Ligand specific effects on aluminum incorporation and toxicity in neurons and astrocytes

Aluminum is present in many manufactured foods and medicines and is added t o drinking water for purification purposes. Tt has been proposed that alumi num is a contributing factors to several neurodegenerative disorders such a s Alzheimer's disease. However, this remains controversial primarily due to the unusual properties of aluminum and a lack of information on its cellul ar sites of action. To resolve some of these questions, we have examined al uminum uptake in both neuronal and astroglial cells as well as the role of metal speciation. The relative accumulation of four aluminum salts, aluminu m maltolate, aluminum lactate, aluminum chloride and aluminum fluoride, was investigated and correlated with cell viability and intracellular distribu tion as determined by morin staining. Significant differences in aluminum i ncorporation and toxicity were observed in both neuronal and glia cells wit h the largest effects exhibited by the maltol species. This was accompanied by a nuclear accumulation in the neuronal cell line that was contrasted by the perinuclear, vesicular distribution in astrocytes that partially co-lo calized with cathepsin D, a lysosomal marker. These findings demonstrate di fferences in aluminum species and highlights the importance of these factor s in modulating the toxic effect of aluminum. (C) 2000 Elsevier Science B.V . All rights reserved.