Stem Cells Derived from Human Exfoliated Deciduous Teeth (SHED) in Neuronal Disorders: A Review

Most conventional treatments for neurodegenerative diseases fail due to their focus on neuroprotection rather than neurorestoration. Stem cell-based therapies are becoming a potential treatment option for neurodegenerative diseases as they can home in, engraft, differentiate and produce factors for CNS recovery. Stem cells derived from human dental pulp tissue differ from other sources of mesenchymal stem cells due to their embryonic neural crest origin and neurotrophic property. These include both Dental Pulp Stem Cells (DPSCs) from dental pulp tissues of human permanent teeth and Stem cells from Human Exfoliated Deciduous teeth (SHED). SHED offers many advantages over other types of MSCs, such as good proliferative potential, minimal invasive procurement, neuronal differentiation and neurotrophic capacity, and negligible ethical concerns. The therapeutic potential of SHED is attributed to the paracrine action of extracellularly released secreted factors, specifically the secretome, of which exosomes are a key component. SHED and its conditioned media can be effective in neurodegeneration through multiple mechanisms, including cell replacement, paracrine effects, angiogenesis, synaptogenesis, immunomodulation, and apoptosis inhibition, and SHED exosomes offer an ideal refined bed-to-bench formulation in neurodegenerative disorders. However, in spite of these advantages, there are still some limitations of SHED exosome therapy, such as the effectiveness of long-term storage of SHED and their exosomes, the development of a robust GMP-grade manufacturing protocol, optimization of the route of administration, and evaluation of the efficacy and safety in humans. In this review, we have addressed the isolation, collection and properties of SHED along with its therapeutic potential on in vitro and in vivo neuronal disorder models as evident from the published literature.