Gene Expression Profiling of Inflammatory Cytokines in Esophageal Biopsies of Different Phenotypes of Gastroesophageal Reflux Disease: a cross-sectional study.

Abstract

Background: Patients clinical endoscopic phenotypes in gastroesophageal reflux disease (GERD) are classified as: Barrett's esophagus (BE), erosive esophagitis (EE) and non-erosive gastroesophageal reflux disease (NERD). NERD are subclassified in Abnormal acid exposure (AAE) and Normal acid exposure (NAE) according to pH monitoring study. The aim of this study was to characterize genes involved in the pathophysiology and immune response of GERD.Methods: This is an observational and cross-sectional study. All patients with BE, EE, AAE, NAE and control group were subjected to a superior endoscopy (with biopsies of esophageal mucosa). The cytokine mRNA relative quantification of target genes was conducted by RT-PCR. Changes in gene expression were assessed of the genes associated with inflammation in each disease phenotype. Statistical analysis of differential gene expression was performed by using Dunn's Multiple Comparison non-parametric test. A p value < 0.05 was considered as significant. Results: A total of 82 patients were included and they were divided into the following groups: Group BE 16 (19.51%), Group EE 23 (28.04%), Group AAE 13 (15.86%), NAE (15.86%) and Control Group 17 (20.73%). When comparing with control group we found: patients with BE showed an increased expression of IL-8 (P<0.005) and higher levels of: IL-10 and MMP-3, MMP-9 as well; patients with EE had higher levels of IL-1B, IL-6 and IL-10 (P<0.005), patients with AAE showed an increased expression of Il-1B, Il-6, IFN-γ and TNF-α (P<0.005). AAE had a higher expression of Il-1B and TNF-α than NAE (P<0.005). Conclusions: This study demonstrates the differential expression of mediators of inflammation in the esophageal mucosa of patients in GERD endoscopic phenotypes. MMP3 could be implicated in damage to esophageal mucosa. IL-1B and TNF-α could be a differential diagnosis between AAE and NAE in the non-erosive phenotype from endoscopic biopsies.

Methylation of the CpG at -299 bp from transcription start site of interleukin-1β is a sustained marker of inflammation exerted by TNFa on bone marrow-derived mesenchymal cells of healthy humans

“…It also exempli es the usage of previously developed procedures to determine CpG methylation [26]. As IL1B expression is used as a marker in clinics [21,[39][40][41], there is a particular signi cance of an approach studing DNA associated marks in addition to RNA expression. Since DNA is more stable, used approach to studying DNA methylation simpli es procedures and allows to analyse stored samples with potential RNA degradation [42][43][44].…”