Journal of Alzheimer's disease : JAD
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Significant differences exist in demographic characteristics between responders and non-responders in population-based studies on mental health and cognitive status, but much less is known regarding differences in the prevalence of dementia and cognitive dysfunction between them. Here we compared the prevalence of dementia and mild cognitive impairment between early responders of a mass brain function examination and delayed responders (non-responders of the mass brain function examination) in a survey of elderly Japanese citizens (≥65 years) to evaluate non-responder bias. All residents in an area of Nakajima, Japan, were considered as potential candidates (n = 783). ⋯ Delayed responders (n = 320) were significantly older and less educated than the early responders (n = 307). The delayed responders also exhibited a higher frequency of dementia and mild cognitive impairment than the early responders, even when the groups were restricted to the age group 65-89 years. Our results suggest that population-based studies likely underestimate the prevalence of dementia and mild cognitive impairment, especially if the participation rate is low.
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The frequency and clinical and pathological characteristics associated with the Gly206Ala presenilin 1 (PSEN1) mutation in Puerto Rican and non-Puerto Rican Hispanics were evaluated at the University of Pennsylvania's Alzheimer's Disease Center. DNAs from all cohort subjects were genotyped for the Gly206Ala PSEN1 mutation. Carriers and non-carriers with neurodegenerative disease dementias were compared for demographic, clinical, psychometric, and biomarker variables. ⋯ Neuropathological examination in one subject revealed severe, widespread plaque and tangle pathology without other meaningful disease lesions. The PSEN1 Gly206Ala mutation is notably frequent in unrelated Puerto Rican immigrants with dementia in Philadelphia. Considered together with the increased prevalence and mortality of AD reported in Puerto Rico, these high rates may reflect hereditary risk concentrated in the island which warrants further study.
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Recent studies have suggested that memory circuits can be modulated by deep brain stimulation (DBS). This propriety might be used to slow down cognitive decline in patients suffering from Alzheimer's disease (AD). We conducted a prospective study to evaluate the feasibility and safety of DBS in AD patients with mild cognitive decline. ⋯ After one year of stimulation, the memory scores (MMSE, ADAS-Cog, Free and Cued Selective Reminding Test) were stabilized compared to baseline, and mesial temporal lobes metabolism increased. This pilot study provides new data about the safety of fornix DBS in the hypothalamus. However, it suggests that only a small proportion of AD patients might be interested in this approach and that the acceptance of DBS by AD patients was low, raising questions about the relevance of this approach to meet the expectations of these patients.
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Sortilin-related receptor with A-type repeats (SorLA, also known as LR11) has been implicated in Alzheimer's disease (AD). Thus, genetic studies associated SorLA gene variants with the risk of sporadic AD. Also, in vitro and in vivo studies showed that SorLA impairs processing of the amyloid-β protein precursor (AβPP) to amyloid-β. ⋯ We found that the loss of SorLA not only exacerbates early amyloid pathology but, at the same time, protects from cholinergic deficit and from early phospho-tau mislocalization. The results show that in the AD10 anti-NGF mouse model the AβPP processing-related aspects of neurodegeneration can be dissociated from those related to tau posttranslational processing and to cholinergic phenotypic maintenance by modulation of SorLA expression. We suggest that SorLA regulates different aspects of neurodegeneration in a complex way, supporting the hypothesis that SorLA expression might be critical not only for amyloid-related pathology but also for other cellular processes altered in AD.
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To date, the exact pathogenesis of dementia is still unknown. The most frequently hypothesized initiating factor is an accumulation of the protein amyloid-β in the brain, which has been associated with dementia of the Alzheimer type. Another potentially important initiating factor is a disrupted blood-brain barrier. ⋯ Although amyloid-β and blood-brain barrier dysfunction have both been associated with one particular type of dementia (Alzheimer's disease and vascular dementia, respectively), they co-exist in most demented patients. In fact, increasing evidence indicates that amyloid-β and blood-brain barrier disruption may interact and facilitate each other in their effect on neurodegeneration. The present systematic analysis describes the available evidence for a significant interplay between amyloid-β and blood-brain barrier function in dementia.