Gut microbiome and blood glucose control in type 1 diabetes: a systematic review

Front Endocrinol (Lausanne). 2023 Nov 15:14:1265696. doi: 10.3389/fendo.2023.1265696. eCollection 2023.

Abstract

Objective: The risk of developing micro- and macrovascular complications is higher for individuals with type 1 diabetes (T1D). Numerous studies have indicated variations in gut microbial composition between healthy individuals and those with T1D. These changes in the gut ecosystem may lead to inflammation, modifications in intestinal permeability, and alterations in metabolites. Such effects can collectively impact the metabolic regulation system, thereby influencing blood glucose control. This review aims to explore the relationship between the gut microbiome, inflammation, and blood glucose parameters in patients with T1D.

Methods: Google Scholar, PubMed, and Web of Science were systematically searched from 2003 to 2023 using the following keywords: "gut microbiota," "gut microbiome," "bacteria," "T1D," "type 1 diabetes," "autoimmune diabetes," "glycemic control," "glucose control," "HbA1c," "inflammation," "inflammatory," and "cytokine." The examination has shown 18,680 articles with relevant keywords. After the exclusion of irrelevant articles, seven observational papers showed a distinct gut microbial signature in T1D patients.

Results: This review shows that, in T1D patients, HbA1c level was negatively correlated with abundance of Prevotella, Faecalibacterium, and Ruminococcaceae and positively correlated with abundance of Dorea formicigenerans, Bacteroidetes, Lactobacillales, and Bacteriodes. Instead, Bifidobacteria was negatively correlated with fasting blood glucose. In addition, there was a positive correlation between Clostridiaceae and time in range. Furthermore, a positive correlation between inflammatory parameters and gut dysbiosis was revealed in T1D patients.

Conclusion: We draw the conclusion that the gut microbiome profiles of T1D patients and healthy controls differ. Patients with T1D may experience leaky gut, bacterial translocation, inflammation, and poor glucose management due to microbiome dysbiosis. Direct manipulation of the gut microbiome in humans and its effects on gut permeability and glycemic control, however, have not been thoroughly investigated. Future research should therefore thoroughly examine other potential pathophysiological mechanisms in larger studies.

Keywords: 16S rRNA; autoimmue diabetes; glycated hemoglobin; serum glucose level; shotgun sequencing; time in range.

Publication types

  • Systematic Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Glucose / metabolism
  • Diabetes Mellitus, Type 1*
  • Dysbiosis
  • Gastrointestinal Microbiome* / physiology
  • Glycated Hemoglobin
  • Glycemic Control
  • Humans
  • Inflammation

Substances

  • Blood Glucose
  • Glycated Hemoglobin

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by a grant from the University of Naples Federico II, Ricerca Dip 2021. Project funded under the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.3—Call for proposals No. 341 of 15 March 2022 of Italian Ministry of University and Research funded by the European Union—NextGenerationEU; Project code PE00000003, Concession Decree No. 1550 of 11 October 2022 adopted by the Italian Ministry of University and Research, CUP D93C22000890001, Project title ON Foods—Research and innovation network on food and nutrition Sustainability, Safety and Security—Working ON Foods. JA is PhD student of CRESCENDO Doctorate Programme that received funding by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie programme (MSCA-COFUND-2020) with Grant Agreement No. 101034245