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- Brundin, L., et al.
(författare)
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An enzyme in the kynurenine pathway that governs vulnerability to suicidal behavior by regulating excitotoxicity and neuroinflammation
- 2016
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Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Emerging evidence suggests that inflammation has a key role in depression and suicidal behavior. The kynurenine pathway is involved in neuroinflammation and regulates glutamate neurotransmission. In the cerebrospinal fluid (CSF) of suicidal patients, levels of inflammatory cytokines and the kynurenine metabolite quinolinic acid (QUIN), an N-methyl-D-aspartate receptor agonist, are increased. The enzyme amino-beta-carboxymuconate-semialdehyde-decarboxylase (ACMSD) limits QUIN formation by competitive production of the neuroprotective metabolite picolinic acid (PIC). Therefore, decreased ACMSD activity can lead to excess QUIN. We tested the hypothesis that deficient ACMSD activity underlies suicidal behavior. We measured PIC and QUIN in CSF and plasma samples from 137 patients exhibiting suicidal behavior and 71 healthy controls. We used DSM-IV and the Montgomery-Asberg Depression Rating Scale and Suicide Assessment Scale to assess behavioral changes. Finally, we genotyped ACMSD tag single nucleotide polymorphisms (SNPs) in 77 of the patients and 150 population-based controls. Suicide attempters had reduced PIC and a decreased PIC/QUIN ratio in both CSF (P<0.001) and blood (P=0.001 and P<0.01, respectively). The reductions of PIC in CSF were sustained over 2 years after the suicide attempt based on repeated measures. The minor C allele of the ACMSD SNP rs2121337 was more prevalent in suicide attempters and associated with increased CSF QUIN. Taken together, our data suggest that increased QUIN levels may result from reduced activity of ACMSD in suicidal subjects. We conclude that measures of kynurenine metabolites can be explored as biomarkers of suicide risk, and that ACMSD is a potential therapeutic target in suicidal behavior.
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- Janelidze, Shorena, et al.
(författare)
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Low IL-8 is associated with anxiety in suicidal patients: genetic variation and decreased protein levels
- 2015
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Ingår i: Acta Psychiatrica Scandinavica. - : Wiley: 12 months. - 0001-690X .- 1600-0447. ; 131:4, s. 269-278
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveRecent studies indicate that inflammation may play a role in the pathophysiology of suicidality. Interleukin-8 (IL-8) is a chemokine that in addition to its function in the immune system also exert neuroprotective properties. The involvement of this chemokine in neuropsychiatric conditions is incompletely known. MethodWe measured plasma and cerebrospinal fluid (CSF) IL-8, as well as the genotype frequency of a single nucleotide polymorphism (-251A/T, rs4073) in the promoter region of the IL8 gene, in suicide attempters (n=206) and healthy controls (n=578). ResultsPlasma and CSF levels of IL-8 were significantly lower in suicide attempters with anxiety than in healthy controls. IL-8 in both plasma and CSF correlated negatively with symptoms of anxiety. Compared with the population-based cohort, the IL-8-251T allele was more prevalent among female suicide attempters. Furthermore, suicide attempters carrying this allele showed more severe anxiety. This correlative study warrants further mechanistic studies on the effects of IL-8 in the central nervous system. ConclusionWe suggest that IL-8 might be involved in the biological mechanisms mediating resilience to anxiety. Thus, our findings highlight the chemokine IL-8 as a potential target for future development of anti-anxiety treatments and suicide prevention.
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- Schwieler, L., et al.
(författare)
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Electroconvulsive therapy suppresses the neurotoxic branch of the kynurenine pathway in treatment-resistant depressed patients
- 2016
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Ingår i: Journal of Neuroinflammation. - : Springer Science and Business Media LLC. - 1742-2094. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neuroinflammation is increasingly recognized as contributing to the pathogenesis of depression. Key inflammatory markers as well as kynurenic acid (KYNA) and quinolinic acid (QUIN), both tryptophan metabolites, have been associated with depressive symptoms and suicidality. The aim of the present study is to investigate the peripheral concentration of cytokines and tryptophan and kynurenine metabolites in patients with unipolar treatment-resistant depression before and after electroconvulsive therapy (ECT), the most effective treatment for depression. Methods: Cytokines in plasma from patients with major depressive disorder (MDD; n = 19) and healthy volunteers (n = 14) were analyzed with electrochemiluminescence detection. Tryptophan and kynurenine metabolites were detected with high-performance liquid chromatography (HPLC) and LC/MS. KYNA was analyzed in a second healthy control cohort (n = 22). Results: Patients with MDD had increased plasma levels of interleukin (IL)-6 compared to healthy volunteers (P < 0.05). We also found an altered kynurenine metabolism in these patients displayed by decreased plasma levels of KYNA (P < 0.0001) as well as a significantly increased QUIN/KYNA ratio (P < 0.001). Plasma levels of tryptophan, kynurenine, and QUIN did not differ between patients and controls. Treatment with ECT was associated with a significant decrease in the plasma levels of tryptophan (P < 0.05), kynurenine (P < 0.01), and QUIN (P < 0.001), whereas plasma levels of KYNA did not change. The QUIN/KYNA ratio was found to significantly decrease in ECT-treated patients (P < 0.05). There was a significant inverse correlation between symptom severity and kynurenine levels at baseline (r = -0.67, P = 0.002). Conclusions: This study confirms an imbalanced kynurenine pathway in MDD supporting the hypothesis of a netstimulation of N-methyl-D-aspartic acid (NMDA) receptors in the disorder. Treatment with ECT profoundly decreased QUIN, an NMDA-receptor agonist previously suggested to be implicated in the pathogenesis of depression, an effect that might have bearing for the good clinical outcome of ECT.
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- Ventorp, Filip, et al.
(författare)
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The CD44 ligand hyaluronic acid is elevated in the cerebrospinal fluid of suicide attempters and is associated with increased blood-brain barrier permeability.
- 2016
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Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 1573-2517 .- 0165-0327. ; 193, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- The glycosaminoglycan hyaluronic acid (HA) is an important component of the extracellular matrix (ECM) in the brain. CD44 is a cell adhesion molecule that binds to HA in the ECM and is present on astrocytes, microglia and certain neurons. Cell adhesion molecules have been reported to be involved in anxiety and mood disorders. CD44 levels are decreased in the cerebrospinal fluid (CSF) of depressed individuals, and the CD44 gene has been identified in brain GWAS studies as a possible risk gene for suicidal behavior.
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