Monomeric Aβ and metals reduce their cytotoxicities to each other

The present study has examined the effect of metals, such as iron and copper on the cytotoxicity of amyloid beta protein 1–40 (Aβ40). First, we showed that monomeric Aβ40 has stronger cytotoxicity than various type of aggregated Aβ40. Next we showed the addition of metals into the monomeric Aβ40 reduced the cytotoxicity of either monomeric Aβ40 or metals (iron and copper) although the addition of metals into monomeric Aβ40 resulted in a marked increase of aggregated form of Aβ40, which composed of β-sheeted Aβ40 and Aβ40 aggregation not characterized by β-sheet fibrils (coagrated Aβ40). Taken together, the metals and monomeric Aβ40 affect on each other and cause the reduction of their cell toxicity.