Abstract: It is unclear whether the distribution of tau pathology differs between cases with early-onset familial Alzheimer’s disease (AD) and sporadic AD. We present positron emission tomography (PET) data from a young patient with a presenilin-1 mutation (Thr116Asn). 18 F-flutemetamol PET showed a distribution of amyloid-β fibrils similar to sporadic AD. However, the pattern of tau pathology, revealed using 18 F-AV1451 PET, showed higher uptake in posterior cingulate, precuneus, parietal and occipital cortices compared to late-onset sporadic AD. Further, the tau pathology, but not amyloid pathology, exhibited a very clear inverse relationship with 18 F-fluorodeoxyglucose-metabolism, indicating neuronal hypometabolism in regions affected…by tau aggregates.
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Keywords: Alzheimer’s disease, positron-emission tomography, presenilins, tau proteins
Abstract: Background: Recent studies in Huntington's disease (HD) mouse models and patients suggest that hippocampal neurons and their cholinergic afferents are involved in the cognitive deficits seen in the disease. Nerve growth factor (NGF) is an essential regulator of cholinergic neuronal survival and neurotransmission. Objective: We asked whether NGF might be involved in HD and if intra-cerebroventricular infusion of NGF can rescue hippocampal cholinergic neuronal markers, restore neurogenesis, and improve the spatial working memory in R6/1 mouse model of HD. Methods: We quantified NGF protein level by enzyme-linked immunosorbent assay (ELISA), intracerebroventricularly infused NGF, assessed cholinergic neuronal markers by Western blotting…and quantitative RT-PCR, evaluated neurogenesis by immunohistochemistry, and studied spatial working memory using radial maze. Results: By quantifying NGF protein in the hippocampus of the R6/1 mice at different ages, we found progressive decreases in NGF protein levels. We then increased NGF levels in the R6/1 mice through intra-cerebroventricular infusion. We observed elevations of the cholinergic neurochemical markers vesicular acetylcholine transporter (VAChT) and choline acetyltransferase (ChAT) in the hippocampus and in the septal region, which contain the cell bodies of basal forebrain cholinergic neurons (BFCNs), but not in the striatum that harbors cholinergic interneurons. Finally, we found that NGF infusion also restored hippocampal neurogenesis and improved spatial working memory. Conclusions: Our results suggest that intracerebral injections of NGF might be a valuable therapy against cognitive symptoms in HD and should be further studied in HD animal models and patients.
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