[Aluminum deposition and Ca-hydroxyapatite formation in frontal cortex tissue of amyotrophic lateral sclerosis]

To investigate a possible participatory role of an environmental metals in a pathogenetic process of amyotrophic lateral sclerosis (ALS), elementary and structural analyses of calcified substance in frontal cortex (percental gyrus) tissues of ALS patients were conducted using particle-induced X-ray emission (PIXE) and X-ray diffraction methods, as compared with control subjects. In the results of PIXE analysis, aluminum (Al) and calcium (Ca) contents in the frontal cortex tissues of the ALS patients were significantly increased with a high calcium (Ca)/phosphorus (P) Ca-hydroxyapatite (Ca-HAp). Although the content of peak ratio, as compared with those of control subjects. Only the Al content in the ALS patients showed significantly negative correlations with age at onset and/or at death. X-ray diffraction patterns from the sample (ashed at low temperature) of the frontal cortex tissues of the ALS patients were very similar to those from a standard sample of Ca-hydroxyapatite (Ca-HAp). Although the content of Ca-HAp in the mixed sample of frontal cortex tissues from the ten control subjects were not detectable (less than 3ppm), those of the ALS patients were markedly high, i.e., 111ppm in the mixed sample of five young patients with age under 60 and 168ppm in that of five old patients with age over 60. These results strongly indicated that Al may induce a calcifying degeneration in the CNS tissue of ALS patients, consequently leading to Ca-HAp formation as the final chemical compound.