Refractory diet-dependent changes in neural microstructure: Implications for microstructural endophenotypes of...

Area of Science:

• Neuroscience
• Microstructure Imaging
• Gut Microbiome Research

Background:

• Dietary manipulation influences gut microbiome populations.
• Gut microbiome alterations can induce diet-dependent changes in white matter microstructure.

Purpose of the Study:

• To investigate the durability and recoverability of diet-induced white matter microstructural alterations.
• To examine the long-term effects of specific diets on brain white matter.

Main Methods:

• A crossover experimental design was used with post-weaned male rats assigned to four diets (control, high-fat, high-fiber, high-protein).
• Brains were imaged ex-vivo using diffusion tensor imaging (DTI) before and after diet crossover and resumption of a normal diet.
• Tract-based spatial statistics (TBSS) and region-of-interest (ROI) analyses were performed on DTI metrics (FA, TR, RD).

Main Results:

• High-fat diet induced voxel-wise differences in fractional anisotropy (FA).
• Diet crossover resulted in new FA and trace diffusion (TR) changes in different brain regions.
• High-fiber diet crossover led to widespread diffusion tensor changes, while high-protein diet showed decreased radial diffusivity (RD) upon returning to a normal diet.

Conclusions:

• Diet-induced changes in neural microstructure are often durable and unrecoverable after resuming a normal diet.
• Resuming a normal diet can, in some cases, lead to further unanticipated changes in white matter microstructure.