Figure 1.
Schematic of the study design.
Subjects were studied at 4 time points: (i) at baseline on metformin, (ii) 7 days after stopping metformin, (iii) when fasting blood glucose (FBG) had risen by 25% after stopping metformin, and (iv) when FBG returned to baseline levels after restarting the metformin.
Table 1.
Glucose and peptide assays.
Table 2.
Disposition and Baseline Demographics of the Subjects with T2DM.
Figure 2.
Postprandial glucose profiles.
Mean plasma glucose profiles during the postprandial period of the day (left) and weighted mean AUC (± 95% confidence interval) over 0–4, 4–8 and 0–12 h (right). Data points are coded for visit number where: black circles = Visit 1; white circles = Visit 2; white triangles = Visit 3; black triangles = Visit 4.
Figure 3.
Bile acid concentrations (mean ± 95% confidence interval) in serum (AUC 4–8 h) (top), faeces (middle) and eluted bile from Entero-Test string (bottom). Bile acids: C = Cholic; CDC = Chenodeoxycholic; DC = Deoxycholic; LC = Lithocholic; Prim = Primary; Second = Secondary.
Figure 4.
Postprandial serum bile acid profiles.
Mean serum total, primary and secondary bile acid concentration profiles over 12(left) and weighted mean AUC (± 95% confidence interval) over 0–4, 4–8 and 0–12 h (right). Data point shape and color represent different visits as described in Figure 2.
Figure 5.
Mean total (top) and active (bottom) plasma GLP-1 profiles over 12 h (left) and weighted mean AUC (± 95% confidence interval) over 0–4, 4–8 and 0–12 h (right). Data point shape and color represent different visits as described in Figure 2.
Figure 6.
Mean plasma PYY mean profiles over 12(left) and weighted mean AUC (± 95% confidence interval) over 0–4, 4–8 and 0–12 h (right). Data point shape and color represent different visits as described in Figure 2.
Figure 7.
Relative abundance of microbial species across stool samples based on 16s rRNA V1–V3 region analysis.
For each subject (S#), samples are ordered from first to last time points. Bacterial abundances determined at the phylum level are shown, although further analyses were completed at all intermediate taxonomic levels to genus.
Figure 8.
Principal coordinate analysis of microbiome beta diversity.
QIIME software [31] was used to generate PCoA plots of beta (inter-sample) diversity of samples which are colored by subject. Different PCoA axes plots shown are: (a) PCA1 vs PCA2; (b) PCA3vs PCA1, and (c) PCA3 vs PCA2.
Figure 9.
Box plots of bacterial genus On-metformin versus Off-metformin.
Plots are shown for the bacterial genera (a) Adlercreutzia, (b) Firmicute (other), (c) Eubacterium and (d) SMB53. Bacterial adjusted P values used the FDR correction as described in the Methods.
Table 3.
Gut microbiome analysis On- and Off-metformin.
Figure 10.
Correlations of bacterial species abundance with bile acids and PYY.
Values are proportional changes in bacteria from baseline plotted for (a) Bacteriodetes vs cholic acid plus conjugates, (b) Firmicutes vs cholic acid plus conjugates, (c) Bacteriodetes vs PYY and (d) Firmicutes vs PYY. Adjusted P values used the FDR correction as described in the Methodology. Data point shape and color represent different visits as in Figure 2.