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Objective To investigate the gut microbial profiles of gestational mellitus diabetes (GDM) patients before and after treatment,and the relationship between gut microbiota and blood glucose level measured in 75 g oral glucose tolerance test (OGTT).Methods A prospective cohort-based nested case-control study was conducted in Peking University First Hospital from October 2016 to December 2017.Forty-five pregnancies at 24-28 gestational weeks with GDM (GDM group) and 45 healthy gravidas (control group)matched for age and pre-pregnancy body mass index (BMI) were involved.Stool samples of all participants were collected before (24-28 gestational weeks) and after (36-40 gestational weeks) treatment.The V3-V4 region of the 16S rRNA gene was sequenced on the Illumina Hiseq 2500 platform,and the results were analyzed.QIIME software was used for bioinformatics analysis.Student's t-test,Mann-Whitney U test,and Chi-square test were used for statistical analysis.Results (1) Before treatment,the Alpha diversity of the GDM group was significantly reduced compared with that of the control group (Chaol index:443.9±72.9 vs 474.0± 63.3,t=2.104,P＜0.05;Shannon index:5.6±0.5 vs 6.0±0.5,t=2.002,P＜0.05),and a significant difference in Beta diversity was also observed between the two groups (R2=0.04,P＜0.05).However,a significant difference was shown in neither Alpha nor Beta diversity between the two groups after the treatment.(2) Before treatment,the relative abundances of Blautia and Faecalibacterium of the GDM group were significantly higher than those of the control group [M (P25-P75):0.016 (0.009-0.022) vs 0.011 (0.007-0.016),U=782.000;0.114 (0.076-0.14 1) vs 0.091 (0.061-0.126),U=752.000;both P＜0.05],but the relative abundances ofAkkermansia,Odoribacter and Butyricimonas were significantly lower [0.001 (0.000-0.002) vs 0.001 (0.000-0.005),U=745.000;0.001 (0.000-0.004) vs 0.004 (0.001-0.006),U=766.500;0.001 (0.000-0.003) vs 0.003 (0.001-0.005),U=710.000;all P＜0.05].(3) A negative relationship was found between the fasting glucose level of OGTT and the relative abundances of Akkermansia,Odoribacter and Butyricimonas (r=-0.325,-0.273 and-0.284;all P＜0.05),and between the one-hour-OGTT glucose level and the relative abundances of Akkermansia and Butyricimonas (r=-0.285 and -0.265,both P＜0.05).The two-hour-OGTT glucose level was positively related to the relative abundance of Faecalibacterium (r=0.278,P＜0.05),but negatively related to the relative abundance ofAkkermansia (r=-0.245,P＜0.05).The area under the OGTT time-glucose curve was negatively related to the relative abundances of Akkermansia and Butyricimonas (r=-0.321 and-0.264,both P＜0.05).Conclusions There are significant differences in gut microbial composition and structure between GDM and healthy pregnant women,which are significantly associated with OGTT blood glucose level.Euglycemia achieved after GDM management could improve gut microbiota disorder.
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In recent years,research on human microbiota has become more and more in-depth.It has been found that microorganisms in human body affect the functions of the host's digestive,nervous,immune and many other systems,imperceptibly changing the growth and development of human beings and disease progression.This review summarized the results of research on intestinal microbiota in early life,suggesting that the period from early pregnancy to two years old is a critical period for the colonization of human gut microbiota.It is vital to understand and investigate the factors influencing bacterial colonization at this time.
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Objective To investigate the distribution characteristics of the gut microbiome in infants with different delivery mode and feeding pattern at six weeks of life.Methods A total of 60 infants delivered between June and September in 2017 at Peking University First Hospital were recruited.According to delivery modes and feeding patterns,they were respectively divided into two groups,which were vaginal delivery (n=42)and cesarean delivery (n=18) groups,and exclusively breastfeeding (n=40) and mixed-feeding (n=20) groups.Stool samples of all subjects were collected at six weeks after birth.The V3-V4 region of 16s rRNA gene was sequenced on Illumina Hiseq 2500 platform,and the results were analyzed with SILVA database and QIIME software.Independent samples t-test or Mann-Whitney U test was used for statistical analysis.Results (1)Eight bacterial phyla and 146 genera were identified in the 60 stool samples.Firmicutes,Proteobacteria,Actinobacteria and Bacteroidetes were four dominant phyla,and Bifidobacterium,Clostridium,Klebsiella,Bacteroides,Streptococcus,Escherichia-Shigella,Veillonella and Faecalibacterium were the top eight most abundant genera.(2) At the phyla level,the vaginal delivery group was characterized with reduced Firmicutes (0.56 ± 0.1 0 vs 0.42± 0.20,t=2.94,P＜0.05) and increased Actinobacteria and Bacteroidetes [0.04 (0.01-0.11)vs 0.20 (0.05-0.36),U=223,P＜0.05;0.05 (0.01-0.23) vs 0.09 (0.02-0.29),U=315,P＜0.05] as compared with the cesarean delivery group.However,there was no significant difference in the four dominant phyla between exclusively breastfeeding and mixed-feeding groups (all P＞0.05).At the genus level,the relative abundance of Bifidobacterium was higher in the vaginal delivery group than in the cesarean delivery group [0.19 (0.02-0.36) vs 0.01 (0.00-0.07),U=210,P＜0.01].Similarly,there was no significant difference in the eight dominant genus between exclusively breastfeeding and mixed-feeding groups(all P＞0.05).(3) The vaginal delivery group showed significantly lower Shannon and Simpson indexes than the cesarean delivery group [4.26 (3.61-5.52) vs 5.48± 1.19,U=227,P＜0.05;0.86±0.08 vs 0.94 (0.92-0.97),U=194,P＜0.05],while no significance was found in operational taxonomic unit (OTU) number and Chaol index (all P＞0.05).However,there was no significant difference in OTU number,Chaol,Shannon or Simpson index between the exclusively breastfeeding and the mixed-feeding groups (all P＞0.05).Conclusion The early infancy is a critical period for the establishment of gut microbiome.Significant differences in the composition and diversity of gut microbiota are found between infants born vaginally and abdominally,but not in infants with different feeding patterns.