STUDIES ON THE RETINA AND THE PIGMENT-EPITHELIUM IN HEREDITARY CANINE CEROID LIPOFUSCINOSIS .3. MORPHOLOGIC ABNORMALITIES IN RETINAL NEURONS AND RETINAL PIGMENTED EPITHELIAL-CELLS

Abstract

The retina in 6 and 22 mo. old English setters with progressive blindness, ataxia, and muscle weakness demonstrated a marked accumulation of abnormal cytosomes within neurons and retinal pigmented epithelial cells. Ganglion cells contained abundant cytosomes with evenly spaced stacks of membranes; bipolar and amacrine cell cytosomes consisted of dense, amorphous material with closely spaced configurations of light and dark lines; cytosomes within photoreceptor cells contained faintly staining curved profiles. All 3 cytosomes resembled those in brain neurons of CCL [canine ceroid lipofuscinosis] dogs. In retinal pigmented epithelial cells prominent accumulations of lamellar fragments occurred, free in the cytoplasm or incorporated into melanin granules. These retinal abnormalities may be related to deficiencies of peroxidase and defects of lipid peroxidation. The pathologic and biochemical changes in these dogs are similar to those reported in human patients with Batten disease. These dogs provide a convenient model for the study of disease mechanisms and for therapeutic approaches to blindness in Batten disease.