miR-203 Expression in Exfoliated Cells of Tongue Coating Represents a Sensitive and Specific Biomarker of Gastroesophageal Reflux Disease

Establishment of a Standard Tongue Coating Collection Method for Microbiome Studies

Objective: Recently, researchers have been focusing on characterizing the tongue coating microbiome from patients with digestive tract disease. However, to the best of our knowledge, the tongue coating collection methods have not been standardized until now. This article focuses on bridging this gap by exploring and validating the conditions suitable for the collection of tongue coating samples. Methods: One hundred forty-one healthy subjects were involved in the standardization of the tongue coating collection method. We conducted our standardization experiment by comparing different sampling tools, different preservation solutions, different scraping times, and different storage days with preservation at room temperature. The tongue coating samples from 59 normal individuals were analyzed using 16S ribosomal RNA (rRNA) gene-sequencing technology. The assessment of the quality of extracted DNA was used to verify our established method. We separated the 59 subjects into two groups (aged and younger), and the sequencing results were used to explore the age-related changes in microbiome. Results: Sterile oral swab B is suitable for the collection of tongue coating samples. To obtain a sufficient amount of DNA from a tongue coating sample, we recommend 30 times of tongue coating scraping. Normal saline, phosphate-buffered saline, and commercial preservation solution are all suitable for short-term sample storage (<1 hour). The commercial long-term preservation solution, which stores samples at room temperature (0 hour to 7 days) and can provide for fast commercial transportation, ensures the integrity of the sample DNA as well as the stability of the DNA quality. By using the established method, extracted DNA from all the 59 normal individuals' tongue coating samples passed an appropriate quality bar for microbiome studies. The average value of OD 260/280 is 1.72 ± 0.10; the average total DNA amount is 334.92 ng (±183.81 ng). The bacterial diversity of the tongue coating is increased and the bacterial community composition changes greatly in the NC group (aged normal subjects). Fusobacteriota is found as the dominant bacteria phyla in aged normal subjects with the 16S rRNA gene-sequencing technology. At the genus level, the relative abundance of Fusobacterium, Haemophilus, and Leptotrichia are significantly higher in aged individuals (all p < 0.05), and Neisseria, Streptococcus, and Porphyromonas are significantly higher in younger individuals (all p < 0.05). Conclusion: A participant-friendly tongue coating collection method for microbiome analyses can be established with good reliability and reproducibility. By taking advantage of our established method and 16S rRNA gene sequencing, significant differences were found in diversity and composition of tongue coating microbiota between aged and younger individuals, which contributes to a better understanding of the age-related composition of tongue coating microbiota.

Noninvasive, MultiOmic, and Multicompartmental Biomarkers of Reflux Disease: A Systematic Review

BACKGROUND AND AIMS

Gastroesophageal reflux disease (GERD) is a prevalent gastrointestinal disorder that may complicate conditions such as obstructive airway disease. Our group has identified predictive biomarkers of GERD in particulate exposed first responders with obstructive airway disease. In addition, GERD diagnosis and treatment is costly and invasive. In light of these clinical concerns, we aimed to systematically review studies identifying noninvasive, multiOmic, and multicompartmental biomarkers of GERD.

METHODS

A systematic review of PubMed and Embase was performed using keywords focusing on reflux disease and biomarkers and registered with PROSPERO. We included original human studies in English, articles focusing on noninvasive biomarkers of GERD published after December 31, 2009. GERD subtypes (non-erosive reflux disease and erosive esophagitis) and related conditions (Barrett's Esophagus [BE] and Esophageal Adenocarcinoma). Predictive measures were synthesized and risk of bias assessed (Newcastle-Ottawa Scale).

RESULTS

Initial search identified n = 238 studies andn 13 articles remained after applying inclusion/exclusion criteria. Salivary pepsin was the most studied biomarker with significant sensitivity and specificity for GERD. Serum assessment showed elevated levels of Tumor Necrosis Factor-alpha in both GERD and Barrett's. Exhaled breath volatile sulfur compounds and acetic acid were associated with GERD. Oral Microbiome: Models with Lautropia, Streptococcus, and Bacteroidetes showed the greatest discrimination between BE and controls vs Lautropia; ROCAUC 0.94 (95% confidence interval; 0.85-1.00).

CONCLUSION

Prior studies identified significant multiOmic, multicompartmental noninvasive biomarker risks for GERD and BE. However, studies have a high risk of bias and the reliability and accuracy of the biomarkers identified are greatly limited, which further highlights the need to discover and validate clinically relevant noninvasive biomarkers of GERD.

Correlation analysis and prognostic value of miR-29a-3p expression and CYP2C19 genotypes in exfoliated cells from tongue coating of patients with gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux disease (GERD) is a highly prevalent and troublesome disease. Several differentially expressed microRNAs (miRNAs) have been found in GERD.

OBJECTIVE

This study was to analyze the correlation of miR-29a-3p expression and CYP2C19 genotypes in exfoliated cells from tongue coating of GERD patients and its prognostic value.

METHODS

Tongue coating specimens were collected from 130 GERD patients and 70 healthy volunteers and their clinical baseline information was recorded. miR-29a-3p expression in exfoliated cells from tongue coating was determined via RT-qPCR, and its diagnostic efficiency on GERD was evaluated via receiver operating characteristic curve. CYP2C19 genotypes and their correlation with miR-29a-3p were analyzed via polymerase chain reaction restriction fragment length polymorphism technique. The adverse events of patients were documented via 12-month follow-up. The impact of miR-29a-3p expression on the healing rate of patients was analyzed via Kaplan-Meier method. Qualification of miR-29a-3p as an independent prognostic factor of GERD patients was analyzed via multivariate Cox regression analysis.

RESULTS

miR-29a-3p was highly-expressed in exfoliated cells from tongue coating of GERD patients. miR-29a-3p expression had high specificity and sensitivity in diagnosing GERD. CYP2C19 genotypes in GERD patients comprised rapid metabolizers, intermedia metabolizers, and poor metabolizers. miR-29a-3p expression showed a correlation with CYP2C19 genotypes. Higher miR-29a-3p expression predicted higher cumulative incidences of adverse outcomes. Highly-expressed miR-29a-3p was an independent prognostic factor for adverse outcomes of GERD patients.

CONCLUSION

High expression of miR-29a-3p aided the diagnosis and predicted poor prognosis of GERD patients.

Exosome-mediated effects and applications in inflammatory diseases of the digestive system

Exosomes are membranous vesicles containing RNA and proteins that are specifically secreted in vivo. Exosomes have many functions, such as material transport and signal transduction between cells. Many studies have proven that exosomes can not only be used as biomarkers for disease diagnosis but also as carriers to transmit information between cells. Exosomes participate in a variety of physiological and pathological processes, including the immune response, antigen presentation, cell migration, cell differentiation, and tumour development. Differences in exosome functions depend on cell type. In recent years, exosome origin, cargo composition, and precise regulatory mechanisms have been the focus of research. Although exosomes have been extensively reported in digestive tumours, few articles have reviewed their roles in inflammatory diseases of the digestive system, especially inflammatory-related diseases (such as reflux oesophagitis, gastritis, inflammatory bowel disease, hepatitis, and pancreatitis). This paper briefly summarizes the roles of exosomes in inflammatory diseases of the digestive system to provide a basis for research on the mechanism of inflammatory diseases of the digestive system targeted by exosomes.

Whiplash-Associated Dysphagia: Considerations of Potential Incidence and Mechanisms

Non-specific self-reports of dysphagia have been described in people with whiplash-associated disorders (WAD) following motor vehicle collision (MVC); however, incidence and mechanistic drivers remain poorly understood. Alterations in oropharyngeal dimensions on magnetic resonance imaging (MRI), along with heightened levels of stress, pain, and changes in stress-dependent microRNA expression (e.g., miR-320a) have been also associated with WAD, suggesting multi-factorial issues may underpin any potential swallowing changes. In this exploratory paper, we examine key biopsychosocial parameters in three patients with persistent WAD reporting swallowing change and three nominating full recovery after whiplash with no reported swallowing change. Parameters included (1) oropharyngeal volume with 3D MRI, (2) peritraumatic miR-320a expression, and (3) psychological distress. These factors were explored to highlight the complexity of patient presentation and propose future considerations in relation to a potential deglutition disorder following WAD. The three participants reporting changes in swallowing all had smaller oropharyngeal volumes at < 1 week and at 3 months post injury and lower levels of peritraumatic miR-320a. At 3 months post MVC, oropharyngeal volumes between groups indicated a large effect size (Hedge's g = 0.96). Higher levels of distress were reported at both time points for those with persistent symptomatology, including self-reported dysphagia, however, this was not featured in those nominating recovery. This paper considers current evidence for dysphagia as a potentially under-recognized feature of WAD and highlights the need for future, larger-scaled, multidimensional investigation into the incidence and mechanisms of whiplash-associated dysphagia.

Expression of Serum Exosomal and Esophageal MicroRNA in Rat Reflux Esophagitis

Gastroesophageal reflux disease (GERD) is a common upper gastrointestinal disease. However, the role of exosomal microRNAs (miRNAs) and esophageal miRNAs in GERD has not been studied. A rat model of acid reflux esophagitis was used to establish a novel diagnosis marker for GERD and examine dynamics of miRNA expression in GERD. Rats were sacrificed 3 (acute phase), 7 (sub-acute phase) and 21 days (chronic phase) after induction of esophagitis. Exosomes were extracted from serum, and the expression patterns of serum miRNAs were analyzed. Four upregulated miRNAs (miR-29a-3p, 128-3p, 223-3p and 3473) were identified by microarray analysis. The expression levels of exosomal miR-29a-3p were significantly higher in the chronic phase of reflux esophagitis compared with controls, and increased expression of miR-29a-3p was specific to chronic reflux esophagitis. Esophageal miR-223-3p expression was higher compared with controls, and gradually decreased from acute to chronic phase in esophagitis. In conclusion, exosomal miR-29a-3p and esophageal miR-223-3p might play roles in GERD.