Medicine and Health Sciences Commons^™

A Multinational Study Distinguishing Alzheimer's And Healthy Patients Using Cerebrospinal Fluid Tau/Aβ42 Cutoff With Concordance To Amyloid Positron Emission Tomography Imaging, Yi Mo, Julie Stromswold, Kimberley Wilson, Daniel Holder, Cyrille Sur, Omar Laterza, Mary J. Savage, Arie Struyk, Phillip Scheltens, Charlotte E. Teunissen, James Burke, S. Lance Macaulay, Geir Brathen, Sigrid Botne Sando, Linda R. White, Christy Weiss, Arturo Cowes, Michele M. Bush, Ganga Desilva, David G. Darby, Stephanie Rainey-Smith, Jackie Surls, Eileen Sagini, Michael Tanen, Amy Altman, Johan Luthman, Michael F. Egan

Research outputs 2014 to 2021

Introduction

Changes in cerebrospinal fluid (CSF) tau and amyloid β (Aβ)42 accompany development of Alzheimer's brain pathology. Robust tau and Aβ42 immunoassays were developed to establish a tau/Aβ42 cutoff distinguishing mild-to-moderate Alzheimer's disease (AD) subjects from healthy elderly control (HC) subjects.

Methods

A CSF tau/Aβ42 cutoff criteria was chosen, which distinguished the groups and maximized concordance with amyloid PET. Performance was assessed using an independent validation cohort.

Results

A tau/Aβ42 = 0.215 cutoff provided 94.8% sensitivity and 77.7% specificity. Concordance with PET visual reads was estimated at 86.9% in a ∼50% PET positive population. In the validation cohort, the cutoff …

Finding Chemopreventatives To Reduce Amyloid Beta In Yeast, Ian Macreadie, Costa Arvanitis, Prashant Bharadwaj

Research outputs 2014 to 2021

Alzheimer's disease (AD) is the most common form of age-related dementia with the latest report (WorldAlzheimerReport, 2015) showing 46.8 million people are currently affected by dementia. That number is expected to double every 20 years unless there is effective therapeutic intervention.

Comparing Biological Markers Of Alzheimer's Disease Across Blood Fraction And Platforms: Comparing Apples To Oranges, Sid E. O'Bryant, Simone Lista, Robert A. Rissman, Melissa Edwards, Fan Zhang, James Hall, Herik Zetterberg, Simon Lovestone, Veer Bular Gupta, Neill Graff-Radford, Ralph N. Martins, Andreas Jeromin, Stephen Waring, Esther Oh, Mitchel Kling, Laura D. Baker, Harald Hampel

Research outputs 2014 to 2021

Introduction:

This study investigated the comparability of potential Alzheimer's disease (AD) biomarkers across blood fractions and assay platforms.

Methods:

Nonfasting serum and plasma samples from 300 participants (150 AD patients and 150 controls) were analyzed. Proteomic markers were obtained via electrochemiluminescence or Luminex technology. Comparisons were conducted via Pearson correlations. The relative importance of proteins within an AD diagnostic profile was examined using random forest importance plots.

Results:

On the Meso Scale Discovery multiplex platform, 10 of the 21 markers shared > 50% of the variance across blood fractions (serum amyloid A R2 = 0.99, interleukin (IL)10 R2 = 0.95, fatty …

The Effects Of Latrepirdine On Amyloid-Β Aggregation And Toxicity, Tenielle Porter, Prashant Bharadwaj, David Groth, Adrian Paxman, Simon Laws, Ralph Martins, Guiseppe Verdile

Research outputs 2014 to 2021

Latrepirdine (DimebonTM) has been demonstrated to be a neuroprotective and cognition improving agent in neurodegenerative diseases that feature protein aggregation and deposition, such as Alzheimer's disease (AD). The accumulation of amyloid-β (Aβ) protein aggregates is a key event in the neurodegenerative process in AD. This study explores if latrepirdine modulation of protein aggregation contributes to its neuroprotective mechanism of action. Assessment of neuronal cell death showed that there was a significant reduction in lactate dehydrogenase release at an equimolar ratio of Aβ:latrepirdine and with lower concentrations of latrepirdine. The ability of latrepirdine to alter the formation of Aβ42 aggregates was …

Biomarkers Of Alzheimer's Disease Risk In Peripheral Tissues; Focus On Buccal Cells, Maxime François, Wayne Leifert, Ralph Martins, Philip Thomas, Michael Fenech

Research outputs 2014 to 2021

Alzheimer's disease (AD) is a progressive degenerative disorder of the brain and is the most common form of dementia. To-date no simple, inexpensive and minimally invasive procedure is available to confirm with certainty the early diagnosis of AD prior to the manifestations of symptoms characteristic of the disease. Therefore, if population screening of individuals is to be performed, more suitable, easily accessible tissues would need to be used for a diagnostic test that would identify those who exhibit cellular pathology indicative of mild cognitive impairment (MCI) and AD risk so that they can be prioritized for primary prevention. This need …

Altered Cytological Parameters In Buccal Cells From Individuals With Mild Cognitive Impairment And Alzheimer's Disease, Maxime François, Wayne Leifert, Jane Hecker, Jeffrey Faunt, Ralph Martins, Philip Thomas, Michael Fenech

Research outputs 2014 to 2021

Previous studies have shown that mild cognitive impairment (MCI) may be reflective of the early stages of more pronounced neurodegenerative disorders such as Alzheimer's disease (AD). There is a need for a minimally invasive and inexpensive diagnostic to identify those who exhibit cellular pathology indicative of MCI and AD risk so that they can be prioritized for primary preventative measures. The hypothesis was that a minimally invasive approach using cytological markers in isolated buccal mucosa cells can be used to identify individuals of both MCI and AD. An automated buccal cell assay was developed using laser scanning cytometry (LSC) to …

A Surface Based Approach For Cortical Thickness Comparison Between Pib+ And Pib-Healthy Control Subjects, V Dore, P Bourgeat, J Fripp, O Acosta, G Chetelat, C Szoeke, Kathryn Ellis, Ralph Martins, V Villemagne, C L Masters, D Ames, C 0 Rowe, O Salvado

Research outputs 2012

β-amyloid has been shown to play a crucial role in Alzheimer's disease (AD). In vivo β-amyloid imaging using [11C] Pittsburgh compound B (PiB) positron emission tomography has made it possible to analyze the relationship between β-amyloid deposition and different pathological markers involved in AD. PiB allows us to stratify the population between subjects which are likely to have prodromal AD, and those who don't. The comparison of the cortical thickness in these different groups is important to better understanding and detect the first symptoms of the disease which may lead to an earlier therapeutic care to reduce neurone loss. Several …

Multiple Γ-Secretase Product Peptides Are Coordinately Increased In Concentration In The Cerebrospinal Fluid Of A Subpopulation Of Sporadic Alzheimer's Disease Subjects, Saori Hata, Miyako Taniguchi, Yi Piao, Takeshi Ikeuchi, Anne Fagan, David Holtzman, Randall Bateman, Hamid Sohrabi, Ralph Martins, Sam Gandy, Katsuya Urakami, Toshiharu Suzuki

Research outputs 2012

Background: Alcadeinα (Alcα) is a neuronal membrane protein that colocalizes with the Alzheimer's amyloid-β precursor protein (APP). Successive cleavage of APP by β- and γ-secretases generates the aggregatable amyloid-β peptide (Aβ), while cleavage of APP or Alcα by α- and γ-secretases generates non-aggregatable p3 or p3-Alcα peptides. Aβ and p3-Alcα can be recovered from human cerebrospinal fluid (CSF). We have previously reported alternative processing of APP and Alcα in the CSF of some patients with sporadic mild cognitive impairment (MCI) and AD (SAD). Results: Using the sandwich enzyme-linked immunosorbent assay (ELISA) system that detects total p3-Alcα, we determined levels of …

Intense Physical Activity Is Associated With Cognitive Performance In The Elderly, Belinda Brown, Jeremiah Peiffer, Hamid Sohrabi, Alinda Mondal, Veer Bala Gupta, Stephanie Rainey-Smith, Kevin Taddei, S Burnham, K Ellis, C Szoeke, C L Masters, D Ames, C Rowe, Ralph Martins

Research outputs 2012

Numerous studies have reported positive impacts of physical activity on cognitive function. However, the majority of these studies have utilised physical activity questionnaires or surveys, thus results may have been influenced by reporting biases. Through the objective measurement of routine levels of physical activity via actigraphy, we report a significant association between intensity, but not volume, of physical activity and cognitive functioning. A cohort of 217 participants (aged 60-89 years) wore an actigraphy unit for 7 consecutive days and underwent comprehensive neuropsychological assessment. The cohort was stratified into tertiles based on physical activity intensity. Compared with individuals in the lowest …

The Australian Imaging, Biomarkers And Lifestyle (Aibl) Study Of Aging: Methodology And Baseline Characteristics Of 1112 Individuals Recruited For A Longitudinal Study Of Alzheimer's Disease, Kathryn Ellis, Ashley Bush, David Darby, Daniel De Fazio, Jonathan Foster, Peter Hudson, Nicola Lautenschlager, Nat Lenzo, Ralph Martins, Paul Maruff, Colin Masters, Andrew Milner, Kevin Pike, Christopher Rowe, Greg Savage, Cassandra Szoeke, Kevin Taddei, Victor Villemagne, Michael Woodward, David Ames

Research outputs pre 2011

Background: The Australian Imaging, Biomarkers and Lifestyle (AIBL) flagship study of aging aimed to recruit 1000 individuals aged over 60 to assist with prospective research into Alzheimer's disease (AD). This paper describes the recruitment of the cohort and gives information about the study methodology, baseline demography, diagnoses, medical comorbidities, medication use, and cognitive function of the participants. Methods: Volunteers underwent a screening interview, had comprehensive cognitive testing, gave 80 ml of blood, and completed health and lifestyle questionnaires. One quarter of the sample also underwent amyloid PET brain imaging with Pittsburgh compound B (PiB PET) and MRI brain imaging, and …