Localized accumulation of tau without amyloid-beta in aged brains measured with [11C]PBB3 and [11C]PiB positron emission tomography

Objective Different regional specificity in tau accumulation is well known in Alzheimer’s disease (AD) brains. However, little is known about such distribution in aging brains and mild cognitive impairment (MCI) brains.Methods Cognitive functions and regional accumulation of tau and amyloid (A) were evaluated in 13 healthy controls (HCs), 3 patients with MCI, and 4 AD patients. Tau and A accumulation was semi-quantitatively measured with positron emission tomography (PET) using [11C]pyridinyl-butadienyl-benzothiazole 3 (PBB3) and [11C]Pittsburgh compound-B (PiB).Results Age-dependent accumulation of tau was found in all predetermined regions characteristic of AD, especially in the parahippocampal gyrus, lateral temporal cortex, frontal cortex, and posterior cingulate gyrus, where age-dependency was statistically significant. In contrast, age-dependency in accumulation of A was not observed in most regions assessed in HC. Moreover, the accumulation of tau in regions characteristic of AD in MCI patients were higher than that in HC, whereas tau accumulation was highest and statistically significant in AD patients. Unlike HC, the accumulation of tau was accompanied by that of Ain patients with MCI and AD. Conclusion Mild and age-dependent accumulation of tau without A was found in AD-related areas in aging brains. Considering age as a major risk for AD, higher accumulation of tau may trigger the neurodegenerative process of AD

Amyloid-Negative Dementia in the Elderly is Associated with High Accumulation of Tau in the Temporal Lobes

Background:We previously reported that among cases clinically diagnosed with Alzheimer’s disease, the proportion of amyloid beta (Aβ) -negative caseincreases in the elderly population. Tauopathy including Argyrophilic Grain Disease (AGD) and Neurofibrillary Tangle-Predominant Dementia(NFTPD), may be the leading causes of such dementia.Objective:To evaluate the involvement of tau, we studied tau accumulation in Amyloid-Negative Dementia Cases in the Elderly (ANDE) with PositronEmission Tomography (PET).Methods:Seven cases with slowly progressive dementia who were older than 80 years and were negative for Aβ were studied. In one case, autopsy obtained2 years after the PET examination revealed neurofibrillary tangles limited around the parahippocampal gyrus. Four cases showed strong lateralityin magnetic resonance imaging atrophy (clinical AGD), while the other three cases had no significant laterality in atrophy (clinical NFTPD). AgecorrectedPET data of healthy controls (HC; n = 12) were used as control. Tau accumulation was evaluated with [11C]PBB3-PET.Results:High accumulation was found in the lateral temporal cortex in ANDE. In autopsy case, scattered neurofibrillary tangles were found in theparahippocampal gyrus. In addition, there was a very high accumulation of PBB3 in the large area of bilateral parietal lobes, although nocorresponding tau component was found in the autopsied case.Conclusion:Relatively high burden of tau deposition was commonly observed in the lateral temporal cortex and parietal cortex of ANDE, part of which mayexplain dementia in these subjects. [11C]PBB3 may be useful in detecting tauopathy in ANDE

Prognostic value of end-of-induction PET response after first-line immunochemotherapy for follicular lymphoma (GALLIUM): secondary analysis of a randomised, phase 3 trial

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