8-hydroxy-deoxyguanosine levels in gingival crevicular fluid and saliva in patients with chronic periodontitis after initial periodontal treatment

Ganoderma Microsporum Immunomodulatory Protein Alleviates Inflammaging and Oxidative Stress in Diabetes-Associated Periodontitis via Nrf2 Signaling Activation: An In Vitro Study

Periodontitis, characterized by inflammation and loss of periodontal tissue, is a significant health complication for individuals with diabetes mellitus (DM). Buildup of advanced glycation end-products (AGEs) in DM poses an increased risk of periodontitis via inflammaging. Ganoderma immunomodulatory protein (GMI) shows promise in suppressing inflammaging by mitigating oxidative stress and inflammation via Nrf2 modulation. However, its specific protective effects are not fully understood. Thus, this study aimed to investigate GMI's anti-inflammaging properties and its underlying mechanism in diabetic-associated periodontitis (DP). We first simulated DP by culturing human gingival fibroblasts (HGFs) with AGEs and lipopolysaccharides from P. gingivalis (LPS). We then evaluated the impact of GMI on cell proliferation, migration and wound healing. Additionally, we assessed GMI's effects on the components of inflammaging such as reactive oxygen species (ROS) formation, cellular senescence expression, IL-6 and IL-8 secretions, and NF-κB phosphorylation. Next, we explored whether GMI's anti-inflammaging effects are mediated through the Nrf2 pathway by evaluating Nrf2 and HO-1, followed by the assessment of IL-6 and IL-8 post-Nrf2 knockdown. Our findings revealed that GMI treatment suppressed ROS production, cell senescence, IL-6 and IL-8 and NF-κB phosphorylation. Furthermore, GMI upregulated Nrf2/HO-1 expression and its protective effects were reversed when Nrf2 was knocked down. In conclusion, GMI exerts its anti-inflammaging effect via the modulation of the Nrf2/NF-κB signaling axis in DP in vitro, highlighting its potential as an effective adjunct treatment for diabetes-related periodontitis.

Impact of Periodontitis on Endothelial Risk Dysfunction and Oxidative Stress Improvement in Patients with Cardiovascular Disease

Periodontitis is a multifactorial chronic inflammatory disease that affects the periodontium and overall oral health and is primarily caused by a dysbiotic gingival biofilm, which includes, among others, Gram-negative bacteria such as Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Tannerella forsythensis that colonize gingival tissues and that can lead, if not properly treated, to periodontal tissue destruction and tooth loss. In the last few decades, several large-scale epidemiological studies have evidenced that mild and severe forms of periodontitis are strictly bilaterally associated with several cardiovascular diseases (CVDs), stroke, and endothelial dysfunction. Specifically, it is hypothesized that patients with severe periodontitis would have compromised endothelial function, a crucial step in the pathophysiology of atherosclerosis and several CVD forms. In this regard, it was postulated that periodontal treatment would ameliorate endothelial dysfunction, hence bolstering the notion that therapeutic approaches targeted at diminishing cardiovascular risk factors and different forms of periodontal treatment could improve several CVD biomarker outcomes in the short- and long-term in CVD patients. The aim of this review is to update and analyze the link between periodontitis and CVD, focusing on the inflammatory nature of periodontitis and its correlation with CVD, the effects of periodontal therapy on endothelial dysfunction and oxidative stress, and the impact of such therapy on CVD biomarkers and outcomes. The article also discusses future research directions in this field.

Using 8-Hydroxy-2'-Deoxiguanosine (8-OHdG) as a Reliable Biomarker for Assessing Periodontal Disease Associated with Diabetes

In recent years, research has shown that oxidative stress plays a significant role in chronic inflammatory conditions. The alteration of the oxidant/antioxidant balance leads to the appearance of free radicals, important molecules involved in both diabetes mellitus and periodontal disease. Diabetes is considered to be one of the major risk factors of periodontal disease and the inflammation characterizing this condition is associated with oxidative stress, implicitly resulting in oxidative damage to DNA. 8-Hydroxydeoxyguanosine (8-OHdG) is the most common stable product of oxidative DNA damage caused by reactive oxygen species, and its levels have been reported to increase in body fluids and tissues during inflammatory conditions. 8-OHdG emerges as a pivotal biomarker for assessing oxidative DNA damage, demonstrating its relevance across diverse health conditions, including neurodegenerative disorders, cancers, inflammatory conditions, and periodontal disease. Continued research in this field is crucial for developing more precise treatments and understanding the detailed link between oxidative stress and the progression of periodontitis. The use of the 8-OHdG biomarker in assessing and managing chronic periodontitis is an area of increased interest in dental research, with the potential to provide crucial information for diagnosis and treatment.

Saliva biomarkers in oral disease

Saliva is a versatile biofluid that contains a wide variety of biomarkers reflecting both physiologic and pathophysiologic states. Saliva collection is noninvasive and highly applicable for tests requiring serial sampling. Furthermore, advances in test accuracy, sensitivity and precision for saliva has improved diagnostic performance as well as the identification of novel markers especially in oral disease processes. These include dental caries, periodontitis, oral squamous cell carcinoma (OSCC) and Sjögren's syndrome (SS). Numerous growth factors, enzymes, interleukins and cytokines have been identified and are the subject of much research investigation. This review highlights current procedures for successful determination of saliva biomarkers including preanalytical factors associated with sampling, storage and pretreatment as well as subsequent analysis. Moreover, it provides an overview of the diagnostic applications of these salivary biomarkers in common oral diseases.

Nrf2: a dark horse in doxorubicin-induced cardiotoxicity

Being a broad-spectrum anticancer drug, doxorubicin is indispensable for clinical treatment. Unexpectedly, its cardiotoxic side effects have proven to be a formidable obstacle. Numerous studies are currently devoted to elucidating the pathological mechanisms underlying doxorubicin-induced cardiotoxicity. Nrf2 has always played a crucial role in oxidative stress, but numerous studies have demonstrated that it also plays a vital part in pathological mechanisms like cell death and inflammation. Numerous studies on the pathological mechanisms associated with doxorubicin-induced cardiotoxicity demonstrate this. Several clinical drugs, natural and synthetic compounds, as well as small molecule RNAs have been demonstrated to prevent doxorubicin-induced cardiotoxicity by activating Nrf2. Consequently, this study emphasizes the introduction of Nrf2, discusses the role of Nrf2 in doxorubicin-induced cardiotoxicity, and concludes with a summary of the therapeutic modalities targeting Nrf2 to ameliorate doxorubicin-induced cardiotoxicity, highlighting the potential value of Nrf2 in doxorubicin-induced cardiotoxicity.

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.

The role of Nrf2 in periodontal disease by regulating lipid peroxidation, inflammation and apoptosis

Nuclear factor E2-related factor 2(Nrf2) is a transcription factor that mainly regulates oxidative stress in the body. It initiates the expression of several downstream antioxidants, anti-inflammatory proteins and detoxification enzymes through the Kelch-like ECH-associating protein 1 (Keap1) -nuclear factor E2-related factor 2(Nrf2) -antioxidant response element (ARE) signaling pathway. Its anti-apoptosis, anti-oxidative stress and anti-inflammatory effects have gradually become the focus of periodontal disease research in recent years. In this paper, the structure and function of Nrf2 pathway and its mechanism of action in the treatment of periodontitis in recent years were analyzed and summarized, so as to further clarify the relationship between Nrf2 pathway and oxidative stress in the occurrence and development of periodontitis, and to provide ideas for the development of new treatment drugs targeting Nrf2 pathway.

Salivary biomarkers as key to monitor personalized oral healthcare and precision dentistry: A scoping review

Personalized Oral Healthcare has recently become the new trend word in medicine and dentistry. In this context, saliva diagnostics using various biomarkers seem to be the gateway to personalized dental diagnostics and therapy. But the terminology is not (yet) uniformly defined, furthermore it is unclear to what extent which salivary markers play a relevant role in the therapeutic decision making. In this Scoping Review, an electronic search was conducted in PubMed and Web of Science databases using medical subject headings (MESH terms) “saliva”, “biomarker”, “personality/persons”, and “dentistry”. Only human studies were included, in which repeated salivary measurements were performed to analyze monitoring effects with at least ten patients per group. PRISMA-ScR and Tricco guidelines were followed: (i) to examine what salivary biomarkers have been explored in terms of personalized oral healthcare and precision dentistry, (ii) to investigate the clinical relevance for oral health and its correlation to systemic health, and (iii) to summarize an outlook for future developments based on these results. Out of 899 studies, a total of 57 were included for data extraction in this Scoping Review, mainly focusing on periodontal therapy and patient monitoring. Salivary biomarkers have shown the potential to change the field of dentistry in all dental disciplines as a key for personalized workflows. The increasing interest in dental research is obvious, demonstrated by the growing number of publications in recent years. At this time, however, the predominant discipline is periodontology, which allows biomarker-based monitoring of the disease prevention and progression. The studies included showed heterogeneous methods using manifolds biomarkers. Therefore, no uniformly accepted concept can be presented today. Further clinical research with well-defined outcomes including standardized procedures is necessary.

Effects of Nonsurgical Periodontal Therapy on Salivary 8-Hydroxy-Deoxyguanosine Levels and Glycemic Control in Diabetes Mellitus Type 2 Patients

Diabetes and periodontitis are complex chronic diseases that are potentially interrelated, as well as associated with oxidative stress. Thus, the aim of the present study was to evaluate the influence of nonsurgical periodontal treatment on salivary 8-hydroxy-deoxyguanosine (8-OHdG) levels and glycemic control in patients suffering from both diabetes mellitus type 2 (DM2) and periodontitis. The study sample included 53 DM2 patients, while 31 systemically healthy patients served as controls. Participants in both groups suffered from periodontitis of comparable severity. Periodontal clinical parameters, namely plaque index (PI), gingival index (GI), papilla bleeding index (PBI), probing pocket depth (PPD), and clinical attachment level (CAL) were recorded, along with salivary 8-OHdG levels and glycated hemoglobin (HbA1c). Levels of 8-OHdG were analyzed by ELISA. All aforementioned parameters were evaluated prior to commencing the study and at 90-day follow-up upon nonsurgical periodontal therapy completion. At baseline, salivary levels of 8-OHdG in DM2 patients were significantly higher (1.17 ng/mL) than those measured for the control group (0.75 ng/mL) and showed significant positive correlation with GI and PPD (p < 0.05). Three months after nonsurgical periodontal therapy, the salivary 8-OHdG levels were significantly reduced in DM2 patients (p < 0.05). Analysis results also revealed statistically significant changes in all measured clinical parameters between baseline and three-month follow-up in both groups (p < 0.05). Upon treatment completion, a decline in the HbA1c level was noted in DM group, but it did not reach statistical significance (p > 0.05). It can be concluded that DM2 patients benefit from non-surgical periodontal therapy, as indicated by a marked reduction in their salivary 8-OHdG level and a modest improvement in glycemic control. Short-term clinical benefits noted in the DM group were similar to those observed in the non-diabetic periodontal patients.

Evaluation of the effect of nonsurgical periodontal therapy on malondialdehyde and 8-hydroxy deoxyguanosine levels in chronic periodontitis

Background

Reactive oxygen species released on stimulation by periodontal pathogens cause oxidation of biomolecules and play significant role in periodontal disease pathogenesis.

Aim

This study aimed to evaluate the levels of oxidative by-products malondialdehyde (MDA) and 8-hydroxy deoxyguanosine (8-OHdG) as biomarkers in chronic periodontitis patients compared to healthy as well as before and after nonsurgical periodontal therapy. The correlation between biomarkers and clinical attachment level was also evaluated.

Settings and Design

A total of 112 subjects were included in this study. The subjects were divided into two groups (Group I included 56 healthy subjects and Group II constituted 56 chronic periodontitis patients) on the basis of clinical periodontal parameters.

Materials and Methods

Group I subjects received no treatment and were evaluated once only for clinical and oxidative stress biomarker parameters. Nonsurgical periodontal therapy was carried out in Group II patients and they were evaluated at baseline and 3 months after therapy.

Results

Both salivary and serum levels of MDA and 8-OHdG were found to be increased in chronic periodontitis patients as compared to healthy subjects. After nonsurgical periodontal therapy, the levels of MDA and 8-OHdG significantly reduced. Linear correlation between clinical attachment level and oxidative stress parameters was found to be positive and highly significant.

Conclusion

It can be concluded that periodontal therapy is effective in improving the oxidative stress condition.

Salivary and gingival CXCL8 correlation with periodontal status, periodontal pathogens and smoking

OBJECTIVES

Neutrophil granulocytes have been proposed to play a major role in the mediation of periodontitis-associated tissue destruction. Their recruitment and activation are regulated by the chemokine CXCL8. This study aimed to delineate the dependency of CXCL8-expression in gingival crevicular fluid (GCF) and saliva on periodontal status, bacterial infection and smoking, in patients with periodontitis.

METHODS

The study cohort comprised 279 subjects with untreated periodontitis. Probing pocket depth (PPD), gingival recession, bleeding on probing (BOP), plaque index, and bone loss were evaluated. CXCL8 was determined in saliva and GCF using flow cytometry.

RESULTS

Considering the entire study sample, CXCL8 levels were correlated with the mean PPD (ρ=0.131; p=0.029), severity of periodontitis (ρ=0.121; p=0.043), BOP (ρ=0.204; p=0.001) and smoking (ρ=-0.219; p<0.0001) in GCF; and, in whole saliva, with mean PPD (ρ=0.154; p=0.010) severity of periodontitis (ρ=0.140; p=0.020), gender (ρ=0.178; p=0.003) and smoking (ρ=-0.156; p=0.010). Subgroup analysis among non-smokers revealed significantly higher amounts of CXCL8 in GCF (p=0.012) and saliva (p=0.026) comparing subjects with mean PPD ≤3mm and >3mm.

CONCLUSION

The current study revealed a strong dependency of CXCL8-expression in GCF on the severity and activity of periodontal disease. Smoking causes a significant reduction of CXCL8-expression in saliva and GCF.

Saliva as a Source of Biomarkers for Periodontitis and Periimplantitis

Saliva has the potential to be used as a diagnostic and monitoring tool for various diseases if biomarkers of an adequate sensitivity and specificity could be identified. Several reviews and even meta-analyses have been performed in recent years, which have found some candidate biomarkers for periodontitis, like macrophage inflammatory protein-1 alpha, interleukin-1ß, interleukin-6, matrix metalloproteinase-8, or hemoglobin. However, none of those are currently in use to replace conventional periodontal diagnostics with a periodontal probe. For periimplantitis, to date, heterogeneity of different study protocols and implant types did not permit to discover clear biomarkers, which were able to distinguish between healthy and diseased implants. Few proinflammatory cytokines, similar to periodontitis, have been characterized as adjunct tools to clinical diagnosis. The additional determination of antimicrobial peptides, bone turnover markers, and bacteria could help to enhance sensitivity and specificity in a combined model for periodontitis and periimplantitis. Furthermore, proteomic approaches might be preferred over single biomarker determinations. A global consensus is also needed to harmonize salivary sampling methods as well as procedures of biomarker analysis to ensure future comparability.

Free amino acid composition of saliva in patients with healthy periodontium and periodontitis

OBJECTIVES

To identify and compare the free amino acids in the saliva of periodontitis patients and healthy individuals and to assess their levels in different periodontal disease types.

MATERIALS AND METHODS

There were three groups: healthy individuals (control (C); n = 20), Stage III Grade B generalized periodontitis (GP-B; n = 20), and Stage III Grade C generalized periodontitis (GP-C; n = 20). Clinical periodontal parameters were measured. Amino acid analysis of the saliva was accomplished by liquid chromatography-mass spectrometry (LC MS/MS), taking the mean concentration.

RESULTS

Citrulline and carnosine concentrations were significantly higher in patients with periodontitis than in the control group (p < 0.017). Methionine, glutamic acid, and arginine showed significantly higher concentrations in GP-C, whereas proline and tryptophan showed higher concentrations in the GP-B group (p < 0.017). There was a significant correlation between methionine, citrulline, arginine, and carnosine and clinical periodontal parameters.

CONCLUSIONS

Our results demonstrate that periodontal status and disease type can result in variations in salivary amino acid (AA) content in correlation with clinical inflammatory signs. The significant correlation of methionine, citrulline, carnosine, and arginine with clinical parameters, regardless of systemic status, suggests that the levels of different salivary free AAs play roles in periodontitis.

CLINICAL RELEVANCE

Salivary free AAs may be suggested as a potential diagnostic compound in patients with periodontitis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04642716.

Antioxidant effect of caffeic acid phenethyl ester in experimentally induced periodontitis

OBJECTIVES

The aim of the present study was to evaluate the antioxidant effect of systemically administered caffeic acid phenethyl ester (CAPE) in periodontitis.

MATERIALS AND METHODS

Forty rats were randomly divided into four groups: control, lipopolysaccharide-induced experimental periodontitis (LPS), CAPE 5: LPS+5 μmol/kg/day CAPE, and CAPE 10: LPS+10 μmol/kg/day CAPE. Following lipopolysaccharide-induced experimental periodontitis, CAPE was administered intraperitoneally for 28 days. Gingival and serumal total antioxidant status (TAS) and total oxidant status (TOS) were analyzed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Gingival tissue TAS was significantly higher with CAPE application compared with the LPS group and was highest in the CAPE 10 group (p<0.05). Gingival tissue TOS was highest in the LPS group, and both of the CAPE dosages decreased the gingival tissue TOS, with the highest decrease in the CAPE 10 group (p<0.05). The differences were not significant for serumal TAS or TOS levels (p>0.05).

CONCLUSIONS

The effect of CAPE on increased TAS and decreased TOS levels in inflamed gingival tissue indicates the antioxidant therapeutic potential of CAPE in periodontitis.

CLINICAL RELEVANCE

Within the limitations of this study, CAPE may be suggested as an effective host modulator agent for reducing oxidative stress in gingival tissue and might be considered as an adjunctive therapy in periodontitis.

Metabolomics of gingival crevicular fluid to identify biomarkers for periodontitis: A systematic review with meta-analysis

The present systematic review aimed to examine periodontitis-specific biomarkers in the gingival crevicular fluid (GCF) that could have a diagnostic relevance, and to provide a qualitative assessment of the current literature. Metabolites are reliable indicators of pathophysiological statuses, and their quantification in the GCF can provide an outlook of the changes associated with periodontitis and have diagnostic value. Relevant studies identified from PubMed, Embase, Cochrane Library, and Scopus databases were examined to answer the following PECO question: "In systemically healthy individuals, can concentration of specific metabolites in the GCF be used to discriminate subjects with healthy periodontium (H) or gingivitis from patients with periodontitis (P) and which is the diagnostic accuracy?" Quality of included studies was rated using a modified version of the QUADOMICS tool. Meta-analysis was conducted whenever possible. After the screening of 1,554 titles, 15 studies were selected, with sample size ranging from 30 to 93 subjects. Eleven studies performed targeted metabolomics analysis and provided data for 10 metabolites. Among the most consistent markers, malondialdehyde levels were found higher in the P group compared with H group (SMD = 2.86; 95% CI: 1.64, 4.08). Also, a significant increase of 8-hydroxy-deoxyguanosine, 4-hydroxynonenal, and neopterin was detected in periodontally diseased sites, while glutathione showed an inverse trend. When considering data from untargeted metabolomic analysis in four studies, more than 40 metabolites were found significantly discriminant, mainly related to amino acids and lipids degradation pathways. Notably, only one study reported measures of diagnostic accuracy. Several metabolites were differentially expressed in GCF of subjects across different periodontal conditions, having a major potential for investigating periodontal pathophysiology and for site-specific diagnosis. Oxidative stress-related molecules, such as malondialdehyde and 8-hydroxy-deoxyguanosine, were the most consistently associated to periodontitis (PROSPERO CRD42020188482).

Biomarkers of nucleic acid oxidation - A summary state-of-the-art

Oxidatively generated damage to DNA has been implicated in the pathogenesis of a wide variety of diseases. Increasingly, interest is also focusing upon the effects of damage to the other nucleic acids, RNA and the (2′-deoxy-)ribonucleotide pools, and evidence is growing that these too may have an important role in disease. LC-MS/MS has the ability to provide absolute quantification of specific biomarkers, such as 8-oxo-7,8-dihydro-2′-deoxyGuo (8-oxodG), in both nuclear and mitochondrial DNA, and 8-oxoGuo in RNA. However, significant quantities of tissue are needed, limiting its use in human biomonitoring studies. In contrast, the comet assay requires much less material, and as little as 5 μL of blood may be used, offering a minimally invasive means of assessing oxidative stress in vivo, but this is restricted to nuclear DNA damage only. Urine is an ideal matrix in which to non-invasively study nucleic acid-derived biomarkers of oxidative stress, and considerable progress has been made towards robustly validating these measurements, not least through the efforts of the European Standards Committee on Urinary (DNA) Lesion Analysis. For urine, LC-MS/MS is considered the gold standard approach, and although there have been improvements to the ELISA methodology, this is largely limited to 8-oxodG. Emerging DNA adductomics approaches, which either comprehensively assess the totality of adducts in DNA, or map DNA damage across the nuclear and mitochondrial genomes, offer the potential to considerably advance our understanding of the mechanistic role of oxidatively damaged nucleic acids in disease.

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Oxidatively damaged nucleic acids are implicated in the pathogenesis of disease.

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LC-MS/MS, comet assay and ELISA are often used to study oxidatively damaged DNA.

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Urinary oxidatively damaged nucleic acids non-invasively reflect oxidative stress.

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DNA adductomics will aid understanding the role of ROS damaged DNA in disease.

THE INFLUENCE OF PERIODONTAL DISEASE TREATMENT ON 8-HYDROXY-DEOXYGUANOSINE CONCENTRATIONS IN SALIVA AND PLASMA OF CHRONIC PERIODONTITIS PATIENTS

The 8-hydroxy-deoxyguanosine (8-OHdG) is one of the customary products of oxidized DNA. The purpose of this study was to compare salivary and plasma 8-OHdG concentrations in a group of chronic periodontitis patients to those measured in a group of patients with healthy periodontium, as well as to determine the impact of periodontal therapy on 8-OHdG concentrations in saliva and plasma in chronic periodontitis patients. The study sample comprised of 24 patients with chronic periodontitis and 16 periodontally healthy individuals. Plaque index, gingival index, papilla bleeding index, probing depth and clinical attachment level were indices used to determine patient periodontal status. Salivary and plasma 8-OHdG concentrations were determined by ELISA method. The salivary 8-OHdG concentration was statistically significantly higher in the group of periodontitis patients compared to periodontally healthy subjects. After initial periodontal therapy, the 8-OHdG concentration in saliva was significantly reduced in the periodontitis group (p=0.021). Differences in plasma 8-OHdG concentrations between the two groups did not reach statistical significance and no significant changes were noted in the periodontitis group following initial periodontal therapy. A higher salivary 8-OHdG concentration reflects increased oxidative stress caused by periodontal disease. Initial periodontal therapy may be helpful in reducing salivary 8-OHdG concentrations in chronic periodontitis patients.

Autophagy, One of the Main Steps in Periodontitis Pathogenesis and Evolution

Periodontitis represents a complex inflammatory disease that compromises the integrity of the tooth-supporting tissue through the interaction of specific periodontal pathogens and the host's immune system. Experimental data help to outline the idea that the molecular way towards periodontitis initiation and progression presents four key steps: bacterial infection, inflammation, oxidative stress, and autophagy. The aim of this review is to outline the autophagy involvement in the pathogenesis and evolution of periodontitis from at least three points of view: periodontal pathogen invasion control, innate immune signaling pathways regulation and apoptosis inhibition in periodontal cells. The exact roles played by reactive oxygen species (ROS) inside the molecular mechanisms for autophagy initiation in periodontitis still require further investigation. However, clarifying the role and the mechanism of redox regulation of autophagy in the periodontitis context may be particularly beneficial for the elaboration of new therapeutic strategies.

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.

Salivary 8-hydroxyguanosine levels in smokers and non-smokers with chronic periodontitis

This case-controlled clinical trial was performed on the salivary 8-hydroxyguanosine (8-OHdG) levels in smokers and non-smokers with chronic periodontitis after non-surgical periodontal therapy. Subjects (N = 40) with periodontitis (smokers and non-smokers) and with clinically healthy conditions (smokers and non-smokers) were assigned to this study. At baseline, clinical periodontal parameters (plaque index, gingival index, pocket probing depth and clinical attachment levels) were evaluated. Saliva samples were obtained pre- and post-treatment to quantify the 8-OHdG levels using Elisa technique. Subjects diagnosed with chronic periodontitis with smoking habit (CPs) and non-smokers (CPns) received scaling and root planing. In clinically healthy subjects with smoking habit (CHs) and non-smokers (CHns), only oral hygiene tutoring was performed. All clinical measurements and salivary collection were repeated in a 3-month recall interval. Data were analyzed using Anova, Tukey post hoc test and Mann-Whitney 'U' tests (P < 0.05). At baseline, CPs and CPns groups showed significantly higher PI, GI, PD and CAL values than those of CHns and CHs (P < 0.001). Baseline salivary levels of 8-OHdG were significantly higher in CPs group (14.775 pg/mL) (P < 0.001) compared to the other groups. All clinical parameters in chronic periodontitis group improved at the 3rd month recall interval, however, with regards to 8-OHdG values, the CP smoker category still had a higher level compared to CP non-smoker. This study reflects an on-going periodontal destructive status in smokers and salivary 8-OHdG levels could be recognized as an oxidative biomarker for determining periodontal tissue destruction.

Oxidative stress-related biomarkers in saliva and gingival crevicular fluid associated with chronic periodontitis: A systematic review and meta-analysis

AIM

Oxidative stress (OS) biomarkers have been detected in saliva and gingival crevicular fluid (GCF) during chronic periodontitis (CP) progression; however, the relationship between OS biomarkers and CP progression remains elusive. The purpose of this meta-analysis is to investigate the relationship between local OS biomarkers and CP.

METHODS

This review was conducted through a systematic search from three databases. Studies on CP participants were included as an experimental group, and studies on periodontally healthy (PH) participants were included as a control. Mean effects were expressed as standardized mean difference with their associated 95% confidence intervals.

RESULTS

From a total of 2,972 articles, 32 articles fulfilled the inclusion criteria. We found a significant decrease of total antioxidant capacity and a significant increase of malondialdehyde (MDA), nitric oxide, total oxidant status (TOS), and 8-hydroxy-deoxyguanosine levels in the saliva of CP patients. Moreover, we also found an elevation of MDA level in GCF of CP group when compared with the PH group. There were no significant differences of salivary and GCF superoxide dismutase levels, salivary glutathione peroxidase level, and GCF TOS level between two groups. However, a high heterogeneity was observed among evaluated studies.

CONCLUSIONS

Despite the limitations of this study, the result of our meta-analysis supported the rationale that there was a direct link between CP and OS-related biomarkers' levels in the local site, indicating the important role of OS in the onset and development of CP.

Impact of cigarette smoking and vaping on the outcome of full-mouth ultrasonic scaling among patients with gingival inflammation: a prospective study

OBJECTIVES

There are no studies that have assessed the oral soft tissue response to full-mouth ultrasonic scaling (FMUS) among cigarette-smokers (CS) (group 1), individuals vaping electronic-cigarettes (E-cigs) (group 2), and never-smokers (NS) (group 3). The aim was to assess the impact of cigarette smoking and vaping on periodontal tissues following FMUS.

MATERIALS AND METHODS

In a clinical prospective study, 89 male individuals were divided into three groups: CS (group 1), E-cig users (group 2), and NS (group 3). A questionnaire was used to gather demographic data and information regarding duration and daily frequency of CS and vaping. Full-mouth plaque index (PI), bleeding on probing (BOP), clinical attachment loss (AL), and probing depth (PD) were measured at baseline and 3 and 6 months after FMUS (without root surface debridement). Numbers of missing teeth (MT) were also recorded.

RESULTS

In groups 1, 2, and 3, 30, 28, and 31 individuals, respectively were included. In group 1, there was no statistically significant difference in mean PI and PD and numbers of sites with PD ≥ 4 mm at 6 months' follow-up compared with baseline and 3 months' follow-up. In groups 2 and 3, there was no significant difference in PI, BOP, and PD at 3 months' (P > 0.05) and 6-months' (P > 0.05) follow-up. There were no pockets with PD ≥ 4 mm at 3 and 6 months' follow-up in groups 2 and 3. There was no difference in the numbers of MT and none of the individuals exhibited clinical AL in all groups.

CONCLUSION

Following FMUS, gingival inflammation is worse in CS compared with individuals vaping E-cigs and NS.

CLINICAL RELEVANCE

Periodontal inflammatory parameters are worse in cigarette-smokers than individuals vaping electronic cigarettes and never-smokers following FMUS. However, these findings should be interpreted with extreme caution as a number of factors may have influenced the present results.

The effect of periodontal therapy on oxidative stress biomarkers: A systematic review

AIM

To systematically review the literature about the effect of periodontal treatment on oxidative stress (OxS) biomarkers.

MATERIAL AND METHODS

Three databases (PubMed, EMBASE, and Scopus) were searched up to February 2018. Clinical trials with a follow-up of at least 6 weeks after mechanical periodontal treatment were included. Due to the high heterogeneity among the units and indices of measurements used in the studies, a meta-analysis was not performed.

RESULTS

Overall, 3,199 studies were retrieved, of which 20 were included. Four studies were randomized clinical trials (RCT), and 16 studies were non-RCTs. The most common OxS biomarkers used were 8-hydroxydeoxiguanosine (8-OHdG), total oxidant status (TOS), and total antioxidant status (TAS). After treatment, most of the studies reported a decrease in 8-OHdG concentration in the gingival crevicular fluid (GCF) and saliva. In addition, the salivary concentration of this biomarker was similar to periodontally healthy patients. Periodontal therapy was effective in reducing TOS in GCF, saliva, and serum in most studies. TAS, however, responded inconsistently to the periodontal intervention.

CONCLUSION

Periodontal therapy reduces the levels of OxS biomarkers, even to values similar to those found in periodontally healthy individuals. Additional RCTs are warranted, as the information is mainly based on nonrandomized studies.

Elevated levels of 8-OHdG and PARK7/DJ-1 in peri-implantitis mucosa

BACKGROUND

Reactive oxygen species contribute to periodontal tissue homeostasis under control of anti-oxidative responses. Disruption in this balance induces severe inflammation and extended tissue degradation.

PURPOSE

Aim of this study was to identify the expression levels of nuclear factor, erythroid 2 like 2 (NFE2L2/NRF2), Parkinsonism associated deglycase (PARK7/DJ-1), kelch-like ECH associated protein 1 (KEAP1), and 8-hydroxy-deoxyguanosine (8-OHdG) in peri-implant mucosal tissues affected by peri-implantitis, and to compare the levels to those of periodontally diseased and healthy tissue samples.

METHODS

Tissue biopsies were collected from systemically healthy, non-smoking 12 peri-implantitis patients, 13 periodontitis patients, and 13 periodontally healthy controls. Expression levels of NFE2L2/NRF2, PARK7/DJ-1, KEAP1, and 8-OHdG in tissue samples were analyzed immunohistochemically. Statistical analysis was performed by one-way ANOVA with Tukey's HSD test.

RESULTS

Inflammatory cell infiltration in the connective tissue and loss of architecture in the spinous layer of the epithelium were prominent in peri-implantitis. Proportions of 8-OHdG and PARK7/DJ-1 expressing cells were elevated in both peri-implantitis (P = .025 for 8-OHdG and P = .014 for PARK7/DJ-1) and periodontitis (P = .038 for 8-OHdG and P = .012 for PARK7/DJ-1) groups in comparison with controls. Staining intensities of 8-OHdG and PARK7/DJ-1 were higher in the periodontitis and peri-implantitis groups than in the control (P < .01) groups. There was no difference in the expression levels of NFE2L2/NRF2 between the groups. KEAP1 was not observed in any tissue sample.

CONCLUSIONS

Peri-implantitis is characterized by severe inflammation and architectural changes in the epithelium and connective tissue. The expressions of 8-OHdG and PARK7/DJ-1 are elevated in both peri-implantitis and periodontitis.

The evaluation of salivary oxidative stress in patients with familial Mediterranean fever and chronic periodontitis

BACKGROUND

Familial Mediterranean fever (FMF) is an inherent autoinflammatory disease and have a high prevalence in Mediterranean countries. The aim of this study was to evaluate salivary levels of oxidative stress parameters in patients with FMF and chronic periodontitis.

METHODS

The study population consists of 81 patients with FMF and 85 systemically healthy controls. The test and control groups were classified as chronic periodontitis and periodontally healthy [FMF-periodontitis (n = 37); FMF-periodontally healthy (n = 44); systemically healthy-periodontitis (n = 37); systemically and periodontally healthy (n = 48]. Total salivary samples were collected. Clinical periodontal parameters including plaque index, gingival index (GI), probing depth (PD), the percentage of bleeding on probing (BOP%), and clinical attachment level (CAL), were measured. Salivary total antioxidant status (TAS), total oxidant status (TOS), 8-hydroxydeoxyguanosine (8-OHdG), malondialdehyde (MDA), and oxidative stress index (OSI) were evaluated.

RESULTS

The FMF-periodontitis group had significantly higher levels of 8-OHdG, MDA, and OSI than that of the FMF-periodontally healthy group. In the FMF-periodontitis group, PD, 8-OHdG, MDA, and OSI levels were significantly higher than in the systemically healthy-periodontitis group (P = 0.035, P = 0.000, P = 0.000, and P = 0.000, respectively). 8-OHdG values were significantly correlated with BOP% and GI, and TOS values were significantly correlated with PD and CAL in the FMF-periodontitis group.

CONCLUSIONS

In the presence of FMF and chronic periodontitis, there were increased salivary levels of oxidative stress. Thus, oxidative stress could be an important inflammatory mechanism in the FMF and chronic periodontitis. Further studies need to clarify the oxidative mechanisms of FMF and chronic periodontitis.

Meta-Analysis of the Use of 8-OHdG in Saliva as a Marker of Periodontal Disease

The objective was to collect the available evidence on oxidative stress marker measurements in periodontal patients, focusing specifically on 8-hydroxy-2′-deoxyguanosine (8-OHdG) as a salivary marker of periodontal disease, and to perform meta-analyses to calculate differences in concentration compared to healthy persons. A systematic search in PubMed, Cochrane Library, Embase, and Scopus identified 81 articles. Of these, 38 were duplicates. After reading the abstracts of the remaining 43, 42 were selected for full-text assessment. Finally, 17 articles were included in the qualitative synthesis. Those excluded were of low quality, did not answer the research question, or did not meet the inclusion and exclusion criteria. Of the 17 in the qualitative synthesis, 9 were included in the meta-analysis. The 9 studies in the meta-analysis were combined in a random effects model. Their heterogeneity was high (Q = 3982.02, p < 0.001, I² = 99.8%). The difference in mean 8-OHdG concentration in saliva between periodontal and healthy subjects was estimated at 2.11 ng/ml (95% CI 1.23–2.98). The different saliva collection methods (stimulated/unstimulated) did not explain the heterogeneity. The 8-OHdG levels in saliva of periodontal patients were almost double to those of healthy patients: 8-OHdG is clearly a powerful periodontal disease marker.

Oxidative Stress and Antioxidant System in Periodontitis

Periodontitis is a common inflammatory disease, which is initiated by bacterial infection and subsequently progressed by aberrant host response. It can result in the destruction of teeth supporting tissues and have an influence on systemic health. When periodontitis occurs, reactive oxygen species, which are overproduced mostly by hyperactive neutrophils, could not be balanced by antioxidant defense system and cause tissues damage. This is characterized by increased metabolites of lipid peroxidation, DNA damage and protein damage. Local and systemic activities of antioxidants can also be influenced by periodontitis. Total antioxidant capacity, total oxidant status and oxidative stress index have been used to evaluate the oxidative stress associated with periodontitis. Studies have confirmed that inflammatory response in periodontitis is associated with an increased local and systemic oxidative stress and compromised antioxidant capacity. Our review focuses on increased oxidative stress in periodontal disease, specifically, on the relationship between the local and systemic biomarkers of oxidative stress and periodontitis and their association with the pathogenesis of periodontitis. Also, the relationship between periodontitis and systemic inflammation, and the effects of periodontal therapy on oxidative stress parameters will be discussed.

The Role of Reactive Oxygen Species and Autophagy in Periodontitis and Their Potential Linkage

Periodontitis is a chronic inflammatory disease that causes damage to periodontal tissues, which include the gingiva, periodontal ligament, and alveolar bone. The major cause of periodontal tissue destruction is an inappropriate host response to microorganisms and their products. Specifically, a homeostatic imbalance between reactive oxygen species (ROS) and antioxidant defense systems has been implicated in the pathogenesis of periodontitis. Elevated levels of ROS acting as intracellular signal transducers result in autophagy, which plays a dual role in periodontitis by promoting cell death or blocking apoptosis in infected cells. Autophagy can also regulate ROS generation and scavenging. Investigations are ongoing to elucidate the crosstalk mechanisms between ROS and autophagy. Here, we review the physiological and pathological roles of ROS and autophagy in periodontal tissues. The redox-sensitive pathways related to autophagy, such as mTORC1, Beclin 1, and the Atg12-Atg5 complex, are explored in depth to provide a comprehensive overview of the crosstalk between ROS and autophagy. Based on the current evidence, we suggest that a potential linkage between ROS and autophagy is involved in the pathogenesis of periodontitis.

Estimation of tissue and crevicular fluid oxidative stress marker in premenopausal, perimenopausal and postmenopausal women with chronic periodontitis

OBJECTIVES

The aim of this study was to estimate tissue and gingival crevicular fluid (GCF) levels of the oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) in premenopausal, perimenopausal and postmenopausal women with chronic periodontitis.

BACKGROUND

Oxidative stress has been implicated in the etiopathogenesis of periodontitis and menopause induces oxidative stress.

MATERIALS AND METHODS

According to Stages of Reproductive Aging Workshop (STRAW) criteria, women diagnosed with periodontitis were subdivided into three groups of 31 participants each 1. Premenopausal 2. Perimenopausal and 3. Postmenopausal. GCF and gingival tissue samples were collected from sites with maximum probing depth. Tissue DNA was extracted from the gingival sample and 8-OHdG in the extracted DNA, and GCF samples were measured using ELISA.

RESULTS

There was a highly significant difference in the overall GCF 8-OHdG levels among the three groups with the pairwise difference being highly significant between the premenopausal-postmenopausal groups and perimenopausal-postmenopausal groups. However, no overall significant differences in tissue 8-OHdG levels were found among the three groups. Pairwise, highly significant differences were found between the premenopausal-postmenopausal groups and perimenopausal-postmenopausal groups for tissue 8-OHdG levels. No significant correlations were found between various measure of periodontal disease and GCF/tissue 8-OHdG levels among all the groups.

CONCLUSION

Premenopausal-postmenopausal and perimenopausal-postmenopausal transition resulted in significant increase in tissue and GCF 8-OHdG levels. However, no association was found between stages of reproductive ageing and tissue levels of 8-OHdG.

Effect of scaling and root planing on levels of 8-hydroxydeoxyguanosine in gingival crevicular fluid of chronic periodontitis patients with and without Type II diabetes mellitus

Context:

Chronic periodontitis (CP) and diabetes mellitus are associated with increased oxidative damage to DNA with formation of 8-hydroxydeoxyguanosine (8-OHdG). The aim of this study was to evaluate the change in gingival crevicular fluid (GCF) levels of 8-OHdG and glycosylated hemoglobin (HbA1c) by 3 months after scaling and root planing (SRP), in CP patients with and without Type II diabetes mellitus.

Settings and Design:

Sixteen patients with CP, 16 patients with CP and Type II diabetes mellitus (CP-D), and 16 systemically healthy individuals with clinically healthy periodontium who served as controls were included in the study.

Materials and Methods:

The clinical parameters (plaque index [PI], probing depth [PD], clinical attachment level [CAL], and bleeding on probing [BOP%]), HbA1c levels, and GCF 8-OHdG levels were measured at baseline. All the patients except controls were treated with SRP followed by evaluation of the above-mentioned clinical and biochemical parameters after 3 months.

Statistical Analysis Used:

Statistical analysis was performed using paired t-test, independent t-test, and Mann–Whitney U-test.

Results:

After SRP, CP-D group showed a greater reduction in PI, PD, BOP%, and greater gain in CAL when compared to CP patients (P < 0.05). Levels of 8-OHdG and HbA1c in CP-D patients also showed a greater reduction, 3 months after SRP when compared to CP patients (P < 0.05).

Conclusions:

GCF 8-OHdG levels, HbA1c levels, and clinical parameters were reduced significantly in CP and CP-D patients, with maximum reduction achieved in CP-D patients 3 months after SRP.

Salivary oxidative stress biomarkers in chronic periodontitis and acute coronary syndrome

OBJECTIVES

The study aimed at assessing oxidative stress (OS) biomarker levels in the saliva of patients with chronic periodontitis (CP) and acute coronary syndrome (ACS) and establishing their correlation to periodontal parameters and markers for cardiovascular events.

MATERIALS AND METHODS

The present study enrolled 24 patients with ACS and CP (the ACSCP group), 24 patients with ACS only (the ACS group), 24 patients with CP only (the CP group), and 24 healthy controls. Plaque index (PI), gingival index, bleeding on probing, probing pocket depth (PPD), and clinical attachment loss were recorded. Markers for cardiovascular events included serum high sensitivity C-reactive protein (hsCRP) and plasma fibrinogen. 8-Hydroxydeoxyguanosine (8-OHdG), protein carbonyl (PC), malondialdehyde (MDA), and total antioxidant capacity (TAOC) were used as OS biomarkers.

RESULTS

Salivary 8-OHdG, MDA, and PC levels were significantly higher in the ACSCP, ACS, and CP groups than in healthy controls (p < 0.05). There were significant correlations between salivary PC levels and PI or PPD (p < 0.05) as well as between salivary 8-OHdG levels and all periodontal parameters (p < 0.05). TAOC levels in saliva were correlated to both serum hsCRP and plasma fibrinogen (p < 0.05). Salivary MDA levels were correlated to all periodontal parameters and biomarkers for cardiovascular events (p < 0.05).

CONCLUSIONS

Salivary OS biomarker levels were higher in diseased groups compared to control. They also correlated to clinical periodontal parameters and markers for cardiovascular events in ACS patients, with or without CP.

CLINICAL RELEVANCE

Salivary OS biomarkers could potentially serve as diagnostic tools for cardiovascular and/or periodontal diseases.

Identification of Gingival Crevicular Fluid Sampling, Analytical Methods, and Oral Biomarkers for the Diagnosis and Monitoring of Periodontal Diseases: A Systematic Review

Background. Several studies in the last decades have focused on finding a precise method for the diagnosis of periodontal disease in its early stages. Aim. To evaluate from current scientific literature the most common and precise method for gingival crevicular fluid (GCF) sample collection, biomarker analytical methods, and the variability of biomarker quantification, even when using the same analytical technique. Methodology. An electronic search was conducted on in vivo studies that presented clinical data on techniques used for GCF collection and biomarker analysis. Results. The results showed that 71.1%, 24.7%, and 4.1% of the studies used absorption, microcapillary, and washing techniques, respectively, in their gingival crevicular fluid collection. 73.1% of the researchers analyzed their samples by using enzyme-linked immunosorbent assay (ELISA). 22.6%, 19.5%, and 18.5% of the researchers included interleukin-1 beta (IL-1β), matrix metalloproteinase-8 (MMP-8), and tumor necrosis factor-alpha (TNF-α), respectively, in their studies as biomarkers for periodontal disease. Conclusion. IL-1β can be considered among the most common biomarkers that give precise results and can be used as an indicator of periodontal disease progression. Furthermore, paper strips are the most convenient and accurate method for gingival crevicular fluid collection, while enzyme-linked immunosorbent assay can be considered the most conventional method for the diagnosis of biofluids.

Saliva diagnostics - Current views and directions

In this review, we provide an update on the current and future applications of saliva for diagnostic purposes. There are many advantages of using saliva as a biofluid. Its collection is fast, easy, inexpensive, and non-invasive. In addition, saliva, as a "mirror of the body," can reflect the physiological and pathological state of the body. Therefore, it serves as a diagnostic and monitoring tool in many fields of science such as medicine, dentistry, and pharmacotherapy. Introduced in 2008, the term "Salivaomics" aimed to highlight the rapid development of knowledge about various "omics" constituents of saliva, including: proteome, transcriptome, micro-RNA, metabolome, and microbiome. In the last few years, researchers have developed new technologies and validated a wide range of salivary biomarkers that will soon make the use of saliva a clinical reality. However, a great need still exists for convenient and accurate point-of-care devices that can serve as a non-invasive diagnostic tool. In addition, there is an urgent need to decipher the scientific rationale and mechanisms that convey systemic diseases to saliva. Another promising technology called liquid biopsy enables detection of circulating tumor cells (CTCs) and fragments of tumor DNA in saliva, thus enabling non-invasive early detection of various cancers. The newly developed technology-electric field-induced release and measurement (EFIRM) provides near perfect detection of actionable mutations in lung cancer patients. These recent advances widened the salivary diagnostic approach from the oral cavity to the whole physiological system, and thus point towards a promising future of salivary diagnostics for personalized individual medicine applications including clinical decisions and post-treatment outcome predictions. Impact statement The purpose of this mini-review is to make an update about the present and future applications of saliva as a diagnostic biofluid in many fields of science such as dentistry, medicine and pharmacotherapy. Using saliva as a fluid for diagnostic purposes would be a huge breakthrough for both patients and healthcare providers since saliva collection is easy, non-invasive and inexpensive. We will go through the current main diagnostic applications of saliva, and provide a highlight on the emerging, newly developing technologies and tools for cancer screening, detection and monitoring.

Impact of non-surgical periodontal therapy on saliva and serum levels of markers of oxidative stress

OBJECTIVE

The purpose of this study was to determine the effect of non-surgical periodontal treatment on markers of oxidative stress in saliva and serum in patients with chronic periodontitis.

MATERIALS AND METHODS

In total, 25 patients, who were diagnosed with generalized chronic periodontitis (11 females and 14 males), and 26 systemically and periodontally healthy individuals (15 females and 11 males) were included. The plaque index (PI), gingival index (GI), probing pocket depth (PPD), attachment loss (AL), gingival recession (GR), and bleeding on probing (BOP) were recorded at baseline and 6 weeks later. Malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and 4-hydroxy-2-nonenal (4-HNE) were assessed in saliva and serum samples before and after the non-surgical treatment by enzyme-linked immune sorbent assay (ELISA).

RESULTS

In the group with chronic periodontitis, all clinical parameters were significantly higher compared to the control group at baseline (p < 0.001). Periodontal treatment reduced plaque, gingival inflammation, and pocket depth significantly (p < 0.001). At baseline, salivary 8-OHdG was significantly higher in chronic periodontitis (p < 0.001) and reduced significantly subsequent to the periodontal treatment (p < 0.001). Salivary MDA and serum 4-HNE were significantly higher in the patients with periodontitis compared to the control group (p < 0.001). Periodontal treatment did not significantly change the levels of 4-HNE and salivary MDA (p = 0.503, p = 0.093).

CONCLUSIONS

Salivary 8-OHdG and MDA may be associated with local impact of periodontal disease, while 4-HNE may be associated with systemic impact of chronic periodontitis.

CLINICAL RELEVANCE

Clinical intervention in periodontitis may be beneficial for periodontitis patients' systemic oxidative stress control, and using lipidic agents for the use of anti-inflammatory/pro-resolving processes for blocking the actions of arachidonic acid cascade can enable some late therapeutic strategies in order to lead oxidative stress-induced inflammation.

Nuclear Factor Erythroid 2-Related Factor 2 Down-Regulation in Oral Neutrophils Is Associated with Periodontal Oxidative Damage and Severe Chronic Periodontitis

The balance between reactive oxygen species and antioxidants plays an important role in periodontal health. We previously demonstrated that high reactive oxygen species production by oral polymorphonuclear neutrophils (oPMNs) in chronic periodontitis (CP) refractory to conventional therapy is associated with severe destruction of periodontium. Herein, we show that inhibition of antioxidant production through down-regulation of nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in oPMN, despite enhanced recruitment in the oral cavity, is associated with severe CP. Twenty-four genes in the Nrf2-mediated oxidative stress response pathway were down-regulated in PMNs of diseased patients. Downstream of Nrf2, levels of oPMN superoxide dismutase 1 and catalase were decreased in severe CP, despite increased recruitment. Nrf2(-/-) mice had more severe loss of periodontium in response to periodontitis-inducing subgingival ligatures compared with wild-types. Levels of 8-hydroxy-deoxyguanosine were increased in periodontal lesions of Nrf2(-/-) mice, indicating high oxidative damage. We report, for the first time, Nrf2 pathway down-regulation in oPMNs of patients with severe CP. PMNs of CP patients may be primed for low antioxidant response in the context of high recruitment in the oral cavity, resulting in increased oxidative tissue damage.

Association between periodontitis and salivary 8-hydroxydeoxyguanosine among Korean rural adults

OBJECTIVES

This study aimed to evaluate the association between salivary 8-hydroxydeoxyguanosine (8-OHdG) and periodontitis among community-dwelling Korean adults.

METHODS

A total of 211 adults (80 men and 131 women) were cross-sectionally surveyed from the Sunchang Longevity Cohort. Periodontitis was defined as having at least 30% of teeth with proximal attachment loss ≥5 mm. The salivary 8-OHdG level was categorized into tertiles: low (<0.916 ng/ml), medium (0.916 to <2.675 ng/ml) and high (≥2.675 ng/ml). Sociodemographic, habitual and systemic health-related factors were controlled for. Logistic regression analysis was performed for the outcome of severe periodontitis. Analysis of covariance in general linear model was performed for the outcome of 8-OHdG.

RESULTS

The high 8-OHdG level showed a significant association with periodontitis. The odds ratio (95% confidence interval) was 2.40 (1.05-5.51), and it was highlighted by adding the interaction term with drinking and smoking. The adjusted mean log-transformed value of 8-OHdG was significantly higher in the severe periodontitis group (1.40 ng/ml) than in the control group (1.02 ng/ml) (ancova, P = 0.028).

CONCLUSIONS

8-OHdG was associated with periodontitis. Thus, salivary 8-OHdG could be a useful marker for periodontitis.

The effect of initial periodontal treatment on plasma, gingival crevicular fluid and salivary levels of 8-hydroxy-deoxyguanosine in obesity

OBJECTIVE

Recent studies have shown adverse effects on the periodontium from the increased production of reactive oxygen species (ROS) in obesity. The purpose of this study was to investigate the effects of obesity on 8-hydroxy-deoxyguanosine (8-OHdG) levels in the bodily fluids of patients with and without periodontal disease and to evaluate changes after initial periodontal treatment.

DESIGN

Forty-five obese individuals and 45 normal-weight individuals were included in this study. Obese and normal-weight groups were classified into three sub-groups: chronic periodontitis (CP), gingivitis (G) and periodontally healthy controls (CTRL). Gingival crevicular fluid (GCF), plasma, saliva samples and clinical measurements were obtained at baseline and a month after initial periodontal treatment. Levels of 8-OHdG were analysed by ELISA.

RESULTS

While plasma 8-OHdG levels were significantly higher at baseline in the obese patients with periodontal disease than in the normal-weight individuals (P<0.05), no significant differences in GCF and saliva 8-OHdG levels were found (P ˃ 0.05). GCF and salivary 8-OHdG levels in obese patients with G and CP were significantly higher than in CTRL groups at baseline (P<0.05). After treatment, 8-OHdG levels were decreased in all groups with periodontal disease (P<0.01). Statistically significant positive correlations were observed between GCF 8-OHdG levels and GI in all the groups (P<0.001).

CONCLUSIONS

The significant increase of plasma 8-OHdG levels in obese patients did not correlate with saliva and GCF 8-OHdG levels when compared to normal-weight individuals. Periodontal treatment had a positive effect on the periodontal parameters and 8-OHdG levels of both obese and normal-weight individuals.

Salivary markers of oxidative stress in oral diseases

Saliva is an interesting alternative diagnostic body fluid with several specific advantages over blood. These include non-invasive and easy collection and related possibility to do repeated sampling. One of the obstacles that hinders the wider use of saliva for diagnosis and monitoring of systemic diseases is its composition, which is affected by local oral status. However, this issue makes saliva very interesting for clinical biochemistry of oral diseases. Periodontitis, caries, oral precancerosis, and other local oral pathologies are associated with oxidative stress. Several markers of lipid peroxidation, protein oxidation and DNA damage induced by reactive oxygen species can be measured in saliva. Clinical studies have shown an association with oral pathologies at least for some of the established salivary markers of oxidative stress. This association is currently limited to the population level and none of the widely used markers can be applied for individual diagnostics. Oxidative stress seems to be of local oral origin, but it is currently unclear whether it is caused by an overproduction of reactive oxygen species due to inflammation or by the lack of antioxidants. Interventional studies, both, in experimental animals as well as humans indicate that antioxidant treatment could prevent or slow-down the progress of periodontitis. This makes the potential clinical use of salivary markers of oxidative stress even more attractive. This review summarizes basic information on the most commonly used salivary markers of oxidative damage, antioxidant status, and carbonyl stress and the studies analyzing these markers in patients with caries or periodontitis.

Salivary metabolomics in the diagnosis of oral cancer and periodontal diseases

Metabolomics is a systemic study of metabolites, which are small molecules generated by the process of metabolism. The metabolic profile of saliva can provide an early outlook of the changes associated with a wide range of diseases, including oral cancer and periodontal diseases. It is possible to measure levels of disease-specific metabolites using different methods as presented in this study. However, many challenges exist including incomplete understanding of the complicated metabolic pathways of different oral diseases. The review concludes with the discussion on future perspectives of salivary metabolomics from a clinician point of view. Salivary metabolomics may afford a new research avenue to identify local and systemic disorders but also to aid in the design and modification of therapies. A MEDLINE search using keywords "salivary metabolomics" returned 23 results in total, of which seven were omitted for being reviews or letters to the editor. The rest of the articles were used for preparation of the review, 13 of these were published in the last 5 years.

Prognostic Value of 8-Hydroxy-2'-Deoxyguanosine and Human Neutrophil Elastase/α1-Proteinase Inhibitor Complex as Salivary Biomarkers of Oxidative Stress in Chronic Periodontitis

BACKGROUND

8-Hydroxy-2'-deoxyguanosine (8-OHdG) and human neutrophil elastase/α1-proteinase inhibitor (HNE/α1-PI) complex have been regarded as reliable biomarkers of oxidative stress in inflammatory conditions. This study investigates whether the salivary levels of these two analytes may be linked with periodontal health status.

METHODS

One hundred ten patients with chronic periodontitis (CP) and 50 healthy controls were selected. Periodontal status was assessed by criteria based on probing depth, clinical attachment level, and extent and severity of periodontal breakdown. 8-OHdG and HNE/α1-PI salivary levels were analyzed by enzyme-linked immunosorbent assay. The association of these analytes with CP was analyzed individually and adjusted for confounding factors using a multivariate binary logistic regression model.

RESULTS

Significantly higher levels of both markers were detected in the CP group in comparison to controls. Weak-to-moderate positive significant correlations between salivary biomarkers and clinical parameters were observed. After binary logistic regression analysis, salivary levels of 8-OHdG >17.35 ng/mL and HNE/α1-PI complex >158.28 ng/mL were independently associated with disease status. Interaction effects among candidate prognostic variables were also noted.

CONCLUSIONS

Increased salivary levels of 8-OHdG and HNE/α1-PI complex may be strong, independent prognostic indicators of the amount and extent of oxidative stress-induced periodontal breakdown. In addition, unstimulated whole saliva samples might reflect a synergistic biologic interactive effect of HNE/α1-PI associated with the aging and smoking cumulative characteristics of periodontal damage.

Oxidative stress markers in saliva and periodontal disease status: modulation during pregnancy and postpartum

BACKGROUND

Periodontal diseases may affect local and systemic inflammation, and reactive oxygen species (ROS) levels. This systemic health burden could compromise the outcome of pregnancy in expectant mothers. The aim of the present study was to evaluate oxidative stress markers, including glutathione peroxidase (GPx), thiobarbituric acid-reactive substances (TBARS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total bacterial loads in the saliva of pregnant and postpartum women, and to investigate their association with periodontal disease severity.

METHODS

A total of 187 women were originally recruited for this case-control study, assigned to the following groups a) pregnant group, b) postpartum group: the pregnant group re-evaluated 6 months after giving birth, c) control group: systemically healthy and non-pregnant women. The levels of the studied oxidative stress markers in saliva were measured by commercially available kits.

RESULTS

The levels of salivary 8-OHdG were significantly elevated in the pregnant, compared with the control group. Although salivary 8-OHdG levels slightly decreased after giving birth (postpartum group), the difference did not reach significance. In contrast, the activity of antioxidant enzyme GPx in saliva was significantly lower in the pregnant than the control group. Although no differences in lipid peroxidation (represented by TBARS) were observed between the pregnant and control groups, after giving birth TBARS levels were significantly lowered. Only in the postpartum and control groups did clinical measurements of periodontal disease severity correlate with oxidative stress markers. Interestingly, there were no such correlations with TBARS in the pregnant and postpartum groups.

CONCLUSIONS

The present study shows changes in the oxidant/antioxidant balance in saliva during pregnancy and after birth, which may be affected by periodontal health status in the latter case. Whether this is associated with adverse pregnancy outcomes, or not, remains to be elucidated. Early identification of ROS markers in saliva may be of clinical value in the periodontal management of pregnant women.

High sensitivity detection of salivary 8-hydroxy deoxyguanosine levels in patients with chronic periodontitis

BACKGROUND

Inflammation is associated with hydroxyl radical damage to DNA as a result of oxidative stress. 8-Hydroxy deoxyguanosine (8-OHdG) is a marker of this process and its levels in saliva could be linked to the severity of periodontal inflammation. The aim of this study was to test the sensitivity of liquid chromatography with tandem mass spectrometry (LC-MS/MS) in comparison to enzyme-linked immune sorbent assay (ELISA) for the detection of 8-OHdG in saliva in patients with chronic periodontitis before and after periodontal treatment.

METHODS

Saliva samples were collected from 23 patients (eight females and 15 males; 46.1 ± 5.1 years of age) with generalized chronic periodontitis and 25 (15 females and 10 males; 44.9 ± 6.8 years of age) periodontally healthy individuals. Patients received initial periodontal treatment consisting of scaling and root planing and were evaluated at baseline and after 6 wk of completion of non-surgical therapy. Salivary 8-OHdG levels were measured using ELISA and LC-MS/MS before and after the treatment. Clinically, plaque index, gingival index, clinical attachment level, bleeding on probing, gingival recession and probing pocket depth were measured at baseline and after 6 wk.

RESULTS

Salivary levels of 8-OHdG decreased significantly after the non-surgical periodontal treatment (p < 0.001). Statistically significant positive correlations were observed between plaque index, gingival index, probing pocket depth, clinical attachment level, bleeding on probing values and LC-MS/MS and ELISA levels of 8-OHdG (p < 0.001).

CONCLUSION

LC-MS/MS is a reliable and sensitive method for evaluating salivary 8-OHdG levels to monitor the treatment response of periodontitis.

Evaluation of lipid peroxidation and oxidative DNA damage in patients with periodontitis and hyperlipidemia

BACKGROUND

The purpose of this study is to determine the serum levels of malondialdehyde (MDA), as a lipid peroxidation marker, and 8-hydroxydeoxyguanosine (8-OHdG), as an oxidative DNA damage marker, in patients with chronic periodontitis (CP) and hyperlipidemia.

METHODS

A total of 74 individuals were divided into four age- and sex-matched groups: 18 patients with hyperlipidemia and CP (HLp), 18 periodontally healthy patients with hyperlipidemia (HLh), 19 systemically healthy individuals with CP (Cp), and 19 systemically and periodontally healthy controls (Ch). Clinical periodontal parameters were measured, and serum lipids, MDA, and 8-OHdG levels were assessed in blood samples.

RESULTS

8-OHdG, MDA, probing depth, clinical attachment level, and percentage of sites bleeding on probing (BOP) were significantly higher in the HLp group than the Cp group. In the hyperlipidemic group, BOP was significantly correlated with total cholesterol, the ratio of total cholesterol to high-density lipoprotein cholesterol, and 8-OHdG levels. A significant correlation between 8-OHdG and MDA was also observed in the hyperlipidemia group.

CONCLUSIONS

In this study, serum MDA and 8-OHdG were found to be highest in the HLp group. The increased levels of MDA and 8-OHdG in HLp patients may be a result of a harmful oxidative status in association with hyperlipidemia and periodontitis.

Effect of initial periodontal therapy on oxidative stress markers in gingival crevicular fluid, saliva, and serum in smokers and non-smokers with chronic periodontitis

BACKGROUND

The aim of this case-control study with an intervention arm is to determine the effect of initial periodontal treatment on oxidative stress biomarkers in smokers and non-smokers with chronic periodontitis (CP).

METHODS

The study included 47 patients with CP (24 smokers [S+P+] and 23 non-smokers [S-P+]) and 46 periodontally healthy individuals (23 smokers [S+P-] and 23 non-smokers [S-P-]) for a total of 93 participants. Gingival crevicular fluid (GCF), serum, and saliva samples were obtained and clinical periodontal measurements were recorded at baseline and at the first and third months after periodontal therapy. 8-hydroxydeoxyguanosine (OHdG) and 4-hydroxynonenal (HNE) and enzyme activity of glutathione peroxidase (GSH-Px) were analyzed with enzyme-linked immunosorbent assay.

RESULTS

The level of 8-OHdD in GCF was found to be significantly higher in both periodontitis groups compared with both periodontally healthy groups. 8-OHdG and GSH-Px in saliva in both periodontitis groups were significantly increased compared with the S-P- group. In the S+P+ group, 4-HNE in GCF was found to be significantly higher than in periodontally healthy participants. After initial periodontal treatment, the levels of 8-OHdG in GCF and saliva were significantly decreased in both periodontitis groups.

CONCLUSION

Initial periodontal therapy may be helpful for diminishing oxidative stress in periodontitis.

Locally delivered antioxidant gel as an adjunct to nonsurgical therapy improves measures of oxidative stress and periodontal disease

Purpose

The present study has two aims; firstly, it attempts to verify the presence of oxidative stress by estimating the reactive oxygen species (ROS) levels in periodontal pockets ≥5 mm as compared to controls. The second aim is to evaluate the effect of lycopene as a locally delivered antioxidant gel on periodontal health and on the gingival crevicular fluid (GCF) levels of 8-hydroxydeoxyguanosine (8-OHdG), a marker of oxidative injury.

Methods

Thirty-one subjects participated in this study. In the pretreatment phase, the ROS levels in pockets ≥5 mm were measured by flow cytometry. Three sites in each subject were randomly assigned into each of the following experimental groups: sham group, only scaling and root planing (SRP) was done; placebo group, local delivery of placebo gel after SRP; and lycopene group, local delivery of lycopene gel after SRP. Clinical parameters included recording site-specific measures of GCF 8-OHdG, plaque, gingivitis, probing depth, and clinical attachment level.

Results

The gel, when delivered to the sites with oxidative stress, was effective in increasing clinical attachment and in reducing gingival inflammation, probing depth, and 8-OHdG levels as compared to the placebo and sham sites.

Conclusions

From this trial conducted over a period of 6 months, it was found that locally delivered lycopene seems to be effective in reducing the measures of oxidative stress and periodontal disease.