Single and multiple transgenic mice as models for Alzheimer's disease.

Transgenic mice expressing in brain different mutant forms of the Amyloid Precursor Protein, develop functional, cognitive and pathological defects which resemble or are reminiscent of symptoms observed in Alzheimer's disease (AD) patients. The late development of amyloid plaques in aging transgenic APP mice is needed to warrant that the earlier behavioural and cognitive defects are informative for the human disorder. We describe and discuss our work, the rationale behind the approach and the techniques used to generate these APP transgenic mice, including specific experimental problems. The APP transgenic mouse models are being comprehensively characterized and offer excellent perspectives for the study and definition of early biochemical and pathological aspects that are not accessible in human AD patients. The ongoing combination by breeding with other transgenic mouse strains, i.e. mice overexpressing human Presenilin 1, ApoE 4 and protein tau to generate "multiple" transgenic mice, offer additional potential to define the pathological interactions of these genetic factors, known to be involved, directly or indirectly, in dementia of the Alzheimer type. Finally, it must be the aim to obtain transgenic mice that not only model amyloidogenesis, but also the neurofibrillary tangle pathology and the involvement of protein tau.