| Purpose:In this study,we compared the differences in blood glucose,intestinal flora structure and short-chain fatty acid levels in patients with gastric cancer complicated with type 2 diabetes mellitus who underwent Roux-en-Y or Billorth II anastomosis.And we intended to investigate the effects of Roux-en-Y anastomosis on intestinal flora and its metabolite,short-chain fatty acids,and the relationship between intestinal flora and postoperative glycemic changes.Methods:1.Inclusion of study subjects: from January 2020 to January 2023,44 patients pathologically confirmed gastric cancer and clinically diagnosed type 2 diabetes mellitus with were recruited to undergo Billorth Ⅱ or Roux-en-Y anastomosis at The Second Affiliated Hospital of Nanchang University.2.Collection of patients’ datas and samples: gender,age,weight,height,BMI,TNM stage,FPG and 2h PG were collected from the two study groups.3.16 S r RNA sequencing of intestinal flora DNA: a combination of genomic DNA kit and bead beating method was used to extract DNA.PCR products were sequenced using Illumina Hi Seq 2000 platform,and sequencing results were analyzed by bioinformatics and multivariate statistics.4.Targeted metabolomics of fecal samples: we used gas chromatography-mass spectrometry(GC-MS)for the targeted determination of short-chain fatty acids.Results:1.There were no significant differences in gender,age,weight,height,BMI,TNM stage,FPG and 2h PG between the two groups.Comparison of time points before and after surgery within the same group: FPG and 2h PG at 1 month postoperatively were lower than those before surgery in both groups(P<0.05).Comparison between groups: FPG and 2h PG at 1 week postoperatively were not significantly different between the two groups.FPG and 2h PG at 1 month postoperatively were lower in patients in group B than in group A(P<0.05).2.Comparison of intestinal flora between two groups(1)The diversity analysis of intestinal flora in the two groups: the Chao 1 and Shannon were higher in group B than in group A.The results of PCOA and betweengroup difference analysis showed significant differences in intestinal flora between the two groups.The VENN plots suggested that there were 1994 and 1774 OTUs in groups A and B,respectively,accounting for 67.70%(1350/1994)and 63.70%(1130/1774).The results of LEf Se analysis showed that the relative abundance of Clostridia,Clostridiales,Bacteroideates,Bacteroidea,Bacteroideales,Bacteroides,Bifidobacteria,Bifidobact-eriaceae,and Bifidobacterium were significantly higher in group B than in group A.(2)The composition of the intestinal flora at the phylum level was analyzed in both groups: Firmicutes,Proteobacteria,Bacteroidetes,Actinobacteriawere the dominant phylum in the intestinal flora of both groups of patients.Further analysis showed that the relative abundance of Firmicutes(51.12±25.29% vs.40.25±17.45%)and Proteobacteria(33.41±26.64% vs.29.05±18.05%)was reduced in group B compared to group A,while the relative abundance of Actinobacteria(6.66±5.80% vs.8.70±11.60%)and Bacteroidetes(4.62±7.27% vs.18.00±10.63%;P<0.01)increased in relative abundance,with statistically significant differences.(3)The composition of the intestinal flora at the genus level was analyzed in both groups: Streptococcus,Lactobacillus,Prevotella,Akkermansia,and Clostridium were the top five dominant genera in Group A.Bacteroides,Faecalibacterium,Bifidobacterium,Sutterella,and Ruminococcaceae＿Ruminococcus were the top five dominant genera in Group B.Further analysis showed that the relative abundance of Bacteroides(0.85±1.13% vs.11.17±9.94%;P<0.01),Bifidobacterium(1.12±2.05%vs.6.88±11.79%)and Faecalibacterium(1.97±4.24% vs.8.47±9.26%;P<0.05)increased in group B compared to group A,while the relative abundance of Lactobacillus(4.70±9.71% vs.1.19±4.05%),Prevotella(3.17±7.05% vs.1.76±3.53%)and Streptococcus(13.25±17.47% vs.1.02±1.42%;P<0.05)decreased with statistically significant differences.3.Comparison of short-chain fatty acids between two groupsCompared with group A,the content of acetic acid(1.24±0.86 vs.2.05±0.65;P<0.05),propionic acid(0.45±0.45 vs.0.97±0.68;P<0.05)and butyric acid(0.23±0.27 vs.0.47±0.37;P<0.05)was significantly increased in group B,with statistically significant differences,while isobutyric acid(0.08±0.09 vs.0.11±0.09),valeric acid(0.10±0.15 vs.0.13±0.12)and caproic acid(0.01±0.01 vs.0.02±0.02)were slightly increased,and their differences were not statistically significant.4.Correlation of intestinal flora composition and short-chain fatty acid levels with blood glucose between two groupsAt the genus level,Bacteroides and Faecalibacterium were negatively correlated with FPG and 2h PG,while Bifidobacterium were negatively correlated with 2h PG and positively correlated with FPG.Lactobacillus,Prevotella and Streptococcus were negatively correlated with FPG and 2h PG.In addition,acetic acid,propionic acid,butyric acid,isobutyric acid,valeric acid and capric acid were negatively correlated with FPG and 2h PG.Conclusions:1.Roux-en-Y anastomosis reduces postoperative blood glucose in patients with gastric cancer complicated with type 2 diabetes mellitus and is superior to Billroth II anastomosis2.Postoperative blood glucose is closely related to intestinal flora in patients with gastric cancer combined with type 2 diabetes mellitus.Roux-en-Y anastomosis may act by regulating intestinal flora as well as short-chain fatty acid metabolism. |
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