Effects of gabexate mesylate on the gut microbiota and metabolomics in rats with sepsis
Authors: Cui Yuqing , Zhang Xiaojuan , Wang Yuze , Zhang Zihao , Ding Xianfei , Liang Huoyan , Wang Dong , Sun Yali , Liu Shaohua , Duan Xiaoguang , Lu Yibin , Sun Tongwen 
Published: May 2022

Abstract
Background: Sepsis develops in millions of people worldwide annually. Only 30%–40% of septic shock cases have positive microbial culture results[1]. Currently, there is no clear early diagnostic marker for sepsis. The gut microbiota and metabolomics significantly change in sepsis. Previous studies have reported that gabexate mesylate (GM) could alleviate liver and lung injury and high inflammatory status in sepsis. This study aimed to examine the changes in gut microbiota and metabolomics after GM application.Methods: Sixty Sprague–Dawley (SD) rats were randomly divided into the sham control group (SC), sepsis after cecal ligation and puncture (CLP) group, and intraperitoneal GM injection 1 h after CLP (GM) group. Colonic feces were collected to examine the gut microbiota and metabolism using 16SrRNA and liquid chromatography-mass spectrometry, and bioinformatics methods were performed to analyze the microbiome and metabolomics. The mortality rate of the three groups was measured 24 h after the procedure. Moreover, lung tissues were collected for hematoxylin-eosin (HE) staining.Result: 1. In the comparison of the SC and GM groups, the relative abundance of Firmicutes and ratio of Firmicutes to Proteobacteria in the CLP group decreased at the phylum level, and the Proteobacteria increased. The Lactobacillus at the genus level of the CLP group significantly decreased, while the Escherichia–Shigella and Akkermansia increased. The α-diversity and β-diversity of the CLP and SC groups were significantly different. The principal coordinate analysis showed that the microbiota in the SC and GM groups were similar and had a large difference from that of the CLP group. Linear discriminant analysis effect size analysis showed that the different genera of the CLP and SC groups were Lactobacillus, Romboutsia, and Escherichia–Shigella. The different genera of the CLP and GM groups were Lactobacillus, Pygmaiobacter, Erysipelotrichaceae_UCG_003, Escherichia–Shigella, and Akkermansia. 2. Principal component analysis indicated that the metabolic profiles of SC and GM groups were close to each other and significantly separated from the CLP group. Orthogonal partial least squares discriminant analysis showed that CLP and SC groups and CLP and GM groups could be separated into different groups because of metabolic differences. It was found that GM mainly regulates sphingolipid metabolism, histidine metabolism, steroid biosynthesis, glycerophospholipid metabolism, primary bile acid biosynthesis, and other metabolic pathways. 3. Combined analysis of differential gut microbiota and metabolites showed that CLP-rich genera (Akkermansia, Escherichia–Shigella, and Proteus) were positively associated with LysoPE (15:0/0:0) and quinolinic acid, and GM-rich genus (Lactobacillus) was negatively correlated with LysoPE (15:0/0:0) and quinolinic acid. CLP-rich genera (Akkermansia, Escherichia–Shigella, and Proteus) were negatively correlated with leukotriene B4 and 9,10-DHOME, and GM-rich genus (Lactobacillus) was positively correlated with leukotriene B4 and 9,10-DHOME. 4. The mortality rate in the CLP group was significantly higher than those in the SC and GM groups. HE staining showed that inflammatory infiltration, edema, and structural damage of the lung tissues in the CLP group were more severe than those in the SC and GM groups.Conclusion: GM could affect the changes in Lactobacillus, Akkermansia, Escherichia–Shigella, and other genera; regulate the relative abundance of LysoPE (15:0/0:0), quinolinic acid, leukotriene B4, 9,10-DHOME, and other differential metabolites; and attenuate acute lung injury caused by sepsis, which may provide a potential mechanism for GM application in sepsis treatment.