Neurology Central

New details emerge on Alzheimer’s and dementia in the aged brain

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A research team hailing from the Allen Institute for Brain Science, UW Medicine and Kaiser Permanente Washington Health Research Institute (all WA, USA) have carried out analysis on 107 human brains to better understand Alzheimer’s and dementia in aging populations. Their findings could impact how dementia and Alzheimer’s are treated in the future.

The aim of this research was to establish if correlations previously identified between cognitive status, gene expression and brain pathologies were still present in an aged cohort. Researchers from this team combined traditional and quantitative measures to investigate the relationships between gene expression and age-related neurodegeneration. The brains used were from > 85-year-olds, which is relatively uncommon in current research. “Several studies exist that compare expression in donor brains aged 60–85 years, but few in the more aged cohort we were able to study here,” explained Jeremy Miller, lead author on the publication and Senior Scientist at the Allen Institute for Brain Science. “We found that the more aged brains still showed a correlation between cognitive decline and the Alzheimer’s-associated plaques and tangles, although the relationship was not as strong as in younger cohorts.”

The results also indicated a striking amount of variability in the aged brains, with some individuals even displaying a resistance to pathology. Although these discoveries revealed just how complex the effects of neurodegenerative diseases on much older brains are, one correlation was shown as constant. – decreased quality of RNA and incidences of dementia appeared to be related.

Miller concluded: “This variable is not necessarily related to any specific pathology or disease, but these results highlight the importance of properly controlling for RNA quality when studying the aged brain and indicate that degradation of genetic material may be an underappreciated feature of neurodegeneration or dementia.”

All data emerging from this research are available free of charge as part of the ‘Aging, Dementia and TBI’ Resource on Allen Brain Atlas Portal. “We want to promote a model of systematic, collaborative, multidimensional study of the diseased brain and open access to data and tools to facilitate discovery across the entire basic and biomedical research community,” assured Ed Lein, Investigator at the Allen Institute for Brain Science.

The researchers hope that the dataset will make a positive impact on future diagnostic approaches and therapeutic strategies in the field.

Sources:

  1. Allen Institute. Researchers reveal new details on aged brain, Alzheimer’s and dementia. Public Release: 21-Nov-2017. EurekAlert! (2017). https://www.eurekalert.org/pub_releases/2017-11/ai-rrn112017.php
  2. Miller JA, Guillozet-Bongaarts A, Gibbon LE et al. Neuropathological and transcriptomic characteristics of the aged brain. eLife 6, e31126 (2017).
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