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 >59% of bariatric surgeries performed being VSG. Surprisingly, there has never been a complete molecular characterization of the fundus and corpus of the gastric greater curvature. Here we compare and contrast the molecular make-up of these regions.

Methods

Recruitment was performed under IRB# 2014-0047, UMMC. Gastric tissue from the fundus and corpus were resected (N=24) during surgery. RNA was extracted and submitted for RNAseq analysis and qPCR validation studies performed.

Results

Participants were primarily Caucasian (79.15%) and female (95.8%). Mean BMI, body weight, and age were 46.1 kg/m2, 121.6 kg, and 43.29 years, respectively. RNAseq provided 26,228 gene transcripts of which, 4,518 had minimal reads. Overall, 432 gene transcripts were significantly different between the fundus and corpus (P<0.05). High fidelity was found between the RNAseq data set and qPCR validation. Significant examples included: progastricsin, acid chitinase, and ghrelin in the fundus, and carbonic anhydrase 12 in the corpus. Of the very highly expressed genes in both regions, 87% were present in both the fundus and corpus of the stomach, indicating substantial overlap.

Conclusions

A myriad of genes expressed in the region of stomach resected in VSG display a multiplicity of functions yet to be described. Unearthing these genes and their physiologic roles is crucial for understanding how limiting their expression post-VSG leads to early improvement or resolution of obesity-related comorbidities. While the impact of VSG on long-term health outcomes and remission of chronic disease is not completely known, therapies aiming to inhibit these genetic targets may provide non-invasive and reversible alternatives to effectively treat obesity.