Studies on the Mechanism of Early Onset Macular Degeneration in Cynomolgus ( Macaca fascicularis) Monkeys. I. Abnormal Concentrations of Two Proteins in the Retina

Cynomolgus ( Macaca fascicularis) monkeys from three families, which showed symptoms of early onset macular degeneration was studied. Two proteins, albumin and glyceraldehyde 3-phosphate dehydrogenase, were found to have markedly altered concentrations in whole retina of the monkeys with early onset macular degeneration, compared with normal controls. SDS–polyacrylamide gel patterns detected a 40–70% increase in the concentration of albumin and about 65% decrease in the concentration of glyceraldehyde 3-phosphate dehydrogenase in these affected retinas. There was however no significant difference in the relative concentrations of albumin in the plasma samples of affected and normal monkeys belonging to the three families studied and to an unrelated family. These initial findings suggest that degradative as well as antioxidant enzymes might be involved in the mechanisms leading to macular degeneration. In addition, the results also correlate with a possible role of these two proteins in H 2O 2toxicity and appear to indicate that oxidative stress is significant in the etiology of early onset macular degeneration.