ACCUMULATION OF ALUMINUM AND SILICON IN LIPOFUSCIN GRANULES

Since lipofuscin granules were concentrated in the high density fracti on in subcellular fractionation of autopsy brains of normal aged subje cts and of patients with Alzheimer's disease (AD), it was suspected th at inorganic materials accumulated in lipofuscin granules. Therefore, elemental analyses of clusters of lipofuscin granules in the high dens ity fraction were attempted by energy dispersive X-ray spectrometry wi th a scanning electron microscope. It was demonstrated that aluminium (Al) and silicon (Si) accumulated in some lipofuscin granules. Al has been considered as one of risk factors of AD since Al and Si were foun d in senile plaques (SP) and neurofibrillary tangles (NFT) of the brai ns with AD, although conflicting results also have been reported. It w as also demonstrated in this experiment by fluorescence microscopy of Bodian stained paraffin sections of AD brain that many SP and NFT cont ained lipofuscin granules, although lipofuscin granules were not alway s specific to those neuropathological changes. The results of this exp eriment imply that Al detected in SP and NFT is contained in lipofusci n granules.