the hierarchical linear regression analysis was used to test the levels of salivary cortisol for prediction of other oxidative stress biomarkers. Significance levels were set at 95% confidence intervals and probability values ≤0.05.

RESULTS

8-OHdG was highest in WPS group (mean±SE 11,030.35±1829.16 pg/mL) while MDA and cortisol levels were highest in the cigarette smokers group (mean±SE 3.33±0.52 µM and 3.99±0.48 ng/mL, respectively) and MPO was highest in the control group (mean±SE 7.760±1.55 ng/mL). WPS group showed the highest TAC (mean±SE 0.3±0.03 mM). However, none of the tested makers reached a statistically significant difference.

CONCLUSIONS

Despite subtle changes in some biomarkers, the salivary oxidative stress does not appear to be significantly influenced by smoking habits in periodontitis-free smokers.

Mechanisms and markers of malignant transformation of oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic premalignant disease associated with betel quid chewing. Epidemiological studies indicate that there are approximately 5 million individuals suffering from OSF worldwide, with a concerning malignancy transformation rate of up to 4.2 %. When OSF progresses to oral squamous cell carcinoma (OSCC), the 5-year survival rate for OSCC drops to below 60 %. Therefore, early screening and diagnosis are essential for both preventing and effectively treating OSF and its potential malignant transformation. Numerous studies have shown that the malignant transformation of OSF is associated with various factors, including epigenetic reprogramming, epithelial-mesenchymal transition, hypoxia, cell cycle changes, immune regulation disturbances, and oxidative damage. This review article focuses on the unraveling the potential mechanisms underlying the malignant transformation of OSF, as well as the abnormal expression of biomarkers throughout this transformative process, with the aim of aiding early screening for carcinogenic changes in OSF. Furthermore, we discuss the significance of utilizing blood and saliva components from patients with OSF, along with optical diagnostic techniques, in the early screening of OSF malignant transformation.

New insights into redox-related risk factors and therapeutic targets in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common cancer in the oral cavity accounting for 90 % of oral cancer with a global incidence of 350.000 new cases per year. Curative resection along with adjuvant radiation therapy or a combination of radiotherapy with chemotherapy remain as gold standard in treating OSCC. Still, local recurrence, lymph nodal recurrence, and complications of radiation remain the main cause of tumor-related mortality. Reactive oxygen species are not only correlated to the etiology of OSCC due to oxidative DNA damage, lipid peroxidation or effecting signal transduction cascades that effect cell proliferation and tumorigenesis, but are also of great interest in the therapy of OSCC patients. As induced oxidative stress can be used therapeutically for the induction of tumor cell death, redox targets might be a therapeutic addition to the conventional treatment options. In this review, we discuss markers of impaired redox homeostasis as well as potential redox-related treatment targets in OSCC.

Exploring Possible Diagnostic Precancerous Biomarkers for Oral Submucous Fibrosis: A Narrative Review

Oral submucous fibrosis (OSF) stands as a progressive oral ailment, designated as a potentially malignant disorder. OSF has gained widespread recognition as a significant precursor to malignant transformation. In the pursuit of dependable, straightforward, and non-invasive diagnostic measures for the early detection of oral malignant progression, research has delved into potential diagnostic biomarkers of OSF. This comprehensive review delves into current investigations that explore the correlation between various biomarkers and OSF. The molecular biomarkers of OSF are categorized based on cytology and sampling methods. Moreover, this review encompasses pertinent studies detailing how these biomarkers are acquired and processed. Within this scope, we scrutinize four potential biomarkers that hold the promise of facilitating the development of diagnostic tools for detecting early-stage OSF.

Saliva - a new opportunity for fluid biopsy

Saliva is a complex biological fluid with a variety of biomolecules, such as DNA, RNA, proteins, metabolites and microbiota, which can be used for the screening and diagnosis of many diseases. In addition, saliva has the characteristics of simple collection, non-invasive and convenient storage, which gives it the potential to replace blood as a new main body of fluid biopsy, and it is an excellent biological diagnostic fluid. This review integrates recent studies and summarizes the research contents of salivaomics and the research progress of saliva in early diagnosis of oral and systemic diseases. This review aims to explore the value and prospect of saliva diagnosis in clinical application.

Abnormal expression of HADH, an enzyme of fatty acid oxidation, affects tumor development and prognosis (Review)

Tumor occurrence and progression are closely associated with abnormal energy metabolism and energy metabolism associated with glucose, proteins and lipids. The reprogramming of energy metabolism is one of the hallmarks of cancer. As a form of energy metabolism, fatty acid metabolism includes fatty acid uptake, de novo synthesis and β‑oxidation. In recent years, the role of abnormal fatty acid β‑oxidation in tumors has gradually been recognized. Mitochondrial trifunctional protein (MTP) serves an important role in fatty acid β‑oxidation and HADH (two subtypes: α subunit, HADHA and β subunit, HADHB) are important subunits of MTP. HADH participates in the steps of 2, 3 and 4 fatty acid β‑oxidation. However, there is no review summarizing the specific role of HADH in tumors. Therefore, the present study focused on HADH as the main indicator to explore the changes in fatty acid β‑oxidation in several types of tumors. The present review summarized the changes in HADH in 11 organs (cerebrum, oral cavity, esophagus, liver, pancreas, stomach, colorectum, lymph, lung, breast, kidney), the effect of up‑ and downregulation and the relationship of HADH with prognosis. In summary, HADH can be either a suppressor or a promoter depending on where the tumor is located, which is closely associated with prognostic assessment. HADHA and HADHB have similar prognostic roles in known and comparable tumors.

Oxidatively Damaged Nucleic Acid: Linking Diabetes and Cancer

Significance: Our current knowledge of the mechanism between diabetes and cancer is limited. Oxidatively damaged nucleic acid is considered a critical factor to explore the connections between these two diseases. Recent Advances: The link between diabetes mellitus and cancer has attracted increasing attention in recent years. Emerging evidence supports that oxidatively damaged nucleic acid caused by an imbalance between reactive oxygen species generation and elimination is a bridge connecting diabetes and cancer. 8-Oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydroguanosine assume important roles as biomarkers in assessing the relationship between oxidatively damaged nucleic acid and cancer. Critical Issues: The consequences of diabetes are extensive and may lead to the occurrence of cancer by influencing a combination of factors. At present, there is no direct evidence that diabetes causes cancer by affecting a single factor. Furthermore, the difficulty in controlling variables and differences in detection methods lead to poor reliability and repeatability of results, and there are no clear cutoff values for biomarkers to indicate cancer risk. Future Directions: A better understanding of connections as well as mechanisms between diabetes and cancer is still needed. Both diabetes and cancer are currently intractable diseases. Further exploration of the specific mechanism of oxidatively damaged nucleic acid in the connection between diabetes and cancer is urgently needed. In the future, it is necessary to further take oxidatively damaged nucleic acid as an entry point to provide new ideas for the diagnosis and treatment of diabetes and cancer. Experimental drugs targeting the repair process of oxidatively generated damage require an extensive preclinical evaluation and could ultimately provide new treatment strategies for these diseases. Antioxid. Redox Signal. 37, 1153-1167.

Dietary and Antioxidant Vitamins Limit the DNA Damage Mediated by Oxidative Stress in the Mother-Newborn Binomial

During pregnancy, appropriate nutritional support is necessary for the development of the foetus. Maternal nutrition might protect the foetus from toxic agents such as free radicals due to its antioxidant content. In this study, 90 mothers and their children were recruited. DNA damage mediated by oxidative stress (OS) was determined by the levels of 8-hidroxy-2′-deoxyguanosine (8-OHdG) in the plasma of women and umbilical cord blood. The mothers and newborns were categorised into tertiles according to their 8-OHdG levels for further comparison. No relevant clinical differences were observed in each group. A strong correlation was observed in the mother−newborn binomial for 8-OHdG levels (Rho = 0.694, p < 0.001). In the binomial, a lower level of 8-OHdG was associated with higher consumption of calories, carbohydrates, lipids, and vitamin A (p < 0.05). In addition, the levels of 8-OHdG were only significantly lower in newborns from mothers with a higher consumption of vitamin A and E (p < 0.01). These findings were confirmed by a significant negative correlation between the 8-OHdG levels of newborns and the maternal consumption of vitamins A and E, but not C (Rho = −0.445 (p < 0.001), −0.281 (p = 0.007), and −0.120 (p = 0.257), respectively). Multiple regression analysis showed that the 8-OHdG levels in mothers and newborns inversely correlated with vitamin A (β = −1.26 (p = 0.016) and −2.17 (p < 0.001), respectively) and pregestational body mass index (β = −1.04 (p = 0.007) and −0.977 (p = 0.008), respectively). In conclusion, maternal consumption of vitamins A and E, but not C, might protect newborns from DNA damage mediated by OS.

Oxidation, Glycation, and Carbamylation of Salivary Biomolecules in Healthy Children, Adults, and the Elderly: Can Saliva Be Used in the Assessment of Aging?

Background

Aging is inextricably linked to oxidative stress, inflammation, and posttranslational protein modifications. However, no studies evaluate oxidation, glycation, and carbamylation of salivary biomolecules as biomarkers of aging. Saliva collection is non-invasive, painless, and inexpensive, which are advantages over other biofluids.

Methods

The study enrolled 180 healthy subjects divided into six groups according to age: 6–13, 14–19, 20–39, 40–59, 60–79, and 80–100 years. The number of individuals was determined a priori based on our previous experiment (power of the test = 0.8; α = 0.05). Non-stimulated saliva and plasma were collected from participants, in which biomarkers of aging were determined by colorimetric, fluorometric, and ELISA methods.

Results

The study have demonstrated that modifications of salivary proteins increase with age, as manifested by decreased total thiol levels and increased carbonyl groups, glycation (Nε-(carboxymethyl) lysine, advanced glycation end products (AGE)) and carbamylation (carbamyl-lysine) protein products in the saliva of old individuals. Oxidative modifications of lipids (4-hydroxynonenal) and nucleic acids (8-hydroxy-2’-deoxyguanosine (8-OHdG)) also increase with age. Salivary redox biomarkers correlate poorly with their plasma levels; however, salivary AGE and 8-OHdG generally reflect their blood concentrations. In the multivariate regression model, they are a predictor of aging and, in the receiver operating characteristic (ROC) analysis, significantly differentiate children and adolescents (under 15 years old) from the working-age population (15–64 years) and the older people (65 years and older).

Conclusion

Salivary AGE and 8-OHdG have the most excellent diagnostic utility in assessing the aging process. Saliva can be used to evaluate the aging of the body.

Recognizing the salivary panomics for the clinical application in oral potentially malignant disorders

Oral cancer arises as a result of multistep carcinogenic progress from precursor lesion to oral squamous cell carcinoma through collective mutational process occur in the stem cells of mucosal epithelium. The detection of such oral potentially malignant disorders (OPMDs)/cancer in subclinical level will greatly improve the prognosis of a patient. The highly specific and sensitive salivary biomarkers have functioned in detection, prediction, surveillance and therapeutic monitoring of the diseases of interest. The aim of the review is to appraise various salivary biomarkers for the clinical utility in OPMDs. An electronic web-supported search was performed via PubMed, ScienceDirect and Google Scholar search engine since the year 2015–2019. A total of 28 research articles were selected for the review after screening and assessment. The various genomic, transcriptomic, proteomic, metabolomic and miscellaneous markers were analyzed and their characteristics and clinical application in OPMD patients were discussed. miR-21, miR-31, miR-84, H3F3A mRNA + IL-8P, matrix metalloproteinase-9, chemerin, tumor necrosis factor-alpha, cytokeratin-10, ornithine + O-hydroxybenzoate + R5F, 8-hydroxy-2-deoxyguanosine, malondialdehyde, Vitamin E and Vitamin C are identified as potential markers for OPMD patients. Scientifically validated, reliable and economical clinical biomarkers in OPMDs would serve as evidence-based treatment from patient point of view. Further longitudinal studies are needed to verify the accuracy and validate the applicability of these diagnostic/prognostic markers. Saliva has been reported as a valuable noninvasive valuable tool in biomarker identification. Recent advancements in salivary biomarker identification techniques lead to various potential biomarkers with precise outcome. The utilization of these biomarkers for the clinical application in OPMDs depends on the feasibility and personal choice of the clinician.

Systematic Review and Meta-Analysis of Oxidative Stress and Antioxidant Markers in Oral Lichen Planus

Background

Oral lichen planus (OLP) is a relatively common chronic inflammatory disease of unknown etiology, which might be caused by oxidative stress and impaired antioxidant defense.

Objective

To systematically investigate the markers of oxidative stress and antioxidant systems in the saliva and blood from OLP patients and healthy controls.

Methods

The PubMed, Cochrane Library, and Embase were systematically queried to collect data from studies in which oxidative stress/antioxidant markers from OLP and healthy subjects had been evaluated until March 10, 2021.

Results

A total of 28 studies fulfilled inclusion criteria, and 25 of them, having 849 OLP patients and 1,052 control subjects and analyzing 12 oxidative stress and antioxidant state marker levels, were subjected to meta-analysis. We found a significant decrease in total antioxidant capacity (TAC) and uric acid (UA) and a significant increase in malondialdehyde (MDA) and nitric oxide (NO) levels in the saliva and serum/plasma of OLP patients. Moreover, a significant elevation of 8-hydroxy-deoxyguanosine (8-OHdG) and advanced oxidation protein product (AOOP) level and a decrease in vitamin C were also observed in the saliva of the OLP group. In contrast, salivary vitamin A, zinc, glutathione peroxidase (GPx), vitamin E, and nitrite were not significantly different between the two groups. In single studies, markers of oxidative stresses such as superoxide dismutase (SOD) and 8-isoprostanelevels were elevated in OLP, and antioxidant parameters such as glutathione (GSH) and total protein (TP) levels were dysregulated.

Conclusion

This meta-analysis helps to clarify the profile of oxidative stress and antioxidant state markers in OLP patients although existing evidence is rather heterogeneous and many studies are affected by several limitations. Larger and more standardized studies are warranted to ascertain whether these markers are potential causes or effects of OLP and whether antioxidant therapy improving oxidative stress will be useful.

Stress hormones promote DNA damage in human oral keratinocytes

Chronic stress increases the systemic levels of stress hormones norepinephrine and cortisol. As well as tobacco-specific carcinogen NNK (4-(methylnitrosamine)-1-(3-pyridyl)-1-butanone), they can induce expressive DNA damage contributing to the cancer development. However, it is unknown whether stress hormones have genotoxic effects in oral keratinocytes. This study investigated the effects of stress hormones on DNA damage in a human oral keratinocyte cell line (NOK-SI). NOK-SI cells stimulated with norepinephrine or cortisol showed higher DNA damage compared to untreated cells. Norepinephrine-induced DNA damage was reversed by pre-treatment with beta-adrenergic blocker propranolol. Cells treated with NNK combined to norepinephrine displayed reduced levels of caspases 3 and 7. Cortisol also reduced the activity of pro-apoptotic enzymes. NNK or norepinephrine promoted single-strand breaks and alkali-label side breaks in the DNA of NOK-SI cells. Pre-treatment of cells with propranolol abolished these effects. Carcinogen NNK in the presence or absence of cortisol also induced DNA damage of these cells. The genotoxic effects of cortisol alone and hormone combined with NNK were blocked partially and totally, respectively, by the glucocorticoid receptor antagonist RU486. DNA damage promoted by NNK or cortisol and carcinogen combined to the hormone led to intracellular γH2AX accumulation. The effects caused by NNK and cortisol were reversed by propranolol and glucocorticoid receptor antagonist RU486, respectively. Propranolol inhibited the oxidation of basis induced by NNK in the presence of DNA-formamidopyrimidine glycosylase. DNA breaks induced by norepinephrine in the presence or absence of NNK resulted in higher 8OHdG cellular levels. This effect was also induced through beta-adrenergic receptors. Together, these findings indicate that stress hormones induce DNA damage of oral keratinocytes and could contribute to oral carcinogenesis.

Malondialdehyde, an Oxidative Stress Marker in Oral Squamous Cell Carcinoma-A Systematic Review and Meta-Analysis

Objective: To qualitative and quantitatively review published literature assessing the oxidative stress marker malondialdehyde (MDA) in oral squamous cell carcinoma (OSCC). Methodology: Pubmed (MeSH), Science Direct, Scopus, Web of Science, Willey Online Library, Cochrane, and Cross Reference were searched for studies assessing MDA levels in OSCC samples. Results: From the 1008 articles identified, 849 were excluded based on title and abstract screening due to duplication and irrelevance to the topic of interest. Full-text assessment of the remaining 159 articles led to the inclusion of only 46 articles that satisfied the selection criteria. Of these, only 26 studies had data compatible for quantitative analysis. The MDA levels in OSCC groups are significantly increased (p < 0.00001) in plasma, serum, and saliva samples in the majority of the studies evaluated. In contrast, MDA levels in OSCC tissue samples are significantly attenuated (p < 0.00001) compared to healthy controls, supported by fewer studies. Conclusions: The augmented MDA levels in plasma, serum, and saliva samples of the OSCC reflect the heightened oxidative stress level accurately. Further studies are required to understand the attenuated MDA levels in the tissue samples of OSCC. Correlation analysis between MDA levels with established clinicopathological prognostic markers could aid in formulating oxidative stress-based prognostication and treatment planning.

A Meta-Analysis in Assessing Oxidative Stress Using Malondialdehyde in Oral Submucous Fibrosis

Objective This study aimed to evaluate the oxidative stress (OS) marker Malondialdehyde (MDA) in oral submucous fibrosis with available literature.

Materials and Methods We conducted a literature search electronically in PubMed (MeSH), Science Direct, Scopus, and Google Scholar using specific keywords.

Results A systematic search in PubMed, Science Direct, and Google Scholar identified 334 articles. Of these, four were duplicate reports, and three were animal studies. After reading the abstracts of the collected articles, 288 articles were excluded for the following reasons: low quality, not relevant to the research question, or did not meet the inclusion criteria. The remaining 46 articles were chosen for full-text assessment. Finally, the present qualitative synthesis included 23 articles for evaluation. The selected studies in MDA analysis in a random-effects model showed higher heterogeneity (Q = 477.636, p < 0.001, I ² = 95.394%). The standard difference in mean MDA concentration between oral submucous fibrosis (OSMF) and healthy subjects was estimated as 2.73 nmol/mL (95% confidence interval: 2.08–3.38).

Conclusion The selected studies showed significantly higher MDA levels in various biological samples of patients with OSMF. Therefore, further studies are needed to estimate oxidative stress levels by using different biomarkers in OSMF to direct future therapy.

Ethanol-Induced Cell Damage Can Result in the Development of Oral Tumors

Simple Summary

Alcohol consumption is linked to 26.4% of all lip and oral cavity cancer cases worldwide. Despite this clear causal relationship, the exact molecular mechanisms by which ethanol damages cells are still under investigation. It is well-established that the metabolism of ethanol plays an important role. Ethanol metabolism yields reactive metabolites that can directly damage the DNA. If the damage is repaired incorrectly, mutations can be fixed in the DNA sequence. Whenever mutations affect key regulatory genes, for instance cell cycle regulating genes, uncontrolled cell growth can be the consequence. Recently, global patterns of mutations have been identified. These so-called mutational signatures represent a fingerprint of the different mutational processes over time. Interestingly, there were ethanol-related signatures discovered that did not associate with ethanol metabolism. This finding highlights there might be other molecular effects of ethanol that are yet to be discovered.

Abstract

Alcohol consumption is an underestimated risk factor for the development of precancerous lesions in the oral cavity. Although alcohol is a well-accepted recreational drug, 26.4% of all lip and oral cavity cancers worldwide are related to heavy drinking. Molecular mechanisms underlying this carcinogenic effect of ethanol are still under investigation. An important damaging effect comes from the first metabolite of ethanol, being acetaldehyde. Concentrations of acetaldehyde detected in the oral cavity are relatively high due to the metabolization of ethanol by oral microbes. Acetaldehyde can directly damage the DNA by the formation of mutagenic DNA adducts and interstrand crosslinks. Additionally, ethanol is known to affect epigenetic methylation and acetylation patterns, which are important regulators of gene expression. Ethanol-induced hypomethylation can activate the expression of oncogenes which subsequently can result in malignant transformation. The recent identification of ethanol-related mutational signatures emphasizes the role of acetaldehyde in alcohol-associated carcinogenesis. However, not all signatures associated with alcohol intake also relate to acetaldehyde. This finding highlights that there might be other effects of ethanol yet to be discovered.

Salivary diagnosis of oral cancers by salivary samples: a systematic literature review

The aim of this article is to carry out a systematic analysis of the literature concerning the diagnosis of oral cancers by salivary samples. Different biomarkers, produced by the tumor itself or by its environment, show significant variations in their concentration at the salivary level, correlated or not at the blood or tissue level. After studying 239 articles, we included 36 in this analysis. This allowed us to extract 46 potential molecules for salivary diagnostics. Only 26 demonstrated a good level of evidence. 8 clusters have also been proposed for better specificity and sensitivity. To date, the protocols of the studies carried out do not allow to affirm that one or more biomarkers are effective for a salivary diagnosis of oral cancers. Part of the results contradict or sometimes lack precision. In addition, the studies included here do not have a good methodological quality and do not always take into account other factors influencing the concentrations (systemic diseases, age, sex, tobacco, alcohol, etc.). Additional studies are still necessary, notably with larger groups of patients, representative of the general population and standardization of the protocols for the study and quantification of biomarkers.

The Implication of Reactive Oxygen Species and Antioxidants in Knee Osteoarthritis

Knee osteoarthritis (KOA) is a chronic multifactorial pathology and a current and essential challenge for public health, with a negative impact on the geriatric patient's quality of life. The pathophysiology is not fully known; therefore, no specific treatment has been found to date. The increase in the number of newly diagnosed cases of KOA is worrying, and it is essential to reduce the risk factors and detect those with a protective role in this context. The destructive effects of free radicals consist of the acceleration of chondrosenescence and apoptosis. Among other risk factors, the influence of redox imbalance on the homeostasis of the osteoarticular system is highlighted. The evolution of KOA can be correlated with oxidative stress markers or antioxidant status. These factors reveal the importance of maintaining a redox balance for the joints and the whole body's health, emphasizing the importance of an individualized therapeutic approach based on antioxidant effects. This paper aims to present an updated picture of the implications of reactive oxygen species (ROS) in KOA from pathophysiological and biochemical perspectives, focusing on antioxidant systems that could establish the premises for appropriate treatment to restore the redox balance and improve the condition of patients with KOA.

Evaluation of saliva glutathione, glutathione peroxidase, and malondialdehyde levels in head-neck radiotherapy patients

Background/aim

It is believed that radiotherapy has important effects on oxidant/antioxidant systems. Oxidative stress occurs when the balance between oxidant formation and antioxidant defense is disrupted in favor of oxidants. The aim of this study was to determine the biochemical changes in saliva pre- and postradiotherapy in head-neck radiotherapy patients and to find out the effects of radiation on glutathione (GSH), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels in saliva.

Materials and methods

This study included 16 patients undergoing head-neck radiotherapy in Atatürk University Research Hospital. The levels of GSH, GSH-Px, and MDA were measured in saliva samples taken from the patients pre- and postradiotherapy. The same biochemical parameters were also measured in saliva samples from 30 healthy individuals who did not undergo head-neck radiotherapy. The data obtained were analyzed using the paired t-test and the Mann–Whitney U test.

Results

When the levels of GSH (P > 0.05), GSH-Px (P > 0.05), and MDA (P < 0.05) in saliva were compared pre- and postradiotherapy in the patient group, the only significant increase was detected in the MDA level postradiotherapy. When the pre- and postradiotherapy levels of saliva GSH (P < 0.01, P < 0.001, respectively), GSH-Px (P > 0.05, P < 0.05, respectively), and MDA (P < 0.01, P < 0.001, respectively) were compared with those of the control group, it was revealed that the GSH level was significantly lower and the MDA level was significantly higher in both pre- and postradiotherapy compared to the control group. Also, only the postradiotherapy saliva GSH-Px level was found to be significantly lower than the control group.

Conclusion

These findings show that the changes in saliva GSH, GSH-Px, and MDA levels in patients with head-neck malignity intensified due to radiation.

Diagnostic and prognostic ability of salivary MMP-9 for oral squamous cell carcinoma: A pre-/post-surgery case and matched control study

Over 90% of oral cancers are oral squamous cell carcinoma (OSCC). Hitherto, early detection marker for OSCC has not been available. Hence, this study aimed to evaluate the diagnostic and prognostic ability of salivary matrix-metalloproteinase-9 (MMP-9) and 8-hydroxydeoxyguanosine (8-OHdG) for OSCC. Total of 318 participants with 106 cases and 212 controls were included: OSCC cases were from Seoul National University Dental Hospital and age, sex, and smoking matched controls were from Yangpyeong cohort. Unstimulated saliva was collected to determine MMP-9 and 8-OHdG using sensitive enzyme-linked immunosorbent assay. Multivariable linear regression and analysis of covariance (ANCOVA) were applied to evaluate the adjusted association of markers with OSCC. Wilcoxon sign rank sum test and Friedman test for median were applied to evaluate follow-up level of MMP-9 after surgery. Receiver operating characteristic curve was obtained for diagnostic ability. Salivary MMP-9 was associated with OSCC (ANCOVA and multivariable linear regression, p<0.05), while 8-OHdG was not. The diagnostic ability of MMP-9 was area under curve of 0.96 (100% specificity and 89.6% sensitivity, p<0.001). MMP-9 decreased dramatically after tumor surgery (p<0.05). Salivary MMP-9 could be a critical diagnostic and prognostic marker for OSCC.

Micronutrients Profile in Oral Lichen Planus: a Review Literature

Oral lichen planus (OLP) is a relatively common chronic inflammatory disease. The micronutrients are critical factors in health of oral mucous and proper function of immune system. There have not been any review articles for evaluating trace element levels before and after standard treatments of OLP. The purpose of this study is to provide complete review of the association of micronutrients with OLP. Databases including PubMed, Google Scholar, Scopus, and Embase (Ovid) with keywords of oral lichen planus, OLP, oral disorder, micronutrients, trace element, nutrient element, antioxidant, oxidative stress, malnutrition, and essential trace elements, without time limitation (1900-2019) were searched to collect data on related articles. Total number of 58 original articles including 12 randomized clinical trials, 41 case-control, 4 case reports, and 1 cell line research were reviewed in this study. Lower levels of iron and its associated markers, such as hemoglobin and ferritin, increased levels of TIBC; reduced levels of zinc, calcium, vitamin D, vitamin B12, folic acid, and antioxidants such as vitamins C and E; and increased levels of oxidants and homocysteine, have been reported in OLP patients.

Serum Vitamin Profile in Oral Lichen Planus Patients in Southwest of Iran

Introduction

Oral lichen planus (OLP) is a chronic mucocutaneous disease. It is mainly an immune system-related disorder. Vitamins can modulate immune system functions, and thus, vitamin deficiency might have roles in exacerbating OLP. We aim to determine the serum levels of vitamins A, B12, C, D3, and E in OLP patients.

Methods and Materials

34 OLP patients referred to Shiraz Dental School entered the study. Blood samples were collected and levels of A, B12, C, D3, and E vitamins were measured in serum. 43 healthy people were also included as the control group. Serum levels of vitamins were measured by HPLC (A, B12, D3, and E) and Kiazist analyzing kit (vitamin C).

Results

Most of the patients were female (62.3%), and the mean age of patients was 48.03 ± 11.57. Serum levels of vitamins A, C, and E were lower in OLP patients in comparison with the healthy group; however, the difference was not significant. Vitamins B12 and D3 were higher in the OLP group but the difference was not significant.

Conclusion

Serum levels of vitamins A, B12, C, D3, and E do not have a significant difference in OLP patients and healthy groups. These vitamins may not have a considerable role in OLP pathogenesis in the southwest of Iran.

Diagnostic and Prognostic Value of Salivary Biochemical Markers in Oral Squamous Cell Carcinoma

The purpose of the work is a comprehensive assessment of biochemical saliva markers for the diagnosis and prognosis of oral cancer. The group of patients included 68 patients with oral squamous cell carcinoma, 50 with non-cancerous diseases of the oral cavity, and 114 healthy volunteers. Before the start of treatment, 23 biochemical parameters of saliva were determined. Participants were monitored for six years to assess survival rates. The statistical analysis was performed by means of Statistica 10.0 and R package. A complex of metabolic changes occurring in saliva in oral cancer is described. It was shown that none of the studied parameters could be used to diagnose oral cancer in an independent variant; the use of combinations of parameters is more informative. The high prognostic value of the content of malondialdehyde (MDA) and the Na/K-ratio in saliva before treatment was established. Thus, the content of MDA ˂ 7.34 nmol/mL and the Na/K-ratio > 1.09 c.u. is a prognostically unfavorable factor (HR = 7.88, 95% CI 1.10-54.62, p = 0.01876), which may be useful for optimizing the treatment of patients with oral cancer. It has been shown that saliva has great potential for the development of diagnostic and prognostic tests for oral cancer.

Oral Submucous Fibrosis: A Review on Biomarkers, Pathogenic Mechanisms, and Treatments

Oral submucous fibrosis (OSF) is a collagen deposition disorder that affects a patient’s oral function and quality of life. It may also potentially transform into malignancy. This review summarizes the risk factors, pathogenic mechanisms, and treatments of OSF based on clinical and bio-molecular evidence. Betel nut chewing is a major risk factor that causes OSF in Asia. However, no direct evidence of arecoline-induced carcinogenesis has been found in animal models. Despite identification of numerous biomarkers of OSF lesions and conducting trials with different drug combinations, clinicians still adopt conservative treatments that primarily focus on relieving the symptoms of OSF. Treatments focus on reducing inflammation and improving mouth opening to improve a patient’s quality of life. In conclusion, high-quality clinical studies are needed to aid clinicians in developing and applying molecular biomarkers as well as standard treatment guidelines.

Salivary LDH in oral cancer and potentially malignant disorders: A systematic review and meta-analysis

OBJECTIVES

To evaluate whether salivary lactate dehydrogenase (LDH) levels are increased in patients with oral cancer (OC) or oral potentially malignant disorders (OPMD) when compared to a healthy control group (CG).

MATERIAL AND METHODS

We conducted a comprehensive search of specialized databases (PubMed/MEDLINE, The Cochrane Library, Web of Science, Scopus, and OpenGrey), including observational analytical studies evaluating the salivary LDH levels (in UI/L or μ/L) in OC or OPMD patients and compared them with a CG.

RESULTS

Thirteen case-control studies were included. A total of 755 patients were evaluated, including 303 OC cases, 149 OPMD cases, and 303 controls. The meta-analysis showed that LDH levels were higher within the OC group than the CG (SMD 9.49; 95% CI 6.97-12; p = .00001). Patients with oral leucoplakia (SMD 11.67; 95% CI 1.01-22.33; p = .03) and oral submucous fibrosis (SMD 25.83; 95% CI -1.74-53.40; p = .07) also presented higher levels than the CG. In addition, OC patients had higher salivary LDH levels than oral leucoplakia patients (SMD 5.62; 95% CI 2.14-9.11; p = .002). Heterogeneity was high across all the evaluated studies.

CONCLUSIONS

The determination of salivary LDH may be a useful method for screening and tracking OC and OPMD, but new protocolized studies are required to establish precise cutoff values.

Immunohistochemical detection of 8-hydroxydeoxyguanosine: A biomarker of oxidative DNA damage in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSMF) is one of the common potentially malignant disorders prevailing in India. The primary etiological factors include tobacco and arecanut, which contain numerous reactive oxygen species (ROS). ROS attack guanine bases in DNA and form 8-hydroxydeoxyguanosine (8-OHdG), which can be detected in patients who have diseases associated with oxidative stress. The oxidative DNA damage produced by oxidative stress may induce malignant transformation.

AIM

The aim of the present study is to detect the expression of 8-OHdG in OSMF patients and compare the expression within different grades of OSMF and also normal buccal mucosa.

MATERIALS AND METHODS

A total of 30 samples were examined for the immunohistochemical expression of 8-OHdG. The control group included 10 formalin-fixed paraffin-embedded tissue blocks of the normal buccal mucosa. The study group includes 20 cases of formalin-fixed paraffin-embedded tissue blocks of OSMF (5 cases in each grade of very early, early, moderately advanced and advanced cases of OSMF). Three-micron thick tissue sections were made from each sample and stained with 8-OHdG antibody. The results were statistically analyzed using Kruskal-Wallis and Mann-Whitney U test.

RESULTS

Statistically significant difference exists in the intensity of 8-OHdG expression between the study groups. The P-value obtained was <0.001, which was highly statistically significant.

CONCLUSION

The present study is the first attempt to evaluate the expression of 8-OHdG in tissue samples of OSMF that revealed the role of free radicals and oxidative DNA damage in these patients. Further research with larger sample size, clinicopathologic correlation and long-term follow-up will shed more light on the pathogenesis of OSMF. It will also be useful for the development of new therapeutic strategies targeting treatment modalities for OSMF.

Discrimination of oral squamous cell carcinoma from oral lichen planus by salivary metabolomics

OBJECTIVE

This study was conducted to distinguish salivary metabolites in oral squamous cell carcinoma (OSCC) from those in oral lichen planus (OLP) to identify practical biomarkers for the discrimination of OSCC from OLP.

SUBJECTS AND METHODS

Whole unstimulated saliva samples were collected from patients with OSCC (n = 34) and OLP (n = 26). Hydrophilic metabolites in the saliva samples were comprehensively analysed by capillary electrophoresis mass spectrometry. To evaluate the discrimination ability of a combination of multiple markers, a multiple logistic regression (MLR) model was developed to differentiate OSCC from OLP.

RESULTS

Fourteen metabolites were found to be significantly different between the OSCC and OLP groups. Among them, indole-3-acetate and ethanolamine phosphate were used to develop the MLR model. The combination of these two metabolites showed a high area under the receiver operating characteristic curve (0.856, 95% confidential interval: 0.762-0.950; p < .001) for discriminating OSCC from OLP.

CONCLUSIONS

We identified salivary metabolites for discerning between OSCC and OLP, which is clinically important for detecting the malignant transformation of OLP by both dentists and oral surgery specialists. Our candidate salivary metabolites show potential for non-invasive screening of OSCC versus OLP.

Oral Submucous Fibrosis: A Review on Etiopathogenesis, Diagnosis, and Therapy

Oral submucous fibrosis (OSF) is characterized by abnormal collagen deposition. It is a precancerous disorder and transforms into a malignant tumor in 1.5–15% of all cases. Symptoms include submucous fibrosis, ulceration, xerostomia, a burning sensation, and restricted mouth opening. All of these greatly interfere with patient quality of life. The present review introduces OSF from a molecular perspective and summarizes what is known about its underlying mechanisms, diagnostic biomarkers, and therapeutic interventions. In addition to the aggressive treatment of OSF, its prevention is also important. Future research should, therefore, focus on improving the oral health literacy of the patients susceptible to OSF.

Effect of short-term mechanical stimulation on the salivary concentrations of vitamin C, vitamin E, total antioxidant capacity and total oxidant status

Oxidative stress biomarkers of oral and systemic diseases can be found in saliva. However, there is no uniformity for the saliva collection time in these kinds of analyses and saliva composition may change because of mechanical stimulation. Therefore, the aim of this work was to determine the effect of mechanical stimulation for 10 min on the concentrations of vitamin C, vitamin E, total antioxidants and total oxidants in saliva. Saliva samples from individuals of both sexes, aged between 18 and 38 years, were collected for 10 min at 2 minintervals. Saliva flow rate in each 2 min period was measured, as well the total oxidant state, the total antioxidant capacity, vitamin C and vitamin E concentrations. All analyses were performed in triplicate and were determined using colorimetric tests. The results were analysed using t-test, Friedman's test and analysis of variance (ANOVA) for repeated measures. Mauchly's sphericity test was applied and, if necessary, technical corrections were made using the Greenhouse-Geisser test. We found no significant difference between the amounts of saliva produced across the collection times. Total oxidant status, total antioxidant capacity, vitamin C and vitamin E concentrations remained stable. Based on our findings, saliva can be collected for 10 min or less with masticatory stimulation without any variations in the concentration of the variables analysed. However, we suggest using saliva samples after two minutes of mechanical stimulation.

DNA damage in obesity: Initiator, promoter and predictor of cancer

Epidemiological evidence linking obesity with increased risk of cancer is steadily growing, although the causative aspects underpinning this association are only partially understood. Obesity leads to a physiological imbalance in the regulation of adipose tissue and its normal functioning, resulting in hyperglycaemia, dyslipidaemia and inflammation. These states promote the generation of oxidative stress, which is exacerbated in obesity by a decline in anti-oxidant defence systems. Oxidative stress can have a marked impact on DNA, producing mutagenic lesions that could prove carcinogenic. Here we review the current evidence for genomic instability, sustained DNA damage and accelerated genome ageing in obesity. We explore the notion of genotoxicity, ensuing from systemic oxidative stress, as a key oncogenic factor in obesity. Finally, we advocate for early, pre-malignant assessment of genome integrity and stability to inform surveillance strategies and interventions.

Mitochondrial dysfunction and oxidative stress in aging and cancer

Aging and cancer are the most important issues to research. The population in the world is growing older, and the incidence of cancer increases with age. There is no doubt about the linkage between aging and cancer. However, the molecular mechanisms underlying this association are still unknown. Several lines of evidence suggest that the oxidative stress as a cause and/or consequence of the mitochondrial dysfunction is one of the main drivers of these processes. Increasing ROS levels and products of the oxidative stress, which occur in aging and age-related disorders, were also found in cancer. This review focuses on the similarities between ageing-associated and cancer-associated oxidative stress and mitochondrial dysfunction as their common phenotype.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.

Use of Saliva Biomarkers to Monitor Efficacy of Vitamin C in Exercise-Induced Oxidative Stress

Saliva is easily obtainable for medical research and requires little effort or training for collection. Because saliva contains a variety of biological compounds, including vitamin C, malondialdehyde, amylase, and proteomes, it has been successfully used as a biospecimen for the reflection of health status. A popular topic of discussion in medical research is the potential association between oxidative stress and negative outcomes. Systemic biomarkers that represent oxidative stress can be found in saliva. It is unclear, however, if saliva is an accurate biospecimen as is blood and/or plasma. Exercise can induce oxidative stress, resulting in a trend of antioxidant supplementation to combat its assumed detriments. Vitamin C is a popular antioxidant supplement in the realm of sports and exercise. One potential avenue for evaluating exercise induced oxidative stress is through assessment of biomarkers like vitamin C and malondialdehyde in saliva. At present, limited research has been done in this area. The current state of research involving exercise-induced oxidative stress, salivary biomarkers, and vitamin C supplementation is reviewed in this article.

Inhibition of Nox1 induces apoptosis by attenuating the AKT signaling pathway in oral squamous cell carcinoma cell lines

NADPH oxidases, also known as the Nox family, are major sources of reactive oxygen species generation that regulate redox-sensitive signaling pathways. Recent studies have implicated the Nox family in cancer development and progression. However, the involvement of its members in the development of oral squamous cell carcinoma (OSCC) remains to be elucidated. To clarify this issue, we first analyzed mRNA expression of Nox/Duox family members (Nox1, Nox2, Nox3, Nox4, Nox5, Duox1 and Duox2) in five OSCC cell lines. Nox1 and Nox4 mRNAs were highly expressed in four OSCC cell lines. Western blot analysis revealed that the protein expression level of Nox1 was higher than that of Nox4 in the OSCC cell lines. In addition, knockdown of Nox1, but not Nox4, significantly suppressed cell viability and induced apoptosis in the HSC-2 and HSC-3 cells. We also found that a specific AKT inhibitor, perifosine, dose-dependently suppressed OSCC cell growth. Notably, Nox1 knockdown significantly attenuated the phosphorylation level of AKT. Furthermore, both Nox1 knockdown and perifosine treatment markedly enhanced the cisplatin-induced cytotoxic effect. Taken together, our results highlight that the Nox1/AKT signaling pathway plays an important role in cell survival in OSCC cells.