Gastrointestinal Microbiome and Neurologic Injury

: Communication between the enteric nervous system (ENS) of the gastrointestinal (GI)
tract and the central nervous system (CNS) is vital for maintaining systemic homeostasis. Intrinsic
and extrinsic neurological inputs of the gut regulate blood flow, peristalsis, hormone release, and
immunological function. The health of the gut microbiome plays a vital role in regulating the overall
function and well-being of the individual. Microbes release short-chain fatty acids (SCFAs) that
regulate G-protein-coupled receptors to mediate hormone release, neurotransmitter release (i.e.,
serotonin, dopamine, noradrenaline, γ-aminobutyric acid (GABA), acetylcholine, and histamine),
and regulate inflammation and mood. Further gaseous factors (i.e., nitric oxide) are important in
regulating inflammation and have a response in injury. Neurologic injuries such as ischemic stroke,
spinal cord injury, traumatic brain injury, and hemorrhagic cerebrovascular lesions can all lead
to gut dysbiosis. Additionally, unfavorable alterations in the composition of the microbiota may
be associated with increased risk for these neurologic injuries due to increased proinflammatory
molecules and clotting factors. Interventions such as probiotics, fecal microbiota transplantation, and
oral SCFAs have been shown to stabilize and improve the composition of the microbiome. However,
the effect this has on neurologic injury prevention and recovery has not been studied extensively. The
purpose of this review is to elaborate on the complex relationship between the nervous system and
the microbiome and to report how neurologic injury modulates the status of the microbiome. Finally,
we will propose various interventions that may be beneficial in the recovery from neurologic injury. CLICK TO REVIEW

Keywords: gut microbiome; neurologic injury; enteric nervous system; emerging approaches