LIPIDS OF PLASMA, RETINA, AND RETINAL-PIGMENT EPITHELIUM IN SWEDISH BRIARD DOGS WITH A SLOWLY PROGRESSIVE-RETINAL-DYSTROPHY

Reduced blood levels of long chain polyunsaturated fatty acids have be en reported in humans and animals with inherited retinal degenerations . The lipid and fatty acid compositions of plasma, retina, and retinal pigment epithelium of the Swedish Briard dog, which has a very slowly progressive retinal dystrophy that is inherited in an autosomal reces sive manner were analysed. The lipid class composition of the pigment epithelium was not different between affected and normal dogs; however , significant differences were found between the retinas of the two gr oups. Affected dogs had relatively more phosphatidylethanolamine and p hosphatidylinositol and less phosphatidylcholine than normal dogs. The re was no difference in the fatty acid compositions of plasma and reti nal pigment epithelium between affected and normal dogs. However, the retinas of affected dogs had significantly lower levels of 22:5n-3 and 22:6n3 and higher levels of 18:2n-6, 20:4n-6, and 22:5n-6. The total n-3 fatty acid content was significantly lower in affected retinas (P < 0.001), whereas the content of n-6 fatty acids was significantly hig her in affected retinas (P < 0.001). These studies provide evidence fo r yet another animal model of inherited retinal degeneration with a de fect in retinal polyunsaturated fatty acid metabolism. The fatty acid pattern in affected dogs resembles that seen in the retina in n-3 fatt y acid deficiency. (C) 1997 Academic Press Limited.