| 6-Jan-2005 - Further Evidence
of GFAP as a Useful Marker is Offered in New Study by NIOSH, Partner Researchers
New findings from a study by the National Institute for
Occupational Safety and Health (NIOSH) and the Pacific Health Research
Institute provide further evidence that a protein in the human brain,
glial fibrillary acidic protein (GFAP), can serve as a valuable marker
to identify types of brain damage associated with dementia that might
not be identified through traditional histopathology.
The findings are published in the Journal of Alzheimer’s
Disease, Vol. 6, No. 6. An abstract is available online at www.j-alz.com/issues/6/vol6-6.html.
The study is part of NIOSH’s program of ongoing health-effects research,
including work on the development and use of new biomarkers to advance
the prevention of work-related neurological disorders.
The prevalence of dementia among the elderly is of growing
concern in the U.S. Multiple forms of dementia exist. However, there often
is no clear way to distinguish among the various forms. The causes of
dementia are also multiple and complex, and in many cases cannot be confirmed
until a neuropathological examination is conducted during autopsy.
When such an examination is performed, it often infers
the cause of dementia from the presence of specific neuroanatomical markers
such as Lewy bodies in the case of Parkinson’s-related dementia,
or neurofibrillary plaques and tangles in the case of Alzheimer’s
disease. This approach can be limited by:
* The lack of unique neuropathological markers for the
various types of dementia,
* The co-expression of existing markers, or
* The lack of markers in some individuals who show clear
signs of dementia, or even the presence of these markers in the brains
of individuals who did not show any signs of dementia.
NIOSH researchers and their partners have been investigating
the question of whether various occupational exposures are associated
with a risk of neurological disease, using a study population of Japanese-American
men who were born between 1900 and 1919. In this study, levels of GFAP,
a sensitive marker of neural damage, were measured in brain tissue samples
of deceased men who had been diagnosed with dementia, and of deceased
men who had not been diagnosed with dementia. This protein, produced by
a type of glial cell thought to support neurons in the brain, has been
shown to increase in regions of neural damage, regardless of the cause
of the damage. Thus, it is a non-specific yet sensitive marker of neural
damage.
The investigators found increased levels of GFAP in several
brain regions among individuals diagnosed with Alzheimer’s disease,
vascular mediated dementia, and mixed dementia, compared with individuals
not diagnosed with those disorders. Further, the researchers showed that
higher GFAP levels were associated with a lower performance on a test
of cognitive function. This association remained significant even when
specific neuropathological markers of dementia were accounted for.
Full Release - http://www.cdc.gov/niosh/updates/upd-01-06-05.html
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