Effect of glycerol on reconstructed human oral mucosa

Glycerol metabolism supports oral commensal interactions

During oral biofilm development, interspecies interactions drive species distribution and biofilm architecture. To understand what molecular mechanisms determine these interactions, we used information gained from recent biogeographical investigations demonstrating an association of corynebacteria with streptococci. We previously reported that Streptococcus sanguinis and Corynebacterium durum have a close relationship through the production of membrane vesicle and fatty acids leading to S. sanguinis chain elongation and overall increased fitness supporting their commensal state. Here we present the molecular mechanisms of this interspecies interaction. Coculture experiments for transcriptomic analysis identified several differentially expressed genes in S. sanguinis. Due to its connection to fatty acid synthesis, we focused on the glycerol-operon. We further explored the differentially expressed type IV pili genes due to their connection to motility and biofilm adhesion. Gene inactivation of the glycerol kinase glpK had a profound impact on the ability of S. sanguinis to metabolize C. durum secreted glycerol and impaired chain elongation important for their interaction. Investigations on the effect of type IV pili revealed a reduction of S. sanguinis twitching motility in the presence of C. durum, which was caused by a decrease in type IV pili abundance on the surface of S. sanguinis as determined by SEM. In conclusion, we identified that the ability to metabolize C. durum produced glycerol is crucial for the interaction of C. durum and S. sanguinis. Reduced twitching motility could lead to a closer interaction of both species, supporting niche development in the oral cavity and potentially shaping symbiotic health-associated biofilm communities.

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.

Symptom management to alleviate thirst and dry mouth in critically ill patients: A randomised controlled trial

BACKGROUND

Critically ill patients often experience coexisting symptoms. Thirst, in particular, appears to be an important symptom, having the highest prevalence, intensity, and induction of distress, and is significantly correlated with other symptoms. However, thirst and dry mouth are not usually assessed or treated.

OBJECTIVES

The aim of the study was to demonstrate the effectiveness of an intervention bundle to relieve thirst and dry mouth.

METHODS

The present study was a randomised controlled trial in which critically ill patients were allocated to an experimental or control group. The intervention bundles, including vitamin C sprays, peppermint water mouthwash, and a lip moisturiser, were provided to the experimental group for 3 days, whereas patients in the control group were exposed to the placebo interventions, including saline sprays, 40 °C water mouthwash, and wetting the lips with water.

RESULTS

A total of 61 patients were recruited to the study; 65.6% (n = 41) were men, and the average age was 64.2 ± 16.8 years. The average decrease in thirst intensity and oral mucosa situation scores after the interventions was larger in the experimental group patients relative to controls (1.27 and 0.36 vs. 0.19 and 0.1 points, respectively; p < 0.05). Being male, scoring highly on the Acute Physiology and Chronic Health Evaluation II scale, not receiving diuretics, and having higher serum sodium levels were potential predictors of thirst and oral dryness.

CONCLUSIONS

The interventional bundle used in this study was shown to be a promising approach that can relieve thirst intensity and dry mouth, which are pervasively distressful to critically ill patients.

CLINICAL TRIAL REGISTRATION NUMBERS

The study was registered on the www.Chictr.org.cn under the identification number ChiCTR1900022873.