| 1. |
- Bay-Richter, Cecilie, et al.
(författare)
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A role for inflammatory metabolites as modulators of the glutamate N-methyl-D-aspartate receptor in depression and suicidality
- 2015
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Ingår i: Brain, behavior, and immunity. - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0889-1591 .- 1090-2139. ; 43, s. 110-117
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with depression and suicidality suffer from low-grade neuroinflammation. Proinflammatory cytokines activate indoleamine 2,3-dioxygenase, an initial enzyme of the kynurenine pathway. This pathway produces neuroactive metabolites, including quinolinic- and kynurenic acid, binding to the glutamate N-methyl-D-aspartate-receptor, which is hypothesized to be part of the neural mechanisms underlying symptoms of depression. We therefore hypothesized that symptoms of depression and suicidality would fluctuate over time in patients prone to suicidal behavior, depending on the degree of inflammation and kynurenine metabolite levels in the cerebrospinal fluid (CSF). Methods: We measured cytokines and kynurenine metabolites in CSF, collected from suicide attempters at repeated occasions over 2 years (total patient samples n = 143, individuals n = 30) and healthy controls (n = 36). The association between the markers and psychiatric symptoms was assessed using the Montgomery Asberg Depression Rating Scale and the Suicide Assessment Scale. Results: Quinolinic acid was increased and kynurenic acid decreased over time in suicidal patients versus healthy controls. Furthermore, we found a significant association between low kynurenic acid and severe depressive symptoms, as well as between high interleukin-6 levels and more severe suicidal symptoms. Conclusions: We demonstrate a long-term dysregulation of the kynurenine pathway in the central nervous system of suicide attempters. An increased load of inflammatory cytokines was coupled to more severe symptoms. We therefore suggest that patients with a dysregulated kynurenine pathway are vulnerable to develop depressive symptoms upon inflammatory conditions, as a result the excess production of the NMDA-receptor agonist quinolinic acid. This study provides a neurobiological framework supporting the use of NMDA-receptor antagonists in the treatment of suicidality and depression. (C) 2014 Elsevier Inc. All rights reserved.
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| 2. |
- Erhardt, Sophie, et al.
(författare)
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Connecting Inflammation with Glutamate Agonism in Suicidality
- 2013
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Ingår i: Neuropsychopharmacology. - : Nature Publishing Group: Open Access Hybrid Model Option A. - 0893-133X .- 1740-634X. ; 38:5, s. 743-752
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Tidskriftsartikel (refereegranskat)abstract
- The NMDA-receptor antagonist ketamine has proven efficient in reducing symptoms of suicidality, although the mechanisms explaining this effect have not been detailed in psychiatric patients. Recent evidence points towards a low-grade inflammation in brains of suicide victims. Inflammation leads to production of quinolinic acid (QUIN) and kynurenic acid (KYNA), an agonist and antagonist of the glutamatergic N-methyl-D-aspartate (NMDA) receptor, respectively. We here measured QUIN and KYNA in the cerebrospinal fluid (CSF) of 64 medication-free suicide attempters and 36 controls, using gas chromatography mass spectrometry and high-performance liquid chromatography. We assessed the patients clinically using the Suicide Intent Scale and the Montgomery Asberg Depression Rating Scale (MADRS). We found that QUIN, but not KYNA, was significantly elevated in the CSF of suicide attempters (Pandlt;0.001). As predicted, the increase in QUIN was associated with higher levels of CSF interleukin-6. Moreover, QUIN levels correlated with the total scores on Suicide Intent Scale. There was a significant decrease of QUIN in patients who came for follow-up lumbar punctures within 6 months after the suicide attempt. In summary, we here present clinical evidence of increased QUIN in the CSF of suicide attempters. An increased QUIN/KYNA quotient speaks in favor of an overall NMDA-receptor stimulation. The correlation between QUIN and the Suicide Intent Scale indicates that changes in glutamatergic neurotransmission could be specifically linked to suicidality. Our findings have important implications for the detection and specific treatment of suicidal patients, and might explain the observed remedial effects of ketamine. Neuropsychopharmacology (2013) 38, 743-752; doi:10.1038/npp.2012.248; published online 9 January 2013
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| 3. |
- Janelidze, Shorena, et al.
(författare)
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Altered chemokine levels in the cerebrospinal fluid and plasma of suicide attempters
- 2013
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Ingår i: Psychoneuroendocrinology. - : Elsevier. - 0306-4530 .- 1873-3360. ; 38:6, s. 853-862
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Tidskriftsartikel (refereegranskat)abstract
- Chemokines constitute a class of small inflammatory proteins that control the chemotaxis of leukocytes. They are also present in the central nervous system (CNS) and contribute to diverse physiological functions, such as the regulation of cell migration, axonal growth and neuronal survival. It is to date not known whether chemokines in the CNS are affected in psychiatric disorders. In this study, chemokine levels were measured in the cerebrospinal fluid (CSF) of 137 psychiatric patients in conjunction to a suicide attempt, and 43 healthy controls. A subgroup of patients (n = 42) was followed up with blood samples 12 years after the initial CSF collection, when they did not show suicidal behavior. The follow-up chemokine levels were compared to those of psychiatric patients (n = 17) who had never attempted suicide. Ultrasensitive chemokine multiplex immunoassay was used to quantify eotaxin-1 (CCL11), interferon gamma-induced protein-10 (IP-10, CXCL10), macrophage inflammatory protein-1 beta (MIP-1 beta, CCL4), monocyte chemotactic protein-1 (MCP-1, CCL2), MCP-4 (CCL13) and thymus and activation regulated chemokine (TARC, CCL17). Patients were diagnosed using DSM-III-R/DSM-IV, and assessed using the Comprehensive Psychopathological Rating Scale (CPRS), including subscales, and the Suicidal Intent Scale (SIS). CSF eotaxin-1, MIP-1 beta, MCP-1, MCP-4 and TARC were significantly lower in suicide attempters than in healthy controls. Low chemokine levels were specifically associated with psychotic symptoms and pain. In the samples collected at follow-up, TARC was significantly lower in suicide attempters compared to psychiatric patients who had never attempted suicide. We also found a positive correlation between blood TARC and brain-derived neurotrophic factor (BDNF) levels. Our study thus provides evidence of reduced chemokine levels in suicide attempters, both in the acute suicidal setting, and at long-term, compared to non-attempters. These results warrant future studies on the detailed neurobiological functions of chemokines in psychiatric patients. (C) 2012 Elsevier Ltd. All rights reserved.
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| 4. |
- Janelidze, Shorena, et al.
(författare)
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IL-8 is associated with anxiety in suicidal patients: genotypes and biological measures in cerebrospinal fluid and plasma
- 2015
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Ingår i: Acta Psychiatrica Scandinavica. - : Wiley. - 0001-690X .- 1600-0447. ; 131:4, s. 269-278
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Tidskriftsartikel (refereegranskat)abstract
- Objective Recent 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. Method We 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). Results Plasma 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. Conclusion We 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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| 5. |
- Lindqvist, Daniel, et al.
(författare)
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Interleukin-6 Is Elevated in the Cerebrospinal Fluid of Suicide Attempters and Related to Symptom Severity
- 2009
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Ingår i: BIOLOGICAL PSYCHIATRY. - : Elsevier BV. - 0006-3223 .- 1873-2402. ; 66:3, s. 287-292
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Tidskriftsartikel (refereegranskat)abstract
- Background: Depressive disorders are associated with immune system alterations that can be detected in the blood. Cytokine concentrations in cerebrospinal fluid (CSF) and their relationship to aspects of suicidality have previously not been investigated. Methods: We measured interleukin-1 beta interleukin-6 (IL-6), interleukin-8, and tumor necrosis factor-a (TNF-alpha) in CSF and plasma of suicide attempters (n = 63) and healthy control subjects (n = 47). Patients were classified according to diagnosis and violent or nonviolent suicide attempt. We evaluated suicidal ideation and depressive symptoms using the Suicide Assessment Scale and the Montgomery-Asberg Depression Rating Scale (MADRS). We also analyzed the relation between cytokines and monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in CSF, as well as the integrity of the blood-brain barrier as reflected by the CSF:serum albumin ratio. Results: IL-6 in CSF was significantly higher in suicide attempters than in healthy control subjects. Patients who performed violent suicide attempts displayed the highest IL-6. Furthermore, there was a significant positive correlation between MANS scores and CSF IL-6 levels in all patients. IL-6 and TNF-a correlated significantly with 5-HIAA and HVA in CSF, but not with MHPG. Cytokine levels in plasma and CSF were not associated, and patients with increased blood-brain barrier permeability did not exhibit elevated cytokine levels. Conclusions: We propose a role for CSF IL-6 in the symptomatology of suicidal behavior, possibly through mechanisms involving alterations of dopamine and serotonin metabolism.
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