2-(4--(methylamino)phenyl)-6-hydroxybenzothiazole and Nerve-Degeneration

We investigated the extent to which decline in memory and working memory in beta-amyloid (Aβ) positive non-demented individuals was related to hippocampal atrophy and Aβ accumulation over 36 months. Cognitively normal older adults (CN) (n = 178) and adults with mild cognitive impairment (MCI) (n = 49) underwent positron emission tomography neuroimaging, magnetic resonance imaging, and cognitive assessments at baseline, 18- and 36-months. Relative to Aβ- CNs, Aβ+ CNs and Aβ+ MCIs showed greater rates of cognitive decline, Aβ accumulation, and hippocampal atrophy. Analysis of interrelationships between these Alzheimer's disease markers in Aβ+ CNs and MCIs indicated that rate of Aβ accumulation was associated with rate of hippocampal atrophy (β = -0.05, p = .037), which was in turn associated independently with rate of decline in memory (β = -0.03, p = .032). This suggests that Aβ accumulation precedes any neurodegeneration or clinical symptoms, and that the relationship between Aβ and cognitive decline is mediated by hippocampal atrophy.

Topics: Aged; Aged, 80 and over; Aging; Amyloid beta-Peptides; Aniline Compounds; Apolipoproteins E; Atrophy; Carbon Isotopes; Cognitive Dysfunction; Female; Hippocampus; Humans; Linear Models; Magnetic Resonance Imaging; Male; Memory Disorders; Memory, Short-Term; Middle Aged; Nerve Degeneration; Neuropsychological Tests; Positron-Emission Tomography; Thiazoles; Time Factors

To investigate whether global and regional beta-amyloid (Abeta) burden as measured with 11C Pittsburgh compound B (PIB) PET is associated with hippocampal atrophy characterized using MRI in healthy controls and patients with amnestic mild cognitive impairment (aMCI) or Alzheimer disease (AD).. Ninety-two elderly healthy controls, 32 subjects with aMCI, and 35 patients with AD were imaged using 11C-PIB PET and MRI. Hippocampal volume was measured and PIB standardized uptake value ratio was extracted after partial volume correction within 41 regions of interest. Global, regional, and voxel-based correlations between PIB and hippocampal volume were computed for each group.. In healthy control participants with elevated neocortex PIB retention, significant correlation was found between PIB retention in the inferior temporal region and hippocampal volume using both region-based and voxel-based approaches. No correlation was found in any other group.. The strong correlation between hippocampal atrophy and beta-amyloid (Abeta) burden in the Pittsburgh compound B-positive healthy control group suggests that Abeta deposition in the inferior temporal neocortex is related to hippocampal synaptic and neuronal degeneration.

Topics: Age Factors; Aged; Aged, 80 and over; Aging; Algorithms; Amyloid beta-Peptides; Aniline Compounds; Atrophy; Biomarkers; Brain Mapping; Carbon Radioisotopes; Cohort Studies; Disease Progression; Female; Hippocampus; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Neocortex; Nerve Degeneration; Plaque, Amyloid; Positron-Emission Tomography; Severity of Illness Index; Temporal Lobe; Thiazoles