Systemically Administered, Target-Specific Therapeutic Recombinant Proteins and Nanoparticles for Regenerative Medicine.

Growth factors, chemokines, and cytokines responsible for tissue regeneration have been identified. Their therapeutic usage in humans is almost nonexistent because of the difficulty in maintaining their bioactivity in the protease-rich milieu of injured tissues. Safety concerns have ruled out the systemic administration of growth factors. Angiogenic vasculature forming in the regenerating tissues has unique molecular structures, so-called "zip/postal codes". These unique vascular zip codes provide an opportunity for target-specific delivery of systemically administered therapeutics to tissue injuries by ligands (using peptides or antibodies as a delivery vehicle) binding to these specific structures. Molecules with therapeutic potential can also be packaged into nanocarriers which then can be targeted to the desired location by placing large number of peptides on the nanoparticle. The targeted delivery of systemically administered recombinant proteins to the injured tissue is hopefully rapidly advanced to provide new therapeutics to regenerative medicine.