Recurrent Aphthous Stomatitis: An Assessment of Antioxidant Levels in Plasma and Saliva

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 Relationship between the Concentration of Salivary Tyrosine and Antioxidants in Patients with Oral Lichen Planus

The diagnosis of oral lichen planus (OLP) is based on clinical examination and histopathological criteria. Noninvasive diagnostics of saliva may be considered as a confirmation of OLP diagnosis and a potential alternative to an invasive method. The objective of the present study was to evaluate the relationship between the level of tyrosine (Tyr) as well as antioxidants like uric acid (UA) and glutathione peroxidase (GPx) activity in the saliva of patients with OLP in comparison with the control group (healthy subjects without any oral changes). A total of 40 patients with OLP and 40 healthy volunteers were selected for the study based on the modified WHO diagnostic (clinical and histopathological) criteria. High-performance liquid chromatography (HPLC) was performed for Tyr concentration, while GPx activity and uric acid levels were determined by a colorimetric method. The concentrations of Tyr, UA, and GPx activity were statistically lowered in OLP patients compared to the control group. All examined parameters correlated strongly and positively with each other. Mean values of salivary UA concentrations differed between the groups of OLP patients (reticular and erosive forms) and controls (206.66 vs. 196.54 vs. 218.49 μmol/L, respectively, p = 0.001). A similar trend was demonstrated in salivary Tyr concentration which differed statistically between the study and control groups (0.08 vs. 0.07 vs. 0.13 μmol/L, respectively, p = 0.001). Determining of a relationship between the concentrations of Tyr, UA, and GPx activity may be useful in the prognosis of OLP. The HPLC method may be employed, as an additional noninvasive diagnostic procedure to screen OLP patients, during the routine diagnostics of salivary biochemical parameters such as aromatic amino acids.