Gastric microbiota and predicted gene functions are altered after subtotal gastrectomy in patients with gastric cancer

Abstract

Subtotal gastrectomy (i.e., partial removal of the stomach), a surgical treatment for early-stage distal gastric cancer, is usually accompanied by highly selective vagotomy and Billroth II reconstruction, leading to dramatic changes in the gastric environment. Based on accumulating evidence of a strong link between human gut microbiota and host health, a 2-year follow-up study was conducted to characterize the effects of subtotal gastrectomy. Gastric microbiota and predicted gene functions inferred from 16S rRNA gene sequencing were analyzed before and after surgery. The results demonstrated that gastric microbiota is significantly more diverse after surgery. Ralstonia and Helicobacter were the top two genera of discriminant abundance in the cancerous stomach before surgery, while Streptococcus and Prevotella were the two most abundant genera after tumor excision. Furthermore, N-nitrosation genes were prevalent before surgery, whereas bile salt hydrolase, NO and N2O reductase were prevalent afterward. To our knowledge, this is the first report to document changes in gastric microbiota before and after surgical treatment of stomach cancer.

Gastric microbes associated with gastric inflammation, atrophy and intestinal metaplasia 1 year afterHelicobacter pylorieradication

“…Ralstonia is a gram-positive bacterium with increasing incidence in respiratory infections 26–28. It was enriched in the gastric mucosa of patients with gastric cancer before subtotal gastrectomy 29. Taken together, the enrichment of these bacteria in subjects with inflammation in this study highlights their potential pathogenic role in promoting gastric inflammation.…”

Evaluation of gastric microbiome and metagenomic function in patients with intestinal metaplasia using 16S rRNA gene sequencing

“…We also enrolled one patient in the H. pylori‐ negative cancer group and two patients in the H. pylori‐ positive cancer group. To further analyze the differential characteristics of IM groups compared to cancer groups, we determined the microbiome sequences of 52 patients with gastric cancer from the NCBI (22 patients with H. pylori‐ negative cancer, and 30 patients with H. pylori‐ positive cancer; , , and ). In total, sequence data from 138 patients were analyzed in this study.…”

“…To improve the comparability and statistical power, microbiome sequences in gastric cancer tissues were downloaded from the NCBI (https://www.ncbi.nlm.nih.gov) following literature review . Inclusion criteria for microbiome sequences in the previous studies were as follows: (a) gastric microbiome derived from East Asian patients with gastric cancer and (b) known H. pylori- infection status.…”

Genomics and epidemiology for gastric adenocarcinomas

“…The findings of this study were limited by the low number of individuals (n = 5/group) and the methods used (a small set of hybridization of probes), but suggested the microbiota diversity to be consistently reduced in GACs. More recently, the effects of subtotal gastrectomy on the microbiota present in the stomach tissue of six GAC patients were evaluated [47]. They found that bacterial diversity increased after surgery and that Ralstonia and Helicobacter decreased in abundance after tumor excision.…”