Abstract: Methods, compounds and compositions are disclosed for treating amyloidogenic diseases, like Alzheimer's disease and type 2 diabetes, and particularly prion diseases associated with conversion of protease sensitive PrP (PrP-sen) to protease resistant PrP (PrP-res), by administering therapeutically effective amounts of a tetrapyrrole. Particular disclosed tetrapyrroles having this activity include phthalocyanines, deuteroporphyrins, and meso-substituted porphines. Complexes of certain of the pyrroles with metals or metal ions produce compounds that are particularly effective in converting the conversion of PrP-sen to PrP-sen. The treatment of the present invention is particularly suited for preventing or inhibiting the progression of prion related diseases, such as transmissible spongiform encephalopathies.

Abstract: The invention provides a method of treating a mammal having a condition associated with formation of amyloidogenic protein without deposition of amyloid plaques. This treatment includes administering to the mammal a pharmacologically effective amount of Congo Red or a pharmaceutically acceptable salt or derivative thereof to interfere with amyloidogenic protein formation or to destabilize amyloidogenic protein structures already formed in said mammal. The invention also provides a method of treating a mammal having a condition associated with deposition of amyloidogenic protein in plaques, and a method of inhibiting the transformation of PrP-sen to PrP-res in a tissue culture sample containing PrP-sen.