Where Alzheimer's starts and how it spreads

A new study involving 96 older adults initially free of dementia at the time of enrollment, of whom 12 subsequently developed mild Alzheimer’s, has clarified three fundamental issues about Alzheimer's: where it starts, why it starts there, and how it spreads.

Specifically, it begins in the lateral entorhinal cortex (LEC), a gateway to the hippocampus. Over time, Alzheimer's spreads from the LEC directly to other areas of the cerebral cortex, in particular the parietal cortex. It’s thought that it spreads by compromising the function of neurons in the LEC, which then compromises the integrity of neurons in adjoining areas.

Mouse models comparing the effects of elevated levels of tau in the LEC with elevated levels of APP, and with elevated levels of both, found that LEC dysfunction occurred only in the mice with high levels of both tau and APP. The LEC normally accumulates tau, making it more vulnerable to the accumulation of APP.

http://www.eurekalert.org/pub_releases/2013-12/cumc-ssw121713.php

[3582] Khan, U. A., Liu L., Provenzano F. A., Berman D. E., Profaci C. P., Sloan R., et al.
(2014).  Molecular drivers and cortical spread of lateral entorhinal cortex dysfunction in preclinical Alzheimer's disease.
Nature Neuroscience. 17(2), 304 - 311.

Related News

Mild cognitive impairment (

A large study using data from the famous Framingham Heart Study has compared changes in dementia onset over the last three decades. The study found that over time the age of onset has increased while the length of time spent with dementia has decreased.

Data from more than 17,000 healthy people aged 50 and over has revealed that the more regularly participants engaged with word puzzles, the better they performed on tasks assessing attention, reasoning and memory.

Unplanned hospitalizations accelerate cognitive decline in older adults

Data from the Rush Memory and Aging Project has found that emergency and urgent hospitalizations are associated with an increased rate of cognitive decline in older adults.

A Finnish study involving 338 older adults (average age 66) has found that greater muscle strength is associated with better cognitive function.

Data from over 11,500 participants in the Atherosclerosis Risk in Communities (ARIC) cohort has found evidence that orthostatic hypotension in middle age may increase the risk of cognitive impairment and dementia 20 years later.

A review of 39 studies investigating the effect of exercise on cognition in older adults (50+) confirms that physical exercise does indeed improve cognitive function in the over 50s, regardless of their cognitive status.

A Canadian study involving 40 older adults (59-81), none of whom were aware of any major memory problems, has found that those scoring below 26 on the Montreal Cognitive Assessment (MoCA) dementia screening test also showed shrinking of the anterolateral

A study involving 35 adults with

In Australia, it has beens estimated that 9% of people aged over 65, and 30% of those aged over 85 have dementia. However, these estimates are largely based on older data from other countries, or small local samples.

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news