%0 Journal Article %J J Alzheimers Dis %D 2018 %T Pramlintide: The Effects of a Single Drug Injection on Blood Phosphatidylcholine Profile for Alzheimer's Disease. %A Tao, Qiushan %A Zhu, Haihao %A Chen, Xi %A Stern, Robert A %A Kowall, Neil %A Au, Rhoda %A Blusztajn, Jan Krzysztof %A Qiu, Wei Qiao %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Amyloid beta-Peptides %K Biomarkers %K Cognitive Dysfunction %K Female %K Humans %K Islet Amyloid Polypeptide %K Logistic Models %K Male %K Middle Aged %K Phosphatidylcholines %K ROC Curve %K tau Proteins %X

Studies suggest that a single injection of pramlintide, an amylin analog, induces changes in Alzheimer's disease (AD) biomarkers in the blood of AD mouse models and AD patients. The aim of this study was to examine whether a pramlintide challenge combined with a phosphatidylcholine (PC) profile diagnoses of AD and mild cognitive impairment (MCI) better than PC alone. Non-diabetic subjects with cognitive status were administered a single subcutaneous injection of 60 mcg of pramlintide under fasting condition. A total of 71 PCs, amyloid-β peptide (Aβ), and total tau (t-tau) in plasma at different time points were measured and treated as individual variables. A single injection of pramlintide altered the levels of 7 PCs in the blood, while a pramlintide injection plus food modulated the levels of 10 PCs in the blood (p < 0.05). The levels of 2 PCs in MCI and 12 PCs in AD in the pramlintide challenge were significantly lower than the ones in controls. We found that while some PCs were associated with only Aβ levels, other PCs were associated with both Aβ and t-tau levels. A receiver operating characteristic analysis of the PCs was combined with the Aβ and t-tau data to produce an area under the curve predictive value of 0.9799 between MCI subjects and controls, 0.9794 between AD subjects and controls, and 0.9490 between AD and MCI subjects. A combination of AD biomarkers and a group of PCs post a pramlintide challenge may provide a valuable diagnostic and prognostic test for AD and MCI.

%B J Alzheimers Dis %V 62 %P 597-609 %8 2018 %G eng %N 2 %1 http://www.ncbi.nlm.nih.gov/pubmed/29480193?dopt=Abstract %R 10.3233/JAD-170948 %0 Journal Article %J J Alzheimers Dis %D 2017 %T Modeling the Relationships Among Late-Life Body Mass Index, Cerebrovascular Disease, and Alzheimer's Disease Neuropathology in an Autopsy Sample of 1,421 Subjects from the National Alzheimer's Coordinating Center Data Set. %A Alosco, Michael L %A Duskin, Jonathan %A Besser, Lilah M %A Martin, Brett %A Chaisson, Christine E %A Gunstad, John %A Kowall, Neil W %A McKee, Ann C %A Stern, Robert A %A Tripodis, Yorghos %K Aged %K Aged, 80 and over %K Alzheimer Disease %K Autopsy %K Body Mass Index %K Cerebrovascular Disorders %K Datasets as Topic %K Female %K Humans %K Male %K National Institute on Aging (U.S.) %K Neuropathology %K Neuropsychological Tests %K Retrospective Studies %K United States %X

The relationship between late-life body mass index (BMI) and Alzheimer's disease (AD) is poorly understood due to the lack of research in samples with autopsy-confirmed AD neuropathology (ADNP). The role of cerebrovascular disease (CVD) in the interplay between late-life BMI and ADNP is unclear. We conducted a retrospective longitudinal investigation and used joint modeling of linear mixed effects to investigate causal relationships among repeated antemortem BMI measurements, CVD (quantified neuropathologically), and ADNP in an autopsy sample of subjects across the AD clinical continuum. The sample included 1,421 subjects from the National Alzheimer's Coordinating Center's Uniform Data Set and Neuropathology Data Set with diagnoses of normal cognition (NC; n = 234), mild cognitive impairment (MCI; n = 201), or AD dementia (n = 986). ADNP was defined as moderate to frequent neuritic plaques and Braak stageIII-VI. Ischemic Injury Scale (IIS) operationalized CVD. Joint modeling examined relationships among BMI, IIS, and ADNP in the overall sample and stratified by initial visit Clinical Dementia Rating score. Subject-specific random intercept for BMI was the predictor for ADNP due to minimal BMI change (p = 0.3028). Analyses controlling for demographic variables and APOE ɛ4 showed lower late-life BMI predicted increased odds of ADNP in the overall sample (p < 0.001), and in subjects with CDR of 0 (p = 0.0021) and 0.5 (p = 0.0012), but not ≥1.0 (p = 0.2012). Although higher IIS predicted greater odds of ADNP (p < 0.0001), BMI did not predict IIS (p = 0.2814). The current findings confirm lower late-life BMI confers increased odds for ADNP. Lower late-life BMI may be a preclinical indicator of underlying ADNP.

%B J Alzheimers Dis %V 57 %P 953-968 %8 2017 %G eng %N 3 %1 http://www.ncbi.nlm.nih.gov/pubmed/28304301?dopt=Abstract %R 10.3233/JAD-161205 %0 Journal Article %J J Alzheimers Dis %D 2016 %T Preliminary Study of Plasma Exosomal Tau as a Potential Biomarker for Chronic Traumatic Encephalopathy. %A Stern, Robert A %A Tripodis, Yorghos %A Baugh, Christine M %A Fritts, Nathan G %A Martin, Brett M %A Chaisson, Christine %A Cantu, Robert C %A Joyce, James A %A Shah, Sahil %A Ikezu, Tsuneya %A Zhang, Jing %A Gercel-Taylor, Cicek %A Taylor, Douglas D %K Adult %K Aged %K Analysis of Variance %K Case-Control Studies %K Chronic Traumatic Encephalopathy %K Extracellular Vesicles %K Humans %K Male %K Middle Aged %K Plasma %K tau Proteins %X

BACKGROUND: Chronic traumatic encephalopathy (CTE) is a tauopathy associated with prior exposure to repetitive head impacts, such as those incurred through American football and other collision sports. Diagnosis is made through neuropathological examination. Many of the clinical features of CTE are common in the general population, with and without a history of head impact exposure, making clinical diagnosis difficult. As is now common in the diagnosis of other neurodegenerative disorders, such as Alzheimer's disease, there is a need for methods to diagnose CTE during life through objective biomarkers.

OBJECTIVE: The aim of this study was to examine tau-positive exosomes in plasma as a potential CTE biomarker.

METHODS: Subjects were 78 former National Football League (NFL) players and 16 controls. Extracellular vesicles were isolated from plasma. Fluorescent nanoparticle tracking analysis was used to determine the number of vesicles staining positive for tau.

RESULTS: The NFL group had higher exosomal tau than the control group (p <  0.0001). Exosomal tau discriminated between the groups, with 82% sensitivity, 100% specificity, 100% positive predictive value, and 53% negative predictive value. Within the NFL group, higher exosomal tau was associated with worse performance on tests of memory (p = 0.0126) and psychomotor speed (p = 0.0093).

CONCLUSION: These preliminary findings suggest that exosomal tau in plasma may be an accurate, noninvasive CTE biomarker.

%B J Alzheimers Dis %V 51 %P 1099-109 %8 2016 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/26890775?dopt=Abstract %R 10.3233/JAD-151028