EARLY ALZHEIMER-DISEASE-LIKE HISTOPATHOLOGY INCREASES IN FREQUENCY WITH AGE IN MICE TRANSGENIC FOR BETA-APP751

beta-Amyloid deposition and neurofibrillary tangle formation are two h istopathological features of Alzheimer disease. We have previously rep orted that beta-amyloid immunoreactive deposits form in the brains of transgenic mice programmed for neuronal expression of the 751-amino ac id isoform of human beta-amyloid precursor protein (beta-APP751) and n ow describe that these animals also display Alz50 intraneuronal immuno reactivity similar to that seen in early Alzheimer disease. This sugge sts that abnormal beta-APP expression and/or beta-amyloid deposition p romotes pathogenic alterations in tau protein. The frequency of both b eta-amyloid deposition and Alz50-positive neurons was twice as prevale nt in brains from old (22 months) as compared to young (23 months) bet a-APP751 transgenic mice. This increase in histopathology with age in beta-APP751 transgenic mice parallels the time-dependent progression s een in the human disease.