Gut Microbiota in Diabetic Kidney Disease in Northern Thailand: A Preliminary Study

Abstract

Introduction: The risk factors that lead to the development of kidney damage in type 2 diabetic patients were known, such as poor glycemic control and poor blood pressure control. Data on clinical studies from Thailand and many countries show alteration in composition of gut microbiota in diabetes compared with non-diabetes. Studies from certain countries showed alteration in variation and composition of gut microbiota in patients with chronic kidney disease and end-stage kidney disease. There is no information in Thailand on the alteration in variation and composition of gut bacteria in patients with diabetic kidney disease. The main purpose of the study was to compare the difference in diversity and compositions of gut microbiota between three groups of patients: group A, type 2 diabetic patients with diabetic kidney disease (DN); group B, type 2 diabetic patients with normal kidney function (DM); and group C, hypertensive patients with normal kidney function who did not have diabetes (HT).

Methods: After screening and selecting by inclusion and exclusion criteria, 15 type 2 diabetes patients with chronic kidney disease were enrolled as the study participants (group A), 15 type 2 diabetic patients with normal kidney function were enrolled as the controls (group B), and 15 hypertensive patients with normal kidney function were enrolled as another control group (group C). Stool samples were sent for DNA extraction and 16S metagenome sequencing. For bioinformatic analysis, the Alpha-diversity metric, beta-diversity metric, and Principal Coordinate Analysis (PCoA) were applied. Taxonomy was developed for ASVs using the classify-sklearn native Bayes taxonomy classifier against the Greengenes 13_8 99% Operating taxonomy unit (OTUs) reference sequences. Statistical tests of alpha and beta diversity were performed using Kruskal-Wallis and PERMANNOVA.

Results: The study could not demonstrate the difference in community diversity of gut microbiota in all three groups. The Principal co-ordinate analysis (PCoA) based on Bray Curtis dissimilarity at the OTU level is the main method for the beta diversity analysis. PCoA showed no difference in gut microbiota composition among the three groups (p-value 0.544). PCoA using Jaccard, unweighted unifrac, and weighted unifrac distance analysis all of these methods also showed no difference in the microbial composition among the three groups.

Conclusion: The study could not find the differences in diversity and variation in compositions of gut microbiota in comparison among three groups of participants: type 2 diabetes mellitus with diabetic kidney disease, type 2 diabetes mellitus with normal kidney function, and hypertensive patients with normal kidney function. However, this study confirmed the features of gut microbiota compositions in type 2 diabetes mellitus with diabetic kidney disease from many previous studies, for example, the lower ratio of Firmicutes over Bacteroides in the diabetes group compared with the non-diabetes group. In addition, certain factors such as dietary profiles, lifestyle, and ethical investigation of the participants need to be considered in further study.