Identification of the factor derived from gut microbiota associated with the progress of chronic hepatitis C

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K09015
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Gastroenterology
• Research Institution: Nagoya City University
• Principal Investigator: Inoue Takako 名古屋市立大学, 大学院医学研究科, 助教 (00431700)
• Co-Investigator(Renkei-kenkyūsha): TANAKA Yasuhito 名古屋市立大学, 医学(系)研究科(研究院), 教授 (90336694) ; NAKAYAMA Jiro 九州大学(連合), 農学研究科(研究院), 准教授 (40217930)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: chronic hepatitis Ｃ / gut microbiota / dysbiosis

Outline of Final Research Achievements

We performed a comparative study of gut microbiota composition between chronic hepatitis C (CHC) patients and healthy individuals. Compared with healthy individuals, bacterial diversity was lower in persons with HCV infection, with a decrease in the order Clostridiales and an increase in Streptococcus and Lactobacillus. Microbiota dysbiosis already appeared in the persistently normal serum alanine aminotransferase (PNALT) stage with the transient increase of Bacteroides and Enterobacteriaceae. Predicted metagenomics showed an increase in the urease gene mainly encoded by viridans streptococci during the progression of clinical stages, consistent with a significantly higher fecal pH in chronic hepatitis (CH) and liver cirrhosis (LC) than in healthy individuals or in the PNALT stage.
HCV infection is associated with gut dysbiosis, even in patients with mild liver disease. Additionally, overgrowth of viridans streptococci can account for hyperammonemia in CH and LC.

Free Research Field

gastroenterology