%0 Journal Article %J J Alzheimers Dis %D 2023 %T Plasma Glial Fibrillary Acidic Protein Is Associated with 18F-SMBT-1 PET: Two Putative Astrocyte Reactivity Biomarkers for Alzheimer's Disease. %A Chatterjee, Pratishtha %A Doré, Vincent %A Pedrini, Steve %A Krishnadas, Natasha %A Thota, Rohith %A Bourgeat, Pierrick %A Ikonomovic, Milos D %A Rainey-Smith, Stephanie R %A Burnham, Samantha C %A Fowler, Christopher %A Taddei, Kevin %A Mulligan, Rachel %A Ames, David %A Masters, Colin L %A Fripp, Jurgen %A Rowe, Christopher C %A Martins, Ralph N %A Villemagne, Victor L %K Alzheimer Disease %K Amyloid beta-Peptides %K Apolipoproteins E %K Astrocytes %K Biomarkers %K Brain %K Cognitive Dysfunction %K Glial Fibrillary Acidic Protein %K Humans %K Positron-Emission Tomography %K tau Proteins %X

BACKGROUND: Astrocyte reactivity is an early event along the Alzheimer's disease (AD) continuum. Plasma glial fibrillary acidic protein (GFAP), posited to reflect astrocyte reactivity, is elevated across the AD continuum from preclinical to dementia stages. Monoamine oxidase-B (MAO-B) is also elevated in reactive astrocytes observed using 18F-SMBT-1 PET in AD.

OBJECTIVE: The objective of this study was to evaluate the association between the abovementioned astrocyte reactivity biomarkers.

METHODS: Plasma GFAP and Aβ were measured using the Simoa® platform in participants who underwent brain 18F-SMBT-1 and Aβ-PET imaging, comprising 54 healthy control (13 Aβ-PET+ and 41 Aβ-PET-), 11 mild cognitively impaired (3 Aβ-PET+ and 8 Aβ-PET-) and 6 probable AD (5 Aβ-PET+ and 1 Aβ-PET-) individuals. Linear regressions were used to assess associations of interest.

RESULTS: Plasma GFAP was associated with 18F-SMBT-1 signal in brain regions prone to early Aβ deposition in AD, such as the supramarginal gyrus (SG), posterior cingulate (PC), lateral temporal (LT) and lateral occipital cortex (LO). After adjusting for age, sex, APOE ɛ4 genotype, and soluble Aβ (plasma Aβ42/40 ratio), plasma GFAP was associated with 18F-SMBT-1 signal in the SG, PC, LT, LO, and superior parietal cortex (SP). On adjusting for age, sex, APOE ɛ4 genotype and insoluble Aβ (Aβ-PET), plasma GFAP was associated with 18F-SMBT-1 signal in the SG.

CONCLUSION: There is an association between plasma GFAP and regional 18F-SMBT-1 PET, and this association appears to be dependent on brain Aβ load.

%B J Alzheimers Dis %V 92 %P 615-628 %8 2023 %G eng %N 2 %R 10.3233/JAD-220908 %0 Journal Article %J J Alzheimers Dis %D 2018 %T Associations of Dietary Protein and Fiber Intake with Brain and Blood Amyloid-β. %A Fernando, W M A D Binosha %A Rainey-Smith, Stephanie R %A Gardener, Samantha L %A Villemagne, Victor L %A Burnham, Samantha C %A Macaulay, S Lance %A Brown, Belinda M %A Gupta, Veer Bala %A Sohrabi, Hamid R %A Weinborn, Michael %A Taddei, Kevin %A Laws, Simon M %A Goozee, Kathryn %A Ames, David %A Fowler, Christopher %A Maruff, Paul %A Masters, Colin L %A Salvado, Olivier %A Rowe, Christopher C %A Martins, Ralph N %K Aged %K Alzheimer Disease %K Amyloid beta-Peptides %K Australia %K Biomarkers %K Brain %K Cognition %K Cohort Studies %K Cross-Sectional Studies %K Dietary Fiber %K Dietary Proteins %K Female %K Humans %K Logistic Models %K Male %K Middle Aged %K Neuropsychological Tests %K Positron-Emission Tomography %X

Accumulating evidence suggests a diet high in protein and fiber may confer some protection against Alzheimer's disease (AD). However, no human studies to-date have assessed the relationship between protein and fiber intake, and plasma and brain amyloid-β (Aβ). Consequently, this cross-sectional study, investigated the association of self-reported dietary intakes of protein and fiber, with plasma and brain Aβ burden (n = 541, and n = 162 respectively), in a well-characterized cohort of cognitively normal older adults, drawn from the larger Australian Imaging, Biomarkers and Lifestyle (AIBL) study of aging. We observed 12.59 and 8.43 higher odds of 'high' brain Aβ burden (PiB PET SUVR≥1.5) if protein intake fell in the lowest and middle tertile, respectively, compared to the highest tertile (p = 0.008; p = 0.013). Thus, in this cohort, the more protein consumed, the less likelihood of 'high' Aβ burden in the brain. No other significant associations were observed. The results of this study highlight the potentially protective impact of high dietary protein intake on brain Aβ burden in older adults, before objective memory decline is apparent. While longitudinal validation is required, these findings may assist in the development of dietary approaches aimed at preventing or delaying AD onset.

%B J Alzheimers Dis %V 61 %P 1589-1598 %8 2018 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/29376865?dopt=Abstract %R 10.3233/JAD-170742 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Non-Verbal Episodic Memory Deficits in Primary Progressive Aphasias are Highly Predictive of Underlying Amyloid Pathology. %A Ramanan, Siddharth %A Flanagan, Emma %A Leyton, Cristian E %A Villemagne, Victor L %A Rowe, Christopher C %A Hodges, John R %A Hornberger, Michael %K Aged %K Alzheimer Disease %K Amyloid %K Aniline Compounds %K Aphasia, Primary Progressive %K Brain %K Diagnosis, Differential %K Female %K Humans %K Logistic Models %K Male %K Memory, Episodic %K Neuropsychological Tests %K Positron-Emission Tomography %K Radiopharmaceuticals %K Speech Perception %K Thiazoles %X

Diagnostic distinction of primary progressive aphasias (PPA) remains challenging, in particular for the logopenic (lvPPA) and nonfluent/agrammatic (naPPA) variants. Recent findings highlight that episodic memory deficits appear to discriminate these PPA variants from each other, as only lvPPA perform poorly on these tasks while having underlying amyloid pathology similar to that seen in amnestic dementias like Alzheimer's disease (AD). Most memory tests are, however, language based and thus potentially confounded by the prevalent language deficits in PPA. The current study investigated this issue across PPA variants by contrasting verbal and non-verbal episodic memory measures while controlling for their performance on a language subtest of a general cognitive screen. A total of 203 participants were included (25 lvPPA; 29 naPPA; 59 AD; 90 controls) and underwent extensive verbal and non-verbal episodic memory testing, with a subset of patients (n = 45) with confirmed amyloid profiles as assessed by Pittsburgh Compound B and PET. The most powerful discriminator between naPPA and lvPPA patients was a non-verbal recall measure (Rey Complex Figure delayed recall), with 81% of PPA patients classified correctly at presentation. Importantly, AD and lvPPA patients performed comparably on this measure, further highlighting the importance of underlying amyloid pathology in episodic memory profiles. The findings demonstrate that non-verbal recall emerges as the best discriminator of lvPPA and naPPA when controlling for language deficits in high load amyloid PPA cases.

%B J Alzheimers Dis %V 51 %P 367-76 %8 2016 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/26890745?dopt=Abstract %R 10.3233/JAD-150752 %0 Journal Article %J Brain %D 2011 %T 18F-THK523: a novel in vivo tau imaging ligand for Alzheimer's disease. %A Fodero-Tavoletti, Michelle T %A Okamura, Nobuyuki %A Furumoto, Shozo %A Mulligan, Rachel S %A Connor, Andrea R %A McLean, Catriona A %A Cao, Diana %A Rigopoulos, Angela %A Cartwright, Glenn A %A O'Keefe, Graeme %A Gong, Sylvia %A Adlard, Paul A %A Barnham, Kevin J %A Rowe, Christopher C %A Masters, Colin L %A Kudo, Yukitsuka %A Cappai, Roberto %A Yanai, Kazuhiko %A Villemagne, Victor L %K Alzheimer Disease %K Analysis of Variance %K Aniline Compounds %K Animals %K Autoradiography %K Binding Sites %K Brain %K Female %K Fluorodeoxyglucose F18 %K Humans %K Immunohistochemistry %K Male %K Mice %K Quinolines %K Radiopharmaceuticals %K tau Proteins %X

While considerable effort has focused on developing positron emission tomography β-amyloid imaging radiotracers for the early diagnosis of Alzheimer's disease, no radiotracer is available for the non-invasive quantification of tau. In this study, we detail the characterization of (18)F-THK523 as a novel tau imaging radiotracer. In vitro binding studies demonstrated that (18)F-THK523 binds with higher affinity to a greater number of binding sites on recombinant tau (K18Δ280K) compared with β-amyloid(1-42) fibrils. Autoradiographic and histofluorescence analysis of human hippocampal serial sections with Alzheimer's disease exhibited positive THK523 binding that co-localized with immunoreactive tau pathology, but failed to highlight β-amyloid plaques. Micro-positron emission tomography analysis demonstrated significantly higher retention of (18)F-THK523 (48%; P < 0.007) in tau transgenic mice brains compared with their wild-type littermates or APP/PS1 mice. The preclinical examination of THK523 has demonstrated its high affinity and selectivity for tau pathology both in vitro and in vivo, indicating that (18)F-THK523 fulfils ligand criteria for human imaging trials.

%B Brain %V 134 %P 1089-100 %8 2011 Apr %G eng %N Pt 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/21436112?dopt=Abstract %R 10.1093/brain/awr038 %0 Journal Article %J Alzheimers Dement %D 2011 %T Toward defining the preclinical stages of Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease. %A Sperling, Reisa A %A Aisen, Paul S %A Beckett, Laurel A %A Bennett, David A %A Craft, Suzanne %A Fagan, Anne M %A Iwatsubo, Takeshi %A Jack, Clifford R %A Kaye, Jeffrey %A Montine, Thomas J %A Park, Denise C %A Reiman, Eric M %A Rowe, Christopher C %A Siemers, Eric %A Stern, Yaakov %A Yaffe, Kristine %A Carrillo, Maria C %A Thies, Bill %A Morrison-Bogorad, Marcelle %A Wagster, Molly V %A Phelps, Creighton H %K Alzheimer Disease %K Biomarkers %K Cognition Disorders %K Humans %K National Institute on Aging (U.S.) %K Practice Guidelines as Topic %K United States %X

The pathophysiological process of Alzheimer's disease (AD) is thought to begin many years before the diagnosis of AD dementia. This long "preclinical" phase of AD would provide a critical opportunity for therapeutic intervention; however, we need to further elucidate the link between the pathological cascade of AD and the emergence of clinical symptoms. The National Institute on Aging and the Alzheimer's Association convened an international workgroup to review the biomarker, epidemiological, and neuropsychological evidence, and to develop recommendations to determine the factors which best predict the risk of progression from "normal" cognition to mild cognitive impairment and AD dementia. We propose a conceptual framework and operational research criteria, based on the prevailing scientific evidence to date, to test and refine these models with longitudinal clinical research studies. These recommendations are solely intended for research purposes and do not have any clinical implications at this time. It is hoped that these recommendations will provide a common rubric to advance the study of preclinical AD, and ultimately, aid the field in moving toward earlier intervention at a stage of AD when some disease-modifying therapies may be most efficacious.

%B Alzheimers Dement %V 7 %P 280-92 %8 2011 May %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/21514248?dopt=Abstract %R 10.1016/j.jalz.2011.03.003