Nitric oxide synthesis and severity of human periodontal disease

Salivary and serum nitric oxide synthase, macrophage inflammatory protein 1 alpha and macrophage migration inhibitory factor levels in periodontal disease

Objective

Periodontal disease is multifactorial inflammatory disease involving both gingivitis and periodontitis. Inducible nitric oxide synthase (iNOS), macrophage inflammatory protein 1 alpha (MIP-1α) and macrophage migration inhibitory factor (MIF) are mediators contributing to the progression of periodontal diseases with distinct functions. The aim of this study is to evaluate the local and systemic iNOS, MIP-1α and MIF concentrations in patients having periodontal disease with different severities.

Design

The study was conducted on 88 individuals equally divided into four groups; 1) Periodontally Healthy 2) Gingivitis 3) Stage I-II Periodontitis 4) Stage III-IV Periodontitis. Saliva and serum samples were obtained from each individual and then periodontal examinations were performed. Plaque and bleeding on probing indexes, probing depths and clinical attachment levels were measured on each tooth to determine the periodontal status. Concentrations of iNOS, MIP-1α and MIF were measured with enzyme-linked immunosorbent assay.

Results

Patients with stage I-II and stage III-IV periodontitis had more iNOS levels than periodontally healthy people in serum and saliva (p ≤ 0,001 for serum; p < 0,05 for saliva). Stage III-IV periodontitis group had significantly more serum-iNOS levels than that in gingivitis group (p = 0,005). When compared with periodontally healthy individuals, MIP-1α levels in stage III-IV periodontitis patients were measured significantly more in saliva; (p = 0,016) but less in serum (p = 0,006) samples. More serum-MIF concentrations were observed in stage I-II periodontitis groups than that in periodontally healthy individuals (p < 0,05).

Conclusion

Increased salivary and serum iNOS and serum-MIF levels in different stages of periodontitis suggest that these molecules might be involved in periodontal disease pathogenesis. Also, oral microenvironment may stimulate the enhanced MIP-1α concentration in advanced periodontitis cases.

The Link between Periodontal Disease and Asthma: How Do These Two Diseases Affect Each Other?

A growing body of evidence suggests that the effects of poor oral hygiene extend beyond the oral cavity and are associated with a variety of systemic diseases, including asthma. Asthma, which results in symptoms of cough, wheezing, and dyspnoea, and is characterized by airflow limitation with variability and (partial or complete) reversibility, is amongst the most prevalent respiratory diseases with approximately 262 million patients worldwide, and its prevalence and disease burden is on the increase. While asthma can occur at a young age, it can also develop later in life and affects a variety of age groups. Both of these diseases have a chronic course, and various researchers have suggested a link between the two. In this article, we aim to provide a literature review focusing on the association between the two diseases. The results demonstrate that medications (primarily, inhaler medicine), hypoxia induced by asthma, and the breathing behaviour of patients potentially trigger periodontal disease. In contrast, oral periodontopathogenic microorganisms and the inflammatory mediators produced by them may be involved in the onset and/or exacerbation of asthma. Common contributing factors, such as smoking, gastro-oesophageal reflux, and type-2 inflammation, should also be considered when evaluating the relationship between the two diseases.

Optimizing the Fermentation Conditions of Cudrania tricuspidata Fruit Using Bacillus amyloliquefaciens for Anti-Inflammatory Activity and GC-MS-Based Volatile Component Characteristics

The aim of this study is to optimize the performance conditions used for maximum anti-inflammatory activity and to clarify in vitroanti-inflammatory properties of fermented C. tricuspidata fruit. Based on the single-factor experiment and Box-Behnken design, the optimized fermentation conditions of C. tricuspidata fruit for maximum anti-inflammatory activity were 3.8 d fermentation period, 8.4% (v/w) inoculation concentration, and 29.2°C fermentation temperature. Under optimal conditions, anti-inflammatory activity-based nitric oxide of fermented C. tricuspidata fruit reached 93.9%. Moreover, this study provides a theoretical basis and experimental data containing β-hexosaminidase and reactive oxygen species for the medical use and industrialization of C. tricuspidata fruit fermentation. Interestingly, the results of GC-MS analysis confirmed that fermented C. tricuspidata fruits detect volatile components different from unfermented C. tricuspidata fruits. We suggested that this volatile component may have been involved in the anti-inflammatory reaction, but scientific verification of this is needed later. Therefore, an in-depth study of volatile components detected from fermented C. tricuspidata fruits will need to be conducted later.

The Impact of COVID-19 on the Oral Bacterial Flora in Patients Wearing Complete Dentures and on the Level of Exhaled Nitric Oxide as a Marker of Inflammation

BACKGROUND

Exhaled nitric oxide is helpful in the diagnosis of the inflammation process. The study aimed to analyze the impact of the COVID-19 disease on the oral bacterial flora of patients using complete dentures with a diagnostic device that measures the level of NO in exhaled air.

MATERIALS AND METHODS

The study included patients using upper and lower acrylic complete dentures. All patients participating in the study were vaccinated against COVID-19. The patients were divided into two groups. A dental examination was conducted in each group. The NO concentration was measured using the Vivatmo Pro device. An oral microbiological examination was performed by taking a swab from the bottom of the mouth.

RESULTS

There were no statistically significant differences in the distribution of NO in relation to the number of bacteria from isolated families in the study and control groups and no statistically significant correlations between the level of NO and the number of bacteria from all families in the control and study group. Significantly higher NO values were present in the vaccinated and COVID-19-positive history population compared to the vaccinated and with no COVID-19 history population (patients with no clinical symptoms of infection or unaware they had COVID-19).

CONCLUSIONS

There are statistically significant differences in NO distribution in the considered populations: vaccinated and sick, and vaccinated and with a negative history of COVID-19. The measurement of NO in exhaled air can be a complementary, non-invasive diagnostic and inflammation monitoring method.

Oral inflammatory load predicts vascular function in a young adult population: a pilot study

Background

The periodontium is a highly vascularized area of the mouth, and periodontitis initiates negative functional and structural changes in the vasculature. However, mild oral inflammation, including levels experienced by many apparently healthy individuals, has an unclear impact on cardiovascular function. The purpose of this pilot study is to investigate the effects of objectively measured whole mouth oral inflammatory load (OIL) on vascular function in apparently healthy individuals.

Methods

In this cross-sectional and correlational analysis, we recruited 28 young (18-30 years) and systemically healthy participants (16 male, 12 female). Using oral neutrophil counts, a validated measure for OIL, we collected participant's mouth rinse samples and quantified OIL. Blood pressure, arterial stiffness (pulse-wave velocity) and endothelial function (brachial artery flow-mediated dilation) were also measured.

Results

Only oral neutrophil count significantly predicted flow-mediated dilation % (p = 0.04; R2 = 0.16, β = - 1.05) and those with OIL levels associated with >2.5 × 105 neutrophil counts (n = 8) had a lower flow-mediated dilation % (6.0 ± 2.3%) than those with counts associated with gingival health with less than 2.5 × 105 neutrophil counts (10.0 ± 5.2%, p = 0.05). There were no significant predictors for arterial stiffness.

Conclusion

We found that OIL was a predictor of reduced flow-mediated dilation. An impairment in flow-mediated dilation is an indicator of future possible risk of cardiovascular disease-one of the leading causes of death in North America. Therefore, this study provides evidence for the importance of oral health and that OIL may impact endothelial function.

Asymmetric and symmetric dimethylarginine gingival crevicular fluid levels in periodontitis

OBJECTIVE

This study aimed to evaluate the level of ADMA (asymmetric dimethylarginine), SDMA (symmetric dimethylarginine), and IL-1β (Interleukin-1β) in gingival crevicular fluid (GCF) from periodontitis patients and control subjects.

BACKGROUND

ADMA and SDMA are potentially hazardous non-proteinogenic amino acids that limit nitric oxide (NO) synthesis and have many functions in various human disorders. ADMA causes a structural change in nitric oxide synthase, while SDMA blocks arginine cell uptake. Increased plasma ADMA has been widely recognized as a "trigger" initiating impaired NO bioavailability and vascular dysfunction, which ultimately leads to oxidative stress.

METHODS

Twenty-five patients with periodontitis (P) (Stage III, Grade C, n = 25) and 20 control (C) subjects were included in the study. The IL-1β level of GCF was measured by enzyme immunoassay (ELISA) and ADMA and SDMA by liquid chromatography-mass spectrometry (LC-MS/MS).

RESULTS

Periodontitis patients had higher clinical parameters than controls (p < .001). Levels of IL-1β, ADMA and SDMA GCF were statistically significantly higher in group P than in group C (respectively; p = .003, p < .0001, p < .0001). There was no difference in the ADMA/SDMA ratio (p = .312) between the groups. There were significant positive correlations between clinical periodontal parameters and IL-1β, ADMA, and SDMA levels (p < .05). ADMA and SDMA levels were significantly correlated with IL-1β (p < .05).

CONCLUSIONS

These findings suggest that ADMA and SDMA may be involved in the pathogenesis of the periodontal disease.

Serum nitric oxide concentration in generalized chronic and aggressive periodontitis in the Mexican population is not related to the severity of the disease

Introduction: Periodontitis is an inflammatory disease that affects the supporting tissues of teeth, the effects of excess of nitric oxide, may contribute to the symptoms of periodontitis. Objective: To determine the serum nitric oxide concentration in generalized chronic and aggressive periodontitis patients and to compare it with a healthy subject group from the Mexican population. Materials and methods: A case and control study was performed. Sixty-nine individuals were recruited from the Clínica de Posgrado de Periodoncia of the Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, México. Patients with clinical features of generalized chronic periodontitis (GCP group, n=19), generalized aggressive periodontitis (GAP group, n=11), and a group of healthy subjects (HS group, n=39) were included in the study. Informed consent was obtained from each subject, and serum nitric oxide concentration was measured by an enzyme-linked immunosorbent assay. Results: Nitric oxide concentration in the study groups was greater in the GCP group (462.57 ± 16.57 μmol/L) than in the GAP group (433.84 ± 18.61 μmol/L) and the HS group (422.46 ± 12.07 μmol/L). A comparison using Student’s t-test (one-tailed) between healthy subjects and generalized chronic periodontitis showed borderline significance (p<0.04), whereas no significant differences were observed in HS and GAP groups, with a p-value of 0.64, and the GAP vs. GCP p-value was 0.33. Conclusion: The serum nitric oxide concentration observed in the present study suggests that nitric oxide plays a major role in the inflammatory process, which cannot necessarily be linked to the severity of the disease and periodontal tissue destruction.

Antimicrobial and anti-inflammatory activity of Cystatin C on human gingival fibroblast incubated with Porphyromonas gingivalis

Background

Periodontal disease is considered one of the most prevalent chronic infectious diseases, often leading to the disruption of tooth-supporting tissues, including alveolar bone, causing tooth mobility and loss. Porphyromonas gingivalis is considered the major etiological agent of this disease, having a plethora of virulence factors, including, lipopolysaccharides (LPS), hemolysins, and proteinases. Antimicrobial peptides are one of the main components of the innate immune response that inhibit the growth of P. gingivalis. The aim of this study was to analyze the antimicrobial activity of cystatin C and to assess the effect on the inflammatory and anti-inflammatory cytokines, the production of reactive oxygen species, and in the release of nitric oxide by human gingival fibroblasts incubated with P. gingivalis in the presence and absence of cystatin C.

Methods

P. gingivalis ATCC 33277 was exposed to cystatin C for 24h and co-cultured with human gingival fibroblasts (HGFs) ATCC CRL-2014. The effect of cystatin on growth of P. gingivalis and HGFs was evaluated. Pro-inflammatory (TNFα, IL-1β) and anti-inflammatory (IL-10) cytokines were determined by ELISA in the supernatants of HGFs incubated with P. gingivalis exposed to cystatin C. Additionally, nitrites and reactive oxygen species (ROS) production were evaluated.

Results

Cystatin Cinhibited the growth of P. gingivalis without affecting HGFs. Incubation of HGFs with P. gingivalis led to a significant increase of TNF-α and IL-1β. In contrast, HGFs incubated with P. gingivalis exposed to cystatin C showed a decreased production of both cytokines, whereas IL-10 was enhanced. Incubation of HGFs with P. gingivalis led to an increase of nitric oxide (NO) and ROS production, which was reduced in the presence of the peptide.

Conclusions

Cystatin C inhibits the growth of P. gingivalis and decreases the inflammatory cytokines, ROS, and NO production during infection of HGFs with P. gingivalis. Knowledge on the antimicrobial and immunomodulatory properties of cystatin C could aid in the design of new therapeutic approaches to facilitate the elimination of this bacterium to improve the treatment of periodontal disease.

Pilot Study of Use of Nitric Oxide in Monitoring Multiple Dental Foci in Oral Cavity—A Case Report

Background: The most common cause of implant loss and deteriorating restoration aesthetics is infection and chronic inflammation of the tissues around the implants. Inflammation in the oral cavity, confirmed by clinical and histopathological examination and determination of exhaled nitric oxide, is a situation which may cause the complications on the whole human body. Elimination of the patology in the oral cavity in some cases is the only resonable treatment. The aims and objectives of our work is to present a gradual treatment of advanced infalmmation and present huge reduction stamp of inflammation measured with marker nitric oxide (NO) in exhaled air. Materials and Methods: Simple treatment containing elimantion of pathology in the oral cavity was conducted. Patient that came to the dental practice suffered from the inflammation caused by lack of proper hygiene. First aid in this situation was to eliminate the inflammation which may affect negatively for general health. At first visit full hygienization was performed, at the second visit roots of abutment teeth and implants were removed under local anesthesia along with cystic changes. Results: The hygiene precedures and extraction of the unsteady inflammationprosthetic restorations significantly decreased the level of NO in exhaled air. Conclusions: During the examination of the patient coming to the dental practice great attention should be paid to the coexistence of pathologies related to the oral cavity. Omission of a dental examination and possible elimination of odontogenic foci may affect the implication of the results of general diagnostics and subsequent treatment. Measuring the level of NO on exhaled air seems to be useful diagnostic method.

Short-term effect of ligature-induced periodontitis on cardiovascular variability and inflammatory response in spontaneously hypertensive rats

Background

We previously reported that periodontal disease (PD) induces high arterial pressure variability (APV) consistent with sympathetic overactivity and elicits myocardial inflammation in Balb/c mice. However, it is unknown whether PD can change APV and heart rate variability (HRV) in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. This study aimed to evaluate the hemodynamic level, HRV, and APV associating with myocardial inflammation and plasma concentrations of oxide nitric (NO) in SHR and WKY rats with PD.

Methods

Three weeks after bilateral ligation of the first mandibular molar, or Sham operation, the rats received catheters into the femoral artery and had their arterial pressure (AP) recorded the following day. Subsequently, plasma, heart, and jaw were collected. The NO was quantified by the chemiluminescence method in plasma, and the myocardial IL-1β concentrations were evaluated by ELISA. In the jaw was evaluated linear alveolar bone loss induced by PD.

Results

The linear alveolar bone loss in jaws of SHR with PD was higher than in all other groups. AP and heart rate were higher in SHR than in their WKY counterparts. SHR with PD showed lower AP than control SHR. HRV and APV were different between SHR and WKY rats; however, no differences in these parameters were found between the animals with PD and their control counterparts. Plasma NO and myocardial IL-1β concentrations were higher in SHR with PD as compared to control WKY. A significant correlation was found between linear alveolar bone loss and plasma NO and myocardial IL-1β concentrations.

Conclusion

Our results demonstrated that short-term PD lowered the AP in SHR, which might be due to the higher levels of plasma NO. Even though PD did not affect either HRV or APV, it did induce myocardial inflammation, which can determine cardiovascular dysfunction in long-term PD.

Nitrite in paraffin-stimulated saliva correlates with blood nitrite

Nitrite anion (NO₂^-) is a circulating nitric oxide (NO) metabolite considered an endothelial function marker. Nitrite can be produced from nitrate (NO₃^-) secreted from plasma into saliva. The nitrate reductase of oral bacteria converts salivary nitrate to nitrite, which is swallowed and absorbed into circulation. In this study, we aimed to examine the relevance between these species' salivary and blood levels. We collected three whole saliva samples (unstimulated, paraffin-stimulated, and post-chlorhexidine mouthwash stimulated saliva) and blood from 75 healthy volunteers. We measured the nitrite and nitrate by the chemiluminescence method. The nitrite levels in stimulated saliva and post-mouthwash stimulated saliva exhibited weak correlations with blood nitrite. There was no correlation between nitrite in unstimulated saliva with blood nitrite. The baseline platelet activity, determined as P-selectin expression, negatively correlated with nitrite in plasma and post-mouthwash stimulated saliva. The salivary nitrate in all saliva samples showed correlations with its plasma levels. We conclude that nitrite in stimulated saliva correlates with blood nitrite.

Tobacco Use and Periodontal Disease-The Role of Microvascular Dysfunction

Periodontal disease consists in highly prevalent wide-ranging inflammatory conditions that affect the supporting apparatus of teeth. Tobacco use is the most important risk factor for periodontal disease as it increases disease severity and periodontal surgery complications. Tobacco use is harmful for the vasculature by causing microvascular dysfunction, which is known to negatively affect periodontal disease. To the author's knowledge this paper is the first comprehensive review on the mechanisms by which tobacco use affects oral microcirculation and impacts the pathophysiology of periodontal disease. In healthy subjects, acute nicotine administration or tobacco use (smoking/smokeless forms) increases the blood flow in the oral mucosa due to local irritation and increased blood pressure, which overcome neural- and endocrine-mediated vasoconstriction. Chronic tobacco smokers display an increased gingival microvascular density, which is attributed to an increased capillary recruitment, however, these microcirculatory units show higher tortuosity and lower caliber. These morphological changes, together with the repetitive vasoconstrictive insults, contribute to lower gingival perfusion in chronic smokers and do not completely regress upon smoking cessation. In periodontal disease there is considerable gingival inflammation and angiogenesis in non-smokers which, in chronic smokers, are considerably suppressed, in part due to local immune suppression and oxidative stress. Tobacco exposure, irrespective of the form of use, causes long-term microvascular dysfunction that increases the risk of complications due to the natural disease course or secondary therapeutic strategies.

Measurement of the Level of Nitric Oxide in Exhaled Air in Patients Using Acrylic Complete Dentures and with Oral Pathologies

The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring of the pathologies in the respiratory system but also in the oral cavity. Researchers have shown a huge increase of its level in asthma and diseases in the oral cavity. It seems reasonable to research the impact of pathologies in the oral cavity on the level of NO in exhaled air. The purpose of this study was to determine the impact of inflammation in the oral cavity (according to the material of dentures) on the level of nitric oxide in exhaled air. Three groups of patients were examined in this study. The hygiene of acrylic dentures, hard tissues, periodontal tissues, hygiene of the oral cavity, and level of NO in exhaled air were examined. Prosthetic stomatitis, denture plaque, tooth decay, poor sanitation and periodontitis increase levels of NO.

Localized probiotic-guided pocket recolonization in the treatment of chronic periodontitis: a randomized controlled clinical trial

Purpose

This randomized clinical placebo-controlled trial was conducted to evaluate the effectiveness of Lactobacillus reuteri as a probiotic in guided pocket recolonization (GPR) for the treatment of chronic periodontitis (CP) adjunctive to scaling and root planing (SRP).

Methods

Forty-eight CP patients were randomly assigned to 3 treatment groups: group 1 (SRP+placebo), group 2 (SRP+single application of probiotic), and group 3 (SRP+incremental application of probiotic). Clinical parameters were evaluated at baseline and at 8, 12, and 24 weeks, whereas biochemical parameters were measured at baseline and 12 weeks.

Results

At 24 weeks, the probing pocket depth and clinical attachment level improved in all 3 groups from baseline with no significant intergroup differences; however, a statistically significant difference was observed in localized plaque and gingival scores between groups 1 and 3 (P<0.05). At 12 weeks, matrix metalloproteinase-8 (MMP-8), nitric oxide (NO), and gingipains-R (Rgps) levels improved in all 3 groups, with statistically significant differences between groups 1 and 3 for MMP-8 and NO (P<0.05), but no difference for Rgps levels.

Conclusions

Within its limitations, the results of this study show that incremental 3-time application of L. reuteri as a probiotic led to improvements in clinical and biochemical parameters. This protocol can be a useful adjunct to SRP in the non-surgical management of CP.

Trial Registration

Clinical Trials Registry - India Identifier: CTRI/2017/03/008231

In vitro activities of Acacia nilotica (L.) Delile bark fractions against Oral Bacteria, Glucosyltransferase and as antioxidant

BACKGROUND

Dental caries and periodontal disease are the most common chronic infectious oral diseases in the world. Acacia nilotica was commonly known in Sudan as Garad or Sunt has a wide range of medicinal uses. In the present study, antibacterial activity of oral bacteria (Streptococcus sobrinus and Porphyromonas gingivalis), inhibitory activity against glucosyltransferase (GTF) enzyme and antioxidant activity were assayed for methanolic crude extract of A. nilotica bark and its fractions.

METHODS

Methanoilc crude extract of A. nilotica bark was applied to a Sephadex LH-20 column and eluted with methanol, aqueous methanol, and finally aqueous acetone to obtain four fractions (Fr1- Fr4). Furthermore, the crude extract and fractions were subjected to analytical high performance liquid chromatography (HPLC). The crude extract and its fractions were assayed for antibacterial activity against S. sobrinus and P. gingivalis using a microplate dilution assay method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), as well as GTF inhibition and antioxidant activity using ABTS radical scavenging method.

RESULTS

Fractions (Fr1 and Fr2) exhibited MIC values of 0.3 mg/ml against the P. gingivalis. Additionally, Fr2 displayed MBC value of 1 mg/ml against two types of bacteria. Fr4 showed an especially potent GTF inhibitory activity with IC₅₀ value of 3.9 μg/ml. Fr1 displayed the best antioxidant activity with IC₅₀ value of 1.8 μg/ml. The main compound in Fr1 was identified as gallic acid, and Fr2 was mostly a mixture of gallic acid and methyl gallate.

CONCLUSIONS

The results obtained in this study provide some scientific rationale and justify the use of this plant for the treatment of dental diseases in traditional medicine. A. nilotica bark, besides their antibacterial potentiality and GTF inhibitory activity, it may be used as adjuvant antioxidants in mouthwashes. Further studies in the future are required to identify the rest of the active compounds.

Systemic treatment with alpha-tocopherol and/or sodium selenite decreases the progression of experimental periodontitis

OBJECTIVE

To investigate the effects of sodium selenite (Se) and/or α-tocopherol (αT) applications on the alveolar bone loss (ABL), the number of gingival collagen fibers, inducible nitric oxide synthase (iNOS)+ and CD95+ cell numbers, and serum cytokine concentrations in experimental periodontitis in rats.

MATERIALS AND METHODS

Forty Sprague Dawley rats were divided into four groups of ten as follows: group A: Se group, group B: αT group, group C: Se and αT combined group, and group D: control group (intraperitoneal (IP) saline injection applied). Using the image analysis method in the connective tissue under the connective epithelium, the numbers of iNOS, CD95 positive cells, and collagen fibers were counted. ELISA kits were used to test the concentrations of serum interleukin (IL)-1β, IL-6, and IL-4.

RESULTS

The combination of Se and αT (group C) suppressed ABL compared with the control group (group D) (P < 0.05). In group A (Se), the number of iNOS+ cells was smaller than in group D (P < 0.05).

CONCLUSION

Se has been concluded to inhibit inflammation of the gum due to iNOS. Se and αT can have a remarkable important role in preventing alveolar bone loss, and particularly in combination.

CLINICAL RELEVANCE

Se and/or αT application may be useful in preventing the destruction of periodontal tissue and treatment of periodontal disease.

Mast cells exhibit intracellular microbicidal activity against Aggregatibacter actinomycetemcomitans

BACKGROUND AND OBJECTIVE

Several studies have demonstrated that mast cells are equipped with versatile tools to combat and kill bacteria. Additionally, mast cells produce and secrete a variety of mediators, which either regulate the host's immune system or directly attack bacteria. In this study, the intracellular microbicidal capacity of mast cells against Aggregatibacter actinomycetemcomitans was evaluated.

METHODS

Murine mast cells were challenged in vitro with A actinomycetemcomitans for 3, 5, 10, and 24 hours. Subsequently, the colony-forming units were counted. Additionally, the production and release of nitric oxide and hydrogen peroxide were analyzed by DAF-FM diacetate, the Griess reaction, and the Amplex Red kit, respectively. Cell death was evaluated using FITC Annexin V and propidium iodide staining.

RESULTS

Mast cells are able to efficiently eliminate periodontopathogen, with best results after 10 hours of intracellular challenge. The production/release of nitric oxide-and to a lesser extent of hydrogen peroxide-by mast cells was in agreement with its microbicidal capacity. Ninety percent of the mast cells  maintained their cellular viability even after 24 hours of bacterial challenge.

CONCLUSIONS

This is-to the best of our knowledge-the first report to describe the intracellular microbicidal activity of mast cells against A actinomycetemcomitans, concerning the production and release of potentially bactericidal substances. Further, the low number of cell deaths confirms that the decreased number of colony-forming units was due to the higher antimicrobial activity of mast cells. The results highlight the importance of these cells in the defense mechanisms of biofilm-induced periodontal disease.

Protective effects of desipramine on alveolar bone in experimental periodontitis

BACKGROUND

Desipramine is a tricyclic antidepressant with immune-modulatory activity, whose effects on ligature-induced periodontitis are yet to be investigated. Hence, its actions on alveolar bone resorption, gingival collagen content and key inflammatory mediators were herewith analyzed.

METHODS

A total of 60 male Wistar rats were randomly assigned into three groups: 1) control: rats without ligature treated with vehicle (saline); 2) ligature: rats with ligature-induced periodontitis treated with vehicle; 3) ligature + desipramine: rats with ligature-induced periodontitis treated with desipramine (20 mg/kg/d in vehicle). Mandibles and gingival tissues were collected 3 or 15 days after ligature insertion (or no ligature insertion for controls) and treatments. Alveolar bone resorption and gingival collagen fibers were histologically analyzed using either HE or picrosirius red staining. Gingival mRNA expressions of interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 were obtained through reverse transcription polymerase chain reaction. MMP-9 activity was analyzed by zymography.

RESULTS

Alveolar bone loss was significantly reduced in the ligature + desipramine group (P < 0.05), whereas gingival collagen degradation was like the ligature group (P > 0.05). Desipramine administration downregulated mRNA expressions of IL-1β, iNOS, COX-2, and TIMP-1 when compared to vehicle alone in the ligature group (P < 0.05). MMP-9 expression and MMP-9/TIMP-1 ratio were similar among rats with ligature-induced periodontitis (P > 0.05); however, MMP-9 activity was lower in the group treated with desipramine (P < 0.05).

CONCLUSION

Desipramine administration reduced alveolar bone loss as histologically observed, and modulated key bone remodeling and inflammatory mediators in rats with ligature-induced periodontitis.

Gender Differences in the Levels of Periodontal Destruction, Behavioral Risk Factors and Systemic Oxidative Stress in Ischemic Stroke Patients: A Cohort Pilot Study

Background: Due to the higher frequency of ischemic stroke in men compared to women, we aimed to determine if gender differences exist regarding periodontal status and several plasma biomarkers in patients with a recent large artery atherosclerosis ischemic stroke (IS). Material and methods: Patients with their first IS within less than six weeks who were able to undergo periodontal examinations were evaluated. Demographic data, periodontal status, oxidative stress parameters/plasma antioxidant capacity, and C-reactive protein in patients who suffered a recent large artery atherosclerosis ischemic stroke were reccorded. Results: 93 patients were included in the study. More men were smokers (12/57 vs. 3/36) and consumed alcohol (17/57 vs. 3/36), and more women had higher glycemic values (p = 0.023), total cholesterol (p < 0.001), LDL (low-density lipoprotein)-cholesterol (p = 0.010), and HDL (high-density lipoprotein)-cholesterol (p = 0.005) levels. Significantly more men than women had moderate plus severe periodontal disease (p = 0.018), significantly higher levels of nitric oxide (p = 0.034), and significantly lower levels of total antioxidant capacity (p = 0.028). Conclusions: In this pilot study, men seem to be more prone to oxidative stress and to develop more severe forms of periodontitis among patients with stroke, but the results need validation on a larger sample.

Association between Periodontal Health and Stroke: Results from the 2013-2015 Korea National Health and Nutrition Examination Survey (KNHANES)

Background/purpose

As the population ages, the prevalence of stroke increases, and as such there has been increasing interest in the risk factors associated with stroke. Although an association between periodontitis and stroke has been suggested, there has been no study of this association among the Korean population. Therefore, we investigated the association between periodontal health and stroke among Korean adults.

Materials and methods

A total of 9497 adults aged ≥40 years representing the Korean population were included in this cross-sectional study from the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2013–2015). Periodontitis was diagnosed by dentists based on the Community Periodontal Index (CPI). Also, participants filled out a questionnaire regarding their experience of doctor-diagnosed stroke. Hypertension, diabetes, body mass index (BMI), and oral hygiene behavior covariates were adjusted in logistic regression analysis.

Results

The mean age of the study population was 55.71 ± 0.17 years and 52.7% of them were female. Also, 248 people had a history of having a stroke. Results of the logistic regression analysis after adjusting for age and sex showed a significant relationship between oral health behavior, periodontal health, and stroke even after adjusting for age, sex, education, household income, national health insurance, employment status, alcohol, smoking, diabetes, hypertension, BMI, and oral health behaviors (odds ratio [OR], 1.71; 95% confidence interval [CI] = 1.03–2.85).

Conclusion

Our findings suggest that periodontitis is associated with stroke in Korean adults.

The Photomodulation Activity of Metformin Against Oral Microbiome

Periodontitis is one of the most common inflammatory diseases of the periodontium, which results in the inflammatory destruction of supporting structures around teeth and is closely associated with the development of systemic disease. Due to a wide variety of antibiotic resistance periodontopathic bacteria, photodynamic therapy (PDT) is a non-invasive adjunctive therapeutic modality that is capable of destroying the whole range of microbes. Metformin (Metf) is an antidiabetic drug, and recent studies suggest that cancer patients who receive Metf and are exposed to radiotherapy and chemotherapy show better outcomes. Our surveys in this review introduce Metf as a potent stimulus in increasing the efficacy of PDT in the induction of destruction in microbial cells.

Influence of acute high-intensity exercise on salivary nitric oxide levels

This study, employing an exercise versus control crossover design, was conducted to investigate the influence of acute high-intensity exercise on salivary nitric oxide (NO) levels. Nine healthy males (aged 23.8 ± 1.4 years) performed ergometer exercise at 80%VO_2peak for 60 min, whereas controls sat at rest for 60 min. Saliva samples were collected before (Pre: 0800 h) and after (Post 0-h: 0900 h, Post 1-h: 1000 h, Post 2-h: 1100 h, Post 3-h: 1200 h) the interventions. Salivary NO levels were determined by colorimetric assay. It was found that the salivary NO levels in controls were decreased (P < 0.05) at Post 0-h (-94 ± 15), Post 1-h (-80 ± 20), Post 2-h (-92 ± 34) and Post 3-h (-145 ± 39) relative to the Pre values. Under exercise conditions, salivary NO levels did not change after high-intensity ergometer exercise relative to the Pre values. Thus, the response of salivary NO levels appeared to differ between high-intensity ergometer exercise and inactivity, that exercise-related stress induces the production of salivary NO.

Oridonin inhibits LPS-induced inflammation in human gingival fibroblasts by activating PPARγ

Oridonin, the major terpene isolated from Rabdosia rubescens, has been used as dietary supplement. Recently, it has been known to exhibit anti-inflammatory effect. This study we employed an in vitro model of LPS-stimulated human gingival fibroblasts to investigate the anti-inflammatory effects and mechanism of oridonin. Oridonin (10-30 μg/mL) was administrated 1 h before LPS treatment. The results showed that oridonin significantly inhibited inflammatory mediators PGE₂, NO, IL-6, and IL-8 production. Immunoblotting experiments revealed that oridonin reduced the expression of phosphorylation levels of NF-κB p65 and IκBα. Furthermore, the expression of PPARγ was up-regulated by the treatment of oridonin. Further studies showed that PPARγ inhibitor GW9662 could reverse the inhibition of oridonin on PGE₂, NO, IL-6, and IL-8 production. In conclusion, oridonin inhibited LPS-induced microglia activation through activating PPARγ.

Contribution of Statins towards Periodontal Treatment: A Review

The pleiotropic effects of statins have been evaluated to assess their potential benefit in the treatment of various inflammatory and immune-mediated diseases including periodontitis. Herein, the adjunctive use of statins in periodontal therapy in vitro, in vivo, and in clinical trials was reviewed. Statins act through several pathways to modulate inflammation, immune response, bone metabolism, and bacterial clearance. They control periodontal inflammation through inhibition of proinflammatory cytokines and promotion of anti-inflammatory and/or proresolution molecule release, mainly, through the ERK, MAPK, PI3-Akt, and NF-κB pathways. Moreover, they are able to modulate the host response activated by bacterial challenge, to prevent inflammation-mediated bone resorption and to promote bone formation. Furthermore, they reduce bacterial growth, disrupt bacterial membrane stability, and increase bacterial clearance, thus averting the exacerbation of infection. Local statin delivery as adjunct to both nonsurgical and surgical periodontal therapies results in better periodontal treatment outcomes compared to systemic delivery. Moreover, combination of statin therapy with other regenerative agents improves periodontal healing response. Therefore, statins could be proposed as a potential adjuvant to periodontal therapy. However, optimization of the combination of their dose, type, and carrier could be instrumental in achieving the best treatment response.

Effects of coenzyme Q10 encapsulated in nanoliposomes on wound healing processes after tooth extraction

Background/purpose

Tooth extraction is often followed by a number of different complications that demand additional treatment. In order to accelerate healing processes and decrease the complication occurrence various agents, growth factors, natural and synthetic antioxidants (e.g coenzyme Q₁₀-CoQ₁₀), are applied. Due to the partially known health-promoting effects of CoQ₁₀ we decided to assess potential of it's encapsulated in nanoliposomes form on wound healing process following tooth extraction.

Materials and methods

Effects of free and encapsulated form of CoQ₁₀ on wound healing processes after tooth extraction in rats, 3 and 7 days following surgical procedure, was studied by means of tissue biochemical (myeloperoxidase activity and nitric oxide (NO) concentrations) and pathohistological analysis.

Results

The obtained results indicate that the encapsulated form of CoQ₁₀ compared to control and CoQ₁₀ treated animals statistically significantly decreases inflammatory process estimated through myeloperoxidase activity and NO concentrations, as well as based on histopathological analysis 3 and 7 days following surgery.

Conclusion

The results of this study unequivocally prove that the encapsulation of CoQ₁₀ in nanoliposomes enhances CoQ₁₀ activity by accelerating wound healing process after tooth extraction.

Effects of rosuvastatin on inducible nitric oxide synthase in rats with hyperlipidaemia and periodontitis

BACKGROUND AND OBJECTIVE

Nitric oxide is a free radical that is synthesized from l-arginine by nitric oxide synthase (NOS). The level of inducible NOS (iNOS) in gingiva with periodontitis is higher than that in healthy gingiva. The aim of this study was to evaluate the effects of rosuvastatin administration on alveolar bone loss (ABL) and iNOS(+) cell counts in gingival tissues in rats with ligature-induced experimental periodontitis with/without hyperlipidaemia.

MATERIAL AND METHODS

The rats were randomly divided into seven groups: Hy (cholesterol-added diet/water administration); HyP (cholesterol-added diet/periodontitis/water administration); HyPR (cholesterol-added diet/periodontitis/rosuvastatin administration); P (standard diet/periodontitis/water administration); PR (standard diet/periodontitis/rosuvastatin administration); C (standard diet/water administration); and R (standard diet/rosuvastatin administration). Experimental periodontitis was induced with silk ligatures, and rosuvastatin/water was administered to rats by oral gavage for the last 2 weeks of the 8-week study. After the rats were killed in week 8, histomorphometric and histological analyses were performed. Immunostained iNOS(+) cells were counted in the gingival samples and the Mann-Whitney U-test was used for statistical analysis.

RESULTS

The experimental groups exhibited increases in total cholesterol and low-density lipoprotein, except for Groups C and R. The cholesterol-added diet induced ABL in Group Hy. Of the periodontitis groups, the lowest ABL was found in Group PR. While there was a significant difference in ABL between Groups P (0.82 ± 0.15 mm) and PR (0.70 ± 0.21 mm) receiving a standard diet (P < .05), no difference was observed between Groups HyP (0.77 ± 0.07 mm) and HyPR (0.76 ± 0.11 mm) receiving a cholesterol-added diet (P ˃ .05). Rosuvastatin significantly reduced expression of iNOS in Groups PR (18.40 ± 2.31%) and HyPR (24.00 ± 4.83%) compared with Group P (30.90 ± 2.42%; P < .001). However, a larger number of iNOS(+) cells was found in Group HyPR than in Group PR (P < .001).

CONCLUSION

Administration of rosuvastatin reduced gingival iNOS expression in ligature-induced periodontitis with/without hyperlipidaemia. It also led to significant differences in ABL in rats with periodontitis, except when periodontitis was associated with hyperlipidaemia. These findings could provide an important contribution in further studies to evaluate the role of rosuvastatin as a host modulatory agent in the pathogenesis of periodontal diseases.

Oral health and systemic inflammatory, cardiac and nitroxid biomarkers in hemodialysis patients

Background

Periodontal diseases have systemic inflammatory effects and have been adversely associated with cardiovascular diseases, which are also the most frequent cause of death in the end-stage renal disease. The aim of this cross-sectional study was to investigate the oral health and serum biomarkers among the hemodialysis (HD) patients in Slovenia.

Material and Methods

111 HD patients were periodontally examined and their sera were assayed for C reactive protein (CRP), cardiac troponin T (TnT), nitrite/nitrate (NOx) and antibody levels to A. actinomycetemcomitans and P. gingivalis. The association of oral health with systemic response was analyzed with Kruskal-Wallis test, Fisher’s exact test and multivariate linear regression.

Results

Bleeding on probing without periodontal pockets was present in 5.2%, calculus without periodontal pockets in 42.1%, shallow periodontal pockets in 39.5% and deep periodontal pockets in 13.2% of dentate patients. There were 28.8% edentulous participants. 63.1% of the patients had CRP levels higher than 3 mg/L and 34.2% higher than 10 mg/L. TnT was detectable in all participants, with 25.2% exhibiting levels higher than 100 ng/L. The median level of NOx was 43.1 µmol/L. Participants with higher CRP were more likely to be edentulous and have higher TnT levels. A direct association of oral health with TnT or NOx was not detected.

Conclusions

HD patients in Slovenia have compromised oral health and increased serum inflammatory and cardiac biomarkers. Edentulousness was an independent predictor for the increased CRP, indicating a need for improved dental care to retain the teeth as long as possible.

Key words:Periodontal diseases, edentulousness, C reactive protein, cardiac troponin T, nitric oxide.

Inducible Nitric Oxide Synthase Polymorphisms and Nitric Oxide Levels in Individuals with Chronic Periodontitis

This study aimed to investigate whether the -1026(A>C)(rs2779249) and +2087(A>G)(2297518) polymorphisms in the NOS2 gene were associated with chronic periodontitis (CP) and with salivary levels of nitrite (NO₂^-) and/or nitrate + nitrite (NOx). A group of 113 mixed-race patients were subjected to periodontal, genetic, and biochemical evaluations (65 CP/48 periodontally healthy subjects). DNA was extracted from oral epithelial cells and used for genotyping by polymerase chain reaction (real-time). Salivary NOx concentrations were determined using an ozone-based chemiluminescence assay. Association of CP with alleles and genotypes of the -1026(A>C) polymorphism was found (X² test, p = 0.0075; 0.0308), but this was not maintained after multiple logistic regression, performed to estimate the effect of covariates and polymorphisms in CP. This analysis demonstrated, after correction for multiple comparisons, that only the female gender was significantly associated with CP. Polymorphisms analyzed as haplotypes were not associated with CP. NOx levels were significantly higher in the control group of heterozygous individuals for both polymorphisms. In conclusion, the female gender was significantly associated with CP, and higher levels of salivary NOx were found in control subjects and associated with the heterozygous state of the NOS2 polymorphisms, reinforcing the potential of NO metabolites as markers of periodontitis status.

Is the Level of Nitric Oxide in the Dental Follicular Tissues of Impacted Third Molars With a History of Recurrent Pericoronitis a True Marker of Oxidative Stress?

PURPOSE

Nitric oxide (NO) is an indicator of oxidative stress in several tissues. Its role in dental follicular (DF) tissues of impacted third molars with a history of recurrent pericoronitis is not well elucidated. The present study compared NO levels between inflamed and noninflamed DF tissues of impacted third molars with a history of recurrent pericoronitis.

MATERIALS AND METHODS

A cross-sectional study was designed. The study sample included inflamed DF tissues (test group) with certain local inflammatory symptoms, such as pain, tenderness, swelling, and erythema and noninflamed DF tissues (control group) without local inflammatory symptoms of impacted mandibular third molars. Each patient contributed only 1 specimen to the samples. All tissues samples were biochemically investigated for NO levels as an indicator of oxidative stress. The primary predictor variable was inflammatory status; secondary predictor variables were age and gender. The primary outcome variable was NO level. Descriptive and comparative analyses were conducted.

RESULTS

The test group consisted of 57 patients (28 men, 29 women; mean age, 23.28 ± 5.16 yr) and the control group consisted of 57 patients (30 men, 27 women; mean age, 23.02 ± 5.42 yr). No relevant intergroup differences were noted for demographic findings such as age and gender. NO levels were significantly higher in inflamed DF tissues of impacted third molars than in noninflamed DF tissues (P < .05).

CONCLUSION

Results of this study showed that NO might be used as an indicator of oxidative stress and the necessity to remove impacted mandibular third molars with a history of recurrent pericoronitis.

Effect of burdock extracts upon inflammatory mediator production

We investigated the burdock extract on the inhibitions of NO generation, COX-2 expression, and the generations of IL-6 and TNF-α , to find out its anti-inflammatory effect in this study. After the treatment of the burdock extract in the cells, we measured the amount of NO generated in the inflammatory cells developed by LPS and UVB, and confirmed the developments of inflammatory mediators by RT-PCR. Upon the results on the NO generation after the development of inflammation by LPS in Raw 264.7 cell, we found approximately 50% of inhibitory effect at 200 μg/ml concentrations of the burdock extract. It was confirmed that the expression levels of TNF-α, COX-2, and IL-6 were declined to the levels of control by LPS and UVB stimulated inflammation in HaCat cell. This means the anti-inflammatory effect of the burdock extract.

Validation of two point-of-care tests against standard lab measures of NO in saliva and in serum

Nitric oxide (NO) is an endogenous signaling molecule, which plays important roles in cardiometabolic health. A significant source of NO is dietary nitrate (NO3), which is initially metabolized by oral bacteria into nitrite (NO2-) and is subsequently converted into NO once digested in the acidic gastric environment. Inexpensive non-invasive tests for measuring nitrite from saliva have been developed as a means for individuals to monitor their NO bioavailability. However, few studies exist in the literature validating and comparing these products with standard lab assays. The objective of this study was to validate two commonly used commercial strips: Nitric Oxide Test Strips (Berkeley Test) and Nitric Oxide Indicator Strips (Neogenesis) against standard lab measures for saliva and serum nitrite/nitrate. A stratified random sample of 20 non-smoking, overweight or obese participants between 40 to 65 years of age, were selected for this study from the baseline data of the San Juan Overweight Adults Longitudinal Study (SOALS). There was a significant correlation between the measures from the two nitrite-detecting-strips after controlling for the stratification variables (metabolic syndrome, and mouthwash use) (r = 0.75). Measurements from both strips correlated significantly with salivary nitrite levels (r = 0.76 for Berkeley strips; r = 0.59 for Neogenesis). Neither of the strips had a significant correlation with the levels of saliva nitrate, serum nitrite and serum nitrate. In conclusion, commercially available Berkeley and Neogenesis strips provide a reasonable surrogate for salivary, but not for systemic nitrite levels.

NADPH Oxidase Contributes to Resistance against Aggregatibacter actinomycetemcomitans-Induced Periodontitis in Mice

Aggregatibacter actinomycetemcomitans is a Gram-negative commensal bacterium of the oral cavity which has been associated with the pathogenesis of periodontitis with severe alveolar bone destruction. The role of host factors such as reactive oxygen and nitrogen intermediates in periodontal A. actinomycetemcomitans infection and progression to periodontitis is still ill-defined. Therefore, this study aimed to analyze the role of NADPH oxidase and inducible nitric oxide synthase (iNOS) in a murine model of A. actinomycetemcomitans-induced periodontitis. NADPH oxidase-deficient (gp91^phox knockout [KO]), iNOS-deficient (iNOS KO), and C57BL/6 wild-type mice were orally infected with A. actinomycetemcomitans and analyzed for bacterial colonization at various time points. Alveolar bone mineral density and alveolar bone volume were quantified by three-dimensional micro-computed tomography, and the degree of tissue inflammation was calculated by histological analyses. At 5 weeks after infection, A. actinomycetemcomitans persisted at significantly higher levels in the murine oral cavities of infected gp91^phox KO mice than in those of iNOS KO and C57BL/6 mice. Concomitantly, alveolar bone mineral density was significantly lower in all three infected groups than in uninfected controls, but with the highest loss of bone density in infected gp91^phox KO mice. Only infected gp91^phox KO mice revealed significant loss of alveolar bone volume and enhanced inflammatory cell infiltration, as well as an increased number of osteoclasts. Our results indicate that NADPH oxidase is important to control A. actinomycetemcomitans infection in the murine oral cavity and to prevent subsequent alveolar bone destruction and osteoclastogenesis.

Heterogeneous Porphyromonas gingivalis LPS modulates immuno-inflammatory response, antioxidant defense and cytoskeletal dynamics in human gingival fibroblasts

Periodontal (gum) disease is a highly prevalent infection and inflammation accounting for the majority of tooth loss in adult population worldwide. Porphyromonas gingivalis is a keystone periodontal pathogen and its lipopolysaccharide (PgLPS) acts as a major virulence attribute to the disease. Herein, we deciphered the overall host response of human gingival fibroblasts (HGFs) to two featured isoforms of tetra-acylated PgLPS_1435/1449 and penta-acylated PgLPS₁₆₉₀ with reference to E. coli LPS through quantitative proteomics. This study unraveled differentially expressed novel biomarkers of immuno-inflammatory response, antioxidant defense and cytoskeletal dynamics in HGFs. PgLPS₁₆₉₀ greatly upregulated inflammatory proteins (e.g. cyclophilin, inducible nitric oxide synthase, annexins, galectin, cathepsins and heat shock proteins), whereas the anti-inflammatory proteins (e.g. Annexin A2 and Annexin A6) were significantly upregulated by PgLPS_1435/1449. Interestingly, the antioxidants proteins such as mitochondrial manganese-containing superoxide dismutase and peroxiredoxin 5 were only upregulated by PgLPS_1690. The cytoskeletal rearrangement-related proteins like myosin were differentially regulated by these PgLPS isoforms. The present study gives new insight into the biological properties of P. gingivalis LPS lipid A moiety that could critically modulate immuno-inflammatory response, antioxidant defense and cytoskeletal dynamics in HGFs, and thereby enhances our understanding of periodontal pathogenesis.

Smoking and gingivitis: focus on inducible nitric oxide synthase, nitric oxide and basic fibroblast growth factor

BACKGROUND

Periodontal disease pathogenesis has been associated with smoking. Gingivitis is a mild and reversible form of periodontal disease and it tends to progress to periodontitis only in susceptible individuals. In the present study, we aimed to examine the impact of smoking on host responses in gingivitis and to evaluate and compare the inducible nitric oxide synthase (iNOS) activity in gingival tissue and NO and basic fibroblast growth factor (bFGF) levels in the gingival crevicular fluid of patients with gingivitis and healthy individuals.

MATERIAL AND METHODS

Forty-one participants were assigned to the gingivitis-smoker (n = 13), gingivitis (n = 13), healthy-smoker (n = 7) and healthy groups (n = 8). Clinical indices were recorded; gingival biopsy and gingival crevicular fluid samples were obtained from papillary regions. iNOS expression was evaluated by immunohistochemical staining. The immunoreactive cells were semiquantitatively assessed. For the quantitative determination of nitrite and nitrate in gingival crevicular fluid, the NO assay kit was used. The amount of bFGF in gingival crevicular fluid was determined by enzyme-linked immunosorbent assay.

RESULTS

The gingivitis-smoker group demonstrated a stronger iNOS expression than the non-smoker gingivitis group. iNOS expression intensity was lower in the non-smoker healthy group compared to that in healthy-smokers. No significant gingival crevicular fluid NO and bFGF level changes were observed between groups. Among patients with gingivitis, a positive correlation was detected between gingival crevicular fluid NO and bFGF levels (r = 0.806, p = 0.001).

CONCLUSIONS

Our data suggest that smoking has significant effects on iNOS expression but not on gingival crevicular fluid NO or bFGF levels in healthy and patients with gingivitis. However, our results suggest that bFGF might be involved in the regulation of NO production via iNOS.

Using Salivary Nitrite and Nitrate Levels as a Biomarker for Drug-Induced Gingival Overgrowth

Aim: Drug-induced gingival overgrowth has a multifactorial nature and the pathogenesis is still uncertain. It has been suggested that Nitric Oxide (NO) might play a role in the pathogenesis of drug-induced gingival overgrowth due to the contribution of NO to immune response and matrix degradation. NO levels in biological fluids have been used as a diagnostic biomarker in many diseases. The aim of this study is to determine whether NO levels in plasma, saliva, and gingival crevicular fluid (GCF) can serve as a potential biomarker for the evaluation of drug-induced gingival overgrowth risk.

Materials and Methods: A total of 104 patients, receiving cyclosporine A (n = 35), phenytoin (n = 25), nifedipine (n = 26), or diltiazem (n = 18) participated in the study. The amount of gingival overgrowth was evaluated with two indices and was given as percentage. Periodontal clinical parameters including plaque index (PI), gingival index (GI), gingival bleeding time index (GBTI), and probing depth (PD) were also assessed. Saliva, GCF, and plasma samples were obtained from each participants. Nitrite and nitrate levels in saliva, GCF, and plasma were analyzed by Griess reagent.

Results: Salivary nitrite and nitrate levels in responders were significantly higher than those in non-responders in only phenytoin group (p < 0.05). Nitrite and nitrate levels of gingival crevicular fluid and plasma did not significantly differ between responders and non-responders in all study groups (p > 0.05). Salivary nitrite levels exhibited a significant correlation with PD, GBTI, severity of gingival overgrowth (%GO), and GCF volume (p < 0.05). Additionally, a strong positive correlation was detected between saliva and plasma nitrate levels (p < 0.005). However, both nitrite and nitrate levels in GCF and plasma demonstrated no significant correlation with clinical parameters, GO severity, and GCF volume (p > 0.05).

Conclusion: Salivary nitrite and nitrate levels could be used as periodontal disease biomarkers in phenytoin induced gingival overgrowth, and that saliva seems to have a better diagnostic potential than GCF and plasma for the evaluation of drug-induced gingival overgrowth risk. However, when all drug groups were considered, saliva nitrite and nitrate levels could not be used as a biomarker for drug-induced gingival overgrowth.

Production and physiological role of NO in the oral cavity

Nitric oxide (NO) is a free radical which is produced from a wide variety of cells and tissues in the human body. NO is involved in the regulation of many physiological processes, such as vascular relaxation, neurotransmission, immune regulation, and cell death. NO is generated by nitric oxide synthase (NOS), which has three identified isoforms: neuronal type NOS (nNOS), endothelial type NOS (eNOS), and inducible type NOS (iNOS). Different isoforms are expressed depending on the organs, tissues, and cells, and investigation of the types and functions of enzymes expressed in various tissues is underway. The oral cavity is a space in which marked changes have been detected in NO levels, and each tissue is constantly influenced by NO. NO is a component of saliva and is produced by oral bacteria in the oral cavity and released by NOS expressed in oral mucosa. NOS isoforms expressed under normal conditions differ among the oral organs. In addition, the overexpression of NOS was involved in carcinogenesis and tumor growth progression. This review summarized the expression of NOS and functions of NO in oral cavity organs, and their roles in diseases and the influences of treatments.

Host modulation therapy: An indispensable part of perioceutics

Traditionally, only antimicrobials have been used as the chemotherapeutic modality for the treatment of periodontitis. Though bacteria are the primary etiologic factors of periodontal diseases, yet the extent and severity of tissue destruction seen in periodontitis is determined by the host immuno-inflammatory response to these bacteria. This increasing awareness and knowledge of the host-microbial interaction in periodontal pathogenesis has presented the opportunity for exploring new therapeutic strategies for periodontitis by means of targeting host response via host-modulating agents. This has lead to the emergence of the field of "Perioceutics" i.e. the use of parmacotherapeutic agents including antimicrobial therapy as well as host modulatory therapy for the management of periodontitis. These host-modulating agents used as an adjunct tip the balance between periodontal health and disease progression in the direction of a healing response. In this article the host-modulating role of various systemically and locally delivered perioceutic agents will be reviewed.

Nitrite and nitrate levels of gingival crevicular fluid and saliva in subjects with gingivitis and chronic periodontitis

OBJECTIVES

Nitrosative stress plays an essential role in the pathogenesis of periodontal disease. The aim of this study is to analyze the gingival crevicular fluid and saliva nitrite and nitrate levels in periodontally healthy and diseased sites.

MATERIAL AND METHODS

A total of 60 individuals including, 20 chronic periodontitis and 20 gingivitis patients and 20 periodontally healthy controls participated in the present study. Probing depth, clinical attachment level, bleeding on probing, gingival index and plaque index were assessed, gingival crevicular fluid (GCF) and saliva samples were obtained from the subjects, including 480 GCF samples and 60 unstimulated whole saliva samples. Nitrite and nitrate were analyzed by Griess reagent.

RESULTS

Total GCF nitrite levels were higher in gingivitis and periodontitis groups (1.07 [SD 0.62] nmol and 1.08 [SD 0.59] nmol) than the control group (0.83 [SD 0.31] nmol) (P < 0.05) but did not differ significantly between gingivitis and periodontitis groups (P > 0.05). The difference in GCF nitrate level was not significant among the control, gingivitis and periodontitis groups (7.7 [SD 2.71] nmol, 7.51 [SD 4.16] nmol and 7.38 [SD 1.91] nmol). Saliva nitrite and nitrate levels did not differ significantly among three study groups. Saliva nitrate/nitrite ratios were higher in periodontitis and gingivitis groups than the control group. A gradual decrease in nitrate/nitrite ratio in GCF was detected with the presence of inflammation.

CONCLUSIONS

It may be suggested that nitrite in gingival crevicular fluid is a better periodontal disease marker than nitrate and may be used as an early detection marker of periodontal inflammation, and that local nitrosative stress markers don't show significant difference between the initial and advanced stages of periodontal disease.

Expression profiles of NOS isoforms in gingiva of nNOS knockout mice

Nitric oxide is a gaseous molecule associated with many distinct physiological functions, and is derived from L-arginine catalyzed by nitric oxide synthase (NOS). Nitric oxide synthase has 3 isoforms: nNOS, iNOS and eNOS. Although these NOS isoforms are believed to play an important role in gingival tissue, little information is available on their morphological dynamics. The aim of this study was to investigate the profiles of NOS isoforms in deficiency of nNOS in gingiva of mice. Twelve male (6 normal (C57BL/6) and 6 nNOS knockout) mice were used. All mice were 5-week-old, weighing approximately 20-25 g each. After sacrifice, the jaws of the mice were removed by mechanical means and specimens analyzed by histology, in situ hybridization and immunohistochemistry. Immunohistochemical observation revealed positive staining for iNOS and eNOS, especially in lamina propria. Similar results in the mRNA expression levels were shown by in situ hybridization analysis. It may suggest that iNOS and eNOS compensated nNOS deficiency in the gingiva of nNOS knockout mice.

Determination of nitrite in saliva using microfluidic paper-based analytical devices

Point-of-care platforms can provide fast responses, decrease the overall cost of the treatment, allow for in-home determinations with or without a trained specialist, and improve the success of the treatment. This is especially true for microfluidic paper-based analytical devices (μPAD), which can enable the development of highly efficient and versatile analytical tools with applications in a variety of biomedical fields. The objective of this work was the development of μPADs to identify and quantify levels of nitrite in saliva, which has been proposed as a potential marker of periodontitis. The devices were fabricated by wax printing and allowed the detection of nitrite by a colorimetric reaction based on a modified version of the Griess reaction. The presented modifications, along with the implementation of a paper-based platform, address many of the common drawbacks (color development, stability, etc.) associated with the Griess reaction and are supported by results related to the design, characterization, and application of the proposed devices. Under the optimized conditions, the proposed devices enable the determination of nitrite in the 10-1000 μmol L(-1) range with a limit of detection of 10 μmol L(-1) and a sensitivity of 47.5 AU [log (μmol L(-1))](-1). In order to demonstrate the potential impact of this technology in the healthcare industry, the devices were applied to the analysis of a series of real samples, covering the relevant clinical range.