Glioma induced alterations in fecal short-chain fatty acids and neurotransmitters.

Aim: To explore fecal short-chain fatty acids and neurotransmitter alterations in a mouse-glioma model and glioma patients. Methods: Liquid chromatography-mass spectrometry and 16S rRNA-sequencing from fecal samples were performed to measure metabolite levels and taxa abundance in mice/humans. Mice underwent GL261 implantation with/without temozolomide. Glioma patients were compared with healthy controls. Results: Glioma altered several short-chain fatty acids and neurotransmitter levels. Reduced 5-hydroxyindoleaceic acid and norepinephrine levels were seen in mice and humans. Interestingly, temozolomide treatment abrogates the effects of glioma on fecal metabolites. Conclusion: Our findings demonstrate the interplay between glioma and the gut-brain axis. Further work is required to identify pathways within the gut-brain axis by which glioma influences and promotes the modulation of fecal metabolites and microbiome.