Journal of Alzheimer's disease : JAD
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The rs75932628-T variant of the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has recently been identified as a rare risk factor for late-onset Alzheimer's disease (AD). In this study we examined the association between TREM2 exon 2 variants and early-onset AD in a sample of Caucasian subjects of French origin including 726 patients with age of onset ≤65 years and 783 controls. Only the rs75932628-T variant (predicted to cause an R47H substitution) conferred a significant risk for early-onset AD (OR, 4.07; 95% CI, 1.3 to 16.9; p = 0.009). These results confirm the association between this variant and AD and underline its involvement in early-onset cases.
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Biomarkers for Alzheimer's disease (AD) based on non-invasive methods are highly desirable for diagnosis, disease progression, and monitoring therapeutics. We aimed to study the use of hippocampal volume, entorhinal cortex (ERC) thickness, and whole brain volume (WBV) as predictors of cognitive change in patients with AD. 120 AD subjects, 106 mild cognitive impairment (MCI), and 99 non demented controls (NDC) from the multi-center pan-European AddNeuroMed study underwent MRI scanning at baseline and clinical evaluations at quarterly follow-up up to 1 year. The rate of cognitive decline was estimated using cognitive outcomes, Mini-Mental State Examination (MMSE) and Alzheimer disease assessment scale-cognitive (ADAS-cog) by fitting a random intercept and slope model. ⋯ Therefore, the rate of atrophy in this structure is expected to be higher since neurodegeneration begins earlier. Focusing on structural analyses that predict decline can identify those individuals at greatest risk for future cognitive loss. This may have potential for increasing the efficacy of early intervention.
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Microglial markers are elevated in the prodromal phase of Alzheimer's disease and vascular dementia.
Microglia manage immunosurveillance and mediate inflammation, both suggested to be important in Alzheimer's disease (AD). The aim of this study was to investigate if microglial markers could differentiate, firstly between AD and controls, and secondly between stable mild cognitive impairment (MCI) and those progressing to AD and vascular dementia (VaD). Furthermore, we investigated if these markers were sufficiently stable to be used in clinical trials. ⋯ In addition, YKL-40 and sCD14 were very stable in AD patients with good correlation between time-points (r = 0.94, p = 3.4 × 10-25; r = 0.77, p = 2.0 × 10-11) and the cortical damage marker T-tau. Thus, microglial markers are stable and may be used as safety markers for monitoring CNS inflammation and microglia activation in clinical trials. Moreover, YKL-40 differentiates between AD and controls and between stable MCI to AD and those that convert to AD and VaD.
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New diagnostic criteria for Alzheimer's disease (AD) stress the role of in vivo biomarkers. Neurophysiological markers are usually not considered as such criteria, although theoretical and practical reasons would justify them. In order to assess the value of neurophysiology as an AD biomarker, whole-head magnetoencephalographic (MEG) resting state recordings were obtained from 35 AD patients, 23 mild cognitive impairment (MCI) patients, and 24 healthy controls. ⋯ More importantly, the localization of DCD values is in line with functional imaging markers of AD. However, MEG delta mapping is a totally non-invasive technique that directly measures neural activity. We propose that individuals with enhanced DCD in posterior parietal and precuneus cortices are at risk of progression to full dementia.
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Previous studies analyzed the ability of hippocampal volumes (HV) to differentiate Alzheimer's disease (AD) from frontotemporal dementia (FTD). However, these studies did not include patients selected according to clinico-biological criteria, using pathophysiological biomarkers. ⋯ When considered alone, measures of HV are not good markers to differentiate AD from bvFTD. Hippocampal sclerosis associated with FTD may explain the high degree of overlap in nHV between both groups.