Dementia is a common illness with an incidence that is rising as the aged population increases. A multitude of neurodegenerative illnesses have an associated dementia, including corticobasal degeneration, Creutzfeldt–Jakob disease, Huntington’s disease, progressive supranuclear palsy, multiple system atrophy, Parkinson’s disease dementia, and amyotrophic lateral sclerosis, to name a few. In the past diagnostic criteria have relied on a overt spectrum of symptoms, however, the definite diagnosis remains a pathologic and tangible one.
As treatments become available and target specific molecular abnormalities, differentiating amongst the various primary dementias early is now crucial. Now, The Allen Institute for Brain Science has announced major updates to its online resources available at brain-map.org, including a new resource on Aging, Dementia and Traumatic Brain Injury (TBI) in collaboration with the University of Washington, and Group Health. The team state that the resource is the first of its kind to collect and share a variety of data modalities on a large sample of aged brains, complete with mental health histories and clinical diagnoses.
Previous studies show that brain imaging is routinely performed in the evaluation of dementias, with the use of structural imaging, such as computed tomography or magnetic resonance imaging recommended to assist in the diagnosis of dementia and to specifically rule out reversible, treatable causes. Different brain imaging techniques allow the examination of the structure, biochemistry, metabolic state, and functional capacity of the brain. All of the major neurodegenerative disorders have relatively specific imaging-markers that can be identified. It is widely known that new imaging techniques carry the hope of revolutionizing the diagnosis of neurodegenerative disease, with structural and functional imaging modalities contributing to the diagnosis and understanding of the different dementias. The current study is a detailed neuropathologic, molecular and transcriptomic characterization of aged brains of control and TBI/dementia exposure cases from a unique aged population-based cohort from the Adult Changes in Thought (ACT) study.
The current study samples come from the Adult Changes in Thought (ACT) study, a longitudinal research effort to collect data on thousands of aging adults, including detailed information on their health histories and cognitive abilities. The lab collected post-mortem samples from 107 brains aged 79 to 102, with tissue collected from the parietal cortex, temporal cortex, hippocampus and cortical white matter.
Results include quantitative image data to show the disease state of each sample, protein data related to those disease states, gene expression data and de-identified clinical data for each case. Data findings show that because the data is so complex, the online resource also includes a series of animated ‘snapshots,’ giving users a dynamic sampling of the ways they can question the data. The group state that this is the first resource of its kind to combine a variety of data types and a large sample size, making it a remarkably holistic view of the aged brain in all its complexity.
Researchers focused on examining the impact of mild to moderate TBI on the aged brain, comparing samples from patients with self-reported loss of consciousness incidents against meticulously matched controls. The lab stress that while they observed many other trends in these data, they did not uncover a distinctive genetic signature or pathologic biomarker in patients with TBI and loss of consciousness in this population study.
The team surmise that their new resource is an exciting addition to their suite of opensource resources. They go on to add that the global medical community will be able to mine the data and explore many facets of the aged brain, which they hope will accelerate discoveries about health and disease in aging. For the future the researchers state for the first time the global medical community will have access to this unique dataset, which will advance the study of brain aging and hopefully contribute to development of novel diagnostic and therapeutic strategies for neurodegenerative disease.