Age-related evolution of amyloid burden, iron load, and MR relaxation times in a transgenic mouse model of Alzheimer's disease.

T1 and T2 magnetic resonance relaxation times have the potential to provide biomarkers of amyloid-beta deposition that could be helpful to the development of new therapies for Alzheimer's disease. Here, we measured T1 and T2 times as well as plaques and iron loads in APP/PS1 mice, which model brain amyloidosis, and control PS1 mice. Iron was mostly associated with amyloid deposits in APP/PS1 animals, while it was diffuse in the PS1 mice. T1 was negatively correlated with age in most structures in APP/PS1 animals. This may be related to the age-associated myelin loss described in APP/PS1 mice rather than to amyloid deposition. T2 in the subiculum of adult APP/PS1 animals was lower than in PS1 mice, which may be related to the very high amyloid and iron loads in this region. T2 in the subiculum could thus serve as an early marker of the amyloid pathology.