Stem cell sources and therapeutic approaches for central nervous system and neural retinal disorders

In the past decades, stem cell biology has made a profound impact on our views of mammalian development as well as opened new avenues in regenerative medicine. The potential of stem cells to differentiate into various cell types of the body is the principal reason they are being explored in treatments for diseases in which there may be dysfunctional cells and/or loss of healthy cells due to disease. In addition, other properties are unique to stem cells; their endogenous trophic support, ability to home to sites of pathological entities, and stability in culture, which allows genetic manipulation, are also being utilized to formulate stem cell-based therapy for central nervous system (CNS) disorders. In this review, the authors will review key characteristics of embryonic and somatic (adult) stem cells, consider therapeutic strategies employed in stem cell therapy, and discuss the recent advances made in stem cell-based therapy for a number of progressive neurodegenerative diseases in the CNS as well as neuronal degeneration secondary to other abnormalities and injuries. Although a great deal of progress has been made in our knowledge of stem cells and their utility in treating CNS disorders, much still needs to be elucidated regarding the biology of the stem cells and the pathogenesis of targeted CNS diseases to maximize therapeutic benefits. Nonetheless, stem cells present tremendous promise in the treatment of a variety of neurodegenerative diseases.