The accumulation of cerebroside sulfates by fibroblasts in culture from patients with late infantile metachromatic leukodystrophy

Abstract

Late infantile metachromatic leukodystrophy (MLD) is a hereditable lipid storage disease characterized by a deficiency of the lysosomal enzyme arylsulfatase A and an accumulation of cerebroside sulfates (sulfatides) in certain tissues. Fibroblasts derived from skin biopsies of patients with MLD do not accumulate the pathognomonic metachromatically staining material observed in tissue sections, although they are grossly deficient in arylsulfatase A. It has been observed that fibroblasts from two patients with MLD did become metachromatic with cresyl violet and toluidine blue O when cultured in the presence of sulfatide, whereas control and heterozygous cells remained ametachromatic. Uptake studies with 35S-labeled sulfatides revealed that all cell strains tested incorporated the radioactive material but that only the MLD cells accumulated sufficient amounts to develop metachromasia. Analysis of the growth media established that control cells hydrolyzed the ingested sulfatide and excreted inorganic sulfate into the medium, while the MLD cells failed to produce any detectable degradation products. Induced inclusions in MLD fibroblasts may serve as a model for the study of this genetic disease in vitro.