AUTHOR=Yi Sue Y. , Pirasteh Ali , Wang James , Bradshaw Tyler , Jeffery Justin J. , Barnett Brian R. , Stowe Nicholas A. , McMillan Alan B. , Vivas Eugenio I. , Rey Federico E. , Yu John-Paul J. TITLE=18F-SynVesT-1 PET/MR Imaging of the Effect of Gut Microbiota on Synaptic Density and Neurite Microstructure: A Preclinical Pilot Study JOURNAL=Frontiers in Radiology VOLUME=2 YEAR=2022 URL=https://www.frontiersin.org/journals/radiology/articles/10.3389/fradi.2022.895088 DOI=10.3389/fradi.2022.895088 ISSN=2673-8740 ABSTRACT=

The gut microbiome profoundly influences brain structure and function. The gut microbiome is hypothesized to play a key role in the etiopathogenesis of neuropsychiatric and neurodegenerative illness; however, the contribution of an intact gut microbiome to quantitative neuroimaging parameters of brain microstructure and function remains unknown. Herein, we report the broad and significant influence of a functional gut microbiome on commonly employed neuroimaging measures of diffusion tensor imaging (DTI), neurite orientation dispersion and density (NODDI) imaging, and SV2A 18F-SynVesT-1 synaptic density PET imaging when compared to germ-free animals. In this pilot study, we demonstrate that mice, in the presence of a functional gut microbiome, possess higher neurite density and orientation dispersion and decreased synaptic density when compared to age- and sex-matched germ-free mice. Our results reveal the region-specific structural influences and synaptic changes in the brain arising from the presence of intestinal microbiota. Further, our study highlights important considerations for the development of quantitative neuroimaging biomarkers for precision imaging in neurologic and psychiatric illness.