Normalization of intracellular lysosomal hydrolases in I-cell disease fibroblasts with sucrose loading.

I-cell disease (ICD) is an hereditary inborn error of metabolism by lysosomal storage due to the multiple lysosomal hydrolases deficiency. Many inclusion materials are seen by phase contrast microscopy in cultured skin fibroblasts from the patients with ICD. We recently reported that the addition of 88 mM sucrose to the medium of cultured human skin fibroblasts from normal subjects induced several lysosomal hydrolases, but did not induce deficient hydrolases in lysosomal enzyme deficiencies (Kato, T., Okada, S., Ohshima, T., Inui, K., Yutaka, T., and Yabuuchi, H. (1981) Biochem. Int. 3, 551-556). This time sucrose loading was applied to the cultured skin fibroblasts from the patients with ICD. Incubation with 88 mM sucrose for more than 10 days exhibited significant effects. Biochemically, the activities of deficient hydrolases reached their normal levels, and morphologically, typical inclusion materials disappeared. These results indicate that sucrose enhanced synthesis of normal lysosomal enzymes and lysosome functions were normalized in ICD fibroblasts.