Medicine and Health Sciences Commons^™

Rna Editing Of Microtubule-Associated Protein Tau Circular Rnas Promotes Their Translation And Tau Tangle Formation, Justin Ralph Welden, Giorgi Margvelani, Karol Andrea Arizaca Maquera, Bhavani Gudlavalleti, Sandra C. Miranda Sardón, Alexandre Rosa Campos, Noémie Robil, Daniel C. Lee, Alvaro G. Hernandez, Wang-Xia Wang, Jing Di, Pierre De La Grange, Peter T. Nelson, Stefan Stamm

Sanders-Brown Center on Aging Faculty Publications

Aggregation of the microtubule-associated protein tau characterizes tauopathies, including Alzheimer’s disease and frontotemporal lobar degeneration (FTLD-Tau). Gene expression regulation of tau is complex and incompletely understood. Here we report that the human tau gene (MAPT) generates two circular RNAs (circRNAs) through backsplicing of exon 12 to either exon 7 (12→7 circRNA) or exon 10 (12→10 circRNA). Both circRNAs lack stop codons. The 12→7 circRNA contains one start codon and is translated in a rolling circle, generating a protein consisting of multimers of the microtubule-binding repeats R1–R4. For the 12→10 circRNA, a start codon can be introduced by two …

Apoe Ε2 Resilience For Alzheimer’S Disease Is Mediated By Plasma Lipid Species: Analysis Of Three Independent Cohort Studies, Tingting Wang, Kevin Huynh, Corey Giles, Natalie A. Mellett, Thy Duong, Anh Nguyen, Wei L. F. Lim, Alex A. T. Smith, Gavriel Olshansky, Gemma Cadby, Joseph Hung, Jennie Hui, John Beilby, Gerald F. Watts, Pratishtha Chatterjee, Ian Martins, Simon Laws, Ashley I. Bush, Christopher C. Rowe, Victor L. Villemagne, David Ames, Colin L. Masters, Kevin Taddei, Vincent Doré, Jürgen Fripp, Matthias Arnold, Gabi Kastenmüller, Kwangsik Nho, Andrew J. Saykin, Rebecca Baillie, Xianlin Han, Ralph N. Martins, Eric K. Moses, Rima Kaddurah-Daouk, Peter J. Meikle

Research outputs 2022 to 2026

Introduction:

The apolipoprotein E (APOE) genotype is the strongest genetic risk factor for late-onset Alzheimer's disease. However, its effect on lipid metabolic pathways, and their mediating effect on disease risk, is poorly understood.

Methods:

We performed lipidomic analysis on three independent cohorts (the Australian Imaging, Biomarkers and Lifestyle [AIBL] flagship study, n = 1087; the Alzheimer's Disease Neuroimaging Initiative [ADNI] 1 study, n = 819; and the Busselton Health Study [BHS], n = 4384), and we defined associations between APOE ε2 and ε4 and 569 plasma/serum lipid species. Mediation analysis defined the proportion of the treatment effect of the APOE …

Transcriptional Profiles In Olfactory Pathway-Associated Brain Regions Of African Green Monkeys: Associations With Age And Alzheimer’S Disease Neuropathology, Jacob D Negrey, Dorothy L Dobbins, Timothy D Howard, Karin E Borgmann-Winter, C G Hahn, Sergey Kalinin, Douglas L Feinstein, Suzanne Craft, Carol A Shively, Thomas C Register

Department of Neuroscience Faculty Papers

Introduction: Olfactory impairment in older individuals is associated with an increased risk of Alzheimer's disease (AD). Characterization of age versus neuropathology-associated changes in the brain olfactory pathway may elucidate processes underlying early AD pathogenesis. Here, we report age versus AD neuropathology-associated differential transcription in four brain regions in the olfactory pathway of 10 female African green monkeys (vervet, Chlorocebus aethiops sabaeus), a well-described model of early AD-like neuropathology.

Methods: Transcriptional profiles were determined by microarray in the olfactory bulb (OB), piriform cortex (PC), temporal lobe white matter (WM), and inferior temporal cortex (ITC). Amyloid beta (Aβ) plaque load in …

Plasma High-Density Lipoprotein Cargo Is Altered In Alzheimer's Disease And Is Associated With Regional Brain Volume, Steve Pedrini, James D. Doecke, Eugene Hone, Penghao Wang, Rohith Thota, Ashley I. Bush, Christopher C. Rowe, Vincent Dore, Victor L. Villemagne, David Ames, Stephanie Rainey-Smith, Giuseppe Verdile, Hamid R. Sohrabi, Manfred R. Raida, Kevin Taddei, Sam Gandy, Colin L. Masters, Pratishtha Chatterjee, Ralph N. Martins, Aibl Research Group

Research outputs 2022 to 2026

Cholesterol levels have been repeatedly linked to Alzheimer's Disease (AD), suggesting that high levels could be detrimental, but this effect is likely attributed to Low-Density Lipoprotein (LDL) cholesterol. On the other hand, High-Density Lipoproteins (HDL) cholesterol levels have been associated with reduced brain amyloidosis and improved cognitive function. However, recent findings have suggested that HDL-functionality, which depends upon the HDL-cargo proteins associated with HDL, rather than HDL levels, appears to be the key factor, suggesting a quality over quantity status. In this report, we have assessed the HDL-cargo (Cholesterol, ApoA-I, ApoA-II, ApoC-I, ApoC-III, ApoD, ApoE, ApoH, ApoJ, CRP, and SAA) …

Understanding The Relationship Between Age-Related Hearing Loss And Alzheimer's Disease: A Narrative Review, Hadeel Y. Tarawneh, Dona M. P. Jayakody, Hamid R. Sohrabi, Ralph N. Martins, Wilhelmina H.A.M. Mulders

Research outputs 2022 to 2026

Evidence suggests that hearing loss (HL), even at mild levels, increases the long-term risk of cognitive decline and incident dementia. Hearing loss is one of the modifiable risk factors for dementia, with approximately 4 million of the 50 million cases of dementia worldwide possibly attributed to untreated HL. This paper describes four possible mechanisms that have been suggested for the relationship between age-related hearing loss (ARHL) and Alzheimer's disease (AD), which is the most common form of dementia. The first mechanism suggests mitochondrial dysfunction and altered signal pathways due to aging as a possible link between ARHL and AD. The …

The Trend Of Disruption In The Functional Brain Network Topology Of Alzheimer’S Disease, Alireza Fathian, Yousef Jamali, Mohammad Reza Raoufy, The Alzheimer's Disease Neuroimaging Initiative, Michael W. Weiner, Norbert Schuf, Howard J. Rosen, Bruce L. Miller, Thomas Neylan, Jacqueline Hayess, Shannon Finley, Paul Aisen, Zaven Khachaturian, Ronald G. Thomas, Charles D. Smith, Gregory A. Jicha, Peter A. Hardy, Partha Sinha, Elizabeth Oates, Gary Conrad

Sanders-Brown Center on Aging Faculty Publications

Alzheimer’s disease (AD) is a progressive disorder associated with cognitive dysfunction that alters the brain’s functional connectivity. Assessing these alterations has become a topic of increasing interest. However, a few studies have examined different stages of AD from a complex network perspective that cover different topological scales. This study used resting state fMRI data to analyze the trend of functional connectivity alterations from a cognitively normal (CN) state through early and late mild cognitive impairment (EMCI and LMCI) and to Alzheimer’s disease. The analyses had been done at the local (hubs and activated links and areas), meso (clustering, assortativity, and …

Adult Day Services In Maine: Benefits, Challenges, And Opportunities, Elizabeth Gattine Jd, Eileen Griffin Jd, Kimberly I. Snow Mhsa, Ba

Disability & Aging

In Maine and nationally, adult day services tend to be underfunded and underutilized compared to other types of long term services and supports (LTSS). In part, investment in adult day services is hampered by a lack of standardized data collection and limited research on issues of accessibility, cost-effectiveness, and the impact of adult day services on the broader health system. Lack of uniformity in state regulatory frameworks for licensing, program design, service delivery, and other administrative requirements further complicates cross-state comparisons. Considering these limitations, a key goal of this report is to provide a more detailed and comprehensive understanding of …

Systemic Perturbations Of The Kynurenine Pathway Precede Progression To Dementia Independently Of Amyloid-Β, Marcela Cespedes, Kelly R. Jacobs, Paul Maruff, Alan Rembach, Christopher J. Fowler, Brett Trounson, Kelly K. Pertile, Rebecca L. Rumble, Stephanie R. Rainey-Smith, Christopher C. Rowe, Victor L. Villemagne, Pierrick Bourgeat, Chai K. Lim, Pratishtha Chatterjee, Ralph N. Martins, Arne Ittner, Colin L. Masters, James D. Doecke, Gilles J. Guillemin, David B. Lovejoy

Research outputs 2022 to 2026

Increasing evidence suggests that kynurenine pathway (KP) dyshomeostasis may promote disease progression in dementia. Studies in Alzheimer's disease (AD) patients confirm KP dyshomeostasis in plasma and cerebrospinal fluid (CSF) which correlates with amyloid-β and tau pathology. Herein, we performed the first comprehensive study assessing baseline levels of KP metabolites in participants enrolling in the Australian Imaging Biomarkers Flagship Study of Aging. Our purpose was to test the hypothesis that changes in KP metabolites may be biomarkers of dementia processes that are largely silent. We used a cross-sectional analytical approach to assess non-progressors (N = 73); cognitively normal (CN) or mild …

Pineal Cyst Apoplexy And Memory Loss: A Novel Complication, Areez Shafqat, Hanin Jaber Algethami, Shameel Shafqat, Syed Shafqat Ul Islam

Medical College Documents

An 8-year-old boy presented to our hospital complaining of a bilateral headache associated with episodes of anterograde amnesia. He had a road traffic accident 3 years ago when a computed tomography (CT) scan revealed traumatic brain injury. In addition, a small pineal cyst (PC) was noted with minor intramural calcifications. A follow-up CT a day later demonstrated increased density in the pineal gland of 60 Hounsfield Units, suggestive of apoplectic changes in the PC. However, the patient was lost to follow-up and presented with memory loss a year and a half later, upon which CT and magnetic resonance imaging revealed …

Sex Differences In The Genetic Architecture Of Cognitive Resilience To Alzheimer’S Disease, Jaclyn M. Eissman, Logan Dumitrescu, Emily R. Mahoney, Alexandra N. Smith, Shubhabrata Mukherjee, Michael L. Lee, Phoebe Scollard, Seo Eun Choi, William S. Bush, Corinne D. Engelman, Qiongshi Lu, David W. Fardo, Emily H. Trittschuh, Jesse Mez, Catherine C. Kaczorowski, Hector Hernandez Saucedo, Keith F. Widaman, Rachel F. Buckley, Michael J. Properzi, Elizabeth C. Mormino, Hyun Sik Yang, Theresa M. Harrison, Trey Hedden, Kwangsik Nho, Shea J. Andrews, Douglas Tommet, Niran Hadad, R. Elizabeth Sanders, Douglas M. Ruderfer, Katherine A. Gifford, Xiaoyuan Zhong, Neha S. Raghavan, Badri Vardarajan, Margaret A. Pericak-Vance, Lindsay A. Farrer, Li San Wang, Carlos Cruchaga, Gerard D. Schellenberg, Nancy J. Cox, Jonathan L. Haines, C. Dirk Keene, Andrew J. Saykin, Eric B. Larson, Reisa A. Sperling, Richard Mayeux, Michael L. Cuccaro, David A. Bennett, Julie A. Schneider, Paul K. Crane, Angela L. Jefferson, Timothy J. Hohman

Sanders-Brown Center on Aging Faculty Publications

Approximately 30% of elderly adults are cognitively unimpaired at time of death despite the presence of Alzheimer's disease neuropathology at autopsy. Studying individuals who are resilient to the cognitive consequences of Alzheimer's disease neuropathology may uncover novel therapeutic targets to treat Alzheimer's disease. It is well established that there are sex differences in response to Alzheimer's disease pathology, and growing evidence suggests that genetic factors may contribute to these differences. Taken together, we sought to elucidate sex-specific genetic drivers of resilience.

We extended our recent large scale genomic analysis of resilience in which we harmonized cognitive data across four cohorts …

Making The Case For The Accelerated Withdrawal Of Aducanumab, Peter J. Whitehouse

Faculty Scholarship

U.S. Food and Drug Administration-s (FDA) approval of aducanumab (Aduhelm® in the US) as a treatment for mild cognitive impairment of the Alzheimer type and Alzheimer-s disease has raised such major concerns about efficacy, safety, FDA processes, and regulatory capture that Biogen-s license to market this biologic should be immediately withdrawn. Aducanumab has not demonstrated benefit to patients, failed to meet regulatory guidelines, and is likely to cause both individual and societal harm.

The Impact Of Cognitive Rehabilitation Therapy On Alzheimer's Disease, Kelsey Hall

MSN Capstone Projects

The number of people suffering from Alzheimer’s disease (AD) rises daily. This is a devastating disease for the patients, significant others, and families to have to experience. “Epidemiological data confirm what retirees have observed: about 30-50% of those living to their mid-80’s will have suffered a marked loss of cognitive ability, a harbinger of advanced AD, or will have suffered advanced AD. Further, the tragedy of AD affecting loved partners takes an enormous toll on their healthier partners” (Reid et al., 2017).

The current treatment regimen for Alzheimer’s disease includes medication therapy. Evidence has shown that there are only small …

New Insights Into The Genetic Etiology Of Alzheimer’S Disease And Related Dementias, Céline Bellenguez, Fahri Küçükali, Iris Jansen, Luca Kleineidam, Sonia Moreno-Grau, Najaf Amin, Adam C. Naj, Rafael Campos-Martin, David W. Fardo, Yuriko Kastumata, Erin L. Abner, Radb, Gr@Ace, Degesco, Eadi, Gerad, Demgene, Finngen, Adgc, Charge

Sanders-Brown Center on Aging Faculty Publications

Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly …

The Association Between Alzheimer's Disease-Related Markers And Physical Activity In Cognitively Normal Older Adults, Steve Pedrini, Pratishtha Chatterjee, Akinori Nakamura, Michelle Tegg, Eugene Hone, Stephanie R. Rainey-Smith, Christopher C. Rowe, Vincent Dore, Victor L. Villemagne, David Ames, Naoki Kaneko, Samantha L. Gardener, Kevin Taddei, Binosha Fernando, Ian Martins, Prashant Bharadwaj, Hamid R. Sohrabi, Colin L. Masters, Belinda Brown, Ralph N. Martins, Aibl Research Group

Research outputs 2022 to 2026

Previous studies have indicated that physical activity may be beneficial in reducing the risk for Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. The goal of this study was to evaluate the relationship between habitual physical activity levels and brain amyloid deposition and AD-related blood biomarkers (i.e., measured using a novel high-performance mass spectrometry-based assay), in apolipoprotein E (APOE) ε4 carriers and noncarriers. We evaluated 143 cognitively normal older adults, all of whom had brain amyloid deposition assessed using positron emission tomography and had their physical activity levels measured using the International Physical Activity Questionnaire (IPAQ). We …

Blood Biomarkers For Cognitive Decline And Clinical Progression In A Mexican American Cohort, Mitzi M. Gonzales, Chen-Pin Wang, Meghan I. Short, Danielle M. Parent, Tiffany Kautz, Daniel Maccarthy, Claudia L. Satizabal, David Andrés González, Donald R. Royal, Gladys E. Maestre

School of Medicine Publications and Presentations

Introduction: The clinical translation of biofluid markers for dementia requires validation in diverse cohorts. The study goal was to evaluate if blood biomarkers reflecting diverse pathophysiological processes predict disease progression in Mexican American adults.

Methods: Mexican American adults (n = 745), 50 years of age and older, completed annual assessments over a mean of 4 years. Serum collected at baseline was assayed for total tau, neurofilament light (NFL), ubiquitin carboxyl‐terminal hydrolase LI, glial fibrillary acidic protein (GFAP), soluble cluster of differentiation 14 (sCD14), and chitinase‐3‐like protein 1 (YKL‐40).

Results: Higher GFAP and NFL were associated with global …

A Novel Non‑Selective Atypical Pkc Agonist Could Protect Neuronal Cell Line From A Β ‑Oligomer Induced Toxicity By Suppressing A Β Generation, Dongmei Zou, Qian Li, Wenyang Pan, Peng Chen, Miao Sun, Xiaofeng Bao

Publications and Research

Atypical protein kinase C (aPKCs) serve key functions in embryonic development by regulating apical-basal polarity. Previous studies have shed light on their roles during adulthood, especially in the development of Alzheimer's disease (AD). Although the crystal structure of PKCι has been resolved, an agonist of aPKCs remains to be discovered. In the present study, by using the Discovery Studio program and LibDock methodology, a small molecule library (K66-X4436 KINA Set) of compounds were screened for potential binding to PKCι. Subsequently, the computational docking results were validated using affinity selection-mass spectrometry, before in vitro kinase activity was used to determine the …

Aducanumab, A Novel Anti-Amyloid Monoclonal Antibody, For The Treatment Of Alzheimer’S Disease: A Comprehensive Review, Hannah W. Haddad, Garett W. Malone, Nicholas J. Comardelle, Arielle E. Degueure, Adam M. Kaye, Alan David Kaye

School of Pharmacy Faculty Articles

Alzheimer’s disease (AD) is the most common form of dementia affecting millions of individuals, including family members who often take on the role as caregiver. This debilitating disease reportedly consumes 8% of the total United States healthcare expenditure, with medical and nursing outlays accounting for an estimated $290 billion. Cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists have historically been the most widely used pharmacologic therapies for patients with AD, however, these drugs are not curative. This review discusses the epidemiology, pathophysiology, risk factors, presentation, and current treatment of AD followed by the role of the novel monoclonal antibody, aducanumab, in treatment …

Therapeutic Treatment With The Anti-Inflammatory Drug Candidate Mw151 May Partially Reduce Memory Impairment And Normalizes Hippocampal Metabolic Markers In A Mouse Model Of Comorbid Amyloid And Vascular Pathology, David J. Braun, David K. Powell, Christopher J. Mclouth, Saktimayee M. Roy, D. Martin Watterson, Linda J. Van Eldik

Neuroscience Faculty Publications

Alzheimer's disease (AD) is the leading cause of dementia in the elderly, but therapeutic options are lacking. Despite long being able to effectively treat the ill-effects of pathology present in various rodent models of AD, translation of these strategies to the clinic has so far been disappointing. One potential contributor to this situation is the fact that the vast majority of AD patients have other dementia-contributing comorbid pathologies, the most common of which are vascular in nature. This situation is modeled relatively infrequently in basic AD research, and almost never in preclinical studies. As part of our efforts to develop …

Editorial: Infection, Inflammation, And Neurodegeneration: A Critical Path To Alzheimer's Disease, Volume Ii., Roberta Mancuso, Simone Agostini, Denah Appelt, Brian J. Balin

PCOM Scholarly Papers

No abstract available

Cerebrospinal Fluid Levels Of Fatty Acid–Binding Protein 3 Are Associated With Likelihood Of Amyloidopathy In Cognitively Healthy Individuals, Kunal Dhiman, Victor L. Villemagne, Christopher Fowler, Pierrick Bourgeat, Qiao-Xin Li, Steven Collins, Christopher C. Rowe, Colin L. Masters, David Ames, Kaj Blennow, Henrik Zetterberg, Ralph N. Martins, Veer Gupta

Research outputs 2022 to 2026

Introduction: Fatty acid–binding protein 3 (FABP3) is a biomarker of neuronal membrane disruption, associated with lipid dyshomeostasis—a notable Alzheimer's disease (AD) pathophysiological change. We assessed the association of cerebrospinal fluid (CSF) FABP3 levels with brain amyloidosis and the likelihood/risk of developing amyloidopathy in cognitively healthy individuals. Methods: FABP3 levels were measured in CSF samples of cognitively healthy participants, > 60 years of age (n = 142), from the Australian Imaging, Biomarkers & Lifestyle Flagship Study of Ageing (AIBL). Results: FABP3 levels were positively associated with baseline brain amyloid beta (Aβ) load as measured by standardized uptake value ratio (SUVR, standardized β …

Plasma P-Tau181/Aβ1-42 Ratio Predicts Aβ-Pet Status And Correlates With Csf-P-Tau181/Aβ1-42 And Future Cognitive Decline, Christopher J. Fowler, Erik Stoops, Stephanie R. Rainey-Smith, Eugeen Vanmechelen, Jeroen Vanbrabant, Nele Dewit, Kimberley Mauroo, Paul Maruff, Christopher C. Rowe, Jurgen Fripp, Qiao-Xin Li, Pierrick Bourgeat, Steven J. Collins, Ralph N. Martins, Colin L. Masters, James D. Doecke

Research outputs 2022 to 2026

Background: In Alzheimer's disease (AD), plasma amyloid beta (Aβ)1-42 and phosphorylated tau (p-tau) predict high amyloid status from Aβ positron emission tomography (PET); however, the extent to which combination of these plasma assays can predict remains unknown. Methods: Prototype Simoa assays were used to measure plasma samples from participants who were either cognitively normal (CN) or had mild cognitive impairment (MCI)/AD in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. Results: The p-tau181/Aβ1-42 ratio showed the best prediction of Aβ-PET across all participants (area under the curve [AUC] = 0.905, 95% confidence interval [CI]: 0.86–0.95) and in CN (AUC = …

Plasma P217+Tau Versus Nav4694 Amyloid And Mk6240 Tau Pet Across The Alzheimer's Continuum, Vincent Doré, James D. Doecke, Ziad S. Saad, Gallen Triana-Baltzer, Randy Slemmon, Natasha Krishnadas, Pierrick Bourgeat, Kun Huang, Samantha Burnham, Christopher Fowler, Stephanie R. Rainey-Smith, Ashley I. Bush, Larry Ward, Jo Robertson, Ralph N. Martins, Colin L. Masters, Victor L. Villemagne, Jurgen Fripp, Hartmuth C. Kolb, Christopher C. Rowe

Research outputs 2022 to 2026

Introduction: We evaluated a new Simoa plasma assay for phosphorylated tau (P-tau) at aa217 enhanced by additional p-tau sites (p217+tau). Methods: Plasma p217+tau levels were compared to 18F-NAV4694 amyloid beta (Aβ) positron emission tomography (PET) and 18F-MK6240 tau PET in 174 cognitively impaired (CI) and 223 cognitively unimpaired (CU) participants. Results: Compared to Aβ− CU, the plasma levels of p217+tau increased 2-fold in Aβ+ CU and 3.5-fold in Aβ+ CI. In Aβ− the p217+tau levels did not differ significantly between CU and CI. P217+tau correlated with Aβ centiloids P =.67 (CI, P =.64; CU, P =.45) and tau SUVRMT P …

An Il1rl1 Genetic Variant Lowers Soluble St2 Levels And The Risk Effects Of Apoe-Ε4 In Female Patients With Alzheimer’S Disease, Yuanbing Jiang, Xiaopu Zhou, Hiu Yi Wong, Li Ouyang, Fanny C. F. Ip, Vicky M. N. Chau, Shun-Fat Lau, Wei Wu, Daniel Y. K. Wong, Heukjin Seo, Wing-Yu Fu, Nicole C. H. Lai, Yuewen Chen, Yu Chen, Estella P.S. Tong, Alzheimer’S Disease Neuroimaging Initiative, Vincent C. T. Mok, Timothy C. Y. Kwok, Kin Y. Mok, Maryam Shoai, Benoit Lehallier, Patricia Morán Losada, Eleanor O'Brien, Tenielle Porter, Simon Laws, John Hardy, Tony Wyss-Coray, Colin L. Masters, Amy K.Y. Fu, Nancy Y. Ip

Research outputs 2022 to 2026

Changes in the levels of circulating proteins are associated with Alzheimer’s disease (AD), whereas their pathogenic roles in AD are unclear. Here, we identified soluble ST2 (sST2), a decoy receptor of interleukin-33–ST2 signaling, as a new disease-causing factor in AD. Increased circulating sST2 level is associated with more severe pathological changes in female individuals with AD. Genome-wide association analysis and CRISPR–Cas9 genome editing identified rs1921622, a genetic variant in an enhancer element of IL1RL1, which downregulates gene and protein levels of sST2. Mendelian randomization analysis using genetic variants, including rs1921622, demonstrated that decreased sST2 levels lower AD …

Exploring Discordant Low Amyloid Beta And High Neocortical Tau Positron Emission Tomography Cases, Natasha Krishnadas, Vincent Doré, Simon M. Laws, Tenielle Porter, Fiona Lamb, Svetlana Bozinovski, Victor L. Villemagne, Christopher C. Rowe

Research outputs 2022 to 2026

Introduction: Neocortical 3R4R (3-repeat/4-repeat) tau aggregates are rarely observed in the absence of amyloid beta (Aβ). 18F-MK6240 binds specifically to the 3R4R form of tau that is characteristic of Alzheimer's disease (AD). We report four cases with negative Aβ, but positive tau positron emission tomography (PET) findings. Methods: All Australian Imaging, Biomarkers and Lifestyle study of aging (AIBL) study participants with Aβ (18F-NAV4694) and tau (18F-MK6240) PET scans were included. Centiloid < 25 defined negative Aβ PET (Aβ–). The presence of neocortical tau was defined quantitatively and visually. Results: Aβ– PET was observed in 276 participants. Four of these participants (one cognitively unimpaired [CU], two mild cognitive impairment [MCI], one AD) had tau tracer retention in a pattern consistent with Braak tau stages V to VI. Fluid biomarkers supported a diagnosis of AD. In silico analysis of APP, PSEN1, PSEN2, and MAPT genes did not identify relevant functional mutations. Discussion: Discordant cases were infrequent (1.4% of all Aβ– participants). In these cases, the Aβ PET ligand may not be detecting the Aβ that is present.

A Large-Scale Genome-Wide Cross-Trait Analysis Reveals Shared Genetic Architecture Between Alzheimer’S Disease And Gastrointestinal Tract Disorders, Emmanuel O. Adewuyi, Eleanor K. O'Brien, Dale R. Nyholt, Tenielle Porter, Simon Laws

Research outputs 2022 to 2026

Consistent with the concept of the gut-brain phenomenon, observational studies suggest a relationship between Alzheimer’s disease (AD) and gastrointestinal tract (GIT) disorders; however, their underlying mechanisms remain unclear. Here, we analyse several genome-wide association studies (GWAS) summary statistics (N = 34,652–456,327), to assess the relationship of AD with GIT disorders. Findings reveal a positive significant genetic overlap and correlation between AD and gastroesophageal reflux disease (GERD), peptic ulcer disease (PUD), gastritis-duodenitis, irritable bowel syndrome and diverticulosis, but not inflammatory bowel disease. Cross-trait meta-analysis identifies several loci (P_{meta-analysis} < 5 × 10⁻⁸) shared by AD and GIT disorders (GERD and PUD) including …