Hepcidin and ferroportin expression in APP-tg mice. Immunofluorescence staining of intraneuronal Aβ and intracellular hepcidin revealed an almost complete overlap in cortical neurons in two month old APP-tg mice (a), as well as in cortical extracellular plaques in 4-6 month old APP-tg mice (b, c indicated with white arrow). By 10 months, more severe pathology was evident with amyloid plaques increased in size and quantity and distributed throughout the cortex in close proximity to blood vessels (d), olfactory bulb (e), dentate gyrus, subiculum and the CA1 layer (f). With disease progression, hepcidin levels were reduced in the dentate gyrus (f, white arrow). At 2 months, FPN staining was seen in all cortical neurons, co-localising with the neuronal marker βIII tubulin (g-i). Hepcidin was seen around the periphery of the maturing plaques (j) along with glial activation ( identified by GFAP, k), while with disease progression ferroportin levels were reduced with expression limited to fibrillary axons (l, white arrow). Scale bar a-b 150 μm, c-g, 100 μm, j 150 μm, h-k 50 μm, l 25 μm.