Abstract
Abstract: :
Purpose: Age-related neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease) are characterized by intracellular accumulation of proteoglycan deposits (beta amyloid, Lewy bodis, Lafora bodies). They are considered as a specific alteration for these diseases. The aim of our studies was the ultrastructural description of similar deposits in the retina of aged humans apparently non affected by any neurodegenerative disease Methods: Twenty-three human retinas (aged from 67 to 87 years) were studies with transmission electron microscopy. The specimens were fixed immediately after surgical removal of the eyeballs, thus postmortem changes were insignificant Results: In seven retinas from the twenty-three specimens deposits were found ultrastructurally resembling to Lafora-bodies. Typically they are round or slightly ovoid, located in the processes of the neuroretinal cells, and formed by filamentary structures embedded in an amorphous or finely granulated material. They are surrounded by narrow cytoplasm in which neurotubules and a few small mitochondria can be seen. In some cases electrodense granules (lipofuscin?) can also be seen in the cytoplasm and inside the Lafora bodies. The retina surrounding the Lafora bodies showed no evident alterations. In five cases positive to Lafora bodies, focal thickenings of the basement membrane of retinal pigment epithelium were also observed Conclusion: Ultrastructural characteristics of Lafora bodies were described in the cytoplasm of neuroretinal cells of aged human retinas. In addition to the typical fibrillary structure, lipofuscin granules were found in the adjacent cytoplasm. These observations suggested that a similar metabolic disorder affecting both lipid and proteoglycan metabolism may occur in both retinal aging and. neurodegenerative diseases
Keywords: 561 retinal degenerations: cell biology • 472 microscopy: electron microscopy