Stem cells are considered as key therapeutic tools in the field of regenerative medicine.In the last decade,based on a growing body of knowledge about their mechanisms of action,a new way of exploring the therapeutic potential of stem cells without the need for cell transplantation has been evidenced.This approach,called cell-free therapy,uses stem cells as a source of therapeutic molecules rather than the therapeutic agent per se,and several studies have shown relevant therapeutic effects under a variety of experimental conditions,including nervous system disorders.