Antioxidants and biomarkers of oxidative damage in the saliva of patients with Down's syndrome

Salivary Molecular Spectroscopy with Machine Learning Algorithms for a Diagnostic Triage for Amelogenesis Imperfecta

Amelogenesis imperfecta (AI) is a genetic disease characterized by poor formation of tooth enamel. AI occurs due to mutations, especially in AMEL, ENAM, KLK4, MMP20, and FAM83H, associated with changes in matrix proteins, matrix proteases, cell-matrix adhesion proteins, and transport proteins of enamel. Due to the wide variety of phenotypes, the diagnosis of AI is complex, requiring a genetic test to characterize it better. Thus, there is a demand for developing low-cost, noninvasive, and accurate platforms for AI diagnostics. This case-control pilot study aimed to test salivary vibrational modes obtained in attenuated total reflection fourier-transformed infrared (ATR-FTIR) together with machine learning algorithms: linear discriminant analysis (LDA), random forest, and support vector machine (SVM) could be used to discriminate AI from control subjects due to changes in salivary components. The best-performing SVM algorithm discriminates AI better than matched-control subjects with a sensitivity of 100%, specificity of 79%, and accuracy of 88%. The five main vibrational modes with higher feature importance in the Shapley Additive Explanations (SHAP) were 1010 cm-1, 1013 cm-1, 1002 cm-1, 1004 cm-1, and 1011 cm-1 in these best-performing SVM algorithms, suggesting these vibrational modes as a pre-validated salivary infrared spectral area as a potential biomarker for AI screening. In summary, ATR-FTIR spectroscopy and machine learning algorithms can be used on saliva samples to discriminate AI and are further explored as a screening tool.

Gingival Enlargement Associated with Orthodontics Appliance Increases Protein Carbonylation and Alters Phosphorylation of Salivary Proteome

Gingival enlargement is a common clinical sign in the gingival diseases associated with orthodontic treatment. Its biological mechanisms are not completely understood; nevertheless, the biochemical changes associated with these inflammatory and overgrowth processes could alter the post-translational protein modifications occurring in various locations within the mouth. Here, changes in the profiles of the carbonylated and phosphorylated proteins in saliva were examined in donors with gingival enlargement (seven men and seven women) and healthy donors (six men and eight women). The sociodemographic characteristics of both groups did not present significant differences. Carbonylation was measured by a quantitative immunoassay (Dot Blot), whereas the profiles of the phosphorylated proteins were visualized by SDS-PAGE with quercetin staining. Some phosphopeptides were also identified using a typical LC-MS-MS approach. Our results showed that gingival enlargement induced a significant increase in oxidative damage in salivary proteins. While a significant reduction in phosphorylation was observed at the stain level in SDS-PAGE, there was a slight increase in the number of phosphorylated proteins identified by MS in samples with gingival enlargement.

Distinguishable short-term effects of tea and water drinking on human saliva redox

Food consumption can alter the biochemistry and redox status of human saliva, and the serving temperature of food may also play a role. The study aimed to explore the immediate (3 min) and delayed (30 min) effects of hot tea (57 ± 0.5 °C) ingestion and cold tea (8 ± 0.5 °C) ingestion on the salivary flow rate and salivary redox-relevant attributes. The saliva was collected from 20 healthy adults before, 3-min after and 30-min after the tea ingestion. The hot or cold deionised water at the same temperatures were used as control. The salivary flow rate and redox markers in hot tea (HBT), cold tea (CBT), hot water (HW) and cold water (CW) group were analysed and compared. The results demonstrated that neither the black tea nor the water altered the salivary flow rate; the black tea immediately increased the salivary thiol (SH) and malondialdehyde (MDA) content while reduced salivary uric acid (UA) significantly. The tea ingestion showed a tendency to elevate the ferric reducing antioxidant power (FRAP) in saliva, although not significantly. The water ingestion decreased the MDA content immediately and increased the UA level significantly. Cold water was found to induce a greater delayed increase in total salivary total protein (TPC) than the hot water. In conclusion, the black tea ingestion affects the redox attributes of human saliva acutely and significantly, while the temperature of drink makes the secondary contribution.

Comparing the Effectiveness of Octenidine Hydrochloride and Chlorhexidine Gluconate Mouthrinses in Reducing Plaque and Oxidative Stress in Institutionalized Children with Down Syndrome

Background and objectives

Due to decreased manual dexterity, a lack of motivation, and difficulty on the part of the caregiver conducting efficient oral hygiene measures at home, patients with Down syndrome (DS) are badly affected. The objective of this study is to compare the efficacy of 0.1% octenidine (OCT) hydrochloride and 0.12% chlorhexidine (CHX) gluconate on plaque control and oxidative stress in institutionalized children with DS.

Materials and methods

In 20 children, salivary samples were collected for analysis of the inflammatory marker high-sensitive C-reactive protein (hsCRP) and oxidative stress markers, specifically malondialdehyde (MDA). Plaque index (PlI) and gingival index (GI) were scored. After oral prophylaxis, the participants were randomly assigned to two groups, each consisting of 10 individuals (octenidol and CHX). Salivary oxidative stress marker assays were carried out using a modified version of Yagi's (1984) method, and absorbance was measured at 540 nm using an ultraviolet-visible spectrophotometer at 535 nm. hsCRP assays were conducted via latex turbidimetric immunoassay.

Results

On comparison between the two groups, the OCT group showed a statistically significant reduction in GI, PlI, and MDA values (p < 0.05).

Conclusion

It was seen that the use of 0.1% OCT hydrochloride could facilitate the maintenance of good oral hygiene and periodontal status, especially in patients with motor difficulties.

Clinical trial registration

PMS/IEC/2016/02.

How to cite this article

Raj AS, George S, S A, et al. Comparing the Effectiveness of Octenidine Hydrochloride and Chlorhexidine Gluconate Mouthrinses in Reducing Plaque and Oxidative Stress in Institutionalized Children with Down Syndrome. Int J Clin Pediatr Dent 2024;17(4):437-441.

Salivary Malondialdehyde Level as a Lipid Peroxidation Marker in Early Childhood Caries

Background: Early childhood caries (ECC) is an aggressive and multifactorial form of dental caries in children, in which the biomarkers of oxidative stress may increase. Objectives: This study aimed to compare the salivary malondialdehyde (MDA) levels in children with early childhood caries (ECC) and caries-free (CF) children. Methods: To this end, 42 ECC children and 42 CF children, aged 4 - 6 years, were randomly selected from the kindergartens of four socio-economically different districts of Isfahan. An unstimulated saliva sample was obtained from children fasting during the past night using the spitting method. In the laboratory, the MDA levels were evaluated spectrophotometrically. An independent-samples t-test was used to examine the differences between the two groups. Results: The mean salivary MDA level was significantly higher in the ECC group than in the CF group (P = 0.01), and there was no significant relationship between salivary MDA and gender (P = 0.44 in the ECC group, P = 0.30 in the CF group). Moreover, no significant relationship was noticed between MDA with decayed, missing, filled teeth (dmft). Conclusions: The findings documented a relationship between ECC and MDA as one of the products of oxidative stress reactions. Accordingly, the MDA level of saliva can be a critical indicator in determining the status of caries in children.

Peripheral Oxidation Markers in Down Syndrome Patients: The Better and the Worse

Oxidative stress plays an important role in Down syndrome (DS) pathology since the gene dose effect leads to abnormal levels of certain enzymes and metabolites. In this review, we focused on relatively easy-to-obtain, peripheral markers of oxidative stress and inflammation, in order to compare the levels of these markers in DS patients and chromosomally healthy persons. Studies taking into account age- and sex-matched control groups were of particular interest in this context. We analyzed the factors that influence the levels of said markers in both groups (i.e., the usefulness of the markers), including the age of DS patients, occurrence of regular trisomy 21 or mosaicism, physical activity of patients, and the onset of Alzheimer's disease in DS. This paper was conceived as a handbook-to help for selecting suitable, easy-to-obtain markers for monitoring of the health status of DS patients (e.g., in nutritional studies and during dietary supplementation).

Effect of cerebral palsy and dental caries on dental plaque index, salivary parameters and oxidative stress in children and adolescents

PURPOSE

The aim of the present study was to investigate the effect of cerebral palsy and dental caries on dental plaque index, salivary parameters and oxidative stress in children and adolescents.

METHODS

Seventy children and adolescents aged 2-20 years were divided into four groups: neurotypical controls-inactive caries (NCIC; n = 19); neurotypical controls-active caries (NCAC; n = 16); cerebral palsy-inactive caries (CPIC; n = 19); and cerebral palsy-active caries (CPAC; n = 16). The visible dental plaque index was determined after drying the tooth surfaces and without any mechanical or chemical disclosing methods. Salivary pH and buffer capacity were measured 1 hour after collection using a digital pH meter. Saliva was used to evaluate oxidative status based on the levels of reactive species, lipid peroxidation and non-enzymatic antioxidants (reduced glutathione and vitamin C).

RESULTS

The CPIC and CPAC groups had lower salivary pH and a higher visible dental plaque index. CP was also associated with an increase in salivary levels of markers of oxidative stress and the modulation of salivary levels of non-enzymatic antioxidants.

CONCLUSION

Cerebral palsy exerts an influence on the salivary profile, oral health and oxidative stress. The individuals with CP had more acidic saliva and a higher dental plaque index, which were positively correlated with caries activity. CP was associated with high salivary levels of reactive species and lipid peroxidation, demonstrating an imbalance in salivary redox that was particularly associated with caries activity. These factors facilitate the development of oral diseases in individuals with cerebral palsy.

Meta-analysis of metabolites involved in bioenergetic pathways reveals a pseudohypoxic state in Down syndrome

Clinical observations and preclinical studies both suggest that Down syndrome (DS) may be associated with significant metabolic and bioenergetic alterations. However, the relevant scientific literature has not yet been systematically reviewed. The aim of the current study was to conduct a meta-analysis of metabolites involved in bioenergetics pathways in DS to conclusively determine the difference between DS and control subjects. We discuss these findings and their potential relevance in the context of pathogenesis and experimental therapy of DS. Articles published before July 1, 2020, were identified by using the search terms “Down syndrome” and “metabolite name” or “trisomy 21” and “metabolite name”. Moreover, DS-related metabolomics studies and bioenergetics literature were also reviewed. 41 published reports and associated databases were identified, from which the descriptive information and the relevant metabolomic parameters were extracted and analyzed. Mixed effect model revealed the following changes in DS: significantly decreased ATP, CoQ10, homocysteine, serine, arginine and tyrosine; slightly decreased ADP; significantly increased uric acid, succinate, lactate and cysteine; slightly increased phosphate, pyruvate and citrate. However, the concentrations of AMP, 2,3-diphosphoglycerate, glucose, and glutamine were comparable in the DS vs. control populations. We conclude that cells of subjects with DS are in a pseudo-hypoxic state: the cellular metabolic and bio-energetic mechanisms exhibit pathophysiological alterations that resemble the cellular responses associated with hypoxia, even though the supply of the cells with oxygen is not disrupted. This fundamental alteration may be, at least in part, responsible for a variety of functional deficits associated with DS, including reduced exercise difference, impaired neurocognitive status and neurodegeneration.

Evaluation of the masticatory biomechanical function in Down syndrome and its Influence on sleep disorders, body adiposity and salivary parameters

OBJECTIVE

To evaluate the phenotypic features of the masticatory biomechanics in atypical subjects with Down syndrome (DS). Its influence was analysed on sleep disorders, body adiposity and its risks, and some physicochemical properties of saliva.

METHODS

Seventy subjects were enrolled to assess masticatory biomechanical function and divided into two groups: DS and control groups. Electrical activities of the masseter and temporal muscles (at rest and in maximum voluntary clench-MVC), maximum bite force-MBF and maximum mouth opening-MMO were investigated. Among the atypical subjects, just 24 participants underwent the anthropometry, the polysomnography II and the saliva testing (salivary flow rate-SFR, buffer capacity-BC and salivary cortisol levels, morning/SC-AM and night/SC-PM).

RESULTS

MVC and MBF values showed high statistical significance in the control group (P < .001) than in the DS group of 35. MMO values were slightly increased in the DS group in relation to the control group. Overweight and obesity were found in both genders. Atypical women showed higher risk to develop cardiovascular-metabolic diseases than in atypical men. OSA severe was 20% for atypical women and 42.8% for atypical men, whereas snoring index was present in all genders. SFR was reduced in 100% of atypical subjects (hyposalivation in 10% women and 28.5% men). Furthermore, 100% BC, 66.6% SC-AM and 91.6% SC-PM showed normal patterns.

CONCLUSION

Masseter and temporal muscle hypotonia was found in all atypical subjects with DS. This muscle dysfunction strongly was related to overweight/obesity, risks for development of cardiovascular/metabolic diseases, OSA severity, successive snoring episodes and salivary flow reduction in DS.

Evaluation of enzymatic and non-enzymatic antioxidant status and biomarkers of oxidative stress in saliva of patients with oral squamous cell carcinoma and oral leukoplakia: a pilot study

Objective: The study aimed to evaluate total antioxidant capacity as well as levels of various enzymatic and non-enzymatic antioxidants, and oxidative stress markers in saliva of patients with oral squamous cell carcinoma (OSCC) and oral leukoplakia (OL). Material and methods: Twenty patients with OSCC, 20 patients with OL and 20 healthy subjects were enrolled into this prospective study. Total Antioxidant Capacity (TAC), activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) as well as levels of total glutathione (tGSH), reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/GSSG ratio, uric acid (UA), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were estimated in saliva using appropriate biochemical methods. Results: The activity of SOD was significantly higher in OSCC group in comparison with OL and control groups. The levels of GSH were markedly lower in OSCC and OL patients as compared to the control group. Likewise, we found that GSH/GSSG ratio was markedly lower in the OSCC and OL groups. Levels of some biomarkers were influenced by clinical staging of OSCC and OL as well as by sociodemographic factors. Conclusions: The results of this pilot study suggest that salivary activity of SOD is higher in OSCC patients, whereas levels of GSH and GSH/GSSG ratio are lower in saliva of patients with OSCC and OL. Clinical staging of OSCC and OL, as well as some sociodemographic factors may also influence salivary antioxidant status.

A cross sectional study to evaluate the oral health status of children with intellectual disabilities in the National Capital Region of India (Delhi-NCR)

BACKGROUND

Children with intellectual disabilities (ID) have usually been reported to have poorer levels of oral hygiene and higher prevalence of dental caries than their compeers. The present study was conducted to assess the status of dental caries and oral hygiene in different categories of institutionalised children with ID (syndromic and non-syndromic) registered in various special schools of Delhi (National Capital Region, India).

METHODS

The present cross sectional study was conducted on 269 children [52 with cerebral palsy (CP), 35 with Down syndrome (DS), 30 with autism and 152 with non-syndromic intellectual disability] attending nine special schools who were examined for dental caries [Decayed, Missing and Filled Teeth index for permanent teeth (DMFT); decayed, missing/indicated for extraction, filled index for primary teeth (dmft) and prevalence of caries] and oral hygiene status [Oral Hygiene Index-simplified (OHI-S)]. The levels of disability were classified according to Stanford Binet scale as severe (IQ ≤ 35), moderate (IQ = 36-51) and mild (IQ = 52-67). Statistical analysis was performed using one way analysis of variance and post hoc test to compare the levels between groups at a significance level of P < 0.05.

RESULTS

Mean DMFT, dmft and OHI-S indices scores for all the children irrespective of the category and the level of ID were 2.12 ± 1.95, 0.97 ± 1.60 and 2.05 ± 1.07, respectively. As the level of ID increased among these children, the mean DMFT index and OHI-S index increased with no significant effect on dmft. However, children with severe ID had higher OHI-S and DMFT scores than children with mild or moderate ID. The dental caries prevalence was 86.53%, 68.57%, 76% and 86.18% in children with CP, DS, autism and non-syndromic intellectual disability, respectively.

CONCLUSIONS

The level of caries in permanent teeth and oral hygiene deteriorated with the increasing severity of ID as indicated by DMFT and OHI-S scores (severe > mild, moderate). However, the level of caries (dmft) was not affected by the level of ID in primary dentition. The prevalence of dental caries was highest among children with CP and least among children with DS.

Antioxidant capacity and biomarkers of oxidative stress in saliva of khat-chewing patients: a case-control study

OBJECTIVES

The aim of this study was to investigate the antioxidant levels and biomarkers of oxidative stress in saliva from khat-chewing patients compared with controls.

STUDY DESIGN

Saliva samples were collected from 51 chronic khat chewers and 46 age- and sex-matched controls. Concentrations of oxidative stress biomarkers (malonyl-dialdehyde [MDA], protein carbonyl, and 8-hydroxy-2'-deoxyguanosine) and antioxidant defense (total antioxidant capacity [TAC], superoxide dismutase, glutathione peroxidase, and catalase [CAT) were analyzed.

RESULTS

Salivary MDA level in the khat users group (45 ± 9.2 nmol/mL) was significantly increased in comparison with controls (13 ± 2.1 nmol/mL; P < .001), but there were no significant differences between the 2 groups regarding the levels of salivary protein carbonyl and oxidized guanine species. Salivary TAC was significantly reduced in khat users (0.25 ± 0.028 mmol/L) in comparison with controls (0.34 ± 0.037 mmol/L). Salivary CAT level was significantly reduced in khat users (6.0 ± 0.47 U/mL) in comparison with controls (7.7 ± 0.43 units/mL; P <.05), but no significant differences were observed between the 2 groups with regard to salivary superoxide dismutase or glutathione peroxidase levels.

CONCLUSIONS

Chronic khat chewing is associated with increased levels of salivary MDA and reduced levels of TAC and CAT among a population of adult men in comparison with non-khat-chewing controls. These findings suggest that the pro-oxidative effect of khat chewing may be a contributing mechanism for various oral diseases associated with khat use, including cancer, periodontitis, and caries.

The Dental Needs and Treatment of Patients with Down Syndrome

Down syndrome is a common disorder with many oral conditions and systemic manifestations. Dentists need to take a holistic approach including behavioral, oral, and systemic issues. This review of the literature focuses on oral anomalies, systemic interaction, management, and recommendations.

Reduced salivary flow rate and high levels of oxidative stress in whole saliva of children with Down syndrome

AIM

To investigate salivary parameters between children with Down Syndrome (DS) and without DS.

MATERIALS AND METHODS

Stimulated whole saliva was collected from 18 children with DS and 23 without DS. Salivary flow rate, pH, and salivary buffering capacity were determined. Cariogenic microorganisms were quantified by culture, and periodontopathogens by quantitative real-time polymerase chain reaction. The antioxidant profile was quantified spectrophotometrically, while malondialdehyde (MDA) was quantified by high-performance liquid chromatography. Data were analyzed by Mann-Whitney test and Spearman correlation (α = 0.05).

RESULTS

Salivary flow rate was significantly lower in DS than in controls (p < 0.0001). Significant higher difference was observed for total protein dosage (p < 0.0001), superoxide dismutase activity (SOD) (p = 0.0002), and MDA (p < 0.001) in DS group.

CONCLUSIONS

Reduced salivary flow rate might be an important factor in oral diseases development. High salivary levels of SOD and MDA show the significant influence of the oxidative stress and the early-onset periodontal disease in DS people.

Systematic review and meta-analysis shows a specific micronutrient profile in people with Down Syndrome: Lower blood calcium, selenium and zinc, higher red blood cell copper and zinc, and higher salivary calcium and sodium

Different metabolic profiles as well as comorbidities are common in people with Down Syndrome (DS). Therefore it is relevant to know whether micronutrient levels in people with DS are also different. This systematic review was designed to review the literature on micronutrient levels in people with DS compared to age and sex-matched controls without DS. We identified sixty nine studies from January 1967 to April 2016 through main electronic medical databases PubMed, Scopus, and Web of knowledge. We carried out meta-analysis of the data on four essential trace elements (Cu, Fe, Se, and Zn), six minerals (Ca, Cl, K, Mg, Na, and P), and five vitamins (vitamin A, B9, B12, D, and E). People with DS showed lower blood levels of Ca (standard mean difference (SMD) = -0.63; 95% confidence interval (CI): -1.16 to -0.09), Se (SMD = -0.99; 95% CI: -1.55 to -0.43), and Zn (SMD = -1.30; 95% CI: -1.75 to -0.84), while red cell levels of Zn (SMD = 1.88; 95% CI: 0.48 to 3.28) and Cu (SMD = 2.77; 95% CI: 1.96 to 3.57) were higher. They had also higher salivary levels of Ca (SMD = 0.85; 95% CI: 0.38 to 1.33) and Na (SMD = 1.04; 95% CI: 0.39 to 1.69). Our findings that micronutrient levels are different in people with DS raise the question whether these differences are related to the different metabolic profiles, the common comorbidities or merely reflect DS.

Vitamin C: the known and the unknown and Goldilocks

Vitamin C (Ascorbic Acid), the antiscorbutic vitamin, cannot be synthesized by humans and other primates, and has to be obtained from diet. Ascorbic acid is an electron donor and acts as a cofactor for fifteen mammalian enzymes. Two sodium-dependent transporters are specific for ascorbic acid, and its oxidation product dehydroascorbic acid is transported by glucose transporters. Ascorbic acid is differentially accumulated by most tissues and body fluids. Plasma and tissue vitamin C concentrations are dependent on amount consumed, bioavailability, renal excretion, and utilization. To be biologically meaningful or to be clinically relevant, in vitro and in vivo studies of vitamin C actions have to take into account physiologic concentrations of the vitamin. In this paper, we review vitamin C physiology; the many phenomena involving vitamin C where new knowledge has accrued or where understanding remains limited; raise questions about the vitamin that remain to be answered; and explore lines of investigations that are likely to be fruitful.

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.

Salivary markers of oxidative stress in oral diseases

Saliva is an interesting alternative diagnostic body fluid with several specific advantages over blood. These include non-invasive and easy collection and related possibility to do repeated sampling. One of the obstacles that hinders the wider use of saliva for diagnosis and monitoring of systemic diseases is its composition, which is affected by local oral status. However, this issue makes saliva very interesting for clinical biochemistry of oral diseases. Periodontitis, caries, oral precancerosis, and other local oral pathologies are associated with oxidative stress. Several markers of lipid peroxidation, protein oxidation and DNA damage induced by reactive oxygen species can be measured in saliva. Clinical studies have shown an association with oral pathologies at least for some of the established salivary markers of oxidative stress. This association is currently limited to the population level and none of the widely used markers can be applied for individual diagnostics. Oxidative stress seems to be of local oral origin, but it is currently unclear whether it is caused by an overproduction of reactive oxygen species due to inflammation or by the lack of antioxidants. Interventional studies, both, in experimental animals as well as humans indicate that antioxidant treatment could prevent or slow-down the progress of periodontitis. This makes the potential clinical use of salivary markers of oxidative stress even more attractive. This review summarizes basic information on the most commonly used salivary markers of oxidative damage, antioxidant status, and carbonyl stress and the studies analyzing these markers in patients with caries or periodontitis.