Secretion of lysosomal hydrolases by cultured human amnion epithelial cells

Primary microcultures of human amnion epithelial cells were established, starting from sterile term placentae. Over a period of 1 week in culture, the epithelial cells release into the extracellular medium substantial amounts of some lysosomal hydrolases, such as sphingomyelinase, N-acetyl-beta-glucosaminidase, alpha-fucosidase, beta-glucuronidase, alpha-mannosidase, and arylsulfatase. Judging from experiments conducted with the protein synthesis inhibitor, cycloheximide, the enzymes released are not newly synthesized forms, but very likely derive from lysosomes. The constitutive secretion of lysosomal enzymes, coupled with lack of immunogenicity, makes amnion epithelial cells a convenient source of enzymes for implantation in attempts of enzyme replacement therapies.