Abstract
Background: Traumatic brain injury (TBI) can be considered a "silent epidemic", causing
morbidity, disability, and mortality in all age cohorts. Therefore, a greater understanding of the underlying
pathophysiological intricate mechanisms and interactions with other organs and systems is
necessary to intervene not only in the treatment but also in the prevention of complications. In this
complex of reciprocal interactions, the complex brain-gut axis has captured a growing interest.
Scope: The purpose of this manuscript is to examine and systematize existing evidence regarding the
pathophysiological processes that occur following TBI and the influences exerted on these by the
brain-gut axis.
Literature Review: A systematic review of the literature was conducted according to the PRISMA
methodology. On the 8th of October 2021, two independent databases were searched: PubMed and
Scopus. Following the inclusion and exclusion criteria selected, 24 (12 from PubMed and 12 from
Scopus) eligible manuscripts were included in the present review. Moreover, references from the selected
articles were also updated following the criteria mentioned above, yielding 91 included manuscripts.
Discussion: Published evidence suggests that the brain and gut are mutually influenced through four
main pathways: microbiota, inflammatory, nervous, and endocrine.
Conclusion: These pathways are bidirectional and interact with each other. However, the studies conducted
so far mainly involve animals. An autopsy methodological approach to corpses affected by traumatic
brain injury or intestinal pathology could represent the keystone for future studies to clarify the
complex pathophysiological processes underlying the interaction between these two main systems.
Keywords:
traumatic brain injury, gut-brain axis, dysbiosis, dysautonomia, neuroinflammation, microbiota.
Graphical Abstract
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