The kynurenine pathway in major depressive disorder, bipolar disorder, and schizophrenia: a meta-analysis of 101 studies

  title={The kynurenine pathway in major depressive disorder, bipolar disorder, and schizophrenia: a meta-analysis of 101 studies},
  author={Wolfgang Marx and Amelia J McGuinness and Tetyana Rocks and Anu Ruusunen and Jasmine R. Cleminson and Adam J. Walker and Susana Gomes-da-Costa and Melissa M Lane and Marsal Sanches and Alexandre Paim Diaz and Ping-Tao Tseng and Pao-Yen Lin and Michael Berk and Gerard Clarke and Adrienne O'Neil and Felice Nellie Jacka and Brendon Stubbs and Andr{\'e} Ferrer Carvalho and Jo{\~a}o Quevedo and Jair C. Soares and Brisa S. Fernandes},
  journal={Molecular Psychiatry},
  pages={4158 - 4178}
The importance of tryptophan as a precursor for neuroactive compounds has long been acknowledged. The metabolism of tryptophan along the kynurenine pathway and its involvement in mental disorders is an emerging area in psychiatry. We performed a meta-analysis to examine the differences in kynurenine metabolites in major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SZ). Electronic databases were searched for studies that assessed metabolites involved in the kynurenine… 

The tryptophan catabolite or kynurenine pathway in major depressive and bipolar disorder: a systematic review and meta-analysis

The findings revealed that MDD/BD are accompanied by TRP depletion without IDO and TRYCAT pathway activation, and lowered TRP availability is probably the consequence of lowered serum albumin during the inflammatory response in affective disorders.

Quinolinic acid is associated with cognitive deficits in schizophrenia but not major depressive disorder

Results indicate that MDD and SZ are associated with dysregulation of the kynurenine pathway and Quinolinic acid might be specifically implicated in the pathophysiology of cognitive deficits in patients with SZ.

Is Poor Lithium Response in Individuals with Bipolar Disorder Associated with Increased Degradation of Tryptophan along the Kynurenine Pathway? Results of an Exploratory Study

The data indicate that lithium exerts anti-inflammatory effects by inhibiting indoleamine-2,3-dioxygenase (IDO)-1 activity and strengthens the assumption that the clinical drug response might be associated with biochemical processes.

The Role of Kynurenines in Cognitive Dysfunction in Bipolar Disorder

Future large-scale longitudinal studies are warranted to confirm the role of KYN metabolites in cognitive impairment in patients with BD and the possible therapeutic implications of this relationship.

Tryptophan Metabolism in Bipolar Disorder in a Longitudinal Setting

Investigation of tryptophan metabolism in bipolar disorder compared to controls (C), stratified by weight classes, in a longitudinal setting, indicates that tryPTophan, kynurenine, and IDO-1 activity may play a role in pathophysiology in BD but are not necessarily associated with clinical manifestations.

Associations Between the Kynurenine Pathway, Proinflammatory Cytokines, and Brain-Derived Neurotrophic Factor in Hospitalized Patients With Chronic Schizophrenia: A Preliminary Study

Investigating the relationships of the Kyn pathway with proinflammatory cytokines, BDNF, and psychiatric symptoms in patients with schizophrenia found no significant differences, although serum TNF-α levels showed no difference between the two groups.

Brain Versus Blood: A Systematic Review on the Concordance Between Peripheral and Central Kynurenine Pathway Measures in Psychiatric Disorders

Blood metabolite levels were associated with clinical symptoms and treatment response in psychiatric patients, as well as with observed neuroanatomical abnormalities and glial activity, and more research is needed to determine the validity of peripheral kynurenine metabolite assessment as proxy markers for CNS processes.

The tryptophan catabolite or kynurenine pathway in schizophrenia: meta-analysis reveals dissociations between central, serum, and plasma compartments

The central nervous system TRYCATs profile indicates neuroprotective, negative immunoregulatory and anti-inflammatory effects, and peripheral blood levels of TRYCats are dissociated from CNS findings except for a modest increase in serum IDO activity.



Serum kynurenic acid is reduced in affective psychosis

A post hoc comparison of patients divided into the categories of non-psychotic affective disorder, affective psychosis and psychotic disorder (non-affective) showed that the greatest decrease in KynA was in the affectives psychosis group relative to the other diagnostic groups.

Activation of the kynurenine pathway is associated with striatal volume in major depressive disorder

Kynurenic Acid in Schizophrenia: A Systematic Review and Meta-analysis

Overall, KYNA levels are increased in patients with schizophrenia, specifically within the central nervous system, and an improved understanding of KYNA in Patients with schizophrenia may contribute to the development of novel diagnostic approaches and therapeutic strategies.

The Metabolic Factor Kynurenic Acid of Kynurenine Pathway Predicts Major Depressive Disorder

This study provides a new diagnostic method to study MDD based on plasma KYNA level, and suggests that KYNA would be a potential biomarker in diagnosing depression patients.

The kynurenine pathway in schizophrenia and bipolar disorder

Kynurenine pathway in psychosis: evidence of increased tryptophan degradation

Evidence is provided for kynurenine pathway upregulation, specifically involving the first enzymatic step, in patients with major psychotic disorder, as well as a modest correlation was established between the tryptophan breakdown index and illness duration.

Peripheral and central levels of kynurenic acid in bipolar disorder subjects and healthy controls

These findings implicate brain-specific regulation of KYNA under physiological as well as under pathophysiological conditions and strengthen the previous observation of CSF KYNA as a biomarker in BD.