Alterations in tryptophan and purine metabolism in cocaine addiction: a metabolomic study

Background Mapping metabolic “signatures” can provide new insights into addictive mechanisms and potentially identify biomarkers and therapeutic targets. Objective We examined the differences in metabolites related to the tyrosine, tryptophan, purine, and oxidative stress pathways between cocaine-dependent subjects and healthy controls. Several of these metabolites serve as biological indices underlying the mechanisms of reinforcement, toxicity, and oxidative stress. Methods Metabolomic analysis was performed in 18 DSM-IV-diagnosed cocaine-dependent individuals with at least 2 weeks of abstinence and ten drug-free controls. Plasma concentrations of 37 known metabolites were analyzed and compared using a liquid chromatography electrochemical array platform. Multivariate analyses were used to study the relationship between severity of drug use [Addiction Severity Index (ASI) scores] and biological measures. Results Cocaine subjects showed significantly higher levels of n -methylserotonin ( p