Project description:Background & Aims: Because the pathophysiology of GERD is not fully understood, presently used drug target only one or more of the known underlying mechanisms but are not fully effective in all patients. 1Identifying novel central targets may pave the way to develop more effective agents. Methods: A surgical model of sub-chronic reflux esophagitis was developed. Wistar rats were pretreated for 7days with omeprazole (standard proton pump inhibitor) or STW5 (herbal preparation of established efficacy in gastro-intestinal disorders). Treatment was continued for 10days after surgery, rats were sacrificed and esophagi excised. Histological, proteomic and transcriptomic methods were applied to identify reflux induced changes and treatment responses. Results: Protection against reflux induced inflammation was achieved by both test drugs. Both reduced macroscopic and microscopic lesions of the esophagi as well as most measured pro-inflammatory cytokines without significantly affecting NF-kB activity. Proteomic and transcriptomic analysis identified CINC1-3, MIP-1/3Î±, MIG, RANTES and IL-1Î² as highly relevant mediators in GERD. Other highly regulated genes were those of IL-6, CCL3, CCL7 and LOX-1. Many affected cyto-/chemokines were involved in the TREM-1 signaling pathway. The fatty acid receptor GPR84 was highly up-regulated in esophagitis but down-regulated by both drugs. This was confirmed by Western blot and immune-histochemical staining, showing for the first time expression of this receptor in esophageal tissue and its possible involvement in GERD. Conclusion: STW5 and omeprazole target a broad spectrum of molecules involved in immunological and inflammatory processes, of which IL-8 (CINC1-3), TREM-1 pathway and GPR84 are proposed to be most promising novel targets for the treatment of GERD. Refluxesophagitis was surgically induced. Wistar rats were pretreated for 7 days with omeprazole or STW5. Treatment was continued for 10days after surgery, rats were sacrificed and esophagi exiced. The study had 5 groups. Group 1: sham operated, Group 2: esophagitis group, untreated, Group3: esophagitis treated with STW5 0.5ml/kg. Group 4: esophagitis treated with STW5 2ml/kg. Group 5: esophagitis treated with Omeprazole (30mg/kg). 4 microarrays from esophageal tissue and blood from 4 animals of each group were performed.

Project description:The distal esophagus is an important anatomical area where gastric acid reflux can cause reflux esophagitis (RE), Barrett's esophagus (BE) (intestinal metaplasia), and esophageal adenocarcinoma (EA). The incidence of EA has increased 6-fold in the U.S. since the 1970s, parallel to a significant increase in the prevalence of gastroesophageal reflux diseases (GERD). Although specific host factors might predispose one to disease risk, such a rapid increase in incidence must be predominantly environmental. The cause remains unknown. Our hypothesis is that changes in the foregut microbiome are associated with EA and its precursors, RE and BE in the GERD sequence. We will conduct a case control study to characterize the microbiome in every stage of the GERD sequence as well as analyze the trend in changes in the microbiome along disease progression toward EA. Specific Aim 1. To conduct a comprehensive population survey of the foregut microbiome and demonstrate its association with GERD sequence, by a 16S rRNA gene survey. We will analyze samples of the foregut microbiome at three anatomic loci: mouth, distal esophagus, and gastric corpus. Changes of the microbiota in the distal esophagus will be correlated with the phenotypes. Spatial relationship between the esophageal microbiota and upstream (mouth) and downstream (stomach) foregut microbiotas as well as temporal stability of the microbiome-disease association will also be examined. Specific Aim 2. To define distal esophageal metagenome and demonstrate its association with GERD sequence, by shotgun metagenomic analysis. We will first classify samples of the metagenome into metagenotypes by between-sample k-mer distance and correlate the metagenotypes with the four phenotypes. Subsequent detailed analyses will include pathway-disease and gene-disease associations. DNA viruses and fungi, if identified, also will be correlated with the phenotypes. A significant association between the foregut microbiome composition and GERD sequence, if demonstrated, will be the first step for eventually testing the causal hypothesis that an abnormal microbiome is required for the development of the sequence of phenotypic changes toward EA. If EA and its precursors represent a microbial ecological disease, treating the cause of GERD might become possible, for example, by normalizing the microbiome through use of antibiotics, probiotics, or prebiotics. Causative therapy for GERD could prevent its progression and reverse the current trend of increasing incidence of EA.

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Beyond acid suppression: Novel therapeutic targets for gastro-esophageal reflux disease based on a murine model (esophageal tissue)

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