Browsing by Author "Vandevrede, Lawren"

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    Head-to-head comparison between plasma p-tau217 and flortaucipir-PET in amyloid-positive patients with cognitive impairment
    (BMC, 2023-09-22) Mundada, Nidhi S.; Rojas, Julio C.; Vandevrede, Lawren; Thijssen, Elisabeth H.; Iaccarino, Leonardo; Okoye, Obiora C.; Shankar, Ranjani; Soleimani‑Meigooni, David N.; Lago, Argentina L.; Miller, Bruce L.; Teunissen, Charlotte E.; Heuer, Hillary; Rosen, Howie J.; Dage, Jeffrey L.; Jagust, William J.; Rabinovici, Gil D.; Boxer, Adam L.; La Joie, Renaud; Neurology, School of Medicine
    Background: Plasma phosphorylated tau (p-tau) has emerged as a promising biomarker for Alzheimer's disease (AD). Studies have reported strong associations between p-tau and tau-PET that are mainly driven by differences between amyloid-positive and amyloid-negative patients. However, the relationship between p-tau and tau-PET is less characterized within cognitively impaired patients with a biomarker-supported diagnosis of AD. We conducted a head-to-head comparison between plasma p-tau217 and tau-PET in patients at the clinical stage of AD and further assessed their relationships with demographic, clinical, and biomarker variables. Methods: We retrospectively included 87 amyloid-positive patients diagnosed with MCI or dementia due to AD who underwent structural MRI, amyloid-PET (11C-PIB), tau-PET (18F-flortaucipir, FTP), and blood draw assessments within 1 year (age = 66 ± 10, 48% female). Amyloid-PET was quantified in Centiloids (CL) while cortical tau-PET binding was measured using standardized uptake value ratios (SUVRs) referenced against inferior cerebellar cortex. Plasma p-tau217 concentrations were measured using an electrochemiluminescence-based assay on the Meso Scale Discovery platform. MRI-derived cortical volume was quantified with FreeSurfer. Mini-Mental State Examination (MMSE) scores were available at baseline (n = 85) and follow-up visits (n = 28; 1.5 ± 0.7 years). Results: Plasma p-tau217 and cortical FTP-SUVR were correlated (r = 0.61, p < .001), especially in temporo-parietal and dorsolateral frontal cortices. Both higher p-tau217 and FTP-SUVR values were associated with younger age, female sex, and lower cortical volume, but not with APOE-ε4 carriership. PIB-PET Centiloids were weakly correlated with FTP-SUVR (r = 0.26, p = 0.02), but not with p-tau217 (r = 0.10, p = 0.36). Regional PET-plasma associations varied with amyloid burden, with p-tau217 being more strongly associated with tau-PET in temporal cortex among patients with moderate amyloid-PET burden, and with tau-PET in primary cortices among patients with high amyloid-PET burden. Higher p-tau217 and FTP-SUVR values were independently associated with lower MMSE scores cross-sectionally, while only baseline FTP-SUVR predicted longitudinal MMSE decline when both biomarkers were included in the same model. Conclusion: Plasma p-tau217 and tau-PET are strongly correlated in amyloid-PET-positive patients with MCI or dementia due to AD, and they exhibited comparable patterns of associations with demographic variables and with markers of downstream neurodegeneration.
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    Recommendations for clinical implementation of blood-based biomarkers for Alzheimer's disease
    (Wiley, 2024) Mielke, Michelle M.; Anderson, Matthew; Ashford, J. Wesson; Jeromin, Andreas; Lin, Pei-Jung; Rosen, Allyson; Tyrone, Jamie; Vandevrede, Lawren; Willis, Deanna R.; Hansson, Oskar; Khachaturian, Ara S.; Schindler, Suzanne E.; Weiss, Joan; Batrla, Richard; Bozeat, Sasha; Dwyer, John R.; Holzapfel, Drew; Jones, Daryl Rhys; Murray, James F.; Partrick, Katherine A.; Scholler, Emily; Vradenburg, George; Young, Dylan; Braunstein, Joel B.; Burnham, Samantha C.; de Oliveira, Fabricio Ferreira; Hu, Yan Helen; Mattke, Soeren; Merali, Zul; Monane, Mark; Sabbagh, Marwan Noel; Shobin, Eli; Weiner, Michael; Udeh-Momoh, Chinedu T.; Medicine, School of Medicine
    Blood-based biomarkers (BBM) for Alzheimer's disease (AD) are being increasingly used in clinical practice to support an AD diagnosis. In contrast to traditional diagnostic modalities, such as amyloid positron emission tomography and cerebrospinal fluid biomarkers, BBMs offer a more accessible and lower cost alternative for AD biomarker testing. Their unique scalability addresses the anticipated surge in demand for biomarker testing with the emergence of disease-modifying treatments (DMTs) that require confirmation of amyloid pathology. To facilitate the uptake of BBMs in clinical practice, The Global CEO Initiative on Alzheimer's Disease convened a BBM Workgroup to provide recommendations for two clinical implementational pathways for BBMs: one for current use for triaging and another for future use to confirm amyloid pathology. These pathways provide a standardized diagnostic approach with guidance on interpreting BBM test results. Integrating BBMs into clinical practice will simplify the diagnostic process and facilitate timely access to DMTs for eligible patients.