Mapping small metabolite changes after traumatic brain injury using AP-MALDI MSI.

Area of Science:

• Neuroscience
• Metabolomics
• Biochemistry

Background:

• Traumatic brain injury (TBI) causes significant metabolic alterations impacting injury progression and outcomes.
• Understanding regional metabolic changes is crucial for TBI research due to injury heterogeneity.
• Mass spectrometry imaging (MSI) offers a powerful method for spatial analysis of metabolites in brain tissue.

Purpose of the Study:

• To characterize the impact of TBI on regional small metabolite changes in the brain.
• To apply an innovative targeted atmospheric pressure-MALDI MSI approach for detailed metabolic profiling.
• To identify specific metabolites and brain regions affected by TBI.

Main Methods:

• Applied targeted atmospheric pressure-MALDI MSI to analyze mouse brains 21 days post-TBI.
• Utilized an extensive list of validated metabolites, including standards with 2,5-dihydroxybenzoic acid (DHB).
• Performed whole-brain and regional (ipsilateral vs. contralateral hemisphere, thalamus) analyses.

Main Results:

• Identified four metabolites (alanine, lysine, histidine, inosine) with higher abundance in TBI versus sham mice.
• Observed increased levels of lysine, histidine, and inosine in the hemisphere ipsilateral to the injury.
• Detected increased arginine, lysine, histidine, and inosine, with decreased glutamic acid and N-acetylaspartic acid in the ipsilateral thalamus compared to the contralateral side.

Conclusions:

• High-resolution imaging mass spectrometry is effective for identifying region-specific metabolic changes post-TBI.
• Specific metabolite alterations in TBI correlate with injury location and severity.
• These findings advance the understanding of metabolic pathways involved in TBI evolution.