Aphthous ulcers, salivary peroxidase and stress: Are they related?

Detection and Analysis of the Oral Flora in Patients with Recurrent Aphthous Stomatitis

The present study detected differences in the oral mucosal flora in healthy people and patients diagnosed with recurrent aphthous stomatitis (RAS) using the 16S ribosomal RNA high-throughput sequencing (rRNA-seq). All samples were collected from the lower lip mucosa of 100 healthy individuals and 100 patients with RAS. After the extraction, DNA was subjected to PCR amplification for the bacterial 16S rRNA gene, before subjecting to high-throughput sequencing, and matched to a database. Most bacterial species and most unique bacteria were from the healthy control group, and the amount of operational taxonomic units (OTUs) calculated was similar in the ulcer and nonulcer sites. Firmicutes, Proteobacteria, and Bacteroidetes were most abundant in the healthy group and in ulcer, nonulcer, and healed ulcer sites at the phylum level. Meanwhile, the number of Prevotella was significantly elevated in ulcer sites (P < 0.05). Healthy people had more species of bacteria inhabiting their oral mucosa than did RAS patients, and patients with ulcers had the lowest abundance of bacterial species. We suggest that the number of Prevotella is associated with RAS.

Clustering of Signs and Symptoms of Oral Diseases in a Colombian Population

OBJECTIVE

The aim of this study was to estimate disease pattern clusters and co-occurrences of oral signs and symptoms in a Colombian population.

METHODS

A cross-sectional study was carried out through a telephone survey amongst 1155 people registered in the telephone directory from Pasto, Colombia. The calls were made from July to November 2019. A 14-item self-report questionnaire about signs and symptoms related to oral diseases that included sociodemographic characteristics was employed. Descriptive and multivariable analyses such as hierarchical clustering, multidimensional scaling, and generalized linear models were used to determine co-occurrences in different sex and age strata.

RESULTS

Age- and condition-specific clusters of signs and symptoms were identified, while sex differences were limited. Calculus and denture sore mouth were related in 18- to 34-year-olds; tooth loss and calculus in 35- to 54-year-olds, and teeth holes or pits (dental caries) and dental abscess in those aged 55 years and older. We found stronger associations between periodontal disease (bleeding gums) and dental caries (odds ratio [OR], 2.484; 95% confidence interval [CI], 1.812-3.405; P < .001) as well as grinding/clenching and facial tension (OR, 7.162; 95% CI, 5.227-9.814; P < .001).

CONCLUSIONS

Age-specific clustering of signs and symptoms and diagnostic patterns wer present in ths Colombian cohort.

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

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

Redox Regulation of Inflammatory Processes Is Enzymatically Controlled

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

Assessment of Oxidant-Antioxidant Status and Stress Factor in Recurrent Aphthous Stomatitis Patients: Case Control Study

INTRODUCTION

Despite its vast occurrence, the aetiology of Recurrent Aphthous Stomatitis (RAS) still remains unknown and its aetiology is multifactorial. The factors believed to be associated with the aetiology of RAS, may disturb the equilibrium of oxidant-antioxidant status of the organism and may accelerate the formation of free radicals, resulting in Oxidative Stress (OS). Psychological stress is believed to act as a triggering factor or modifying factor for RAS.

AIM

To find whether oxidant-antioxidant status and psychosocial stress play a role in the pathogenesis of RAS.

MATERIALS AND METHODS

The study was conducted on 60 subjects over a period of one year (August 2014-August 2015) equally divided into two groups-patients with RAS and healthy controls. Psychosocial stress was analyzed by using Recent Life Changes Questionnaire (RLCQ). Saliva was analyzed to evaluate Superoxide Dismutase (SOD) and Glutathione Peroxidase (GSHPx) activities, Malondialdehyde (MDA) and Uric Acid (UA) levels in both the study and the control groups, using UV spectrophotometry.

RESULTS

The mean value of salivary SOD and MDA was increased while the activity of GSHPx and UA decreased in the study group when compared to the controls; the difference being statistically significant (p<0.005). The mean RLCQ stress score was also found to be increased in the RAS group, which showed elevated levels of mental stresses when compared to physical stresses. No significant association was observed between SOD, MDA, GSHPx and UA with high levels of stress score (p>0.05). In the study group, no correlation was observed between the study variables and gender, the number of ulcer episodes in one year, the number of ulcers per episode or the duration of ulcers.

CONCLUSION

This study shows that salivary antioxidant levels show a significant difference in response to OS in RAS patients. An increase in levels of psychosocial stress is seen associated with patients with RAS indicating its role as a modifying or triggering factor in the initiation of RAS.