Changes in intestinal bacteria and imbalances of metabolites induced in the intestines of pancreatic cancer patients. human gut metagenome

The purpose of this study was to elucidate the characteristics of the intestinal environment in pancreatic cancer patients. Fecal samples were collected from healthy Japanese subjects (N=68) and patients with unresectable pancreatic cancer located in the body and tail (N=5, median age 73 years, range 70-89 years, two males, three females) using a collection container (Sarstedt K.K.). Exclusion criteria were as follows: Antibiotics taken for at least one week within six months, gastric or bowel medications such as proton pump inhibitors within two weeks, and taking prebiotics or probiotics within one month. There was no difference in the Shannon index and Principal Coordinate Analysis (PCoA) between healthy subjects and patients. However, there was a significant increase in oral-associated bacteria (Actinomyces (p=0.0000417, q=0.00312), Streptococcus (p=0.000358, q=0.0134), Veillonella (p=0.0227, q=0.243), Lactobacillus (p=0.0000417, q=0.00312)), with a significant decrease of Anaerostipes (p=0.0126, q=0.157) in the feces of pancreatic cancer patients. The metabolomic analysis indicated that intestinal metabolites such as organic and bile acids were lower in pancreatic cancer patients than in healthy subjects. Notably, propionic acid and deoxycholic acid were significantly lower. We showed that the intestinal environment of pancreatic cancer is characterized by an increase in oral-associated bacteria and by an imbalance of metabolites, but without changes in alpha and beta diversity.