妊娠期糖尿病患者治疗前后肠道菌群变化及其与血糖的相关性

目的探讨妊娠期糖尿病(gestational diabetes mellitus,GDM)患者治疗前后肠道菌群的变化特点,及其与75 g口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)血糖水平的关系。方法采用基于前瞻性队列研究的巢式病例对照研究方法。以2016年10月至2017年12月在北京大学第一医院妇产科建档及分娩的孕妇为研究对象。选取45例24~28孕周诊断为GDM的孕妇作为GDM组,并根据年龄和孕前体重指数(body mass index,BMI)按1∶1比例选取45例正常孕妇作为对照组。分别收集GDM治疗前(孕24~28周)及治疗后(孕36~40周)的粪便标本(对照组亦于相应孕周留取标本),利用Illumina Hiseq2500平台针对细菌16S rRNA的V3-V4可变区进行DNA测序,利用QIIME软件对样本进行生物信息学分析。采用t检验、Mann-Whitney U检验或χ2检验进行统计学分析。结果(1)治疗前GDM组肠道菌群Alpha多样性显著低于对照组(Chao1指数分别为443.9±72.9和474.0±63.3,t=2.104;Shannon指数分别为5.6±0.5和6.0±0.5,t=2.002;P值均<0.05),2组肠道菌群Beta多样性也存在明显差异(R2=0.04,P<0.05)。治疗后,GDM组和对照组肠道菌群的Alpha和Beta多样性的差异均无统计学意义。(2)GDM患者治疗前肠道布劳特氏菌和普拉梭菌的相对丰度高于对照组[M(P25~P75),分别为0.016(0.009~0.022)与0.011(0.007~0.016),U=782.000;0.114(0.076~0.141)与0.091(0.061~0.126),U=752.000;P值均<0.05]。阿克曼氏菌、Odoribacter和Butyricimonas的相对丰度低于对照组[分别为0.001(0.000~0.002)与0.001(0.000~0.005),U=745.000;0.001(0.000~0.004)与0.004(0.001~0.006),U=766.500;0.001(0.000~0.003)与0.003(0.001~0.005),U=710.000;P值均<0.05]。(3)OGTT服糖前水平和阿克曼氏菌、Odoribacter和Butyricimonas相对丰度呈负相关(r值分别为-0.325、-0.273和-0.284),服糖后1 h血糖水平和阿克曼氏菌、Butyricimonas相对丰度呈负相关(r值分别为-0.285和-0.265),服糖后2 h血糖水平和普拉梭菌相对丰度呈正相关(r=0.278),和阿克曼氏菌相对丰度呈负相关(r=-0.245);OGTT时间-血糖曲线的曲线下面积和阿克曼氏菌、Butyricimonas相对丰度呈负相关(r值分别为-0.321和-0.264)(P值均<0.05)。结论GDM患者肠道菌群组成和结构较对照组发生变化,GDM特征性菌群与OGTT血糖水平显著相关。通过治疗干预将GDM患者血糖恢复至正常水平,可改善GDM患者肠道菌群紊乱。

Different characteristics of gut microbiota before and after management of women with gestational diabetes mellitus and the association with blood glucose level

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(Chao1 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(0.076-0.141)vs 0.091(0.061-0.126),U=752.000;both P<0.05],but the relative abundances of Akkermansia,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 of Akkermansia(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.