Arginine metabolomics in mood disorders.

Area of Science:

• Neuroscience
• Biochemistry
• Psychiatry

Background:

• Nitric oxide (NO) homeostasis is implicated in mood disorders.
• Direct NO measurement is challenging, necessitating alternative biomarker research.
• Alternative biomarkers may reflect NO synthesis alterations in mood disorders.

Purpose of the Study:

• To systematically review and synthesize evidence on alternative NO synthesis biomarkers in depressive and bipolar disorders.
• To investigate the association between biomarkers such as ADMA, SDMA, arginine, citrulline, and ornithine and mood disorders.

Main Methods:

• Comprehensive electronic database search from inception to June 30, 2023.
• Inclusion of 20 studies examining alternative NO biomarkers in mood disorder patients versus controls.
• Meta-analysis of standardized mean differences (SMDs) for biomarker concentrations.

Main Results:

• A trend towards higher asymmetric dimethylarginine (ADMA) in mood disorders was observed (p=0.072).
• Significant differences in ADMA were found in bipolar disorder (p<0.001) and European studies (p=0.02).
• Subgroup analyses revealed significant findings for symmetric dimethylarginine (SDMA), citrulline, and ornithine in specific populations and treatment groups.

Conclusions:

• Abnormal concentrations of ADMA, SDMA, citrulline, and ornithine are noted in subgroups of mood disorders, particularly bipolar disorder.
• These findings highlight the potential pathophysiological role of these biomarkers in mood disorders.
• Further research is warranted to elucidate their precise role and explore novel therapeutic targets.