<p>Effects of Metformin on the Gut Microbiota in Obesity and Type 2 Diabetes Mellitus</p>

Abstract

Metformin is a first-line treatment for type 2 diabetes mellitus (T2DM); however, its underlying mechanism is not fully understood. Gut microbiota affect the development and progression of T2DM. In recent years, an increasing number of studies has focused on the relationship between metformin and gut microbiota, suggesting that metformin might exert part of its hypoglycemic effect through these microbes. However, most of these results were not consistent due to the complex composition of the microbiota, the differences between species, the large variation between individuals, and the differences in experimental design, bringing great obstacle for our better understanding of the effects of metformin on the gut microbiota. Here, we reviewed the published papers concerning about the impacts of metformin on the gut microbiota of mice, rats, and humans with obesity or T2DM, and summarized the changes of gut microbiota composition caused by metformin and the possible underlying hypoglycemic mechanism which is related to gut microbiota. It was found that the proportions of some microbiota, such as phyla Bacteroidetes and Verrucomicrobia and genera Akkermansia, Bacteroides and Escherichia , were significantly affected by metformin in several studies. Metformin may exert part of hypoglycemic effects by altering the gut microbiota in ways that maintain the integrity of the intestinal barrier, promote the production of short-chain fatty acids (SCFAs), regulate bile acid metabolism, and improve glucose homeostasis.

The Relationship between the Gut Microbiome and Metformin as a Key for Treating Type 2 Diabetes Mellitus

“…Furthermore, gut dysbiosis has also been observed in T2DM patients [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Based on the hypothesis that metformin targets the human gastrointestinal tract, the gut microbiome has attracted attention as a key factor in the treatment of T2DM [ 36 , 37 , 38 , 39 , 40 , 41 ]. Thus, this review focused on the various studies related to the gut microbiome and its association with the anti-diabetic effects of metformin.…”

Perilla Seed Oil Alleviates Gut Dysbiosis, Intestinal Inflammation and Metabolic Disturbance in Obese-Insulin-Resistant Rats

“…Metformin exerts a hypoglycemic effect by effectively controlling the blood glucose of obese and diabetic patients [44]. Furthermore, metformin modulates the gut microbiota, leading to maintaining gut barrier integrity, enhancing the shortchain fatty acid production, and improving glucose homeostasis [45,46]. Metformin has evidenced that improving the expression of tight junction occludin-1 in the gut increased the abundance of beneficial bacteria, such as Lactobacillus and Akkermansia muciniphila, attenuated endotoxemia and oxidative stress, and promoted the anti-oxidative Nrf2 system, resulting in an improved glucose metabolism and insulin signaling pathway in the liver and the muscles of HFD-fed mice [47].…”

Effects of anti-aging interventions on intestinal microbiota

“…Interestingly, metformin can maintain intestinal barrier function, improve glucose homeostasis and exert hypoglycemic effects by affecting intestinal flora. 97 Recent studies have shown that the incidence of colorectal cancer (CRC) in patients with T2D is high, and the occurrence of CRC is closely related to intestinal microflora. Metformin inhibits CRC in T2D patients by altering the abundance of gut microbiota or involving gut microbiota.…”