AFM Investigation of the Aggregation Behavior of Alzheimer's Disease A beta Peptides

Amyoid peptides A beta 40 and A beta 42 are directly related to the Alzheimer's disease (AD) pathology. More specifically small alterations in the ratio A beta 42:A beta 40 have been shown to influence dramatically the synaptic function in vitro and in vivo. In this study we use Atomic Force Microscopy to investigate the morphology of the species formed during aggregation at different moments in time. In agreement with literature data, we found that a small increase of this ratio appears to delay the fibrilization process. Moreover, in the case of the A beta 42, known to be more pathogenic than A beta 40, small oligomers seem to coexist with higher molecular weight species from very early to very late moments in time. This suggests the continuous presence of intermediates that might have a synapto-toxic effect.status: publishe