This is likely to be pathologically important, and precedes amyloid-induced increases of ROS in neurons.42 ROS derived from mitochondria have been implicated in ageing and associated with Ca2+ mobilisation in astrocytes.43 In the present study, NADPH oxidase(s) appear to be major contributors to the increased ROS levels (see ref. 44 and Figure 3). This evidence concerns the gene FMO5 and amyloidosis.