Medicine and Health Sciences Commons^™

Alzheimer’S Disease Genetic Risk And Cognitive Reserve In Relationship To Long-Term Cognitive Trajectories Among Cognitively Normal Individuals, Corinne Pettigrew, Jurijs Nazarovs, Anja Soldan, Vikas Singh, Jiangxia Wang, Timothy Hohman, Logan Dumitrescu, Julia Libby, Brian Kunkle, Alden L. Gross, Sterling Johnson, Qiongshi Lu, Corinne Engelman, Colin L. Masters, Paul Maruff, Simon M. Laws, John C. Morris, Jason Hassenstab, Carlos Cruchaga, Susan M. Resnick, Melissa H. Kitner-Triolo, Yang An, Marilyn Albert

Research outputs 2022 to 2026

Background:

Both Alzheimer’s disease (AD) genetic risk factors and indices of cognitive reserve (CR) influence risk of cognitive decline, but it remains unclear whether they interact. This study examined whether a CR index score modifies the relationship between AD genetic risk factors and long-term cognitive trajectories in a large sample of individuals with normal cognition.

Methods:

Analyses used data from the Preclinical AD Consortium, including harmonized data from 5 longitudinal cohort studies. Participants were cognitively normal at baseline (M baseline age = 64 years, 59% female) and underwent 10 years of follow-up, on average. AD genetic risk was measured by …

Plasma Glial Fibrillary Acidic Protein In Autosomal Dominant Alzheimer's Disease: Associations With Aβ-Pet, Neurodegeneration, And Cognition, Pratishtha Chatterjee, Lisa Vermunt, Brian A. Gordon, Steve Pedrini, Lynn Boonkamp, Nicola J. Armstrong, Chengjie Xiong, Abhay K. Singh, Yan Li, Hamid R. Sohrabi, Kevin Taddei, Mark Molloy, Tammie L. S. Benzinger, John C. Morris, Celeste Karch, Sarah Berman, Jasmeer Chhatwal, Carlos Cruchaga, Neill R. Graff-Radford, Gregory S. Day, Martin Farlow, Nick Fox, Alison Goate, Jason Hassenstab, Jae-Hong Lee, Johannes Levin, Eric Mcdade, Hiroshi Mori, Richard Perrin, Raquel Sanchez-Valle, Peter R. Schofield, Allan Levey, Mathias Jucker, Colin L. Masters, Anne M. Fagan, Randall J. Bateman, Ralph N. Martins, Charlotte Teunissen, Dominantly Inherited Alzheimer Network

Research outputs 2022 to 2026

Background: Glial fibrillary acidic protein (GFAP) is a promising candidate blood-based biomarker for Alzheimer's disease (AD) diagnosis and prognostication. The timing of its disease-associated changes, its clinical correlates, and biofluid-type dependency will influence its clinical utility. Methods: We evaluated plasma, serum, and cerebrospinal fluid (CSF) GFAP in families with autosomal dominant AD (ADAD), leveraging the predictable age at symptom onset to determine changes by stage of disease. Results: Plasma GFAP elevations appear a decade before expected symptom onset, after amyloid beta (A ) accumulation and prior to neurodegeneration and cognitive decline. Plasma GFAP distinguished A -positive from A -negative ADAD …

First Presentation With Neuropsychiatric Symptoms In Autosomal Dominant Alzheimer's Disease: The Dominantly Inherited Alzheimer's Network Study, Antoinette O'Connor, Helen Rice, Josephine Barnes, Natalie S. Ryan, Kathy Y. Liu, Ricardo Francisco Allegri, Sarah Berman, John M. Ringman, Carlos Cruchaga, Martin R. Farlow, Jason Hassenstab, Jae-Hong Lee, Richard J. Perrin, Chengjie Xiong, Brian Gordon, Allan I. Levey, Alison Goate, Neil Graff-Radford, Johannes Levin, Mathias Jucker, Tammie Benzinger, Eric Mcdade, Hiroshi Mori, James M. Noble, Peter R. Schofield, Ralph N. Martins, Stephen Salloway, Jasmeer Chhatwal, John C. Morris, Randall Bateman, Rob Howard, Suzanne Reeves, Nick C. Fox

Research outputs 2022 to 2026

Behavioural changes and neuropsychiatric symptoms (NPS) commonly occur in Alzheimer’s disease (AD) but may not be recognised as AD-related when they are the presenting feature. NPS are important as they are associated with greater functional impairment, poorer quality of life, accelerated cognitive decline and worsened caregiver burden.1 Autosomal dominant AD (ADAD), although < 1% of total AD cases, provides a valuable opportunity to study the clinical heterogeneity of AD. The young age at onset reduces the prevalence of age-related comorbid pathologies and the near 100% penetrance of pathogenic mutations reduces the likelihood of misdiagnosis.2 Anxiety and depression commonly occur in ADAD family members, with increased levels of depression having been found among predementia female mutation carriers.3 Subsequent studies, however, have shown that anxiety and/or depression are common regardless of mutation status, occurring in almost one in three at-risk individuals, with one study reporting a higher rate of depression in non-carriers (17%) than asymptomatic carriers (5%).4 5 Despite the high frequency of NPS in ADAD families, relatively little is known about the proportion of ADAD cases who present with predominantly behavioural symptoms. Our aims were to assess the first reported clinical change in symptomatic ADAD, to compare presentations across genotypes, and to compare cognitive performance between behavioural and cognitive-led presentations.

Two-Year Prognostic Utility Of Plasma P217+Tau Across The Alzheimer’S Continuum, A. Feizpour, V. Doré, J. D. Doecke, Z. S. Saad, G. Triana-Baltzer, R. Slemmon, P. Maruff, N. Krishnadas, P. Bourgeat, K. Huang, C. Fowler, S. R. Rainey-Smith, A. I. Bush, L. Ward, J. Robertson, R. N. Martins, C. L. Masters, V. L. Villemagne, J. Fripp, H. C. Kolb, C. C. Rowe

Research outputs 2022 to 2026

Background: Plasma p217+tau has shown high concordance with cerebrospinal fluid (CSF) and positron emission tomography (PET) measures of amyloid- (A ) and tau in Alzheimer’s Disease (AD). However, its association with longitudinal cognition and comparative performance to PET A and tau in predicting cognitive decline are unknown. Objectives: To evaluate whether p217+tau can predict the rate of cognitive decline observed over two-year average follow-up and compare this to prediction based on A (18F-NAV4694) and tau (18F-MK6240) PET. We also explored the sample size required to detect a 30% slowing in cognitive decline in a 2-year trial and selection test cost …

Relationship Of Cognition And Alzheimer’S Disease With Gastrointestinal Tract Disorders: A Large-Scale Genetic Overlap And Mendelian Randomisation Analysis, Emmanuel O. Adewuyi, Eleanor K. O’Brien, Tenielle Porter, Simon M. Laws

Research outputs 2022 to 2026

Emerging observational evidence suggests links between cognitive impairment and a range of gastrointestinal tract (GIT) disorders; however, the mechanisms underlying their relationships remain unclear. Leveraging large-scale genome-wide association studies’ summary statistics, we comprehensively assessed genetic overlap and potential causality of cognitive traits and Alzheimer’s disease (AD) with several GIT disorders. We demonstrate a strong and highly significant inverse global genetic correlation between cognitive traits and GIT disorders — peptic ulcer disease (PUD), gastritis-duodenitis, diverticulosis, irritable bowel syndrome, and gastroesophageal reflux disease (GERD), but not inflammatory bowel disease (IBD). Further analysis detects 35 significant (p < 4.37 × 10 ^{− 5}) bivariate local genetic …

Visually Identified Tau 18f-Mk6240 Pet Patterns In Symptomatic Alzheimer's Disease, Natasha Krishnadas, Kun Huang, Stephanie A. Schultz, Vincent Doré, Pierrick Bourgeat, Anita M. Y. Goh, Fiona Lamb, Svetlana Bozinovski, Samantha C. Burnham, Joanne S. Robertson, Simon M. Laws, Paul Maruff, Colin L. Masters, Victor L. Villemagne, Christopher C. Rowe

Research outputs 2022 to 2026

Background: In Alzheimer's disease, heterogeneity has been observed in the postmortem distribution of tau neurofibrillary tangles. Visualizing the topography of tau in vivo may facilitate clinical trials and clinical practice. Objective: This study aimed to investigate whether tau distribution patterns that are limited to mesial temporal lobe (MTL)/limbic regions, and those that spare MTL regions, can be visually identified using 18F-MK6240, and whether these patterns are associated with different demographic and cognitive profiles. Methods : Tau 18F-MK6240 PET images of 151 amyloid-β positive participants with mild cognitive impairment (MCI) and dementia were visually rated as: tau negative, limbic predominant (LP), …

Comprehensive Analysis Of Epigenetic Clocks Reveals Associations Between Disproportionate Biological Ageing And Hippocampal Volume, Lidija Milicic, Michael Vacher, Tenielle Porter, Vincent Doré, Samantha C. Burnham, Pierrick Bourgeat, Rosita Shishegar, James Doecke, Nicola J. Armstrong, Rick Tankard, Paul Maruff, Colin L. Masters, Christopher C. Rowe, Victor L. Villemagne, Simon M. Laws, Alzheimer’S Disease Neuroimaging Initiative, Australian Imaging Biomarkers And Lifestyle (Aibl) Study

Research outputs 2022 to 2026

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant …

Fifteen Years Of The Australian Imaging, Biomarkers And Lifestyle (Aibl) Study: Progress And Observations From 2,359 Older Adults Spanning The Spectrum From Cognitive Normality To Alzheimer's Disease, Christopher Fowler, Stephanie R. Rainey-Smith, Sabine Bird, Julia Bomke, Pierrick Bourgeat, Belinda M. Brown, Samantha C. Burnham, Ashley I. Bush, Carolyn Chadunow, Steven Collins, James Doecke, Vincent Doré, Kathryn A. Ellis, Lis Evered, Amir Fazlollahi, Jurgen Fripp, Samantha L. Gardener, Simon Gibson, Robert Grenfell, Elise Harrison, Richard Head, Liang Jin, Adrian Kamer, Fiona Lamb, Nicola T. Lautenschlager, Simon M. Laws, Qiao-Xin Li, Lucy Lim, Yen Ying Lim, Andrea Louey, S. Lance Macaulay, Lucy Mackintosh, Ralph N. Martins, Paul Maruff, Colin L. Masters, Simon Mcbride, Lidija Milicica, Madeline Peretti, Kelly Pertile, Tenielle Porter, Morgan Radler, Alan Rembach, Joanne Robertson, Mark Rodrigues, Christopher C. Rowe, Rebecca Rumble, Olivier Salvado, Greg Savage, Brendan Silbert, Magdalene Soh, Hamid R. Sohrabi, Kevin Taddei, Tania Taddei, Christine Thai, Brett Trounson, Regan Tyrrell, Michael Vacher, Shiji Varghese, Victor L. Villemagne, Michael Weinborn, Michael Woodward, Ying Xia, David Ames, Aibl Investigators

Research outputs 2014 to 2021

Background: The Australian Imaging, Biomarkers and Lifestyle (AIBL) Study commenced in 2006 as a prospective study of 1,112 individuals (768 cognitively normal (CN), 133 with mild cognitive impairment (MCI), and 211 with Alzheimer's disease dementia (AD)) as an 'Inception cohort' who underwent detailed ssessments every 18 months. Over the past decade, an additional 1247 subjects have been added as an 'Enrichment cohort' (as of 10 April 2019). Objective: Here we provide an overview of these Inception and Enrichment cohorts of more than 8,500 person-years of investigation. Methods: Participants underwent reassessment every 18 months including comprehensive cognitive testing, neuroimaging (magnetic resonance …

The Effects Of Testosterone Supplementation On Cognitive Functioning In Older Men, Eka Wahjoepramono, Prita Asih, Vilia Aniwiyanti, Kevin Taddei, Satvinder Dhaliwal, Stephanie Fuller, Jonathan Foster, Malcolm Carruthers, Giuseppe Verdile, Hamid R. Sohrabi, Ralph Martins

Research outputs 2014 to 2021

Reduction in testosterone levels in men during aging is associated with cognitive decline and risk of dementia. Animal studies have shown benefits for testosterone supplementation in improving cognition and reducing Alzheimer’s disease pathology. In a randomized, placebo-controlled, crossover study of men with subjective memory complaint and low testosterone levels, we investigated whether testosterone treatment significantly improved performance on various measures of cognitive functioning. Forty-four men were administered a battery of neuropsychological tests to establish the baseline prior to being randomly divided into two groups. The first group (Group A) received 24 weeks of testosterone treatment (T treatment) followed by 4 …