Transmission of mouse senile amyloidosis

In mouse senile amyloidosis, apolipoprotein A-II polymerizes into amyloid f ibrils (AApoAII) and deposits systemically. Peripheral injection of AApoAII fibrils into young mice induces systemic amyloidosis (Higuchi et at, 1998) . We isolated AApoAII amyloid fibrils from the livers of old R1.P1-Apoa2(c) mice and injected them with feeding needles into the stomachs of young R1. P1-Apoa2(c) mice for 5 consecutive days. After 2 months, all mice had AApoA II deposits in the lamina propria of the small intestine. Amyloid depositio n extended to the tongue, stomach, heart, and liver at 3 and 4 months after feeding. AApoAII suspended in drinking water also induced amyloidosis. Amy loid deposition was induced in young mice reared in the same cage for 3 mon ths with old mice who had severe amyloidosis. Detection of AApoAII in feces of old mice and induction of amyloidosis by the injection of an amyloid fr action of feces suggested the propagation of amyloidosis by eating feces. H ere, we substantiate the transmissibility of AApoAII amyloidosis and presen t a possible pathogenesis of amyloidosis, ie, oral transmission of amyloid fibril conformation, where we assert that exogenous amyloid fibrils act as templates and change the conformation of endogenous amyloid protein to poly merize into amyloid fibrils.