Immunoisolation cell therapy for CNS diseases.

Delivery of potentially therapeutic drugs to the brain is hindered by the blood-brain barrier (BBB), which restricts the diffusion of drugs from the vasculature to the brain parenchyma. One means of overcoming the BBB is with cellular implants that produce and deliver therapeutic molecules directly into the CNS region of interest. In this paper we describe the current status of one iteration of cell-based therapy that uses xenogeneic cells encased within a selectively permeable polymeric membrane; this is known as immunoisolation. For the purposes of this review, cell immunoisolation for treating CNS diseases is presented in terms of device configurations, membrane manufacturing, characterization in relevant preclinical model systems, and the current status of clinical trials.