The Effect of Linagliptin on the Microbiome of Diabetic ZDF Rats

Recent data suggest that the individual microbiome influences the pathology of type 2 diabetes (T2D). Linagliptin is a dipeptidyl peptidase 4 (DPP-4) inhibitor used for the treatment of T2D, which is excreted mainly via the bile. We investigated the microbiome of diabetic ZDF vs. normal rats and the effect of linagliptin on the gut bacterial composition over time. Diabetic ZDF and normal rats (two groups each, of six biological replicates) were treated with linagliptin 7.2 mg/kg qd or vehicle, in 5 ml/kg Natrosol 0.5%; faeces were collected at days 0, 3 and 7. The sequencing of microbial 16S rRNA amplicons was performed at CeMeT GmbH in Tübingen, to produce between 50000 and 75000 raw reads per library, at a read length of 2x250 bp. Preprocessing, import QC and quantification of reads assigned to specific operational taxonomic units (OTUs) were carried out using the MEGAN 6 toolbox. Between 14 k and 37 k raw reads were assigned to different bacterial phyla. We then used the Phyloseq package coupled with DESeq2 to determine significant changes in the abundance of OTUs between diabetic ZDF and normal animals, and changes over time in animals treated with linagliptin vs. vehicle. Between 20 and 27 OTUs (quantified at family level) significantly changed in untreated diabetic vs. healthy rats, in agreement with previously published studies. However, we found only weak to moderate changes in the linagliptin treated vs. untreated ZDF rats (i.e., 3 different bacterial families with significant changes in abundance after 7 days). No systematic changes in the biodiversity of the gut phyla could be attributed to linagliptin. This study provides new knowledge on how linagliptin affects the microbiome of diabetic ZDF vs. healthy rats. Some of the changes attributable to linagliptin agree with published studies on the beneficial effect of probiotics in diabetes. However, the observed changes in the microbiota after a short treatment with linagliptin are rather weak compared with the important differences seen in diabetic vs. nondiabetic animals. Disclosure S. Sayols: Employee; Self; Boehringer Ingelheim International GmbH. E. Simon: Employee; Self; Boehringer Ingelheim Pharmaceuticals, Inc. H. Klein: Employee; Self; Boehringer Ingelheim International GmbH. G.G. Leparc: Employee; Self; Boehringer Ingelheim International GmbH. M. Mark: Employee; Self; Boehringer Ingelheim International GmbH. G. Luippold: Employee; Self; Boehringer Ingelheim International GmbH. T. Klein: Employee; Self; Boehringer Ingelheim International GmbH, Boehringer Ingelheim International GmbH. Funding Boehringer Ingelheim; Eli Lilly and Company