Effect Of Linagliptin On Intestinal Flora In Newly Diagnosed Type 2 Diabetes Patients

Objective:To explore the differences in glycemic and lipid metabolism related indexes and intestinal flora in patients with type 2 diabetes before and after treatment with linagliptin,and to test whether linagliptin affects the composition and structure of intestinal flora in patients with T2 DM,and to explore the correlation between intestinal flora and glycolipid metabolism indexes.Methods:Eleven patients with newly diagnosed type 2 diabetes mellitus(T2DM)who met the criteria were included as the experimental group,and 10 healthy people with matching age and body mass index(BMI)were selected as the control group during the same period.The experimental group was given oral linagliptin tablets 5mg/ day continuous treatment for 3 months,after treatment.Serum and fecal samples were collected from the control group and the pre-treatment and post-treatment groups,and the changes of intestinal flora and clinical indexes were observed and compared between the control group and the pre-treatment and post-treatment groups.Information on intestinal flora was obtained by high-throughput sequencing of the16S-r RNA gene in fecal samples.Clinical indicators include: fasting blood glucose(FBG),2 hours postprandial blood glucose(2h PBG),glycosylated hemoglobin(Hb A1c),triglycerides(TG),cholesterol(TC),high density lipoprotein cholesterol(HDL-C),low density lipoprotein cholesterol(LDL-C),C-reactive protein(CRP),fasting insulin function(FINS),insulin function 2 hours after meal(2h INS),fasting C-peptide(FCP),2 hours after meal C-peptide(2h CP),HOMA-IR,HOMA-β.Results:1.Clinical indicators: There were no significant differences in age,sex,body weight,BMI,waist circumference,hip circumference,and waist-to-hip ratio between the control group and the group treated before treatment(P > 0.05).The biochemical indices of TC,LDL-C,FBG,2h PBG,Hb A1 c,FINS,2h INS and HOMA-IR in the pre-treatment group were higher than those in the control group(P < 0.05)and were not significantly different between the two groups,while the biochemical indices of the FCP,2h CP,HOMA-β groups were less than those of the control group(P < 0.05).There were no significant differences in TG,HDL-C or CRP levels between the 2groups(P > 0.05).Body weight,BMI,waist circumference,hip circumference,and waist-to-hip ratio were not significantly different between the two groups in the study before and after linagliptin treatment(P > 0.05).Comparison of biochemical indexes between groups: The levels of FCP,2h CP,HOMA-β in the post-treatment group were higher than those in the pre-treatment group(P < 0.05),and the levels of TG,LDL-C,FBG,2h PBG,Hb A1 c,FINS,2h INS and HOMA-IR were lower than those in the pretreatment group(P < 0.05).In the present study.TC,HDL-C and CRP levels did not differ significantly between the two groups(P > 0.05).2.High-throughput sequencing was performed for the fecal sample to obtain the amplicon sequence variant(ASV).A total of 1636 different ASV characteristic sequences were obtained for the three groups of samples.The intestinal flora diversity analysis and intestinal flora analysis at the level of phyla and genus were obtained based on the construction of ASV.Alpha diversity analysis showed that the Chao1,ACE and Shannon indexes in the pre-treatment group were lower than those in the control group(P < 0.05),and the Chao1,ACE and Shannon indexes of patients after treatment were higher than those before treatment(P < 0.05),suggesting that species abundance and diversity of intestinal flora increased after treatment with linagliptin.Principal coordinate analysis of Beta diversity showed significant differences in microflora structure among the three groups.3.There were significant changes in the composition of phylum and genus of intestinal flora among the three groups.Compared with the control group,the proportions of Firmicutes,Proteobacteria,Prevotella and opportunistic pathogen includes Escherichia-Shigella,Streptococcus,Klebsiella,Eubacterium in the pretreatment group significantly increased,while the proportions of Bacteroidetes,Verrucomicrobiota and probiotic includes Bacteroides,Bifidobacterium,Faecalibacterium,Ruminococcus Roseburia decreased(P < 0.05).After treatment with linagliptin,the proportions of Firmicutes,Proteobacteria,Prevotella,Escherichia-Shigella,Klebsiella and Eubacterium decreased significantly.While the proportion of Bacteroidetes,Actinobacteria,Verrucomicrobiota,Bacteroides,Bifidobacterium,Akkermansia,Faecalibacterium,Ruminococcus,Roseburia,Ligilactobacillus and Clostridium increased(P < 0.05).4.High abundance bacteria in the pre-and post-treatment groups were correlated with glycemic and lipid metabolism indexes,Bacteroides,Bifidobacterium,Akkermansia,Ruminococcus and Clostridium were negatively correlated with TG,LDL-C,FBG,2h PBG,Hb A1 c,HOMA-IR and were positively correlated with HDLC.Escherichia-Shigella,Prevotella and Klebsiella were positively correlated with TG,LDL-C,FBG,2h PBG,Hb A1 c and HOMA-IR.Conclusions:1.Linagliptin can improve glucose and lipid metabolism and islet function in patients with type 2 diabetes mellitus;2.The species richness and species diversity of intestinal flora in patients with type 2 diabetes were lower than those in the control group and the group after treatment with linagliptin.3.Intestinal flora of patients with type 2 diabetes showed an imbalance in the proportion of bacteria and bacteria genera,and the abundance of opportunistic pathogens increased and the abundance of beneficial bacteria decreased.4.Linagliptin improves intestinal flora disorder in patients with type 2 diabetes by increasing the abundance of beneficial bacteria and decreasing the abundance of opportunistic bacteria.5.Increased abundance of probiotic as well as decreased abundance of opportunistic pathogen can improve glucose lipid metabolism in patients with type 2 diabetes.