Su2119 Introduction of Enteric Methanogens Reduces Intestinal Transit and Alters Oral Glucose Tolerance

Abstract

min functional MRI scan, followed by 10 min acid infusion, and followed by a 6 min functional MRI scan. This protocol was repeated after bilateral vagotomy. For functional imaging we acquired gradient ECHO images on a 9.4T Bruker MRI scanner with the following EPI parameters-matrix 96 x 96,FOV 35mm,TR=2s,TE=18.76 ms, 1 mm slice. All analysis was performed using FSL/FLIRT for image registration and AFNI(NIH) for connectivity analysis. We used seed-based connectivity analysis with placement of seeds within the cingulate cortex (anterior, middle, and retrosplenial). Group comparisons were made using ANOVA and Monte-Carlo simulations for multiple comparison correction. Correlation maps were generated and plotted with a corrected p-value. Results: We found that across all correlation coefficient thresholds, esophageal acid infusion was associated with significantly fewer correlated cortical voxels to the cingulate cortex (Figure 1). We found that when placing seeds within the anterior cingulate cortex, there was statistically significant diminished connectivity with the primary and secondary somatosensory, and primary and secondary motor areas after acid infusion. These alternations were not observed following bilateral cervical vagotomy (Figure 2). The findings of diminished connectivity were also demonstrated when placing seeds in the middle cingulate cortex and retrosplenial cortex. (p-value threshold of 0.02, cluster size of 6 voxels) Conclusions: Esophageal acid stimulation alters functional connectivity of the acid responsive regions of the brain. Esophageal acid induced brain functional connectivity changes are vagally mediated. These findings may play a role in further understanding of acid-related esophageal disorders.