Evaluation of hypoglycemic effect, safety and immunomodulation of Prevotella copri in mice

The gut bacterium Prevotella copri ( P. copri) has been shown to lower blood glucose levels in mice as well as in healthy humans, and is a promising candidate for a next generation probiotic aiming at prevention or treatment of obesity and type 2 diabetes. In this study the hypoglycemic effect of live P. copri was confirmed in mice and pasteurization of P. copri was shown to further enhance its capacity to improve glucose tolerance. The safety of live and pasteurized P. copri was evaluated by a 29-day oral toxicity study in mice. P. copri did not induce any adverse effects on body growth. General examination of the mice, gross pathological and histological analysis showed no abnormalities of the vital organs. Though relative liver weights were lower in the pasteurized (4.574 g ± 0.096) and live (4.347 g ± 0.197) P. copri fed groups than in the control mice (5.005 g ± 0.103) (p = 0.0441 and p = 0.0147 respectively), no liver biochemical marker aberrations were detected. Creatinine serum levels were significantly lower in mice fed with live (p = 0.001) but not pasteurized (p = 0.163) P. copri compared to those of control mice. Haematological parameter analysis and low plasma Lipopolysaccharide Binding Protein (LBP) levels ruled out systemic infection and inflammation. Immunomodulation capacity by P. copri as determined by blood plasma cytokine analysis was limited and gut colonisation occurred in only one of the 10 mice tested. Taken together, no major adverse effects were detected in P. copri treated groups compared to controls.