Urinary metabolome dynamics in ¹³C-labeled mice.

Area of Science:

• Metabolomics
• Systems Biology
• Isotope Tracing

Background:

• Metabolic flux analysis typically uses specific labeled precursors and LC-HRMS.
• Targeted approaches limit the scope of metabolic pathway investigation.

Purpose of the Study:

• To investigate whole metabolome dynamics using a novel approach of a fully ¹³C-enriched diet in mice.
• To assess the feasibility and outcomes of long-term whole-body isotope labeling.

Main Methods:

• Mice were fed a diet fully enriched in ¹³C for six weeks.
• Urine samples were collected daily and analyzed using LC-HRMS and isotope tracing.
• Comparative analysis was performed against control mice fed an unenriched diet.

Main Results:

• Mice tolerated the ¹³C-enriched diet, showing normal growth.
• LC-HRMS identified 238 metabolites, with ¹³C labeling profiles monitored over 39 days.
• Urine labeling reached >90% ¹³C after 22 days, but incorporation kinetics varied significantly between metabolites.

Conclusions:

• A diet fully labeled with ¹³C is well-tolerated by mice over six weeks.
• This whole-body labeling approach reveals dynamic metabolome information in mammals via urine analysis.
• The study provides comprehensive metabolic pathway insights, surpassing limitations of targeted fluxomic studies.