Background. Vertical sleeve gastrectomy (VSG) is a surgical weight loss procedure that resects 80% of the stomach, creating a tube linking the esophagus to the duodenum. Because of the efficacy and relative simplicity of VSG, it is preferred in the U.S with VSG currently at >61% of bariatric surgeries performed. Surprisingly, there has never been a complete molecular characterization of the human stomach fundus and corpus. Here we compare and contrast the molecular make-up of these regions. Methods. We performed a prospective study to obtain gastric tissue samples from patients undergoing VSG. Paired fundus and corpus samples were obtained Whole genome transcriptome analysis was performed by RNA sequencing, with key findings validated by qPCR. Results. Participants were primarily female (95.8%) and white (79.15%). Mean BMI, body weight, and age were 46.1 kg/m2, 121.6 kg, and 43.29 years, respectively. Overall, 432 gene transcripts were significantly different between the fundus and corpus (p<0.05). A significant correlation was found between the RNAseq data set and qPCR validation, demonstrating robust gene expression differences. Significant genes included: progastricsin, acid chitinase, gastokine 1 and 2 in both fundus and corpus. Of the very highly expressed genes in both regions, 87% were present in both the stomach's fundus and corpus, indicating substantial overlap. Conclusions. Despite significant overlap in the greater curvature gene signature, regional differences exist. Given that the mechanism of VSG is partly unresolved, the potential that the resected tissue may express genes that influence long-term body weight regulation is unknown and could influence VSG outcomes.
FXR is a molecular target for the effects of vertical sleeve gastrectomy