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Browsing by Author "Graff-Radford, Jonathan"
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Item Global neuropathologic severity of Alzheimer's disease and locus coeruleus vulnerability influences plasma phosphorylated tau levels(Springer, 2022-12-27) Murray, Melissa E.; Moloney, Christina M.; Kouri, Naomi; Syrjanen, Jeremy A.; Matchett, Billie J.; Rothberg, Darren M.; Tranovich, Jessica F.; Hicks Sirmans, Tiffany N.; Wiste, Heather J.; Boon, Baayla D. C.; Nguyen, Aivi T.; Reichard, R. Ross; Dickson, Dennis W.; Lowe, Val J.; Dage, Jeffrey L.; Petersen, Ronald C.; Jack, Clifford R., Jr.; Knopman , David S.; Vemuri, Prashanthi; Graff-Radford, Jonathan; Mielke, Michelle M.; Neurology, School of MedicineBackground Advances in ultrasensitive detection of phosphorylated tau (p-tau) in plasma has enabled the use of blood tests to measure Alzheimer’s disease (AD) biomarker changes. Examination of postmortem brains of participants with antemortem plasma p-tau levels remains critical to understanding comorbid and AD-specific contribution to these biomarker changes. Methods We analyzed 35 population-based Mayo Clinic Study of Aging participants with plasma p-tau at threonine 181 and threonine 217 (p-tau181, p-tau217) available within 3 years of death. Autopsied participants included cognitively unimpaired, mild cognitive impairment, AD dementia, and non-AD neurodegenerative disorders. Global neuropathologic scales of tau, amyloid-β, TDP-43, and cerebrovascular disease were examined. Regional digital pathology measures of tau (phosphorylated threonine 181 and 217 [pT181, pT217]) and amyloid-β (6F/3D) were quantified in hippocampus and parietal cortex. Neurotransmitter hubs reported to influence development of tangles (nucleus basalis of Meynert) and amyloid-β plaques (locus coeruleus) were evaluated. Results The strongest regional associations were with parietal cortex for tau burden (p-tau181 R = 0.55, p = 0.003; p-tau217 R = 0.66, p < 0.001) and amyloid-β burden (p-tau181 R = 0.59, p < 0.001; p-tau217 R = 0.71, p < 0.001). Linear regression analysis of global neuropathologic scales explained 31% of variability in plasma p-tau181 (Adj. R2 = 0.31) and 59% in plasma p-tau217 (Adj. R2 = 0.59). Neither TDP-43 nor cerebrovascular disease global scales independently contributed to variability. Global scales of tau pathology (β-coefficient = 0.060, p = 0.016) and amyloid-β pathology (β-coefficient = 0.080, p < 0.001) independently predicted plasma p-tau217 when modeled together with co-pathologies, but only amyloid-β (β-coefficient = 0.33, p = 0.021) significantly predicted plasma p-tau181. While nucleus basalis of Meynert neuron count/mm2 was not associated with plasma p-tau levels, a lower locus coeruleus neuron count/mm2 was associated with higher plasma p-tau181 (R = -0.50, p = 0.007) and higher plasma p-tau217 (R = -0.55, p = 0.002). Cognitive scores (Adj. R2 = 0.25–0.32) were predicted by the global tau scale, but not by the global amyloid-β scale or plasma p-tau when modeled simultaneously. Conclusions Higher soluble plasma p-tau levels may be the result of an intersection between insoluble deposits of amyloid-β and tau accumulation in brain, and may be associated with locus coeruleus degeneration.Item Lewy Body Disease is a Contributor to Logopenic Progressive Aphasia Phenotype(Wiley, 2021) Buciuc, Marina; Whitwell, Jennifer L.; Kasanuki, Koji; Graff-Radford, Jonathan; Machulda, Mary M.; Duffy, Joseph R.; Strand, Edythe A.; Lowe, Val J.; Graff-Radford, Neill R.; Rush, Beth K.; Franczak, Malgorzata B.; Flanagan, Margaret E.; Baker, Matthew C.; Rademakers, Rosa; Ross, Owen A.; Ghetti, Bernardino F.; Parisi, Joseph E.; Raghunathan, Aditya; Reichard, R. Ross; Bigio, Eileen H.; Dickson, Dennis W.; Josephs, Keith A.; Pathology and Laboratory Medicine, School of MedicineObjective: The objective of this study was to describe clinical features, [18 F]-fluorodeoxyglucose (FDG)-positron emission tomography (PET) metabolism and digital pathology in patients with logopenic progressive aphasia (LPA) and pathologic diagnosis of diffuse Lewy body disease (DLBD) and compare to patients with LPA with other pathologies, as well as patients with classical features of probable dementia with Lewy bodies (pDLB). Methods: This is a clinicopathologic case-control study of 45 patients, including 20 prospectively recruited patients with LPA among whom 6 were diagnosed with LPA-DLBD. We analyzed clinical features and compared FDG-PET metabolism in LPA-DLBD to an independent group of patients with clinical pDLB and regional α-synuclein burden on digital pathology to a second independent group of autopsied patients with DLBD pathology and antemortem pDLB (DLB-DLBD). Results: All patients with LPA-DLBD were men. Neurological, speech, and neuropsychological characteristics were similar across LPA-DLBD, LPA-Alzheimer's disease (LPA-AD), and LPA-frontotemporal lobar degeneration (LPA-FTLD). Genetic screening of AD, DLBD, and FTLD linked genes were negative with the exception of APOE ε4 allele present in 83% of LPA-DLBD patients. Seventy-five percent of the patients with LPA-DLBD showed a parietal-dominant pattern of hy pometabolism; LPA-FTLD - temporal-dominant pattern, whereas LPA-AD showed heterogeneous patterns of hypometabolism. LPA-DLBD had more asymmetrical hypometabolism affecting frontal lobes, with relatively spared occipital lobe in the nondominantly affected hemisphere, compared to pDLB. LPA-DLBD had minimal atrophy on gross brain examination, higher cortical Lewy body counts, and higher α-synuclein burden in the middle frontal and inferior parietal cortices compared to DLB-DLBD. Interpretation: Whereas AD is the most frequent underlying pathology of LPA, DLBD can also be present and may contribute to the LPA phenotype possibly due to α-synuclein-associated functional impairment of the dominant parietal lobe.Item Longitudinal Clinical, Neuropsychological, and Neuroimaging Characterization of a Kindred with a 12-Octapeptide Repeat Insertion in PRNP: The Next Generation(Taylor & Francis, 2020-08) Townley, Ryan A.; Polsinelli, Angelina J.; Fields, Julie A.; Machulda, Mary M.; Jones, David T.; Graff-Radford, Jonathan; Kantarci, Kejal M.; Lowe, Val J.; Rademakers, Rosa V.; Baker, Matt C.; Kumar, Neeraj; Boeve, Bradley F.; Neurology, School of MedicineBackground: Highly penetrant inherited mutations in the prion protein gene (PRNP) offer a window to study the pathobiology of prion disorders. Method: Clinical, neuropsychological, and neuroimaging characterization of a kindred. Results: Three of four mutation carriers have progressed to a frontotemporal dementia phenotype. Declines in neuropsychological function coincided with changes in FDG-PET at the identified onset of cognitive impairment. Conclusions and relevance: Gene silencing treatments are on the horizon and when they become available, early detection will be crucial. Longitudinal studies involving familial mutation kindreds can offer important insights into the initial neuropsychological and neuroimaging changes necessary for early detection.Item New Insights into Atypical Alzheimer’s Disease in the Era of Biomarkers(Elsevier, 2021) Graff-Radford, Jonathan; Yong, Keir X.X.; Apostolova, Liana G.; Bouwman, Femke H.; Carrillo, Maria; Dickerson, Bradford C.; Rabinovici, Gil D.; Schott, Jonathan M.; Jones, David T.; Murray, Melissa E.; Neurology, School of MedicineMost patients with Alzheimer's disease present with amnestic problems; however, a substantial proportion, over-represented in young-onset cases, have atypical phenotypes including predominant visual, language, executive, behavioural, or motor dysfunction. In the past, these individuals often received a late diagnosis; however, availability of CSF and PET biomarkers of Alzheimer's disease pathologies and incorporation of atypical forms of Alzheimer's disease into new diagnostic criteria increasingly allows them to be more confidently diagnosed early in their illness. This early diagnosis in turn allows patients to be offered tailored information, appropriate care and support, and individualised treatment plans. These advances will provide improved access to clinical trials, which often exclude atypical phenotypes. Research into atypical Alzheimer's disease has revealed previously unrecognised neuropathological heterogeneity across the Alzheimer's disease spectrum. Neuroimaging, genetic, biomarker, and basic science studies are providing key insights into the factors that might drive selective vulnerability of differing brain networks, with potential mechanistic implications for understanding typical late-onset Alzheimer's disease.Item Performance of plasma phosphorylated tau 181 and 217 in the community(Springer Nature, 2022) Mielke, Michelle M.; Dage, Jeffrey L.; Frank, Ryan D.; Algeciras-Schimnich, Alicia; Knopman, David S.; Lowe, Val J.; Bu, Guojun; Vemuri, Prashanthi; Graff-Radford, Jonathan; Jack, Clifford R., Jr.; Petersen, Ronald C.; Neurology, School of MedicinePlasma phosphorylated tau 181 (P-tau181) and 217 (P-tau217) are indicators of both amyloid and tau pathology in clinical settings, but their performance in heterogeneous community-based populations is unclear. We examined P-tau181 and P-tau217 (n = 1,329, aged 30-98 years), in the population-based Mayo Clinic Study of Aging. Continuous, unadjusted plasma P-tau181 and P-tau217 predicted abnormal amyloid positron-emission tomography (PET) (area under the receiver operating characteristic curve (AUROC) = 0.81-0.86) and tau PET entorhinal cortex (AUROC > 0.80), but was less predictive of a tau PET temporal region of interest (AUROC < 0.70). Multiple comorbidities were associated with higher plasma P-tau181 and P-tau217 levels; the difference between participants with and without chronic kidney disease (CKD) was similar to the difference between participants with and without elevated brain amyloid. The exclusion of participants with CKD and other comorbidities affected the establishment of a normal reference range and cutpoints. Understanding the effect of comorbidities on P-tau181 and P-tau217 levels is important for their future interpretation in the context of clinical screening, diagnosis or prognosis at the population level.