Association between gut microbiota and diabetic nephropathy: a two-sample mendelian randomization study.

Background: Observational studies have demonstrated the alterations of gut microbiota composition in diabetic nephropathy (DN), however, the correlation between gut microbiota and DN remains unclear.

Methods: A two-sample Mendelian randomization (MR) analysis was designed to estimate the association between gut microbiota and DN. The summary statistics of gut microbiota from phylum level to genus level were obtained from a large-scale, genome-wide association study involving 18,340 individuals, and the data at the species level was derived from the study of TwinsUK Registry, including 1126 twin pairs. The summary statistics of DN were originated from the latest release data of FinnGen (R7, 299623 participants). The MR estimation was calculated using inverse variance weighted, weighted median, MR-Egger regression, and MR-PRESSO. Heterogeneity was assessed using Cochrane's Q test.

Results: Inverse variance weighted results indicated that the order Bacteroidetes and its corresponding class and phylum [odds ratio (OR), 1.58; 95% confidence interval (CI), 1.15-2.17], the family Verrucomicrobiaceae and its corresponding class and order (OR, 1.46; 95% CI, 1.14-1.87), the genera Akkermansia (OR, 1.46; 95% CI, 1.14-1.87) and Catenibacterium (OR, 1.33; 95% CI, 1.07-1.66) might be associated with a higher risk of DN; whereas the genera Coprococcus2 (OR, 0.68; 95% CI, 0.51-0.91) and Eubacterium_coprostanoligenes_group (OR, 0.69; 95% CI, 0.52-0.92) might play protective roles in DN.

Conclusions: This MR study suggested that several gut bacteria were potentially associated with DN, further studies are required to validate these findings.