BIOCHEMICAL MAPPING OF NEUROFIBRILLARY DEGENERATION IN A CASE OF PROGRESSIVE SUPRANUCLEAR PALSY - EVIDENCE FOR GENERAL CORTICAL INVOLVEMENT

A biochemical study was performed to quantify and map the neurodegener ating process in cortical and subcortical brain areas from a case of p rogressive supranuclear palsy (PSP). Our approach was based on a Weste rn blot analysis of pathological Tau proteins, which are the basic com ponents of neurofibrillary lesions. We found that: (i) the abnormal Ta u proteins can be detected in all cortical areas, sometimes in larger amounts than in some subcortical areas; (ii) these abnormal Tau protei ns consist of a doublet called Tau 64 and 69, except for in the entorh inal cortex where we detected, as for Alzheimer brains, the triplet of Tau proteins called Tau 55, 64 and 69; (iii) the amounts of abnormal Tau proteins were higher in some neocortical regions, especially in th e frontal lobe, than in the hippocampal formation. Our results show th at the neocortical pathology in PSP, as revealed by the presence of pa thological proteins, is more extended than thought so far. Our biochem ical approach appears to be more sensitive than the immunohistochemica l one and can clearly differentiates between two types of neurofibrill ary pathology, the Alzheimer type with a triplet of abnormal Tau prote ins (Tau 55, 64 and 69) and the PSP type with a characteristic doublet (Tau 64 and 69).