Department of Medical Sciences, Faculty of Medicine & Health Sciences, Universiti Sains Islam Malaysia (USIM), Negeri Sembilan, Malaysia.
Public Health Unit, Department of Primary Health Care, Faculty of Medicine & Health Sciences, Universiti Sains Islam Malaysia (USIM), Negeri Sembilan, Malaysia.
Front Cell Infect Microbiol. 2022 Aug 15;12:943427. doi: 10.3389/fcimb.2022.943427. eCollection 2022.
Evidence of gut microbiota involvement in regulating glucose metabolism and type 2 diabetes mellitus (T2DM) progression is accumulating. The understanding of microbial dysbiosis and specific alterations of gut microbiota composition that occur during the early stages of glucose intolerance, unperturbed by anti-diabetic medications, is especially essential. Hence, this systematic review was conducted to summarise the existing evidence related to microbiota composition and diversity in individuals with prediabetes (preDM) and individuals newly diagnosed with T2DM (newDM) in comparison to individuals with normal glucose tolerance (nonDM). A systematic search of the PubMed, MEDLINE and CINAHL databases were conducted from inception to February 2021 supplemented with manual searches of the list of references. The primary keywords of "type 2 diabetes", "prediabetes", "newly-diagnosed" and "gut microbiota" were used. Observational studies that conducted analysis of the gut microbiota of respondents with preDM and newDM were included. The quality of the studies was assessed using the modified Newcastle-Ottawa scale by independent reviewers. A total of 18 studies (5,489 participants) were included. Low gut microbial diversity was generally observed in preDM and newDM when compared to nonDM. Differences in gut microbiota composition between the disease groups and nonDM were inconsistent across the included studies. Four out of the 18 studies found increased abundance of phylum along with decreased abundance of in newDM. At the genus/species levels, decreased abundance of , , , and and increased abundance of , a, and were observed in the disease groups in at least two studies. was also found to positively correlate with fasting plasma glucose (FPG), HbA1c and/or homeostatic assessment of insulin resistance (HOMA-IR) in four studies. This renders a need for further investigations on the species/strain-specific role of endogenously present in glucose regulation mechanism and T2DM disease progression. Differences in dietary intake caused significant variation in specific bacterial abundances. More studies are needed to establish more consistent associations, between clinical biomarkers or dietary intake and specific gut bacterial composition in prediabetes and early T2DM.
越来越多的证据表明肠道微生物群在调节葡萄糖代谢和 2 型糖尿病（T2DM）进展中发挥作用。了解在葡萄糖耐量受损早期发生的微生物失调和肠道微生物组成的特定变化尤为重要，此时不受抗糖尿病药物的影响。因此，进行了这项系统综述，以总结有关在葡萄糖耐量正常的个体（非 DM）相比，处于糖尿病前期（preDM）和新诊断为 T2DM（newDM）个体的肠道微生物组成和多样性的现有证据。从一开始到 2021 年 2 月，对 PubMed、MEDLINE 和 CINAHL 数据库进行了系统检索，并补充了对参考文献列表的手动搜索。主要关键词为“2 型糖尿病”、“糖尿病前期”、“新诊断”和“肠道微生物群”。纳入了分析 preDM 和 newDM 患者肠道微生物群的观察性研究。独立评审员使用改良的纽卡斯尔-渥太华量表评估研究质量。共纳入 18 项研究（5489 名参与者）。与非 DM 相比，preDM 和 newDM 通常观察到肠道微生物多样性较低。疾病组与非 DM 之间的肠道微生物组成差异在纳入的研究中不一致。在 18 项研究中有 4 项发现 newDM 中门水平的丰度增加，同时丰度减少。在属/种水平，在至少两项研究中观察到疾病组中属的丰度降低，如 、 、 、 和 ，和种的丰度增加，如 、a、 和 。在四项研究中还发现 与空腹血浆葡萄糖（FPG）、HbA1c 和/或胰岛素抵抗稳态评估（HOMA-IR）呈正相关。这表明需要进一步研究内源性存在的在葡萄糖调节机制和 T2DM 疾病进展中的物种/菌株特异性作用。饮食摄入的差异导致特定细菌丰度的显著变化。需要更多的研究来建立更一致的关联，即在糖尿病前期和早期 T2DM 中，临床生物标志物或饮食摄入与特定肠道细菌组成之间的关联。
