AMYLOID DEPOSITION IN THE DIGESTIVE-TRACT IN CASEIN-INDUCED EXPERIMENTAL AMYLOIDOSIS IN MICE

In mice with casein-induced experimental amyloidosis, the incidence of amyloidosis in various organs was examined in relation to time, and t he extent of amyloid deposition in the digestive tract was investigate d. Amyloid was deposited first in the spleen, a little later in the di gestive tract, and then in the liver and kidney. In the digestive trac t, amyloid appeared simultaneously in the small and large intestine, a nd later in the glandular stomach. Amyloid deposition was most severe in the ileum, while it was not induced in the esophagus or non-glandul ar stomach. Initially, amyloid deposition was observed along the small blood vessels and/or epithelial basement membranes in the lamina prop ria mucosa (LPM); it then extended to the stroma in the LPM. Amyloid d eposition in each portion of the digestive tract had characteristic pa tterns in the LPM. Deposition of amyloid fibrils was confirmed by elec tron microscopy. The results suggest that the gastrointestinal biopsy used widely to diagnose human reactive amyloidosis is a sensitive earl y indicator of amyloidosis.