Molecular basis of tryptophan metabolism disorders associated with depression

Abstract Available data estimated that 350 million people suffer from depression worldwide. A growing body of evidence suggests that disorders of tryptophan metabolism may play a significant role in the development of depression. An elevated level of neurotoxic metabolites of tryptophan (3-hydroxykynurenine, quinolinic acid) and reduced concentration of the neuroprotective compound (kynurenic acid) may lead to neurodegeneration. Moreover, an increased risk of depression development may be associated with the occurrence of the same polymorphism localized in the gene encoding enzyme involved in the pathway of tryptophan metabolism. Additionally, patients with depression were characterized by disorders of enzymes activation of the pathway. However, the defects of tryptophan catabolites (TRYCATs) pathway can serve as diagnostic biomarkers in the future. Also, regulation of the process may allow the development of new, effective, and personalized antidepressant therapy.