1
|
Ramakrishnan V, Friedrich C, Witt C, Sheehan R, Pryor M, Atwal JK, Wildsmith K, Kudrycki K, Lee S, Mazer N, Hofmann C, Fuji RN, Jin J, Ramanujan S, Dolton M, Quartino A. Quantitative systems pharmacology model of the amyloid pathway in Alzheimer's disease: Insights into the therapeutic mechanisms of clinical candidates. CPT Pharmacometrics Syst Pharmacol 2022; 12:62-73. [PMID: 36281062 PMCID: PMC9835125 DOI: 10.1002/psp4.12876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/06/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022] Open
Abstract
Despite considerable investment into potential therapeutic approaches for Alzheimer's disease (AD), currently approved treatment options are limited. Predictive modeling using quantitative systems pharmacology (QSP) can be used to guide the design of clinical trials in AD. This study developed a QSP model representing amyloid beta (Aβ) pathophysiology in AD. The model included mechanisms of Aβ monomer production and aggregation to form insoluble fibrils and plaques; the transport of soluble species between the compartments of brain, cerebrospinal fluid (CSF), and plasma; and the pharmacokinetics, transport, and binding of monoclonal antibodies to targets in the three compartments. Ordinary differential equations were used to describe these processes quantitatively. The model components were calibrated to data from the literature and internal studies, including quantitative data supporting the underlying AD biology and clinical data from clinical trials for anti-Aβ monoclonal antibodies (mAbs) aducanumab, crenezumab, gantenerumab, and solanezumab. The model was developed for an apolipoprotein E (APOE) ɛ4 allele carrier and tested for an APOE ɛ4 noncarrier. Results indicate that the model is consistent with data on clinical Aβ accumulation in untreated individuals and those treated with monoclonal antibodies, capturing increases in Aβ load accurately. This model may be used to investigate additional AD mechanisms and their impact on biomarkers, as well as predict Aβ load at different dose levels for mAbs with known targets and binding affinities. This model may facilitate the design of scientifically enriched and efficient clinical trials by enabling a priori prediction of biomarker dynamics in the brain and CSF.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Jin Y. Jin
- Genentech, Inc.South San FranciscoCaliforniaUSA
| | | | - Michael Dolton
- Roche Products Australia Pty LtdNew South WalesSydneyAustralia
| | | |
Collapse
|
2
|
Popuri K, Ma D, Wang L, Beg MF. Using machine learning to quantify structural MRI neurodegeneration patterns of Alzheimer's disease into dementia score: Independent validation on 8,834 images from ADNI, AIBL, OASIS, and MIRIAD databases. Hum Brain Mapp 2020; 41:4127-4147. [PMID: 32614505 PMCID: PMC7469784 DOI: 10.1002/hbm.25115] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 04/15/2020] [Accepted: 06/08/2020] [Indexed: 12/29/2022] Open
Abstract
Biomarkers for dementia of Alzheimer's type (DAT) are sought to facilitate accurate prediction of the disease onset, ideally predating the onset of cognitive deterioration. T1-weighted magnetic resonance imaging (MRI) is a commonly used neuroimaging modality for measuring brain structure in vivo, potentially providing information enabling the design of biomarkers for DAT. We propose a novel biomarker using structural MRI volume-based features to compute a similarity score for the individual's structural patterns relative to those observed in the DAT group. We employed ensemble-learning framework that combines structural features in most discriminative ROIs to create an aggregate measure of neurodegeneration in the brain. This classifier is trained on 423 stable normal control (NC) and 330 DAT subjects, where clinical diagnosis is likely to have the highest certainty. Independent validation on 8,834 unseen images from ADNI, AIBL, OASIS, and MIRIAD Alzheimer's disease (AD) databases showed promising potential to predict the development of DAT depending on the time-to-conversion (TTC). Classification performance on stable versus progressive mild cognitive impairment (MCI) groups achieved an AUC of 0.81 for TTC of 6 months and 0.73 for TTC of up to 7 years, achieving state-of-the-art results. The output score, indicating similarity to patterns seen in DAT, provides an intuitive measure of how closely the individual's brain features resemble the DAT group. This score can be used for assessing the presence of AD structural atrophy patterns in normal aging and MCI stages, as well as monitoring the progression of the individual's brain along with the disease course.
Collapse
Affiliation(s)
- Karteek Popuri
- School of Engineering ScienceSimon Fraser UniversityBarnabyBritish ColumbiaCanada
| | - Da Ma
- School of Engineering ScienceSimon Fraser UniversityBarnabyBritish ColumbiaCanada
| | - Lei Wang
- Feinberg School of MedicineNorthwestern UniversityEvanstonIllinoisUSA
| | - Mirza Faisal Beg
- School of Engineering ScienceSimon Fraser UniversityBarnabyBritish ColumbiaCanada
| |
Collapse
|
3
|
Srivastava AK, Pittman JM, Zerweck J, Venkata BS, Moore PC, Sachleben JR, Meredith SC. β-Amyloid aggregation and heterogeneous nucleation. Protein Sci 2019; 28:1567-1581. [PMID: 31276610 PMCID: PMC6699094 DOI: 10.1002/pro.3674] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 01/09/2023]
Abstract
In this article, we consider the role of heterogeneous nucleation in β-amyloid aggregation. Heterogeneous nucleation is more common and occurs at lower levels of supersaturation than homogeneous nucleation. The nucleation period is also the stage at which most of the polymorphism of amyloids arises, this being one of the defining features of amyloids. We focus on several well-known heterogeneous nucleators of β-amyloid, including lipid surfaces, especially those enriched in gangliosides and cholesterol, and divalent metal ions. These two broad classes of nucleators affect β-amyloid particularly in light of the amphiphilicity of these peptides: the N-terminal region, which is largely polar and charged, contains the metal binding site, whereas the C-terminal region is aliphatic and is important in lipid binding. Notably, these two classes of nucleators can interact cooperatively, aggregation begetting greater aggregation.
Collapse
Affiliation(s)
- Atul K. Srivastava
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Jay M. Pittman
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Jonathan Zerweck
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Bharat S. Venkata
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | | | | | - Stephen C. Meredith
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| |
Collapse
|
4
|
Mondal S, Kumar V, Roy Chowdhury S, Shah M, Gaur A, Kumar S, Iyer PK. Template-Mediated Detoxification of Low-Molecular-Weight Amyloid Oligomers and Regulation of Their Nucleation Pathway. ACS APPLIED BIO MATERIALS 2019; 2:5306-5312. [DOI: 10.1021/acsabm.9b00514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
5
|
Jiang L, Oualkacha K, Didelez V, Ciampi A, Rosa-Neto P, Benedet AL, Mathotaarachchi S, Richards JB, Greenwood CMT. Constrained instruments and their application to Mendelian randomization with pleiotropy. Genet Epidemiol 2019; 43:373-401. [PMID: 30635941 PMCID: PMC6537099 DOI: 10.1002/gepi.22184] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/11/2018] [Accepted: 12/02/2018] [Indexed: 01/31/2023]
Abstract
In Mendelian randomization (MR), inference about causal relationship between a phenotype of interest and a response or disease outcome can be obtained by constructing instrumental variables from genetic variants. However, MR inference requires three assumptions, one of which is that the genetic variants only influence the outcome through phenotype of interest. Pleiotropy, that is, the situation in which some genetic variants affect more than one phenotype, can invalidate these genetic variants for use as instrumental variables; thus a naive analysis will give biased estimates of the causal relation. Here, we present new methods (constrained instrumental variable [CIV] methods) to construct valid instrumental variables and perform adjusted causal effect estimation when pleiotropy exists and when the pleiotropic phenotypes are available. We demonstrate that a smoothed version of CIV performs approximate selection of genetic variants that are valid instruments, and provides unbiased estimates of the causal effects. We provide details on a number of existing methods, together with a comparison of their performance in a large series of simulations. CIV performs robustly across different pleiotropic violations of the MR assumptions. We also analyzed the data from the Alzheimer’s disease (AD) neuroimaging initiative (ADNI; Mueller et al., 2005. Alzheimer's Dementia, 11(1), 55–66) to disentangle causal relationships of several biomarkers with AD progression.
Collapse
Affiliation(s)
- Lai Jiang
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.,Department of Epidemiology, Biostatistics and Occupational Health and Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Karim Oualkacha
- Department of Mathematics, Université du Québec à Montréal, Montreal, Quebec, Canada
| | - Vanessa Didelez
- BIPS & Department of Mathematics, Leibinz Institute for Prevention Research and Epidemiology, University of Bremen, Bremen, Germany
| | - Antonio Ciampi
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.,Department of Epidemiology, Biostatistics and Occupational Health and Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Pedro Rosa-Neto
- Department of Neurology & Neurosurgery, McGill University, Montreal, Quebec, Canada.,Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Douglas Hospital, McGill University, Montreal, Quebec, Canada
| | - Andrea L Benedet
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Douglas Hospital, McGill University, Montreal, Quebec, Canada
| | - Sulantha Mathotaarachchi
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, Douglas Hospital, McGill University, Montreal, Quebec, Canada
| | | | - Celia M T Greenwood
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.,Department of Epidemiology, Biostatistics and Occupational Health and Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | | |
Collapse
|
6
|
Rizzi L, Maria Portal M, Batista CEA, Missiaggia L, Roriz-Cruz M. CSF Aβ1–42, but not p-Tau181, differentiates aMCI from SCI. Brain Res 2018; 1678:27-31. [DOI: 10.1016/j.brainres.2017.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 08/26/2017] [Accepted: 10/04/2017] [Indexed: 12/14/2022]
|
7
|
Better Utilization of Mouse Models of Neurodegenerative Diseases in Preclinical Studies: From the Bench to the Clinic. Methods Mol Biol 2016; 1438:311-47. [PMID: 27150098 DOI: 10.1007/978-1-4939-3661-8_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The major symptom of Alzheimer's disease is dementia progressing with age. Its clinical diagnosis is preceded by a long prodromal period of brain pathology that encompasses both formation of extracellular amyloid and intraneuronal tau deposits in the brain and widespread neuronal death. At present, familial cases of dementia provide the most promising foundation for modeling neurodegenerative tauopathies, a group of heterogeneous disorders characterized by prominent intracellular accumulation of hyperphosphorylated tau protein. In this chapter, we describe major behavioral hallmarks of tauopathies, briefly outline the genetics underlying familial cases, and discuss the arising implications for modeling the disease in transgenic mouse systems. The selection of tests performed to evaluate the phenotype of a model should be guided by the key behavioral hallmarks that characterize human disorder and their homology to mouse cognitive systems. We attempt to provide general guidelines and establish criteria for modeling dementia in a mouse; however, interpretations of obtained results should avoid a reductionist "one gene, one disease" explanation of model characteristics. Rather, the focus should be directed to the question of how the mouse genome can cope with the over-expression of the protein coded by transgene(s). While each model is valuable within its own constraints and the experiments performed are guided by specific hypotheses, we seek to expand upon their methodology by offering guidance spanning from issues of mouse husbandry to choices of behavioral tests and routes of drug administration that might increase the external validity of studies and consequently optimize the translational aspect of preclinical research.
Collapse
|
8
|
Mo JA, Lim JH, Sul AR, Lee M, Youn YC, Kim HJ. Cerebrospinal fluid β-amyloid1-42 levels in the differential diagnosis of Alzheimer's disease--systematic review and meta-analysis. PLoS One 2015; 10:e0116802. [PMID: 25710596 PMCID: PMC4339391 DOI: 10.1371/journal.pone.0116802] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 12/15/2014] [Indexed: 01/01/2023] Open
Abstract
Objectives The purpose of this study was to carry out systematic review of the literature and meta-analysis to evaluate the diagnostic utility of cerebrospinal fluid (CSF) levels of the 42 amino acid form of amyloid-beta (Aβ1–42) as a biomarker for differentiating Alzheimer’s disease (AD) from non-AD dementia. Methods Design. Systematic literature review was used to evaluate the effectiveness of the Aβ for the diagnosis of AD. The Scottish Intercollegiate Guidelines Network (SIGN) tool was used to evaluate independently the quality of the studies. Data sources. The literature review covered from January 1, 2004, to October 22, 2013, and searched eight domestic databases including Korea Med and international databases including Ovid-MEDLINE, EMBASE, and Cochrane Library. Data Extraction and Synthesis. Primary criteria for inclusion were valid studies on (i) patients with mild cognitive impairment with confirmed or suspected AD and non-AD dementia, and (ii) assessment of Aβ1–42 levels using appropriate comparative tests. Results A total of 17 diagnostic evaluation studies were identified in which levels of CSF Aβ1–42 were assessed. Meta-analysis was performed on 11 robust studies that compared confirmed AD (n = 2211) with healthy individuals (n = 1030), 10 studies that compared AD with non-AD dementias (n = 627), and 5 studies that compared amnestic mild cognitive impairment (n = 1133) with non-amnestic type subjects (n = 1276). Overall, the CSF Aβ1–42 levels were reduced in AD compared to controls or non-AD dementia. The effectiveness of test was evaluated for diagnostic accuracy (pooled sensitivity, 0.80 (95% CI 0.78–0.82); pooled specificity, 0.76 (95% CI 0.74–0.78). Conclusions Reduced CSF Aβ1–42 levels are of potential utility in the differential diagnosis of AD versus non-AD dementias and controls. Diagnostic accuracy was high in AD versus healthy controls. However, differential diagnosis for MCI or non-AD might be evaluated by other biomarkers.
Collapse
Affiliation(s)
- Jin-A Mo
- National Evidence-Based Health Care Collaborating Agency, Seoul, Korea
- Department of Nursing, Inha University College of Medicine, Incheon, Korea
| | - Ju-Hee Lim
- National Evidence-Based Health Care Collaborating Agency, Seoul, Korea
| | - Ah-Ram Sul
- National Evidence-Based Health Care Collaborating Agency, Seoul, Korea
| | - Min Lee
- National Evidence-Based Health Care Collaborating Agency, Seoul, Korea
| | - Young Chul Youn
- Department of Neurology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Hee-Jin Kim
- Department of Neurology, Hanyang University College of Medicine, Seoul, Korea
- * E-mail:
| |
Collapse
|
9
|
Tang W, Huang Q, Wang Y, Wang ZY, Yao YY. Assessment of CSF Aβ42 as an aid to discriminating Alzheimer's disease from other dementias and mild cognitive impairment: a meta-analysis of 50 studies. J Neurol Sci 2014; 345:26-36. [PMID: 25086857 DOI: 10.1016/j.jns.2014.07.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/27/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023]
Abstract
Mild Alzheimer's disease (AD) is usually difficult to differentiate from other dementias or mild cognitive impairment (MCI). The aim of our study is to evaluate the clinical importance of cerebrospinal fluid (CSF) β-amyloid 42 (Aβ42) in MCI, AD and other dementias, more specifically: frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), Parkinson's disease (PD) with dementia (PDD) and vascular dementia (VaD). Fifty eligible articles were identified by search of databases including PubMed, EMBASE, Elsevier, Springer Link and the Cochrane Library, from January 1990 to May 2014. The random effects model was used to calculate the standardized mean difference (SMD) with corresponding 95% CI by STATA 9.0 software. The subgroup analyses were made on the method (ELISA, xMAP). We found that CSF Aβ42 concentrations were significantly lower in AD compared to MCI (SMD: -0.68, 95% CI: [-0.80, -0.56], z=11.34, P<0.001), FTD (SMD: -1.09, 95% CI: [-1.41, -0.76], z=6.62, P<0.001), PDD (SMD: -0.75, 95% CI: [-1.39, -0.10], z=2.27, P=0.023), VaD (SMD: -0.95, 95% CI: [-1.30, -0.61], z=5.43, P<0.001). In addition, compared to DLB, Aβ42 concentrations are moderately lower in AD (SMD: -0.27, 95% CI: [-0.51, -0.03], z=2.20, P=0.028). Results from this meta-analysis hinted that CSF Aβ42 is a good biomarker for discriminating Alzheimer's disease from other dementias and MCI.
Collapse
Affiliation(s)
- Wei Tang
- Department of Clinical Laboratory Medicine, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei 230032, Anhui, China
| | - Qiong Huang
- AnQing City Affiliated Hospital of Anhui Medical University, No. 352 Renmin Road, AnQing 246003, Anhui, China
| | - Yan Wang
- Department of General Surgery, The Second Affiliated Hospital of Anhui Medical University, No. 678 Furong Road, Hefei 230601, Anhui, China
| | - Zheng-Yu Wang
- Department of Clinical Laboratory Medicine, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei 230032, Anhui, China
| | - Yu-You Yao
- Department of Clinical Laboratory Medicine, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Hefei 230032, Anhui, China.
| |
Collapse
|
10
|
Ritchie C, Smailagic N, Noel‐Storr AH, Takwoingi Y, Flicker L, Mason SE, McShane R. Plasma and cerebrospinal fluid amyloid beta for the diagnosis of Alzheimer's disease dementia and other dementias in people with mild cognitive impairment (MCI). Cochrane Database Syst Rev 2014; 2014:CD008782. [PMID: 24913723 PMCID: PMC6465069 DOI: 10.1002/14651858.cd008782.pub4] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND According to the latest revised National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (now known as the Alzheimer's Association) (NINCDS-ADRDA) diagnostic criteria for Alzheimer's disease dementia of the National Institute on Aging and Alzheimer Association, the confidence in diagnosing mild cognitive impairment (MCI) due to Alzheimer's disease dementia is raised with the application of biomarkers based on measures in the cerebrospinal fluid (CSF) or imaging. These tests, added to core clinical criteria, might increase the sensitivity or specificity of a testing strategy. However, the accuracy of biomarkers in the diagnosis of Alzheimer's disease dementia and other dementias has not yet been systematically evaluated. A formal systematic evaluation of sensitivity, specificity, and other properties of plasma and CSF amyloid beta (Aß) biomarkers was performed. OBJECTIVES To determine the accuracy of plasma and CSF Aß levels for detecting those patients with MCI who would convert to Alzheimer's disease dementia or other forms of dementia over time. SEARCH METHODS The most recent search for this review was performed on 3 December 2012. We searched MEDLINE (OvidSP), EMBASE (OvidSP), BIOSIS Previews (ISI Web of Knowledge), Web of Science and Conference Proceedings (ISI Web of Knowledge), PsycINFO (OvidSP), and LILACS (BIREME). We also requested a search of the Cochrane Register of Diagnostic Test Accuracy Studies (managed by the Cochrane Renal Group).No language or date restrictions were applied to the electronic searches and methodological filters were not used so as to maximise sensitivity. SELECTION CRITERIA We selected those studies that had prospectively well defined cohorts with any accepted definition of cognitive decline, but no dementia, with baseline CSF or plasma Aß levels, or both, documented at or around the time the above diagnoses were made. We also included studies which looked at data from those cohorts retrospectively, and which contained sufficient data to construct two by two tables expressing plasma and CSF Aß biomarker results by disease status. Moreover, studies were only selected if they applied a reference standard for Alzheimer's dementia diagnosis, for example the NINCDS-ADRDA or Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. DATA COLLECTION AND ANALYSIS We screened all titles generated by the electronic database searches. Two review authors independently assessed the abstracts of all potentially relevant studies. We assessed the identified full papers for eligibility and extracted data to create standard two by two tables. Two independent assessors performed quality assessment using the QUADAS-2 tool. Where data allowed, we derived estimates of sensitivity at fixed values of specificity from the model we fitted to produce the summary receiver operating characteristic (ROC) curve. MAIN RESULTS Alzheimer's disease dementia was evaluated in 14 studies using CSF Aß42. Of the 1349 participants included in the meta-analysis, 436 developed Alzheimer's dementia. Individual study estimates of sensitivity were between 36% and 100% while the specificities were between 29% and 91%. Because of the variation in assay thresholds, we did not estimate summary sensitivity and specificity. However, we derived estimates of sensitivity at fixed values of specificity from the model we fitted to produce the summary ROC curve. At the median specificity of 64%, the sensitivity was 81% (95% CI 72 to 87). This equated to a positive likelihood ratio (LR+) of 2.22 (95% CI 2.00 to 2.47) and a negative likelihood ratio (LR-) of 0.31 (95% CI 0.21 to 0.48).The accuracy of CSF Aß42 for all forms of dementia was evaluated in four studies. Of the 464 participants examined, 188 developed a form of dementia (Alzheimer's disease and other forms of dementia).The thresholds used were between 209 mg/ml and 512 ng/ml. The sensitivities were between 56% and 75% while the specificities were between 47% and 76%. At the median specificity of 75%, the sensitivity was estimated to be 63% (95% CI 22 to 91) from the meta-analytic model. This equated to a LR+ of 2.51 (95% CI 1.30 to 4.86) and a LR- of 0.50 (95% CI 0.16 to 1.51).The accuracy of CSF Aß42 for non-Alzheimer's disease dementia was evaluated in three studies. Of the 385 participants examined, 61 developed non-Alzheimer's disease dementia. Since there were very few studies and considerable variation between studies, the results were not meta-analysed. The sensitivities were between 8% and 63% while the specificities were between 35% and 67%.Only one study examined the accuracy of plasma Aß42 and the plasma Aß42/Aß40 ratio for Alzheimer's disease dementia. The sensitivity of 86% (95% CI 81 to 90) was the same for both tests while the specificities were 50% (95% CI 44 to 55) and 70% (95% CI 64 to 75) for plasma Aß42 and the plasma Aß42/Aß40 ratio respectively. Of the 565 participants examined, 245 developed Alzheimer's dementia and 87 non-Alzheimer's disease dementia.There was substantial heterogeneity between studies. The accuracy of Aß42 for the diagnosis of Alzheimer's disease dementia did not differ significantly (P = 0.8) between studies that pre-specified the threshold for determining test positivity (n = 6) and those that only determined the threshold at follow-up (n = 8). One study excluded a sample of MCI non-Alzheimer's disease dementia converters from their analysis. In sensitivity analyses, the exclusion of this study had no impact on our findings. The exclusion of eight studies (950 patients) that were considered at high (n = 3) or unclear (n = 5) risk of bias for the patient selection domain also made no difference to our findings. AUTHORS' CONCLUSIONS The proposed diagnostic criteria for prodromal dementia and MCI due to Alzheimer's disease, although still being debated, would be fulfilled where there is both core clinical and cognitive criteria and a single biomarker abnormality. From our review, the measure of abnormally low CSF Aß levels has very little diagnostic benefit with likelihood ratios suggesting only marginal clinical utility. The quality of reports was also poor, and thresholds and length of follow-up were inconsistent. We conclude that when applied to a population of patients with MCI, CSF Aß levels cannot be recommended as an accurate test for Alzheimer's disease.
Collapse
Affiliation(s)
| | - Nadja Smailagic
- University of CambridgeInstitute of Public HealthForvie SiteRobinson WayCambridgeUKCB2 0SR
| | - Anna H Noel‐Storr
- University of OxfordRadcliffe Department of MedicineRoom 4401c (4th Floor)John Radcliffe Hospital, HeadingtonOxfordUKOX3 9DU
| | - Yemisi Takwoingi
- University of BirminghamPublic Health, Epidemiology and BiostatisticsEdgbastonBirminghamUKB15 2TT
| | - Leon Flicker
- University of Western AustraliaWestern Australian Centre for Health & Ageing ‐ WACHACrawleyPerthWestern AustraliaAustralia6014
| | | | - Rupert McShane
- University of OxfordRadcliffe Department of MedicineRoom 4401c (4th Floor)John Radcliffe Hospital, HeadingtonOxfordUKOX3 9DU
| | | |
Collapse
|
11
|
Forlenza OV, Diniz BS, Teixeira AL, Stella F, Gattaz W. Mild cognitive impairment. Part 2: Biological markers for diagnosis and prediction of dementia in Alzheimer's disease. BRAZILIAN JOURNAL OF PSYCHIATRY 2014; 35:284-94. [PMID: 24142092 DOI: 10.1590/1516-4446-2012-3505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 09/08/2012] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To present a critical review of publications reporting on the rationale and clinical implications of the use of biomarkers for the early diagnosis of Alzheimer's disease (AD). METHODS We conducted a systematic search of the PubMed and Web of Science electronic databases, limited to articles published in English between 1999 and 2012, and based on the following terms: mild cognitive impairment, Alzheimer's disease OR dementia, biomarkers. We retrieved 1,130 articles, of which 175 were reviews. Overall, 955 original articles were eligible. RESULTS The following points were considered relevant for the present review: a) rationale for biomarkers research in AD and mild cognitive impairment (MCI); b) usefulness of distinct biomarkers for the diagnosis and prediction of AD; c) the role of multimodality biomarkers for the diagnosis and prediction of AD; d) the role of biomarkers in clinical trials of patients with AD and MCI; and e) current limitations to the widespread use of biomarkers in research and clinical settings. CONCLUSION Different biomarkers are useful for the early diagnosis and prediction of AD in at-risk subjects. Nonetheless, important methodological limitations need to be overcome for widespread use of biomarkers in research and clinical settings.
Collapse
Affiliation(s)
- Orestes V Forlenza
- Universidade de São Paulo, Laboratory of Neuroscience, Department and Institute of Psychiatry, School of Medicine, São PauloSP, Brazil
| | | | | | | | | |
Collapse
|
12
|
Al-Hilaly YK, Williams TL, Stewart-Parker M, Ford L, Skaria E, Cole M, Bucher WG, Morris KL, Sada AA, Thorpe JR, Serpell LC. A central role for dityrosine crosslinking of Amyloid-β in Alzheimer's disease. Acta Neuropathol Commun 2013; 1:83. [PMID: 24351276 PMCID: PMC3880074 DOI: 10.1186/2051-5960-1-83] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/07/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by the deposition of insoluble amyloid plaques in the neuropil composed of highly stable, self-assembled Amyloid-beta (Aβ) fibrils. Copper has been implicated to play a role in Alzheimer's disease. Dimers of Aβ have been isolated from AD brain and have been shown to be neurotoxic. RESULTS We have investigated the formation of dityrosine cross-links in Aβ42 formed by covalent ortho-ortho coupling of two tyrosine residues under conditions of oxidative stress with elevated copper and shown that dityrosine can be formed in vitro in Aβ oligomers and fibrils and that these links further stabilize the fibrils. Dityrosine crosslinking was present in internalized Aβ in cell cultures treated with oligomeric Aβ42 using a specific antibody for dityrosine by immunogold labeling transmission electron microscopy. Results also revealed the prevalence of dityrosine crosslinks in amyloid plaques in brain tissue and in cerebrospinal fluid from AD patients. CONCLUSIONS Aβ dimers may be stabilized by dityrosine crosslinking. These results indicate that dityrosine cross-links may play an important role in the pathogenesis of Alzheimer's disease and can be generated by reactive oxygen species catalyzed by Cu2+ ions. The observation of increased Aβ and dityrosine in CSF from AD patients suggests that this could be used as a potential biomarker of oxidative stress in AD.
Collapse
Affiliation(s)
- Youssra K Al-Hilaly
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
- College of Sciences, Chemistry department, Al-Mustansiriyah University, Baghdad, Iraq
| | | | | | - Lenzie Ford
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Eldhose Skaria
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Michael Cole
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | | | - Kyle L Morris
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
- Current address: School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK
| | - Alaa Abdul Sada
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Julian R Thorpe
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer BN1 9QG, UK
| |
Collapse
|
13
|
Li M, Xu C, Wu L, Ren J, Wang E, Qu X. Self-assembled peptide-polyoxometalate hybrid nanospheres: two in one enhances targeted inhibition of amyloid β-peptide aggregation associated with Alzheimer's disease. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:3455-3461. [PMID: 23650245 DOI: 10.1002/smll.201202612] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Indexed: 05/28/2023]
Abstract
Amyloid fibril formation is a critical step in Alzheimer's disease (AD) pathogenesis. Inhibition of Aβ aggregation has shown promising against AD and has been used in clinic trials. Here, a novel strategy is reported for the self-assembly of polyoxometalate-peptide (POM@P) hybrid particles as bifunctional Aβ inhibitors. The two-in-one bifunctional POM@P nanoparticles show an enhanced inhibition effect on amyloid aggregation in mice cerebrospinal fluid. Incorporating a clinically used Aβ fibril-staining dye, congo red (CR), into the hybrid colloidal spheres, the nanoparticles can also act as an effective fluorescent probe to monitor the inhibition process of POM@P via CR fluorescence change in real time. It is believed that such flexible organic-inorganic hybrid systems may prompt the design of new multifunctional materials for AD treatment.
Collapse
Affiliation(s)
- Meng Li
- Laboratory of Chemical Biology, Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth, Resource Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China, Fax: 86-431-85262625
| | | | | | | | | | | |
Collapse
|
14
|
Randall C, Mosconi L, de Leon M, Glodzik L. Cerebrospinal fluid biomarkers of Alzheimer's disease in healthy elderly. FRONT BIOSCI-LANDMRK 2013; 18:1150-73. [PMID: 23747874 PMCID: PMC3904672 DOI: 10.2741/4170] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Numerous studies have shown that Alzheimer's Disease (AD) pathology begins before the onset of clinical symptoms. Because therapies are likely to be more effective if they are implemented early in the disease progression, it is necessary to identify reliable biomarkers to detect AD pathology in the early stages of the disease, ideally in presymptomatic individuals. Recent research has identified three candidate cerebrospinal fluid (CSF) biomarkers that reflect AD pathology: amyloid beta, total tau protein (t-tau), and tau protein phosphorylated at AD-specific epitopes (p-tau). They are useful in supporting the AD diagnosis and have predictive value for AD when patients are in the stage of mild cognitive impairment (MCI). However, their predictive utility in cognitively healthy subjects is still being evaluated. We conducted a review of studies published between 1993 and 2011 and summarized their findings on the role of CSF biomarkers for AD in healthy elderly.
Collapse
Affiliation(s)
- Catherine Randall
- Center for Brain Health, 145 East 32nd Street, 5th floor. New York, NY 10016
| | - Lisa Mosconi
- Center for Brain Health, 145 East 32nd Street, 5th floor. New York, NY 10016
| | - Mony de Leon
- Center for Brain Health, 145 East 32nd Street, 5th floor. New York, NY 10016
| | - Lidia Glodzik
- Center for Brain Health, 145 East 32nd Street, 5th floor. New York, NY 10016
| |
Collapse
|
15
|
Hampel H, Blennow K. CSF tau and β-amyloid as biomarkers for mild cognitive impairment. DIALOGUES IN CLINICAL NEUROSCIENCE 2012. [PMID: 22034251 PMCID: PMC3181816 DOI: 10.31887/dcns.2004.6.4/hhampel] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Early diagnosis of Alzheimer s disease (AD) is relevant in order to initiate symptomatic treatment with antidementia drugs. This will be of greater significance if the drugs aimed at slowing down the degenerative process (secondary prevention) prove to affect AD pathology and are clinically effective, such as γ-secretase inhibitors. However, there is currently no clinical assessment to differentiate the patients with mild cognitive impairment (MCI) who will progress to AD from those with a benign form of memory impairment that is part of the normal aging process. Thus, there is great clinical need for diagnostic and predictive biomarkers, as well as biomarkers for classification purposes, to identify incipient AD in MCI subjects. The most promising cerebrospinal fluid (CSF) biomarker candidates are total tau protein (T-tau), phosphorylated tau protein (P-tau), and the 42-andno acid form offi-amyloid (Aβ42), which may, if used in the right clinical context, prove to have sufficient diagnostic accuracy and predictive power to resolve this diagnostic challenge.
Collapse
Affiliation(s)
- Harald Hampel
- Alzheimer Memorial Center and Geriatric Psychiatry Branch, Department of Psychiatry, Ludwig-Maximilian University, Munich, Germany (Harald Hampel); Department of Clinical Neuroscience, Section of Experimental Neuroscience, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden (Kaj Blennow)
| | | |
Collapse
|
16
|
Cullen VC, Fredenburg RA, Evans C, Conliffe PR, Solomon ME. Development and advanced validation of an optimized method for the quantitation of Aβ42 in human cerebrospinal fluid. AAPS JOURNAL 2012; 14:510-8. [PMID: 22552903 DOI: 10.1208/s12248-012-9360-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 04/05/2012] [Indexed: 11/30/2022]
Abstract
Cerebrospinal fluid (CSF) biomarkers have been extensively utilized in the diagnosis of Alzheimer's disease (AD) and characterization of progression. One important CSF biomarker is the amyloid beta 42 (Aβ(42)) peptide, a key player in AD pathogenesis. The INNOTEST® Aβ(42) ELISA kit has been widely used but an advanced level of method development and validation has not been reported. To support a clinical trial in AD, we successfully completed a Good Laboratory Practices (GLP)-level validation of the method to establish the parameters of precision, accuracy, parallelism, selectivity, specificity, and linearity of dilution of the assay in CSF matrix, as well as CSF storage stability. Several modifications were required to optimize the assay and ensure consistent results in a clinical-trial setting. These included the use of additional calibrators, an adjusted standard curve range, a minimum required dilution (MRD) of CSF by 6-fold to avoid matrix interference and mitigation of analyte adsorption to labware by the addition of Tween-20. The optimized method displayed a quantitative range of 375-4,500 pg/mL. The inter-assay precision was ≤12.1 % CV and the inter-assay relative accuracy was ≤10.9 % absolute bias, bringing the total error of the assay to ≤23 %. The intra-assay precision of the assay at the high validation standard and below was ≤5.5 % CV; this enables sensitive detection of biomarker changes across a therapeutic regime. The INNOTEST® Aβ(42) ELISA kit, modified as reported here, may be appropriate for many applications, including regulatory agency acceptable clinical diagnosis and pharmacodynamic assessment.
Collapse
|
17
|
CSF Biomarkers for Amyloid and Tau Pathology in Alzheimer's Disease. J Mol Neurosci 2011; 47:1-14. [DOI: 10.1007/s12031-011-9665-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 10/13/2011] [Indexed: 12/16/2022]
|
18
|
Choi J, Lee HW, Suk K. Increased plasma levels of lipocalin 2 in mild cognitive impairment. J Neurol Sci 2011; 305:28-33. [PMID: 21463871 DOI: 10.1016/j.jns.2011.03.023] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/24/2011] [Accepted: 03/10/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by an irreversible cognitive decline and neuronal loss associated with neurofibrillary tangles and senile plaques. Mild cognitive impairment (MCI) is a prodromal stage of AD and is associated with memory loss and a high risk of developing AD. Lipocalin 2 (LCN2) is an acute phase protein. Our previous studies have shown that exposure to inflammatory stimuli resulted in elevated LCN2 levels in brain microglia and astrocytes implicating LCN2 in brain inflammation. Therefore, we hypothesize that there may be a significant change in the plasma LCN2 levels in patients with MCI and AD when compared to healthy control subjects. METHODS Forty-one patients with MCI, 62 patients with AD and 38 healthy elderly control subjects were recruited for this study. They were given a comprehensive battery of neuropsychological tests including a mini-mental status examination (MMSE) and clinical dementia rating (CDR). A variety of clinical information was collected from the semi-structured questionnaire administered. The LCN2 levels were measured using a specific enzyme-linked immunosorbent assay in the plasma, which had been collected early in the morning after overnight fasting. RESULTS The LCN2 levels were significantly higher in MCI patients compared to the healthy control subjects and AD patients [control vs. MCI (p=0.005); MCI vs. AD (p=0.009)]. There was a significant negative correlation between the LCN2 levels and CDR scores (r=-0.245, p=0.014), and there was a positive correlation between the LCN2 levels and MMSE scores (r=0.317, p=0.001) among all of the MCI and AD patients. CONCLUSION MCI represents a prodromal stage of AD, and inflammation occurs as one of the earliest pathological events in AD. Thus, increased plasma LCN2 levels during MCI could be helpful in predicting the progression from MCI to AD.
Collapse
Affiliation(s)
- Jihye Choi
- Department of Pharmacology, Brain Science and Engineering Institute, CMRI, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | | | | |
Collapse
|
19
|
Williams JH, Wilcock GK, Seeburger J, Dallob A, Laterza O, Potter W, Smith AD. Non-linear relationships of cerebrospinal fluid biomarker levels with cognitive function: an observational study. ALZHEIMERS RESEARCH & THERAPY 2011; 3:5. [PMID: 21329517 PMCID: PMC3109414 DOI: 10.1186/alzrt64] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 01/11/2011] [Accepted: 02/17/2011] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Levels of cerebrospinal fluid (CSF) β-amyloid (Aβ) and Tau proteins change in Alzheimer's disease (AD). We tested if the relationships of these biomarkers with cognitive impairment are linear or non-linear. METHODS We assessed cognitive function and assayed CSF Aβ and Tau biomarkers in 95 non-demented volunteers and 97 AD patients. We then tested non-linearities in their inter-relations. RESULTS CSF biomarkers related to cognitive function in the non-demented range of cognition, but these relations were weak or absent in the patient range; Aβ1-40's relationship was biphasic. CONCLUSIONS Major biomarker changes precede clinical AD and index cognitive impairment in AD poorly, if at all.
Collapse
Affiliation(s)
- Jonathan H Williams
- OPTIMA, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, UK.
| | | | | | | | | | | | | |
Collapse
|
20
|
|
21
|
Mild cognitive impairment:. DEMENTIA 2010. [DOI: 10.1017/cbo9780511780615.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
22
|
Head E, Pop V, Sarsoza F, Kayed R, Beckett TL, Studzinski CM, Tomic JL, Glabe CG, Murphy MP. Amyloid-beta peptide and oligomers in the brain and cerebrospinal fluid of aged canines. J Alzheimers Dis 2010; 20:637-46. [PMID: 20164551 DOI: 10.3233/jad-2010-1397] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The study of Alzheimer's disease (AD) pathogenesis requires the use of animal models that develop some amount of amyloid pathology in the brain. Aged canines (beagles) naturally accumulate human-type amyloid-beta peptide (Abeta) and develop parallel declines in cognitive function. However, the type and quantity of biochemically extracted Abeta in brain and cerebrospinal fluid (CSF), its link to aging, and similarity to human aging has not been examined systematically. Thirty beagles, aged 4.5-15.7 years, were studied. Abeta40 and Abeta42 were measured in CSF by ELISA, and from SDS and formic acid extracted prefrontal cortex. A sample of the contralateral hemisphere, used to assess immunohistochemical amyloid load, was used for comparison. In the brain, increases in Abeta42 were detected at a younger age, prior to increases in Abeta40, and were correlated with an increased amyloid load. In the CSF, Abeta42 decreased with age while Abeta40 levels remained constant. The CSF Abeta42/40 ratio was also a good predictor of the amount of Abeta in the brain. The amount of soluble oligomers in CSF was inversely related to brain extractable Abeta, whereas oligomers in the brain were correlated with SDS soluble Abeta42. These findings indicate that the Abeta in the brain of the aged canine exhibits patterns that mirror Abeta deposited in the human brain. These parallels support the idea that the aged canine is a useful intermediate between transgenic mice and humans for studying the development of amyloid pathology and is a potentially useful model for the refinement of therapeutic interventions.
Collapse
Affiliation(s)
- Elizabeth Head
- Department of Molecular and Biomedical Pharmacology and the Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40536-0230, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Andreasson U, Portelius E, Andersson ME, Blennow K, Zetterberg H. Aspects of beta-amyloid as a biomarker for Alzheimer's disease. Biomark Med 2010; 1:59-78. [PMID: 20477461 DOI: 10.2217/17520363.1.1.59] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease is an age-related neurodegenerative disorder that results in progressive cognitive impairment and death. The accumulation of beta-amyloid (Abeta) in specific brain regions is believed by many to represent the earliest event in the pathogenesis of the disease. Here, we review the key aspects of Abeta as a biomarker for Alzheimer's disease, including the pathogenicity of Abeta, the possible biological functions of its precursor protein, the Abeta metabolism and homeostasis, the diagnostic performance of different Abeta assays in different settings and the potential usefulness of Abeta as a surrogate marker for treatment efficacy in clinical trials of novel Abeta-targeting drugs against Alzheimer's disease.
Collapse
Affiliation(s)
- Ulf Andreasson
- Sahlgrenska University Hospital/Mölndal, Clinical Neurochemistry Laboratory/Mölndal, S-431 80, Göteborg University, Mölndal, Sweden
| | | | | | | | | |
Collapse
|
24
|
An unbiased, staged, multicentre, validation strategy for Alzheimer's disease CSF tau levels. Exp Neurol 2010; 223:432-8. [DOI: 10.1016/j.expneurol.2009.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 11/08/2009] [Accepted: 11/18/2009] [Indexed: 11/18/2022]
|
25
|
Janus C, Welzl H. Mouse models of neurodegenerative diseases: criteria and general methodology. Methods Mol Biol 2010; 602:323-345. [PMID: 20012407 DOI: 10.1007/978-1-60761-058-8_19] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The major symptom of Alzheimer's disease is rapidly progressing dementia, coinciding with the formation of amyloid and tau deposits in the central nervous system, and neuronal death. At present familial cases of dementias provide the most promising foundation for modelling neurodegeneration. We describe the mnemonic and other major behavioral symptoms of tauopathies, briefly outline the genetics underlying familiar cases and discuss the arising implications for modelling the disease in mostly transgenic mouse lines. We then depict to what degree the most recent mouse models replicate pathological and cognitive characteristics observed in patients.There is no universally valid behavioral test battery to evaluate mouse models. The selection of individual tests depends on the behavioral and/or memory system in focus, the type of a model and how well it replicates the pathology of a disease and the amount of control over the genetic background of the mouse model. However it is possible to provide guidelines and criteria for modelling the neurodegeneration, setting up the experiments and choosing relevant tests. One should not adopt a "one (trans)gene, one disease" interpretation, but should try to understand how the mouse genome copes with the protein expression of the transgene in question. Further, it is not possible to recommend some mouse models over others since each model is valuable within its own constraints, and the way experiments are performed often reflects the idiosyncratic reality of specific laboratories. Our purpose is to improve bridging molecular and behavioural approaches in translational research.
Collapse
Affiliation(s)
- Christopher Janus
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL, USA
| | | |
Collapse
|
26
|
Scheurich A, Urban PP, Koch-Khoury N, Fellgiebel A. CSF phospho-tau is independent of age, cognitive status and gender of neurological patients. J Neurol 2009; 257:609-14. [DOI: 10.1007/s00415-009-5382-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 10/26/2009] [Accepted: 11/02/2009] [Indexed: 10/20/2022]
|
27
|
Diniz BSO, Pinto Júnior JA, Forlenza OV. Do CSF total tau, phosphorylated tau, and beta-amyloid 42 help to predict progression of mild cognitive impairment to Alzheimer's disease? A systematic review and meta-analysis of the literature. World J Biol Psychiatry 2009; 9:172-82. [PMID: 17886169 DOI: 10.1080/15622970701535502] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The search for biomarkers as a diagnostic aid to the identification of patients in pre-dementia stages is a fast growing research area. In view of the low specificity attained with the clinically based diagnostic criteria, including those for mild cognitive impairment (MCI), biomarker information will add precision to the incipient dementia diagnostic work-up, particularly Alzheimer's disease (AD). We present a systematic review of the literature and meta-analysis of the most relevant publications about the role of CSF biomarkers in the identification of patients with probable Alzheimer's disease at pre-dementia stages. A total of 16 studies were included in the systematic review, five of which were suitable for meta-analysis. We compared the standard mean differences (SMD) of beta-amyloid 42 (Abeta42), total tau (T-tau) and phosphorylated tau (P-tau) for 130, 169 and 123 patients with MCI who converted to AD (MCI-AD) and 142, 157 and 130 controls, respectively. We conclude that when a clinical diagnosis of MCI is made at baseline assessment, low CSF levels of Abeta42 (SMD: -1.57, CI 95% [-2.30 to -0.84], P < 0.001), along with high T-tau (SMD: 1.52, CI 95% [1.25 to 1.79], P < 0.001), and high P-tau (SMD: 1.75, CI 95% [0.99 to 2.51], P < 0.001), help to predict the conversion to Alzheimer's disease as compared to controls subjects.
Collapse
Affiliation(s)
- Breno S O Diniz
- Laboratory of Neuroscience-LIM 27, Department and Institute of Psychiatry, Faculty of Medicine, University of Sao Paulo, Sao Paulo, Brazil
| | | | | |
Collapse
|
28
|
Abstract
Alzheimer disease is the most common cause of dementia, yet its clinical diagnosis remains uncertain until an eventual postmortem histopathology examination. Currently, therapy for patients with Alzheimer disease only treats the symptoms; however, it is anticipated that new disease-modifying drugs will soon become available.Diagnostic tools for detecting Alzheimer disease at an incipient stage that can reliably differentiate the disease from other forms of dementia are of key importance for optimal treatment. Biomarkers have the potential to aid in a correct diagnosis, and great progress has been made in the discovery and development of potentially useful biomarkers in recent years. This includes single protein biomarkers in the cerebrospinal fluid, as well as multi-component biomarkers, and biomarkers based on gene expression. Novel biomarkers that use blood and urine, the more easily available clinical samples, are also being discovered and developed. The plethora of potential biomarkers currently being investigated may soon provide biomarkers that fulfill different functions, not only for diagnostic purposes but also for drug development and to follow disease progression.
Collapse
|
29
|
Tang BL, Kumar R. Biomarkers of Mild Cognitive Impairment and Alzheimer’s Disease. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2008. [DOI: 10.47102/annals-acadmedsg.v37n5p406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Alzheimer’s disease (AD) is currently diagnosed only via clinical assessments and confirmed by postmortem brain pathology. Biochemical and neuroimaging markers could facilitate diagnosis, predict AD progression from a pre-AD state of mild cognitive impairment (MCI), and be used to monitor efficacies of disease-modifying therapies. It is now clear that cerebrospinal fluid (CSF) levels of Aβ40, Aβ42, total tau and phosphorylated tau have diagnostic values in AD. Measurements of the above CSF markers in combination are useful in predicting the risk of progression from MCI to AD. Recent advances further support a notion that plasma Aβ levels, expressed as an Aβ42/Aβ40 ratio, could also be of value. New potential biomarkers are emerging, and CSF or plasma marker profiles may eventually become part of the clinician’s toolkit for accurate AD diagnosis and management. These biomarkers, along with clinical assessment, neuropsychological testing and neuroimaging could achieve a much higher diagnostic accuracy for AD and related disorders in the future.
Key words: Alzheimer’s disease, b-amyloid (Ab), Biomarkers, Mild cognitive impairment (MCI), Tau
Collapse
|
30
|
Kawasaki Y. [Advance prediction of Mild Cognitive Impairment (MCI) using (99m)Tc-ECD SPECT brain blood flow imaging]. Nihon Ronen Igakkai Zasshi 2008; 45:202-212. [PMID: 18441495 DOI: 10.3143/geriatrics.45.202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
AIM Mild Cognitive Impairment (MCI) is considered as a precursor state of Alzheimer disease (AD). SPECT brain blood flow imaging was investigated in MCI and it's relevance to the prognosis of MCI was evaluated in an attempt define the characteristics of brain blood flow imaging of MCI (amnestic MCI; aMCI) converting to AD. METHODS Ninety-two patients over 60 years old with amnesia were studied. (99m)Tc-ECD SPECT brain blood flow examinations of the subject under drug-free conditions were conducted and imaging was analyzed according to the first clinical diagnosis. Patients given a diagnosis of MCI on the first clinical diagnosis, were examined again after 2 years and the SPECT imaging before 2 years previously was classified and analyzed. RESULTS Of them, there were 35 MCI patients, converting of 13 AD patients (37.1%; aMCI), 10 MCI patients (28.6%; non-converter), 4 depression patients (11.4%; Depression type MCI (dMCI)), 1 Geriatric psychosis patient, but 7 patients dropped out. In the aMCI group, relative hypoperfusion was recognized in the posterior cingulate and the precuneus. In the dMCI group, relative hypoperfusion was recognized in the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate. In the non-converter group, relative hypoperfusion was recognized in the basal forebrain. CONCLUSIONS The hypoperfusion of the precuneus in aMCI, and the hypoperfusion of the right frontal lobe (DLPFC, dorsal-anterior cingulate) in dMCI were characteristic brain blood-flow abnormalities. We believe (99m)Tc-ECD SPECT brain blood flow imaging to be useful in the diagnosis of aMCI and in the early detection of depression.
Collapse
Affiliation(s)
- Yohsuke Kawasaki
- Department of Neuropsychiatry, Kyorin University, School of Medicine Department of Psychiatry, Kyosai Hospital
| |
Collapse
|
31
|
Höglund K, Hansson O, Buchhave P, Zetterberg H, Lewczuk P, Londos E, Blennow K, Minthon L, Wiltfang J. Prediction of Alzheimer's disease using a cerebrospinal fluid pattern of C-terminally truncated beta-amyloid peptides. NEURODEGENER DIS 2008; 5:268-76. [PMID: 18309230 DOI: 10.1159/000119457] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 06/19/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Identifying individuals at high risk of developing Alzheimer's disease (AD) is important for future therapeutic strategies, and there is a clinical need for diagnostic biomarkers to identify incipient AD. OBJECTIVE The aim of the present study was to investigate if the AD-associated Abeta peptide pattern recently found in cerebrospinal fluid (CSF) could discriminate between patients with incipient AD and those with stable mild cognitive impairment (MCI) by analyzing CSF from patients with MCI at baseline. METHODS The levels of Abeta(1-37, -38, -39, -40, -42) were analyzed by Abeta-SDS-PAGE/immunoblot in CSF from 19 healthy controls, 25 patients with stable MCI and from 25 patients with MCI who later developed AD during 4- to 6-year follow-up. RESULTS All healthy controls and 20 out of 22 patients who developed AD were correctly classified by their baseline Abeta peptide pattern. In 9 out of 25 stable MCI patients, the pattern indicated incipient AD in spite of clinical nonconversion. Interestingly, these individuals had apolipoprotein E genotypes and CSF levels of tau and phospho-tau that are known to be associated with high risk of AD. CONCLUSION Altogether, our study reveals the novel finding that the Abeta peptide pattern is able to predict AD in patients with MCI with a sensitivity of 91% and specificity of 64%. The specificity would increase to 94% if the high-risk patients in the stable MCI cohort developed AD during extended follow-up.
Collapse
Affiliation(s)
- K Höglund
- Neurochemistry Lab, Department of Neuroscience and Physiology, Göteborg University, Molndal, Sweden.
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Abstract
Mild cognitive impairment refers to the transitional period between normal cognition and dementia, but is not an extension of normal ageing. Subjects with mild cognitive impairment have subtle but measurable cognitive impairment that is not severe enough to interfere with independent living or fulfil diagnosis criteria of dementia.
Collapse
|
33
|
Zainaghi IA, Forlenza OV, Gattaz WF. Abnormal APP processing in platelets of patients with Alzheimer's disease: correlations with membrane fluidity and cognitive decline. Psychopharmacology (Berl) 2007; 192:547-53. [PMID: 17356877 DOI: 10.1007/s00213-007-0748-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Accepted: 02/13/2007] [Indexed: 12/15/2022]
Abstract
RATIONALE Previous studies have implicated platelet amyloid precursor protein (APP) as a candidate biomarker for Alzheimer's disease (AD). Platelets contain more than 95% of the circulating APP and enclose the enzymatic machinery for the APP metabolism yielding both soluble APP and amyloid-beta peptides. OBJECTIVES The objective of this study is to compare the ratio of 130- to 110-kDa fragments of APP in platelets from patients with AD, mild cognitive impairment (MCI), and elderly controls. MATERIALS AND METHODS After subjects were grouped according to diagnosis, APP ratio in platelets was evaluated by means of Western blot analysis. RESULTS The APP ratio was significantly lower in AD patients (1.01 +/- 0.21) as compared to controls (1.24 +/- 0.21, p = 0.001) and MCI patients (1.18 +/- 0.21, p = 0.027), but no significant differences were found between MCI and controls (p = 0.904). In addition, we found positive correlations between the APP ratio and 1,6-diphenyl-1,3,5-hexatriene anisotropy (r = 0.3, p = 0.01), as well as with certain parameters of cognitive decline, namely, the mini-mental state examination score (r = 0.33, p = 0.003), the total Cambridge cognitive test (CAMCOG) score (r = 0.37, p = 0.001), and the score on the memory subscale of the CAMCOG (r = 0.38, p = 0.001). CONCLUSIONS The pattern of platelet APP fragments was altered in patients with AD but not in patients with MCI. The alteration of APP fragments was correlated with membrane fluidity and the cognitive decline.
Collapse
Affiliation(s)
- Isis A Zainaghi
- Laboratory of Neuroscience LIM 27, Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | | | | |
Collapse
|
34
|
Tomita N, Ootsuki M, Maruyama M, Matsui T, Higuchi M, Tsutsui M, Seki T, Iwasaki K, Tamamizu M, Sozu T, Yoshimura I, Furukawa K, Arai H. Long-term cognitive benefits of donepezil in Alzheimer?s disease: A retrospective comparison between 1994?1999 and 2000?2004. Geriatr Gerontol Int 2007. [DOI: 10.1111/j.1447-0594.2007.00367.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
35
|
Montalto MC, Farrar G, Hehir CT. Fibrillar and Oligomeric beta-Amyloid as Distinct Local Biomarkers for Alzheimer's Disease. Ann N Y Acad Sci 2007; 1097:239-58. [PMID: 17413026 DOI: 10.1196/annals.1379.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Beta-amyloid is a key component of Alzheimer's disease (AD) pathology. Researchers in both academic and industry are actively pursuing the development of imaging tracers and techniques to noninvasively measure local levels of beta-amyloid in the Alzheimer's brain. This presentation summarizes recent data and discusses the opportunities and challenges of imaging plaques containing fibrillar beta-amyloid for the early diagnosis and therapeutic monitoring of amyloid targeted therapies. Further, the value and feasibility of measuring the recently described soluble oligomeric form of beta-amyloid as an alternative noninvasive biomarker is also discussed.
Collapse
Affiliation(s)
- Michael C Montalto
- Molecular Imaging and Diagnostics Advanced Technology Program, Biosciences, GE Global Research Center, Niskayuna, New York, USA.
| | | | | |
Collapse
|
36
|
Stefani A, Martorana A, Bernardini S, Panella M, Mercati F, Orlacchio A, Pierantozzi M. CSF markers in Alzheimer disease patients are not related to the different degree of cognitive impairment. J Neurol Sci 2006; 251:124-8. [PMID: 17097109 DOI: 10.1016/j.jns.2006.09.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 09/18/2006] [Accepted: 09/19/2006] [Indexed: 10/23/2022]
Abstract
Standard markers in cerebrospinal fluid (CSF), as soluble amyloid beta 1-42 (Abeta1-42) and total tau protein (t-tau), may contribute to dementia subtypes diagnostic accuracy. Yet, their sensitivity to assess the different degree of cognitive deficit is not fully clarified. Our study analyses Abeta1-42 and t-tau CSF levels in different cohorts of Alzheimer's disease (AD) patients, distinguished as early AD (mild cognitively impaired subjects recently converted to AD), mild AD (MMSE<23; > or =18), and moderately advanced AD (MMSE<18). The control group was represented by age-matched patients affected by depressive pseudo-dementia. Reduced Abeta1-42 and increased t-tau CSF levels were confirmed as hallmarks of AD at any disease stage. In early AD patients, Abeta1-42 levels were already significantly low, if compared to the control group (336 vs 867 ng/L; p<0.0001). On the contrary, Abeta1-42 levels did not differ between AD subgroups, and in particular between mild to moderate AD. A significant progressive increase of t-tau concentration was found when comparing early AD (269 ng/L) to more advanced AD stages (468 ng/L and 495 ng/L for mild and moderate AD, respectively). Our findings confirm that the impairment of amyloidogenic cascade is an early, even pre-clinical process, but suggest that soluble Abeta1-42 concentration has a negligible correlation with the clinical progression. Conversely, t-tau concentration correlates with the transition towards marked cognitive impairment.
Collapse
|
37
|
Abstract
As populations continue to age, the prevalence of dementia is expected to increase. AD is by far the most common cause of dementia. The clinical course of dementia represents the challenges that this disease presents. There are no truly effective therapies for treating dementia, and the cost effectiveness of ChEIs has been challenged; however, there has been an explosion of information about AD. Evidence-based practice parameters for diagnosis and management of dementia have been developed. There has been an increased interest in the possible prodromal states of dementia, such as MCI. The concept of MCI has risen in prominence in recent years; it is speculated that initiation of therapies early in the course of disease may be needed for them to be effective. Considering the enormous burdens that AD places on individuals and society, disease-modifying treatments for AD are needed desperately. There are promising avenues for the development of potentially disease-modifying therapies for this devastating disease.
Collapse
Affiliation(s)
- Seema Joshi
- Division of Geriatric Medicine, Saint Louis University School of Medicine, 1402 South Grand Boulevard, M238, MO 63104, USA
| | | |
Collapse
|
38
|
Nagao M, Sugawara Y, Ikeda M, Fukuhara R, Ishikawa T, Murase K, Kikuchi T, Mochizuki T, Miki H. Heterogeneity of posterior limbic perfusion in very early Alzheimer's disease. Neurosci Res 2006; 55:285-91. [PMID: 16644047 DOI: 10.1016/j.neures.2006.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 02/24/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE This study was designed to quantify the heterogeneity of cerebral perfusion on SPECT images in elderly controls and Alzheimer's disease (AD) patients in mild stage using a three-dimensional fractal analysis (3D-FA). MATERIAL AND METHOD Seventy-five patients with possible and probable AD based on the NINCDS/ADRDA criteria, and thirty-one elderly controls underwent 99mTc-HMPAO SPECT scanning. Dementia severity was assessed using the clinical dementia rating (CDR). Patients with CDR scores of 0.5 (n=33) were classified as "very early" and those with CDR 1 (n=42) as "early". We delineated the SPECT images using 2 cutoffs (35% and 50% cutoffs of the maximal voxel radioactivity) and measured the number of voxels in the areas included by the contours obtained with each cutoff level. The fractal dimension (FD) was calculated by relating the logarithms of cutoff level and the number of voxels. Posterior limbic images were reconstructed at 30 degrees positive to the coronal plane, and posterior limbic FD was calculated. RESULT Posterior limbic FD for early AD, very early AD, and control groups were 1.03+/-0.16, 1.02+/-0.17, and 0.87+/-0.14 (P=0.001 versus early AD group, P=0.001 versus very early AD). Use of the posterior limbic FD and the ratio of posterior limbic FD to total FD separated very early AD patients from controls with a sensitivity of 76% and a specificity of 81%. CONCLUSION 3D-FA indicated significant differences in the heterogeneity of CBF distribution between patients with AD in mild stage and elderly controls. Posterior limbic FD may be useful for easily and objectively distinguishing patients with very early AD from aging people.
Collapse
Affiliation(s)
- Michinobu Nagao
- Department of Radiology, Ehime University Medical School, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Borroni B, Di Luca M, Padovani A. Predicting Alzheimer dementia in mild cognitive impairment patients. Are biomarkers useful? Eur J Pharmacol 2006; 545:73-80. [PMID: 16831417 DOI: 10.1016/j.ejphar.2006.06.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 03/19/2006] [Accepted: 06/13/2006] [Indexed: 11/22/2022]
Abstract
A correct clinical diagnosis in the early stage of Alzheimer disease is not only of importance given the current available treatment with acetylcholine esterase inhibitors, but would be the basis for disease-modifying therapy slowing down or arresting the degenerative process. Moreover, in the last years, several efforts have been made to determine if a patient with mild cognitive impairment has incipient Alzheimer disease, i.e. will progress to Alzheimer disease with dementia, or have a benign form of mild cognitive impairment. In this review, the recent published reports regarding progress in early and preclinical Alzheimer disease diagnosis are discussed and the role of peripheral and cerebrospinal fluid biomarkers highlighted. Approaches combining panels of different biomarkers show promise for discovering profiles that are characteristic of Alzheimer disease, even in the pre-symptomatic stage. More work is needed but available novel perspectives offered by recent introduced technologies shed some lights in identifying incipient Alzheimer disease in mild cognitive impairment subjects.
Collapse
Affiliation(s)
- Barbara Borroni
- Department of Medical Sciences, University of Brescia, Italy.
| | | | | |
Collapse
|
40
|
Matsui T, Nemoto M, Maruyama M, Yuzuriha T, Yao H, Tanji H, Ootsuki M, Tomita N, Matsushita S, Higuchi S, Yoshida YI, Seki T, Iwasaki K, Furukawa K, Arai H. Plasma Homocysteine and Risk of Coexisting Silent Brain Infarction in Alzheimer’s Disease. NEURODEGENER DIS 2006; 2:299-304. [PMID: 16909012 DOI: 10.1159/000092316] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Accepted: 01/23/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cerebrovascular disease is common in Alzheimer's disease (AD). Elevated plasma homocysteine (pHcy) levels are reported to be associated with an increased risk of poor cognition and dementia. OBJECTIVE To determine whether high pHcy levels are associated with an increased risk of coexisting silent brain infarctions (SBIs) in AD. METHODS Study population comprising 143 outpatients with clinical diagnosis of probable AD (73.3 +/- 7.0 years) were classified into 2 groups according to the presence or absence of SBIs on magnetic resonance imaging. RESULTS SBIs were noted in 32.9% (47/143) of the AD patients. The pHcy levels in the AD with SBIs (14.0 +/- 4.5 micromol/l) were significant ly elevated compared with the AD without SBIs (11.7 +/- 4.7 micromol/l, p = 0.007). After adjusting for age and gender, high pHcy (>12.4 micromol/l), but not hypertension, was associated with an increased risk of developing SBIs in AD (OR = 4.61, 95% CI = 1.74-12.2, p = 0.002). However, age at onset, cognitive function, cerebrospinal tau or amyloid beta-peptide(1-42) levels were not significantly correlated with pHcy levels in AD. CONCLUSION SBIs commonly coexist with AD, and may be a unique vascular condition in which homocysteine plays an important role. Homocysteine-lowering therapy rather than antihypertensive medication might be an appropriate strategy to prevent stroke associated with AD.
Collapse
Affiliation(s)
- Toshifumi Matsui
- Department of Geriatric and Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Brys M, Mosconi L, De Santi S, Rich K, de Leon MJ. Cerebrospinal fluid biomarkers for mild cognitive impairment. ACTA ACUST UNITED AC 2006. [DOI: 10.2217/1745509x.2.1.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article discusses the current knowledge on the most promising cerebrospinal fluid diagnostic biomarkers for mild cognitive impairment and early Alzheimer’s disease. The considered biomarkers include total and phosphorylated Tau proteins, 40- and 42-residue forms of amyloid β and isoprostanes. Both the biological rationales and validation histories for each of the cerebrospinal fluid biomarkers are briefly presented and clinical results from relevant studies in the field are discussed. Comments on issues related to the cerebrospinal fluid clearance kinetics and how this may affect detection of the biomarkers in the cerebrospinal fluid are also presented. The concept of mild cognitive impairment and current views on this potential stage of the transition from normal aging to Alzheimer’s disease and to other dementias are also discussed. Future perspectives, including limitations in identifying reliable, sensitive and specific mild cognitive impairment/Alzheimer’s disease biomarkers, are presented.
Collapse
Affiliation(s)
- Miroslaw Brys
- Center for Brain Health, New York University School of Medicine, 560 First Avenue MHL 400, New York, NY 10016, USA
| | - Lisa Mosconi
- Center for Brain Health, New York University School of Medicine, 560 First Avenue MHL 400, New York, NY 10016, USA
| | - Susan De Santi
- Center for Brain Health, New York University School of Medicine, 560 First Avenue MHL 400, New York, NY 10016, USA
| | - Kenneth Rich
- Center for Brain Health, New York University School of Medicine, 560 First Avenue MHL 400, New York, NY 10016, USA
| | - Mony J de Leon
- Center for Brain Health, New York University School of Medicine, 560 First Avenue MHL 400, New York, NY 10016, USA
| |
Collapse
|
42
|
Formichi P, Battisti C, Radi E, Federico A. Cerebrospinal fluid tau, Aß, and phosphorylated tau protein for the diagnosis of Alzheimer's disease. J Cell Physiol 2006; 208:39-46. [PMID: 16447254 DOI: 10.1002/jcp.20602] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The diagnosis of AD is still largely based on exclusion criteria of secondary causes and other forms of dementia with similar clinical pictures, than the diagnostic accuracy of AD is low. Improved methods of early diagnosis are needed, particularly because drugs treatment is more effective in the early stages of the disease. Recent research focused the attention to biochemical diagnostic markers (biomarkers) and according to the proposal of a consensus group on biomarkers, three candidate CSF markers reflecting the pathological AD processes, have recently been identified: total tau protein (t-tau), amyloid beta(1-42) protein (A beta42), and tau protein phosphorylated at AD-specific epitopes (p-tau). Several articles report reduced CSF levels of A beta42 and increased CSF levels of t-tau and p-tau in AD; the sensitivity and specificity of these data are able for discrimination of AD patients from controls. However, the specificity for other dementias is low. According to the literature analysis reported in the present review, we can conclude that the combination of the CSF markers and their ratios may significantly increase the specificity and the accuracy of AD diagnosis.
Collapse
Affiliation(s)
- Patrizia Formichi
- Department of Neurological and Behavioural Sciences, University of Siena, Siena, Italy
| | | | | | | |
Collapse
|
43
|
Inoue K, Garner C, Ackermann BL, Oe T, Blair IA. Liquid chromatography/tandem mass spectrometry characterization of oxidized amyloid beta peptides as potential biomarkers of Alzheimer's disease. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:911-8. [PMID: 16470704 DOI: 10.1002/rcm.2395] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Alzheimer's disease is characterized by the deposition of senile plaques that consist primarily of amyloid beta peptides. There is substantial evidence that amyloid beta is oxidized in vivo, which has led to the suggestion that oxidative stress is an important mediator of Alzheimer's disease. Metal-catalyzed oxidation can mimic in vivo oxidation of amyloid beta because the metal ion binds to the amino acid residues at the site of oxidation, which then deliver reactive oxygen species to that site. Based on electrospray mass spectrometry, it has been suggested that metal-catalyzed oxidation occurs on histidines-13 and -14. Unfortunately, the amyloid beta peptides provide complex spectra, so it is difficult to definitively characterize the sites of oxidation. Trypsin digestion of both native and oxidized amyloid beta1-16 and amyloid beta1-40 resulted in the formation of tryptic peptides corresponding to amyloid beta6-16, which could be separated by liquid chromatography (LC). Sites of oxidation were then unequivocally characterized as histidine-13 and histidine-14 by LC/tandem mass spectrometric (MS/MS) analysis of the tryptic peptides. The ability to analyze the specific amyloid beta6-16 tryptic fragments derived from full-length amyloid beta peptides will make it possible to determine whether oxidation in vivo occurs at specific histidine residues and/or at other amino acid residues such as methionine-35. Using methodology based on LC/MS/MS it will also be possible to analyze the relative amounts of oxidized peptides and native peptide in cerebrospinal fluid from patients with Alzheimer's disease as biomarkers of oxidative stress.
Collapse
Affiliation(s)
- Koichi Inoue
- Center for Cancer Pharmacology, University of Pennsylvania School of Medicine, 854 BRB II/III, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA
| | | | | | | | | |
Collapse
|
44
|
Maruyama M, Ishizawa K, Tomita N, Nemoto M, Yasuda H, Ebihara S, Ohrui T, Seki T, Iwasaki K, Okamura N, Higuchi M, Yoshida H, Kudo Y, Arai H, Sasaki H. Lithium therapy and cerebrospinal fluid biomarker levels in Alzheimer's disease. Geriatr Gerontol Int 2005. [DOI: 10.1111/j.1447-0594.2005.00302.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
45
|
Abstract
The introduction of acetylcholine esterase (AChE) inhibitors as a symptomatic treatment of Alzheimer's disease (AD) has made patients seek medical advice at an earlier stage of the disease. This has highlighted the importance of diagnostic markers for early AD. However, there is no clinical method to determine which of the patients with mild cognitive impairment (MCI) will progress to AD with dementia, and which have a benign form of MCI without progression. In this paper, the performance of cerebrospinal fluid (CSF) protein biomarkers for AD is reviewed. The diagnostic performance of the three biomarkers, total tau, phospho-tau, and the 42 amino acid form of beta-amyloid have been evaluated in numerous studies and their ability to identify incipient AD in MCI cases has also been studied. Some candidate AD biomarkers including ubiquitin, neurofilament proteins, growth-associated protein 43 (neuromodulin), and neuronal thread protein (AD7c) show interesting results but have been less extensively studied. It is concluded that CSF biomarkers may have clinical utility in the differentiation between AD and several important differential diagnoses, including normal aging, depression, alcohol dementia, and Parkinson's disease, and also in the identification of Creutzfeldt-Jakob disease in cases with rapidly progressive dementia. Early diagnosis of AD is not only of importance to be able to initiate symptomatic treatment with AChE inhibitors, but will be the basis for initiation of treatment with drugs aimed at slowing down or arresting the degenerative process, such as gamma-secretase inhibitors, if these prove to affect AD pathology and to have a clinical effect.
Collapse
Affiliation(s)
- Kaj Blennow
- Department of Clinical Neuroscience, Section of Experimental Neuroscience, The Sahlgrenska Academy at Göteborg University, SE-43180 Göteborg, Sweden.
| |
Collapse
|
46
|
Padovani A, Borroni B, Di Luca M. Advances on biological markers in early diagnosis of Alzheimer disease. Adv Clin Chem 2005; 39:107-29. [PMID: 16013669 DOI: 10.1016/s0065-2423(04)39004-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Alessandro Padovani
- Department of Neurological Sciences, University of Brescia, 25100 Brescia, Italy
| | | | | |
Collapse
|
47
|
Andreasen N, Blennow K. CSF biomarkers for mild cognitive impairment and early Alzheimer's disease. Clin Neurol Neurosurg 2005; 107:165-73. [PMID: 15823670 DOI: 10.1016/j.clineuro.2004.10.011] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 09/01/2004] [Accepted: 10/12/2004] [Indexed: 11/28/2022]
Abstract
A correct clinical diagnosis, early in the course of Alzheimer's disease (AD), is of importance given the currently available symptomatic treatment with acetylcholine esterase inhibitors. The development of disease-modifying drugs like beta-sheet breakers or gamma- and beta-secretase inhibitors, emphasizes the need of improved diagnostic accuracy, especially in patients with mild cognitive impairment (MCI) that have incipient AD. Therefore, diagnostic markers in the cerebrospinal fluid (CSF) have become a rapidly growing research field. Three cerebrospinal fluid biomarkers (the 42 amino acid form of beta-amyloid (A beta), total tau, and phospho tau) have been evaluated in numerous scientific papers. These CSF markers have high sensitivity to differentiate early and incipient AD from normal aging, depression, alcohol dementia and Parkinson's disease, but lower specificity against other dementias, such as frontotemporal and Lewy body dementia. If these biomarkers are used in combination with a careful medical history, clinical examination, standard laboratory tests and imaging techniques of the brain, the diagnostic accuracy may be appropriate for the clinical evaluation of MCI cases.
Collapse
Affiliation(s)
- Niels Andreasen
- Karolinska Institutet, Department of NEUROTEC, Section of Geriatric Medicine, M51, Karolinska University Hospital, Huddinge, SE-141 86 Stockholm, Sweden.
| | | |
Collapse
|
48
|
|
49
|
Best JD, Jay MT, Otu F, Ma J, Nadin A, Ellis S, Lewis HD, Pattison C, Reilly M, Harrison T, Shearman MS, Williamson TL, Atack JR. Quantitative measurement of changes in amyloid-beta(40) in the rat brain and cerebrospinal fluid following treatment with the gamma-secretase inhibitor LY-411575 [N2-[(2S)-2-(3,5-difluorophenyl)-2-hydroxyethanoyl]-N1-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl]-L-alaninamide]. J Pharmacol Exp Ther 2005; 313:902-8. [PMID: 15743924 DOI: 10.1124/jpet.104.081174] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The efficacy of gamma-secretase inhibitors in vivo has, to date, been generally assessed in transgenic mouse models expressing increased levels of amyloid-beta (Abeta) peptide thereby allowing the detection of changes in Abeta production. However, it is not clear whether the in vivo potency of gamma-secretase inhibitors is independent of the level of amyloid precursor protein expression. In other words, does a gamma-secretase inhibitor have the same effect in nontransgenic physiological animals versus transgenic overexpressing animals? In the present study, an immunoassay has been developed which can detect Abeta(40) in the rat brain, where concentrations are much lower than those seen in transgenic mice such as Tg2576 (c. 0.7 and 25 nM, respectively) and in cerebrospinal fluid (CSF, c. 0.3 nM). Using this immunoassay, the effects of the gamma-secretase inhibitor LY-411575 [N(2)-[(2S)-2-(3,5-difluorophenyl)-2-hydroxyethanoyl]-N(1)-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl]-L-alaninamide] were assessed and robust dose-dependent reductions in rat brain and CSF Abeta(40) levels were observed with ID(50) values of 1.3 mg/kg for both brain and CSF. These values were comparable with those calculated for LY-411575 in transgenic mice. Time course experiments using LY-411575 demonstrated comparable temporal reductions in rat brain and CSF Abeta(40), further suggesting these two pools of Abeta are related. Accordingly, when all the data for the dose-response curve and time course were correlated, a strong association was observed between the brain and CSF Abeta(40) levels. These data demonstrate the utility of the rat as a novel approach for assessing the effects of gamma-secretase inhibitors on central nervous system Abeta(40) levels in vivo.
Collapse
Affiliation(s)
- Jonathan D Best
- Department of In Vivo Neuroscience, The Neuroscience Research Centre, Merck Sharp and Dohme Research Laboratories, Essex, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Ivanoiu A, Sindic CJM. Cerebrospinal fluid TAU protein and amyloid beta42 in mild cognitive impairment: prediction of progression to Alzheimer's disease and correlation with the neuropsychological examination. Neurocase 2005; 11:32-9. [PMID: 15804922 DOI: 10.1080/13554790490896901] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cerebrospinal fluid (CSF) TAU protein and Amyloid beta42 were able to distinguish between 28 mild cognitive impairment (MCI) patients and both 38 normal aged and 17 anxious and depressed elderly patients, with good sensitivity/specificity when the two measures were combined. These biological markers are independent predictors of the presence of Alzheimer disease (AD), in addition to memory performance. Low Amyloid beta42 level was predictor of a fast progression of MCI patients to full blown dementia. The TAU protein level tended to correlate with memory performance, presumably in relation with the extent of the bilateral medio-temporal damage in early AD.
Collapse
Affiliation(s)
- Adrian Ivanoiu
- The Neurology Department Memory Clinic and Neurochemistry Laboratory, Saint Luc University Hospital, Catholic University of Louvain, Brussels, Belgium.
| | | |
Collapse
|