Saliva transit in patients with gastroesophageal reflux disease

Identification of key pathways and genes in Barrett's esophagus using integrated bioinformatics methods

Barrett's esophagus (BE) is a premalignant lesion of esophageal adenocarcinoma. The aim of the present study was to investigate the possible mechanisms and biomarkers of BE. To identify the differentially expressed microRNAs (DEmiRNAs) and genes (DEGs) in BE, the miRNA expression profile GSE20099 and the gene expression profiles GSE26886, GSE13083 and GSE34619 were obtained from the Gene Expression Omnibus (GEO) database. DEGs and DEmiRNAs were screened for using the GEO2R tool. Using DAVID, functional and pathway enrichment analysis was performed to explore the biological function of identified DEGs. The protein-protein interaction (PPI) network was detected using STRING and constructed by Cytoscape software. Furthermore, targets of identified DEmiRNAs were predicted by the miRecords database, then integrated with the identified DEGs to obtain key genes involved in BE. In total, 311 DEGs were identified. These genes were significantly enriched in the pancreatic secretion, metabolic pathways and cytochrome P450 drug metabolism pathways. In the PPI network, 16 hub genes, including keratin 16, cystic fibrosis transmembrane conductance regulator, involucrin, protein kinase C α and cadherin 17 were identified. Following integration of the predicted target genes of DEmiRNAs with DEGs, three key BE genes were identified: PRKCA, CDH17 and epiregulin. In conclusion, a comprehensive bioinformatics analysis of identified DEGs and DEmiRNAs was performed to elucidate potential pathways and biomarkers involved in the development of BE.

Timing of cortical activation during spontaneous swallowing

Saliva accumulation in the oropharynx generates an automatic pattern of swallowing in the brainstem in animals. Previous fMRI studies have found that spontaneous saliva and water swallows in humans evoked activation following swallow onset in both precentral motor and postcentral somatosensory cortical regions. Using event-related averaging of continuous functional near infrared spectroscopy (fNIRS), we examined cortical hemodynamic responses (HDR) from 5 s before to 35 s after spontaneous reflexive saliva swallow onset in the lateral postcentral somatosensory and precentral motor regions in both hemispheres in healthy volunteers. Three HDR changes from baseline were detected. First, the onset of HDR occurred 2 s before swallow onset in the left postcentral somatosensory area and 0.67 s before swallow onset in the right postcentral somatosensory area. Second, an early HDR peak amplitude occurred 3-4 s after swallow onset in all four regions. Z scores relative to baseline pre-swallow cortical activity levels averaged 20 and 22.7 s in the right and left somatosensory regions and 10 and 15.8 s in left and right motor areas, respectively. Finally, a late HDR peak occurring between 22 and 23 s after swallow onset in the somatosensory regions and 17-19 s in the motor areas likely resulted from esophageal peristalsis. Overall, cortical activation timing relative to swallow onsets showed activation began before the pharyngeal phase of swallowing in the somatosensory areas. This indicates that somatosensory triggering of swallowing occurs not only in the brainstem but also in the cortex for reflexive saliva swallowing in awake humans.

Adam, Eve and the reflux enigma: age and sex differences across the gastro-oesophageal reflux spectrum

INTRODUCTION

We present demographic differences across the gastro-oesophageal reflux disease (GORD) spectrum in a UK District General Hospital.

PATIENTS AND METHODS

Data were prospectively collected over 37 years. At endoscopy patients were categorized as: erosive oesophagitis (EO), Barrett's oesophagus (BO) or nonerosive reflux disease (NER). Analysis 1: comparison of EO, BO and NER 1977-2001 when the database for GORD without BO closed. Analysis 2: demographic differences in oesophageal adenocarcinoma (OAC) in total BO population diagnosed 1977-2011.

RESULTS

GORD 1977-2001 (n=11 944): sex, male predominance in EO and BO but not NER; male : female ratios, 1.81, 1.65, 0.87, respectively (P<0.0001); mean age at presentation, EO 54 years, BO 62 years, NER 50 years; women were older than men by 10, 7 and 6 years, respectively.BO 1977-2011: prevalent OAC, 87/1468 (6%); male : female ratio, 4.1 (P<0.0001); incident OAC, 54/1381 (3.9%); male : female ratio, 3.5 (P<0.0001). Among all BO, more men developed OAC (3 vs. 0.9%). Within each sex, proportion of OAC higher among men (4.9 vs. 2.3%); at OAC diagnosis women were slightly but not significantly older (69.9 vs. 72.3 years, P=0.322).

CONCLUSION

Two views may explain our findings. First, women have either milder reflux, or reduced mucosal sensitivity hence reflux remains silent for longer. Alternatively, women genuinely develop reflux later, that is, are more protected and for longer from developing GORD and its complications. Early evidence is emerging that female sex hormones may indeed have a protective role in GORD during the reproductive period. We suggest reflux and its consequences may be an example of 'protection' conferred on Eve.