Artigos Científicos

Abstract

Epidemiological studies have revealed that increased aluminum (Al) concentration in drinking water increases the incidence of Alzheimer’s disease (senile dementia of Alzheimer’s disease type) (Martyn et al., 1989; Flaten, 1990; Neri and Hewitt, 1991). Al is a highly neurotoxic substance, and induces degeneration and death of nerve cells in the brains of humans and experimental animals (Mahurkar et al., 1973; Alfrey et al., 1976; Yumoto et al., 1992). We have reported that after subcutaneous injection of Al into rats, the numbers of dendrites and spines (postsynaptic structures of axodendritic synapses) of cortical nerve cells decreased markedly (Yumoto et al., 1992, 1993). These morphological changes were similar to those reported in the brains of patients with Alzheimer’s disease (Purpura, 1975).

INTRODUCTION
Epidemiological studies have revealed that increased aluminum (A 1) concentration in drinking water increases the incidence of Alzheimer's disease (senile dementia of Alzheimer's disease type) (Martyn et al., 1989; Flaten, 1990; Neri and Hewitt, 1991). Al is a highly neurotoxic substance, and induces degeneration and death of nerve cells in the brains of humans and experimental animals (Mahurkar et al., 1973; Alfrey et al., 1976; Yumoto et al., 1992). We have reported that after subcutaneous injection of Al into rats, the numbers of dendrites and spines (postsynaptic structures ofaxodendritic synapses) of cortical nerve cells decreased markedly (Yumoto et al., 1992, 1993). These morphological changes were similar to those reported in the brains of patients with Alzheimer's disease (Purpura, 1975).
High Al concentrations have been reported in the brains of patients with Alzheimer's disease (Crapper et aI., 1976, 1980; Perl and Brody, 1980; Good et aI., 1992; Yumoto et aI., 1992). However, Landsberg et ai. (1991, 1992) did not detect any Al in the brains of these patients using proton (2 MeV) microprobe particle-induced X-ray emission (PIXE) analysis, and concluded that Al has no pathogenic role in this disease. Recently, we demonstrated Al in the isolated brain cell nuclei from Alzheimer's disease patients using heavy ion (5 MeV Si3+) microprobe PIXE analysis (Yumoto et aI., 1996a). Heavy ion (3 MeV Si3+) microprobe PIXE analysis has a several fold higher sensitivity for Al detection than the 2 Mev proton microprobe PIXE analysis (Horino et aI., 1993a, 1993b). In this study, we further examined the presence of Al in the brains (hippocampus) of patients with Alzheimer's disease using secondary ion mass spectrometry (SIMS) and energy dispersive X-ray spectroscopy (EDX) to investigate the cause of Alzheimer's disease.