Perspectives and Limitations of Mesenchymal Stem Cell-Based Therapy for Corneal Injuries and Retinal Diseases.

The eye represents a highly specialized organ, with its main function being to convert light signals into electrical impulses. Any damage or disease of the eye induces a local inflammatory reaction that could be harmful for the specialized ocular cells. Therefore, the eye developed several immunoregulatory mechanisms which protect the ocular structures against deleterious immune reactions. This protection is ensured by the production of a variety of immunosuppressive molecules, which create the immune privilege of the eye. In addition, ocular cells are potent producers of numerous growth and trophic factors which support the survival and regeneration of diseased and damaged cells. If the immune privilege of the eye is interrupted and the regulatory mechanisms are not sufficiently effective, the eye disease can progress and result in worsening of vision or even blindness. In such cases, external immunotherapeutic interventions are needed. One perspective possibility of treatment is represented by mesenchymal stromal/stem cell (MSC) therapy. MSCs, which can be administered intraocularly or locally into diseased site, are potent producers of various immunoregulatory and regenerative molecules. The main advantages of MSC therapy include the safety of the treatment, the possibility to use autologous (patient's own) cells, and observations that the therapeutic properties of MSCs can be intentionally regulated by external factors during their preparation. In this review, we provide a survey of the immunoregulatory and regenerative mechanisms in the eye and describe the therapeutic potential of MSC application for corneal damages and retinal diseases.