Chemical state imaging of iron in nerve cells from a patient with Parkinsonism-dementia complex

X-ray fluorescence spectroscopy and Fe K-edge x-ray absorption near-edge structure spectroscopy were performed on postmortem human tissues containing nerve cells in order to investigate distributions and chemical states of iron. Specimens used in this study were obtained from the substantia nigra of a patient with Parkinsonism-dementia complex (PDC) of Guam and a control subject. Iron concentration was observed in the neuromelanin granules and in one of the glial cells surrounding the neuromelanin granules of the PDC patient. Iron was also detected in melanized neurons of the control subject. Chemical state imaging which separates Fe2+ and Fe3+ in iron compounds showed that the glial cell of the PDC patient has a higher concentration of Fe3+. Iron contained in the neuromelanin granules of the PDC patient was mixed states of Fe2+ and Fe3+.