Targeted delivery systems for biological therapies of inflammatory diseases

Introduction: Inflammatory diseases, including autoimmune diseases and autoinflammatory diseases, are characterized by the imbalance of pro-inflammatory cytokines and anti-inflammatory cytokines. Targeted systems allow for specific delivery and sustained release of biological agents to inflamed tissues and macrophages, hence reducing their side effects. Areas covered: This review discusses various targeting strategies for biological therapies of inflammatory diseases, with a focus on modulating macrophage functional polarization from an M1 to M2 phenotype. Furthermore, recent advances in the development of targeted delivery systems for gene therapy against inflammatory diseases including liposomal therapeutics, polymeric nanoparticles and microspheres, and multi-compartmental delivery systems are summarized. Expert opinion: Molecular advances have uncovered various targets for biological therapies against inflammatory diseases. Despite substantial promise, the potential translation from the bench to the clinic is limited due to poor systemic stability of the delivery systems, low tissue distribution, and safety concerns. In order to develop clinically translatable targeted delivery systems, thorough evaluation of the efficacy and toxicity in relevant animal models and in different inflammatory diseases is needed. In addition, issues related to long-term storage stability, scale-up and manufacturing of the systems need to be addressed.