Oxidative stress and recurrent aphthous stomatitis

Therapeutic applications of melatonin in disorders related to the gastrointestinal tract and control of appetite

Most animals have large amounts of the special substance melatonin, which is controlled by the light/dark cycle in the suprachiasmatic nucleus. According to what is now understood, the gastrointestinal tract (GIT) and other areas of the body are sites of melatonin production. According to recent studies, the GIT and adjacent organs depend critically on a massive amount of melatonin. Not unexpectedly, melatonin's many biological properties, such as its antioxidant, anti-inflammatory, pro-apoptotic, anti-proliferative, anti-metastasis, and antiangiogenic properties, have drawn the attention of researchers more and more. Because melatonin is an antioxidant, it produces a lot of secretions in the GIT's mucus and saliva, which shields cells from damage and promotes the development of certain GIT-related disorders. Melatonin's ability to alter cellular behavior in the GIT and other associated organs, such as the liver and pancreas, is another way that it functions. This behavior alters the secretory and metabolic activities of these cells. In this review, we attempted to shed fresh light on the many roles that melatonin plays in the various regions of the gastrointestinal tract by focusing on its activities for the first time.

Impact of Thermo-Responsive N-Acetylcysteine Hydrogel on Dermal Wound Healing and Oral Ulcer Regeneration

This study investigates the efficacy of a thermo-responsive N-acetylcysteine (NAC) hydrogel on wound healing and oral ulcer recovery. Formulated by combining NAC with methylcellulose, the hydrogel's properties were assessed for temperature-induced gelation and cell viability using human fibroblast cells. In vivo experiments on Sprague Dawley rats compared the hydrogel's effects against saline, NAC solution, and a commercial NAC product. Results show that a 5% NAC and 1% methylcellulose solution exhibited optimal outcomes. While modest improvements in wound healing were observed, significant enhancements were noted in oral ulcer recovery, with histological analyses indicating fully regenerated mucosal tissue. The study concludes that modifying viscosity enhances NAC retention, facilitating tissue regeneration. These findings support previous research on the beneficial effects of antioxidant application on damaged tissues, suggesting the potential of NAC hydrogels in improving wound care and oral ulcer treatment.

Systemic and local effect of oxidative stress on recurrent aphthous stomatitis: systematic review

Recurrent aphthous stomatitis (RAS) is a chronic and recurrent inflammatory disease of the mouth. It is characterised by the appearance of painful ulcers in the oral mucosa. RAS is believed to be a multifactorial disease with genetic predisposition, environmental factors and alterations in the immune system. Oxidative stress, caused by an imbalance between free radicals and the antioxidant system, also appears to be involved in the pathogenesis of RAS. Several risk factors, such as smoking, iron and vitamin deficiency and anxiety, may contribute to the development of the disease. Understanding the underlying mechanisms may help in the prevention and treatment of RAS. We searched PubMed, Scopus and Web of Science databases for articles on oxidative stress in patients with RAS from 2000 to 2023. Studies analysing oxidant and antioxidant levels in the blood and saliva of RAS patients and healthy controls were selected. Of 170 potentially eligible articles, 24 met the inclusion criteria: 11 studies on blood samples, 6 on salivary samples and 7 on both blood and salivary samples. Multiple oxidative and antioxidant markers were assessed in blood and saliva samples. Overall, statistically significant differences were found between RAS patients and healthy controls for most markers. In addition, increased oxidative DNA damage was observed in patients with RAS. Patients with RAS show elevated levels of oxidative stress compared to healthy controls, with a significant increase in oxidative markers and a significant decrease in antioxidant defences in saliva and blood samples.

Systematic review and meta-analysis of oxidative stress and antioxidant markers in recurrent aphthous stomatitis

BACKGROUND

We performed this systematic review and meta-analysis to synthesize all studies that reported the level of oxidative and antioxidative markers in recurrent aphthous stomatitis (RAS) patients compared to controls.

METHODS

We registered our study in PROSPERO (CRD42023431310). PubMed, ProQuest, Scopus, EMBASE, Google Scholar, and Web of Science were searched to find relevant publications up to June 5, 2023. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated. We included 30 articles after multiple stags of screening.

RESULTS

We found that erythrocyte superoxide dismutase and Glutathione peroxidase activity were significantly lower in patients with RAS compared to healthy controls (SMD = - 1.00, 95%CI = -1.79 to -0.21, p = 0.013, and SMD = - 1.90, 95%CI = -3.43 to -0.38, p = 0.01, Respectively). However, there was not any difference between patients with RAS and healthy controls in erythrocyte Catalase (SMD = - 0.71, 95%CI = -1.56-0.14, p = 0.10). The total antioxidant status (TAS) level, in serum was significantly lower in patients than healthy controls (SMD = - 0.98, 95%CI = -1.57 to -0.39, p = 0.001). In addition, RAS patients had higher levels of serum Malondialdehyde (MDA), Serum total oxidant status, and serum oxidative stress index than healthy controls (SMD = 2.11, 95%CI = 1.43-2.79, p < 0.001, SMD = 1.53, 95%CI = 0.34-2.72, p = 0.01, and SMD = 1.25, 95%CI = 0.25-2.25, p = 0.014, Respectively); However, salivary MDA and TAS, and serum uric acid, vitamin E and C, and reduced glutathione levels of patients with RAS were not different from that of healthy controls.

CONCLUSIONS

The relationship between oxidative stress and RAS is well established in this meta-analysis. Although the molecular processes underlying the etiology of this pathology remain unknown, evidence indicating oxidative stress has a significant role in the pathogenesis of RAS has been revealed.

The Evaluation of Healing Properties of Galium verum-Based Oral Gel in Aphthous Stomatitis in Rats

Although oral ulcers represent one of the most frequent oral mucosal diseases, the available treatment is not sufficient to provide complete ulcer recovery without side-effects. Therefore, the aim of our study was to prepare a mucoadhesive oral gel based on Galium verum ethanol extract (GVL gel) and reveal its healing effects in the model of aphthous stomatitis in rats. Rats with oral ulcers were divided into the following groups: control (untreated), gel base (ulcer was treated with the gel base, three times per day for 10 days), and GVL gel group (the ulcer was treated with GVL gel in the same way as the gel base). Animals from each group were sacrificed on days 0, 3, 6, and 10 for collecting blood and ulcer tissue samples. Healing properties of oral gel were determined by clinical evaluation, as well as biochemical and histopathological examinations. Our findings suggest a significant decrease in the ulcer size in GVL gel group, with healing effects achieved through the alleviation of oxidative stress, reduction in COX-2 immunopositivity, and increase in collagen content in buccal tissue. Significant ulcer repairing potential of GVL gel highlights this oral mucoadhesive gel as a promising tool for prevention and treatment of RAS.

Targeting Nrf2 with Probiotics and Postbiotics in the Treatment of Periodontitis

Periodontitis is a destructive disease of the tooth-surrounding tissues. Infection is the etiological cause of the disease, but its extent and severity depend on the immune–inflammatory response of the host. Immune cells use reactive oxygen species to suppress infections, and there is homeostasis between oxidative and antioxidant mechanisms during periodontal health. During periodontitis, however, increased oxidative stress triggers tissue damage, either directly by activating apoptosis and DNA damage or indirectly by activating proteolytic cascades. Periodontal treatment aims to maintain an infection and inflammation-free zone and, in some cases, regenerate lost tissues. Although mechanical disruption of the oral biofilm is an indispensable part of periodontal treatment, adjunctive measures, such as antibiotics or anti-inflammatory medications, are also frequently used, especially in patients with suppressed immune responses. Recent studies have shown that probiotics activate antioxidant mechanisms and can suppress extensive oxidative stress via their ability to activate nuclear factor erythroid 2-related factor 2 (Nrf2). The aim of this narrative review is to describe the essential role of Nrf2 in the maintenance of periodontal health and to propose possible mechanisms to restore the impaired Nrf2 response in periodontitis, with the aid of probiotic and postbiotics.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusion

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

Combined signatures of serum proteome and transcriptome in patients with recurrent aphthous ulcer

OBJECTIVES

Recurrent aphthous ulcer (RAU) is a common oral disease with unclear mechanism. This study aimed to explore the serum signatures of RAU patients via proteomic and transcriptomic analysis.

METHODS

This study was based on clinical observation. Part of serum was used for clinical tests, while the rest was processed for isobaric tags for relative and absolute quantitation (ITRAQ) labeling coupled with two-dimensional liquid chromatography-tandem mass spectrometry (2D LC-MS/MS) combined with microRNA (miRNA) microarrays. Bioinformatic analysis was then used to obtain significant signatures, which was verified by ELISA, qRT-PCR, and dual-luciferase reporter gene assays.

RESULTS

Clinical data showed that triglyceride level, white blood cell count, and neutrophils percentage were increased in RAU group, while lymphocytes percentage was decreased. ITRAQ-2D LC-MS/MS identified 22 upregulated and 33 downregulated proteins in RAU group. Simultaneously, miRNA microarrays identified 64 upregulated and 31 downregulated miRNAs. After integrative bioinformatic analysis and verification, three miRNA-protein pairs, mainly involved in oxidative stress and inflammation responses, were obtained. Additionally, the interaction network indicated the crucial role of complement and coagulation cascade pathway in RAU.

CONCLUSIONS

Our study revealed that complement and coagulation cascade pathway, oxidative stress, and inflammation responses may act as vital factors in pathogenesis of RAU.

The evaluation of thiol/disulphide homeostasis in recurrent aphthous stomatitis

The objective of our study was to determine thiol/disulphide homeostasis in recurrent aphtous stomatitis (RAS) patients. A prospective monocentric study was designed. Forty-three recurrent aphtous stomatitis patients and 43 healthy subjects were included to study. Venous blood samples collected and assessed with novel automatic system. Results compared statistically. Disulphide levels were found significantly higher in RAS patients than control group. There was no significant difference between native thiol and total thiol levels. Thiol/disulphide homeostasis is impaired in RAS patients in favor of disulphide levels compared with control group. To the best of our knowledge, the present study is the first examination on the correlation between thiol and disulfide homeostasis in patients with RAS.

The Effect of Photobiomodulation on Nitrite and Inflammatory Activity in Radiotherapy-Induced Oral Mucositis: A Randomized Clinical Trial

BACKGROUND AND OBJECTIVES

To investigate pro- and anti-inflammatory cytokines and nitrite salivary levels in patients with head and neck cancer receiving photobiomodulation therapy (PBMT) associated with a Preventive Oral Care Program (POCP), for prevention and control of oral mucositis (OM) during radiotherapy (RT) associated or not with chemotherapy protocol.

STUDY DESIGN/MATERIALS AND METHODS

In this randomized double-blinded clinical trial, 48 patients were randomly assigned to two groups: PBMT (n = 25) and Control (n = 23). In the PBMT group, patients were submitted to PBMT associated with the POCP. In the Control group, patients were submitted only to the POCP. Saliva samples were collected in the 1st (baseline), 7th, 14th, 21st, and 30th sessions of RT, and the levels of interleukin-6 (IL-6), IL-8, IL-10, IL-12p70, IL-1β, and tumoral necrosis factor-α (TNF-α) were measured using the cytometric bead array. Nitrite levels were measured by colorimetric method. OM was assessed using the World Health Organization and the National Cancer Institute scales.

RESULTS

Patients in the PBMT group presented less severe OM. PBMT tended to stabilize nitrite concentration levels during the RT regimen. The IL-1β concentration was associated with higher OM scores. PBMT promoted an increase in IL-12p70, TNF-α, and IL-10 concentration.

CONCLUSION

PBMT was effective in the prevention and control of severe OM, and its mechanism of action may be related to a better balance of inflammatory response that may favor injury control. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Enhanced In Situ Availability of Aphanizomenon Flos-Aquae Constituents Entrapped in Buccal Films for the Treatment of Oxidative Stress-Related Oral Diseases: Biomechanical Characterization and In Vitro/Ex Vivo Evaluation

In recent years, the key role of oxidative stress in pathogenesis of oral diseases has been emphasized and the use of antioxidant agents has been encouraged. Aphanizomenon flos-aquae (AFA) is a unicellular blue-green alga with antioxidant and anti-inflammatory properties. The aim of this study was the formulation and characterization of mucoadhesive thin layer films loaded with AFA, finalized to the treatment of oxidative stress (OS)-related oral diseases. First, to enhance the bioavailability of AFA constituents, the raw food grade material was appropriately treated by a high frequency homogenization able to disrupt cell walls. Thus, Eudragit^® E100-based buccal films were produced by the solvent casting method, containing 7% and 18% of AFA. The films, characterized by uniformity in thickness, weight, and drug content, showed low swelling degree, good muco-adhesiveness and controlled drug release. The mechanical tests showed elastic moduli of films of almost 5 MPa that is well-suitable for human buccal applications without discomfort, besides biaxial tests highlighted a marked material isotropy. Permeation studies through porcine mucosae demonstrated the ability of films to promote AFA penetration in the tissues, and when sublingually administered, they produced a drug flux up to six-fold higher than an AFA solution. The new formulations represent an interesting alternative for the development of cosmetics and nutraceuticals with a functional appeal containing plant extracts.

Evaluation and Comparison of Total Antioxidant Capacity of Saliva Between Patients with Recurrent Aphthous Stomatitis and Healthy Subjects

Background & Objectives:

Recurrent Aphthous Stomatitis (RAS) is one of the most common chronic ulcerative lesions of the oral mucosa and its development may be associated with oxidative stress. The aim of this study was to evaluate salivary Total Antioxidant Capacity (TAC) in patients with minor RAS.

Materials & Methods:

In this case-control study, 27 patients with minor RAS and 28 age- and sex-matched controls without RAS were enrolled. TAC was measured in unstimulated saliva for patients (during active lesion phase and after healing) and controls by immunologic assay. Data were analyzed by SPSS 18 using paired and unpaired t-tests (P<0.05).

Results:

Salivary TAC levels of patients presented a significant increase from active lesion phase (0.26±0.16) to healing time (0.43±0.41); (P=0.034). There was no significant difference in the level of salivary TAC between patients during active lesion phase and controls (0.24±0.13); (P=0.641).

Conclusion:

Increasing level of salivary TAC may be involved in remission of RAS lesions, suggesting its evaluation in future studies.

Recurrent aphthous ulceration: a review of potential causes and novel treatments

Purpose of article: This review examines studies published between May 2012 and 2017 with a specific interest in potential recurrent aphthous ulceration (RAU) etiologies and treatment modalities/efficacy, including topical treatments, systemic regimens, vitamin repletion, and laser therapy, among others.

MATERIALS AND METHODS

PubMed MEDLINE and Cochrane Database of Systematic Reviews were searched using various combinations of: 'aphthous', 'ulcer', and 'treatment'. The titles and abstracts from the initial literature search were appraised to identify articles for full review and reference sections from each article were searched manually for relevant publications. Both randomized controlled trials and observational reports were included in this review, as some treatment types have not been formally examined in randomized trials. Relevant studies were reviewed, compared, and summarized.

RESULTS

RAU can result from systemic disease and trauma, but recent studies have shown a variety of potential etiologies, ranging from vitamin deficiencies, oral microbiota derangements, hematological considerations, stress, genetic polymorphisms to oxidant-antioxidant imbalances, among others. Many modalities of therapy are available and have proven efficacious.

CONCLUSIONS

As the exact etiology of RAU is still unknown, therapy is based on symptomatic relief.

The anti-oxidant effects of melatonin derivatives on human gingival fibroblasts

OBJECTIVES

Aim of this in vitro study was to evaluate the anti-oxidant activity of indole ring modified melatonin derivatives as compared with melatonin in primary human gingival fibroblast (HGF) cells.

METHODS

Anti-oxidant activity of melatonin (MLT), acetyl-melatonin (AMLT) and benzoyl-melatonin (BMLT) was evaluated by5 standard methods as follows: 2, 2-diphenyl-1-picrylhydrazyl (DPPH); ferric ion reducing antioxidant power (FRAP); superoxide anion scavenging; nitric oxide (NO) scavenging; and thiobarbituric acid reactive substances (TBARs).Evaluation of cellular antioxidant activity (CAA) and protectivity against H₂O₂ induced cellular damage was performed via MTT assay in HGF cells.

RESULTS

According to the standard anti-oxidant assays, the antioxidant power of AMLT and BMLT were slightly less than MLT in FRAP and superoxide scavenging assays. In the NO scavenging and TBARs assays, BMLT and AMLT were more potent than MLT, whereas DPPH assays demonstrated that MLT was more potent than others. BMLT and AMLT had more potent anti-oxidant and protective activities against H₂O₂in HGF cells as compared with MLT.

CONCLUSIONS

MLT derivatives demonstrated different anti-oxidant activities as compared with MLT, depending upon assays. These findings imply that N-indole substitution of MLT may help to improve hydrogen atom transfer to free radicals but electron transfer property is slightly decreased. Anti-oxidant and protective effects of melatonin derivatives (AMLT and BMLT) on human gingival fibroblasts imply the potential use of these molecules as alternative therapeutics for chronic inflammatory oral diseases.

Total antioxidant status and oxidative stress in recurrent aphthous stomatitis

BACKGROUND

Recurrent aphthous stomatitis is an idiopathic, chronic, recurrent inflammatory disease of the oral mucosa. It is thought that oxidative stress caused by systemic inflammation plays a basic role in the etiopathogenesis of recurrent aphthous stomatitis. The aim of this study is to review oxidative status and DNA damage in recurrent aphthous stomatitis.

METHOD

The study included 42 patients with an active recurrent aphthous stomatitis lesion and 39 healthy volunteers with similar demographic characteristics. DNA damage was analyzed using alkaline single cell gel electrophoresis (comet assay). Plasma levels of total antioxidant status and total oxidative status were determined by using an automated measurement method. Oxidative stress index was calculated as total oxidative status/total antioxidant status and × 100.

RESULTS

The total oxidative status and oxidative stress index values were significantly higher in the recurrent aphthous stomatitis group compared to the control group, while total antioxidant status values were significantly lower. In the recurrent aphthous stomatitis group, DNA damage was observed to be significantly higher than the control group. In correlation analysis, significant correlation was found between DNA damage and the oxidative stress index and total oxidative status values in the recurrent aphthous stomatitis group.

CONCLUSION

This is the first report in the literature that demonstrates association of recurrent aphthous stomatitis with increased oxidative status.