Stem Cell therapy in Pediatric Endocrine Disorders

In the last decade, stem cell therapy has emerged as a promising treatment modality in the treatment of autoimmune diseases. Stem cells are primitive undifferentiated cells capable of self-renewal and differentiation into to virtually any tissue or organ [1]. They demonstrate infinite regenerative capacity additionally to the ability relocate and differentiate where needed. There are three categories of stem cells namely embryonic stem cells (ESCs), cord blood (CB) stem cells, and adult stem cells (ASCs) [2]. Embryonic stem cells originate in, and are derived from the inner cell mass of the human blastocyst and have latent differentiation capacity for endodermal, mesodermal, and ectodermal cell line origins. Cord blood stem cells are derived from umbilical cord hematological tissue and differentiate into adipogenic, osteogenic, chondrogenic, bone marrow tissues and hematological cell types [3-5]. Adult stem cells are undifferentiated cells found among differentiated cells in a tissue or organ and exhibit the property of trans-differentiation or plasticity. Through isolation and culturing procedures combined with targeted manipulation, such cells can be used to replace diseased, damaged, or dead terminally differentiated cells inherently incapable of self-reorganization, restructuring and selfregenerative capacities. Studies both vitro and vivo exhibit results i n d i c a t i n g s t e m c e l l a b i l i t y t o e x e r t o b s e r v a b l e immunomodulatory effects [3, 4, 6, 7]. Evidence demonstrates that mesenchymal stem cells (MSCs) have the ability to regulate T-cell function by promoting regulatory dendritic cell (DC) generation. MSCs also modulate alteration of dendritic cell cytokine profiles by effecting augmented secretion of regulatory cytokine chemical messengers such as IL-10 and by causing a decrease in production of inflammatory cytokines such as Interferon gamma, IL-12 and Tumor Necrosis Factor alpha resulting in an anti-inflammatory or t o l e ra n t d e n d r i t i c c e l l p h e n o t y p e [ 8 , 9 ] . T h e s e immunomodulatory effects have sparked interest in stem cells for treatment of autoimmune disorders and a number of clinical trials are underway in this area. MSCs have been employed with some success in treatment of type 1 diabetes, Parkinson's disease, autoimmune thyroid disorders, graft versus host disease (GVHD), Crohn's disease, multiple sclerosis, and in systemic lupus erythematosus [10-13]. Application in leukemia or chemotherapy