Expression of hMTHI in the hippocampi of control and Alzheimer's disease

The oxidized purine nucleoside triphosphatase, hMTHI, has a critical role towards preventing errors caused by oxidized purine nucleoside triphosphates such as 8-oxo-dGTP and 2-hydroxy-dATP. We investigated the immunohistochemical expression of hMTHI in human hippocampal postmortem tissues representing non-neurological disease and Alzheimer's disease (AD). In the non-neurological subjects the hMTHI protein was enriched in the stratum lucidum at CA3 corresponding to mossy fiber synapses. In AD subjects, the synaptic immunoreactivities at CA3 were significantly decreased, whereas they tended to be increased at the entorhinal cortex. We suggest that the expression of hMTHI indicates indirect evidence of oxidative stress and its regulation is regionally differentiated in AD.