Diseases of the Retinal Pigment Epithelium-Photoreceptor Complex in Nonrodent Animal Models

Book Overview: The retinal pigment epithelium is a critical tissue within the eye. It lies directly behind the retina, where it provides metabolic support to the photoreceptors and controls their local environment. As a result, the RPE is vital to retinal function, but also a site of aging and disease that cause dysfunction and visual loss. This book brings together comprehensive reviews of basic and clinical science concerning the RPE. It is organized to juxtapose chapters on RPE disease with chapters on the underlying pathophysiology. These include up-to-date accounts of growth factors, laser effects, proliferative vitreoretinopathy, Bruch\u27s membrane pathology, as well as new diagnostic tools such as ocular coherence tomography, in vivo imaging of lipofuscin and non-photic electrical responses. Other chapters cover pharmacology and toxicology, mechanisms of retinal adhesion and detachment, RPE pigments and transport, congenital and dystrophic diseases, animal models of RPE disease, and different aspects of age-related macular degeneration. The history and evolutionary aspects of the RPE are also presented. The contributing authors are experienced clinicians and eminent basic scientists who work on this critical part of the eye. The book will be a valuable resource for anyone interested in the eye, and a necessity for specialists in the fields of retinal physiology and retinal disease

Arylsulfatase B Activity in Cultured Retinal Pigment Epithelium: Regional Studies in Feline Mucopolysaccharidosis VI

eline mucopolysaccharidosis VI (MPS VI) is a recessively inherited lysosomal storage disease resulting from a deficiency of arylsulfatase B (ASB). Previous histopathologic findings have indicated that the disease is expressed morphologically in non-pigmented retinal pigment epithelial cells (RPE) in the posterior pole and superior equatorial regions by the accumulation of vacuolated inclusions and eventual cellular hypertrophy, while pigmented regions in the periphery are minimally affected. To determine if the regional and age-dependent variations in disease severity result from differences in residual enzyme activity, primary cultures of feline MPS Vl-affected RPE were initiated from defined regions of the eye and maintained in vitro for 14 days. Cultures initiated from nonpigmented areas of affected adult eyes (posterior pole, superior equatorial) were more diseased than those from pigmented (inferior-equatorial, peripheral) areas. In the nonpigmented cultures, the disease was expressed by the accumulation of single membrane-bound inclusions and cellular hypertrophy. These inclusions were indistinguishable in their morphologic appearance and distribution from those found in situ. In contrast, the cultures initiated from pigmented areas remained normal or minimally affected. The same spatial disease distribution was present in young affected eyes, but the expression of the disease was much less severe. It is apparent that temporal, spatial, and pigmentation factors were correlated with disease expression in vitro as well as in situ. Arylsulfatase B activity was measured biochemically, and found to be deficient in all regions of young and adult eyes. It was notable that there was no correlation between the level of residual enzyme activity, and the pigmentation or spatial position from which the cells were obtained. Thus, variations in residual enzyme activities cannot account for the spatial and temporal differences in disease severity. Invest Ophthalmol Vi