Periodontitis, diabetes mellitus, and the lopsided redox balance: A unifying axis

Redox biomarkers in saliva and nuclear abnormalities in jugal epithelial cells of individuals with type 2 diabetes mellitus and periodontitis

OBJECTIVE

To evaluate salivary redox biomarkers levels in individuals with periodontitis and type 2 diabetes mellitus (T2DM) and correlate with periodontal parameters and nuclear alterations in epithelial cells from jugal mucosa.

DESIGN

Sixty individuals were categorized into three groups: T2DM with periodontitis (DM, n = 20), non-T2DM with periodontitis (PE, n = 20), and non-T2DM with periodontal health (HC, n = 20). All participants underwent fasting blood glucose and glycated hemoglobin measurements. After a periodontal examination, samples of epithelial cells from the jugal mucosa and saliva were collected. DNA damage was assessed by counting nuclear abnormalities using cytological analysis. Biomarkers of oxidative stress were determined through biochemical methods. Significant differences among groups were assessed using Kruskal-Wallis, Mann-Whitney, and Chi-square tests at a 5% significance level. Data were analyzed using Spearman's correlation coefficient, linear regression, and logistic regression.

RESULTS

Frequencies of nuclear abnormalities, as well as levels of reduced glutathione and uric acid, were significantly higher in the DM group compared to the PE and HC groups (p < 0.05). Fasting glucose, glycated hemoglobin, nuclear abnormalities, reduced glutathione, and uric acid exhibited positive correlations with periodontal parameters (p < 0.05). Furthermore, reduced glutathione was associated with dental biofilm (OR = 1.027 [95% CI, 1.004-1.049]) and condensed chromatin (OR = 0.415 [95% CI, 0.196-0.878]).

CONCLUSIONS

Periodontitis and T2DM are correlated with nuclear abnormalities, as well as salivary reduced glutathione and uric acid levels. Moreover, a higher prevalence of teeth with dental biofilm increases the likelihood of elevated levels of reduced glutathione in saliva, while the presence of condensed chromatin decreases that likelihood.

Oxidative Stress and Antioxidant System in Periodontitis

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

Assessment of salivary total antioxidant capacity in patients with primary untreated head and neck squamous cell carcinoma with ORAC

BACKGROUND

Oxidative DNA damage leads to abnormalities in endogenous cellular processes and constitutes a direct link between free radicals, antioxidants and squamous cell carcinoma (SCC). Oxygen radical absorbance capacity (ORAC) method is used to measure antioxidant capacity versus oxygen free radicals. There is no report on the application of ORAC to evaluate salivary antioxidant capacity in patients with head and neck SCC. This study investigated the relation between total antioxidant capacity of saliva, measured with ORAC method, and the incidence, location, size and histopathological grading of SCC.

METHODS

Salivary antioxidant capacity was assessed in 30 male and female patients with histopathologically confirmed oral and laryngeal SCC. Histopathological grading of SCC was based on WHO classification.

RESULTS

Mean ORAC in patients with SCC was higher than the mean value in the control group. Statistically significant difference was observed in the study group versus the control group. No significant differences were observed for ORAC values in relation to histopathological grading, tumour size and spread to lymph nodes.

CONCLUSIONS

The obtained results can advocate local compensatory mechanism in saliva in response to increased oxidative stress associated with primary tumour. ORAC can become an additional factor in head and neck SCC prognosis, but further investigation is required.

Salivary and Urinary Total Antioxidant Capacity as Biomarkers of Oxidative Stress in Humans

Total Antioxidant Capacity (TAC) is a biomarker often used in order to investigate oxidative stress in many pathological conditions. Saliva and urine can be collected noninvasively and represent attractive diagnostic fluids for detecting biomarkers of various pathological conditions. The reviewed case-control and intervention studies that measured salivary or urinary TAC revealed that diseases, antioxidant foods, or supplements and age, gender, and lifestyle factors influenced salivary or urinary TAC. Salivary and urinary TAC were particularly affected by oral or renal status, respectively, as well as by infection; therefore these factors must be taken into account in both case-control and intervention studies. Furthermore, some considerations on sample collection and normalization strategies could be made. In particular, unstimulated saliva could be the better approach to measure salivary TAC, whereas 24 h or spontaneous urine collection should be chosen on the basis of the study outcome and of the creatinine clearance. Finally, the uric acid-independent TAC could be the better approach to evaluate red-ox status of body, in particular after nutritional interventions and in diseases associated with hyperuricaemia.