Gut Microbes and Microbial Metabolites in Colorectal Cancer Complicat Ed With Different Serum Albumin Levels

Background: Patients with colorectal cancer (CRC) are at risk of malnutrition. Gut microbes and microbial metabolites are involved in the initiation and development of CRC. Aims: : To investigate serum protein levels in CRC patients and explore the role of gut microbes and microbial metabolites in CRCs complicated with different serum albumin levels. Methods: : Overall, 398 CRC patients and same number of healthy volunteers in Huzhou Central Hospital from January 2016 to December 2018 were recruited to compare serum protein levels. A total of 30 and 56 stool samples from CRC patients were used to detect intestinal microbes and microbial metabolites, respectively. Bacterial 16S V3-V4 and fungal ITS ribosomal DNA genes were sequenced and gas chromatography/mass spectrometry (GC/MS) was performed to detect microbial metabolites. Results: : Some serum protein-related indicators in the CRC group were lower than those in the control group (p＜0.05). The total protein and albumin levels in colon cancer patients were lower than those in rectal cancer patients (p＜0.05). The higher abundance of Sutterella is correlated with lower serum albumin level in CRCs. There were statistically significant differences in the abundance of fungi including Agaricomycetes， Simplicillium, Sclerotiniaceae, and Exophiala among patients with different serum albumin levels. Multiple gut bacteria and fungi are closely related to serum albumin levels.We found some characteristic microbial metabolites in CRCs complicated with different serum protein levels. Conclusions: : The different serum albumin levels were associated with the gut microbes and microbial metabolites in CRCs. Trial registration: Correlation analysis of intestinal flora and its metabolites with tumor nutritional status in patients with colorectal cancer,ChiCTR1900022460,Registered 12 April 2019,http://www.chictr.org.cn/edit.aspx?pid=37950&htm=4