Biological Plausibility of Using Plasma Amino Acid Profile Determination as a Potential Biomarker for Pediatric Patients with Mild Traumatic Brain Injuries.

Background: Amino acid biomarkers have a crucial influence on our understanding of brain injury mechanisms, and their plasma concentrations may indicate neurological damage and recovery patterns. Pediatric mild traumatic brain injury (mTBI) assessment particularly benefits from such molecular indicators, as clinical presentations can be subtle and variable. However, current diagnostic and prognostic tools lack reliable biochemical markers that can track the temporal evolution of injuries and recovery.

Methods: We conducted a prospective longitudinal cohort study involving 36 pediatric mTBI patients and 44 controls to characterize the temporal evolution of key amino acids and their derived indices. Blood samples were collected at 3, 6, 12, and 24 h and at 7, 14, and 28 days post-injury, with amino acids quantified using high-performance liquid chromatography.

Results: Our analysis revealed significant temporal changes in glutamate, glutamine, and glycine concentrations, with glutamate peaking at day 7 before declining, while glutamine showed steady increases throughout. The GLN/GLU ratio demonstrated an early excitatory imbalance followed by astrocytic compensation, and the GLX ratio indicated progressive recovery.

Conclusions: These patterns represent continuous neurochemical processes involving excitotoxicity and glial regulation, suggesting potential utility as biomarkers for mTBI diagnosis and monitoring. While further validation using larger cohorts is needed, these findings provide compelling evidence of the efficacy of using amino acid profiles to track pediatric mTBI progression and recovery.