Alzheimer's Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Alzheimer's Disease, including details on diagnosis, memory loss, heredity, treatment, medication. | ||||||||
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TDP-43 immunoreactivity in hippocampal sclerosis and Alzheimer's disease.Amador-Ortiz C, Lin WL, Ahmed Z, Personett D, Davies P, Duara R, Graff-Radford NR, Hutton ML, Dickson DW Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, FL 32224, USA. OBJECTIVE: This study aimed to determine the frequency of frontotemporal lobar degeneration with ubiquitinated inclusions (FTLD-U) in the setting of hippocampal sclerosis (HpScl) and Alzheimer's disease (AD) using immunohistochemistry for TAR DNA binding protein 43 (TDP-43), a putative marker for FTLD-U. METHODS: Initially, 21 cases of HpScl associated with a variety of other pathological processes and 74 cases of AD were screened for FTLD-U with TDP-43 immunohistochemistry. A confirmation study was performed on 93 additional AD cases. Specificity of TDP-43 antibodies was assessed using double-immunolabeling confocal microscopy, immunoelectron microscopy, and biochemistry. RESULTS: TDP-43 immunoreactivity was detected in 71% of HpScl and 23% of AD cases. Double immunostaining of AD cases for TDP-43 and phospho-tau showed that the TDP-43-immunoreactive inclusions were usually distinct from neurofibrillary tangles. At the ultrastructural level, TDP-43 immunoreactivity in AD was associated with granular and filamentous cytosolic material and only occasionally associated with tau filaments. Western blots of AD cases showed a band that migrated at a higher molecular weight than normal TDP-43 that was not present in AD cases without TDP-43 immunoreactivity. INTERPRETATION: These results suggest that as many as 20% of AD cases and more than 70% of HpScl cases have pathology similar to that found in FTLD-U. Whether this represents concomitant FTLD-U or is analogous to colocalization of alpha-synuclein and tau in AD, reflecting a propensity for codeposition of abnormal protein conformers, remains to be determined. Published 3 May 2007 in Ann Neurol, 61(5): 435-45.
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