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Arjmandi-Rad S, Vestergaard Nieland JD, Goozee KG, Vaseghi S. The effects of different acetylcholinesterase inhibitors on EEG patterns in patients with Alzheimer's disease: A systematic review. Neurol Sci 2024; 45:417-430. [PMID: 37843690 DOI: 10.1007/s10072-023-07114-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/01/2023] [Indexed: 10/17/2023]
Abstract
OBJECTIVE Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common type of dementia. The early diagnosis of AD is an important factor for the control of AD progression. Electroencephalography (EEG) can be used for early diagnosis of AD. Acetylcholinesterase inhibitors (AChEIs) are also used for the amelioration of AD symptoms. In this systematic review, we reviewed the effect of different AChEIs including donepezil, rivastigmine, tacrine, physostigmine, and galantamine on EEG patterns in patients with AD. METHODS PubMed electronic database was searched and 122 articles were found. After removal of unrelated articles, 24 articles were selected for the present study. RESULTS AChEIs can decrease beta, theta, and delta frequency bands in patients with AD. However, conflicting results were found for alpha band. Some studies have shown increased alpha frequency, while others have shown decreased alpha frequency following treatment with AChEIs. The only difference was the type of drug. CONCLUSIONS We found that studies reporting the decreased alpha frequency used donepezil and galantamine, while studies reporting the increased alpha frequency used rivastigmine and tacrine. It was suggested that future studies should focus on the effect of different AChEIs on EEG bands, especially alpha frequency in patients with AD, to compare their effects and find the reason for their different influence on EEG patterns. Also, differences between the effects of AChEIs on oligodendrocyte differentiation and myelination may be another important factor. This is the first article investigating the effect of different AChEIs on EEG patterns in patients with AD.
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Affiliation(s)
- Shirin Arjmandi-Rad
- Institute for Cognitive & Brain Sciences, Shahid Beheshti University, Tehran, Iran
| | | | - Kathryn G Goozee
- KaRa Institute of Neurological Diseases Pty Ltd, Macquarie, NSW, Australia
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Salar Vaseghi
- Cognitive Neuroscience Lab, Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran.
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2
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Park MTM, Jeon P, French L, Dempster K, Chakravarty MM, MacKinley M, Richard J, Khan AR, Théberge J, Palaniyappan L. Microstructural imaging and transcriptomics of the basal forebrain in first-episode psychosis. Transl Psychiatry 2022; 12:358. [PMID: 36050318 PMCID: PMC9436926 DOI: 10.1038/s41398-022-02136-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 08/16/2022] [Accepted: 08/23/2022] [Indexed: 11/26/2022] Open
Abstract
Cholinergic dysfunction has been implicated in the pathophysiology of psychosis and psychiatric disorders such as schizophrenia, depression, and bipolar disorder. The basal forebrain (BF) cholinergic nuclei, defined as cholinergic cell groups Ch1-3 and Ch4 (Nucleus Basalis of Meynert; NBM), provide extensive cholinergic projections to the rest of the brain. Here, we examined microstructural neuroimaging measures of the cholinergic nuclei in patients with untreated psychosis (~31 weeks of psychosis, <2 defined daily dose of antipsychotics) and used magnetic resonance spectroscopy (MRS) and transcriptomic data to support our findings. We used a cytoarchitectonic atlas of the BF to map the nuclei and obtained measures of myelin (quantitative T1, or qT1 as myelin surrogate) and microstructure (axial diffusion; AxD). In a clinical sample (n = 85; 29 healthy controls, 56 first-episode psychosis), we found significant correlations between qT1 of Ch1-3, left NBM and MRS-based dorsal anterior cingulate choline in healthy controls while this relationship was disrupted in FEP (p > 0.05). Case-control differences in qT1 and AxD were observed in the Ch1-3, with increased qT1 (reflecting reduced myelin content) and AxD (reflecting reduced axonal integrity). We found clinical correlates between left NBM qT1 with manic symptom severity, and AxD with negative symptom burden in FEP. Intracortical and subcortical myelin maps were derived and correlated with BF myelin. BF-cortical and BF-subcortical myelin correlations demonstrate known projection patterns from the BF. Using data from the Allen Human Brain Atlas, cholinergic nuclei showed significant enrichment for schizophrenia and depression-related genes. Cell-type specific enrichment indicated enrichment for cholinergic neuron markers as expected. Further relating the neuroimaging correlations to transcriptomics demonstrated links with cholinergic receptor genes and cell type markers of oligodendrocytes and cholinergic neurons, providing biological validity to the measures. These results provide genetic, neuroimaging, and clinical evidence for cholinergic dysfunction in schizophrenia.
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Affiliation(s)
- Min Tae M. Park
- grid.39381.300000 0004 1936 8884Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Peter Jeon
- grid.39381.300000 0004 1936 8884Department of Medical Biophysics, Western University, London, Canada ,grid.39381.300000 0004 1936 8884Robarts Research Institute, Western University, London, Canada ,grid.415847.b0000 0001 0556 2414Lawson Health Research Institute, London, Canada
| | - Leon French
- grid.17063.330000 0001 2157 2938Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Kara Dempster
- grid.55602.340000 0004 1936 8200Department of Psychiatry, Dalhousie University, Halifax, Canada
| | - M. Mallar Chakravarty
- grid.14709.3b0000 0004 1936 8649Departments of Psychiatry and Biological and Biomedical Engineering, McGill University, Montreal, Canada ,Cerebral Imaging Centre, Douglas Research Centre, Montreal, Canada
| | - Michael MacKinley
- grid.39381.300000 0004 1936 8884Robarts Research Institute, Western University, London, Canada
| | - Julie Richard
- grid.39381.300000 0004 1936 8884Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, Canada
| | - Ali R. Khan
- grid.39381.300000 0004 1936 8884Department of Medical Biophysics, Western University, London, Canada ,grid.39381.300000 0004 1936 8884Robarts Research Institute, Western University, London, Canada
| | - Jean Théberge
- grid.39381.300000 0004 1936 8884Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, Canada ,grid.39381.300000 0004 1936 8884Department of Medical Biophysics, Western University, London, Canada ,grid.415847.b0000 0001 0556 2414Lawson Health Research Institute, London, Canada
| | - Lena Palaniyappan
- Department of Psychiatry, Schulich School of Medicine and Dentistry, Western University, London, Canada. .,Department of Medical Biophysics, Western University, London, Canada. .,Robarts Research Institute, Western University, London, Canada. .,Lawson Health Research Institute, London, Canada. .,Douglas Mental Health University Institute, Department of Psychiatry, McGill University, Montreal, Canada.
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3
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Park M, Lee HP, Kim J, Kim DH, Moon Y, Moon WJ. Brain myelin water fraction is associated with APOE4 allele status in patients with cognitive impairment. J Neuroimaging 2021; 32:521-529. [PMID: 34964524 DOI: 10.1111/jon.12960] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Apolipoprotein E4 (APOE4) is a major genetic risk factor for Alzheimer's disease. However, the effect of APOE4 status on myelin remains unclear. This study investigated the effect of APOE4 on myelin content in cognitively impaired individuals using T2* gradient echo (GRE)-based myelin water fraction (MWF) imaging. METHODS Between August 2017 and January 2019, we evaluated 39 cognitively impaired patients (median age, 75 years; male:female = 8:31; Alzheimer's disease: mild cognitive impairment = 11:28). We obtained brain MWF values from white matter hyperintensities (WMHs) and normal-appearing white matter (NAWM). Linear regression analysis was performed to investigate the relationship between the APOE4 status and MWF and cognitive function and MWF. RESULTS Among the 39 cognitively impaired patients, nine (23.1%) were APOE4 carriers and 30 (76.9%) were noncarriers. APOE4 carriers had a lower hippocampal volume than noncarriers (p = .045), but other brain volume parameters were not differed. After age adjustment, the APOE4 status was significantly associated with reduced MWF in NAWM (β = -0.310 per allele; p = .049) but not in WMH (β = -0.258 per allele; p = .113). After age adjustment, MWF in NAWM was significantly associated with Mini-Mental State Examination score (β = 0.313, p = .031). CONCLUSIONS T2* GRE-based MWF imaging can reveal myelin loss, particularly in NAWM, in cognitively impaired patients among APOE4 carriers. In vivo MWF in NAWM might be a novel imaging marker of Alzheimer's disease, for clarifying the interactions between the white matter and cognitive dysfunction with respect to the APOE4 status.
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Affiliation(s)
- Mina Park
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.,Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hong Pyo Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Junghyeob Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Dong Hyun Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea
| | - Yeonsil Moon
- Department of Neurology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
| | - Won-Jin Moon
- Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
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Kim S, Lee DW, Schachner M, Park HC. Small compounds mimicking the adhesion molecule L1 improve recovery in a zebrafish demyelination model. Sci Rep 2021; 11:5878. [PMID: 33723325 PMCID: PMC7960995 DOI: 10.1038/s41598-021-85412-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 03/01/2021] [Indexed: 02/05/2023] Open
Abstract
Demyelination leads to a loss of neurons, which results in, among other consequences, a severe reduction in locomotor function, and underlies several diseases in humans including multiple sclerosis and polyneuropathies. Considerable clinical progress has been made in counteracting demyelination. However, there remains a need for novel methods that reduce demyelination while concomitantly achieving remyelination, thus complementing the currently available tools to ameliorate demyelinating diseases. In this study, we used an established zebrafish demyelination model to test selected compounds, following a screening in cell culture experiments and in a mouse model of spinal cord injury that was aimed at identifying beneficial functions of the neural cell adhesion molecule L1. In comparison to mammalian nervous system disease models, the zebrafish allows testing of potentially promotive compounds more easily than what is possible in mammals. We found that our selected compounds tacrine and duloxetine significantly improved remyelination in the peripheral and central nervous system of transgenic zebrafish following pharmacologically induced demyelination. Given that both molecules are known to positively affect functions other than those related to L1 and in other disease contexts, we propose that their combined beneficial function raises hope for the use of these compounds in clinical settings.
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Affiliation(s)
- Suhyun Kim
- Department of Biomedical Sciences, College of Medicine, Korea University, Ansan, 15335, Republic of Korea
| | - Dong-Won Lee
- Department of Biomedical Sciences, College of Medicine, Korea University, Ansan, 15335, Republic of Korea
| | - Melitta Schachner
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA.
- Center for Neuroscience, Shantou University Medical College, Shantou, 515041, Guangdong, China.
| | - Hae-Chul Park
- Department of Biomedical Sciences, College of Medicine, Korea University, Ansan, 15335, Republic of Korea.
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5
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Benear SL, Ngo CT, Olson IR. Dissecting the Fornix in Basic Memory Processes and Neuropsychiatric Disease: A Review. Brain Connect 2020; 10:331-354. [PMID: 32567331 DOI: 10.1089/brain.2020.0749] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: The fornix is the primary axonal tract of the hippocampus, connecting it to modulatory subcortical structures. This review reveals that fornix damage causes cognitive deficits that closely mirror those resulting from hippocampal lesions. Methods: We reviewed the literature on the fornix, spanning non-human animal lesion research, clinical case studies of human patients with fornix damage, as well as diffusion-weighted imaging (DWI) work that evaluates fornix microstructure in vivo. Results: The fornix is essential for memory formation because it serves as the conduit for theta rhythms and acetylcholine, as well as providing mnemonic representations to deep brain structures that guide motivated behavior, such as when and where to eat. In rodents and non-human primates, fornix lesions lead to deficits in conditioning, reversal learning, and navigation. In humans, damage to the fornix manifests as anterograde amnesia. DWI research reveals that the fornix plays a key role in mild cognitive impairment and Alzheimer's Disease, and can potentially predict conversion from the former to the latter. Emerging DWI findings link perturbations in this structure to schizophrenia, mood disorders, and eating disorders. Cutting-edge research has investigated how deep brain stimulation of the fornix can potentially attenuate memory loss, control epileptic seizures, and even improve mood. Conclusions: The fornix is essential to a fully functioning memory system and is implicated in nearly all neurological functions that rely on the hippocampus. Future research needs to use optimized DWI methods to study the fornix in vivo, which we discuss, given the difficult nature of fornix reconstruction. Impact Statement The fornix is a white matter tract that connects the hippocampus to several subcortical brain regions and is pivotal for episodic memory functioning. Functionally, the fornix transmits essential neurotransmitters, as well as theta rhythms, to the hippocampus. In addition, it is the conduit by which memories guide decisions. The fornix is biomedically important because lesions to this tract result in irreversible anterograde amnesia. Research using in vivo imaging methods has linked fornix pathology to cognitive aging, mild cognitive impairment, psychosis, epilepsy, and, importantly, Alzheimer's Disease.
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Affiliation(s)
- Susan L Benear
- Department of Psychology, Temple University, Philadelphia, Pennsylvania, USA
| | - Chi T Ngo
- Center for Lifespan Psychology, Max Planck Institute for Human Development, Berlin, Germany
| | - Ingrid R Olson
- Department of Psychology, Temple University, Philadelphia, Pennsylvania, USA
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6
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Hampton WH, Hanik IM, Olson IR. Substance abuse and white matter: Findings, limitations, and future of diffusion tensor imaging research. Drug Alcohol Depend 2019; 197:288-298. [PMID: 30875650 PMCID: PMC6440853 DOI: 10.1016/j.drugalcdep.2019.02.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 01/14/2019] [Accepted: 02/07/2019] [Indexed: 10/27/2022]
Abstract
Individuals who abuse substances often differ from nonusers in their brain structure. Substance abuse and addiction is often associated with atrophy and pathology of grey matter, but much less is known about the role of white matter, which constitutes over half of human brain volume. Diffusion tensor imaging (DTI), a method for non-invasively estimating white matter, is increasingly being used to study addiction and substance abuse. Here we review recent DTI studies of major substances of abuse (alcohol, opiates, cocaine, cannabis, and nicotine substance abuse) to examine the relationship, specificity, causality, and permanence of substance-related differences in white matter microstructure. Across substance, users tended to exhibit differences in the microstructure of major fiber pathways, such as the corpus callosum. The direction of these differences, however, appeared substance-dependent. The subsample of longitudinal studies reviewed suggests that substance abuse may cause changes in white matter, though it is unclear to what extent such alterations are permanent. While collectively informative, some studies reviewed were limited by methodological and technical approach. We therefore also provide methodological guidance for future research using DTI to study substance abuse.
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Affiliation(s)
- William H Hampton
- Department of Psychology, College of Liberal Arts, Temple University, United States
| | - Italia M Hanik
- Department of Psychology, College of Liberal Arts, Temple University, United States
| | - Ingrid R Olson
- Department of Psychology, College of Liberal Arts, Temple University, United States.
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7
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Sun J, Zhou H, Bai F, Zhang Z, Ren Q. Remyelination: A Potential Therapeutic Strategy for Alzheimer's Disease? J Alzheimers Dis 2018; 58:597-612. [PMID: 28453483 DOI: 10.3233/jad-170036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myelin is a lipid-rich multilamellar membrane that wraps around long segments of neuronal axons and it increases the conduction of action potentials, transports the necessary trophic support to the neuronal axons, and reduces the energy consumed by the neuronal axons. Together with axons, myelin is a prerequisite for the higher functions of the central nervous system and complex forms of network integration. Myelin impairments have been suggested to lead to neuronal dysfunction and cognitive decline. Accumulating evidence, including brain imaging and postmortem and genetic association studies, has implicated myelin impairments in Alzheimer's disease (AD). Increasing data link myelin impairments with amyloid-β (Aβ) plaques and tau hyperphosphorylation, which are both present in patients with AD. Moreover, aging and apolipoprotein E (ApoE) may be involved in the myelin impairments observed in patients with AD. Decreased neuronal activity, increased Aβ levels, and inflammation further damage myelin in patients with AD. Furthermore, treatments that promote myelination contribute to the recovery of neuronal function and improve cognition. Therefore, strategies targeting myelin impairment may provide therapeutic opportunities for patients with AD.
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8
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Fields RD, Dutta DJ, Belgrad J, Robnett M. Cholinergic signaling in myelination. Glia 2017; 65:687-698. [PMID: 28101995 DOI: 10.1002/glia.23101] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/26/2016] [Accepted: 11/03/2016] [Indexed: 11/08/2022]
Abstract
There is a long history of research on acetylcholine (ACh) function in myelinating glia, but a resurgence of interest recently as a result of the therapeutic potential of manipulating ACh signaling to promote remyelination, and the broader interest in neurotransmitter signaling in activity-dependent myelination. Myelinating glia express all the major types of muscarinic and nicotinic ACh receptors at different stages of development, and acetylcholinesterase and butyrylcholinesterase are highly expressed in white matter. This review traces the history of research on ACh signaling in Schwann cells, oligodendrocytes, and in the myelin sheath, and summarizes current knowledge on the intracellular signaling and functional consequences of ACh signaling in myelinating glia. Implications of ACh in diseases, such as Alzheimer's disease, multiple sclerosis, and white matter toxicity caused by pesticides are considered, together with an outline of major questions for future research. GLIA 2017;65:687-698.
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Affiliation(s)
- R Douglas Fields
- Nervous System Development and Plasticity Section, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, Maryland
| | - Dipankar J Dutta
- Nervous System Development and Plasticity Section, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, Maryland.,Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland
| | - Jillian Belgrad
- Nervous System Development and Plasticity Section, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, Maryland
| | - Maya Robnett
- Nervous System Development and Plasticity Section, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Bethesda, Maryland
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9
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Filley CM, Fields RD. White matter and cognition: making the connection. J Neurophysiol 2016; 116:2093-2104. [PMID: 27512019 DOI: 10.1152/jn.00221.2016] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/04/2016] [Indexed: 12/14/2022] Open
Abstract
Whereas the cerebral cortex has long been regarded by neuroscientists as the major locus of cognitive function, the white matter of the brain is increasingly recognized as equally critical for cognition. White matter comprises half of the brain, has expanded more than gray matter in evolution, and forms an indispensable component of distributed neural networks that subserve neurobehavioral operations. White matter tracts mediate the essential connectivity by which human behavior is organized, working in concert with gray matter to enable the extraordinary repertoire of human cognitive capacities. In this review, we present evidence from behavioral neurology that white matter lesions regularly disturb cognition, consider the role of white matter in the physiology of distributed neural networks, develop the hypothesis that white matter dysfunction is relevant to neurodegenerative disorders, including Alzheimer's disease and the newly described entity chronic traumatic encephalopathy, and discuss emerging concepts regarding the prevention and treatment of cognitive dysfunction associated with white matter disorders. Investigation of the role of white matter in cognition has yielded many valuable insights and promises to expand understanding of normal brain structure and function, improve the treatment of many neurobehavioral disorders, and disclose new opportunities for research on many challenging problems facing medicine and society.
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Affiliation(s)
- Christopher M Filley
- Behavioral Neurology Section, Departments of Neurology and Psychiatry, University of Colorado School of Medicine, Aurora, Colorado; .,Denver Department of Veterans Affairs Medical Center, Denver, Colorado; and
| | - R Douglas Fields
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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10
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Bernier D, Bartha R, McAllindon D, Hanstock CC, Marchand Y, Dillen KNH, Gallant M, Good KP, Tibbo PG. Illness versus substance use effects on the frontal white matter in early phase schizophrenia: A 4Tesla (1)H-MRS study. Schizophr Res 2016; 175:4-11. [PMID: 27161760 DOI: 10.1016/j.schres.2016.04.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Young adults with early phase schizophrenia often report a past or current pattern of illicit substance use and/or alcohol misuse. Still, little is known about the cumulative and separate effects of each stressor on white matter tissue, at this vulnerable period of brain development. METHODS Participants involved 24 healthy controls with a past or current history of sustained illicit drug use and/or alcohol misuse (users), 23 healthy controls without such history (normative data), and 27 users with early phase schizophrenia. (1)H-MRS data were acquired from a large frontal volume encompassing 95% of white matter, using a 4Tesla scanner (LASER sequence, TR/TE 3200/46ms). RESULTS Reduced levels of choline-containing compounds (Cho) were specific to the effect of illness (Cohen's d=0.68), with 22% of the variance in Cho levels accounted for by duration of illness. Reduced levels of myoInositol (d=1.10) and creatine plus phosphocreatine (d=1.07) were specific to the effects of illness plus substance use. Effect of substance use on its own was revealed by reductions in levels of glutamate plus glutamine (d=0.83) in control users relative to normative data. CONCLUSIONS The specific effect of illness on white matter might indicate a decreased synthesis of membrane phospholipids or alternatively, reduced membrane cellular density. In terms of limitations, this study did not include patients without a lifetime history of substance use (non-users), and the specific effect of each substance used could not be studied separately.
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Affiliation(s)
- Denise Bernier
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada
| | - Robert Bartha
- Robarts Research Institute, University of Western Ontario, Ontario, Canada
| | - David McAllindon
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada; Biomedical Translational Imaging Centre, Halifax, Nova Scotia, Canada
| | | | - Yannick Marchand
- Faculty of Computer Science, Department of Psychology and Neuroscience, Dalhousie University, Nova Scotia, Canada
| | - Kim N H Dillen
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada
| | - Michelle Gallant
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada
| | - Kimberly P Good
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada
| | - Philip G Tibbo
- Department of Psychiatry, Dalhousie University, Nova Scotia, Canada.
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Olmos-Serrano JL, Kang HJ, Tyler WA, Silbereis JC, Cheng F, Zhu Y, Pletikos M, Jankovic-Rapan L, Cramer NP, Galdzicki Z, Goodliffe J, Peters A, Sethares C, Delalle I, Golden JA, Haydar TF, Sestan N. Down Syndrome Developmental Brain Transcriptome Reveals Defective Oligodendrocyte Differentiation and Myelination. Neuron 2016; 89:1208-1222. [PMID: 26924435 DOI: 10.1016/j.neuron.2016.01.042] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 11/24/2015] [Accepted: 01/21/2016] [Indexed: 11/18/2022]
Abstract
Trisomy 21, or Down syndrome (DS), is the most common genetic cause of developmental delay and intellectual disability. To gain insight into the underlying molecular and cellular pathogenesis, we conducted a multi-region transcriptome analysis of DS and euploid control brains spanning from mid-fetal development to adulthood. We found genome-wide alterations in the expression of a large number of genes, many of which exhibited temporal and spatial specificity and were associated with distinct biological processes. In particular, we uncovered co-dysregulation of genes associated with oligodendrocyte differentiation and myelination that were validated via cross-species comparison to Ts65Dn trisomy mice. Furthermore, we show that hypomyelination present in Ts65Dn mice is in part due to cell-autonomous effects of trisomy on oligodendrocyte differentiation and results in slower neocortical action potential transmission. Together, these results identify defects in white matter development and function in DS, and they provide a transcriptional framework for further investigating DS neuropathogenesis.
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Affiliation(s)
- Jose Luis Olmos-Serrano
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Hyo Jung Kang
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Life Science, Chung-Ang University, Seoul, Korea
| | - William A Tyler
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - John C Silbereis
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
| | - Feng Cheng
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, Florida, USA
| | - Ying Zhu
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mihovil Pletikos
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
| | - Lucija Jankovic-Rapan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
| | - Nathan P Cramer
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Joseph Goodliffe
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Alan Peters
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Claire Sethares
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Ivana Delalle
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Jeffrey A Golden
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Tarik F Haydar
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Nenad Sestan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, Connecticut, USA
- Departments of Genetic and Psychiatry, Program in Cellular Neuroscience, Neurodegeneration and Repair, Section of Comparative Medicine and Child Study Center, Yale School of Medicine, New Haven, Connecticut, USA
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12
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Morales AM, Ghahremani D, Kohno M, Hellemann GS, London ED. Cigarette exposure, dependence, and craving are related to insula thickness in young adult smokers. Neuropsychopharmacology 2014; 39:1816-22. [PMID: 24584328 PMCID: PMC4059909 DOI: 10.1038/npp.2014.48] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/07/2014] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
The age period spanning late adolescence to emergent adulthood is associated with the highest prevalence of cigarette smoking in the United States, and is also a time of continued brain development. Nonetheless, although prior research has shown group differences in brain structure associated with smoking status in adults, few studies have examined how smoking and associated behavioral states relate to brain structure in this age group. Neuroimaging and lesion studies have suggested that the insula, a cortical region that integrates heterogeneous signals about internal states and contributes to executive functions, plays an important role in cigarette smoking behavior. Using high-resolution structural magnetic resonance imaging, we therefore measured cortical thickness of the insula in 18 smokers and 24 nonsmokers between the ages of 16 and 21 years. There were no group differences in insula thickness, but cigarette exposure (pack-years) was negatively associated with thickness in right insula. Cigarette dependence and the urge to smoke were negatively related to cortical thickness in the right ventral anterior insula. Although the results do not demonstrate causation, they do suggest that there are effects of cigarette exposure on brain structure in young smokers, with a relatively short smoking history. It is possible that changes in the brain due to prolonged exposure or to the progression of dependence lead to more extensive structural changes, manifested in the reported group differences between adult smokers and nonsmokers. Structural integrity of the insula may have implications for predicting long-term cigarette smoking and problems with other substance abuse in this population.
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Affiliation(s)
- Angelica M Morales
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Dara Ghahremani
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA
| | - Milky Kohno
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Gerhard S Hellemann
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA
| | - Edythe D London
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA,Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA,Semel Institute of Neuroscience and Human Behavior, University of California, Los Angeles, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA, Tel: +1 310 825 0606, Fax: +1 310 825 0812, E-mail:
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13
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Kumar R, Chavez AS, Macey PM, Woo MA, Harper RM. Brain axial and radial diffusivity changes with age and gender in healthy adults. Brain Res 2013; 1512:22-36. [PMID: 23548596 DOI: 10.1016/j.brainres.2013.03.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 03/20/2013] [Accepted: 03/22/2013] [Indexed: 01/12/2023]
Abstract
White matter integrity changes with age, with the extent of variation dependent on attributes such as sex and oligodendrocyte health. Quantification of myelin and axonal integrity in healthy people would provide normative values necessary to determine pathology-related tissue characteristics with normal-aging and gender. We assessed white matter integrity with diffusion tensor imaging-based axial and radial diffusivity procedures (3.0-Tesla magnetic resonance imaging), which measure water diffusion parallel and perpendicular to axonal bundles, indicating axonal and myelin status, respectively, using region-of-interest (ROI) analyses, in 34 healthy adults (age, 46.5 ± 6.0 years, 19 male). Sex differences in diffusion values were assessed with two-sample t-tests, and diffusion changes with age using Pearson's correlations; whole-brain effect sizes were examined with voxel-based procedures. Multiple brain areas showed increased axial and radial diffusivity values reflecting declines in axonal and myelin integrity with age, especially in mid-hippocampal and posterior thalamic areas. However, axonal and myelin integrity increased in insular and occipital cortex projections with maturity. Females showed reduced fiber and myelin integrity in substantially more structures than males, and those areas included limbic, basal ganglia, pontine, and cerebellar sites. A minority of structures, confined to cerebellar, temporal, and frontal cortices, showed reduced fiber and myelin integrity with age in males over females. Whole-brain effect sizes in diffusion values between sexes and age-related changes showed findings parallel to ROI analyses. The structural differences mandate partitioning of sex and age in adult white matter pathology assessment, and likely contribute to sex-based physiological and behavioral dysfunction in aging and in multiple pathologies.
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Affiliation(s)
- Rajesh Kumar
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA 90095-1763, USA
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14
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Bozzali M, Parker GJM, Spanò B, Serra L, Giulietti G, Perri R, Magnani G, Marra C, G Vita M, Caltagirone C, Cercignani M. Brain tissue modifications induced by cholinergic therapy in Alzheimer's disease. Hum Brain Mapp 2012; 34:3158-67. [PMID: 22711258 DOI: 10.1002/hbm.22130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 04/10/2012] [Accepted: 04/27/2012] [Indexed: 11/11/2022] Open
Abstract
A previous preliminary investigation based on a novel MRI approach to map anatomical connectivity revealed areas of increased connectivity in Alzheimer's disease (AD) but not in mild cognitive impairment patients. This prompted the hypothesis tested here, that these areas might reflect phenomena of brain plasticity driven by acetylcholinesterase inhibitors (AChEIs). Thirty-eight patients with probable AD (19 under medication with AChEIs and 19 drug-naïve) were recruited together with 11 healthy controls. All subjects had MRI scanning at 3T, including volumetric and diffusion-weighted scans. Probabilistic tractography was used to initiate streamlines from all parenchymal voxels, and anatomical connectivity maps (ACMs) were obtained by counting, among the total number of streamlines initiated, the fraction passing through each brain voxel. After normalization into standard space, ACMs were used to test for between-group comparisons, and for interactions between the exposure to AChEIs and global level of cognition. Patients with AD had reduced ACM values in the fornix, cingulum, and supramarginal gyri. The ACM value was strongly associated with the AChEI dosage-x-duration product in the anterior limb (non-motor pathway) of the internal capsule. Tractography from this region identified the anterior thalamic radiation as the main white matter (WM) tract passing through it. The reduced connectivity in WM bundles connecting the hippocampi with the rest of the brain (fornix/cingulum) suggests a possible mechanism for the spread of AD pathology. An intriguing explanation for the interaction between AChEIs and ACM is related to the mechanisms of brain plasticity, partially driven by neurotrophic properties of acetylcholine replacement.
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Affiliation(s)
- Marco Bozzali
- Neuorimaging Laboratory, Santa Lucia Foundation, Rome, Italy
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15
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Bartzokis G. Neuroglialpharmacology: myelination as a shared mechanism of action of psychotropic treatments. Neuropharmacology 2012; 62:2137-53. [PMID: 22306524 PMCID: PMC3586811 DOI: 10.1016/j.neuropharm.2012.01.015] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 12/20/2022]
Abstract
Current psychiatric diagnostic schema segregate symptom clusters into discrete entities, however, large proportions of patients suffer from comorbid conditions that fit neither diagnostic nor therapeutic schema. Similarly, psychotropic treatments ranging from lithium and antipsychotics to serotonin reuptake inhibitors (SSRIs) and acetylcholinesterase inhibitors have been shown to be efficacious in a wide spectrum of psychiatric disorders ranging from autism, schizophrenia (SZ), depression, and bipolar disorder (BD) to Alzheimer's disease (AD). This apparent lack of specificity suggests that psychiatric symptoms as well as treatments may share aspects of pathophysiology and mechanisms of action that defy current symptom-based diagnostic and neuron-based therapeutic schema. A myelin-centered model of human brain function can help integrate these incongruities and provide novel insights into disease etiologies and treatment mechanisms. Available data are integrated herein to suggest that widely used psychotropic treatments ranging from antipsychotics and antidepressants to lithium and electroconvulsive therapy share complex signaling pathways such as Akt and glycogen synthase kinase-3 (GSK3) that affect myelination, its plasticity, and repair. These signaling pathways respond to neurotransmitters, neurotrophins, hormones, and nutrition, underlie intricate neuroglial communications, and may substantially contribute to the mechanisms of action and wide spectra of efficacy of current therapeutics by promoting myelination. Imaging and genetic technologies make it possible to safely and non-invasively test these hypotheses directly in humans and can help guide clinical trial efforts designed to correct myelination abnormalities. Such efforts may provide insights into novel avenues for treatment and prevention of some of the most prevalent and devastating human diseases.
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Affiliation(s)
- George Bartzokis
- Department of Psychiatry, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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16
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Hudkins M, O'Neill J, Tobias MC, Bartzokis G, London ED. Cigarette smoking and white matter microstructure. Psychopharmacology (Berl) 2012; 221:285-95. [PMID: 22215225 PMCID: PMC4111107 DOI: 10.1007/s00213-011-2621-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 11/01/2011] [Indexed: 12/28/2022]
Abstract
RATIONALE Diffusion tensor imaging has been used before in testing associations between cigarette smoking and white matter integrity, with inconsistent results. Published reports indicate higher fractional anisotropy (FA, a measure of linear water diffusion) in some brain regions and lower FA in others in adult smokers compared to nonsmokers. Adolescent smokers exhibited elevated FA at several brain regions and a positive correlation of FA in the genu corpus callosum with exposure to smoking (pack-years). OBJECTIVE To help resolve prior discrepancies, we studied adults, sampling multiple brain regions, and testing for relationships to clinical features of nicotine dependence and exposure to smoking. METHODS Brain MRI scans (1.5 T) were acquired, and FA and apparent diffusion coefficient (ADC, a measure of random diffusion) were assayed in corpus callosum and prefrontal white matter, corona radiata, internal capsule, cingulum bundle, and hippocampal perforant fibers in 18 smokers (33.7 ± 7.9 years of age) and 18 age- and gender-matched nonsmokers. RESULTS ADC showed no group difference, but smokers had higher (4.3-21.1%) FA than nonsmokers. The differences were significant in right prefrontal white matter, cingulum, and genu corpus callosum. FA in several regions was negatively correlated with nicotine dependence or cigarettes/day. CONCLUSIONS Combined with earlier findings, these results suggest a model of changing trajectories whereby FA is higher with tobacco exposure during adolescence and declines with continued smoking in adulthood. This notion is supported by the observation that, at multiple sampling sites, participants who had started smoking earlier in life had higher FA than those who had started later.
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17
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Promising Genetic Biomarkers of Preclinical Alzheimer's Disease: The Influence of APOE and TOMM40 on Brain Integrity. Int J Alzheimers Dis 2012; 2012:421452. [PMID: 22550605 PMCID: PMC3328927 DOI: 10.1155/2012/421452] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/07/2011] [Accepted: 12/12/2011] [Indexed: 01/19/2023] Open
Abstract
Finding biomarkers constitutes a crucial step for early detection of Alzheimer's disease (AD). Brain imaging techniques have revealed structural alterations in the brain that may be phenotypic in preclinical AD. The most prominent polymorphism that has been associated with AD and related neural changes is the Apolipoprotein E (APOE) ε4. The translocase of outer mitochondrial membrane 40 (TOMM40), which is in linkage disequilibrium with APOE, has received increasing attention as a promising gene in AD. TOMM40 also impacts brain areas vulnerable in AD, by downstream apoptotic processes that forego extracellular amyloid beta aggregation. The present paper aims to extend on the mitochondrial influence in AD pathogenesis and we propose a TOMM40-induced disconnection of the medial temporal lobe. Finally, we discuss the possibility of mitochondrial dysfunction being the earliest pathophysiological event in AD, which indeed is supported by recent findings.
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18
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Lane RM, He Y. Butyrylcholinesterase genotype and gender influence Alzheimer's disease phenotype. Alzheimers Dement 2012; 9:e1-73. [PMID: 22402324 DOI: 10.1016/j.jalz.2010.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 09/04/2010] [Accepted: 12/02/2010] [Indexed: 10/28/2022]
Abstract
Retrospective data are presented to support a spectrum of early Alzheimer's disease (AD) along a continuum defined by gender and genotype. The putative neurodegenerative mechanisms driving distinct phenotypes at each end of the spectrum are glial hypoactivity associated with early failure of synaptic cholinergic neurotransmission and glial overactivation associated with loss of neural network connectivity due to accelerated age-related breakdown of myelin. In early AD, male butyrylcholinesterase K-variant carriers with one or two apolipoprotein ɛ4 alleles have prominent medial temporal atrophy, synaptic failure, cognitive decline, and accumulation of aggregated beta-amyloid peptide. Increasing synaptic acetylcholine in damaged but still functional cholinergic synapses improves cognitive symptoms, whereas increasing the ability of glia to support synapses and to clear beta-amyloid peptide might be disease-modifying. Conversely, chronic glial overactivation can also drive degenerative processes and in butyrylcholinesterase K-variant negative females generalized glial overactivation may be the main driver from mild cognitive impairment to AD. Females are more likely than males to have accelerated age-related myelin breakdown, more widespread white matter loss, loss of neural network connectivity, whole brain atrophy, and functional decline. Increasing extracellular acetylcholine levels blocks glial activation, reduces myelin loss and damage to neural network connectivity, and is disease-modifying. Between extremes characterized by gender, genotype, and age, pathophysiology may be mixed and this spectrum may explain much of the heterogeneity of amnestic mild cognitive impairment. Preservation of the functional integrity of the neural network may be an important component of strengthening cognitive reserve and significantly delaying the onset and progression of dementia, particularly in females. Prospective confirmation of these hypotheses is required. Implications for future research and therapeutic opportunities are discussed.
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Affiliation(s)
- Roger M Lane
- Bristol-Myers Squibb Global Clinical Research, Wallingford, CT, USA.
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19
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Tobias MC, O’Neill J, Hudkins M, Bartzokis G, Dean AC, London ED. White-matter abnormalities in brain during early abstinence from methamphetamine abuse. Psychopharmacology (Berl) 2010; 209:13-24. [PMID: 20101394 PMCID: PMC2819660 DOI: 10.1007/s00213-009-1761-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 12/14/2009] [Indexed: 12/30/2022]
Abstract
BACKGROUND Previous studies revealed microstructural abnormalities in prefrontal white matter and corpus callosum of long-term abstinent chronic methamphetamine abusers. In view of the importance of the early abstinence period in treatment retention, we compared 23 methamphetamine-dependent subjects abstinent from methamphetamine for 7-13 days with 18 healthy comparison subjects. As certain metabolic changes in the brain first manifest after early abstinence from methamphetamine, it is also possible that microstructural white-matter abnormalities are not yet present during early abstinence. METHODS Using diffusion tensor imaging at 1.5 T, fractional anisotropy (FA) was measured in prefrontal white matter at four inferior-superior levels parallel to the anterior commissure-posterior commissure (AC-PC) plane. We also sampled FA in the corpus callosum at the midline and at eight bilateral, fiber-tract sites in other regions implicated in effects of methamphetamine. RESULTS The methamphetamine group exhibited lower FA in right prefrontal white matter above the AC-PC plane (11.9% lower; p = 0.007), in midline genu corpus callosum (3.9%; p = 0.019), in left and right midcaudal superior corona radiata (11.0% in both hemispheres, p's = 0.020 and 0.016, respectively), and in right perforant fibers (7.3%; p = 0.025). FA in left midcaudal superior corona radiata was correlated with depressive and generalized psychiatric symptoms within the methamphetamine group. CONCLUSIONS The findings support the idea that methamphetamine abuse produces microstructural abnormalities in white matter underlying and interconnecting prefrontal cortices and hippocampal formation. These effects are already present during the first weeks of abstinence from methamphetamine and are linked to psychiatric symptoms assessed during this period.
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Affiliation(s)
- Marc C. Tobias
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
| | - Joseph O’Neill
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
- Division of Child & Adolescent Psychiatry, Semel Institute for Neurosciences, University of California Los Angeles, 760 Westwood Plaza #58-227A, Los Angeles, CA 90024-1759 USA
| | - Matthew Hudkins
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
| | - George Bartzokis
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
- Brain Research Institute, University of California Los Angeles, Los Angeles, CA USA
- Greater Los Angeles VA Healthcare System, Los Angeles, CA USA
| | - Andrew C. Dean
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
| | - Edythe D. London
- Semel Institute for Neuroscience and Biobehavioral Studies, University of California Los Angeles, Los Angeles, CA USA
- Brain Research Institute, University of California Los Angeles, Los Angeles, CA USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA USA
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20
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Shanks M, Kivipelto M, Bullock R, Lane R. Cholinesterase inhibition: is there evidence for disease-modifying effects? Curr Med Res Opin 2009; 25:2439-46. [PMID: 19678754 DOI: 10.1185/03007990903209332] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cholinesterase inhibitors are broadly established as first-line symptomatic therapy for Alzheimer's disease (AD). Symptomatic effects are mediated by the inhibition of acetyl- and/or butyryl-cholinesterase (AChE and/or BuChE) - the enzymes that degrade acetylcholine (ACh) in the synapse. However, ACh is also found outside the synapse ('extracellular ACh') where, among other activities, it plays a role in controlling inflammation and might impact on pathological changes. OBJECTIVE/SCOPE: New data and clinical findings are reviewed and discussed to build a preliminary case for possible disease-modifying effects of cholinesterase inhibition. FINDINGS Trials seeking to demonstrate disease-modifying effects in subjects with mild cognitive impairment failed to reach their primary endpoints, but these failures might relate to aspects of trial methods and analyses. A re-analysis of one of these trials, using a more sensitive model controlling for factors that predict progression to AD, showed a significant delay in progression to AD with dual cholinesterase inhibition over 3 to 4 years. Taken with other evidence, it is plausible that cholinesterase inhibition might contribute to disease modification. The detection of putative disease-modifying effects may be most easily implemented in certain patient subpopulations, and genotyping studies suggest a particular role for BuChE. CONCLUSION Long-term inhibition of BuChE might be especially important when exploring any disease-modifying effects of cholinesterase inhibitors. Elucidation of the mechanisms involved could provide insights leading to the development of new treatments that modify the development and progression of AD.
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Affiliation(s)
- Michael Shanks
- Clinical Neuroscience Centre, University of Hull, Hull HU6 7RX, UK.
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21
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Bartzokis G. Alzheimer's disease as homeostatic responses to age-related myelin breakdown. Neurobiol Aging 2009; 32:1341-71. [PMID: 19775776 DOI: 10.1016/j.neurobiolaging.2009.08.007] [Citation(s) in RCA: 385] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 08/13/2009] [Accepted: 08/17/2009] [Indexed: 12/11/2022]
Abstract
The amyloid hypothesis (AH) of Alzheimer's disease (AD) posits that the fundamental cause of AD is the accumulation of the peptide amyloid beta (Aβ) in the brain. This hypothesis has been supported by observations that genetic defects in amyloid precursor protein (APP) and presenilin increase Aβ production and cause familial AD (FAD). The AH is widely accepted but does not account for important phenomena including recent failures of clinical trials to impact dementia in humans even after successfully reducing Aβ deposits. Herein, the AH is viewed from the broader overarching perspective of the myelin model of the human brain that focuses on functioning brain circuits and encompasses white matter and myelin in addition to neurons and synapses. The model proposes that the recently evolved and extensive myelination of the human brain underlies both our unique abilities and susceptibility to highly prevalent age-related neuropsychiatric disorders such as late onset AD (LOAD). It regards oligodendrocytes and the myelin they produce as being both critical for circuit function and uniquely vulnerable to damage. This perspective reframes key observations such as axonal transport disruptions, formation of axonal swellings/sphenoids and neuritic plaques, and proteinaceous deposits such as Aβ and tau as by-products of homeostatic myelin repair processes. It delineates empirically testable mechanisms of action for genes underlying FAD and LOAD and provides "upstream" treatment targets. Such interventions could potentially treat multiple degenerative brain disorders by mitigating the effects of aging and associated changes in iron, cholesterol, and free radicals on oligodendrocytes and their myelin.
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Affiliation(s)
- George Bartzokis
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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22
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Bartzokis G, Lu PH, Stewart SB, Oluwadara B, Lucas AJ, Pantages J, Pratt E, Sherin JE, Altshuler LL, Mintz J, Gitlin MJ, Subotnik KL, Nuechterlein KH. In vivo evidence of differential impact of typical and atypical antipsychotics on intracortical myelin in adults with schizophrenia. Schizophr Res 2009; 113:322-31. [PMID: 19616412 PMCID: PMC2862048 DOI: 10.1016/j.schres.2009.06.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 06/13/2009] [Accepted: 06/16/2009] [Indexed: 10/20/2022]
Abstract
CONTEXT Imaging and post-mortem studies provide converging evidence that patients with schizophrenia have a dysregulated developmental trajectory of frontal lobe myelination. The hypothesis that typical and atypical medications may differentially impact brain myelination in adults with schizophrenia was previously assessed with inversion recovery (IR) images. Increased white matter (WM) volume suggestive of increased myelination was detected in the patient group treated with an atypical antipsychotic compared to a typical one. OBJECTIVE In a follow-up reanalysis of MRI images from the original study, we used a novel method to assess whether the difference in WM volumes could be caused by a differential effect of medications on the intracortical myelination process. DESIGN, SETTING, AND PARTICIPANTS Two different male cohorts of healthy controls ranging in age from 18-35 years were compared to cohorts of subjects with schizophrenia who were treated with either oral risperidone (Ris) or fluphenazine decanoate (Fd). MAIN OUTCOME MEASURE A novel MRI method that combines the distinct tissue contrasts provided by IR and proton density (PD) images was used to estimate intracortical myelin (ICM) volume. RESULTS When compared with their pooled healthy control comparison group, the two groups of schizophrenic patients differed in the frontal lobe ICM measure with the Ris group having significantly higher volume. CONCLUSIONS The data suggest that in adults with schizophrenia antipsychotic treatment choice may be specifically and differentially impacting later-myelinating intracortical circuitry. In vivo MRI can be used to dissect subtle differences in brain tissue characteristics and thus help clarify the effect of pharmacologic treatments on developmental and pathologic processes.
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Affiliation(s)
- George Bartzokis
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-6968, USA.
| | - Po H. Lu
- Department of Neurology, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Stephanie B. Stewart
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Bolanle Oluwadara
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California.,Greater Los Angeles VA Healthcare System, West Los Angeles, California
| | - Andrew J. Lucas
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Joanna Pantages
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California.,Greater Los Angeles VA Healthcare System, West Los Angeles, California
| | - Erika Pratt
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California.,Greater Los Angeles VA Healthcare System, West Los Angeles, California
| | - Jonathan E. Sherin
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California.,Greater Los Angeles VA Healthcare System, West Los Angeles, California
| | - Lori L. Altshuler
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California.,Greater Los Angeles VA Healthcare System, West Los Angeles, California
| | - Jim Mintz
- University of Texas Health Science Center at San Antonio, Department of Epidemiology and Biostatistics, San Antonio, Texas
| | - Michael J. Gitlin
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Kenneth L. Subotnik
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Keith H. Nuechterlein
- Department of Psychiatry and Biobehavioral Sciences, The David Geffen School of Medicine at UCLA, Los Angeles, California
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23
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Dickinson D, Harvey PD. Systemic hypotheses for generalized cognitive deficits in schizophrenia: a new take on an old problem. Schizophr Bull 2009; 35:403-14. [PMID: 18689868 PMCID: PMC2659304 DOI: 10.1093/schbul/sbn097] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The schizophrenia research community, including government, industry, and academia, has made development of procognitive treatment strategies a priority. Much current research is directed at dividing broad impairments in cognition into more delineated components that might correspond to relatively specific neural systems and serve as targets for intervention. Sometimes overlooked in this ambitious agenda is the substantial neuropsychological literature that signals a more broadly generalized dysfunction in higher order cognitive functions in this illness. In this article, we argue that a generalized cognitive deficit is at the core of the disorder, is not a methodological artifact, and deserves more focused consideration from cognitive specialists in the field. Further, we weigh evidence that this broad deficit may have systemic biological underpinnings. At the level of the central nervous system, examples of findings that might help to account for broad cognitive impairment include gray and white matter irregularities, poor signal integration by neurons and neural networks, and abnormalities in glutamate and gamma-aminobutyric acid neurotransmission. Other, more speculative hypotheses focus on even broader somatic systems, including energy metabolism and inflammatory processes. Treatment implications of systemic conceptualizations of schizophrenia are also considered.
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Affiliation(s)
| | - Philip D. Harvey
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA
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24
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Lifespan trajectory of myelin integrity and maximum motor speed. Neurobiol Aging 2008; 31:1554-62. [PMID: 18926601 DOI: 10.1016/j.neurobiolaging.2008.08.015] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 07/26/2008] [Accepted: 08/21/2008] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Myelination of the human brain results in roughly quadratic trajectories of myelin content and integrity, reaching a maximum in mid-life and then declining in older age. This trajectory is most evident in vulnerable later myelinating association regions such as frontal lobes and may be the biological substrate for similar trajectories of cognitive processing speed. Speed of movement, such as maximal finger tapping speed (FTS), requires high-frequency action potential (AP) bursts and is associated with myelin integrity. We tested the hypothesis that the age-related trajectory of FTS is related to brain myelin integrity. METHODS A sensitive in vivo MRI biomarker of myelin integrity (calculated transverse relaxation rates (R(2))) of frontal lobe white matter (FLwm) was measured in a sample of very healthy males (N=72) between 23 and 80 years of age. To assess specificity, R(2) of a contrasting early-myelinating region (splenium of the corpus callosum) was also measured. RESULTS FLwm R(2) and FTS measures were significantly correlated (r=.45, p<.0001) with no association noted in the early-myelinating region (splenium). Both FLwm R(2) and FTS had significantly quadratic lifespan trajectories that were virtually indistinguishable and both reached a peak at 39 years of age and declined with an accelerating trajectory thereafter. CONCLUSIONS The results suggest that in this very healthy male sample, maximum motor speed requiring high-frequency AP burst may depend on brain myelin integrity. To the extent that the FLwm changes assessed by R(2) contribute to an age-related reduction in AP burst frequency, it is possible that other brain functions dependent on AP bursts may also be affected. Non-invasive measures of myelin integrity together with testing of basic measures of processing speed may aid in developing and targeting anti-aging treatments to mitigate age-related functional declines.
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Increased NAA and reduced choline levels in the anterior cingulum following chronic methylphenidate. A spectroscopic test-retest study in adult ADHD. Eur Arch Psychiatry Clin Neurosci 2008; 258:446-50. [PMID: 18330668 DOI: 10.1007/s00406-008-0810-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 12/11/2007] [Indexed: 01/27/2023]
Abstract
The anterior cingulate cortex (ACC) is crucially involved in executive control of attention. Here, seven medication-naïve adult patients suffering from attention deficit/hyperactivity disorder (ADHD) were studied with 2D (1)H-magnetic resonance spectroscopic imaging (MRSI) of the ACC [Brodmann areas 24b'-c' and 32'] twice, once before initiation of stimulant treatment and once after 5-6 weeks of methylphenidate. Upon retest, all patients demonstrated marked clinical improvement. Analysis of regional brain spectra revealed a significantly decreased signal of choline containing compounds as well as increased N-acetyl-aspartate (NAA) levels following treatment with methylphenidate whereas total creatine remained unchanged. Our results add to a growing body of evidence implicating the ACC in the pathophysiology of ADHD and suggest that subtle structural changes might be associated with aspects of clinical improvement under stimulant treatment.
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Pre‐treatment with ebselen and vitamin E modulate acetylcholinesterase activity: interaction with demyelinating agents. Int J Dev Neurosci 2008; 27:73-80. [DOI: 10.1016/j.ijdevneu.2008.09.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 09/05/2008] [Accepted: 09/23/2008] [Indexed: 11/23/2022] Open
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27
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Colla M, Ende G, Alm B, Deuschle M, Heuser I, Kronenberg G. Cognitive MR spectroscopy of anterior cingulate cortex in ADHD: elevated choline signal correlates with slowed hit reaction times. J Psychiatr Res 2008; 42:587-95. [PMID: 17698080 DOI: 10.1016/j.jpsychires.2007.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 06/17/2007] [Accepted: 06/19/2007] [Indexed: 11/23/2022]
Abstract
The anterior cingulate cortex (ACC) plays a major role in modulating executive control of attention. Here, 15 medication-nai ve patients with attention deficit/hyperactivity disorder (ADHD) and 10 carefully matched healthy controls were studied with 2D (1)H-magnetic resonance spectroscopic imaging (MRSI) of the ACC [Brodmann areas 24b'-c' and 32']. Attentional skills were assessed using the identical pairs version of the continuous performance task (CPT-IP). Analysis of regional brain spectra revealed a significantly increased signal of choline-containing compounds (Ch) in the ACC of ADHD patients (p<0.05). Across and within groups, the Ch signal showed high correlations with slowed hit reaction times on the CPT-IP. No group differences in N-acetyl-aspartate (NAA) and creatine (tCr) were detectable. The combination of performance deficits and elevated Ch levels in the ACC supports the hypothesis that subtle structural abnormalities underlie the functional alterations in ACC activation previously observed in ADHD patients.
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Affiliation(s)
- Michael Colla
- Department of Psychiatry, Charité-University Medicine Berlin, Campus Benjamin Franklin, Eschenallee 3, 14050 Berlin, Germany.
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Le-Niculescu H, McFarland MJ, Mamidipalli S, Ogden CA, Kuczenski R, Kurian SM, Salomon DR, Tsuang MT, Nurnberger JI, Niculescu AB. Convergent Functional Genomics of bipolar disorder: from animal model pharmacogenomics to human genetics and biomarkers. Neurosci Biobehav Rev 2007; 31:897-903. [PMID: 17614132 PMCID: PMC3313450 DOI: 10.1016/j.neubiorev.2007.05.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 05/10/2007] [Accepted: 05/19/2007] [Indexed: 01/12/2023]
Abstract
Progress in understanding the genetic and neurobiological basis of bipolar disorder(s) has come from both human studies and animal model studies. Until recently, the lack of concerted integration between the two approaches has been hindering the pace of discovery, or more exactly, constituted a missed opportunity to accelerate our understanding of this complex and heterogeneous group of disorders. Our group has helped overcome this "lost in translation" barrier by developing an approach called convergent functional genomics (CFG). The approach integrates animal model gene expression data with human genetic linkage/association data, as well as human tissue (postmortem brain, blood) data. This Bayesian strategy for cross-validating findings extracts meaning from large datasets, and prioritizes candidate genes, pathways and mechanisms for subsequent targeted, hypothesis-driven research. The CFG approach may also be particularly useful for identification of blood biomarkers of the illness.
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Affiliation(s)
- H. Le-Niculescu
- Laboratory of Neurophenomics, Indiana University School of Medicine, Indianapolis, IN
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN
| | - M. J. McFarland
- Laboratory of Neurophenomics, Indiana University School of Medicine, Indianapolis, IN
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN
| | - S. Mamidipalli
- Laboratory of Neurophenomics, Indiana University School of Medicine, Indianapolis, IN
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN
| | - C. A. Ogden
- Drexel University College of Medicine, Philadelphia, PA
| | - R. Kuczenski
- Department of Psychiatry, UC San Diego, La Jolla, CA
| | - S. M. Kurian
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - D. R. Salomon
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | | | - J. I. Nurnberger
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN
| | - A. B. Niculescu
- Laboratory of Neurophenomics, Indiana University School of Medicine, Indianapolis, IN
- INBRAIN, Indiana University School of Medicine, Indianapolis, IN
- Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN
- R. L. Roudebush VA Medical Center, Indianapolis, IN
- Corresponding author, E-mail:
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