Correction of ornithine accumulation prevents retinal degeneration in a mouse model of gyrate atrophy of the choroid and retina

AUTOR(ES)

Wang, Tao

FONTE

The National Academy of Sciences

RESUMO

Deficiency of ornithine-δ-aminotransferase (OAT) in humans results in gyrate atrophy of the choroid and retina (GA), an autosomal recessive disorder characterized by ornithine accumulation and a progressive chorioretinal degeneration of unknown pathogenesis. To determine whether chronic, systemic reduction of ornithine can prevent this form of retinal degeneration, we used an arginine-restricted diet to maintain long term reduction of ornithine in a mouse model of OAT-deficiency (Oat−/−) produced by gene targeting. We evaluated the mice over a 12-month period by measurement of plasma amino acids, electroretinograms, and retinal histologic and ultrastructural studies. We found that an arginine-restricted diet substantially reduces plasma ornithine levels and completely prevents retinal degeneration in Oat−/−. This result indicates that ornithine accumulation is a necessary factor in the pathophysiology of the retinal degeneration in GA and that restoration of OAT activity in retina is not required for effective treatment of GA.

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