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Kandanearatchi A, Brew BJ. The kynurenine pathway and quinolinic acid: pivotal roles in HIV associated neurocognitive disorders. FEBS J 2012; 279:1366-74. [PMID: 22260426 DOI: 10.1111/j.1742-4658.2012.08500.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This brief review will first consider HIV associated neurocognitive disorder followed by the current understanding of its neuropathogenesis. Against this background the role of the kynurenine pathway will be detailed. Evidence both direct and indirect will be discussed for involvement of the kynurenine pathway at each step in the neuropathogenesis of HIV associated neurocognitive disorder.
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Cysique LA, Bain MP, Brew BJ, Murray JM. The burden of HIV-associated neurocognitive impairment in Australia and its estimates for the future. Sex Health 2012; 8:541-50. [PMID: 22127041 DOI: 10.1071/sh11003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 06/05/2011] [Indexed: 11/23/2022]
Abstract
BACKGROUND The growing number of older individuals with HIV in Australia implies that the prevalence of dementia and additional HIV-associated neurocognitive disorders will increase. There are currently no estimates of the future burden of neurocognitive disease in this population. METHODS We estimated the number and age profile of people living with HIV to the end of 2009 using HIV/AIDS Registry data, and extrapolated these estimates to 2030. Prevalence of HIV-associated dementia (HAD) from 2005 to 2010 from a large Sydney hospital and cost estimates from the AIDS Dementia and HIV Psychiatry Service were used to estimate future HAD burden and costs. RESULTS Based on our calculations, the number of HIV-positive individuals in Australia will increase from 16228 men and 1797 women in 2009 to 26963 men and 5224 women in 2030, while the number of individuals aged 60+ years will increase from 1140 men and 78 women to 5442 men and 721 women, i.e. a 377% increase of older men and an 825% increase in older women. Based on a 7.8% (157/2004) HAD prevalence obtained from hospital data, individuals with HAD will increase in number from 1314 men and 143 women in 2009 to 2204 men and 421 women in 2030. An estimated 22 men and 2 women with non-HIV dementia in 2009 will increase to 104 men and 12 women by 2030. The annual cost of care will increase from ~$29 million in 2009 to $53 million in 2030, mostly for full-time residential care. CONCLUSIONS Neurocognitive disorders will place an increasing burden on resources, especially as those living with HIV age. Because it is unclear if HAD is an increased risk factor for non-HIV dementia, our calculations may be conservative.
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Cysique LA, Maruff P, Bain MP, Wright E, Brew BJ. HIV and age do not substantially interact in HIV-associated neurocognitive impairment. J Neuropsychiatry Clin Neurosci 2011; 23:83-9. [PMID: 21304143 DOI: 10.1176/jnp.23.1.jnp83] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The authors investigated the combined age and HIV effects on cognitive functions in 146 individuals, 116 of whom had HIV infection. Forty-two percent had HIV-associated neurocognitive disorder, and all were receiving highly active antiretroviral therapy. Using linear and nonlinear regression modeling, the authors found only a trending effect of the quadratic term HIV status × age, both including dementia cases (p=0.12) and excluding dementia cases (p<0.06). Our results suggest that either this early-2000 cohort is not old enough to detect a clear interactive age and HIV effect or that there may be a survivor bias for individuals with long-term infection. Further longitudinal studies are warranted.
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Cysique LA, Waters EK, Brew BJ. Central nervous system antiretroviral efficacy in HIV infection: a qualitative and quantitative review and implications for future research. BMC Neurol 2011; 11:148. [PMID: 22107790 PMCID: PMC3252248 DOI: 10.1186/1471-2377-11-148] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 11/22/2011] [Indexed: 01/18/2023] Open
Abstract
Background There is conflicting information as to whether antiretroviral drugs with better central nervous system (CNS) penetration (neuroHAART) assist in improving neurocognitive function and suppressing cerebrospinal fluid (CSF) HIV RNA. The current review aims to better synthesise existing literature by using an innovative two-phase review approach (qualitative and quantitative) to overcome methodological differences between studies. Methods Sixteen studies, all observational, were identified using a standard citation search. They fulfilled the following inclusion criteria: conducted in the HAART era; sample size > 10; treatment effect involved more than one antiretroviral and none had a retrospective design. The qualitative phase of review of these studies consisted of (i) a blind assessment rating studies on features such as sample size, statistical methods and definitions of neuroHAART, and (ii) a non-blind assessment of the sensitivity of the neuropsychological methods to HIV-associated neurocognitive disorder (HAND). During quantitative evaluation we assessed the statistical power of studies, which achieved a high rating in the qualitative analysis. The objective of the power analysis was to determine the studies ability to assess their proposed research aims. Results After studies with at least three limitations were excluded in the qualitative phase, six studies remained. All six found a positive effect of neuroHAART on neurocognitive function or CSF HIV suppression. Of these six studies, only two had statistical power of at least 80%. Conclusions Studies assessed as using more rigorous methods found that neuroHAART was effective in improving neurocognitive function and decreasing CSF viral load, but only two of those studies were adequately statistically powered. Because all of these studies were observational, they represent a less compelling evidence base than randomised control trials for assessing treatment effect. Therefore, large randomised trials are needed to determine the robustness of any neuroHAART effect. However, such trials must be longitudinal, include the full spectrum of HAND, ideally carefully control for co-morbidities, and be based on optimal neuropsychology methods.
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Hillman RJ, Pett S, Marriott D, Carr A, Cooper DA, Matthews GV, Brew BJ, Milliken S, Botes LP. Participants' perspectives of high resolution anoscopy. Sex Health 2011; 8:255-6. [PMID: 21592443 DOI: 10.1071/sh10116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 11/15/2010] [Indexed: 01/08/2023]
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Botes LP, Jin F, Bourne C, Pett S, Marriott D, Carr A, Cooper DA, Matthews G, Brew BJ, Hillman RJ. Participants' perspectives of self-collected anal cytological swabs. Sex Health 2011; 8:257-8. [PMID: 21592444 DOI: 10.1071/sh10037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 09/07/2010] [Indexed: 11/23/2022]
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McManus H, Li PCK, Nolan D, Bloch M, Kiertiburanakul S, Choi JY, Mulhall B, Petoumenos K, Zhou J, Law M, Brew BJ, Wright E. Does use of antiretroviral therapy regimens with high central nervous system penetration improve survival in HIV-infected adults? HIV Med 2011; 12:610-9. [PMID: 21819527 DOI: 10.1111/j.1468-1293.2011.00938.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The aim of the study was to determine whether combination antiretroviral therapy (cART) with high central nervous system penetration-effectiveness (CPE) rank (neurocART) is associated with increased survival benefit compared with non-neurocART. METHODS Prospective data were examined for HIV-positive patients in the Asia Pacific HIV Observational Database who had commenced cART. CPE rank was calculated using the 2010 rankings process. NeurocART status was assigned to regimens with a CPE rank of 8 or more. Survival was analysed using Cox proportional hazards models with covariates updated at changes in cART regimen and with deaths up to 90 days after regimen cessation attributed to that regimen. Sensitivity analyses were conducted to examine the robustness of analysis assumptions. RESULTS Among 5882 patients, 308 deaths occurred. The hazard ratio (HR) for neurocART use was 0.89 (P=0.35) when data were stratified by cohort and adjusted for age, mode of HIV exposure, hepatitis B virus coinfection, AIDS-defining illness, CD4 count (cells/μL) and regimen count. Sensitivity analyses showed similar nonsignificant results. We also examined a composite endpoint of AIDS-defining illness or death (HR=0.93; P=0.61), baseline regimen as neurocART (HR=0.95; P=0.69), CPE category (P=0.71) and prior neurocART duration (P=0.16). No association between CD4 cell count and neurocART use was observed (P=0.52). CONCLUSIONS Our findings do not show a significant overall survival benefit associated with neurocART compared with cART. The potential benefit associated with neurocART in terms of prevention of neurocognitive impairment did not translate into an improvement in overall survival in this population. These findings were limited by the low incidence of associated mortality. Further studies and more extensive data are needed to address these limitations.
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Tippett E, Cheng WJ, Westhorpe C, Cameron PU, Brew BJ, Lewin SR, Jaworowski A, Crowe SM. Differential expression of CD163 on monocyte subsets in healthy and HIV-1 infected individuals. PLoS One 2011; 6:e19968. [PMID: 21625498 PMCID: PMC3098854 DOI: 10.1371/journal.pone.0019968] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 04/19/2011] [Indexed: 12/16/2022] Open
Abstract
CD163, a haptoglobin-hemoglobin (Hp-Hb) scavenger receptor, expressed by monocytes and macrophages, is important in resolution of inflammation. Age-related non-AIDS co-morbidities in HIV-infected individuals, particularly dementia and cardiovascular disease, result in part from effects of HIV-1 infection on monocyte and macrophage biology. CD163 co-expression on CD14+CD16++ monocytes has been proposed as a useful biomarker for HIV-1 disease progression and the presence of HIV associated dementia. Here we investigated CD163 expression on monocyte subsets ex vivo, on cultured macrophages, and soluble in plasma, in the setting of HIV-1 infection. Whole blood immunophenotyping revealed CD163 expression on CD14++CD16- monocytes but not on CD14+CD16++ monocytes (P = 0.004), supported by CD163 mRNA levels. Incubation with M-CSF induced CD163 protein expression on CD14+CD16++ monocytes to the same extent as CD14++CD16− monocytes. CD163 expression on CD14++CD16+ monocytes from HIV-infected subjects was significantly higher than from uninfected individuals, with a trend towards increased expression on CD14++CD16− monocytes (P = 0.019 and 0.069 respectively), which is accounted for by HIV-1 therapy including protease inhibitors. Shedding of CD163 was shown to predominantly occur from the CD14++CD16− subset after Ficoll isolation and LPS stimulation. Soluble CD163 concentration in plasma from HIV-1 infected donors was similar to HIV-1 uninfected donors. Monocyte CD163 expression in HIV-1 infected patients showed a complicated relationship with classical measures of disease progression. Our findings clarify technical issues regarding CD163 expression on monocyte subsets and further elucidates its role in HIV-associated inflammation by demonstrating that CD163 is readily lost from CD14++CD16− monocytes and induced in pro-inflammatory CD14+CD16++ monocytes by M-CSF. Our data show that all monocyte subsets are potentially capable of differentiating into CD163-expressing anti-inflammatory macrophages given appropriate stimuli. Levels of CD163 expression on monocytes may be a potential biomarker reflecting efforts by the immune system to resolve immune activation and inflammation in HIV-infected individuals.
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Maher AD, Cysique LA, Brew BJ, Rae CD. Statistical integration of 1H NMR and MRS data from different biofluids and tissues enhances recovery of biological information from individuals with HIV-1 infection. J Proteome Res 2011; 10:1737-45. [PMID: 21244037 DOI: 10.1021/pr1010263] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is widely used in metabonomics studies, but optimal recovery of latent biological information requires increasingly sophisticated statistical methods to identify quantitative relationships within these often highly complex data sets. Statistical heterospectroscopy (SHY) extracts latent relationships between NMR and mass spectrometry (MS) data from the same samples. Here we extend this concept to identify novel metabolic correlations between different biofluids and tissues from the same individuals. We acquired NMR data from blood plasma and cerebrospinal fluid (CSF) (N = 19) from HIV-1-infected individuals, who are known to be susceptible to neuropsychological dysfunction. We compared two computational approaches to SHY, namely the Pearson's product moment correlation and the Spearman's rank correlation. High correlations were observed for glutamine, valine, and polyethylene glycol, a drug delivery vehicle. Orthogonal projections to latent structures (OPLS) identified metabolites in blood plasma spectra that predicted the amounts of key CSF metabolites such as lactate, glutamine, and myo-inositol. Finally, brain metabolic data from magnetic resonance spectroscopy (MRS) measurements in vivo were integrated with CSF data to identify an association between 3-hydroxyvalerate and frontal white matter N-acetyl aspartate levels. The results underscore the utility of tools such as SHY and OPLS for coanalysis of high dimensional data sets to recover biological information unobtainable when such data are analyzed in isolation.
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Croitoru-Lamoury J, Lamoury FMJ, Caristo M, Suzuki K, Walker D, Takikawa O, Taylor R, Brew BJ. Interferon-γ regulates the proliferation and differentiation of mesenchymal stem cells via activation of indoleamine 2,3 dioxygenase (IDO). PLoS One 2011; 6:e14698. [PMID: 21359206 PMCID: PMC3040184 DOI: 10.1371/journal.pone.0014698] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 01/13/2011] [Indexed: 12/15/2022] Open
Abstract
The kynurenine pathway (KP) of tryptophan metabolism is linked to antimicrobial activity and modulation of immune responses but its role in stem cell biology is unknown. We show that human and mouse mesenchymal and neural stem cells (MSCs and NSCs) express the complete KP, including indoleamine 2,3 dioxygenase 1 (IDO) and IDO2, that it is highly regulated by type I (IFN-β) and II interferons (IFN-γ), and that its transcriptional modulation depends on the type of interferon, cell type and species. IFN-γ inhibited proliferation and altered human and mouse MSC neural, adipocytic and osteocytic differentiation via the activation of IDO. A functional KP present in MSCs, NSCs and perhaps other stem cell types offers novel therapeutic opportunities for optimisation of stem cell proliferation and differentiation.
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Chen Y, Brew BJ, Guillemin GJ. Characterization of the kynurenine pathway in NSC-34 cell line: implications for amyotrophic lateral sclerosis. J Neurochem 2011; 118:816-25. [PMID: 21182524 DOI: 10.1111/j.1471-4159.2010.07159.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common type of motor neuron degenerative disease for which the aetiology is still unknown. The kynurenine pathway (KP) is a major degradative pathway of tryptophan ultimately leading to the production of NAD(+) and is also one of the major regulatory mechanisms of the immune response. The KP is known to be involved in several neuroinflammatory disorders. Among the KP intermediates, quinolinic acid (QUIN) is a potent excitotoxin, while kynurenic acid and picolinic acid are both neuroprotectant. This study aimed to (i) characterize the components of the KP in NSC-34 cells (a rodent motor neuron cell line) and (ii) assess the effects of QUIN on the same cells. RT-PCR and immunocytochemistry were used to characterize the KP enzymes, and lactate dehydrogenase (LDH) test was used to assess the effect of QUIN in the absence and presence of NMDA receptor antagonists, kynurenines and 1-methyl tryptophan. Our data demonstrate that a functional KP is present in NSC-34 cells. LDH tests showed that (i) QUIN toxicity on NSC-34 cells increases with time and concentration; (ii) NMDA antagonists, 2-amino-5-phosphonopentanoic acid, MK-801 and memantine, can partially decrease QUIN toxicity; (iii) kynurenic acid can decrease LDH release in a linear manner, whereas picolinic acid does the same but non-linearly; and (iv) 1-methyl tryptophan is effective in decreasing QUIN release by the rodent microglial cell line BV-2 and thus protects NSC-34 from cell death. There is currently a lack of effective treatment for ALS and our in vitro results provide a novel therapeutic strategy for ALS patients.
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Lee MC, Ting KK, Adams S, Brew BJ, Chung R, Guillemin GJ. Characterisation of the expression of NMDA receptors in human astrocytes. PLoS One 2010; 5:e14123. [PMID: 21152063 PMCID: PMC2994931 DOI: 10.1371/journal.pone.0014123] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 10/26/2010] [Indexed: 12/14/2022] Open
Abstract
Astrocytes have long been perceived only as structural and supporting cells within the central nervous system (CNS). However, the discovery that these glial cells may potentially express receptors capable of responding to endogenous neurotransmitters has resulted in the need to reassess astrocytic physiology. The aim of the current study was to characterise the expression of NMDA receptors (NMDARs) in primary human astrocytes, and investigate their response to physiological and excitotoxic concentrations of the known endogenous NMDAR agonists, glutamate and quinolinic acid (QUIN). Primary cultures of human astrocytes were used to examine expression of these receptors at the mRNA level using RT-PCR and qPCR, and at the protein level using immunocytochemistry. The functionality role of the receptors was assessed using intracellular calcium influx experiments and measuring extracellular lactate dehydrogenase (LDH) activity in primary cultures of human astrocytes treated with glutamate and QUIN. We found that all seven currently known NMDAR subunits (NR1, NR2A, NR2B, NR2C, NR2D, NR3A and NR3B) are expressed in astrocytes, but at different levels. Calcium influx studies revealed that both glutamate and QUIN could activate astrocytic NMDARs, which stimulates Ca2+ influx into the cell and can result in dysfunction and death of astrocytes. Our data also show that the NMDAR ion channel blockers, MK801, and memantine can attenuate glutamate and QUIN mediated cell excitotoxicity. This suggests that the mechanism of glutamate and QUIN gliotoxicity is at least partially mediated by excessive stimulation of NMDARs. The present study is the first to provide definitive evidence for the existence of functional NMDAR expression in human primary astrocytes. This discovery has significant implications for redefining the cellular interaction between glia and neurons in both physiological processes and pathological conditions.
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Dore GJ, Law MG, Brew BJ. Prospective Analysis of Seizures Occurring in Human Immunodeficiency Virus Type-1 Infection. ACTA ACUST UNITED AC 2010; 1:59-69. [PMID: 16873179 DOI: 10.1300/j128v01n04_06] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A prospective, case-control study was undertaken to characterise seizures occurring in the context of human immunodeficiency type-1 (HIV-1) infection. Fifty consecutive patients with a documented seizure were enrolled along with fifty control patients. Among cases the median CD4 cell count was 8/mm3 and 84% had a prior AIDS defining illness; 14/mm3 and 80% among the control group. Generalised seizures were seen in 84%, partial with secondary generalisation in 10% and partial in 6%. Associated conditions included cerebral toxoplasmosis (22%), cryptococcal meningitis (8%), progressive multifocal leukoencephalopathy (6%), cytomegalovirus encephalitis (6%), central nervous system (CNS) lymphoma (2%), and other causes (14%) including pre-HIV epilepsy. No associated condition was identified in 42% of patients of whom 18% were receiving foscarnet therapy at the time of seizure, compared with 4% of control patients (p < 0.001). Concentrations of cerebrospinal fluid â2-microglobulin and neopterin, markers that have been associated with HIV-1 involvement of the CNS, were elevated in 12/12 and 13/13 patients, respectively, of the group with no identifiable cause for their seizure. We conclude that seizures occur principally in patients with advanced HIV-1 disease, with opportunistic infections of the CNS the predominant underlying condition. In the group with no identifiable cause foscarnet therapy and subclinical HIV-1 involvement of the CNS may be factors responsible for seizure activity.
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Wright EJ, Nunn M, Joseph J, Robertson K, Lal L, Brew BJ. NeuroAIDS in the Asia Pacific Region. J Neurovirol 2010; 14:465-73. [PMID: 19031289 DOI: 10.1080/13550280802235932] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Over 8.3 million people living in the Asia Pacific region are human immunodeficiency virus (HIV) positive and up to 40% of these individuals have had prior acquired immunodeficiency syndrome (AIDS) illnesses. Recently endeavors have been made to better characterize the burden of HIV-related neurological disease within the Asia Pacific region and, with this in mind, the NeuroAIDS in Asia and the Pacific Rim workshop was held in Sydney, Australia, as an affiliated event of the 4th IAS Conference on HIV Pathogenesis, Treatment and Prevention. The workshop was supported by the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute of Mental Health (NIMH) of the United States National Institutes of Health and the Australian Government overseas AID program, AusAID. HIV neurologists, infectious disease physicians, pediatricians, psychiatrists, immunologists, virologists,and researchers from 12 countries of the Asia Pacific region (including Australia), the United States, and the United Kingdom attended the meeting. A broad range of topics were addressed, including common HIV neurological disorders, the lack of diagnostic, management, and research infrastructure, central nervous system (CNS) immune restoration disease, pediatric neuroAIDS, and current clinical and laboratory research projects being undertaken within the Asia Pacific region.
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Tisch S, Brew BJ. HIV, HAART, and Parkinson's disease: Co-incidence or pathogenetic link? Mov Disord 2010; 25:2257-8; author reply 2257. [DOI: 10.1002/mds.23277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Lim CK, Brew BJ, Sundaram G, Guillemin GJ. Understanding the roles of the kynurenine pathway in multiple sclerosis progression. Int J Tryptophan Res 2010; 3:157-67. [PMID: 22084596 PMCID: PMC3195238 DOI: 10.4137/ijtr.s4294] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The kynurenine pathway (KP) is a major degradative pathway of tryptophan ultimately leading to the production of nicotinamide adenine dinucleotide (NAD+) and is also one of the major regulatory mechanisms of the immune response. The KP is known to be involved in several neuroinflammatory disorders including Alzheimer’s disease, amyotrophic lateral sclerosis, AIDS dementia complex, Parkinson’s disease, schizophrenia, Huntington’s disease and brain tumours. However, the KP remains a relatively new topic for the field of multiple sclerosis (MS). Over the last 2–3 years, some evidence has progressively emerged suggesting that the KP is likely to be involved in the pathogenesis of autoimmune diseases especially MS. Some KP modulators are already in clinical trials for other inflammatory diseases and would potentially provide a new and important therapeutic strategy for MS patients. This review summarizes the known relationships between the KP and MS.
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Wright EJ, Grund B, Robertson K, Brew BJ, Roediger M, Bain MP, Drummond F, Vjecha MJ, Hoy J, Miller C, Penalva de Oliveira AC, Pumpradit W, Shlay JC, El-Sadr W, Price RW. Cardiovascular risk factors associated with lower baseline cognitive performance in HIV-positive persons. Neurology 2010; 75:864-73. [PMID: 20702792 DOI: 10.1212/wnl.0b013e3181f11bd8] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
OBJECTIVE To determine factors associated with baseline neurocognitive performance in HIV-infected participants enrolled in the Strategies for Management of Antiretroviral Therapy (SMART) neurology substudy. METHODS Participants from Australia, North America, Brazil, and Thailand were administered a 5-test neurocognitive battery. Z scores and the neurocognitive performance outcome measure, the quantitative neurocognitive performance z score (QNPZ-5), were calculated using US norms. Neurocognitive impairment was defined as z scores <-2 in two or more cognitive domains. Associations of test scores, the QNPZ-5, and impairment with baseline factors including demographics and risk factors for HIV-associated dementia (HAD) and cardiovascular disease (CVD) were determined in multiple regression. RESULTS The 292 participants had a median CD4 cell count of 536 cells/mm(3), 88% had an HIV viral load < or =400 copies/mL, and 92% were taking antiretrovirals. Demographics, HIV, and clinical factors differed between locations. The mean QNPZ-5 score was -0.72; 14% of participants had neurocognitive impairment. For most tests, scores and z scores differed significantly between locations, with and without adjustment for age, sex, education, and race. Prior CVD was associated with neurocognitive impairment. Prior CVD, hypercholesterolemia, and hypertension were associated with poorer neurocognitive performance but conventional HAD risk factors and the CNS penetration effectiveness rank of antiretroviral regimens were not. CONCLUSIONS In this HIV-positive population with high CD4 cell counts, neurocognitive impairment was associated with prior CVD. Lower neurocognitive performance was associated with prior CVD, hypertension, and hypercholesterolemia, but not conventional HAD risk factors. The contribution of CVD and cardiovascular risk factors to the neurocognition of HIV-positive populations warrants further investigation.
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Guillemin GJ, Rahman A, Ting KK, Cullen K, Braidy N, Chung R, Wu W, Brew BJ. P4‐002: Involvement of the Kynurenine Pathway in Alzheimer's Disease. Alzheimers Dement 2010. [DOI: 10.1016/j.jalz.2010.08.063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Cherry CL, Affandi JS, Brew BJ, Creighton J, Djauzi S, Hooker DJ, Imran D, Kamarulzaman A, Kamerman P, McArthur JC, Moore RD, Price P, Smyth K, Tan IL, Vanar S, Wadley A, Wesselingh SL, Yunihastuti E. Hepatitis C seropositivity is not a risk factor for sensory neuropathy among patients with HIV. Neurology 2010; 74:1538-42. [PMID: 20458071 DOI: 10.1212/wnl.0b013e3181dd436d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Sensory neuropathy (SN) is common in patients with HIV. Hepatitis C (HCV) coinfection is often cited as an HIV-SN risk factor, but data to support this are lacking. This collaboration aimed to examine the association between HCV serostatus and SN risk among ambulatory HIV-positive patients. METHODS Patients with HIV were assessed in cross-sectional studies in Baltimore, Jakarta, Johannesburg, Kuala Lumpur, Melbourne, and Sydney for SN (defined by both supportive symptoms and signs). HCV seropositivity was assessed as an SN risk using a chi(2) test, followed by logistic regression modeling to correct for treatment exposures and demographics. RESULTS A total of 837 patients of African, Asian, and Caucasian descent were studied. HCV seroprevalence varied by site (Baltimore n = 104, 61% HCV+; Jakarta 96, 51%; Johannesburg 300, 1%; Kuala Lumpur 97, 10%; Melbourne 206, 16%; Sydney 34, 18%). HCV seropositivity was not associated with increased SN risk at any site, but was associated with reduced SN risk in Melbourne (p = 0.003). On multivariate analyses, the independent associations with SN were increasing age, height, and stavudine exposure. HCV seropositivity was not independently associated with an increased SN risk at any site, but associated independently with reduced SN risk in Baltimore (p = 0.04) and Melbourne (p = 0.06). CONCLUSIONS Hepatitis C (HCV) seropositivity was not associated with increased sensory neuropathy risk among HIV-positive patients at any site. While we were unable to assess HCV RNA or liver damage, the data suggest that HCV coinfection is not a major contributor to HIV-SN. HCV = hepatitis C; SN = sensory neuropathy.
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Zhou L, Diefenbach E, Crossett B, Tran SL, Ng T, Rizos H, Rua R, Wang B, Kapur A, Gandhi K, Brew BJ, Saksena NK. First evidence of overlaps between HIV-Associated Dementia (HAD) and non-viral neurodegenerative diseases: proteomic analysis of the frontal cortex from HIV+ patients with and without dementia. Mol Neurodegener 2010; 5:27. [PMID: 20573273 PMCID: PMC2904315 DOI: 10.1186/1750-1326-5-27] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2009] [Accepted: 06/24/2010] [Indexed: 12/12/2022] Open
Abstract
Background The pathogenesis of HIV-associated dementia (HAD) is poorly understood. To date, detailed proteomic fingerprinting directly from autopsied brain tissues of HAD and HIV non-dementia patients has not been performed. Result Here, we have analyzed total proteins from the frontal cortex of 9 HAD and 5 HIV non-dementia patients. Using 2-Dimensional differential in-gel electrophoresis (2-DIGE) to analyze the brain tissue proteome, 76 differentially expressed proteins (p < 0.05; fold change>1.25) were identified between HAD and HIV non-dementia patients, of which 36 protein spots (based on 3D appearance of spots on the images) were chosen for the mass spectrometry analysis. The large majority of identified proteins were represented in the energy metabolic (mitochondria) and signal transduction pathways. Furthermore, over 90% of the protein candidates are common to both HAD and other non-viral neurodegenerative disease, such as Alzheimer's disease. The data was further validated using specific antibodies to 4 proteins (CA2, GS, CKMT and CRMP2) by western blot (WB) in the same samples used for 2D-DIGE, with additional confirmation by immunohistochemitsry (IHC) using frontal lobe tissue from different HAD and HIV+ non-dementia patients. The validation for all 4 antibodies by WB and IHC was in concordance with the DIGE results, lending further credence to the current findings. Conclusion These results suggest not only convergent pathogenetic pathways for the two diseases but also the possibility of increased Alzheimer's disease (AD) susceptibility in HAD patients whose life expectancy has been significantly increased by highly active antiretroviral therapy.
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Davies NW, Guillemin G, Brew BJ. Tryptophan, Neurodegeneration and HIV-Associated Neurocognitive Disorder. Int J Tryptophan Res 2010; 3:121-40. [PMID: 22084594 PMCID: PMC3195234 DOI: 10.4137/ijtr.s4321] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
This review presents an up-to-date assessment of the role of the tryptophan metabolic and catabolic pathways in neurodegenerative disease and HIV-associated neurocognitive disorder. The kynurenine pathway and the effects of each of its enzymes and products are reviewed. The differential expression of the kynurenine pathway in cells within the brain, including inflammatory cells, is explored given the increasing recognition of the importance of inflammation in neurodegenerative disease. An overview of common mechanisms of neurodegeneration is presented before a review and discussion of the evidence for a pathogenetic role of the kynurenine pathway in Alzheimer's disease, HIV-associated neurocognitive disorder, Huntington's disease, motor neurone disease, and Parkinson's disease.
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Hagberg L, Cinque P, Gisslen M, Brew BJ, Spudich S, Bestetti A, Price RW, Fuchs D. Cerebrospinal fluid neopterin: an informative biomarker of central nervous system immune activation in HIV-1 infection. AIDS Res Ther 2010; 7:15. [PMID: 20525234 PMCID: PMC2890504 DOI: 10.1186/1742-6405-7-15] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 06/03/2010] [Indexed: 11/24/2022] Open
Abstract
HIV-1 invades the central nervous system (CNS) in the context of acute infection, persists thereafter in the absence of treatment, and leads to chronic intrathecal immunoactivation that can be measured by the macrophage activation marker, neopterin, in cerebrospinal fluid (CSF). In this review we describe our experience with CSF neopterin measurements in 382 untreated HIV-infected patients across the spectrum of immunosuppression and HIV-related neurological diseases, in 73 untreated AIDS patients with opportunistic CNS infections, and in 233 treated patients. In untreated patients, CSF neopterin concentrations are almost always elevated and increase progressively as immunosuppression worsens and blood CD4 cell counts fall. However, patients with HIV dementia exhibit particularly high CSF neopterin concentrations, above those of patients without neurological disease, though patients with CNS opportunistic infections, including CMV encephalitis and cryptococcal meningitis, also exhibit high levels of CSF neopterin. Combination antiretroviral therapy, with its potent effect on CNS HIV infection and CSF HIV RNA, mitigates both intrathecal immunoactivation and lowers CSF neopterin. However, despite suppression of plasma and CSF HIV RNA to below the detection limits of clinical assays (<50 copies HIV RNA/mL), CSF neopterin often remains mildly elevated, indicating persistent low-level intrathecal immune activation and raising the important questions of whether this elevation is driven by continued CNS infection and whether it causes continued indolent CNS injury. Although nonspecific, CSF neopterin can serve as a useful biomarker in the diagnosis of HIV dementia in the setting of confounding conditions, in monitoring the CNS inflammatory effects of antiretroviral treatment, and give valuable information to the cause of ongoing brain injury.
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Brew BJ. Benefit or toxicity from neurologically targeted antiretroviral therapy? Clin Infect Dis 2010; 50:930-2. [PMID: 20146628 DOI: 10.1086/650744] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Cysique LA, Murray JM, Dunbar M, Jeyakumar V, Brew BJ. A screening algorithm for HIV-associated neurocognitive disorders. HIV Med 2010; 11:642-9. [DOI: 10.1111/j.1468-1293.2010.00834.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gisslén M, Krut J, Andreasson U, Blennow K, Cinque P, Brew BJ, Spudich S, Hagberg L, Rosengren L, Price RW, Zetterberg H. Amyloid and tau cerebrospinal fluid biomarkers in HIV infection. BMC Neurol 2009; 9:63. [PMID: 20028512 PMCID: PMC2807422 DOI: 10.1186/1471-2377-9-63] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 12/22/2009] [Indexed: 12/04/2022] Open
Abstract
Background Because of the emerging intersections of HIV infection and Alzheimer's disease, we examined cerebrospinal fluid (CSF) biomarkers related of amyloid and tau metabolism in HIV-infected patients. Methods In this cross-sectional study we measured soluble amyloid precursor proteins alpha and beta (sAPPα and sAPPβ), amyloid beta fragment 1-42 (Aβ1-42), and total and hyperphosphorylated tau (t-tau and p-tau) in CSF of 86 HIV-infected (HIV+) subjects, including 21 with AIDS dementia complex (ADC), 25 with central nervous system (CNS) opportunistic infections and 40 without neurological symptoms and signs. We also measured these CSF biomarkers in 64 uninfected (HIV-) subjects, including 21 with Alzheimer's disease, and both younger and older controls without neurological disease. Results CSF sAPPα and sAPPβ concentrations were highly correlated and reduced in patients with ADC and opportunistic infections compared to the other groups. The opportunistic infection group but not the ADC patients had lower CSF Aβ1-42 in comparison to the other HIV+ subjects. CSF t-tau levels were high in some ADC patients, but did not differ significantly from the HIV+ neuroasymptomatic group, while CSF p-tau was not increased in any of the HIV+ groups. Together, CSF amyloid and tau markers segregated the ADC patients from both HIV+ and HIV- neuroasymptomatics and from Alzheimer's disease patients, but not from those with opportunistic infections. Conclusions Parallel reductions of CSF sAPPα and sAPPβ in ADC and CNS opportunistic infections suggest an effect of CNS immune activation or inflammation on neuronal amyloid synthesis or processing. Elevation of CSF t-tau in some ADC and CNS infection patients without concomitant increase in p-tau indicates neural injury without preferential accumulation of hyperphosphorylated tau as found in Alzheimer's disease. These biomarker changes define pathogenetic pathways to brain injury in ADC that differ from those of Alzheimer's disease.
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Ting KK, Brew BJ, Guillemin GJ. Effect of quinolinic acid on human astrocytes morphology and functions: implications in Alzheimer's disease. J Neuroinflammation 2009; 6:36. [PMID: 20003262 PMCID: PMC2797503 DOI: 10.1186/1742-2094-6-36] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 12/10/2009] [Indexed: 02/06/2023] Open
Abstract
The excitotoxin quinolinic acid (QUIN) is synthesized through the kynurenine pathway (KP) by activated monocyte lineage cells. QUIN is likely to play a role in the pathogenesis of several major neuroinflammatory diseases including Alzheimer's disease (AD). The presence of reactive astrocytes, astrogliosis, increased oxidative stress and inflammatory cytokines are important pathological hallmarks of AD. We assessed the stimulatory effects of QUIN at low physiological to high excitotoxic concentrations in comparison with the cytokines commonly associated with AD including IFN-γ and TNF-α on primary human astrocytes. We found that QUIN induces IL-1β expression, a key mediator in AD pathogenesis, in human astrocytes. We also explored the effect of QUIN on astrocyte morphology and functions. At low concentrations, QUIN treatment induced concomitantly a marked increase in glial fibrillary acid protein levels and reduction in vimentin levels compared to controls; features consistent with astrogliosis. At pathophysiological concentrations QUIN induced a switch between structural protein expressions in a dose dependent manner, increasing VIM and concomitantly decreasing GFAP expression. Glutamine synthetase (GS) activity was used as a functional metabolic test for astrocytes. We found a significant dose-dependent reduction in GS activity following QUIN treatment. All together, this study showed that QUIN is an important factor for astroglial activation, dysregulation and cell death with potential relevance to AD and other neuroinflammatory diseases.
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Zhou L, Rua R, Ng T, Vongrad V, Ho YS, Geczy C, Hsu K, Brew BJ, Saksena NK. Evidence for predilection of macrophage infiltration patterns in the deeper midline and mesial temporal structures of the brain uniquely in patients with HIV-associated dementia. BMC Infect Dis 2009; 9:192. [PMID: 19951441 PMCID: PMC2792226 DOI: 10.1186/1471-2334-9-192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 12/02/2009] [Indexed: 02/06/2023] Open
Abstract
Background HIV-1 penetrates the central nervous system, which is vital for HIV-associated dementia (HAD). But the role of cellular infiltration and activation together with HIV in the development of HAD is poorly understood. Methods To study activation and infiltration patterns of macrophages, CD8+ T cells in relation to HIV in diverse CNS areas of patients with and without dementia. 46 brain regions from two rapidly progressing severely demented patients and 53 regions from 4 HIV+ non-dementia patients were analyzed. Macrophage and CD8+ T cell infiltration of the CNS in relation to HIV was assessed using immuno-histochemical analysis with anti-HIV (P24), anti-CD8 and anti-CD68, anti-S-100A8 and granzyme B antibodies (cellular activation). Statistical analysis was performed with SPSS 12.0 with Student's t test and ANOVA. Results Overall, the patterns of infiltration of macrophages and CD8+ T cells were indiscernible between patients with and without dementia, but the co-localization of macrophages and CD8+ T cells along with HIV P24 antigen in the deeper midline and mesial temporal structures of the brain segregated the two groups. This predilection of infected macrophages and CD8+ T cells to the middle part of the brain was unique to both HAD patients, along with unique nature of provirus gag gene sequences derived from macrophages in the midline and mesial temporal structures. Conclusion Strong predilection of infected macrophages and CD8+ T cells was typical of the deeper midline and mesial temporal structures uniquely in HAD patients, which has some influence on neurocognitive impairment during HIV infection.
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Chen Y, Stankovic R, Cullen KM, Meininger V, Garner B, Coggan S, Grant R, Brew BJ, Guillemin GJ. The kynurenine pathway and inflammation in amyotrophic lateral sclerosis. Neurotox Res 2009; 18:132-42. [PMID: 19921535 DOI: 10.1007/s12640-009-9129-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 09/22/2009] [Accepted: 10/27/2009] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal motor neuron disease of unknown pathogenesis. The kynurenine pathway (KP), activated during neuroinflammation, is emerging as a possible contributory factor in ALS. The KP is the major route for tryptophan (TRP) catabolism. The intermediates generated can be either neurotoxic, such as quinolinic acid (QUIN), or neuroprotective, such as picolinic acid (PIC), an important endogenous chelator. The first and inducible enzyme of the pathway is indoleamine 2,3-dioxygenase (IDO). The present study aimed to characterize the expression of the KP in cerebrospinal fluid (CSF), serum and central nervous system (CNS) tissue of ALS patients. Using high performance liquid chromatography, we analysed the levels of TRP and kynurenine (KYN), and, with gas chromatography/mass spectrometry, the levels of PIC and QUIN, in the CSF and serum of ALS patients and control subjects. Immunohistochemistry was employed to determine the expression of QUIN, IDO and human leukocyte antigen-DR (HLA-DR) in sections of brain and spinal cord from ALS patients. There were significantly increased levels of CSF and serum TRP (P < 0.0001), KYN (P < 0.0001) and QUIN (P < 0.05) and decreased levels of serum PIC (P < 0.05) in ALS samples. There was a significant increase in activated microglia expressing HLA-DR (P < 0.0001) and increased neuronal and microglial expression of IDO and QUIN in ALS motor cortex and spinal cord. We show the presence of neuroinflammation in ALS and provide the first strong evidence for the involvement of the KP in ALS. These data point to an inflammation-driven excitotoxic-chelation defective mechanism in ALS, which may be amenable to inhibitors of the KP.
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Churchill MJ, Wesselingh SL, Cowley D, Pardo CA, McArthur JC, Brew BJ, Gorry PR. Extensive astrocyte infection is prominent in human immunodeficiency virus-associated dementia. Ann Neurol 2009; 66:253-8. [PMID: 19743454 DOI: 10.1002/ana.21697] [Citation(s) in RCA: 280] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Astrocyte infection with human immunodeficiency virus (HIV) is considered rare, so astrocytes are thought to play a secondary role in HIV neuropathogenesis. By combining double immunohistochemistry, laser capture microdissection, and highly sensitive multiplexed polymerase chain reaction to detect HIV DNA in single astrocytes in vivo, we showed that astrocyte infection is extensive in subjects with HIV-associated dementia, occurring in up to 19% of GFAP+ cells. In addition, astrocyte infection frequency correlated with the severity of neuropathological changes and proximity to perivascular macrophages. Our data indicate that astrocytes can be extensively infected with HIV, and suggest an important role for HIV-infected astrocytes in HIV neuropathogenesis.
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Guillemin GJ, Rahman A, Cullen KM, Ting KK, Braidy N, Brew BJ. P3‐195: Involvement of the kynurenine pathway in Alzheimer's disease. Alzheimers Dement 2009. [DOI: 10.1016/j.jalz.2009.04.1069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cysique LA, Brew BJ. Neuropsychological functioning and antiretroviral treatment in HIV/AIDS: a review. Neuropsychol Rev 2009; 19:169-85. [PMID: 19424802 DOI: 10.1007/s11065-009-9092-3] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 04/21/2009] [Indexed: 11/30/2022]
Abstract
This article presents a review of studies that have investigated the neuropsychological effects of antiretroviral treatment (ART) for HIV-1 infection. It provides a brief overview of the era of monotherapy, dual-therapy, and an extended overview of the current era of combination antiretroviral therapy (CART). This review highlights that while CART has had a dramatic effect on the incidence and the severity of HIV-associated neurocognitive disorders (HAND), HAND, in its mild form, still remains prevalent. New causes of this sustained prevalence are poor CNS penetration of some antiretroviral agents, drug resistance, poor adherence, potential neurotoxicity, co-morbidities such as the long-term CART side effects in relation to cardio-vascular disease, and chronic HIV brain infection that may facilitate the expression of new forms of neurodegenerative processes. The review emphasizes the need to address methodological limitations of published studies and the need for large and representative cross-disciplinary longitudinal investigations across the HIV illness span.
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Braidy N, Grant R, Adams S, Brew BJ, Guillemin GJ. Mechanism for Quinolinic Acid Cytotoxicity in Human Astrocytes and Neurons. Neurotox Res 2009; 16:77-86. [DOI: 10.1007/s12640-009-9051-z] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 03/31/2009] [Accepted: 04/02/2009] [Indexed: 12/28/2022]
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Braidy N, Grant R, Brew BJ, Adams S, Jayasena T, Guillemin GJ. Effects of Kynurenine Pathway Metabolites on Intracellular NAD Synthesis and Cell Death in Human Primary Astrocytes and Neurons. Int J Tryptophan Res 2009; 2:61-9. [PMID: 22084582 PMCID: PMC3195228 DOI: 10.4137/ijtr.s2318] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The kynurenine pathway (KP) is a major route of L-tryptophan catabolism resulting in the production of the essential pyridine nucleotide nicotinamide adenine dinucleotide, (NAD+). Up-regulation of the KP during inflammation leads to the release of a number of biologically active metabolites into the brain. We hypothesised that while some of the extracellular KP metabolites may be beneficial for intracellular NAD+ synthesis and cell survival at physiological concentrations, they may contribute to neuronal and astroglial dysfunction and cell death at pathophysiological concentrations. In this study, we found that treatment of human primary neurons and astrocytes with 3-hydroxyanthranilic acid (3-HAA), 3-hydroxykynurenine (3-HK), quinolinic acid (QUIN), and picolinic acid (PIC) at concentrations below 100 nM significantly increased intracellular NAD+ levels compared to non-treated cells. However, a dose dependent decrease in intracellular NAD+ levels and increased extracellular LDH activity was observed in human astrocytes and neurons treated with 3-HAA, 3-HK, QUIN and PIC at concentrations >100 nM and kynurenine (KYN), at concentrations above 1 μM. Intracellular NAD+ levels were unchanged in the presence of the neuroprotectant, kynurenic acid (KYNA), and a dose dependent increase in intracellular NAD+ levels was observed for TRP up to 1 mM. While anthranilic acid (AA) increased intracellular NAD+ levels at concentration below 10 μM in astrocytes. NAD+ depletion and cell death was observed in AA treated neurons at concentrations above 500 nM. Therefore, the differing responses of astrocytes and neurons to an increase in KP metabolites should be considered when assessing KP toxicity during neuroinflammation.
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Brew BJ, Gisslen M, Pemberton L, Cinque P, Hagberg L, Price RW, Blennow K, Spudich S. 110. CSF t-tau, p-tau and Amyloid Beta 1-42 in HIV Infection. J Clin Neurosci 2009. [DOI: 10.1016/j.jocn.2008.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Brew BJ. Neurological sequelae of primary HIV infection. HANDBOOK OF CLINICAL NEUROLOGY 2008; 85:69-77. [PMID: 18808976 DOI: 10.1016/s0072-9752(07)85005-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Wright EJ, Brew BJ, Wesselingh SL. Pathogenesis and Diagnosis of Viral Infections of the Nervous System. Neurol Clin 2008; 26:617-33, vii. [DOI: 10.1016/j.ncl.2008.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cherry CL, Duncan AJ, Mackie KF, Wesselingh SL, Brew BJ. A report on the effect of commencing enfuvirtide on peripheral neuropathy. AIDS Res Hum Retroviruses 2008; 24:1027-30. [PMID: 18724802 DOI: 10.1089/aid.2007.0300] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Enfuvirtide is the first fusion inhibitor approved for use in HIV treatment and is a useful therapeutic option for highly treatment experienced individuals. Passive reporting has associated increased neuropathy rates with enfuvirtide use in some early studies but not others. The aim of this study was to describe any functional or clinical changes consistent with neuropathy among enfuvirtide users. A prospective cohort study of patients commencing or continuing enfuvirtide at a state HIV referral service, including clinical and sensory threshold monitoring, was conducted. A total of 14 patients were studied. All had advanced HIV disease and 13 (93%) had symptoms and/or signs consistent with neuropathy at baseline. Patients who entered the study on enfuvirtide-based therapy remained neurologically stable throughout follow-up. Eleven patients were assessed preand postenfuvirtide. No evidence was found for any clear effect of enfuvirtide on neuropathic symptoms, neuropathic signs, or sensory thresholds at a cohort level (p > 0.3 for all, Wilcoxon signed rank test). However, three (21%) patients experienced worsening of existing neuropathy symptoms (transient in two cases) and two (14%) patients' symptoms improved with enfuvirtide commencement. Breakthrough HIV viremia was associated with worsening symptoms in two patients at 5 and 18 months of enfuvirtide use. This study found no clear effect on peripheral nerves from enfuvirtide. Although limited by a small sample size, this study involved patients who would have been particularly vulnerable to a neurotoxin, with advanced HIV disease and a high rate of baseline neurological abnormalities. We observed no clear evidence of neurotoxicity from enfuvirtide in this population.
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Pemberton LA, Stone E, Price P, van Bockxmeer F, Brew BJ. The relationship between ApoE, TNFA, IL1a, IL1b and IL12b genes and HIV-1-associated dementia. HIV Med 2008; 9:677-80. [PMID: 18631256 DOI: 10.1111/j.1468-1293.2008.00614.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Host genetic factors implicated in AIDS dementia complex (ADC) were studied. METHODS DNA from ADC patients (n=56), unselected HIV-seropositive patients (n=112, 171, 185 and 204) and HIV-seronegative controls (n=204, 60, 60, 96 and 624) were typed for polymorphic loci in genes encoding tumour necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, IL-1beta, IL-12 and Apolipoprotein E (ApoE). Diagnosis of ADC was based on neurological symptoms, signs and neuroimaging findings with other causes of dementia excluded. Patients selected had ADC stage > or =1 and CD4 counts of <500 cells/microL. RESULTS Allele 2 of TNFA-308 was more common in ADC patients compared to HIV-positive or HIV-negative controls (P=0.005, 0.024). No other differences between ADC patients and control groups were significant. Meta-analyses confirmed these results. CONCLUSIONS This study suggests that TNFA-308 allele 2 or an allele in linkage disequilibrium with this locus influences ADC.
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Wright E, Brew BJ, Lal L, Ali ST, Arayawichanont A, Imran D, Kamarulzaman A, Kongsaengdao S, Kruy L, Merati TP, Samintharapanya K, Sarim C, Tau G, Thangsing C, Vin-Samnang C, Wesselingh SL. Response to Birbeck et al. Epilepsia 2008; 49:541-3. [PMID: 18302631 DOI: 10.1111/j.1528-1167.2007.01529_5.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Batmanian JJ, Lam M, Matthews C, Finckh A, Duffy M, Wright R, Brew BJ, Markus R. Tissue plasminogen activator for acute ischaemic stroke. Med J Aust 2008. [DOI: 10.5694/j.1326-5377.2008.tb01732.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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143
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Thein HH, Maruff P, Krahn MD, Kaldor JM, Koorey DJ, Brew BJ, Dore GJ. Improved cognitive function as a consequence of hepatitis C virus treatment. HIV Med 2008; 8:520-8. [PMID: 17944685 DOI: 10.1111/j.1468-1293.2007.00505.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The aim of the study was to investigate the impact of treatment-related clearance of hepatitis C virus (HCV) on cognitive function. METHODS A prospective study was conducted in 19 HCV-monoinfected and 15 HIV/HCV-coinfected individuals undergoing pegylated interferon alpha-2a and ribavirin therapy between April 2003 and August 2005. Neuropsychological, mood, and health-related quality of life (HRQOL) effects were assessed using computer-based battery, Trail Making Tests, Depression Anxiety Stress Scales and the Short Form-36 health survey. RESULTS Pretreatment cognitive function, mood status, and HRQOL were similar between the HCV patient groups. Sustained virological response (SVR) rates were similar between HCV-monoinfected (68%) and HIV/HCV-coinfected (73%) groups. SVR was associated with significant improvements in some measures of cognitive function, independent of HRQOL improvement. CONCLUSIONS Our findings provide evidence to support cognitive effects of HCV independent of mood status and HRQOL profiles.
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Owe-Young R, Webster NL, Mukhtar M, Pomerantz RJ, Smythe G, Walker D, Armati PJ, Crowe SM, Brew BJ. Kynurenine pathway metabolism in human blood-brain-barrier cells: implications for immune tolerance and neurotoxicity. J Neurochem 2008; 105:1346-57. [PMID: 18221377 DOI: 10.1111/j.1471-4159.2008.05241.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The catabolic pathway of l-tryptophan (l-trp), known as the kynurenine pathway (KP), has been implicated in the pathogenesis of a wide range of brain diseases through its ability to lead to immune tolerance and neurotoxicity. As endothelial cells (ECs) and pericytes of the blood-brain-barrier (BBB) are among the first brain-associated cells that a blood-borne pathogen would encounter, we sought to determine their expression of the KP. Using RT-PCR and HPLC/GC-MS, we show that BBB ECs and pericytes constitutively express components of the KP. BBB ECs constitutively synthesized kynurenic acid, and after immune activation, kynurenine (KYN), which is secreted basolaterally. BBB pericytes produced small amounts of picolinic acid and after immune activation, KYN. These results have significant implications for the pathogenesis of inflammatory brain diseases in general, particularly human immunodeficiency virus (HIV)-related brain disease. Kynurenine pathway activation at the BBB results in local immune tolerance and neurotoxicity: the basolateral secretion of excess KYN can be further metabolized by perivascular macrophages and microglia with synthesis of quinolinic acid. The results point to a mechanism whereby a systemic inflammatory signal can be transduced across an intact BBB to cause local neurotoxicity.
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Batmanian JJ, Lam M, Matthews C, Finckh A, Duffy M, Wright R, Brew BJ, Markus R. A protocol‐driven model for the rapid initiation of stroke thrombolysis in the emergency department. Med J Aust 2007; 187:567-70. [DOI: 10.5694/j.1326-5377.2007.tb01418.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 07/29/2007] [Indexed: 11/17/2022]
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Guillemin GJ, Brew BJ, Noonan CE, Knight TG, Smythe GA, Cullen KM. Mass spectrometric detection of quinolinic acid in microdissected Alzheimer's disease plaques. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ics.2007.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Lim CK, Smythe GA, Stocker R, Brew BJ, Guillemin GJ. Characterization of the kynurenine pathway in human oligodendrocytes. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ics.2007.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ting KK, Brew BJ, Guillemin GJ. Effect of quinolinic acid on gene expression in human astrocytes: Implications for Alzheimer's disease. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ics.2007.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Guillemin GJ, Brew BJ. Chronic HIV infection leads to an Alzheimer's disease like illness. Involvement of the kynurenine pathway. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ics.2007.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Antinori A, Arendt G, Becker JT, Brew BJ, Byrd DA, Cherner M, Clifford DB, Cinque P, Epstein LG, Goodkin K, Gisslen M, Grant I, Heaton RK, Joseph J, Marder K, Marra CM, McArthur JC, Nunn M, Price RW, Pulliam L, Robertson KR, Sacktor N, Valcour V, Wojna VE. Updated research nosology for HIV-associated neurocognitive disorders. Neurology 2007; 69:1789-99. [PMID: 17914061 PMCID: PMC4472366 DOI: 10.1212/01.wnl.0000287431.88658.8b] [Citation(s) in RCA: 1920] [Impact Index Per Article: 112.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.
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