The altered TBI fecal microbiome is stable and functionally distinct

Area of Science:

• Microbiology
• Neuroscience
• Gastroenterology

Background:

• Traumatic brain injury (TBI) can lead to chronic health issues, including alterations in the gut microbiome.
• Recent studies indicate both acute and long-term dysbiosis in the gastrointestinal tract following TBI, with significant changes in microbial composition and function.

Purpose of the Study:

• To evaluate the metagenomic stability of the TBI-associated fecal microbiome (FMB) over time.
• To identify specific bacterial genes, pathways, and core microbiota responsible for the functional consequences of TBI-induced FMB dysbiosis.

Main Methods:

• Longitudinal analysis of fecal samples (2015 and 2020) from TBI patients using custom qPCR arrays for metagenomic stability.
• Metatranscriptomic analysis to identify differentially expressed bacterial genes and biochemical pathways.
• Bioinformatic analysis to compare microbial composition and functional profiles between TBI patients and healthy controls.

Main Results:

• The TBI fecal microbiome (FMB) demonstrated remarkable metagenomic stability between 2015 and 2020.
• Significant differences in microbial abundance were observed, with genera like Bacteroides caccae and Collinsella spp. being notably altered in TBI patients compared to controls.
• Functional analysis revealed distinct metabolic pathway profiles, with TBI FMB showing altered amino acid metabolism, energy source usage, and cell wall synthesis compared to controls.

Conclusions:

• The fecal microbiome in TBI patients remains stably dysbiotic for years post-injury.
• Specific bacterial genera and functional pathways are consistently altered, contributing to the long-term consequences of TBI.
• These findings highlight the gut microbiome as a potential therapeutic target for managing chronic TBI sequelae.