1. Ecophysiological consequences of alcoholism on human gut microbiota: implications for ethanol-related pathogenesis of colon cancer.
- Author
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Tsuruya A, Kuwahara A, Saito Y, Yamaguchi H, Tsubo T, Suga S, Inai M, Aoki Y, Takahashi S, Tsutsumi E, Suwa Y, Morita H, Kinoshita K, Totsuka Y, Suda W, Oshima K, Hattori M, Mizukami T, Yokoyama A, Shimoyama T, and Nakayama T
- Subjects
- Acetaldehyde chemistry, Acetaldehyde metabolism, Adolescent, Adult, Aged, Alcohol Dehydrogenase genetics, Alcoholism pathology, Aldehyde Dehydrogenase, Mitochondrial genetics, Bacteroides genetics, Cluster Analysis, Colorectal Neoplasms metabolism, Colorectal Neoplasms microbiology, Feces chemistry, Feces microbiology, Female, Humans, Male, Middle Aged, Phenotype, Polymorphism, Genetic, Principal Component Analysis, RNA, Ribosomal, 16S chemistry, RNA, Ribosomal, 16S genetics, Ruminococcus genetics, Sequence Analysis, DNA, Streptococcus genetics, Young Adult, Alcoholism microbiology, Bacteroides isolation & purification, Colorectal Neoplasms pathology, Ethanol metabolism, Gastrointestinal Microbiome, Ruminococcus isolation & purification, Streptococcus isolation & purification
- Abstract
Chronic consumption of excess ethanol increases the risk of colorectal cancer. The pathogenesis of ethanol-related colorectal cancer (ER-CRC) is thought to be partly mediated by gut microbes. Specifically, bacteria in the colon and rectum convert ethanol to acetaldehyde (AcH), which is carcinogenic. However, the effects of chronic ethanol consumption on the human gut microbiome are poorly understood, and the role of gut microbes in the proposed AcH-mediated pathogenesis of ER-CRC remains to be elaborated. Here we analyse and compare the gut microbiota structures of non-alcoholics and alcoholics. The gut microbiotas of alcoholics were diminished in dominant obligate anaerobes (e.g., Bacteroides and Ruminococcus) and enriched in Streptococcus and other minor species. This alteration might be exacerbated by habitual smoking. These observations could at least partly be explained by the susceptibility of obligate anaerobes to reactive oxygen species, which are increased by chronic exposure of the gut mucosa to ethanol. The AcH productivity from ethanol was much lower in the faeces of alcoholic patients than in faeces of non-alcoholic subjects. The faecal phenotype of the alcoholics could be rationalised based on their gut microbiota structures and the ability of gut bacteria to accumulate AcH from ethanol.
- Published
- 2016
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