The oral microbiome and salivary proteins influence caries in children aged 6 to 8 years

Abstract

Background Oral microbiome and salivary proteins play a critical role in the occurrence and development of caries. In this study, we used metagenomic and metaproteomic analyses to explore the microbiological and proteinic biomarkers and investigate the etiology of caries in 6–8 years old children. Our study aims to offer a better comprehension of these factors and the relationship with caries, and these findings might facilitate caries risk assessment and provide a basis for future prevention strategies. Methods Children 6 to 8 years old living in rural isolated areas including 40 caries-active subjects and 40 caries-free subjects were recruited. Supragingival plaque and unstimulated saliva were collected for 16S rDNA pyrosequencing and isobaric tags for relative and absolute quantitation (iTRAQ) technique coupled with quantitative nano-flow liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively. Results We found 6 phyla and 13 genera predominant in all the samples, and differences in relative abundances can be observed. The Alpha diversity analysis demonstrated that the richness and diversity of the bacterial communities were similar between children with caries-free and caries-active groups; LEfSe detected differences in the bacterial community including Dialister, Selenomonas, Actinomyces, and Mogibacterium in the caries-active group (P < 0.05) and Capnocytophaga, Fusobacterium, Desulfuromonadales, Haemophilus, and Porphyromonas in the caries-free group(P < 0.05). The core microbiome was defined as 18 predominant genera in children with caries. The results of the salivary proteome identified 9135 unique peptides and 1662 proteins group from 20 salivary samples. Two hundred fifty-eight proteins were differentially expressed between the caries-free and caries-active groups. Conclusions The diversity of the microbial community has little effect on caries but some bacteria with different relative abundance between the caries-active and caries-free group could be considered as potential biomarkers for children with caries. In addition, as a critical host factor of caries, the salivary proteins are different in caries-free and caries-active groups.

Downregulation of Salivary Proteins, Protective against Dental Caries, in Type 1 Diabetes

“…S100A7 is a calcium- and zinc-binding protein with a prominent role in regulating the immune response and antimicrobial humoral response, and has also been associated with dental caries [ 31 ]. Accordingly, it was found to be significantly downregulated (fold change = −1.7) in G1–C comparison.…”

“…The number of studies trying to correlate salivary proteins and dental caries has considerably increased [ 7 , 24 , 26 , 27 , 28 , 29 , 30 ]. It has been reported that changes in salivary protein compositions are involved in dental caries etiology [ 26 , 29 , 31 , 32 ]. These findings suggest the potential use of salivary proteins as biological indicators of dental caries.…”

Detection of Dental Caries Using Salivary Biomarkers – A Systematic Review

“…Another study performed salivary proteome and identified 9135 unique peptides & 1662 proteins group from 20 salivary samples. 258 proteins were differentially expressed between the cariesfree and caries-active groups [6]. Given the unique protein profile associated with caries prevalence and severity, more research into the mechanisms underlying salivary proteins for caries susceptibility or resistance, as well as their translation from the laboratory to clinical practice, is required.…”

“…Salivary protein is considered as one important factor for monitoring health and illness. Saliva proteins have been shown to influence dental health and homeostasis, maintain a stable ecology, and limit the growth of cariogenic bacteria [6]. Despite the fact that several studies have demonstrated that previous caries experience is the best predictor of future caries, salivary biomarkers are widely promoted, which provides simple chair side kits for the purpose.…”

Cariogenic and Pro Health Taxa in the Oral Cavity Among Children and Adults A Scoping Review

“…Plaque bacteria are shed in the saliva (17), but the amount may also vary by disease stage. It is also possible that saliva plays an ancillary role in cariogenesis or in preventing caries (18). There also may be multiple pathways to dental caries, and/or the processes leading to caries may depend on behavioral or physiologic factors associated with age, for example, diet, or dentition.…”