Gene expression and metabolic activity of Streptococcus mutans during exposure to dietary carbohydrates glucose, sucrose, lactose, and xylitol.

Recent RNA sequencing studies have given us a deeper insight into the cariogenic impact of carbohydrate sources in the bacterium Streptococcus mutans, the principal microbial agent in dental caries etiopathogenesis. The process of dental caries development is facilitated by the ability of this bacterium to ferment some carbohydrates into organic acids contributing to a pH decrease in the oral cavity and the demineralization of the hard tissues of the tooth. Furthermore, in dental caries progression, biofilm formation, which starts and ends with free planktonic cells, plays an important role and has several unique properties called virulence factors. The most cariogenic carbohydrate is sucrose, an easily metabolizable source of energy that induces the acidification and synthesis of glucans, forming typical bacterial cell clumps. We used multifaceted methodological approaches to compare the transcriptomic and metabolomic profiles of S. mutans growing in planktonic culture on preferred and nonpreferred carbohydrates and in fasting conditions. Streptococcus mutans in a planktonic culture with lactose produced the same pH drop as glucose and sucrose. By contrast, xylitol and lactose showed high effectiveness in regulating intracellular polysaccharide metabolism, cell wall structure, and overall virulence involved in the initial phase of biofilm formation and structure but with an opposite pattern compared with sucrose and glucose. Our results confirmed the recent findings that xylitol and lactose play a vital role in biofilm structure. However, they do not reduce its formation, which is related to the creation of a cariogenic environment.

The Role of the Oral Microbiota in the Etiopathogenesis of Oral Squamous Cell Carcinoma.

Dysbiosis in the oral environment may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). This review aims to summarize the current knowledge about the association of oral microbiota with OSCC and to describe possible etiopathogenetic mechanisms involved in processes of OSCC development and progression. Association studies included in this review were designed as case-control/case studies, analyzing the bacteriome, mycobiome, and virome from saliva, oral rinses, oral mucosal swabs, or oral mucosal tissue samples (deep and superficial) and comparing the results in healthy individuals to those with OSCC and/or with premalignant lesions. Changes in relative abundances of specific bacteria (e.g., Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sp.) and fungi (especially Candida sp.) were associated with OSCC. Viruses can also play a role; while the results of studies investigating the role of human papillomavirus in OSCC development are controversial, Epstein-Barr virus was positively correlated with OSCC. The oral microbiota has been linked to tumorigenesis through a variety of mechanisms, including the stimulation of cell proliferation, tumor invasiveness, angiogenesis, inhibition of cell apoptosis, induction of chronic inflammation, or production of oncometabolites. We also advocate for the necessity of performing a complex analysis of the microbiome in further studies and of standardizing the sampling procedures by establishing guidelines to support future meta-analyses.

Biomarkers for non-endoscopic examination of esophageal mucosa.

Gastroesophageal reflux disease (GERD) is a multifactorial disease; an individual´s genetic predisposition may contribute to the development of this disorder. Endoscopic methods and histological examination are commonly used to diagnose GERD and its complications such as Barretts esophagus (BE) and esophageal adenocarcinoma (EAC). For BE screening in high-risk individuals as well as monitoring the development of BE dysplasia, esophageal mucosa samples could be taken using modern non-endoscopic procedures to minimize invasiveness of the procedure and improve patient adherence and compliance with a treatment. Esophageal mucosa samples taken by non-endoscopic or endoscopic biopsy can be analyzed both by immunohistochemistry and molecular biology analysis for specific biomarkers. Markers such as caudal type homeobox 2 (CDX2) and protein p53 have found their use in GERD diagnosis, and therefore research in recent years has focused on identifying other biomarkers that could reliably predict the development and progression of BE or EAC. This review article summarizes information on modern non-endoscopic methods of sampling from the esophagus mucosa and biomarkers, which have been studied in connection with the prediction and diagnosis of BE and EAC and have a potential for the use in clinical practice.

Confocal laser endomicroscopy in the diagnostics of esophageal diseases: a pilot study.

BACKGROUND: Probebased confocal laser endomicroscopy (pCLE) is a novel diagnostic technique for endoscopy which enables a microscopic view at a cellular resolution in realtime. Endoscopic detection of early neoplasia in the distal esophagus is difficult and often these lesions can be missed. The aim of the pilot study was to obtain characteristic pCLE figures in esophageal diseases for following studies, and to evaluate the possible future role of pCLE in the diagnostics of dysplastic Barretts esophagus (BE) or early esophageal adenocarcinoma (EAC). METHODS: A review of the current literature was performed and previously published pCLE images and classifications of esophageal diseases were searched and studied first. In phase two of the pilot study patients with esophageal diseases such as reflux esophagitis, BE and EAC were enrolled and scheduled for upper endoscopy with pCLE. A healthy cohort was also included. RESULTS: From January 2019 to July 2019, a total of 14 patients were enrolled in this prospective pilot study: 3 patients with reflux esophagitis, 4 with BE, 3 with EAC and 4 persons were included in the healthy cohort. The endoscopy with pCLE was performed and characteristic pCLE figures were obtained. The correct diagnoses based on realtime pCLE were evaluated by an endoscopist in 11 of the 14 cases (78.6 %). CONCLUSION: It was possible to obtain typical pCLE images of esophageal diseases during a standard capassisted endoscopic procedure. pCLE seems to be a feasible new technique in BE surveillance and early neoplastic lesion detection. However, more studies and data on larger number of patients are needed.

Oral diseases in diabetic patients.

In this paper, the authors summarize current findings on the relationship between diabetes mellitus (DM) and oral tissue diseases. They study the effect of diabetes on the condition of hard dental tissues, oral mucosa and salivary glands and explain how these undesirable changes occur. They focus primarily on the bilateral relationship between diabetes and periodontitis, common pathogenetic traits of both diseases and on the effect of periodontal treatment on basic metabolic diseases. They show that diabetes not only negatively affects the condition of periodontal tissues, but inflammatory disease of periodontium is also a risk factor for hyperglycemia. The authors point to the emerging closer co-operation between diabetologists and parodontologists (Perio-Diabetes Workshop in 2017) and consider possibilities of effective prevention and better motivation of diabetics for oral health care.

The effect of IL-4 gene polymorphisms on cytokine production in patients with chronic periodontitis and in healthy controls.

Chronic periodontitis (CP) is an inflammatory disease of the teeth-supporting tissues in which genetic predisposition, dental plaque bacteria, and immune mechanisms all play important roles. The aim of this study was to evaluate the occurrence of IL-4 gene polymorphisms in chronic periodontitis and to investigate the association between polymorphisms and cytokines production after bacterial stimulation. Sixty-two subjects (47 CP patients and 15 healthy controls) with detected two polymorphisms in the IL-4 gene (-590C/T and intron 3 VNTR) were examined. Production of cytokines (IL-1α, IL-1ß, IL-4, IL-5, IL-6, IL-10, IL-17, TNFα, INFγ, and VEGF) was studied after in vitro stimulation of isolated peripheral blood by mitogens (Pokeweed mitogen, Concanavalin A), dental plaque bacteria (Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, and Prevotella intermedia), and Heat Shock Protein (HSP) 70 by the Luminex multiplex cytokine analysis system. The results were correlated with IL-4 genotypes in patients with CP and healthy controls. The mononuclear cells isolated from peripheral blood of CP patients with selected IL-4 polymorphisms significantly altered the production of IFNγ, IL-10, IL-1ß, IL-1α, TNFα, and IL-6 after stimulation by HSP 70 or selected bacteria (from P < 0.001 to P < 0.05). IL-4 gene polymorphisms may influence the function of mononuclear cells to produce not only interleukin-4 but also other cytokines, especially in patients with CP.