Figure 5.

Biotin metabolism after bariatric surgery in mouse and human experiments. (A) Plasma biotin concentration of chow- or high-fat diet (HFD)-fed C57BL/6J mice with sham intervention (Sham) or bariatric surgery (Entero-gastro anastomosis, EGA).³⁵ Blood was collected 1 month after surgery for the HFD group and 3 months after surgery for the Chow group (**P value<0.01 Wilcoxon rank-sum test; Chow-Sham n=6, Chow-EGA n=8, HFD-Sham n=7, HFD-EGA n=6). (B) Mean abundances of biotin producers (bacteria with all biotin biosynthesis genes from pimelate and no biotin transport gene), biotin transporters (bacteria with no gene involved in biotin biosynthesis) and biotin producers+transporters (bacteria harbouring biotin biosynthesis and transport genes) in sham and EGA mice of the HFD group 30 days after surgery (*FDR<0.05 pairwise Wilcoxon rank-sum test). (C) Distribution of biotin deficiency groups between baseline and month 12 in 17 individuals of the Microbaria study stratified by surgery group (n=9, gastric banding; n=8, Roux-en-Y gastric bypass) according to the following thresholds:²⁸ deficiency (<200 ng/l), suboptimal levels (200-400 ng/l), optimal levels (>400 ng/l). P value=2.4x10-2 (bypass), P-value=1.1x10-1 (band); Fisher’s test. (D) Change of biotin producer and biotin transporter abundances (relative abundances multiplied by gene richness as a surrogate of microbial cell count to simulate QMP data) in 24 individuals of the Microbaria study stratified by surgery type (adjustable gastric banding, n=10; Roux-en-Y gastric, n=14) with metagenomics data at baseline, 1, 3, and 12 months after bariatric surgery (*P value<0.05; Wilcoxon signed-rank test). (E) Distribution of biotin deficiency groups at baseline (T0) and 12 months (T12) after bypass surgery in the BARICAN cohort (n=41; P value=2.0x10-2, Chi2 test). EGA, entero-gastro anastomosis; HFD, high-fat diet.