Children with a Higher Activity of Carbonic Anhydrase VI in Saliva Are More Likely to Develop Dental Caries

Sucrose rinse modulates the salivary behavior of carbonic anhydrase VI and its buffering capacity: a longitudinal study in 4 to 6.5-year-old children

Background

Carbonic anhydrase VI (CA VI) is crucial in regulating oral pH and predicting susceptibility to dental caries. The hypothesis posits that caries activity may alter the CA VI function, diminishing its capacity to regulate pH effectively and potentially exacerbating cariogenic challenges. This 1-year cohort study sought to investigate the enzymatic activity of salivary CA VI and buffering capacity following a 20% sucrose rinse in 4 to 6.5-year-old children.

Method

This research involved 46 volunteers categorized into three groups based on their caries status after follow-up: caries-free (CFee), arrested caries (CArrested), and caries active (CActive). Children underwent visible biofilm examination and saliva collection for salivary flow rate, buffering capacity, and CA VI analyses before and after a 20% sucrose rinse.

Results

A reduction in the buffering capacity was observed after sucrose rinse in all groups. The CA VI activity decreased significantly in CFee and CArrested groups after sucrose rinse, although it did not change in the CActive group. An improvement in the buffering capacity and salivary flow rate was found at follow-up when compared with the baseline. After 1-year follow-up, buffering capacity and salivary flow rate increased in all groups, whilst the CA VI activity reduced only in CFree and CArrested children.

Conclusion

Sucrose rinse universally reduces the salivary buffering capacity, while caries activity may disrupt CA VI activity response during a cariogenic challenge. After a year, increased salivary flow enhances buffering capacity but not CA VI activity in caries-active children.

Herbal Metabolites as Potential Carbonic Anhydrase Inhibitors: Promising Compounds for Cancer and Metabolic Disorders

Background

Human carbonic anhydrases (CAs) play a role in various pathological mechanisms by controlling intracellular and extracellular pH balance. Irregular expression and function of CAs have been associated with multiple human diseases, such as obesity, cancer, glaucoma, and epilepsy. In this work, we identify herbal compounds that are potential inhibitors of CA VI.

Methods

We used the AutoDock tool to evaluate binding affinity between the CA VI active site and 79 metabolites derived from flavonoids, anthraquinones, or cinnamic acids. Compounds ranked at the top were chosen for molecular dynamics (MD) simulations. Interactions between the best CA VI inhibitors and residues within the CA VI active site were examined before and after MD analysis. Additionally, the effects of the most potent CA VI inhibitor on cell viability were ascertained in vitro through the 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.

Results

Kaempferol 3-rutinoside-4-glucoside, orientin, kaempferol 3-rutinoside-7-sophoroside, cynarin, and chlorogenic acid were estimated to establish binding with the CA VI catalytic domain at the picomolar scale. The range of root mean square deviations for CA VI complexes with kaempferol 3-rutinoside-4-glucoside, aloe-emodin 8-glucoside, and cynarin was 1.37 to 2.05, 1.25 to 1.85, and 1.07 to 1.54 Å, respectively. The MTT assay results demonstrated that cynarin had a substantial effect on HCT-116 cell viability.

Conclusion

This study identified several herbal compounds that could be potential drug candidates for inhibiting CA VI.

Comparison of oral cavity protein abundance among caries-free and caries-affected individuals-a systematic review and meta-analysis

Objective

Some salivary proteins seem to be differently abundant among caries-free (CF) and caries-affected (CA) individuals, but previous results are contradictory precluding that definitive conclusion be drawn. A pooled analysis of the available evidence may provide more robust data on identifying oral cavity protein patterns among CF and CA individuals. This systematic review and meta-analysis (PROSPERO CRD42021269079) aimed to compare the oral cavity protein abundance among caries-free and caries-affected individuals.

Methods

This study was conducted following PRISMA guidelines. PubMed, Embase, and Web of Science databases were systematically assessed (up to February 2023) to retrieve clinical studies written in English, German, or in Latin-based languages that compared the oral cavity protein abundance among CF and CA individuals. Data extraction and methodological quality assessment (NIH guidelines) were independently performed by two investigators. Qualitative synthesis was performed from all included studies and meta-analysis was performed using a random-effects model with inverse variance for studies that reported the concentration of proteins or enzymatic activity. Standardized mean difference (SMD) with respective 95% confidence interval (CI) were calculated for each outcome.

Results

A total of 90 studies (two cohort and 88 cross-sectional designs) of more than 6,000 participants were selected for data extraction, being the quality of evidence graded as "fair" for most of them. The oral cavity of CF individuals presented lower total protein concentration [SMD = 0.37 (95% CI: 0.07-0.68; 18 studies)], lower total antioxidant capacity [SMD = 1.29 (95% CI: 0.74-1.85); 17 studies], and lower carbonic anhydrase activity [SMD = 0.83 (95% CI: 0.58-1.09); three studies], whereas CA individuals presented lower carbonic anhydrase concentration [SMD = -0.66 (95% CI: -1.00 to -0.32); three studies], urease [SMD = -0.95 (IC 95%: -1.72 to -0.17); four studies], and arginine deiminase system [SMD = -2.07 (95% CI: -3.53 to -0.62); three studies] activities. Antimicrobial peptides, secretory immunoglobulin-A concentrations and alpha-amylase activity were similar among individuals.

Conclusion

Differences on oral cavity protein abundance were observed among CF and CA individuals. These data indicate some protein patterns for the oral health and dental caries conditions. Even when statistically significant, some of the results were not very consistent. Cohort studies need to be conducted to validate these results.

Associations of the activity and concentration of carbonic anhydrase VI with susceptibility to dental caries: A systematic review and meta-analysis

OBJECTIVES

A number of studies have claimed that carbonic anhydrase VI (CA VI) is associated with dental caries. The aim of this systematic review and meta-analysis was to systematically review and analyze the literature on the association of CA VI (in terms of concentration and activity) with dental caries.

MATERIALS AND METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant search terms were employed to search the following databases: PubMed, Web of Science, Scopus, China National Knowledge Infrastructure (CNKI), and Cochrane Library databases. Eligible publications from inception to August 2022 were included. The relevant records were assessed independently by two reviewers, and a meta-analysis was performed using RevMan 5.3.

RESULTS

Out of 237 relevant records from the initial search, 9 met the criteria for this review. The 9 papers, including 477 participants, were qualitatively analyzed. Seven studies with 411 participants (203 caries-free) were included in the meta-analysis on CA VI activity, and 2 studies with 141 participants (71 caries-free) were included in the meta-analysis on CA VI concentration. The results showed that CA VI activity was significantly higher among participants with caries than their caries-free counterparts (standardized mean difference (SMD) = 0.894, 95% confidence interval (CI_95% ): 0.386 and 1.392; p < 0.001), whereas the CA VI concentration was significantly lower among participants with caries than their caries-free counterparts (SMD = -0.672, CI_95% : -1.011 and -0.332; p < 0.001).

CONCLUSIONS

This meta-analysis of a relatively small number of studies suggests that the CA VI concentration is lower and CA VI activity is higher in patients with dental caries than in caries-free individuals; however, further studies are needed to determine the exact role of CA VI in dental caries.

Role of Salivary Biomarkers in Diagnosis and Detection of Dental Caries: A Systematic Review

Saliva plays a significant role in oral health and tooth integrity. Salivary components reduce tooth surface exposure to demineralization, protect against teeth wear and aid in enamel remineralization. There is a growing attempt to use salivary markers in diagnosing or predicting caries. However, despite the current information, there has yet to be an agreement among scholars. This study seeks to contribute more evidence on the suitability of salivary biomarkers in dental caries diagnosis. Eligible studies were electronically searched on online databases PubMed, Elsevier's Scopus, EMBASE and Web of Science, and all the studies that met the inclusion criteria were considered. The PECOS criteria guided the study selection process based on the study question. The risk of bias was assessed using the STROBE checklist. Eighteen articles were included in the analysis. All the studies presented relevant data concerning the study objectives. There was evidence of associations between salivary biomarkers and dental caries, and the correlations were either positive or negative. The studies presented significant heterogeneity; thus, a meta-analysis was not possible. Salivary biomarkers appeared to perform crucial and complementary functions toward tooth integrity and thus may be reliable in predicting or diagnosing dental caries in patients.

A Fresh Look at Mouthwashes-What Is Inside and What Is It For?

Mouthwashes are a very popular additional oral hygiene element and there are plenty of individual products, whose compositions are in a state of flux. The aim of our study was to investigate the compositions of mouthwashes and their functions, as well as to discuss their effectiveness in preventing and curing oral diseases and side effects. We searched for mouthwashes available on the market in Poland. We identified 241 individual mouthwash products. The extraction of compositions was performed and functions of the ingredients were assessed. Then, analysis was performed. The evaluation revealed that there are plenty of ingredients, but a typical mouthwash is a water-glycerine mixture and consists of additional sweetener, surfactant, preservative, and some colourant and flavouring agent, as well as usually having two oral health substances, anticaries sodium fluoride and antimicrobial essential oils. The effectiveness or side effects of several substances of mouthwashes were thoroughly discussed. We recommend not multiplying individual mouthwash products and their ingredients beyond medical or pharmaceutical necessity, especially without scientific proof.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Genome-Wide Association Study (GWAS) of dental caries in diverse populations

BACKGROUND

Dental caries is one of the most common chronic diseases and is influenced by a complex interplay of genetic and environmental factors. Most previous genetic studies of caries have focused on identifying genes that contribute to dental caries in specific ethnic groups, usually of European descent.

METHODS

The aim of this study is to conduct a genome-wide association study (GWAS) to identify associations affecting susceptibility to caries in a large multiethnic population from Argentina, the Philippines, Guatemala, Hungary, and the USA, originally recruited for studies of orofacial clefts (POFC, N = 3686). Ages of the participants ranged from 2 to 12 years for analysis of the primary dentition, and 18-60 years for analysis of the permanent dentition. For each participant, dental caries was assessed by counts of decayed and filled teeth (dft/DFT) and genetic variants (single nucleotide polymorphisms, SNPs) were genotyped or imputed across the entire genome. Caries was analyzed separately for the primary and permanent dentitions, with age, gender, and presence/absence of any type of OFC treated as covariates. Efficient Mixed-Model Association eXpedited (EMMAX) was used to test genetic association, while simultaneously accounting for relatedness and stratification.

RESULTS

We identified several suggestive loci (5 × 10-8 < P < 5 × 10-6) within or near genes with plausible biological roles for dental caries, including a cluster of taste receptor genes (TAS2R38, TAS2R3, TAS2R4, TASR25) on chromosome 7 for the permanent dentition analysis, and DLX3 and DLX4 on chromosome 17 for the primary dentition analysis. Genome-wide significant results were seen with SNPs in the primary dentition only; however, none of the identified genes near these variants have known roles in cariogenesis.

CONCLUSION

The results of this study warrant further investigation and may lead to a better understanding of cariogenesis in diverse populations, and help to improve dental caries prediction, prevention, and/or treatment in future.

Carbonic anhydrase VI activity in saliva and biofilm can predict early childhood caries: A preliminary study

AIM

This study aimed to investigate whether carbonic anhydrase VI activity (CA VI_ACT ), pH, and buffering capacity (BC) in saliva and biofilm could predict the number of lesion occurrence and early childhood caries (ECC).

DESIGN

A cross-sectional study was performed in a sample of 44 children aged 4 to 5 years who were examined regarding their caries status (dmfs + active white spot lesions-WSL) and allocated into two groups: ECC and caries-free (CF). Saliva and biofilm were collected to determine pH, BC, and CA VI_ACT . Data were analyzed using the Student t test, and multiple linear regression and logistic regression analyses followed by the ROC curve.

RESULTS

Children with ECC exhibited lower pH and BC in saliva and a higher CA VI_ACT in both saliva and biofilm. Only saliva pH could predict the dmfs + active WSL. In biofilm, if CA VI_ACT is increased by one pixel/µg, 0.85 ± 0.28 increase is expected in the number of active WSL. Salivary pH and CA VI_ACT in saliva and biofilm had the power to predict ECC occurrence.

CONCLUSION

Changes in saliva pH and CA VI_ACT in biofilm predicted the number of lesion occurrence. Furthermore, CA VI_ACT in both saliva and biofilm can predict propensity for ECC.

The role of mechanical control of biofilm in the salivary pH after sucrose exposure in children with early childhood caries

This quasi-experimental study sought to investigate if the mechanical control of biofilm (3-times-a-day) modifies the saliva’s ability to buffer the oral environment after 20% sucrose rinse (SR_20%) in children with early childhood caries (ECC). Here, SR_20% reduced the saliva’s pH in both groups and the mechanical control of biofilm had a greater effect on this parameter after SR_20% in CF children. The mechanical control of biofilm evidenced a higher buffering capacity in CF children before SR_20%, which was not observed after SR_20%. Otherwise, the absence of mechanical control of biofilm showed that buffering capacity was comparable in the two groups before SR_20%, whereas after SR_20% the saliva’s buffering capacity of CF children was higher than ECC children. When biofilm was mechanically controlled, carbonic anhydrase VI activity did not change after SR_20% whereas the absence of mechanical control of biofilm reduced this enzyme activity after SR_20%. In conclusion, the mechanical control of biofilm did not change saliva’s ability to buffer the oral environment after SR_20% in children with ECC. On the other hand, CF children appeared to regulate more effectively the saliva’s pH than ECC children while the absence of mechanical control of biofilm mediated their pH-modifying ability after SR_20%.

Xerostomia and hyposalivation in patients with obstructive sleep apnoea

OBJECTIVE

(a) To report the xerostomia prevalence and severity in patients with obstructive sleep apnoea (OSA). (b) To assess the saliva pH in patients with OSA.

DESIGN

Simultaneous cohort observational clinical study.

SETTING

In Sleep Medicine Centre at Lomonosov Moscow State University from March to June 2019.

PARTICIPANTS

The study was conducted on 30 patients with OSA aged from 35 to 65 years.

MAIN OUTCOMES MEASURES

The diagnosis of sleep apnoea was made after standard polysomnography using the Domino programme. The severity of OSA was indicated using the Apnoea-Hypopnea Index. Xerostomia was evaluated using Fox's test. Hyposalivation was evaluated by measurement of salivary flow rate. Determination of the saliva pH was carried out with a pH metre. Statistical analysis was performed by one-way ANOVA and Tukey-Kramer multi-comparison test.

RESULTS

Twenty-two out of 30 (73.3%) patients were diagnosed with "dry mouth". Hyposalivation was observed in 6 out of 30 (20%). Dry mouth on awakening was observed in 60.0%, 72.7% and 88.9% of patients with mild, moderate and severe OSA, respectively. The average salivary flow rate was 0.28 mL/min, 0.24 mL/min and 0.14 mL/min, respectively. The average pH value in patients with mild, moderate and severe apnoea was 6.40 ± 0.017, 6.15 ± 0.27 and 5.87 ± 0.24, respectively.

CONCLUSIONS

In patient with mild and moderate OSA, the saliva amount and rate are similar (P > .05). With the increase of OSA severity, both these parameters change (P < .001). The acidity of the saliva was correlated with the level of OSA, and it statistically increased with the increment of the OSA severity (P < .05-P < .001).

Combined effect of starch and sucrose on carbonic anhydrase VI activity in saliva and biofilm of children with early childhood caries. Exposure to starch and sucrose alters carbonic anhydrase VI activity in saliva and biofilm

OBJECTIVES

This study aimed to investigate whether combined exposure to starch and sucrose modifies the activity of carbonic anhydrase VI (CA VI) in saliva (Study 1) and biofilm (Study 2) of children with early childhood caries (ECC).

MATERIAL AND METHODS

For Study 1 and Study 2, respectively, 54 and 46 preschoolers aged 4 to 5 were allocated into two groups: caries-free (CF) and with ECC. Children were exposed to rinses with sucrose, starch, and sucrose plus starch solutions. CA VI activity, pH, and buffering capacity (BC) were evaluated in saliva and biofilm.

RESULTS

In Study 1, a significant reduction in saliva pH was observed after sucrose and sucrose plus starch rinses. CA VI activity was influenced by ECC independently of the type of carbohydrate to which children were exposed. CA VI activity was higher in children with ECC; however, after rinses, CA VI activity was reduced. In Study 2, biofilm pH and BC were reduced after rinses with sucrose and sucrose plus starch. CA VI activity was significantly high before rinse in ECC group when compared with CF group; however, no difference was observed between groups after rinses.

CONCLUSIONS

In saliva, exposure to starch and sucrose (isolated or combined) induced a reduction in CA VI activity in children with ECC. In biofilm, the combination of starch and sucrose did not modify CA VI activity in ECC children.

CLINICAL RELEVANCE

The responsivity of the CA VI reflects directly in important parameters related to the pH maintenance on the oral cavity.

Analysis of salivary factors related to the oral health status in children

Early detection of oral disease is important to reduce its severity and increase the likelihood of successful treatment. This study aimed to perform a quantitative assessment of the saliva components as a first stage of the research to screen oral homeostasis. Here, saliva secretions collected from children were evaluated, and their constituents were analyzed to investigate the potential correlations between the buffering capacity and a range of salivary factors. Subjects aged 3-16 years in the primary, mixed, or permanent dentition stage, were selected for this study. The following salivary factors were analyzed: flow rate, total protein, total sugar quantifications, and constituent analyses using RT-PCR and western blotting. The associations between each factor and the buffering capacity were then analyzed using multiple regression analysis. Flow rate, BPIFA2 RNA level, histatin 1 and BPIFB1 protein levels as well as female sex were positively associated with buffering capacity. In contrast, total sugar concentration and MUC7 RNA levels showed a negative relationship with the buffering capacity. Some of these constituents may indicate oral homeostasis and are therefore potential biomarkers of oral health status. These results suggest that the analyses of the correlations between oral homeostasis and salivary factors are an effective strategy for identifying the susceptibility to oral diseases.

Activity of Carbonic Anhydrase VI is Higher in Dental Biofilm of Children with Caries

This study investigated pH, activity and concentration of carbonic anhydrase VI (CA VI) in dental biofilm of caries and caries-free children of 7–9 years old. Seventy-four children were selected and divided into two groups. The caries diagnosis was performed according to the WHO criteria, including the early caries lesion. After biofilm collection and pH determination, CA VI concentration and activity were determined by ELISA and Zimography respectively. The data were submitted to a Mann-Whitney test and to Pearson and Spearman correlation analyses. Means and standard deviations of dental caries for the caries group were of 3.162 ± 1.385. The biofilm pH was significantly higher in the caries-free group. The CA VI activity was significantly higher in biofilm of children with caries. The CA VI concentration was significantly higher in biofilm of caries-free children. In caries-free children, there was a moderate negative correlation between CA VI activity and concentration in dental biofilm as well as between pH and CA VI activity. A negative correlation between biofilm pH and CA VI concentration was found in the caries group. In conclusion, CA VI was shown to be more active in the biofilm of school children with caries in order to contribute to neutralization of biofilm acid.

Carbonic Anhydrase 6 Gene Variation influences Oral Microbiota Composition and Caries Risk in Swedish adolescents

Carbonic anhydrase VI (CA6) catalyses the reversible hydration of carbon dioxide in saliva with possible pH regulation, taste perception, and tooth formation effects. This study assessed effects of variation in the CA6 gene on oral microbiota and specifically the acidophilic and caries-associated Streptococcus mutans in 17-year old Swedish adolescents (n = 154). Associations with caries status and secreted CA6 protein were also evaluated. Single Nucleotide Polymorphisms (27 SNPs in 5 haploblocks) and saliva and tooth biofilm microbiota from Illumina MiSeq 16S rDNA (V3-V4) sequencing and culturing were analysed. Haploblock 4 (rs10864376, rs3737665, rs12138897) CCC associated with low prevalence of S. mutans (OR (95% CI): 0.5 (0.3, 0.8)), and caries (OR 0.6 (0.3, 0.9)), whereas haploblock 4 TTG associated with high prevalence of S. mutans (OR: 2.7 (1.2, 5.9)) and caries (OR: 2.3 (1.2, 4.4)). The TTG-haploblock 4 (represented by rs12138897(G)) was characterized by S. mutans, Scardovia wiggsiae, Treponema sp. HOT268, Tannerella sp. HOT286, Veillonella gp.1 compared with the CCC-haploblock 4 (represented by rs12138897(C)). Secreted CA6 in saliva was weakly linked to CA6 gene variation. In conclusion, the results indicate that CA6 gene polymorphisms influence S. mutans colonization, tooth biofilm microbiota composition and risk of dental caries in Swedish adolescents.