부산대학교 도서관

Simple Summary: The high incidence and mortality of colorectal cancer (CRC) have influenced society to promote research in this field. Dysbiosis of the intestinal microbiota occurring in CRC has been extensively studied. However, microbial shifts occurring at the initial stages of mucosal alterations are less known. In this work, the fecal microbiota of volunteers diagnosed with intestinal polyps were compared with the microbial compositions of nonpathological control volunteers, thereby focusing on the nature of the hyperplastic polyps or conventional adenomas, as well as on the degree of dysplasia (low grade vs. high grade) in the last ones as indicators of colorectal cancer risk development. The findings provide insights into the microbiota changes occurring at the early stages of intestinal mucosal lesions. This work could set a starting point for further studies focusing on the influence of diet and lifestyle factors on the initial alterations of the intestinal mucosa and for the proposal of strategies for their prevention. Progressive intestinal mucosal damage occurs over years prior to colorectal cancer (CRC) development. The endoscopic screening of polyps and histopathological examination are used clinically to determine the risk and progression of mucosal lesions. We analyzed fecal microbiota compositions using 16S rRNA gene-based metataxonomic analyses and the levels of short-chain fatty acids (SCFAs) using gas chromatography in volunteers undergoing colonoscopy and histopathological analyses to determine the microbiota shifts occurring at the early stages of intestinal mucosa alterations. The results were compared between diagnosis groups (nonpathological controls and polyps), between samples from individuals with hyperplastic polyps or conventional adenomas, and between grades of dysplasia in conventional adenomas. Some microbial taxa from the Bacillota and Euryarchaeota phyla were the most affected when comparing the diagnosis and histopathological groups. Deeper microbiota alterations were found in the conventional adenomas than in the hyperplastic polyps. The Ruminococcus torques group was enriched in both the hyperplastic polyps and conventional adenomas, whereas the family Eggerthellaceae was enriched only in the hyperplastic polyps. The abundance of Prevotellaceae, Oscillospiraceae, Methanobacteriaceae, Streptococcaceae, Christensenellaceae, Erysipelotrichaceae, and Clostridiaceae shifted in conventional adenomas depending on the grade of dysplasia, without affecting the major SCFAs. Our results suggest a reorganization of microbial consortia involved in gut fermentative processes. [ABSTRACT FROM AUTHOR]