Current Alzheimer research
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Alzheimer's disease (AD) is the major cause of dementia in the world. Although the entorhinal cortex and hippocampal complex are best known as the sites of early pathology in AD, increasing evidence shows that the eye, particularly the retina, is also affected. The AD-related changes in the retina are associated with degeneration and loss of neurons, reduction of the retinal nerve fibres, increase in optic disc cupping, retinal vascular tortusity and thinning, and visual functional impairment. ⋯ In addition to the changes in the eyes of AD patients, similar mechanisms of neurodegeneration in the brain have also been demonstrated in the eye. Targeting AD-liked changes in the retina has been recently shown to be effective in the reduction of retinal neuronal degeneration and loss in eye diseases. This review will cover recent findings on retinal degeneration in AD, pathological similarities between AD and eye diseases, and highlight the potential of modern technologies for the detection of prospective biomarkers in the eye in early AD.
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Randomized Controlled Trial Multicenter Study
Safety of lumbar puncture procedures in patients with Alzheimer's disease.
Changes in cerebrospinal fluid (CSF) biomarkers are representative of biochemical changes in the brain. Collection of CSF by lumbar puncture (LP) is essential for biomarker analysis, which is important for research in neurodegenerative disorders. However, LP for research purposes has been controversial due to a reported high incidence of severe LP headache when using standard 18g or 20g Quincke needles with a beveled cutting tip. ⋯ A 24g Sprotte atraumatic needle was used to collect CSF at baseline and at Week 13 from 63 older patients with mild to moderate Alzheimer's disease. There was a < 2% LP headache incidence, and a favorable safety profile was reported. In conclusion, LP performed with a 24g Sprotte atraumatic needle (blunt, "bullet" tip) was a well tolerated procedure, with good acceptability.
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Accumulation of beta-amyloid peptide (Abeta) in the brain is a primary influence driving Alzheimer's disease (AD) pathogenesis. The disease process, including formation of neurofibrillary tangles containing tau protein, is proposed to result from an imbalance between production and clearance of Abeta. A major therapeutic strategy for AD should be to decrease deposition of Abeta by the inhibition of its production and the facilitation of its degradation. Hence, the primary aim of this study was to investigate effects of GEPT, a combination of herbal extracts, on Abeta levels, beta- and gamma-secretases substrate (BACE1 and PS1, respectively) associated with production of Abeta, and insulin-degrading enzyme (IDE) and neprilysin (NEP) related to degradation of Abeta in the brain. ⋯ The combination of GEPT extracts can reduce levels of endogenous Abeta peptide in APPV717I transgenic mice through the inhibition of PS1 activity rather than BACE1 and the promotion of IDE and NEP activity. Lower-expression of PS1 and over-expression of IDE or NEP may be helpful in potentially lowering brain Abeta levels in subjects with AD, and hence GEPT appears to offer potential that should be explored in AD.
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Randomized Controlled Trial Multicenter Study
Memantine treatment in patients with mild to moderate Alzheimer's disease already receiving a cholinesterase inhibitor: a randomized, double-blind, placebo-controlled trial.
To evaluate the efficacy and safety of memantine in patients with mild to moderate Alzheimer's disease (AD) receiving cholinesterase inhibitor (ChEI) treatment. ⋯ In this trial, memantine did not show an advantage over placebo based on protocol-specified primary or secondary analyses in patients with mild to moderate AD on stable ChEI regimens. There were no significant differences in tolerability and safety between the memantine- and placebo groups.
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Insulin modulates cognition and other aspects of normal brain function. Insulin resistance is characterized by chronic peripheral insulin elevations, and it is accompanied by reduced brain insulin levels and insulin activity. Obesity, type 2 diabetes mellitus and hypertension are strongly associated with insulin resistance. ⋯ We have shown that raising plasma insulin in humans to levels that characterize patients with insulin resistance increases the levels of Abeta and inflammatory agents in brain. These convergent effects may impair memory and induce AD pathology. Therapeutic strategies focused on preventing or correcting insulin abnormalities may thus benefit a subset of adults with age-related memory impairment and AD.