Neutron activation analysis of scalp hair from ALS patients and residents in the Kii Peninsula, Japan.

The aim of this study was to evaluate the accumulation of transition metals in the scalp hair of amyotrophic lateral sclerosis (ALS) patients in the Koza/Kozagawa/Kushimoto (K) area (K-ALS) in the Kii Peninsula, Japan. Metal contents were measured in the unpermed, undyed hair samples of 88 K-residents, 20 controls, 7 K-ALS patients, and 10 sporadic ALS patients using neutron activation analysis at the Research Reactor Institute, Kyoto University. A human hair standard and elemental standards were used as comparative standards. The contents of Zn, Mn, and V were higher, while that of S was lower in K-ALS patients than in the controls. The content of Mn in K-ALS patients negatively correlated with clinical durations. The content of Al was significantly higher in K-residents than in the controls, with 15.9 % of K-residents having high Mn contents over the 75th percentile of the controls. The contents of Zn, Mn, and V were high in the scalp hair of K-ALS patients and correlated with the content of Al. The accumulation of these transition metals may chronically increase metal-induced oxidative stress, which may, in turn, trigger the neuronal degeneration associated with K-ALS.