Micro-organ compositions and methods of implanting into the central nervous system (CNS) for the treatment of CNS-related diseases are encompassed. Specifically, the disclosure provides methods for treating disorders including cancer and lysosomal storage diseases, the methods comprising implanting a micro-organ into the CNS, wherein the micro-organ secretes a recombinant protein, and wherein the micro-organ is maintained in the CNS, and secretes protein, for at least seven days.
