Robust autophagy in optic nerves of experimental Creutzfeldt-Jakob disease and Gerstmann-Straussler-Scheinker disease

We report here autophagy in the optic nerve in experimental Gerstmann-Straussler-Scheinker disease (GSS) (Fujisaki-1) in mice and experimental Creutzfeldt-Jakob disease (CJD) (Echigo-1) in hamsters. Lesions of both experimental GSS in mice and experimental CJD in hamsters were practically indistinguishable. Briefly, they consisted of widespread Wallerian degeneration, spongiform change and a glial reaction. Numerous axonal swellings were seen. The latter were filled with numerous mitochondria and lysosomal electron-dense bodies. Autophagic vacuoles defined as structures bound in double membranes were readily found in many neuronal processes. The following description is organized as a sequence; however, the changes were all observed in the same specimens. First several empty double membrane-bound autophagic vacuoles were seen. In several of those vacuoles, the inner membrane was separated from the outer membrane and enclosed cargo. At the final stage, a mixture of empty autophagic vacuoles and electron-dense lysosomal vesicles was seen. Dystrophic neurites filled with a mixture of mitochondria, empty autophagic vacuoles and electron-dense lysosomal vesicles were interpreted as the final stage of autophagy. Of note, several areas were replaced with dense astrocytic gliosis.