A mouse model for Niemann-Pick disease: phospholipid class and fatty acid composition of various tissues

Recently, a strain of mice bearing an autosomal recessive gene, spm, has been described. On the basis of clinical and pathological findings these mice have been suggested as a useful model of human Niemann-Pick disease. Phospholipids and their fatty acid compositions were analyzed for liver, spleen, whole brain, erythrocytes, and blood plasma from "Niemann-Pick"animals (spm/spm) and heterozygous controls (spm/+). Sphingomyelin and bis(monoacylglycero)phosphate accumulated in the liver and spleen of the affected mice, whereas no significant proportional change of phospholipids was observed in the whole brain. The phospholipid composition in erythrocytes and blood plasma of the homozygous mice was not different from that of the heterozygous controls. The fatty acyl chain profile of accumulated bis(monoacylglycero)phosphate was characterized by the high content (more than 80%) of unsaturated fatty acids; the main components were oleic acid, linoleic acid, and docosahexaenoic acid. A high unsaturation index of the fatty acyl chain was found in sphingomyelin accumulated in organs and in almost all phospholipids of brain, erythrocytes, and blood plasma of "Niemann-Pick" mice. It is conceivable that desaturation of fatty acids is enhanced in the "Niemann-Pick" mice.