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Wang Z, Huang S, Li L, Wen Y, Shang D. Kynurenine metabolite changes in individuals with alcohol use disorder: A systematic review and meta-analysis. Drug Alcohol Depend 2023; 249:110821. [PMID: 37327508 DOI: 10.1016/j.drugalcdep.2023.110821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/19/2023] [Accepted: 06/05/2023] [Indexed: 06/18/2023]
Abstract
OBJECTIVE Growing evidence suggests an abnormal metabolism of kynurenine in individuals with alcohol use disorder (AUD). This systematic review and meta-analysis was aimed at assessing the possible differences in kynurenine metabolites between individuals with AUD and controls. METHODS We searched PubMed, Embase, and Web of Science databases and included any clinical studies comparing the peripheral blood levels of at least one metabolite, between individuals with AUD and controls without AUD. Random-effects meta-analyses were conducted to generate pooled standardized mean differences (SMD). Subgroup analyses and meta-regression analyses were conducted. RESULTS A total of seven eligible studies with 572 participants were included. The peripheral blood levels of kynurenine (SMD = 0.58; p = 0.004) along with the ratio of kynurenine and tryptophan (SMD = 0.73; p = 0.002) were higher in individuals with AUD, while kynurenic acid levels (SMD = -0.81; p = 0.003) were reduced in individuals with AUD compared to controls. The peripheral blood levels of tryptophan along with the ratio of kynurenic acid and kynurenine were unaltered. Subgroup analyses confirmed these results. CONCLUSION Our results suggested a shift in the tryptophan metabolism to the kynurenine pathway and a down-regulation of the potentially neuroprotective kynurenic acid in individuals with AUD.
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Affiliation(s)
- Zhanzhang Wang
- Department of Pharmacy, the Affiliated Brain Hospital of Guangzhou Medical University, 36 Mingxin Road, Guangzhou510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou510370, China
| | - Shanqing Huang
- Department of Pharmacy, the Affiliated Brain Hospital of Guangzhou Medical University, 36 Mingxin Road, Guangzhou510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou510370, China
| | - Lu Li
- Department of Pharmacy, the Affiliated Brain Hospital of Guangzhou Medical University, 36 Mingxin Road, Guangzhou510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou510370, China
| | - Yuguan Wen
- Department of Pharmacy, the Affiliated Brain Hospital of Guangzhou Medical University, 36 Mingxin Road, Guangzhou510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou510370, China.
| | - Dewei Shang
- Department of Pharmacy, the Affiliated Brain Hospital of Guangzhou Medical University, 36 Mingxin Road, Guangzhou510370, China; Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou510370, China.
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Morcuende A, Navarrete F, Nieto E, Manzanares J, Femenía T. Inflammatory Biomarkers in Addictive Disorders. Biomolecules 2021; 11:biom11121824. [PMID: 34944470 PMCID: PMC8699452 DOI: 10.3390/biom11121824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/23/2021] [Accepted: 11/30/2021] [Indexed: 12/21/2022] Open
Abstract
Substance use disorders are a group of diseases that are associated with social, professional, and family impairment and that represent a high socio-economic impact on the health systems of countries around the world. These disorders present a very complex diagnosis and treatment regimen due to the lack of suitable biomarkers supporting the correct diagnosis and classification and the difficulty of selecting effective therapies. Over the last few years, several studies have pointed out that these addictive disorders are associated with systemic and central nervous system inflammation, which could play a relevant role in the onset and progression of these diseases. Therefore, identifying different immune system components as biomarkers of such addictive disorders could be a crucial step to promote appropriate diagnosis and treatment. Thus, this work aims to provide an overview of the immune system alterations that may be biomarkers of various addictive disorders.
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Affiliation(s)
- Alvaro Morcuende
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Avda. de Ramón y Cajal s/n, San Juan de Alicante, 03550 Alicante, Spain; (A.M.); (F.N.); (E.N.); (J.M.)
| | - Francisco Navarrete
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Avda. de Ramón y Cajal s/n, San Juan de Alicante, 03550 Alicante, Spain; (A.M.); (F.N.); (E.N.); (J.M.)
- Red Temática de Investigación Cooperativa en Salud (RETICS), Red de Trastornos Adictivos, Instituto de Salud Carlos III, MICINN and FEDER, 28029 Madrid, Spain
| | - Elena Nieto
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Avda. de Ramón y Cajal s/n, San Juan de Alicante, 03550 Alicante, Spain; (A.M.); (F.N.); (E.N.); (J.M.)
| | - Jorge Manzanares
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Avda. de Ramón y Cajal s/n, San Juan de Alicante, 03550 Alicante, Spain; (A.M.); (F.N.); (E.N.); (J.M.)
- Red Temática de Investigación Cooperativa en Salud (RETICS), Red de Trastornos Adictivos, Instituto de Salud Carlos III, MICINN and FEDER, 28029 Madrid, Spain
| | - Teresa Femenía
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Avda. de Ramón y Cajal s/n, San Juan de Alicante, 03550 Alicante, Spain; (A.M.); (F.N.); (E.N.); (J.M.)
- Red Temática de Investigación Cooperativa en Salud (RETICS), Red de Trastornos Adictivos, Instituto de Salud Carlos III, MICINN and FEDER, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-965-919-553
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Adams C, Conigrave JH, Lewohl J, Haber P, Morley KC. Alcohol use disorder and circulating cytokines: A systematic review and meta-analysis. Brain Behav Immun 2020; 89:501-512. [PMID: 32805393 DOI: 10.1016/j.bbi.2020.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/30/2020] [Accepted: 08/07/2020] [Indexed: 12/29/2022] Open
Abstract
There has been emerging interest in the role of the immune system in the pathophysiology of alcohol use disorder (AUD) given alcohol consumption stimulates immune cells to secrete peripheral pro- and anti-inflammatory cytokines. We conducted a systematic review and meta-analysis to determine whether an abnormal inflammatory cytokine profile exists in AUD patients compared to controls and whether cytokine levels were correlated with behavioural and psychiatric variables. Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-analyses) guidelines, a comprehensive search of electronic databases (MEDLINE, EMBASE, Web of Science Core Collection and the Cochrane Library) was conducted, for AUD-related terms in combination with cytokine-related terms. Patients had to meet established criteria for AUD and be compared with healthy controls. A critical appraisal was completed using the Newcastle-Ottawa Scale. Twenty-four papers met the inclusionary criteria with 46 serum or plasma cytokines measured without immune stimulation whereby 17 studies had sufficient data for inclusion in the meta-analysis. Collectively, AUD patients had greater cytokine concentrations than control patients g = 0.85 [ 95% CI 0.42, 1.29]. Differences in cytokine concentrations between AUD patients and controls varied within-study by stage of illness (R(2)2 = 19.56%). The greatest differences were reported when AUD patients were engaging in active drinking g = 0.96 [0.49, 1.43] or were in alcohol withdrawal g = 1.25 [0.71, 1.80]. Baseline findings were moderated within and between studies by cytokine identity R(2)2 = 51.10%; R(3)2 = 44.89%. Cytokine concentrations were not significantly correlated with self-reported craving for alcohol, but were with alcohol consumption r = 0.22 [-0.05, 0.46]. The relationship between cytokine concentration and consumption was moderated by cytokine identity (R(2)2 = 100.00%; R(3)2 = 100.00%), and sample age (R(2)2 = 0.00%; R(3)2 = 95.76%). There is sufficient evidence to support the presence of an abnormal circulating cytokine profile in AUD which may vary with respect to the different stages of AUD illness.
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Affiliation(s)
- Claire Adams
- University of Sydney, Faculty of Medicine and Health, Central Clinical School, Discipline of Addiction Medicine, New South Wales, Australia
| | - James H Conigrave
- University of Sydney, Faculty of Medicine and Health, Central Clinical School, Discipline of Addiction Medicine, Centre of Research Excellence in Indigenous Health and Alcohol, New South Wales, Australia
| | - Joanne Lewohl
- School of Medical Science, Griffith University, Gold Coast, QLD, Australia
| | - Paul Haber
- University of Sydney, Faculty of Medicine and Health, Central Clinical School, Discipline of Addiction Medicine, New South Wales, Australia; Drug Health Services, Royal Prince Alfred Hospital, NSW, Australia
| | - Kirsten C Morley
- University of Sydney, Faculty of Medicine and Health, Central Clinical School, Discipline of Addiction Medicine, New South Wales, Australia.
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Loftis JM, Valerio J, Taylor J, Huang E, Hudson R, Taylor-Young P, Chang M, Ho SB, Dieperink E, Miranda JL, Hauser P. S100B and Inflammatory Cytokine Levels in Blood as Potential Markers of Blood-Brain Barrier Damage and Psychiatric Impairment in Comorbid Hepatitis C Viral Infection and Alcohol Use Disorder. Alcohol Clin Exp Res 2018; 42:10.1111/acer.13796. [PMID: 29953169 PMCID: PMC6310679 DOI: 10.1111/acer.13796] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 05/15/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Hepatitis C virus (HCV) infection and alcohol use disorder (AUD) both adversely affect the immune system resulting in alterations in immune cell signaling and inflammatory processes. The aim of this study was to investigate how comorbid AUD contributes to abnormalities in inflammatory mediators and psychiatric impairments in adults with HCV. METHODS Alcohol use, mood, and inflammatory factors were evaluated at 3 time points (baseline, week 4, and week 12) in Veterans with HCV, with (n = 42) and without (n = 13) comorbid AUD. Peripheral indices of immune activation, blood-brain barrier (BBB) damage (S100 calcium-binding protein B [S100B]), liver function, and viral load were measured using immunoassays and polymerase chain reaction assays. RESULTS Comorbid AUD was associated with increased symptoms of depression and anxiety, elevated levels of liver enzymes, and altered expression of inflammatory factors. Alcohol consumption was positively correlated with the severity of psychiatric symptoms. Univariate analysis identified significant group differences in interleukin (IL)-8 (p = 0.006), IL-10 (p = 0.03), and S100B (p = 0.048), with increased levels in participants with AUD, which persisted over time despite reductions in alcohol use and no significant change in HCV viral load. Statistically significant effects of study group or time were not found for the other immune factors assessed. Exploratory receiver operating characteristic curve analysis evaluated the ability of IL-8, IL-10, and S100B to differentiate between levels of alcohol consumption and generated biomarker cutoff values used to identify low risk and unhealthy alcohol use groups. CONCLUSIONS These results demonstrate that HCV and comorbid AUD are associated with greater psychiatric impairments, potentially resulting from increased inflammation, dysregulated cytokine expression, and compromised BBB function. Alcohol-induced BBB damage may increase the risk of neuropathological consequences within the context of chronic HCV infection.
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Affiliation(s)
- Jennifer M. Loftis
- Research & Development Service, VA Portland Health Care System, Portland, OR, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Juno Valerio
- Research & Development Service, VA Portland Health Care System, Portland, OR, USA
| | - Jonathan Taylor
- Research & Development Service, VA Portland Health Care System, Portland, OR, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Elaine Huang
- Research & Development Service, VA Portland Health Care System, Portland, OR, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, USA
| | - Rebekah Hudson
- Research & Development Service, VA Portland Health Care System, Portland, OR, USA
| | - Patricia Taylor-Young
- Nursing Research Department, VA Portland Health Care System, Portland, OR, USA
- School of Nursing, Oregon Health & Science University, Portland, OR, USA
| | - Michael Chang
- Gastroenterology, VA Portland Health Care System, Portland, OR, USA
- Internal Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Samuel B. Ho
- VA San Diego Healthcare System, San Diego, CA, USA
- Department of Medicine, University of California San Diego, San Diego, CA, USA
| | - Eric Dieperink
- Minneapolis VA Healthcare System, Minneapolis, MN, USA
- Department of Psychiatry, University of Minnesota School of Medicine, Minneapolis, MN, USA
| | - Juan Luis Miranda
- VA Long Beach Health Care System, 5901 E 7th St, Long Beach, CA, USA
| | - Peter Hauser
- VA Long Beach Health Care System, 5901 E 7th St, Long Beach, CA, USA
- Department of Psychiatry and Human Behavior, University of California-Irvine, Irvine, CA, USA
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
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Zahr NM. Peripheral TNFα elevations in abstinent alcoholics are associated with hepatitis C infection. PLoS One 2018; 13:e0191586. [PMID: 29408932 PMCID: PMC5800541 DOI: 10.1371/journal.pone.0191586] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/08/2018] [Indexed: 12/31/2022] Open
Abstract
Substantial evidence supports the view that inflammatory processes contribute to brain alterations in HIV infection. Mechanisms recently proposed to underlie neuropathology in Alcohol Use Disorder (AUD) include elevations in peripheral cytokines that sensitize the brain to the damaging effects of alcohol. This study included 4 groups: healthy controls, individuals with AUD (abstinent from alcohol at examination), those infected with HIV, and those comorbid for HIV and AUD. The aim was to determine whether inflammatory cytokines are elevated in AUD as they are in HIV infection. Cytokines showing group differences included interferon gamma-induced protein 10 (IP-10) and tumor necrosis factor α (TNFα). Follow-up t-tests revealed that TNFα and IP-10 were higher in AUD than controls but only in AUD patients who were seropositive for Hepatitis C virus (HCV). Specificity of TNFα and IP-10 elevations to HCV infection status was provided by correlations between cytokine levels and HCV viral load and indices of liver integrity including albumin/globulin ratio, fibrosis scores, and AST/platelet count ratio. Because TNFα levels were mediated by HCV infection, this study provides no evidence for elevations in peripheral cytokines in "uncomplicated", abstinent alcoholics, independent of liver disease or HCV infection. Nonetheless, these results corroborate evidence for elevations in IP-10 and TNFα in HIV and for IP-10 levels in HIV+HCV co-infection.
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Affiliation(s)
- Natalie M. Zahr
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States of America
- Neuroscience Department, SRI International, Menlo Park, CA, United States of America
- * E-mail:
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Warden A, Erickson E, Robinson G, Harris RA, Mayfield RD. The neuroimmune transcriptome and alcohol dependence: potential for targeted therapies. Pharmacogenomics 2016; 17:2081-2096. [PMID: 27918243 DOI: 10.2217/pgs-2016-0062] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Transcriptome profiling enables discovery of gene networks that are altered in alcoholic brains. This technique has revealed involvement of the brain's neuroimmune system in regulating alcohol abuse and dependence, and has provided potential therapeutic targets. In this review, we discuss Toll-like-receptor pathways, hypothesized to be key players in many stages of the alcohol addiction cycle. The growing appreciation of the neuroimmune system's involvement in alcoholism has also led to consideration of crucial roles for glial cells, including astrocytes and microglia, in the brain's response to alcohol abuse. We discuss current knowledge and hypotheses on the roles that specific neuroimmune cell types may play in addiction. Current strategies for repurposing US FDA-approved drugs for the treatment of alcohol use disorders are also discussed.
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Affiliation(s)
- Anna Warden
- The University of Texas at Austin, Waggoner Center for Alcohol & Addiction Research, Austin, TX, USA
| | - Emma Erickson
- The University of Texas at Austin, Waggoner Center for Alcohol & Addiction Research, Austin, TX, USA
| | - Gizelle Robinson
- The University of Texas at Austin, Waggoner Center for Alcohol & Addiction Research, Austin, TX, USA
| | - R Adron Harris
- The University of Texas at Austin, Waggoner Center for Alcohol & Addiction Research, Austin, TX, USA
| | - R Dayne Mayfield
- The University of Texas at Austin, Waggoner Center for Alcohol & Addiction Research, Austin, TX, USA
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Maes M, Anderson G, Kubera M, Berk M. Targeting classical IL-6 signalling or IL-6 trans-signalling in depression? Expert Opin Ther Targets 2014; 18:495-512. [PMID: 24548241 DOI: 10.1517/14728222.2014.888417] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Increased IL-6 and soluble IL-6 receptor (sIL-6R) levels in depressed patients was first shown over 20 years ago. The pro-inflammatory effects of IL-6 are predominantly mediated by IL-6 trans-signalling via the sIL-6R, whereas IL-6R membrane signalling has anti-inflammatory effects. AREAS COVERED We review data on IL-6 and sIL-6R in inflammation, depression, animal models of depression and the effects of different classes of antidepressants. The biological context for IL-6 trans-signalling as a pathogenic factor in depression involves its role in the acute phase response, disorders in zinc and the erythron, hypothalamic-pituitary-adrenal axis activation, induction of the tryptophan catabolite pathway, oxidative stress, bacterial translocation, transition towards sensitisation, autoimmune processes and neuroprogression and the multicausal aetiology of depression, considering that psychosocial stressors and comorbid immune-inflammatory diseases are associated with the onset of depression. EXPERT OPINION The homeostatic functions of IL-6 imply that ubiquitous IL-6 inhibitors, for example, tocilizumab, may not be the optimal treatment target in depression. A more promising target may be to increase soluble glycoprotein 130 (sgp130) inhibition of IL-6 trans-signalling, while allowing the maintenance of IL-6R membrane signalling. Future research should delineate the effects of treatments with sgp130Fc in combination with antidepressants in various animal models of chronic depression.
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Affiliation(s)
- Michael Maes
- Deakin University, Department of Psychiatry , Geelong , Australia
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Paredes SD, Barriga C, Reiter RJ, Rodríguez AB. Assessment of the Potential Role of Tryptophan as the Precursor of Serotonin and Melatonin for the Aged Sleep-wake Cycle and Immune Function: Streptopelia Risoria as a Model. Int J Tryptophan Res 2009; 2:23-36. [PMID: 22084580 PMCID: PMC3195230 DOI: 10.4137/ijtr.s1129] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In the present review we summarize the relationship between the amino acid, tryptophan, the neurotransmitter, serotonin, and the indole, melatonin, with the rhythms of sleep/wake and the immune response along with the possible connections between the alterations in these rhythms due to aging and the so-called “serotonin and melatonin deficiency state.” The decrease associated with aging of the brain and circulating levels of serotonin and melatonin seemingly contributes to the alterations of both the sleep/wake cycle and the immune response that typically accompany old age. The supplemental administration of tryptophan, e.g. the inclusion of tryptophan-enriched food in the diet, might help to remediate these age-related alterations due to its capacity of raise the serotonin and melatonin levels in the brain and blood. Herein, we also summarize a set of studies related to the potential role that tryptophan, and its derived product melatonin, may play in the restoration of the aged circadian rhythms of sleep/wake and immune response, taking the ringdove (Streptopeliarisoria) as a suitable model.
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Affiliation(s)
- Sergio D Paredes
- Department of Physiology (Neuroimmunophysiology Research Group), Faculty of Science, University of Extremadura, Badajoz, Spain
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Abstract
Psychological depression is shown to be associated with several aspects of coronary artery disease (CAD), including arrhythmias, myocardial infarction, heart failure and sudden death. The physiological mechanisms accounting for this association are unclear. Hypothalamic-pituitary-adrenal dysregulation, diminished heart rate variability, altered blood platelet function and noncompliance with medial treatments have been proposed as mechanisms underlying depression and cardiovascular disease. Recent evidence also suggests that reduced baroreflex sensitivity, impaired immune function, chronic fatigue and the co-morbidity of depression and anxiety may be involved in the relationship between depression and cardiovascular dysregulation. An experimental strategy using animal models for investigating underlying physiological abnormalities in depression is presented. A key to understanding the bidirectional association between depression and heart disease is to determine whether there are common changes in brain systems that are associated with these conditions. Such approaches may hold promise for advancing our understanding of the interaction between this mood disorder and CAD.
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Affiliation(s)
- Angela J Grippo
- Department of Psychology, The University of Iowa, Iowa City 52242-1407, USA
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Bonaccorso S, Lin A, Song C, Verkerk R, Kenis G, Bosmans E, Scharpe S, Vandewoude M, Dossche A, Maes M. Serotonin-immune interactions in elderly volunteers and in patients with Alzheimer's disease (DAT): lower plasma tryptophan availability to the brain in the elderly and increased serum interleukin-6 in DAT. AGING (MILAN, ITALY) 1998; 10:316-23. [PMID: 9825023 DOI: 10.1007/bf03339794] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The aims of this study were to examine the plasma availability of tryptophan, the precursor of 5-hydroxytryptamine (5-HT), and serum cytokines, such as interleukin-6 (IL-6) and IL-8, in normal elderly volunteers and in patients with Alzheimer's disease (DAT). Elderly normal volunteers (mean age = 78.3 +/- 5.7 years) had a significantly lower tryptophan/competing amino acids (valine + leucine + isoleucine + phenylalanine + tyrosine) ratio than younger subjects (mean age = 32.9 +/- 8.1 years). In normal volunteers, there were significant and inverse relationships between age and either plasma tryptophan or the tryptophan/competing amino acids ratio, and between the availability of tryptophan to the brain and serum IL-6 or IL-8. DAT patients had significantly higher serum IL-6, but not IL-8, than age-matched normal volunteers. There were no significant differences in the availability of tryptophan to the brain between DAT patients and age-matched normal volunteers. The results suggest that: 1) in normal humans, the availability of plasma tryptophan to the brain decreases with age, and with activation of the immune system; and 2) increased production of IL-6 may play a role in the pathogenesis of DAT.
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Affiliation(s)
- S Bonaccorso
- Clinical Research Center for Mental Health, Antwerp, Belgium
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